Week 1

Question 1

Autocrine Regulation

Answer 1

A cell communication mechanism in which the signalling molecules bind to receptors located on the cell secreting the signalling molecules

Question 2

What is an example of autocrine regulation

Answer 2

The regulation of somatostatin in the stomach

Question 3

Where is somastatin secreted from and what does it bind to

Answer 3

Secreted from D cells in the gastric glands.
Binds to SST2R receptors (on the D cells themselves)

Question 4

What happens when somastatin binds to SST2R receptors

Answer 4

Inhibits adenylyl cyclase > decreases cAMP > decreases gastric acid secretion from parietal cells

Question 5

What happens when somastatin binds to SST2R receptors on the D cells

Answer 5

A negative feedback loop is created and reduces somastatin receptors

Question 6

What is paracrine regulation

Answer 6

A cell communication mechanism in which the signalling molecules are secreted into the extracellular space and bind to receptors located on the adjacent cells without passing through the circulatory system

Question 7

What is an example of paracrine regulation

Answer 7

Histamine in the stomach

Question 8

What is histamine secreted by, and what does it bind to?

Answer 8

Enterochromaffin-like cells in the gastric glands, in response to stimulation by acetylcholine.
Binds to H2 receptors with subsequent activation of adenyl cyclase

Question 9

What does the action of histamine in the stomach via paracrine regulation cause?

Answer 9

An increase in cAMP, which increases the number of proton pumps, increasing gastric acid secretion from parietal cells

Question 10

what are parietal cells

Answer 10

The largest cells in the stomach glands (in the fundas and the body)

Question 11

What types of regulation are responsible for the release of gastric acid in the stomach?

Answer 11

Paracrine , endocrine and neural pathways (synaptic transmission)

Question 12

Neurotransmitter

Answer 12

A chemical substance released from a neutron to bring about the transfer of an impulse to another neuron

Question 13

Name some common neurotransmitters

Answer 13

Acetylcholine
Adrenaline
Dopamine
Glycine
Histamine
Noradrenaline
Serotonin
Glutamate
GAMA

Question 14

What is endocrine regulation

Answer 14

A cell communication mechanism in which the signalling molecules are secreted from cells located in secretory glands into the circulatory system. Allowing for the signalling molecules to travel over a relatively large distance, eventually binding to receptors located on/in cells of a target organ/tissue

Question 15

What is an example of endocrine communication

Answer 15

The hypophyseal portal system.
Hormones such as ACTH are secreted from the pituitary glands into the connected circulatory vasculature.

Question 16

Actions of Cortisol

Answer 16

Maintains blood pressure
Facilitated stress response
Immune system suppression
Protein breakdown and liberation of fatty acids
Stimulates gluconeogenesis in the liver

Question 17

Ligand-gated Ion Channels

Answer 17

Response occurs in miliseconds
Hyperpolarisation or depolarisation of ions
E.g. nicotinic or ACh receptor

Question 18

G protein-coupled receptors

Answer 18

Response occurs in seconds
Ions go through change in excitability
E.g. Muscarinic, ACh receptor

Question 19

Kinase-linked receptors

Answer 19

Response in hours
Ions go through protein phosphorylation > gene transcription > protein synthesis
E.g. cytokine receptors

Question 20

Nuclear receptors

Answer 20

Response in hours
Receptor in the nucleus to then activate gene transcription > protein synthesis
E.g. Oestrogen receptor

Question 21

Nicotinic acetylcholine receptors

Answer 21

Permeable to Na+, K+ and Ca2+
Non-specific cation channels
Modulate fast synaptic excitation

Question 22

Intracellular receptors

Answer 22

Protein monomers located in the nucleus of the target cell and contain DNA-binding domains, allowing for the control for gene transcription.

Question 23

Are steroid hormones hydrophilic/lipophilic or hydrophobic/lipophobic and can they pass through plasma membrane

Answer 23

Steroid hormones are lyophilic/lipophilic and can pass through the plasma membrane

Question 24

When the steroid hormones pass through the plasma membrane what 2-step process occurs?

Answer 24

Activated hormone-receptor complex forms within the cell
The complex binds to DNA and activates specific genes
- gene activation leads to production of key proteins