SB7 Flashcards
Hormonal system
Uses chemical messengers called hormones to cause responses in the body
What is a hormone?
Chemical messenger
What are the endocrine glands?
Pituitary
Thyroid
Adrenals
Ovaries
Testes
Pancreas
What hormones does the pituitary gland produce?
ACTH
FSH
LH
Growth hormones
What hormone does the thyroid gland produce?
Thyroxine
What hormones do the pancreas produce?
Insulin and glucagon
What hormones do the ovaries produce?
Oestrogen and progesterone
What hormone does the adrenal gland produce?
Adrenalin
What hormone does the testes produce?
Testosterone
What is the organ that is affected by the hormone?
Target organ
How does the hormone affect the organ?
It changes what the organ is doing
Metabolic rate
The rate at which the energy stored in your food is transferred by all the reactions that take place in your body
Resting metabolic rate
Measured with the body at rest, in a warm room, and a long time after the person last ate
What hormone affects metabolic rate?
Thyroxine
Where is thyroxine excreted from
Thyroid gland
What are the effects of thyroxine?
Causes heart cells to contract more rapidly
Increases the rate that proteins and carbohydrates are broken down in the cells
What is the control of thyroxine concentration an example of?
Negative feedback
What 2 hormones control the amount of thyroxine produced?
TRH
TSH
Where is TRH secreted from?
Hypothalamus
Where is TSH secreted from ?
Pituitary
Explain negative feedback in terms of thyroxine concentration
An increase in thyroxine concentration inhibits the release of the hormones that control the release of thyroxine, therefore creating less thyroxine produced in the blood, and vice versa
Where is adrenalin secreted from
Adrenal glands
How much Adrenalin is secreted in normal conditions?
Very little
What happens to the amount of Adrenalin released when a situation is frightening?
An increase of impulses reaches the adrenal glands and triggers a lot of adrenaline to be released into the blood
What are the target organs affected by Adrenalin
Heart
Liver
What happens when Adrenalin affects the liver
It causes the breakdown of glycogen which promotes glucose molecules being released into the blood which means more respiration can take place.
What happens when adrenaline affect the heart
Heart muscle cells contract quicker which means the heart rate is higher and they contract stronger which means there’s more blood pressure
What happens to the blood vessels when adrenaline affects them
The diameter of blood vessels widens which means there is more blood flow to the muscles and the diameter of blood vessels that lead to different organs narrows which means there is less blood flow to those organs which also increases blood pressure
Describe the different stages of the menstrual cycle
The first stage of the menstrual cycle is menstruation when you have your period and the lining breaks down
The second stage is after the period the uterus lining starts to thicken again
The third stage happens around day 14 which is ovulation which is when the egg is released
Stage four is when the uterus lining thickens and the last stage is when the egg cell travels along the oviduct to the uterus, where it can be fertilised and grow into an embryo
What hormones control the menstrual cycle
FSH, LH, oestrogen and progesterone
When is oestrogen at its peak
During ovulation
What hormones are released by the ovaries
Oestrogen and progesterone
When is progesterone at its peak?
From day 18 to day 24- this is when uterus lining is at its thickest
Where are FSH and LH secreted from
The pituitary gland
What controls the release of FSH and LH
The concentration of oestrogen and progesterone
What happens to the follicle after ovulation
It becomes the corpus luteum
What releases more LH
High levels of oestrogen
What releases more FSH
Lower levels of progesterone
What happens when there’s high levels of progesterone
FSH and LH are inhibited
What does FSH do
It stimulates growth and maturation of the egg follicle
What does LH do
It triggers ovulation
What happens when oestrogen is increased
The uterine wall is thickened
What releases progesterone
The corpus luteum
What happens when both oestrogen and progesterone fall
It triggers menstruation
How does hormonal contraception work
It uses a progesterone like hormone with or without oestrogen which raises the concentrations of these hormones which means there is no natural fall of concentrations at the end of the menstrual cycle
What does ART stand for
Assistive reproductive technology
What does assisted reproductive technology do
Uses hormones and other techniques to increase the chance of pregnancy
What is clomiphene therapy
It uses the drug clomiphene to increase the concentration of FSH and LH in the blood. This increases the chance of an egg being released
What does IVF do
The woman is given hormones to stimulate the egg follicle maturing
Lots of egg cells are released as a result and taken from the ovary
Sperm is taken from the man and the eggs and sperm are combined in a glass dish
The healthy embryos that result are placed back into the uterus
What problems does IVF overcome
Blocked oviducts or if the man doesn’t produce healthy sperm cells
What happens in glucose levels rise in the blood
Certain cells in the pancreas are stimulated to release insulin which causes cells in the liver and other organs to take in glucose which causes a decrease in blood glucose concentration
What is glucose converted to in the liver and other organs
Glycogen
 What happens when your blood glucose concentration is too low
A hormone called glucagon causes liver cells to convert the glycogen back into glucose which is released into the blood which means that your glucose concentration levels return to their normal state
What is it called when you maintain a constant conditions inside the body
Homeostasis
What happens when you have type one diabetes
The pancreatic cells that produce insulin don’t produce it. This is because the cells have been destroyed by the immune system. This means they can’t control if their blood glucose concentration gets high.
