Endocrine Communication

Question 1

What is the endocrine system

Answer 1

Used for communication around the body

Question 2

How does the endocrine system transport its signals

Answer 2

Uses blood circulatory system

Question 3

What are signals released by the endocrine system called

Answer 3

Hormones

Question 4

How many types of hormones are there in

Answer 4

2

Question 5

What are the two types of hormones

Answer 5

1) Protein and pepetide hormones
2) Steroid hormones

Question 6

What are examples of protein and peptide hormones

Answer 6

Adrenaline
Insulin
Glucagon

Question 7

What are examples of steroid hormones

Answer 7

Oestrogen
Testosterone

Question 8

Describe the characteristics of protein hormones

Answer 8

-not soluble in the phospholipid membrane
-do not enter the cell
-need to bind to the cell surface membrane and release a second messenger inside the cell

Question 9

Describe the characteristics of steroid hormones

Answer 9

-can pass through the membrane
-enter the cell and the nucleus
-have a direct effect on the DNA in the nucleus

Question 10

What are hormones released by

Answer 10

Endocrine glands

Question 11

Describe endocrine glands

Answer 11

-ductless-> consist of groups of cells that release the hormone directly into the blood

Question 12

Name the 7 main endocrine glands in the body

Answer 12

1) pituitary gland
2) thyroid gland
3) thymus
4) adrenal glands
5) pancreas
6) ovaries (females)
7) testes (males)

Question 13

What are hormones

Answer 13

chemical messengers that travel through the blood to target organs or tissues, where they trigger specific responses.

Question 14

Why can steroid hormones enter cells directly but peptide hormones can’t?

Answer 14

-Steroid hormones are lipid-soluble so they can dissolve in the fatty cell membrane and pass through it.
-Peptide hormones are water-soluble and can’t pass through the fatty cell membrane so they bind to receptors on the cell surface instead.

Question 15

What does the target cell have to have for non-steroid hormones

Answer 15

-must possess a specific receptor on their plasma membrane that is complementary to the shape of the hormone

Question 16

Why can hormones be carried in the blood without affecting every cell

Answer 16

Because the hormone will only bind to the cells with the correct specific receptor which will initiate a change in the cell

Question 17

What are non-steroid hormones known as

Answer 17

First messengers

Question 18

What are first messengers

Answer 18

Signalling molecules outside the cell that bind to the cell surface membrane and intimate an effect inside the cell

Question 19

What do first messengers usually cause

Answer 19

The release of another signalling molecule in the cell (second messenger)

Question 20

What does the second messenger do

Answer 20

Stimulate a change in the activity of the cell

Question 21

Describe the first and second messenger mechanism

Answer 21

1) the hormone (first messenger) binds to a complementary receptor on the cell surface membrane of the target cell
2) this causes the G protein to be activated
3) the G protein then activates adenyl cyclase
4) the activated adenyl cyclase then converts ATP to cAMP (cyclic AMP) which is the second messenger
5) this second messenger may act directly on another protein or initiate a cascade of enzyme-controlled reactions

Question 22

Where are the adrenal glands found

Answer 22

Just above the kidneys, one on each side of the body

Question 23

How is each gland divided

Answer 23

-the adrenal coretx (the outer)
-the adrenal medulla (the inner)

Question 24

Describe the regions of the adrenal cortex

Answer 24

1) zona glomerulosa= outermost later, secretes aldosterone
2) zone fasciculata= middle layer, secretes cortisol
3) zona reticularis= innermost layer, secretes precursors molecules that are uses to make sex hormones

Question 25

Where is the adrenal medulla found

Answer 25

In the centre of the adrenal gland

Question 26

What does the adrenal gland secrete

Answer 26

Adrenaline
Noradrenaline