endocrine system

Question 1

what are hormones

Answer 1

chemical messengers that travel in the bloodstream and trigger effects in cells/tissues by binding onto protein receptors on the cell membrane

Question 2

what is method 1 of hormone action

Answer 2

bigger hormones that don’t cross the cell membrane easily bind to receptors on the surface and a second messenger sends the signal into the cell

Question 3

what is the most common second messenger

Answer 3

cyclic AMP which activates enzyme systems involved in synthesis and secretion making the cell respond

Question 4

what is method 2 of hormone action

Answer 4

no second messenger, hormones alter the target cells by activating DNA

Question 5

what is the function of the hypothalamus (2)

Answer 5

possess nerve receptors
produce releasing hormones

Question 6

what is the function of the pituitary gland (3)

Answer 6

produce stimulating hormones

anterior receives hormones via blood supply from the hypothalamus.

posterior receives nerve supply from the hypothalamus triggering hormone production.

Question 7

what hormones does the posterior pituitary produce? (2)

Answer 7

Anti-diuretic hormone (water balance with osmoreceptors in the hypothalamus)

oxytocin (stimulates labour contractions, sense of well-being, maternal bonding and behaviour)

Question 8

what hormones does the thyroid produce (3)

Answer 8

Thyroxine (T4)
Triiodothyronine (T3)
Calcitonin (produced by the parathyroid, removes excess calcium from blood into bone)

T3 and T4 regulate basal metabolic rate (BMR) - the basic level of energy needed to maintain resting metabolism via negative feedback

Question 9

how is the metabolic rate regulated (6 steps)

Answer 9

low thyroxine levels are detected.
the hypothalamus stimulates the pituitary.
pituitary secretes thyroid stimulating hormone.
thyroid responds and secretes thyroxine.
thyroxine enters the blood and affects the metabolic rate of all cells.
the brain stops stimulating the pituitary to produce TSH.

Question 10

what should the blood glucose concentration be before a meal and 90 mins after

Answer 10

before 4.0-5.9 mmol/L
after 90mins under 7.8 mmol/L

Question 11

what cells produce glucagon and insulin

Answer 11

glucagon - alpha cells in pancreatic islets
insulin - beta cells in pancreatic islets

Question 12

how does insulin and glucagon work

Answer 12

insulin - binds to cell surface receptors and triggers reactions in the cell to increase glucose uptake via glucose transport proteins

glucagon - converts glycogen to glucose to be released into the bloodstream. switched on during exercise and when hungry. stimulated by the SNS

Question 13

what happens when there is a fall in glucose (4 steps)

Answer 13

insulin secretion decreases and glucagon is produced from alpha cells in the pancreatic islets.

less glucose is taken up by cells and respired.

stored glycogen in the liver and muscle is converted into glucose by glucagon.

fatty acids are converted into glucose.

Question 14

what happens to insulin production as we age

Answer 14

pancreatic islets produce less insulin so eating excess sugar and fat reduces the number of insulin receptors available on the surface of the cell.

as a result, the cell doesn’t let much glucose in.

Question 15

what kind of conditions are hyperthyroidism and type 1 diabetes

Answer 15

hyperthyroidism = metabolic disorder
type 1 diabetes = auto-immune disease

Question 16

what percent of people who have hyperthyroidism have graves disease and what percentage suffer from symptoms

Answer 16

70% of people with hyperthyroidism have Graves disease.
30% may experience symptoms such as bulging eyes.

Question 17

what happens when there is a rise in glucose levels (4 steps )

Question 18

what is the connection between being overweight and type 2 diabetes?

Answer 18

being overweight means there is excess stored glucose, this makes the glucose receptors resistant to insulin

Question 19

what is the significance of eating pasta in glucose regulation

Answer 19

pasta is a carbohydrate which then breaks down into glucose. The glucose can be stored for later use and is slowly released.

Question 20

what hormone is switched on after running for a long period of time

Answer 20

glucagon. stored glycogen is converted into glucose for more energy by glucagon produced in the islets alpha cells

Question 21

what is the significance of insulin receptors on the surface of liver and muscle cells

Answer 21

glucose is stored in liver and muscle cells so receptors are on the surface of these cells.

Question 22

name 4 functions of the hormone insulin

Answer 22

increase glucose uptake into a cell, activating glucose transporter proteins.

convert glucose to glycogen.

convert glucose into fatty acids.

speed up respiration, to break down more glucose.