Rehydration
- Is the process of restoring body fluids which was lost by excessive vomiting and diarrhea
- Losses water and salts from the body
- Body fluids become more concentrated than normal
Two Methods of Rehydratrion
- Intravenous (IV)
- Is for patients that are unable to keep down oral drink (due to excessive vomiting and age)
- IV solutions contain sterile water with small amounts of salt
- Oral Rehydratrion Method (ORL)
- Is a drink which is taken in orally
- Contains water with a balance of water, salt and sugar for respiration to restore normal concentration of body fluids
Liver
Functions of the liver
- Production of Bile salts
- When red blood cells break down in the liver yellow and green pigments are formed
- These pigments are removed by the liver through the blood and excreted in bile
- Blood Sugar regulation
- With the action of hormone (secreted by the pancreas)
- Insulin- Coverts glycogen stored in the liver to glucose
- Glucogen- Converts glucose to glycogen and is stored in the liver
- Storage of Iron
- When red blood cells break down iron from hemoglobin is stored
- Deamination
- Removes the amino (NH ) group from amino acids and is converted to urea and removed by the blood
- Detoxication
- Poisonous substances are removed from blood and converted to harmless compounds and excreted in urine by the liver,
- Storage of vitamins
- Fat soluble vitamins A and D are stored in the liver
Blood circulation
Composition of Blood
1. Red Blood Cells (Erythrocytes)
- Made in the red bone marrow- sternum, ribs and vertebrae
- Breaks down in the liver or spleen (lives about 4 months )
Function
- Carry oxygenated blood to body cells from the heart
Adaptation to carry out there function
- Absence of nucleus- provides a greater surface area to carry more oxygen
- Contains a red pigment hemoglobin-allows oxygen to readily combine (efficient)
- Present in large numbers
- Biconcave (disc shaped) and minute (small)- an pass through capillaries easily
- Elastic and thin membrane- allows oxygen to diffuse easily
Process of Transporting Oxygen
- Oxygen combines with hemoglobin in regions where there is a high concentration of oxygen
- Forms an unstable compound oxyhemoglobin
- Oxygen is released in regions where there is a low concentration of oxygen
2. White Blood Cells (Leucocytes)
Mainly two types
- Agranulocytes
- Granulocytes
- Neutrophils
- Basophils
- Eosinophils
Agranulocytes
- Lymphocytes
- T Cells (Produced in the Bone Marrow Undergo Maturation in the Thymus)
- Killer T Cells
- Helper T Cells
- B-Cells (Produced in the Bone Marrow and Undergo Maturation in the Bone Marrow)
- Plasma Cells
- Memory Cells
- Killer T- cells have receptor molecules on their surface in which antibodies stick surface to inactivate the antigen
- Helper T- cells stimulate the production of antibodies stimulate phagocytosis
- When B-cells are stimulated during an invasion
- They differentiate into Plasma cells and Memory cells
- Plasma cells produce the specific antibodies against the antigen
- Memory Cells remain in the circulation retaining the memory in case of a secondary invasion
- Where Memory cells quickly stimulate the production of that particular antibody when a antigen enters the body
Monocytes
- Monocytes is one of the main phagocytes (under phagocytosis)
- When Monocytes enter the blood they are referred to as macrophages
Granulocytes
- Basophlis and Eosinophils respond to allergic reaction/ reaction against parasite
- Neutrophlis are the main phagocytes
Phagocytosis
- Phagocytes engulf bacteria
- Release enzymes in the cytoplasm
- Digest/destroy bacteria
- Preventing the spread of pathogens
3. Platelets
Function
- Are tiny fragments of bone which play an important role in blood clotting
4. Plasma
Function
- Is a pale yellow fluid which provides a medium pf transport for substance in the blood
Blood Clotting
- Platelets adhere to the damaged area
- Platelets produce thrombokinase
- Acts as an enzyme and converts prothrombin to thrombin
- Thrombin acts on soluble fibrinogen
- And converts it to insoluble fibrin with the help of vitamin K and calcium ions
- Fibrin for a thread like network of fibres
- The mesh of fibres traps the red blood cells and forms a clot
- Living cells divide and repair the wound
- White blood cells collect at the wound and destroy any pathogens
- The network of fibres shrinks and forms a hard dry scab that protects the wound from external damage
Blood vessels
Capillaries
Adaptation
- Single cell thickness allows blood cells to easily pass through
- Tubular
- Size of the lumen is the size of a red blood cell
- Carries arterioles and venules
Double Circulation
- Systemic circulation- pumps blood around the whole body
(except the upper body region)
- Pulmonary circulation-pumps blood from the heart to the lungs and heart
Heart
- Is situated in the thoracic cavity
- Surrounded by a tough pericardium membrane
- The pericardium fluid reduces the friction between the heart and the pericardium membrane
- The septum completely separates the left side of the heart from the right.
- (This prevents the oxygenated blood from mixing with deoxygenated blood)
Chambers & Valves of the heart
Pulmonary Capillaries (Differences)
Coronary Arteries
Coronary arteries supply the heart muscles with oxygen and glucose
If the Coronary Arteries become blocked?
- Blood cannot reach heart muscles
- Glucose and Oxygen supply to heart muscles is inadequate
- Heart muscles cannot respire
- And release energy for contractions
- Heart muscles die
- Heart stops beating
How Coronary Arteries become blocked?
- High fat diet
- Obesity
- Stress
- Smoking
How to reduce the chance of having blocked Coronary Arteries?
- Reduce the intake of fats (Lower Cholesterol Level)
- Reduce the intake of salts
- Consume a greater proportion of fibre
- Stop smoking
Valves
Functioning
- Blood is forced backwards
- Flaps of the valves (contract) tilt up
- Closing the passage way
- Prevents the back flow of blood
Effect of Adrenaline on the heart
- Adrenaline produced
- Causes the heart rate to increase
- Supplies working muscles with more oxygen and glucose
Why the heart beats faster during vigorous exercise?
