The bulbourethral glands are responsible for the neutralisation of the acidic urine that may remain in the urethra. When the gland secretion mixes with sperm then seminal fluid is formed (sperm).
The penis deposits semen into the vagina during sexual intercourse.
The prostate gland is under the bladder and surrounds the top of the urethra. The secretions of the prostate gland neutralise the acidity of the vaginal fluids which allows sperm to move through the vagina to the uterus to fertilise an egg.
The Musculo-Skeletal System.
The musculo- skeletal system is the bones of the human skeleton and the striated muscles that are attached.
Skeletal System.
There are 206 bones in the human skeleton, each of these bones is used to support or provide movement. The human skeleton provides protection to the interior organs, such as brain, heart, and lungs but within the bones blood cells are made and useful materials can be stored.
The human skeleton is the support mechanism of the body, it forms the framework. The axial skeleton is the skull, vertebral spine, ribs and sternum which are in the midline of the body. The appendicular skeleton is the limb bones and the attachments to these.
Where bones meet together, there are joints; joints can be fixed, freely moveable or only slightly moveable.
Joints that are freely movable are synovial joints; these types of joints are complex and found in places that require a lot of movement, such as the fingers, toes, hip, knees, elbows or shoulders.
Joints that are only partially moveable are found in places like the vertebra and the pelvis. There is a layer of cartilage which joins the two connecting bones; cartilage is a fairly rigid substance which means that the joint has only limited movement.
Joins that are fixed are found in places like the skull. Fibrous tissue connects the bones causing an immovable structure.
Compact and spongy are two different types of bone tissue which differ in density. Compact bone tissue makes up the exterior of the bone because it is hard and dense, whereas spongy bone tissue is found inside the compact bone tissue. Spongy tissue is porous so it isn’t strong enough to offer protection like the compact tissue.
Muscular System
The muscular system provides the human body with movement, this is by muscles contracting or relaxing.
There are several different types of muscles, these are:
- Cardiac Muscles – this type of muscle can only be found in your heart.
- Smooth Muscles – these are located in the hollow walls of organs.
- Skeletal Muscles – provides movement, generates heat, maintains posture and stabilises joints.
Cardiac Muscles are muscles of the heart. The atria and ventricles are the heart walls which are cardiac muscles, they contain striated fibres. The cardiac muscles are involuntary because we cannot control them.
“Your heart is made of cardiac muscle. This type of muscle only exists in your heart. Unlike other types of muscle, cardiac muscle never gets tired. It works automatically and constantly without ever pausing to rest. Cardiac muscle contracts to squeeze blood out of your heart, and relaxes to fill your heart with blood.” (BBC UK. Science human body and mind: muscles – skeletal, smooth and cardiac [online] BBC UK. Available from: [26/11/10]).
Smooth muscles are blood cells, internal organs and glands; they are involuntary muscles and nonstraited.
Smooth muscles are found within the walls of digestive tract organs, they cause contractions that help force food digestion and transport.
“Smooth muscle is found in the walls of hollow organs like your intestines and stomach. They work automatically without you being aware of them. Smooth muscles are involved in many 'housekeeping' functions of the body. The muscular walls of your intestines contract to push food through your body. Muscles in your bladder wall contract to expel urine from your body. Smooth muscles in a woman's uterus (or womb) help to push babies out of the body during childbirth. The pupillary sphincter muscle in your eye is a smooth muscle that shrinks the size of your pupil.”(BBC UK. Science human body and mind: muscles – skeletal, smooth and cardiac [online] BBC UK. Available from: [26/11/10]).
Skeletal muscles have ordered groups of fibres
Non-striated muscles (smooth): the fibres are wider in the centre and smaller towards the ends. Non-striated muscles are layered.
“The tissue most commonly thought of as muscle is skeletal muscle. Skeletal muscles cover your skeleton, giving your body its shape. They are attached to your skeleton by strong, springy tendons or are directly connected to rough patches of bone. Skeletal muscles are under voluntary control, which means you consciously control what they do.” (BBC UK. Science human body and mind: muscles – skeletal, smooth and cardiac [online] BBC UK. Available from: [26/11/10]).
Striated muscles are when the muscle fibres interlink, cross-over, causing this type of muscle to be strong.
The Lymphatic and Immune Systems.
The Immune system’s main function is to protect the human body from microorganisms that can invade the body and cause harm.
The immune system’s structure is scattered throughout the body and made up of cells, tissues and proteins; although this system is not classed a major system of the body, it is a major part of the body’s defence.
The immune systems main components are:
- Lymphatic vessels and lymph nodes
- Thymus gland
- Spleen
- Tonsils
- Adenoids
- White blood cells: - lymphocytes, granulocytes, monocytes
- Lymphoid tissue: peyers patches found in the intestine.
