W3 - Endocrine System (Lecture)

Question 1

What is the 2016 definition of a HM?

Answer 1

Long distance chemical mediator secreted by an endocrine gland into the blood which transports it to the target cell

Question 2

What can be improved about the HM definition from 2016?

Answer 2

It’s not always blood and it’s not always ovr a ‘long’ distance

Question 3

What are the 2 differences between NTMs and HMs?

Answer 3

NTM - released across synapse and therefore short distances, HM - released by gland and travel in circ system therefore longer distances

Question 4

What are the 6 types of feedback loops?

Answer 4

Direct FL, first order FL, second order FL, third order FL, -ve and +ve FLs

Question 5

What two ways can +ve FLs act?

Answer 5

Exponentially upwards OR downwards

Question 6

The main example of a +ve FL is childbirth, the intial contractions cause stimulus to the stretch sensitive neurons in the cervix, what does this provoke and when does this stop?

Answer 6

Release of oxytocin (HM) from post PG to cause uterine muscles to contract more to help move baby towards cervix, this stops when stretch is lost

Question 7

What is childbirth an example of?

Answer 7

NEuroendocrine reflex

Question 8

What happens when there’s high blood sugar?

Answer 8

High - insulin gets released from islets of Lang + it binds to target cells, kinase cascade is activated, leads to exocytosis of GLUT4 channels for glucose uptake

Question 9

What happens when there’s low blood sugar?

Answer 9

Low - glucagon released from islets of Lang, binds to target cells to promote glycogenolysis

Question 10

What do cells do in response to adrenaline?

Answer 10

Vasoconstriction, insulin suppression, sensitisation of CNS and release of aas/NEFAs (energy source)

Question 11

Why are responses to adrenaline beneficial?

Answer 11

Fight/flight

Question 12

What triggers release of adrenaline?

Answer 12

Neuronal signal triggers adrenaline release from vesicles in medulla of adrenal gland to be released into blood

Question 13

PNMT is produced in the adrenal gland, it converts noradrenaline to adrenaline but PNMT gene is only expressed when theres high levels of ??? present?

Answer 13

Glucocorticoids e.g. cortisol

Question 14

All cells are capable of producing PNMT, what is the reason only cells in the adrenal gland do?

Answer 14

Area of high levels of glucocorticoids present in adrenal gland compared to elsewhere

Question 15

What are neural crest cells?

Answer 15

They can act as neurons but are mobile towards particular signals

Question 16

Some crest cells invade the middle of the adrenal gland during development and are responsible for adrenaline production (NA –> A), what are these cells called?

Answer 16

Chromaffin cells

Question 17

How do neural crest cells form during development?

Answer 17

The neural plate has borders (NPBs), the plate folds in at the NPBs to create the neural tube (eventually SC) and the cells from the borders migrate away as neural crest cells

Question 18

Chromaffin cells have cell bodies but no ??? so they are neurons that go nowhere

Answer 18

Axons

Question 19

How may you test if melatonin/cortisol are affecting sleep if either are?

Answer 19

Inject someone with both and compare effects or remove glands

Question 20

Which glands produce melatonin and cortisol?

Answer 20

Melatonin - pineal glands, cortisol - adrenal

Question 21

Melatonin and serotonin work in diurnal rhythm regulation, and the balance of the two regulates sleep, what may happen to night shift workers?

Answer 21

Insomnia due to severe disruption to diurnal cycles, peaks of melatonin can be decreased

Question 22

When looking at night shift workers diurnal cycles, what should be considered?

Answer 22

What job they do and stress coping mechanisms

Question 23

What does hyper-, hypo- and -mia mean?

Answer 23

Hyper - too much, hypo - too little, -mia - in the blood (hyperglycemia (too much glucose in the blood)

Question 24

Hormone and receptor need to be present to form a ??? and then a ??? elicits a target cell response

Answer 24

H-R complex, and activated H-R complex

Question 25

What happens when there is hormone resistance?

Answer 25

The target cell has a lack of response to the activated H-R complex

Question 26

What does it mean when a receptor is constitutively activated?

Answer 26

The target cell response is caused without the need for the ligand/HM

Question 27

Why must dosages of HM inhibitors be titrated?

Answer 27

Too much can switch from excess dosage to deficiency