Endocrine system

Question 1

how it works

Answer 1

the excretion of hormones (chemical messages) from glands into BS for transportation to targeted tissues (effectors) which have complementary receptors to form a binding complex

Question 2

what cells are exposed to hormones?

Answer 2

ALL cells are exposed to hormones as they are transported in the BS

but only complementry cells have the necessary receptors to react

Question 3

in comparison the the nervous system, endocrine messages are….

Answer 3

slower + longer in duration

Question 4

function (1) + how (5)

Answer 4

MAINTAIN HOMEOSTATSIS via:

1. Regulate metabolic processes
2. regulate water + electrolyte balances
3. aid in transportation of substances across cell membranes
4. control rate of chemical reactions
5. role in reproduction, growth + dev.

Question 5

what does the endocrine system control-> but not key functions (10)

Answer 5

1. Metabolism
2. Food digestion + intake
3. tissue development
4. ion levels
5. water balance
6. heart rate + BP
7. glucose + nurient levels in blood
8. reproductive functions + milk production
9. urine production
10. immune response

Question 6

structure of hormones

Answer 6

an aqueous substance- must be water soubable to be transported around the blood: some are naturally water soulable some are lipid soluable therefore they require chaparone proteins

Question 7

characteristics of water-soluable hormones (5)

Answer 7

1. dissolve in plasma
2. ‘free’ hormones as do not require protein to bind to for transportation
3. relatively large in size
4. do not easily diffuse through cell-membranes therefore require receptor to diffuse into cells (receptors external)
5. short life-span: are rapidly broken down by hydrolytic enzymes

Question 8

characteristics of lipid-soluable hormones (5)

Answer 8

1. low-soluablity in aqueous fluids
2. require chaperone proteins to allow transport through BS
3. longer-lifespan (due to presentence of chaparone proteins)
4. relatively small in size
5. pass through lipid-cell-membranes and find receprtors internally

Question 9

hormone life-span

Answer 9

variable as it depends on enzymes present in blood. measured via half-life

Question 10

half-life of hormones

Answer 10

the time taken for 50% of the circulating hormone to be removed from the blood