PSC1002/L01 Homeostasis

Question 1

Give 3 things that are controlled by homeostasis.

Answer 1

Internal environment (ECF)
Equilibrium through compensation
Variables (bp)

Question 2

Define negative feedback.

Answer 2

Effector leads to reduction in stimulus

Question 3

Give 2 physiological examples of negative feedback.

Answer 3

Blood pressure
Plasma osmolarity
Pupil diameter

Question 4

What 2 muscles work to constrict/dilate pupil diameter?

Answer 4

Sphincter pupillae
Dilator pupillae

Question 5

What 3 control centres make up the autonomic nervous system?

Answer 5

Hypothalamus
Brain stem
Spinal cord

Question 6

What kind of nerve fibres are in the autonomic nervous system?

Answer 6

Sensory Afferent Nerve Fibres

Question 7

What 2 efferent pathways make up the autonomic nervous system?

Answer 7

Sympathetic - fight or flight
Parasympathetic - rest and digest

Question 8

Name the common features of the 2 efferent pathways. (4)

Answer 8

2 neurons in series
Preganglionic neurons originate in CNS
Postganglionic neurons originate in autonomic ganglia
1 preganglionic neuron can synapse with many postganglionic neurone

Question 9

Give 3 examples of effects of the parasympathetic nervous system.

Answer 9

Constricts pupil
Stimulates salivation
Inhibits heart
Constricts bronchi
Stimulates digestive activity
Stimulates gallbladder
Contracts bladder
Relaxes rectum

Question 10

Give 3 examples of effects of the sympathetic nervous system.

Answer 10

Dilates pupil
Inhibits salivation
Relaxes bronchi
Accelerates heart
Inhibits digestive activity
Stimulates glucose release by liver
Secretion of epinephrine from kidney
Relaxes bladder
Contracts rectum

Question 10

What hormones are involved in flight or fight response? (4)

Answer 10

Adrenaline
Noradrenaline
Cortisol
Potentially osteocalcin

Question 11

Describe the osteocalcin pathway of flight or fight response. (5)

Answer 11

Stimulus -> amygdala centre -> bone osteoblasts -> osteocalcin -> inhibits PNS

Question 12

Describe the preganglionic origin of the cranial nerve III (oculomotor).

Answer 12

Eye

Question 13

Describe the preganglionic origin of the cranial nerve VII (facial). (3)

Answer 13

Lacrimal
Nasal
Submandibular

Question 14

Describe the preganglionic origin of the cranial nerve IX (glossopharyngeal).

Answer 14

Parotid

Question 15

Describe the preganglionic origin of the cranial nerve X (vagus). (2)

Answer 15

Thorax
2/3 abdomen (75%)

Question 16

Describe the origin of the pelvic nerve.

Answer 16

Rectum
Bladder

Question 17

Describe the length of neurons in the parasympathetic nervous system.

Answer 17

Preganglionic = long
Postganglionic = short

Question 18

Describe the length of neurons in the sympathetic nervous system.

Answer 18

Preganglionic = short
Postganglionic = long

Question 19

Describe the preganglionic origin of the sympathetic nervous system.

Answer 19

Thoracic T1 - Lumbar 2/3 (L2/3)

Question 20

Describe the postganglionic origin of the sympathetic nervous system.

Answer 20

2 paravertebral sympathetic chains

Question 21

What is special about innervation of the adrenal medulla?

Answer 21

Directly innervated by preganglionic neuron of the SNS

Question 22

Give 4 neurotransmitters of the ANS.

Answer 22

Acetylcholine
Noradrenaline
Adrenaline
Non-adrenergic, non-cholinergic neurotransmitters (NANC)

Question 23

What 2 kinds of receptors are found in the ANS?

Answer 23

Cholinergic
Adrenergic

Question 24

Give 3 features of nicotinic receptors.

Answer 24

In ganglia SNS & PNS Neuromuscular junction Blocked by curare

Question 25

Give 2 features of muscarinic receptors.

Answer 25

Target organs in PNS Blocked by atropine

Question 26

Give an exception to muscarinic receptors in target organ PNS.

Answer 26

Sweat gland innervation by SNS

Question 27

What is attached to muscarinic receptors?

Answer 27

G-protein

Question 28

What is attached to a nicotinic receptor?

Answer 28

Alpha and beta component

Question 29

Describe the action of alpha1 postsynaptic receptors.

Answer 29

NAdr > Adr Vasoconstriction and smooth muscle contraction

Question 30

Describe the action of alpha2 presynaptic receptors.

Answer 30

NAdr > Adr Reduction in adrenergic and cholinergic transmission

Question 31

What are alpha receptors blocked by?

Answer 31

Phentolamine

Question 32

Describe the action of beta1 receptors.

Answer 32

Adr = NAdr Increase in heart rate and force of contraction

Question 33

Describe the action of beta2 receptors.

Answer 33

Adr > NAdr Vasodilation and smooth muscle relaxation

Question 34

What compounds block beta receptors?

Answer 34

Propanolol

Question 35

What is associated with adrenoreceptors?

Answer 35

G-protein