- During vigorous exercise working muscles respire rapidly
- To meet the energy demand for muscle contraction
- This requires a supply of glucose and oxygen from blood
- The heart beats faster to pump more blood
- As result produces carbon dioxide
- Carbon dioxide is removed by the blood
Effect of smoking on the heart
- Causes blockage of and narrowing of coronary arteries
- Fat (cholesterol) aids the process of blockage
- Less oxygen and glucose is supplied to heart muscles
- Anaerobic respiration takes place in the heart muscles
- Lactic acid accumulates
- Nicotine /Carbon monoxide
- Increases heart rate
Diseases Involved with Blood
Anemia
- Is the shortage of red blood cells
- Bone marrow is not able to make enough hemoglobin or red blood cells
- Excessive destruction of red blood cells
- Low intake of iron in the diet
Effects
- Less oxygen is transported to body cells
- Feels weak
- Looks pale
Genetically Inherited Diseases
Sickle cell Anemia (Autosomal Inheritance)
- Is where hemoglobin molecules have slightly different composition
- Causing them to form rod like structures
- Allowing less oxygen to be carried
Hemophilia (Sex-Linked Inheritance)
- Is a condition in which blood takes along time to clot
- When it takes a long time to clot more blood is lost
Exchange between Capillaries and Cells
- The arterial (artery) end of the capillary forces blood plasma to leak out of the capillary
- The blood plasma is rich in nutrients
- Once blood plasma leaks out the capillary it is known as tissue fluid
- The tissues fluid is similar in composition to blood plasma but contains lower concentration of plasma proteins
- The tissue fluid fills up a space between the cells and the capillary called tissue space
- From the tissue fluid substances such as oxygen and glucose pass into the cells
- And waste products from the cells pass into the tissue fluid
- This happens by the process of diffusion from a greater concentration to a lower concentration down the concentration gradient
- Extra tissue fluid seeps back into the lymphatic vessel
- Blood pressure increases and make hart work harder
- Leads to heart attack/ heart diseases
Lymphatic System
*Lymph is the fluid in lymph vessels
Formation of Lymph
- Is when excess tissue fluid drains back into the lymph vessel (lacteals)
Composition of Lymph
- Contains less proteins
- Similar composition to plasma
- More white blood cells
Lacteal-are vessels from the villi present in the small intestine which open up to the lymphatic system
Lymph nodes- are swellings on the lymphatics filled with a network of fibres and attached to these fibres are macrophages which ingest any foreign particles in lymph
Lymph vessels- contain valves and depend on the movement of the body to transport the lymph around the body
Lymph Organ- Spleen, produces lymphocytes and contains other white blood cells (Example Macrophages)
Immune System
Immunity
- Is the resistance provided by the body against harmful microorganisms
- Before symptoms appear
- But the patient does not develop the disease
Innate Immunity
- Is the inbuilt immunity provided by the body since birth
Acquired Immunity
- Is the immunity gained after birth where the body itself has the ability to produce it own antibodies
Acquired Active Immunity
Natural Acquired Immunity
- White Blood Cells are stimulated
- Detect the antigens
- B-cells (Plasma cells) Produce antibodies
- And Destroy the antigens by
-
Neutralization- Antitoxins neutralize the poisons released by antigen
-
Agglutination- Clump the antigens
-
Opsonization- Attach to the surface of the antigen and making it easier for phagocytes to engulf
-
Precipitation- Antibodies are precipitated on soluble antigens and become inactive
- The symptoms may appear as it takes a long time recognize the antigen and produce the antibody
- B-cells (Memory cells) remain in the blood retaining the memory in case of secondary attack
Artificial Acquired Immunity
- Artificial acquired immunity is gained as a result of injecting a treated pathogen or toxin
- This stimulates the immune system
- White blood cells respond to the antigen
- Produce specific antibodies for a specific antigen
- Antibodies are released into the blood
- Destroy antigens
- Mild symptoms may appear as immune system is not weak
- During a secondary attack memory cells stimulate the production of the correct antibody
- Preventing a specific disease (increases population of a particular pathogen)
Passive Acquired Immunity
- Is the immunity provide by antibodies being injected or passed into the body as the body does not produces its own antibodies
Difference between Active & Passive Immunity
Reaction given by body due to the entry of microorganisms
- Phagocytes (Monocytes and Neutrophlis) engulf bacteria
- Digest/ destroy bacteria
- Prevents the spread of pathogens
- Lymphocytes produce antibodies
- Specific antibodies act on specific antigen
- Antibodies combat antigen in many ways (Neutralization, Agglutination, Opsonization, Precipitation)
- Memory cells remain in the circulation retaining the memory in case of a secondary invasion
Gaseous Exchange In Human
Respiratory system
Lungs Structure
- The lungs are situated in the thorax
- Trachea allows air to pass in and out of the lungs
- Incomplete rings of cartilage prevent the trachea and bronchi from collapsing during inspiration
- Trachea divides to two main branches- Bronchi (Bronchus)
- The two bronchi divide further to Bronchioles
- Bronchioles divide into tiny air sacs- Alveoli (Alveolus)
- The left side of the lung has two lobes and the right side has 3 lobes
- The lungs are surrounded by a pleural membrane which secretes pleural fluid, reducing the friction between the lungs and the rib cage
- The thoracic cavity is protected by the rib cage
Ventilation
-
Is the process which involves taking in and expelling air out of the lungs
Gaseous Exchange in Alveoli
- Lungs gains oxygen
- Oxygen passes into the red blood cells
- Entering through the pulmonary artery
- Form oxyhaemoglobin
- Loses carbon dioxide
- By diffusion
- From a greater concentration to lower concentration
- Between blood and alveolar air
- Oxygenated red blood cells leave the lungs through the pulmonary vein
Removal of water vapor by thin films
Temperature falls
Air is at a lower temperature than blood
Causing water in the film to evaporate
Water evaporated from the film is replaced by movement of water out of the blood
Difference between Exhaled and Inhaled Air
Adaptation for Efficient Gaseous Exchange
- Alveolar wall is one cell thick (thin)
- Helps gaseous exchange/ diffusion
- Surrounded by a dense network of capillaries
- Maintains steep concentration gradient (ventilation of lungs)
- Alveoli have moist lining
- Enable gases to dissolve and diffuse
Cilia
- Mucus producing cells produce mucus
- Cover the lining of the trachea
- The dust particles get trapped in the mucus
- The regular (rhythmic) beating movements of cilia push the dust particles to the top of trachea (epiglottis)
Effect of smoking on the lungs
Action of cilia
- Nicotine paralyses cilia
- Cilia no-longer beat
- Pathogens not removed from the blood
- Leads to infection of the respiratory surface
Mucus Production
- Since cilia no-longer function
- Mucus is also not removed
- Therefore more mucus builds up
- And accumulate around the alveoli lining
- Increases the thickness of the alveolar lining
- Gaseous exchange less efficient
- Smoker finds it difficult to breathe
Smoker’s cough
- Is due to the accumulation of tar
Bronchitis
- Accumulation of mucus on the bronchioles
- Caused inflammation of bronchioles
Ventilation
- Ventilation is difficult
- Due to the reduced surface area
- Blockage of tubes
Emphysema
- Smoke particles irritate respiratory surface
- Alveoli damaged/weaken
- Coughing causes destruction of alveoli
- Reduce surface area
- Less gaseous exchange(diffusion)
Causes Lung Cancer
Effect of vigorous exercise on the lungs
- During vigorous exercise more respiration occurs
- Blood running through the brain has a higher carbon dioxide content
- The change in blood composition is detected by the hypothalamus
- The brain sends electrical impulses to the diaphragm and intercostals muscles to contract more
- Action increases the ventilation
- As result breathing rate deepens and increases
- More gaseous exchange occurs
- Carbon dioxide is removed and oxygen is taken in
Excretion
Excretion
- Is the removal of waste products from the body as a result of metabolism.
