The endocrine system

Question 1

What is the difference between exocrine and endocrine glands?

Answer 1

Exocrine:
Duct secretion, non-hormone products to a target organ, body cavity or tissue surface

Endocrine:
Ductless, hormones secretes into interstitial fluid and diffuse into surrounding capillaries, hormones are transported via blood to target

Question 2

What causes hormones to be released?

Answer 2

Nervous system e.g. stress causing epinephrine to be released

Chemical changes in blood e.g. parathyroid glands secrete parathyroid in response to decreased calcium concentration

Hormones e.g.from the pituitary gland stimulates the release of cortisol

Question 3

Give an example of a negative and positive feedback loop?

Answer 3

Negative:
1.blood glucose increases
2.pancreas releases insulin
3.blood glucose decreases

Positive:
1.stretch receptors in uterus activate
2.brain signals for release of oxytocin
3.muscle contracts, restimulating stretch receptors, so more oxytocin is released

Question 4

What is the role of the hypothalamus?

Answer 4

Major integrating link between nervous and endocrine systems

Important regulatory system of the nervous system

Cells synthesise at least 9 different hormones

Question 5

What is the structure of the adrenal glands and what do they produce?

Answer 5

Comprised of inner medulla and outer cortical layer

Produce
glucocortisoids:
cortisol (fat,protein and carbs —> energy, regulates BP)
Corticosterone (regulates immune response, suppressed inflammatory reactions)

Mineralcorticoid (maintains BP by reabsorbing water and NA+ into blood stream

Question 6

What is the role of adrenaline and noroadrenaline?

Answer 6

Adrenaline:
Increases heart rate, blood rushed to muscle and brain for maximum efficiency, spikes blood glucose levels releasing energy

Noradrenaline:
Works with adrenaline, can cause vasoconstriction, inhibits voiding of the bladder

Question 7

What is the role of the pancreas and what are its exocrine secretions?

Answer 7

Functions as an endocrine and exocrine gland

99% of activity is secretion of digestive enzymes and sodium bicarbonate
1% is Islets of Langerhans, secreting insulin and glucagon

Sits on curve of duodenom

Question 8

What are the roles of insulin and glucagon?

Answer 8

Glucagon responds to low blood sugar by accelerating the conversion of glycogen to glucose

Insulin does the opposite