All of the above components are majorly involved in protecting the body from harm. White blood cells are the body’s natural defence system in fighting infection.
As figure 12 shows there are many exterior microorganisms that can potentially cause harm to the body. The immune system can generally become immune to certain types of infections such as chicken pox but there are many microorganisms that the human body cannot become immune too such as HIV, MRSA, Tuberculosis and Sexually transmitted infections.
Immunisation vaccinations can be given to help the immune system to be able to defend the body in case of invasion. The measles, mumps and rubella vaccination (MMR) prepare the immune system by injecting a small dose of the virus into the body so that the white blood cells can create anti-bodies to destroy the foreign material; the immune system creates anti-bodies to fight off infection and then remembers the anti-bodies for if and when the micro-organism attacks the body again.
The lymphatic system: In potential sources of infection that are associated with the immune system such as the tonsils, adenoids, spleen and thymus gland are specialised areas in which lymphoid tissue occurs.
Lymphatic capillaries are located between body cells in the tissue spaces. The lymphatic capillaries join to lymphatic vessels and then ducts such as the thoracic duct.
The ducts take the collection of fluid that is composed within the vessels back to blood circulation. Every lymphatic vessel penetrates through one or more lymph nodes, there are hundreds of lymph nodes scattered throughout the body.
Lymph nodes found in the neck/head are known are cervical lymph nodes. Axillary lymph nodes are located near the heart. There are lymph nodes in the mammary gland as well as the pelvis and lower limb.
The Cardiovascular System:
The cardiovascular system consists of:
- The heart
- Arteries, veins and capillaries
- Blood.
The heart is found in the thorax cavity between the lungs. The rib cage protects the lungs and heart from exterior damage. There is a thin film of fluid inside a tough membrane which prevents friction between the organs and the rib cage, this is called the Pericardium.
The heart is slightly larger than a clenched fist in an adult – it is muscular pump. The primary function of the heart is to continuously pump blood around the body to cells – the blood is forced around the body through a network of blood vessels, made up of arteries, veins and capillaries.
Blood carries oxygen around the body as well as hormones, nutrients, salts, enzymes, and heat but also removes waste products such as carbon dioxide, water and urea.
“The heart is a double pump, each side consisting of an upper chamber (the atrium) and a lower chamber (the ventricle). The right side of the heart pumps deoxygenated blood from the veins to the lungs for oxygenation. The left side pumps oxygenated blood from the lungs to the body and the two sides are completely separated by a septum. The blood passes twice through the heart in any one cycle and this is often termed double circulation.” (B. Stretch and M. Whitehouse, 2007, Page: 224)
The heart consists of four chambers, the left Atrium, the right Atrium, the left Ventricle and the right Ventricle; each of these chambers has a major blood vessel entering or leaving it. “Veins enter the atria and arteries leave the ventricles” (B. Stretch and M. Whitehouse, 2007, Page: 225) Veins take blood to the heart whilst Arteries take blood away from the heart.
The two types of circulation in connection with the heart are the pulmonary circulation (to the lungs and back) and the systemic circulation (around the body).
In pulmonary circulation, the deoxygenated blood is taken to the lungs via the Pulmonary artery which leaves the right ventricle. When oxygenated blood returns it enters through the left atrium.
All organs within the body have arteries and venous supply which deliver and collect blood that supplies the organ tissues.
Systemic circulation which supplies the blood around the body uses all the blood vessels that are not involved in pulmonary circulation.
“Oxygen makes up about a fifth of the atmosphere. You breathe air through your mouth and nose and it travels to your lungs. Oxygen from the air is absorbed into your bloodstream through your lungs. Your heart then pumps oxygen-rich ('oxygenated') blood through a network of blood vessels - the arteries - to tissues including your organs, muscles and nerves, all around your body.
When blood reaches your tissues, through the capillaries, it releases oxygen, which is used by cells to produce energy. In exchange, these cells release waste products, such as carbon dioxide and water, which are absorbed and carried away by your blood.
The used (or 'deoxygenated') blood then travels along your veins and back towards your heart. Your heart pumps the deoxygenated back to your lungs, where fresh oxygen is absorbed, and the cycle starts once again.” (BUPA UK. (May 2009) Cardiovascular System. [Online] Bupa UK. Available from: [26th November 2010]0.
In reference to Figure 14, you can see that the Aorta is main artery and leaves the left ventricle. The main vein, Vena Cava, brings blood from the body back to the heart and enters through the right atrium
The Vena Cava divides into the superior and inferior vena cava; the superior brings blood from the head and neck whereas the inferior vena cava brings blood from the rest of the body.