What is the treatment for type one diabetes
They have to you inject insulin into the fat layer of the skin where can enter the blood and control the blood glucose concentration
Explain type two diabetes
Type two diabetes is caused by insulin releasing cells that might not produce enough insulin or their organs just don’t recognise the insulin that’s produced
What is the treatment for type two diabetes
Generally they are kept on a strict diet that is low in sugar and by being physically active. Sometimes people who have severe type two diabetes might be given medicines to reduce the amount of glucose that is released.
What two factors are correlated in terms of type 2 diabetes numbers
The increase number of type two diabetes is correlated to the increase in average body mass. The more fat you have in your body the more likely you are to develop type two diabetes
What is the BMI calculation
Mass divided by height squared
What are the measurement can you use to calculate someone’s mass
Waist to hip ratio
How do you calculate waist to hip ratio
Waist measurement divided by hip measurement
What is Thermo regulation
The control of body temperature to keep the temperature of major organs close to 37°C
What part of the brain monitors temperature
Hypothalamus
Where are the receptors that held the hypothalamus about the temperature of the body
the dermis of the skin
What happens when the hypothalamus detect temperature is falling below 37°C
You can start to shiver which makes your muscles contract and relax rapidly. This energy released from respiration warms you up
Your arrector muscles in the dermis of the skin contract which causes body has to stand up. This doesn’t have much effect of humans but in mammals it helps to warm them.
Reduction of blood flow near the skin keeps warm blood deeper inside the body
What happens when the hypothalamus detects temperatures above 37°
It causes sweating which spreads out over the skin and evaporates. It transfers energy from the skin to the surroundings so the skin cools down.
Also increases blood flow near to the skin which makes it easier for the blood to transfer energy to the air so we cool down.
What happens in the blood when it’s cold
The hypothalamus sends nerve impulses to the arteries in the skin which causes them to narrow. This is called vasoconstriction. This reduces the blood flow in capillaries near the surface of the skin and reduces the energy that is transferred to the surroundings.
What happens in the blood when it’s hot
The hypothalamus causes small arteries to widen which is called vasodilation. This increases blood flow through skin capillaries which brings the warm blood near to the surface of the skin and therefore more energy is transferred to the surroundings
What is body temperature control an example of
Negative feedback
What is Osmo regulation
Osmo regulation is the control of the balance of water and mineral salt in the body
Why is Osmo regulation important
Because if the balance of water and mineral salts is off then the cells may take in or lose too much water by osmosis which can damage cells and get rid of the shape of the cell
What is the function of the urinary system
To remove excess amounts of some substances from the blood including water mineral salts and waste products such as Urea
What happens if you suffer from kidney failure
The waste substances increase in concentration in the blood because that person can’t get rid of it. They will need dialysis to remove these wasting products
How does dialysis work
During dialysis substances are exchanged between the blood and the dialysis fluid by diffusion across the dialysis membrane which is partially permeable to very small molecules like water glucose and you really this is done using a dialysis machine which means that you have to stay at the hospital for a long time
Explain organ donation for kidney failure
They find a match from someone else and put the transplant kidney into the patient’s body. They have to make sure that it is matched well otherwise the body can reject the kidney. Even if they find a match they need to take immuno suppressant drugs for the rest of their life to stop the kidney being rejected
How is urine made in the nephrons in the kidneys
Blood flows through capillaries called the glomerulus which is inside the Bowmans capsule of each nephron
These two structures are adapted to let small molecule of water Yuria and glucose into the nephron. Larger molecules like protein and blood stay in the blood this process is called filtration
The filtration flows along the nephron. Selective reabsorption of the substances or body needs occurs in the nephron. The substances that they need like glucose and minerals are pumped by active transport through the first convoluted tubule.
Water is reabsorbed by osmosis depending on the concentration already in the body. This happens in the loop of Henley and in the collecting duct.
At the end of the nephron the remaining fluid like excess water and urea flows into the ureter which becomes urine
How is the nephron adapted for reabsorption
It has a large surface area
It has micro villi
It has more mitochondria
What happens when the pituitary gland detects that there is too little water in the blood
It releases the hormone ADH which changes the permeability of the collecting duct and means that more water is absorbed by osmosis from the collecting duct back into the blood. This means the concentration of urine is higher.
