Appetite

Question 1

What are the 3 factors control thirst

Answer 1

Body fluid osmolality
Blood volume is reduced
Blood pressure is reduced

Question 2

What is the most potent stimulus in controlling thirst

Answer 2

Plasma osmolality

Question 3

What % change in plasma osmolality is needed to induce a desire to drink?

Answer 3

2-3

Question 4

What % change in blood vol or arterial pressure is needed to induce a desire to drink?

Answer 4

10-15

Question 5

What is the other name for ADH?

Answer 5

Vasopressin

Question 6

What does ADH act on?

Answer 6

Collecting duct in kidney

Question 7

What happens to urine volume when ADH is low? What is this called

Answer 7

Vol of urine excreted is large

This is called water diuresis

Question 8

What happens to urine volume when ADH is high? What is this called

Answer 8

Vol of urine excreted is small

This is called anti diuresis

Question 9

What type of receptor are osmoreceptors?

Answer 9

Sensory

Question 10

Where are osmoreceptors found?

Answer 10

In the hypothalamus in the organum vasculosum and subfornical organ

Question 11

How do osmoreceptors cause ADH release?

Answer 11

When plasma is more concentrated cells shrink
Proportion of cation channels increases (membrane depolarises)
This sends signals to the ADH producing cells to increase ADH
This causes fluid retention and involves drinking

Question 12

Where are receptors involved in short term relief of thirst found?

Answer 12

Mouth
Pharynx
Oesophagus

Question 13

When is thirst completely satisfied?

Answer 13

Once plasma osmolality is decreased or blood volume or arterial pressure corrected

Question 14

What cells in the renin angiotensin system detect a fall in BP?

Answer 14

Juxtoglomerular cells

Question 15

Where are juxtoglomerular cells found?

Answer 15

Renal afferent arterioles

Question 16

What does fall in BP stimulate from juxtoglomerular cells?

Answer 16

Angiotensin release

Question 17

What is angiotensin also known as?

Answer 17

Renin

Question 18

What is angiotensin converted to in the liver and how?

Answer 18

Angiotensin I via angiotensinogen

Question 19

What is angiotensin I converted to in the lungs and how?

Answer 19

Angiotensin II via ACE

Question 20

What are the conversion steps to go from angiotensin to angiotensin II (include enzymes and locations)

Answer 20

In the liver angiotensin is converted to angiotensin I via angiotensinogen

In the lungs angiotensin I is converted to angiotensin II via ACE

Question 21

What are the effects of angiotensin II?

Answer 21

Vasoconstriction via increased sympathetic activity
Thirst
Aldosterone release from the zona glomerulosa of the adrenal cortex
Aldosterone causes water retention via sodium and chloride absorption and potassium secretion
ADH secretion

Question 22

What happens in an overfed or weight augmented state?

Answer 22

Increased sympathetic nervous system activity
Increased energy expenditure
Reduced hunger/good intake

Question 23

What happens in an underfed or weight reduced state?

Answer 23

Decreased sympathetic nervous system activity
Decreased energy expenditure
Increased hunger/good intake
Reduced thyroid function

Question 24

What substances are appetite stimulants?

Answer 24

Orexigenic

Question 25

What structure in the brain is important for appetite regulation?

Answer 25

Hypothalamus

Question 26

What substances are appetite suppressants?

Answer 26

Anorectic

Question 27

What is the arcuate nucleus and what is its role?

Answer 27

Brain area involved in the regulation of food intake It has an incomplete blood brain barrier, allows access to peripheral hormones. Integrates peripheral and central feeding signals

Question 28

What does the stimulatory neuronal population involve?

Answer 28

NPY/Agrp

Question 29

What does the inhibitory neuronal population involve?

Answer 29

POMC

Question 30

If feeding needs to be increased what in the arcuate nucleus is involved?

Answer 30

NPY/Agrp neurons

Question 31

If feeding needs to be decreased what in the arcuate nucleus is involved?

Answer 31

POMC

Question 32

Where do NPY/Agrp and POMC act?

Answer 32

On the paraventricular nucleus

Question 33

What are melanocortins a product of?

Answer 33

The POMC chain

Question 34

What receptors in the hypothalamus when stimulated lead to reduction in appetite?

Answer 34

Melanocortin 4 receptors

Question 35

What can POMC and MC4-R deficiency cause?

Answer 35

Morbid obesity

Question 36

Are mutations responsible for the prevalence of obesity?

Answer 36

No they just help explain signalling

Question 37

How does the vagus nerve feedback in terms of appetite?

Answer 37

It feedsback to the brainstem which then can go hypothalamus

Question 38

What is adipostat?

Answer 38

This is a circulating hormone produced by fat

Question 39

What may misregulation of the adipostat mechanism lead to?

Answer 39

Obesity

Question 40

How does adipostat affect food intake?