Kidneys and Excretion
Formation of Urea
- Urea is formed in the liver
- From excess amino acids
- Amino acids are deaminated
- Amino (NH ) group is removed
- Forming ammonia
- Combined with carbon dioxide
- Forming urea which removed by the blood
- Glycogen formed is stored in the liver
Formation of Urine
Ultrafiltration
- Blood enters through the glomerulus (knot of capillaries)
- Blood enters under high pressure
- High pressure is caused by different size lumens of afferent (entering) and efferent (leaving) arterioles
- Liquid part of blood (plasma) is forced through the capillary wall
- Large molecules such as proteins and blood cells are not filtered
- Into bowman’s capsule
- Now it is known as the kidney filtrate
Selective Reabsorption
- Occurs in convoluted tubule
- Glucose, amino acids etc. are reabsorbed
- Into the capillary network (blood)
- The peri-capillary network surrounds the kidney tubule and reabsorb substance from the kidney filtrate
- Against the concentration gradient by the process of active transport
- Therefore requires an input of energy
- Water is reabsorbed depending on the concentration of the blood
Secretion
- Some substance are secreted into the kidney filtrate by the peri-capillary tubule
- Example-water, ions
Urine and Removal
- Once the kidney filtrate reaches the collecting duct it is known as urine
- The urine passes from the CD to the bladder through the ureters
- The urine is stored in the bladder
- And passed out of the body through the urethra, when the sphincter muscles relax
Osomoregulation
- Is the maintenance of osmotic pressure in the blood
When the osmotic pressure is high (Less water in the blood)
- Blood flowing through the brain is concentrated
- The hypothalamus detects the high osmotic pressure in the blood
- As a result stimulates the pituitary gland to release ADH
- ADH travels through the blood to the kidney tubule
- ADH cause the walls of the CD to become more permeable to water
- More water is reabsorbed from the kidney filtrate by the CD
- Urine becomes concentrated
- Lower volume of urine is formed
When the osmotic pressure is less (More water in the blood)
- Blooding flowing through the brain is less concentrated
- The hypothalamus detects the low osmotic pressure in the blood
- As a result suppress the release of ADH
- Less water is reabsorbed
- Urine is becomes dilute
- Greater volume of urine is formed
Kidney Failure
- Kidney failure is result drop in blood pressure
- If both kidney’s are not functioning properly then nitrogenous waste products accumulate in the body
- The accumulation of waste products eventually becomes harmful and may cause death
Kidney Transplant
- Kidney transplant just removes one of the kidney of the patient and replaces it with a donor’s kidney
Requirements
- Healthy donor kidney
- The donor must be of the same blood group as of the patient
- Both the patient and donor must under go surgery
- The donor must have similar kidney tissue as the patient
Rejection
- Rejection is when the body reacts to transplanted tissues (Kidney)
- The rejection is due to the foreign tissues in the body
- As a result the immune system tries to attack and destroy the foreign proteins
- If rejected the transplanted kidney will malfunction
- Immunosupperssvie drugs can betaken to reduce the rejection rate
Advantages of Kidney Transplant
- Less risks of continuous dialysis –can cause infection
- Do not have to be connected machines
- Can leave the hospital
- Do not have to undergo go continuous dialysis
- Less expensive as the patient under surgery once to transplant the kidney but dialysis is continuous life time process
Dialysis
- Removes the waste in the blood
- A dialysis machine consists of a long coiled cellulose tube in a water bath
- The patient’s blood is led from a vein (radial) in the arm and pumped through the cellulose tubing
- The cellulose tube has small pore which allow small molecules to leak into the water bath (Glucose, Urea, Salts)
- Large molecules are unable to pass through the pores (Blood cells, Protein molecules)
- The liquid water bath is watery mixture of salts and sugar in the correct compositions
- This allows substances in the blood to diffuse through the cellulose tube if t is above the concentration gradient
Coordination
Nervous system
- The nervous system is a system containing a network of specialized cells called neuron which carry impulses form the CNS to the Peripheral nervous system and vise versa
Central Nervous System (CNS)
- Brain
- Spinal Cord
Peripheral Nervous System
- All nerves which connect the body to the CNS
Nerves
General structure of nerves
All nerves have a
Cell body- with a nucleus surrounded by a cytoplasm
Dendrites (Dedron)- Branching cytoplasmic fibres
Allows the nerve to make contact with other nerves
Nerve fibre (Axon)- is the longest dendrite
Carries the electrical impulse
Myelin Sheath-insulating effect
Allows the impulse to travel at high speeds
Synaptic nodes- nerve ending which forms synapses with other neuron
Receptors- Detect a change in the environment
Effectors- Produce an effect once an impulse arrives
Types Of Neurons
Sensory Neurone
Direction of Impulse -Carries electrical impulses from receptors to the CNS
Form of Impulse- Sensory impulse
Location of Cell Body- Situated in Dorsal Root/Ganglion, in the spinal cord
Motor Neurone
Direction of Impulse- Carries electrical impulse from CNS to effectors
Form of Impulse- Motor impulse
Location of Cell Body- Situated in Grey Matter in CNS
Rely/Intermediate Neurones
Direction of Impulse-Carries electrical impulse downwards to motor neurones form the CNS
Form of Impulse- Links sensory neurone with motor neurones
(Impulse travels downwards)
Location of Cell Body- Situated in the Grey Matter of the CNS
Synapse
- Synapse is the gap between two neurones
- Electrical impulse arrives at the end of the neurone
- Stimulates the release of neurotransmitter substance (chemical)
- Chemical crosses the gap to the second neurone by diffusion
- Enzyme is released to destroy the chemical in the synapse
Reflex Action
- Reflex action is a rapid involuntary response to a stimulus
- Does not involve the Brain
- Has a protective function
Reflex Arc
Is the nervous path way provided for a reflex action
Advantages of Reflex Action
- Sharp object/heat causes limb to be pulled away
- Automatic response
- No thought involved
- Brain does not receive impulse of action
- Prevents skin from further damage
Spinal Cord
- Spinal cord is the main part of the CNS which is involved with reflex actions
