Insulin
Insulin is produced in the beta cells within the pancreas to help to lower the blood glucose levels in the body. The body produces insulin to carry sugar from the blood into the cells in order for it to be burned off as fuel (Vitality. 2010). Diabetes is caused in people whose pancreas is unable to produce enough or any insulin. This affects the body in the following ways the sufferer will feel thirsty, need to urinate more often, feeling tired and can cause muscle to waste away as well as blurring vision.
Human Growth Hormone (HGH)
HGH is a hormone that is secreted from the pituitary gland and is responsible for youth, vitality, energy and all of the health benefits of youth (HGH. 2010). When people have a growth hormone deficiency they can be given a replacement hormone, which helps to stimulate growth. When adults are given growth hormones it can lower the risk of cardiovascular disease and also increase bone density.
Thyroxin
The function of the thyroid gland is to produce thyroxin, which is then responsible for regulating the metabolic speed within the body as well as growth. When there are insufficient amounts of thyroxin being produced in the body it causes the metabolism to slow down and can cause weight gain along with other symptoms such as fatigue, constipation and confusion. It is also possible for the body to produce too much thyroxin; this then results in the metabolism being increased. If this occurs it can cause weight loss/gain, hyperactivity, fatigue and many other symptoms.
Task 2
It is the kidneys task to excrete waste products, maintain homeostasis and release hormones. The kidneys are surrounded by adipose and fibrous connective tissue to help keep them in place and also to protect them. Within the kidneys are three main areas, which are the cortex, which is the outer layer, the medulla is situated in the inner region of the kidney and then there are the renal pyramids.
There are three tasks, which the kidneys perform in order to separate different components within the blood. These are; filtration, reabsorption and secretion. All of these processes occur within the nephrons. The kidneys contain a million nephrons and are functional units within the kidney (Williams, 2000). Small molecules are filtered from the blood, such as salt; these small molecules then get recycled so that any molecules needed in the blood can be reabsorbed before the remainder of the molecules are passed from the tubules/ureter as urine, which is stored in the bladder.
The structure of a nephron is complex and contains many different sections each having it’s own function. Below is a diagram of nephrons with explanations of the function of each section.
Glomerulus are made up of a mass of capillaries, blood enters into the glomerulus, which is attached to a tubule. This is where substances are filtered out such as; glucose, amino acids and vitamins to name a few. These substances are forced out into the Bowman’s capsule. This is known as ultrafiltration. The remainder of the fluid then passes through tubule.
Most of the filtrate from the glomerulus is reabsorbed through the proximal convoluted tubule for example food substances and water. It is dependant on the body’s needs as to how much of this fluid and substances are reabsorbed. This is known as selective reabsorption. Active transport allows substances such as glucose, amino acids, vitamins and sodium and chloride ions to be passed from the proximal convoluted tubule and into the blood. Whilst water passes out of the filtrate and back into the blood by osmosis (Williams, 2000).
The loop of henle has two parts the first being the descending limb and the second the ascending limb. It runs deep in the medulla before turning and joining back up to the cortex. It is here where osmosis allows water to be reabsorbed from the collecting ducts, which means that urine is produced.
Sodium ions are actively pumped out of the distal convoluted tubule from the nephron and into the blood. The walls are affected by hormones regulating the amount of water that passes through the medulla, which affects the concentration of urine. Hormones also control the collecting duct.
It is antidiuretic hormone that affects the permeability of the distal convoluted tubule and collecting duct. It depends on the amount of water that is ingested. Other factors affecting this are salt intake and how much sweat is being produced.
Task 3
By drinking distilled water the participants are increasing the pressure within their bladder therefore forcing urine into the urethra, which then causes urination. This is due to the sensory neurone creating action potential and stimulating stretch receptors as the urine enters into the bladder. This action potential is carried through parasympathetic fibres causing the bladder to contract and skeletal muscle to relax. This process is known as micturition.
The volume of urine decreases after three hours due to urine being released from the bladder that then releases pressure and causes lower action potential.
A lack of antidiuretic hormone (ADH) causes diabetes inspidius. Large amounts of dilute urine and the increase of osmolality of body fluids is caused. Due to small amounts of ADH most of the filtrate is reabsorbed into the distal tubules and so it becomes part of the urine. The kidneys are stimulated by ADH to retain water and reducing blood. The frequency and volume produced are therefore reduced.