Answer 40

Hypothalamus senses the concentration of hormone | and then alters neuropeptides to increase or decrease food intake

Question 41

What makes leptin?

Answer 41

Adipocytes in white adipose tissue

Question 42

What is leptin and what does it do?

Answer 42

A hormone that decreases appetite

Question 43

What happens to leptin level as body weight rises?

Answer 43

It also rises

Question 44

What are the ways by which the mechanism of action of leptin can be disrupted?

Answer 44

Insufficient production Defect in receptor signalling Decreased sensitivity to leptin

Question 45

How effective is leptin as weight control drug?

Answer 45

Not effective

Question 46

What 2 main hormones secreted by enteroendocrine cells regulate appetite?

Answer 46

Ghrelin and peptide YY

Question 47

What 2 main hormones are involved with short term regulation of appetite?

Answer 47

Ghrelin and peptide YY

Question 48

Where are ghrelin and peptide YY produced?

Answer 48

Enteroendocrine cells in the stomach, pancreas & SB

Question 49

When are ghrelin levels highest? Why?

Answer 49

Before a meal as it helps prepare for food intake by increasing gastric motility and acid secretion

Question 50

What does ghrelin stimulate and inhibit?

Answer 50

Stimulates NPY/Agrp neurons | Inhibits POMC neurons

Question 51

What does ghrelin do to appetite?

Answer 51

Increases it

Question 52

When and where is PYY released?

Answer 52

Released in the terminal ileum (TI) and colon in response to feeding (when food arrives in those areas)

Question 53

What does PYY do to appetite?

Answer 53

Reduced it

Question 54

What does PYY stimulate and inhibit?

Answer 54

Stimulates POMC neurons | Inhibits NPY/Agrp neurons

Question 55

Define polydipsia

Answer 55

Excessive thirst or excess drinking

Question 56

Define adipsia

Answer 56

Inappropriate lack of thirst with consequent failure to drink in order to correct hyperosmolality

Question 57

Define anorexia

Answer 57

Lack or loss of appetite for food

Question 58

What is the difference between anorexia and anorexia nervosa?

Answer 58

Anorexia nervosa is the psychological condition | Anorexia is just a loss of appetite for food, it can be a result of other physiological conditions

Question 59

What are the 2 classes of thirst disorders?

Answer 59

Polydipsic | Adipsic

Question 60

What are the types of polydipsia or adipsia?

Answer 60

Primary or secondary

Question 61

What are some causes of secondary polydipsia

Answer 61

Chronic conditions (eg diabetes, kidney failure, Conn's, Addison's, sickle cell) Medications (diuretics, laxatives, antidepressants) Dehydration (acute ilnness, sweating, fevers, vomitting, diarrhoea)

Question 62

What is the difference between diabetes insipidus and mellitus?

Answer 62

``` Mellitus= problems with insulin and blood glucose Insipidus= problems with ADH and water regulation ```

Question 63

What are the main conditions that can cause polydipsia asides from diabetes?

Answer 63

Acute kidney failure Conn’s syndrome (primary aldosteronism) Addison's disease (hypoadrenocorticism)

Question 64

What are some causes of primary polydipsia?

Answer 64

Mental illness (psychogenic, schizophrenia, mood disorders, anorexia, drug use) Brain injury Organic brain damage

Question 65

How many types of adipsia are there? Which is most common?

Answer 65

There are 4 types (A, B, C and D) and A is the most common

Question 66

Define the term eating disorders

Answer 66

Mental disorders defined by abnormal eating habits

Question 67

What disorders do eating disorders encompass?

Answer 67

``` Binge eating disorder Anorexia nervosa Bulimia nervosa Pica Rumination syndrome Avoidant/restrictive food intake disorder ```

Question 68

What is pica?

Answer 68

People eat non food items of no nutritional value eg hair, paint chips

Question 69

What is rumination syndrome and how is it different to bullimia nervosa?

Answer 69

It is a condition where people regurgitate food that is undigested and not acidic, in bullimia nervosa food is digested and acidic and regurgitation involves cycles of binging and purging

Question 70

What are some signs of eating disorders?

Answer 70

``` Low BMI Continuous weight loss Amenorrhea Halitosis Mood swings Dry hair, skin & hair thinning ```

Question 71

What is the BMI range for mild anorexia?

Answer 71

over 17

Question 72

What is the BMI range for moderate anorexia?

Answer 72

16-16.99

Question 73

What is the BMI range for severe anorexia?

Answer 73

15-15.99

Question 74

What is the BMI range for extreme anorexia?

Answer 74

less than 15

Question 75

Out of diet and exercise, what is most effective for weight reduction in obesity?

Answer 75

Diet more than exercise but a combination of both is best

Question 76

What happens to ghrelin, GLP1, GLP2 and PYY after bariatric surgery?

Answer 76

Ghrelin reduces | GLP1, GLP2 and PYY increase

Question 77

What commonly presents with gingival bleeding?

Answer 77

Scurvy