- Spinal cord is divides into two main roots
- Dorsal Root- Sensory Neurones enter the spinal cord
- Ventral Root- Motor Neurones leave the spinal cord
- Most cell bodies are concentrated in the Grey Matter
- Most nerve fibres are concentrated in the White Matter
The Brain
- The Brain expanded part of the spinal cord
- Parts of the brain and their functions
- Medulla-controls involuntary actions such as breathing and heart rate
- Cerebellum- Maintains the balance of the body
- Cerebrum- Deals with acquired skills, memory, intelligence, consciousness, reasoning ability
- The cerebrum consists of two cerebral hemispheres which act as the main command centre of the body
- Hypothalamus-has receptors which detects changes in the blood as it flows through the brain
When the head is jerked backwards violently
- A break occurs in the spinal cord
- The nerve path way between the brain and the body is severed
- No feeling below the break
- And the brain no longer has control of muscles below the break
Endocrine System
- The Endocrine system depends on the action of hormones released into the blood to produce an effect when they reach a target organ
- Hormones are secreted from endocrine glands
- Endocrine glands are ductless glands which release hormones into the blood
Hormone
- A hormone is a chemical substance secreted by endocrine glands, bringing about an effect to a target organ
Types of Hormones
Adrenaline
Site of Production- The Adrenal Gland (Situated on top of the kidney)
Cause of Production-Released in response to
-Fear
-Excitement
-Preparation for fight/flight
Effect- Increases heart beat
- Increase blood pressure
- Increases rate and depth of breathing
- Diverts the flow of blood to muscles
- Triggers the change of glycogen to glucose (Due to increased respiration by cells)
- Pupils Dilate
- More sweating
Anti-diuretic Hormone (ADH)
Site of Production- The Pituitary Gland
Cause if Production-Released in response to low blood water level
Effect-Makes the walls the CD more permeable to water
- More water is reabsorbed in to blood
- Urine more concentrated/ Lower volume of urine produced
Thyroxine
Site of Production-The Thyroid Gland
- Stimulated by the secretion of Thyroid Stimulating Hormone (TSH) by the pituitary gland
Cause of Production- Low metabolism rate
Effect-Increase metabolism rate
- Rapid weight loss
- Rate of respiration increases
- Utilizes growth material
Insulin
Site of Production-The Pancreas (Islets of Langerhans- Beta cells)
Cause of Production- High blood glucose level
Effect- Converts glucose to glycogen
Process- Causes liver cells to uptake more glucose
- As a result glucose is converted to glycogen and stored in the liver
- Lowers the blood glucose level
Glucagon
Site of Production - The Pancreas (Islets of Langerhans-Alpha cells)
Cause of Production-Low blood glucose level
Effect- Coverts glycogen to glucose
Process-Causes liver cells to covert glycogen to glucose
-
And released into the blood
Difference Between Hormonal and Nervous System
Homeostasis
- Is the maintenance of internal environment of the body within narrow limits
Feedback Mechanism
- The feedback mechanism is triggered by too little or too much of an internal factor
- The body becomes aware and restores normal body conditions
Skin
The skin has three main layers
- Epidermis
- Dermis
- Subcutaneous
Temperature Regulation
Over Heating
- Temperature receptors detect rise in temperature
- Nerve transmits impulse to brain
- Causes sweat glands to secrete more sweat
- Passes sweat to the surface of the skin via sweat duct
- Sweat evaporates
- Takes latent heat from skin
- Produces a cooling effect
- Blood vessels dilate
- Increases the flow of blood to the skin
- Hair lies flat
- Effect
- More heat is lost
Over Cooling
- Temperature receptors detect decrease in temperature
- Nerves transmits the impulse to the brain
- Less sweat is produced
- Reduces loss of heat
- Blood vessel constrict
- Reducing the flow of blood to the skin
- Erector muscle contracts
- Hair becomes erect
- Effect
- Prevents the loss of heat
How the skin is adapted against the entry of pathogens
- A layer of dead cells form the epidermis
- Forms a physical barrier against the entry of bacteria, as they cannot penetrate through
- The epidermal cells are continuously worn away and replaced
- The acidic sebum on the surface of the skin, inhibits the bacterial growth
- Receptor in the living layer (dermis) detect changes
- Helps to limit the damage
The Eye
Vision
- Rays enter the transparent cornea and is refracted
- Light rays pass across the aqueous humor into the lens
- Lens focuses the light rays (across the vitreous humor) on to the retina (small upside down image)
- Photoreceptors detect the light rays
- Optic nerve transmits nervous impulse to the brain (cerebrum)
- Brain gives rise to vision
Focusing
Control of Light Intensity
Bright Light Dim Light
Radial muscles (in iris) relax Radial muscles (in iris) contract
Circular muscles (in iris) contract Circular muscles (in iris) relax
Iris becomes larger Iris becomes smaller
Pupil becomes smaller Pupil becomes larger
Allows less light to enter the eye Allows more light to enter the eye
Stereoscopic Vision
- Each eye forms a separate image on the retina
- (Retina is stimulated twice)
- Brain combines and interprets the two separate images
- Forming one clear image
Advantages of stereoscopic vision
- Allows the brain to form 3D-images
- The relative positions allows the brain to judge the speed or distance
Sight Defects
Long (Far) Sightedness Short (Near) Sightedness
Is corrected by a convex lens Is corrected by a concave lens
Photoreceptors
Ear
Path of Sound Vibrations in the Ear
- Sound waves in air are directed by the oricle into the middle ear via auditory canal
- Sound vibrations strike on the ear drum and cause an amplification of sound vibrations
- Ossicles transfer the vibrations from the ear drum to the oval window across the air filled cavity
- Vibrations are transmitted to the inner ear across the perilymph fluid
- By movements (flucuations) of the perilymph fluid (caused by vibration)
- The organs of corti in the cochlea are stimulated
- Converts sound vibrations to the electrical impulses
- Sensory impulses are carried by the auditory nerve to the brain (cerebrum)
Reproductive System
Fertilization
- Is the fusion of male and female gametes
Process
- Sperms are ejaculated during sexual intercourse (copulation)
- Active sperms meet the ovum in the oviduct
- Enzymes are released from the acrosome of the sperms to penetrate the ovum