It is extremely important that blood flow within the heart only happens in one direction which is why there are valves at specific points; between the atria and ventricles there are two sets of valves – the bicuspid valves are on the left and tricuspid valves are on the right. The bicuspid valve has two cusps and the tricuspid valve has three cusps. Cusps are thin flaps which prevents blood from flowing backwards. Attached to the cusps are papillary muscles which tense as the ventricles contract to let blood flow through.
The Pulmonary Artery and the Aorta’s valves are known as semi-lunar valves.
Cardiac muscle is myogenic which means that the contractions are performed rhythmically without a nerve supply. The atrial muscle and the ventricular muscle beat at different paces.
The atria muscle walls are thinner in comparison that the muscular walls of the ventricles; this is because the ventricles have to work harder in order to pump oxygenated blood through the heart. The right ventricle only has to deliver blood to the lungs so this ventricle is thinner than the left because the left ventricle has to pump oxygenated blood round the entire body.
The cardiac cycle can be divided into 6 processes:
- Atria contract to force blood into the ventricles.
- Blood pressure increases in the ventricles forcing the atrio-ventricular valves to close.
- The muscular walls of the ventricles begin to contract forcing the semi-lunar valves to open.
- The aorta and pulmonary artery begin to expand.
- The muscles in the ventricles relax and the blood momentarily flows backwards and lodges in the semi-lunar valves forcing them to shut.
- The atrio-ventricular valves open are forced open by the blood flow. The atria contracts as the ventricles begin to refill. So the cycle starts again.
Capillaries
Capillaries walls are only singled- celled, they are simple squamous epithelium. They are supplied by blood from the arterioles. Body cells rely on the nutrients and oxygen that are supplied by capillaries.
Venules and Veins
Capillaries supply venules which lead into veins. Venules are much smaller veins. Blood pressure is low in veins and venules because they carry deoxygenated blood.
Blood
Blood cells, Erythrocytes, contain haemoglobin which is extremely important for respiration.
Haemoglobin is a protein that contains iron. Haemoglobin forms a chemical bond with oxygen to create oxyhaemoglobin, this carries oxygen to tissue cells and is formed in lung capillaries.
The Respiratory System
Respiration is an internal and external system.
Externally respiration involves breathing, gaseous exchange and blood transportation. Internal respiration is carried out inside the body cells and is also known as tissue respiration.
When we inhale (inspiration) environmental air it enters through our nose or mouth, travels down the pharynx to the trachea and then branches off through the Bronchus, finally entering the lungs.
Within the lungs there are bronchiole and alveoli which are filter systems to separate useful products such as oxygen from harmful substances such as carbon dioxide.
In the alveoli, gaseous exchange occurs; this is where oxygen diffuses across the blood capillaries and into the blood stream and carbon dioxide diffuses into the alveoli to be expelled when we exhale (expiration).
B. Stretch and M. Whitehouse (2007) define diffusion as “The movement of molecules of a gas or a liquid from a region of high concentration to a region of low concentration”. (B. Stretch and M. Whitehouse, 2007, Page: 236)
The lungs are found in the thorax (chest) along with the heart. The lungs and heart are protected by the ribs and a tough membrane, the Pericardium – this protects the lungs and heart from any friction that may occur.
The nose is a moist entrance for air to travel through; it is lined with ciliated mucous membrane which is full of blood capillaries. As the air passes through the nose it is warmed to near body temperature and moistened by the ciliated mucous membrane. Dust, carbon particles, pathogens and other foreign materials have been filtered from the air by the time it reaches the throat by the small hair (cilia) that lines the inside of the nose.
Within the trachea is the larynx which produces sound; this is protected by the epiglottis which is a cartilage flap which prevents solids and liquids from entering the lungs when swallowing.
The trachea and bronchi are lined with rings of cartilage which prevents them from collapsing. The shape of the cartilage in the trachea is C-shaped as this tube presses against the oesophagus (the tube in which solids and liquids enter the digestive system).
When the air enters the lung, the bronchus divides repeatedly giving the lungs a large surface area in order to accommodate for more oxygen.
The inner lining of the trachea and bronchi are lined with columnar epithelium cells which are ciliated and secrete mucus – this is a defence mechanism of the lungs as the mucus collects any particles that may cause harm or infection and expels these by contracting the muscles within the lungs to force the mucus from the lungs to the mouth.
The function of the respiratory system is to replenish the oxygen supply within the body and remove waste products such as water and carbon dioxide.
The Digestive System
The digestive system can be divided into four processes: Ingestion, Digestion, Absorption and Excretion.
These four stages are the main functions of the digestive system.
Ingestion begins in the mouth, food is taken in and formed into a small ball called bolus – this is formed by the food mixing with saliva and the ‘mixing’ action provided by the movement of teeth and the tongue. Saliva is a digestive juice secreted by the salivary glands that contains salivary amylase, which is an enzyme that begins to digest carbohydrates. This first process is mechanical digestion and has the important function of physically breaking down the food or substances.
