EH 9 Intro To Endocrine System And Appetite

Question 1

Homeostasis definition

Answer 1

The maintenance of a stable environment within a dynamic equilibrium using negative feedback systems

Question 2

Features of a control system

Answer 2

1- stimulus
2- receptors
Afferent pathway
3- control centre
Efferent pathway
4- effector
Negative feeback

Question 3

What detects position and movement?

Answer 3

Proprioreceptors

Question 4

What detects dangerous stimuli?

Answer 4

Nociceptors

Question 5

What does the control centre do and where is it located?

Answer 5

Hypothalamus + pituitary gland
Determines set point
Analyses afferent input
Determines response

Question 6

How do biological rhythms arise?

Answer 6

Set points varying over time

Question 7

What is the suprachiasmatic nucleus and what does it set?

Answer 7

Biological clock in hypothalamus
Sets the circadian/diurnal rhythm

Question 8

What does melatonin set and where is released from?

Answer 8

Circadian/diurnal rhythm
Pineal gland

Question 9

What are zeitgebers?
Examples

Answer 9

Environmental cues
Examples: lights, temp, exercise

Question 10

Hormone definition

Answer 10

Molecule secreted by endocrine gland into bloodstream to act on distant target cells

Question 11

What conc. are horomones in the blood?

Answer 11

Very low concentration

Question 12

Four classifications of hormones

Answer 12

Peptide
Glycoproteins
Amino acid devrivatives
Steroids

Question 13

What classifications of hormones are water soluble/

Answer 13

Glycoproteins
Peptide
Some amino acid derivative - (nor)adrenaline

Question 14

What classifications of hormones are lipid soluble?

Answer 14

Steroids
Some amino acid derivatives-thyroid hormone

Question 15

Describe peptide hormones + examples

Answer 15

Water soluble
Free in plasma
Examples: insulin, glucagon growth hormone

Question 16

Describe Glycoproteins hormones + examples

Answer 16

Water soluble
Free in plasma
Examples- LH, FSH, TSH

Question 17

Describe Amino acid derivatives hormones + examples

Answer 17

• (Nor)adrenaline - water soluble - free in plasma
• Thyroid horomone - lipid soluble - bound to carrier protein TBG
• melatonin

Question 18

Describe Steroid hormones + examples

Answer 18

Lipid soluble
Derived from cholesterol
Bound to carrier proteins
Examples- cortisol, aldosterone, testosterone, oestrogen

Question 19

How are water soluble hormones transported in the blood?

Answer 19

Free in plasma

Question 20

How are lipid soluble hormones transported in blood?

Answer 20

Bound to carrier proteins

Question 21

Role of carrier proteins

Answer 21

Increase solubility of hormone in plasma
Transports lipid soluble hormones in blood
Increase half life
Readily accessible reverse

Question 22

Endocrine communication

Answer 22

Hormone released into blood and carried to distant target cells

Question 23

Neurocrine communication

Answer 23

Hormone transported down axon from neurone + released into blood to distant target cell

Question 24

Paracrine communication

Answer 24

Hormone carried short distance to adjacent ell via interstitial fluid

Question 25

Autocrine communication

Answer 25

Hormone acts back on original cell

Question 26

In what type of communication does the hormone act back on original cell?

Answer 26

Autocrine

Question 27

In what type of communication does the hormone act on adjacent cells via interstitial fluid?

Answer 27

Paracrine

Question 28

In what communication does the hormone travel down the axon from the neurone?

Answer 28

Neurocrine

Question 29

In what communication does the horomone travel in the blood to distant target cells?

Answer 29

Endocrine Neurocrine

Question 30

Factors determining hormone levels

Answer 30

- **rate of production** - synthesis and secretion - **rate of delivery** - increased blood flow = increased hormone delivers - **rate of degradation** - metabolism + excretion

Question 31

Are lipid or water hormone receptors faster?

Answer 31

Water- triggers mechanism already set out

Question 32

Where do water soluble hormones bind to?

Answer 32

Can’t pass through plasma membrane Bind to extra cellular/cell surface receptors

Question 33

Two extracellular receptors

Answer 33

G protein coupled receptor Tyrosine kinase

Question 34

How does G protein coupled receptor initiate a response?

Answer 34

1- binding of hormone to receptor 2- dissociation of G protein alpha subunit 3- activation of effector protein 4- formation of secondary messenger 5- activation of protein kinase 6-phosphorylation of target proteins 7- cellular response

Question 35

How does tyrosine kinase initiate a response?

Answer 35

1- hormone binds to receptor 2- dimerisation 3- autophosphorylatio of tyrosines 4- activation of protein kinase 5- phosphorylation of target protein 6- cellular response

Question 36

What receptors do lipid soluble hormones bind to?

Answer 36

Can pass through plasma membrane Bind to intracellular receptors in cytoplasm or nucleus Modulate gene transcription

Question 37

How to lipid soluble hormones initiate a response?

Answer 37

1- hormone bind to receptor 2- receptor bind to DNA sequence with HRE- hormone response element 3- expression of new protein mediates effect of hormone DNA > mRNA > new protein > cellular response

Question 38

What is the appetite control centre?

Answer 38

Arcuate nucleus

Question 39

What controls the feeling of fullness?

Answer 39

Satiety centre

Question 40

Where is the satiety centre?

Answer 40

Hypothalamus

Question 41

Nuclei meaning in hypothalamus

Answer 41

Several clusters of neurones

Question 42

What do excitatory/stimulators neurones in the arcuate centre do?

Answer 42

Promote hunger Via NPY and AgRP

Question 43

What does the inhibitory neurone in the arcuate centre do?

Answer 43

Suppresses appetite Via release of POMC > alpha MSH and beta endorphin Promote satiety

Question 44

What do primary neurones on the arcuate centre do?

Answer 44

Sense metabolite and hormone levels

Question 45

What do secondary neurones do?

Answer 45

Receive inputs from primary neurones Co-ordinate an appropriate response via vagus nerve

Question 46

What nerve do secondary neurones express a response via?

Answer 46

Vagus nerve

Question 47

What hormone stimulates appetite?

Answer 47

Ghrelin - ‘growling’

Question 48

What hormones suppress appetite?

Answer 48

PYY - peptide tyrosine tyrosine Leptin Insulin Amylin

Question 49

Ghrelin

Answer 49

Stimulates appetite Released from stomach wall when empty Filling of stomach inhibits release

Question 50

Ghrelin effect on arcuate nucleus

Answer 50

Stimulates excitatory neurones Stimulates appetite

Question 51

Peptide tyrosine tyrosine PYY

Answer 51

Suppresses appetite Released by ileum and colon - small intestine

Question 52

PYY effect on arcuate nucleus

Answer 52

Stimulates inhibitory neurones Inhibits excitatory neurones

Question 53

Leptin

Answer 53

Suppresses appetite Released into blood by adipocytes

Question 54

Leptin effect on arcuate nucleus

Answer 54

Stimulates inhibitory neurones Inhibits excitatory neurones

Question 55

Insulin

Answer 55

Suppresses appetite Released by beta cells in pancreas

Question 56

Amylin

Answer 56

Suppresses appetite Released by beta cells in pancreas Decrease glucagon secretion Slows gastric emptying

Question 57

When is are cortisol levels at the highest?

Answer 57

8am

Question 58

What hormones effect appetite from the gut?

Answer 58

Ghrelin - stimulates PYY - suppresses

Question 59

What hormones effect appetite from the body?

Answer 59

Leptin Amylin Insulin Suppress appetite