- Eventually one sperm penetrates the ovum releasing only the nucleus into the ovum
- The protein coat of the ovum thickness preventing entry of other sperms
- All other sperms die in the uterus
- The sperm nucleus fuses with the nucleus of the ovum to form a zygote
- The fertilized egg cell is passed along the oviduct (cilia) to the uterus
- The embryo implants in the uterus (uterine lining)
Development
Structure of the Placenta
- For implantation to take place chronic villi grow into the uterine wall to implant the embryo
- Eventually forms a disc of tissues which is attached to the uterine lining
- Has blood spaces (formed by break down of thickened capillaries) which are rich in blood supply
- Interlocks the maternal and fetal tissues
- Large surface area is provided by the chronic villi
- Umbilical cord attaches the fetus to the placenta
- Umbilical vein carries blood away from the fetus
- Umbilical artery carries blood to the fetus
- Thin barrier between blood spaces
- Maintains a good diffusion gradient
Function of the Placenta
- Prevent direct contact with the maternal and fetal blood as the may be of the different blood groups
- Protects the fetus (fetal tissues) from the high blood pressure of the maternal blood
- Allows the fetus to remove waste products and obtain nutrients under a concentration gradient
- Transfers antibodies
- Prevents harmful substances in maternal blood from transferring to the fetus
- Produces progesterone
- Movement of Substances through the placenta
- Materials from maternal blood diffuses across the placenta down a diffusion gradient
- Between fetal and maternal blood
- Substances passed from and to fetal blood via umbilical cord
Function of Progesterone During Pregnancy
-First three months produced by the Corpus Luteum
-Last six months produced by the placenta
- Prevents the break down of the uterine lining
- Prevents miscarriages(abortion)
- Helps further thickening uterine lining and develop of blood vessels in the uterine lining
- Stimulates placenta growth’
- Present ovulation (suppress FSH secretion)
- Prevents uterus from contracting
Menstrual Cycle
- Follicle Stimulating Hormone (FSH) secreted by the pituitary gland, stimulates the maturation of the follicle (Graffian Follicle)
- As follicle develop oestrogen levels rise casing the uterine lining to thicken and more blood vessels to develop
- (Action prepares the uterus for early implantation)
- Rise in oestrogen levels cause the pituitary of produces Lutinzing Hormone (LH) and suppress the FSH levels
- LH stimulates ovulation
- Release of the egg into the fallopian tube (Ovulation) occurs on day 14 of the menstrual cycle
-
Old follicle is now referred to as the Corpus Luteum
- Corpus Luteum produces progesterone
- Causes endometrium to become vascular
-
If the ovum s not fertilized progesterone levels fall
- Causes the lining of the uterus to break down
- Blood vessels break down
- Mesuration
- Loss of blood through the cervix
- Progesterone levels remain high
- Uterine lining does not break down
- Endomentruim thickness further
- Allows development of fetus (no more ovulation)
Amnion
- Has amniotic fluid which prevents
- Pressure damage (transmission of pressure to the fetus)
- Reduces friction
- Acts as a shock absorber
Birth
- Gestation period is the duration of time which the fetus remains in the uterus from the time of fertilization
- Child Birth
- Strong muscular contractions in the uterus are caused by changes in hormonal levels
- During labor contraction becomes more frequent and intense
- Amniotic membrane ruptures and releases amniotic fluid
- The cervix dilates allowing the baby to pass into the birth canal and eventually out
- After birth the placenta and uterus linings discharge
- And the umbilical cord is tied and cut
Lactation
- Is the secretion and ejaculation of milk from the memory glands
- Lactation is controlled by the action two hormones secreted by the pituitary gland
- Prolactin- stimulates secretion of milk
- Oxytosin –stimulates ejaculation of milk
- Hypothalamus maybe be stimulated emotional example at the site of the baby crying
- And the hypothalamus is also triggered by the action of suckling
Advantages of Lactation
From the child’s side
- Helps build the mother child bond
- Act of suckling on the breast promotes development of the jaw and facial muscles and teeth encouraging speech development.
- Less chance of allergic reactions
- The composition of breast milk changes with the development and growth of the infant
- Helps to cleanse the baby’s bowels
- Provides antibodies (passive immunity)
From the mother’s side
- Prevent ovulation
- Reduces the risk of ovarian and breast cancers
- Utilizes that fat accumulated during pregnancy
Postmatal Development Stages
Changes which occur soon after birth (Infancy)
- Lungs start to function
- Baby ventilates and begins to breathe
- Must learn to control body temperature (regulate heat loss)
- Must begin to suckle from milk to obtain nutrients (nutrients are no longer available via placenta)
- Digestive system must function (peristalsis must occur)
- Begins to respond to stimuli
- Begins to get rid of waste (excretion)
- Liver starts functioning
Between the ages of 0 and 3 years (Childhood)
- Rapid growth period
- Teeth appear
- Begins to eat solid food(not just milk diet)
- Learns to balance body weight and start walking
- Rapid growth of limbs
- Development of communication skills (speech)
- Greater aware of surroundings
Between the ages of 10 and 15 years (Adolescence)
- Onset of puberty
- Rapid growth spurt
- Increase in hormone levels
- Increase in body size
- Increased awareness in opposite sex
- Gamete production
- Appearance of secondary sexual characteristics
Females
- Ovaries become active
- Hormone level of oestrogen and progesterone increase
- Begins to ovulate onset of menstrual cycle
- Pituitary becomes active secrete FSH and LH
- Oestrogen stimulates secondary sexual characteristics
- Growth of hair in the pubic region
Males
- Testes becomes active
- Produces sperms
- Testis produces testosterone which stimulate secondary sexual characteristics
- Growth of hair in the pubic region
- Breaking (deepening) of voice
- Increase facial hair
- Aggressive behavior
Between the age of 18 to 50 years (Adulthood)
- Remains physically and physiologically unchanged for many years
- Environmental and heredity factors weakens the body actions
- Hair grows grey
- Secretion of testosterone in male is suppressed
- Female experience menopause
Between the age of 50 to death (Senesces)