The bolus is then swallowed and passed from the pharynx to the stomach in the abdomen via the digestive tract (or alimentary canal/ oesophagus). Bolus is able to pass down the oesophagus due to muscular contractions, peristalsis.
The stomach is located behind the rib cage, under the diaphragm, on the left hand side of the body. When the bolus reaches the stomach via the oesophagus then the digestive process begins.
Digestion begins when the bolus enters the stomach – the strong walls of the stomach roll to churn the food, at this time gastric juices are secreted from the gastric glands which break down the bolus further into a paste called chyme.
Gastric juice contains gastric protease and hydrochloric acid which means the contents of the stomach is highly acidic so the epithelial lining of the stomach contains goblet cells which secrete mucus to protect the walls of the stomach from acid erosion.
The duodenum is the first part of the small intestine. The liver and pancreas secrete digestive enzymes into the duodenum; the walls of the duodenum also secrete enzymes juices (succus entericus) that continue the digestion concentrating on the digestion of proteins, carbohydrates and lipids.
Absorption begins in the ileum which is the remaining part of the small intestine. The ileum has a large surface area due to the long length, folded sides and the villi covered epithelial cells that are further coated in microvilli. The increased surface area means that all nutrients from digested food can be absorbed.
Excretion begins in the large intestine which comprises of the colon and the rectum.
The function of the colon is to slow down the passage of food waste. During the stages of ingestion and digestion glands have secreted digestive enzyme juices onto the chyme turning the ingested food into a liquid substance. A lot of water is forced into the chyme and because the body cannot loose too much water the colon allows time for the body to absorb the left over water,
Chyme and waste products are moved from the colon to the rectum by peristalsis.
The function of the liver is to produce bile which travels through the bile duct to the duodenum. Bile is stored in the gall bladder for a short time and although has no enzymes, it contains salts that cause emulsification of lipids in the duodenum.
The liver also removes glucose from the blood when it enters the small intestine. The liver breaks down amino acids to form glycogen and urea which is then transported through the bloodstream to the kidneys.
The function of the pancreas is to secrete pancreatic juice that is rich in enzymes as well as to secrete alkaline salts which neutralise the acidity of the secretions made by the stomach. The pancreatic juice breaks food molecules into amino acids, glucose, fatty acids and glycerol so that the body can absorb the nutrients from the digested food.
From all of the systems I have explained in this report without anyone of them the human body would not be able to function effectively to survive. The following table summarises the functions of each of the major body systems I have spoken of.
References.
Figure 1: Structure of the Renal System
[Accessed 23/11/10]
Figure 2: The Nervous System
[Accessed 23/11/10]
Figure 3: The Structure of the Nervous System
[Accessed 23/11/10]
Figure 4: Endocrine System
[Accessed 23/11/10]
Figure 5: Major Endocrine Glands
[Accessed 23/11/10]
Figure 6: Female Reproductive System
[Accessed 23/11/10]
Figure 7: Male Reproductive System
[Accessed 23/11/10]
Figure 8: Musculo-Skeletal System
[Accessed 23/11/10]
Figure 9: Types of Joints
[Accessed 23/11/10]
Figure 10: Synovial Joint
[Accessed 23/11/10]
Figure 11: The Structure of the Immune System
[Accessed 23/11/10]
Figure 12: Microorganisms that can affect the Immune System
[Accessed 23/11/10]
Figure 13: The lymphatic System
[Accessed 23/11/10]
Figure 14: The heart
[Accessed 23/11/10]
Figure 15: Double Circulation of the heart.
Circulatory System.
[Accessed 23/11/10]
Figure 16: The Structure of the Respiratory System
[Accessed 23/11/10]
Figure 17: The Structure of the Digestive System
[Accessed 23/11/10]
Figure 18: Summary of the functions of the major systems of the body.
(B. Stretch, M. Whitehouse (2007) BTEC National Health and Social Care Book 1. Oxford: Heinemann) Page 221.)
Bibliography.
Website:
( GREENFACTS [2009] Endocrine System [online] Greenfacts UK. Available from: . [Accessed: 27/11/2010]).
Website:
(BBC UK. Science human body and mind: muscles – skeletal, smooth and cardiac [online] BBC UK. Available from: [26/11/10]).
Textbook:
(B. Stretch, M. Whitehouse (2007) BTEC National Health and Social Care Book 1. Oxford: Heinemann) Pages 217 – 241.
Website:
(BUPA UK. (May 2009) Cardiovascular System. [Online] Bupa UK. Available from: [26th November 2010])
All information in this report has been referenced above, any information that has not been referenced was from my own knowledge.
Eleisha Wallace-Barber.
Anatomy and Physiology.
BTEC level 3 diplomas in Health and Social Care.