B7

Question 1

What is produced in the;
Pituatary gland,
Thyroid,
Pancreas,
Adrenal,
ovaries,
testes.

Answer 1

Pituitary-FSH,LH,TSH.
Thyroid-Thyroxine.
Pancreas-Insulin.
Adrenal-Adrenaline.
Ovaries-Oestrogen,progesterone.
Testes-testosterone.

Question 2

How are hormones transported from endocrine glands to their target organs?

Answer 2

Chemical molecules released directly into blood. Secreted by a gland and released into the blood and carried by it. Slower action, act for a long time, act in a more general way than nerves.

Question 3

Effects of adrenaline from adrenal glands to prepare body for fight or flight

Answer 3

Increased heart rate-binds to specific receptors in the heart. Heart muscles contract more frequently and more forcefully so heart rate and blood pressure increases.
Increased blood pressure-same reason as heart rate.
Increased blood flow to muscles-because of the increased heart rate higher rate of blood movement so cells receive more glucose and oxygen for respiration.
Raised blood sugar levels-adrenaline binds to receptors in lover meaning liver breaks down glycogen stores to release glucose. Increases blood glucose levels so more glucose in blood to be transported to cells.

Question 4

How thyroxine controls metabolic rate as an example of negative feedback

Answer 4

Low levels of thyroxine stimulate hypothalamus to release TRH.
TRH stimulates pituitary gland to release TSH.
TSH stimulates thyroid gland to release thyroxine so blood thyroxine levels rise back to normal.
If thyroxine levels are normal or too high, release of TRH from hypothalamus is inhibited which inhibits/reduces production of TSH meaning levels fall or remain same.

Question 5

Stages of the menstrual cycle as well as in relation to hormones present

Answer 5

Stage 1(day 1-menstruation)-lining of uterus starts to break down and is released.
Stage 2(4-14)-uterus lining is repaired and builds up again until becomes a thick spongy layer full of blood vessels, ready for egg.
Stage 3(14)-Egg develops and is releases from ovary(ovulation) at roughly day 14.
Stage 4(14-28)-Lining is maintained for roughly 14 days. If no egg lands on wall by day 28, lining starts to break down again and cycle is repeated.

Question 6

Roles of hormones in menstrual cycle

Answer 6

FSH-released by pituitary, causes follicle(egg and surrounding cells) to mature in one ovary, stimulates oestrogen production.
Oestrogen-released by ovaries, causes lining of uterus to thicken and grow, high level stimulates an LH surge(rapid increase).
LH-released by pituitary, LH surge stimulates ovulation at day 14-follicle ruptures and egg is released, stimulates remains of the follicle to develop into corpus luteum which secretes progesterone.
Progesterone-released by corpus luteum after ovulation, maintains lining of uterus, when prog falls means low oestrogen level and lining breaks down, low prog level allows FSH to increase and then whole cycle starts again.
Progestorone and oestrogen inhibit the release of FSH and LH.

Question 7

Contraception

Answer 7

Oestrogen and prog inhibit the release of FSH and LH so no egg matured or relased meaning cannot be fertilised as oes and prog levels are always high.
Oes inhibits FSH.
Prog produces thick cervical mucus which prevents sperm entering cervix and reaching egg.
Mini-pill and injection only contain prog.
Physical barrier to stop sperm meeting eggs.
No hormonal side effects like headaches, acne and mood change and do protect against STIs.

Question 8

Clomifene therapy

Answer 8

Some women infertile because dont ovulate regularly.
Take clomifene and cause body to release more FSH and LH which stimulates egg maturation and ovulation.
Knowing when woman is ovulating can increase chances of pregnancy.

Question 9

IVF

Answer 9

Collecting eggs from woman’s ovaries and fertilising them in a lab with the man’s sperm.
Grown into embryos.
Once tiny balls of cells few transferred to woman’s uterus to improve chance of pregnancy.
FSH and LH are given before egg collection to stimulate egg production(so multiple can be collected).
Example of ART(assisted reproductive tech).
Involves eggs being handles outside the body and usually fertilised.

Question 10

Importance of maintaining constant internal environment

Answer 10

Body needs right conditions to function properly(enzyme action).
Dangerous for health if conditions vary too much from normal levels.
Body has to respond to internal and external changes whilst balancing inputs and outputs.

Question 11

Negative feedback

Answer 11

Helps keep conditions in body steady.
If condition changes away from normal, response triggered that counteracts change. E.G. rise in blood glucose cause a response that lowers blood glucose levels and vice versa.

Question 12

Importance of thermoregulation on enzyme activity

Answer 12

Allows normal metabolic processes to occur without the risk of loss of function from enzymes due to denaturing (too hot) or not working fast enough/don’t have enough energy to work because too cold.

Question 13

Importance of osmoregulation on animal cells

Answer 13

Can avoid too much water loss(not enough to carry out cells processes and could disrupt metabolism) and avoid too much water(cells could burst).

Question 14

How thermoregulation takes place as well as the role of the dermis, epidermis and hypothalamus

Answer 14

Role of hypothalamus- thermoregulatory centre in it acts as a personal thermostat. contains receptors that are sensitive to blood temp in the brain .
Receives impulses from receptors in the skin that provide info about external temp. Receptors located in epidermis(outer skin layer) and in the dermis(deeper skin layer).

Question 15

How thermoregulation takes place with reference to shivering, vasoconstriction, vasodilation.