- Body functions slowly becomes weak
- Body becomes less capable to cope with demands placed on it by the individual and the environment
Contraception
Contraception is preventing unwanted pregnancies
Contraception methods
Barrier Methods
- Effect-Prevents sperms from reaching the ovum
- Reduces chances of STD’s
- Failure rate- High, due to displacement during intercourse
- Reliable and safe method of contraception
- Needs to be put before intercourse
Female
- Cervical caps fitted against the end of the uterus (cervix)
- Diaphragm fitted into the vagina
- Femidoms lines the vagina
- Used with spermicidal which destroy any sperms which come in contact
Male
- Condom-fitted against the penis
Physical Contraception
- Physical preventing the penis from coming into contact with the vagina
- Rhythm method prevent having sexual intercourse during the time after ovulation
Hormonal Methods
- Contains hormones-progestin (progesterone like hormone)
- Effect-Prevents ovulation
- Inhibits the secretion of FSH (follicle does not mature) and LH from the pituitary
- Tricks the pituitary always assuming the individual is pregnant (high levels progesterone)
- No fertilization occurs
Contraceptive pill
- Could sometimes forget to take the pill
- Health issues arise
Hormonal injection
Implants (Norplant Implant)
- Silicon (six) rods a implanted into the body over a period of time they
release progestin
Sterilization
- Involves undergoing an operation (under medical circumstances)
- After sterilization individual becomes infertile
- Reliable method
- Cannot be reversed
- Carries risk of infection
Males (Vasectomy)
- Sperm duct is cut and tied
- Prevents sperms from leaving
Females (Tuber Ligation)
- Oviduct is cut and tied
- Prevents the release of ova
Movement
Muscles
- Cardiac
- Skeletal
- Smooth
Functions of the Skeletal System
- Protection of delicate organs (internal) form external damage
- Production of red blood cells (ends of bones marrows produced red blood cells)
- Movement- Allows muscle attachment to provide movement (Bones act as levers and produces movement when muscle pulls on it)
- Support- Rigid skeleton maintains familiar shape and lifts the body off the ground during rapid movement
Types of Joints (where two joints meet)
-
Immovable joints- Example: Sutures ( In the skull)
-
Partially joints- Example: Joints formed between intra-vertebral discs (Between vertebrae of the spinal cord)
-
Synovial joints (joints which have a synovial membrane )
- Ball and Socket (universal joint)
- Freely movable (360 )/ All around movement
- 3 plane movement
- Partially movable (180 )
- 1 plane movement
A Typical Synovial Joint Structure
- Bone are shaped to fit each other
- Cartilage present between ends of bones (friction-free movement)
- Synovial membrane secretes synovial fluid (acts as a lubricant)
- Tendon attaches (runs across joint) muscle to bone (muscle move joint by transferring the pull)
- Ligaments hold bones together at a joint (prevent dislocation)
Cartilage
- Cushions the ends of bones
- Reduces friction between ends of bones at a joint (slippery surface)
If cartilage is damaged or wears away
- Smooth surface becomes rough
- Bones rub together and friction increases (grating of bones)
- Pain of movement
Synovial fluid
- Secreted by the synovial membrane
- Acts as a lubricant
- Reduces the friction between cartilage
- Shock absorber
Effects of extra secretion of synovial fluid
- Extra synovial fluid creates pressure
- Bones at a synovial joint swell
- Pain and difficulty of movement
Tendons Ligament _
Inelastic (very strong) Elastic
White fibres Yellow fibres
Links muscle to bone Links bone to bone
Prevents dislocation of bones at a joint
If a tendon is ripped
- Tendons link muscle to bone
- And transmits pull
- If torn pull is not transmitted
- Therefore no movement of joints
Antagonistic Muscles
- Occur in pairs one muscle moves the bone in one direction and the other muscle moves it in the opposite direction
How the structure of a long bone helps to carry out its function
- The long bone is made of calcium slats
- Makes it hard and rigid
- Lifts the body of the ground
- Hard compact bone along the shaft
- Resists compression
- Protects bone marrow in the cavity
- Bone marrow is present in the cavity
- Ridges for attachment of muscles
- Cartilage
- Shafts at the ends of the bones
- Allows growth until adulthood
- For articulation of bones at a joint
Microorganisms
Microorganisms
- Bacteria
- Virus
- Fungi
- Protoctists
Bacteria
Structure
- Has no nucleus/Just a coiled strand of genetic material
- Has circular strands of DNA (plasmid) in the cytoplasm
- Presence of a cell wall and cell membrane
- Has no membrane bound organelles
- Some have a slime layer which is not harmful/ Some have a capsule which is harmful
- Pilli short attachment on the surface/ Flagellum long attachment on the surface fro locomotion
- Some have endospores which are resistant to high temperatures
Type of Nutrition
Saprophyte
- Feeds on dead organic matter
- Secretes extra-cellular enzymes to digest food
- Absorbs products of digestion
- Brings about decay
- Recycle nutrients
- Involved on the nitrogen an carbon cycle
Parasitic
- Obtains food from living on host organisms
- Enters cells of the host
- Uses up cell nutrients
- Causes damage to host by releasing toxins leading to the
development of a disease
Uses of Bacteria
- Decomposition
- Food production
- Example:- Cheese/Yogurt/Soya Sauce
- Synthesis of vitamins
- Recycling: involved in the nitrogen and carbon cycle and sewage treatment
- Biotechnology: - Genetic Modification
Virus
Structure
- Has a capsid/ a protein coat
- The protein coat is made up single protein units called a capsomere
- Single nucleic strand of DAN/RNA (genetic material)
- Contains no nucleus and cell organelles
Reproduction of Viruses
- Reproduce only inside living host cells
- Virus attaches to the cell surface membrane of the host cell
- And penetrates the cell membrane
- Virus injects DNA/RNA thread into the host
- Capsule is left outside
- The nucleic tread from the virus joins with DNA of the host cell
- Causes replication or viral genetic material
- Capsid forms around the genetic material (by using materials from the cell- Example Cell membrane)
- New viruses formed
- Cell bursts and releases many viruses
Type of Nutrition
Parasitic
- Obtains food from living on host organisms
- Enters cells of the host
- Uses up cell nutrients
Fungi
Structure
- Mass of branching hair like threads called hyphae
- Mass of hair called mycelium
- Hyphae not dived into cells
