Module 5 - Endocrinology Flashcards Preview

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Flashcards in Module 5 - Endocrinology Deck (39):
1

Local vs Long-distance signalling

Local
- paracrine
- synaptic

Long-distance
- endocrine (hormonal)

2

5 types of signalling, signalling molecule and communication type

Endocrine
- signalling molecule: hormones
- long distance

Synaptic
- signalling molecule: neurotransmitters
- short distance

Neuroendocrine
- signalling molecule: neurohormone
- long distance

Paracrine
- signalling molecule: local regulators
- short distance

Autocrine
- signalling molecule: local regulators
- very short distance

3

Define endocrine signalling

secreted molecules diffuse into the blood stream, circulate, and trigger responses in target cells anywhere in the body

4

Define synaptic signalling

secreted molecules diffuse across a synapse, triggering a response in cells of the targeted tissue

5

Define neuroendocrine signalling

secreted molecules are released from a neurosecretory cell, diffuse into the blood stream, circulate, and trigger responses in target cells anywhere in the body

6

Define paracrine signalling

secreted molecules diffuse locally through the ECF, triggering a response in neighbouring cells

7

Define autocrine signalling

secreted molecules diffuse locally, triggering a response in the cell which secreted them

8

Type I vs type II diabetes mellitus

Type I
- insulin dependent
- an autoimmune disorder in which the immune system destroys pancreatic beta cells

Type II
- non-insulin dependent
- involves insulin deficiency or reduced response of target cells dues to change in insulin receptors

9

Posterior vs Anterior pituitary

Posterior
- houses ends of hypothalamic neurons which store hormones
- place of neurosecretion
- no cells
- 'dry' side

Anterior
- houses true endocrine cells which synthesise and release hormones
- portal circulation
- regulated by hormones released into portal blood vessels
- rich in blood supply, gives pink colour
- 'wet' side

10

What is portal circulation?

Capillaries to portal vessels to capillaries

11

What hormones does the posterior pituitary release and what are their target?

Antidiuretic hormone (ADH, Vasopressin) - kidney tubules
Oxytocin - mammary glands and uterine muscles

12

What hormones does the anterior pituitary release?

Gonadotropins (FSH and lutropin)
TSH
ACTH
Prolactin
MSH
GH

13

Tropic vs non-tropic hormones

Tropic - stimulate another endocrine gland to release a subsequent hormone that will act on its target cells

Non-tropic - act directly on target cell

14

Components of Adrenal gland

Adrenal medulla
- inside
- neural tissue
- releases amine hormones (catecholamines) including epinephrine (adrenline) and norephinephrine (noradrenaline)
- triggers fight or flight response

Adrenal cortex
- outside
- true endocrine cells
- releases steroid hormones (corticosteroids) such as mineralocorticoids (aldosterone) and glucocorticoids (cortisol)

15

What is the distinctive feature of steroids?

4 ring structure like cholesterol

16

Steroid hormones plus examples

Corticosteroids
- mineralocorticoids e.g. Aldosterone
- glucocorticoids e.g. cortisol

17

Amine hormones plus examples

Catecholamines
- epinephrine e.g. adrenaline
- norephinephrine e.g. noradrenaline

18

Short term responses to stress

Caused by epinephrine and norepinephrine
- glycogen broken down to glucose to increase blood glucose
- increased blood pressure
- increased breathing rate
- increased metabolic rate
- change in blood flow patterns leading to increased alterness and decreased digestive, excretory and reproductive system activitiy

19

Long term responses to stress

Effects of mineralocorticoids (aldostrone)
- retention of sodium ions and water by kidneys
- increased blood volume and blood pressure

Effects of glucocorticoids (cortisol)
- proteins and fats broken down and converted to glucose, leading to increased blood glucose
- possible suppression of immune system

20

What are the three types of hormones? Are they hydrophillic and hydrophobic?

Polypeptides - hydrophillic, water-soluble


Steroids - hydrophobic, lipid-soluble

Amines - both: hydrophillic
hydrophobic

21

How does receptor location vary with hormone type?

Water-soluble hormones bind on membrane receptors.

Lipid-soluble hormones bind to a receptor in nucleus or cytoplasm (intracellular receptors) as they can cross the membrane.

22

What do thyroid hormones regulate?

- homeostatsis
- development

23

Positive vs negative feedback

positive - reinforces stimulus, takes to an extreme
negative - reduces stimulus, restores homeostasis

24

What is the point of feedback loops?

Feedback loops tell if things are back to normal or not.

25

Why must organisms maintain homeostasis?

Optimal enzyme activity is achieved within a very narrow range of conditions.

26

What molecules determine the tissue specificity of hormones?

Receptors

27

What gland secretes releasing hormones?

hypothalamus

28

Nonsteroid hormones vs steroid hormones

Nonsteroid hormones act via signal transduction pathways but steroid hormones do not.

29

Where are the receptors for nonsteroid hormones located?

In the cell's plasma membrane

30

A distinctive feature of the mechanism of action of thyroid hormones and steroid hormones is...

these hormones bind to receptors in the cell

31

What type of hormone is lipid soluble?

Steroid hormones

32

Where do steroid hormone-receptor complexes act?

In the nucleus

33

What is the primary reason for steroid hormones acting so slowly?

They turn genes on or off and it takes time for gene products to build up or become depleted.

34

Name the 11 peptide hormones (acronym)
Which are tropic and non-tropic? Which is both?

GH (T and NT)
Oxytocin (NT)
ADH (NT)
TSH (T)
FSH (T)
LH (T)
ACTH (T)
Prolactin (NT)
MSH (NT)
Insulin (NT)
Glucagon (NT)

35

Which two peptide hormones come from the posterior pituitary?

Oxytocin and ADH

36

What are the 6 steroid hormones? (acronym) Are they tropic or non-tropic?

Oestrogen
Mineralcorticoids
Androgens
Cortisol
Glucocorticoids
Progestins

All non tropic

37

Are steroid hormones water or lipid soluble? What about peptide hormones?

Steroids - lipid soluble
Peptides - water soluble

38

What are the 4 amine hormones? (acronym) Which are water soluble and which are lipid soluble? Which are tropic and which are non-tropic? Which is both?

Melatonin (lipid soluble) (T and NT)
Adrenaline (water soluble) (NT)
Noradrenaline (water soluble) (NT)
Thyroid hormones (lipid soluble) (T)

39

What is the acronym for peptide hormones? steroid hormones? amine hormones?

GOAT FLAP MIG
Occasionally Mum Actually Cooks Good Pies
MANT