Answer 15

When too hot;
Erector muscles relax, so hair lies flat.
Lots of sweat produced(water and salts) in sweat glands in dermis. Released on skin’s surface through pores in epidermis. When sweat evaporates, transfers energy from skin to environment cooling you down.
Vasodilation-blood vessels close to surface widen(dilate). Allows more blood to flow near surface, so transfers more energy into surroundings, cooling you down.
When too cold:
Erector muscles contract. Hairs stand on end to trap an insulating layer of air near surface so less energy transferred to surroundings.
Very little sweat.
Vasoconstriction-blood vessels contrist means less blood flow near surface so less energy transferred to surroundingd.
Shivering- muscles contract automatically increasing rate of respiration which transfers more energy to warm the body.

Question 16

how does insulin control blood glucose concentration

Answer 16

When glucose conc too high insulin is added.
insulin secreted from pancreas to high glucose blood. Then has too much glucose but insulin too.
Glucose and insulin move into the liver and muscle cells. Insulin makes liver turn glucose into glycogen. Blood glucose then reduced.

Question 17

How does glucagon regulate blood glucose conc

Answer 17

When glucose conc too low, glucagon is added. Blood with too little glucose has glucagon added secreted from the pancreas. Blood has too little glucose and glucagon as well. Glucagon moves into liver and makes liver turn glycogen into glucose. Glucose released into blood by liver. Blood glucose increased.

Question 18

Info about blood glucose

Answer 18

-Eating foods with carbs puts glucose into blood from small intestine. Normal metabolism of cells removes glucose from blood. Vigorous exercise removes much more glucose from blood. Excess glucose stored as glycogen in liver and muscles. When stores are full, excess glucose stored as lipid(fat) in the tissues. Changes in blood glucose monitored and controlled by pancreas using insulin and glucagon.

Question 19

Cause of type 1 diabetes and how controlled

Answer 19

Caused by lack of insulin where pancreas produces little or no insulin. Means persons glucose can rise to a level which can kill them.
Treated with insulin therapy(injecting insulin into subcutaneous tissue(fatty tissue under the skin). Usually at mealtimes to ensure glucose removed from blood quickly after food digested. Stops glucose level from being too high and very effective. Limit intake of simple carbs. Take regular exercise to remove excess glucose from blood.

Question 20

Cause of type 2 diabetes and how controlled

Answer 20

Where pancreas does not produce enough insulin or when they become resistant to insulin(cells dont respond properly to hormone). Blood glucose levels rise therefore. correlation between obesity and type 2 diabetes meaning obese people increased risk of developing it.
Carb controlled diet and exercise regime as carbs are controlled into glucose so raise glucose conc in blood.
Medication and insulin injections.

Question 21

BMI equation

Answer 21

mass/height(m)^2
Obese=over 30

Question 22

Waist to hip ratio calculation

Answer 22

Waist circumfrence/hip circumfrence(in same measurement)
above 1 for men and 0.85 for women associated with increased risk of type 2 diabetes.

Question 23

Structure of the urinary system

Answer 23

Kidneys
Renal artery
Renal vein
Ureter
bladder
urethra

Question 24

Main roles of kidneys

Answer 24

Removal of urea from blood.
Urea produced in the liver from the breakdown of excess amino acids.
Adjustment of ion levels in the blood.
Adjustment of water content of blood.

Question 25

How structure of nephron related to it’s function in filtering blood and forming urine

Answer 25

1)liquid parts of the blood(water, urea, ions, glucose) is forced out the glomerulus into bowmans capsule at high pressure(ultrafiltration). Bigger molecules(e.g. proteins) and blood cells can’t pass through membranes and are not forced out.
2)As liquid flows along nephron, useful substances reabsored. All glucose is selectively reabsorbed(moved back into blood against conc grad)(in porximal conculated tubule). Sufficient ions are reabsorbed. Sufficient water is reabsorbed.
3) Whatever is not reabsorbed, continues out of nephron via collecting duct. Passes into ureter and down to bladder as urine. Urine released through urethra.
Bowmans capsule, glomerulus, proximal convoluted tubule, loop of henle(recovery of water and sodium chloride from urine), distal convoluted tubule, collecting duct.

Question 26

Effect of ADH on permeability of collecting duct in regulating water content of the blood

Answer 26

Anti-diuretic hormone controls amount of water reabsorbed in kidney nephrons. (water gain=)Brain monitors water content of blood and instructs pituitary gland to release ADH into blood according to how much needed. ADH makes collecting ducts of nephron more permeable if more water needs to be reabsorbed into blood preventing dehydration and vice versa. Negative feedback controlled.
More ADH=less urine produced.

Question 27

Kidney dialysis

Answer 27

1)Kidney failure=can’t filter blood properly.
2)Has to be done regularly to keep dissolved substances at right conc to remove waste.
3)Dialysis fluid has same conc of slats and glucose blood plasma(means aren’t removed from blood).
4)Barrier permeable to things like ions and waste substances but not big molecules. Means waste substances(urea) plus excess ions and water from blood move across membrane into dialysis fluid. Cells and proteins stay in blood. Constant supply of fresh dialysis fluid.

Question 28

Organ(kidney)donation

Answer 28

Only cure for kidney disease is transplant.
Healthy ones usually transplanted from recently deceased people on organ donor register or carry donor card(relatives agree provided).
Can be rejected by patient’s immune system(treated foreignly and attacked by antibodies).To prevent;
-Donor with closely matching tissue type chosen.
-Patient treated with drugs to suppress immune system so won’t attack transplanted kidney.

Question 29

What is urea produced from?

Answer 29

The breakdown of excess of amino acids in the liver.(low protein diet could help).