- Cell wall of hyphae made of chitin
- Unicellular
- Contains many nuclei
Reproduction of Fungi
- Fungi reproduce by releasing spores to the surrounds which eventually grow into an individual fungus
Use of Fungi
- Example-:Streptomycin from Stretomyces /Penicillin from Penicillum
-
Example:- Mushroom/Ruffles
- Involved in food production
-
Example:- Flavoring of Cheese/ Production Bread (respiring of yeast makes the dough rise)
- Production of alcohol by fermentation
-
Example:- Beer and Wine by the action if yeast
- Decomposition of dead organic matter –decomposer (see below for further description)
Diseases
Before a disease can develop
- A person must be susceptible (depends on the state of the immune system-favorable conditions are provided)
- The causative organism must be present in sufficient numbers
- The causative organism must be virulent (potent-strong)
Development of a disease
Infection Period
- The time period in which the causative organism enters the body
Incubation Period
Period in which
- Causative organism reproduces (large population)
- And release waste products as they metabolize
-
Release of waste products cause the appearance of signs and symptoms of the disease
Infective Period
- The period in which antigens pf the bacteria stimulate the immune system
- Antibody formation
- Protection provided by white blood cells
- During this period of patient has a chance of spreading the disease to others (Isolation of the infected)
Recovery stage
- Antibodies inhibit bacterial action (release of toxins)
- Antibodies destroy toxins
- Symptoms subside
Action of Antibiotics
- Antibiotics is a chemical substance that kills or prevents bacteria from reproducing
- Certain fungi secrete antibiotics when competing with bacteria for food
- Antibiotics is a drug produced by certain fungi used to destroy bacteria but does not harm body cells and manages to quickly lower the bacterial population
Growing Bacteria
- Place the agar medium in a sterilized Petri dish
- Dip the metal loop in the culture medium (bacteria chosen to grow)
- Use metal loop to streak agar
- Incubate at suitable temperature for a few days (minimum 24 hours)
- Observe plates for bacterial growth
- Satin and identify bacteria under microscope
Endemic
-
Disease always present at low levels in a population
Epidemic
-
Sudden outbreak of a disease above the normal level in population
Disease caused by Bacteria
Typhoid
Causative organism
- Salmonella Typhi (Bacillus)
Transmission
- By vector (housefly or cockroaches)
- Feeding habits- moves from one food to another
- Vector transmits pathogens to food
- Housefly lands on faeces (contaminated)
- Has hairy and sticky legs traps and carries pathogens
- Has a proboscis (mouth piece) which secretes saliva containing ingested pathogens
- Saliva squirted onto the food
- Contaminates the food with the pathogens
- Human carries transmit the pathogen due to lack of personal hygiene
- Pathogen carried in human faeces
- Pathogen transferred to hands
- Hands are not washed after using toilets
- Transferred to food or utensils
- By contaminated food and water with the pathogens
Prevention and Control
- Cover food (wrap all food)
- Store food in refrigerators
- Keep plate and cups away from flies
- Use of insecticides
- Fly traps
- Implementing 100 % sanitation and personal hygiene
- Sterile food working surfaces
- Destroy breeding sites
- Remove trash from kitchen/Cover dustbins
- Proper disposal of refuse
- roper disposal of faeces
- Access to safe water supply (water treatment)
Tuberculosis (TB)
Causative organism
- Mycobacterium Tuberculosis
Transmission
- Airborne droplet infection
- Through untreated milk
Prevention and Control
- Testing milk from cattle/ Do not drink milk form infected cattle/Pasteurization of milk
- No spitting
- Prevent exchange of hankies
- BCG test to see if infected
Treatment of infected by vaccination
- Good ventilation
- Isolation of the infected
- Avoid overcrowded areas
Treatment
- Antibiotics -:Streptomycin
- Careful nursing
- Good ventilation
- Improved diet (high in protein)
Gonorrhea
Causative organism
Transmission
- Sexually transmitted
- Mother to fetus via placenta
Prevention and Control
- Do not promiscuous/ Limit to one sexual partner/Do not make use of prostitutes
- Screen for those who are infected
- Use sterile needles and syringes
- Have safe sex/Uses of condoms and femidoms (covers the lining of the vagina and penis)
- Prevent exchange of body fluids
- Education about sexually transmitted diseases
- Tracing and treating the infected (reporting the symptoms)
Symptoms
- Pain and discharge of puss from the urethra (leads to blockage and sterility)
- Bacterium can invade the child’s eyes during birth and causes blindness
Treatment
- Course of antibiotics, penicillin and is most effective when taken early on
Diseases caused by Viruses
Common Cold
Causative organism
Transmission
- Direct contact with the infected
- Air borne or droplet infection
- From coughing and sneezing
Prevention and Control
- Isolation of the infected
- Avoid overcrowded areas /Good Ventilation
- Do not use the same Hankies
- Careful nursing of the infected
Treatment
- Cold virus mutates (changes) frequently
Acquired Human Immune Deficiency Syndrome (AIDS)
Causative organism
- Human Immunodeficiency Virus (HIV)
Transmission
- Sexually transmitted (no epidermal lining of the penis and vagina)
- Mother to fetus via placenta
- Direct contact with blood
- Contaminated blood transfusion
- Using contaminated needles any syringes
Prevention and Control
- Do not promiscuous/ Limit to one sexual partner/Do not make use of prostitutes
- Screen for those who are infected
- Use sterile needles and syringes
- Have safe sex/Uses of condoms and femidoms
- Prevent exchange of body fluids /No contact made at copulation
- Education of STD’s
Treatment
- NONE
- HIV mutates frequently
(Changes its protein coat by the use of the cell membrane of it host cells so it cannot be identified by white blood cells)
Poliomyelitis (polio)
Causative organisms
Transmission
- Through feces
- Direct contact with the infected
- Air borne or droplet infection
- From coughing and sneezing
Prevention and Control
- Avoid overcrowded areas /Good ventilation
- Isolate patient
- Vaccination
- Careful nursing (Hospital care)
Treatment
Diseases caused by Fungi
Athlete’s Foot
Causative organism
- Tinea Ring Worm (Parasite)
Grows in moist conditions on the surface if the skin between toes
How it obtains its food
- Parasite which lives on the surface of the skin between toes.
