Session 4 Flashcards Preview

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Flashcards in Session 4 Deck (15):
1

What are the basic features of the parasympathetic nervous system?

- Long pre-ganglionic neurone and short post-ganglionic neurone
- Pre-ganglionic neurone is cholinergic
- Post-ganglion if neurone is cholinergic

2

What is the effect of the SNS on the heart and which receptors are acted on?

- Increased heart rate and force of contraction
- Acts on beta1 receptors

3

What effect does the PNS have on the heart and which receptor does it act on?

- Decreased heart rate
- Acts on M2 receptors

4

What effects does the SNS have on airways and which receptors are acted on?

- Relaxes airways
- Acts on beta2 receptors

5

What effects does the PNS have on the airways?

- Contracts the airway
- Acts on M3 receptors

6

What effects does the SNS have on the pupils and which receptors are acted on?

- Dilates pupils
- Acts on alpha1 receptors

7

What effects does the SNS have on sweat glands and which receptors are acted on?

- Localised secretion when alpha1 receptors are acted on
- General secretion when M3 receptors are acted on

8

What effects does the PNS have on the pupils and which receptors are acted on?

- Constricts pupils
- Acts on M3 receptors

9

What effects does the PNS have on sweat glands and what receptors are acted on?

No effects

10

What effects does the SNS have on smooth muscle in the walls of arteries, arterioles and veins (excluding specialised vessels) and which receptors are used?

- Constriction of the smooth muscle causing vasoconstriction
- Via alpha1 adrenoceptors

11

How is sympathetic outflow to blood vessels controlled?

Controlled from the brain stem via the vasomotor centres in the medulla oblongata using information from baroreceptors in the aortic arch and carotid sinuses

12

What is the intrinsic heart rate (I.e. If all autonomic inputs are blocked)?

100bpm

13

What causes the normal resting heart rate of ~60bpm?

Intrinsic rate is reduced because parasympathetic input dominates over sympathetic input at rest

14

How is force of contraction of the heart controlled?

Sympathetic nerve fibres innervate ventricular cardiac myocytes to control force of contraction

15

What are the basic features of the sympathetic nervous system?

- Thoracodorsal-lumbar outflow (T1-L2)
- Short pre-ganglionic neurone and long post-ganglionic neurone
- Pre-ganglionic neurone is cholinergic
- Post-ganglionic neurone is noradrenergic
- Synapse at the same level or a different level as the origin but not in the paravertebral chain