B11 - Hormonal coordination

Question 1

What is the endocrine system and compare it to the nervous system

Answer 1

A system of glands that secrete hormones (chemicals) into the blood where it is carried around the body. Produces a slower, longer lasting effect than the nervous system.

Question 2

Key glands in the endocrine system and their roles

Answer 2

• Pancreas - blood glucose maintenance
• Testes/Ovaries - control secondary sexual characteristics
• Adrenal glands - produced in times of fear or stress
• Thyroid - basal metabolic rate
• Pituitary

Question 3

Role of the pituitary gland

Answer 3

‘Master gland’ that releases a number of different hormones. They act on other glands and stimulate other hormones to be released

Question 4

What happens if blood glucose level is too high e.g. meal with carbs eaten

Answer 4

• Conc of blood glucose rises
• Detected by receptors in pancreas and releases insulin
• Insulin stimulates cells to take up glucose
• Also tells liver and muscles to store glucose as glycogen

Question 5

What happens if blood glucose level is too low

Answer 5

• Detected by receptors in pancreas
• Release glucagon
• This stimulates the liver cells to convert glycogen back into glucose

Question 6

What happens with Type 1 Diabetes

Answer 6

• The pancreas doesn’t produce enough insulin
• Their blood glucose levels rise higher and stay high

Can be inherited

Question 7

Symptoms of type 1 diabetes

Answer 7

• Glucose in urine
• Patient feels thirsty as lots of urine is produced to get rid of glucose
• Patient feels tired as glucose can’t be used for respiration
• Loss of weight

Question 8

What happens with Type 2 Diabetes

Answer 8

• Body cells have stopped responding to insulin
• Similar symptoms to type 1 diabetes

Linked to obesity, age, lack of exercise

Question 9

How to treat type 1 diabetes

Answer 9

• Insulin injections before meals
• Pancreas transplants
• Stem cells (future)

Question 10

How to treat type 2 diabetes

Answer 10

• Losing weight
• Regular exercise
• Carb controlled diet

Question 11

How does a person’s blood glucose concentration stay level

Answer 11

• If blood glucose rises, insulin released which reduces blood glucose
• When it falls to a certain level, glucagon is released which increases blood glucose
• Each hormone inhibits its own production and have opposite effects
• This is a negative feedback system

Question 12

What does testosterone control and where is it produced

Answer 12

• Stimualtes sperm production
• Produced in the testes

Question 13

Describe the menstrual cycle

Answer 13

• Lining of uterus breaks down
• It then builds in preparation for release of egg
• Egg is released
• If sperm is present, egg impants into lining but if not, cycle repeats

Question 14

Function of hormones in the menstrual cycle

Answer 14

• FSH - Causes an egg to mature
• LH - Stimulates ovulation
• Oestrogen - builds up endometrium
• Progesterone - maintaining endometrium

Question 15

Describe how the hormones in the menstrual cycle interact

Answer 15

• FSH released by pituitary gland
• Travels to ovaries and stimulates egg to be mature. Also stimulates release of oestrogen from ovary
• Oestorgen thickens endometrium and inhibits FSH secretion. Stimulates LH secretion
• LH secreted from the pituitary stimualtes ovulation
• Empty egg follicle secretes progesterone
• This stops the secretion of FSH and LH. Also keeps the lining of the endometrium

Question 16

Hormonal methods of contraception and advantages and disadvantages of them

Answer 16

• Daily pill - prevent release of FSH - stops eggs maturing. Very effective but can have side effects such as breat cancer or blood clots. Also can be easily forgotten
• Patch, injection or implant - more convenient that the pill. Contain progesterone.
• No hormal contraception methods protect against STIs

Question 17

Barrier methods of contraception and advantages and disadvantages of them

Answer 17

• Condom and diaphragm - prevent sperm from reaching egg
• Advantages - don’t need specialist application, prevent against STIs
• Disadvantages - can break

Question 18

What is an IUD and advantages and disadvantages of it

Answer 18

• Coil insterted into uterus by professional
• Advantages - very few side effect
• Disadvantages - dont protect against STIs, can prevent future pregnancies

Question 19

Steps during IVF

Answer 19

• Mother is given FSH and LH to mature lots of eggs
• Eggs collected from mother
• Sperm is collected and fertilises eggs in lab
• Once eggs have grown into embryos, they are inserted into mother

Question 20

Problems with IVF

Answer 20

• Not very high success rates
• Stressfu for both parents
• Physically demanding on mother
• Mutiple births could be dangerous
• Ethical issues surroundings destruction of unused embryos
• Very expensive

Question 21

Role of adrenaline and where is it released from

Answer 21

• Adrenal glands on top of kidneys release adrenaline into blood in times of stress or fear - FIGHT OR FLIGHT
• Increases heart rate - more oxygen and glucose to brain
• Dilate pupils
• Glycogen converted to glucose
• Blood diverted from digestive system to vital organs

Question 22

Role of thyroxine and where is it released from

Answer 22

• Released by thyroid gland in neck
• Stimulates basal metabolic rate
• Growth + development

Question 23

How are thyroxine levels controlled by negative feedback

Answer 23

• Thyroxine levels monitored by brain
• When thyroxine falls, brain detects this and pituitary secretes TSH
• TSH stimulates thyroid to release more thyroxine
• Thyroxine levels increase, detected by brain
• This decreases TSH secretion from the pituitary