- Fungus secretes extra-cellular enzymes which digest skin cells for food
- Dampness is necessary to absorb products of digested skin into hype via diffusion
Transmission
- Direct transmission (no vector involved) from person to person
- Floors of changing rooms and other damp places
- Sharing contaminated towels socks or shoes
- Skin shed form feet of infected person contains organism’s hyphae and is picked up by uninfected person and the person gets the disease
Prevention and Control
- Wear slippers in changing rooms
- Disinfect floors regularly
- Treatment of the infected
- Stop suffers by implementing well ventilated foot wear inhibit growth
- Avoid cross infection- Do not share same towel/shoes/socks
- Carefully dry in between toes
- Avoid walking barefoot
Treatment
- Apply fungicidal cream to infected area
-
Allow ventilation in between toes to inhibit growth
Thrush /Candidiasis
Causative organism
- Single Celled Fungus (Parasitic-invades epithelial cells and causes white patches)
Transmission
- Spread by contaminated water
- Un-sterilized equipment used for feeding
- Sexually transmitted
- Prevention and Control
- Proper sterilization of (mouth) equipment
- Chlorinating or boiling water
- Wearing condoms
- Safe sex
- Treatment of the infected
- Personal hygiene
Treatment
- Application of antifungal cream
Other Parasitic Diseases
Malaria
Causative Organism
- Plasmodium (parasitic protozoa)
Vector
- Anopheline (Anopheles) mosquito
Adaptation of anopheline mosquito
- Adult mosquito can fly from host to host
- Mouth parts are sharp and are able to pierce and penetrate the skin to reach blood
- Injects saliva containing anticoagulant to prevent the blood from clotting
- Diet involving sucking blood allows the parasite to be transferred during a blood meal
- Breed in large numbers and so the parasite can be transmitted easily
Life Cycle
- Female adult and so sucks blood of the infected host
- Ingests the parasite present in the blood of the host
- Parasite undergoes maturation in the salivary glands of the mosquito
- Plasmodium spreads during a blood meal
- The mature plasmodium is injected into the blood of unaffected host
- Plasmodium under goes maturation in the liver cells
- Later rupture the liver cells and enter the blood
- And again blood is taken in by female mosquito
Prevention and Control
Break the life cycle of vector (Measures against vector)
- Drain swamps
- Increase the rate of flow of collected water in an area
- Removing tins etc. to prevent water from collecting
- Mosquitoes lay eggs in water so it prevents mosquito from using as its breeding grounds
- Spread oil on surfaces of water
- Forms a barrier for oxygen since larvae can not obtain oxygen its sinks down
- Introduce biological methods by introducing insectivorous fish which feed on larvae
- Spray insecticides (kill the adult mosquito)
Self protection
- Sleep under mosquito nets
- Cover body from dawn to dusk (mosquitoes are active at this time) to reduce the biting surface area
- Spray or apply repellent creams
- So that adult mosquito can not attack and reach the skin
- Take anti- malarial drugs to prevent parasite from reproducing in humans
Schistosomiasis
Causative organism
Life Cycle
- Adults releases eggs in humans
- Schistosoma eggs present in faeces and urine
- When excreted by humans into water bodies the eggs develop and hatch releasing a larva
- Larva develops into ciliated miracidium
- Seeks into secondary intermediate snail host
- Develops in the snail host to redia
- Final development in the snail into cercaria (second type of larva)
- Cercaria released into water
- Cercaria penetrates human skin and enters the definite host
Prevention and Control
- Good sanitation (usage of clean water)
- Building bridges over water
- Wearing boots and other methods of prevention to prevent the secondary larva from penetrating human skin
- Drain marshes destroys hatching sites of eggs
- Increase the speed of slow flowing water
- Use of molluscicdes to destroy secondary larvae
-
Destroy secondary host by introducing biological control methods (Example- Snail eating ducks)
Food and Sanitation Disposal
Biological Methods of Preservation
Canning
Food is heated to destroy bacteria
Put and sealed in an air tight can
Prevents further entry of bacteria
Dehydration
Removes water from the food source
Bacteria become inactive
And is unable to digest the food or reproduce
Freezing
Reduces the temperature (-12 c or below)
Enzymes are inactive
Bacteria are unable to reproduce
Salting/ Syrup
Raises the osmotic potential of the food source
Due to the steep concentration gradient water diffuses out of the bacteria
Removes water from bacteria (dehydrates bacteria)
Bacteria becomes inactive
Smoking
Food is suspended for some time over wood smoke
Chemicals in smoke destroy bacteria
Prickling
Involves the change in pH
Vinegar is acidic and it lowers the pH
Unsuitable for bacterial activity
Why food must be eaten after cooked?
Thorough cooking destroys bacteria present
And must be eaten before recontamination occurs by files and air
Sewage treatment
1. Screen/Grid
Removes large solid objects
In the grid, paddles breakdown large organic matter to small particles
2. Grit Chamber
Slows the flow rate
Large particles from the sewage fall and settle at the bottom
3. Sedimentation Tank
Effluent removed from sludge (separates liquid from solid)
Allows sedimentation of the solid particles
Activated sludge Process
4. Oxidation Tank
- Oxygen is passed to airate the tank
- Oxygen is needed for aerobic bacteria to become active
- Bacteria digests harmful organic material in effluent (liquid)
- Effluent is now free of harmful material
5. Sludge Digester
- Remaining sludge reaches the sludge digester
- Anaerobic bacteria digest organic matter
- As a result produces heat which kills pathogens and speeds up the reaction
- As a result methane is produced
- Methane can be used for fertilizers and fuel
Trickling Method
4. Sprinkler/Trickling filter/Pre Colating
- Liquid drips on pebbles (clinker)
- Oxygen collects and airates the tank
- Pebbles are coated with slime from bacteria and other microbes which are anaerobic
- They feed organic materials in sewage
- As a result heat is produced which kills pathogens in liquid effluent and makes it safe
Purification of Water
1. Grids/strainer remove large objects
2. Water is sent at slow rate through the inlet
3. Slow Sand Filter
- Bacteria fungi and other microorganisms reproduce and a jelly which is supported by the sand
- A food chain forms and the microorganisms in the water competes with the bacteria from the jelly as the water passes
OR
3. Rapid Sand Filter
- Alum is added to coagulate as it forms a thin jelly which traps various kinds of particles
- The water and the jelly are passed under pressure through large tank
- The sand supports the jelly while the water passes rapidly through
Chlorination
- When bubbled through water forms a weak acid
- Which inhibits the growth of microorganisms
- And kills microorganisms already present
- Water is then kept in large enclosed reservoirs so that no more organisms can enter
- Delivered via closed pipes to taps
Pit Latrine
- Pit must be dug to allow build up during decay
- The pit is lined with concrete to prevents seepage and entry by burrowing animals (Example: - Rats)
- The floor is made out of concrete this allows hygienic cleaning
- Cover for the pit, the cover prevents flies from landing on sewage and prevents smell from escaping
- Mesh cover the pit to prevent files from entering to reduce the spread of pathogens
Why it is important to consider the location of a pit latrine ?
The pit latrine must be situated away from uphill water supply and sited away from houses
To reduce flies and other vectors transporting pathogens which might cause diseases to the house
Must be built at a distance from the house due to the bad smell