Endocrine Intro & Appetite

Question 1

What group or neurones are responsible for controlling the “biological click”

Answer 1

Suprachiasmatic nucleus

Question 2

What are zeitgebers?

Answer 2

Cues from environment to keep the body on 24 hour cycle. Temp, light, social interaction, exercise.

Question 3

Melanin is also involved in setting the biological clock. Which gland is it secreted by?

Answer 3

Pineal gland

Question 4

When are positive feedback loops used?

Answer 4

When rapid change needed - blood clotting, ovulation.

Question 5

Which receptors measure osmotic pressure in the hypothalamus?

Answer 5

Osmoreceptors

Question 6

What will happen to cells if blood osmolality increases?

Answer 6

Hypertonic solution. Cells will lose water to extracellular environment and shrink.

Question 7

Where is ADH secreted from?

Answer 7

ADH

Question 8

Where is ADH secreted?

Answer 8

Hypothalamus

Question 9

How does the body respond to increased blood osmolality?

Answer 9

Osmoreceptors in hypothalamus detect change and trigger ADH release and thirst.

Question 10

How does the body respond to a decrease in blood osmolality?

Answer 10

Osmoreceptors detect change and decrease ADH secretion from posterior pituitary, this leads to less water reabsorption in the kidney.

Question 11

How do the endocrine and nervous system differ in terms of speed of control?

Answer 11

Endocrine = slow

Nervous system = fast

Question 12

What hormones are peptide/polypeptide?

Answer 12

Insulin, glucagon, growth hormone

Question 13

What hormones are amino acid derivatives (amines)?

Answer 13

NA and arenaline, dopamine, thyroid hormones, melatonin

Question 14

What hormones are glycoproteins?

Answer 14

TSH, FSH, LH

Question 15

What is the precursor for steroid hormone synthesis?

Answer 15

Cholesterol

Question 16

Which hormones are steroid hormones?

Answer 16

Aldosterone, cortisol, testosterone, progesterone

Question 17

What roles do hormone carrier proteins have?

Answer 17

• Increase solubility of hormone in plasma
• Increase half life
• Readily accessible reserve

Question 18

What type of receptor does adrenaline bind to?

Answer 18

GPCR

Question 19

What type of receptor does insulin bind to?

Answer 19

Tyrosine kinase

Question 20

What receptors can lipid soluble hormones bind to?

Answer 20

1. Cytoplasmic receptors, binds and enters nucleus

2. Pre-bound receptor on DNA

Question 21

Give an example of a hormone that binds to a pre-bound receptor on DNA hormone response element.

Answer 21

Thyroid hormone.

Question 22

What group of hypothalamic neurones are involved in controlling appetite?

Answer 22

Arcuate nucleus

Question 23

What 2 types of primary neurones signal to the arcuate nucleus?

Answer 23

1. Stimulatory neurones

2. Inhibitory neurones

Question 24

What neurotransmitters are present in primary stimulatory neurones?

Answer 24

Neuropeptide Y (NPY)
Agouti-related peptide (AgRP)

Question 25

What do stimulatory neurones do?

Answer 25

Promote hunger

Question 26

What neurotransmitters are present in primary inhibitory neurones?

Answer 26

POMC which yields alpha-MSH and beta-endorphin.

Question 27

What do inhibitory neurones do?

Answer 27

Promote satiety

Question 28

What hormone is released from the stomach wall when the stomach is empty, what effect does it have?

Answer 28

Ghrelin - stimulates excitatory primary neurones in arcuate nucleus

Question 29

Which hormone is released by cells in the ileum and cool in response to feeding?

Answer 29

PYY (peptide-tyrosine-tyrosine)

Question 30

What effect does PYY have?

Answer 30

Inhibits excitatory neurones of arcuate nucleus | Stimulates inhibitory neurones to suppress appetite.

Question 31

Which hormone signals travel from the gut to the hypothalamus to influence hunger?

Answer 31

Ghrelin - stomach | PYY (ileum and colon)

Question 32

Which hormones signal from the body to the hypothalamus in appetite regulation?

Answer 32

Leptin, insulin, amylin

Question 33

What is leptin produced by?

Answer 33

Adipocytes

Question 34

What 2 effects does leptin have on the arcuate nucleus?

Answer 34

Suppresses appetite: 1. Stimulates inhibitory neurones 2. Inhibits excitatory neurones

Question 35

How does leptin influence heat generation?

Answer 35

Induces expression of uncoupling proteins in mitochondria to increase energy loss as heat.

Question 36

How does insulin influence appetite?

Answer 36

Stimulates inhibitory neurones to suppress appetite. | Less important that leptin.

Question 37

Where is amylin secreted from?

Answer 37

Beta cells in the pancreas

Question 38

What effect does amylin have on appetite?

Answer 38

Suppresses appetite | Decreases glucagon secretion, slows gastric emptying.

Question 39

Do the units mOsmol/L refer to the osmolality or osmolarity of the solution?

Answer 39

Osmolarity

Question 40

A solution of normal saline has a concentration of 308 mOsmol/L (9.0g per litre). What concentration of Na+ ions would be in this solution?

Answer 40

154 mmol/L

Question 41

In which region of the brain are the osmoreceptors located?

Answer 41

Hypothalamus

Question 42

Which class of hormone does thyroid hormone fall under?

Answer 42

Amine hormone

Question 43

Name the peptide precursor of the neurotransmitters αMSH, β-endorphin and ACTH.

Answer 43

POMC