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Flashcards in CVS case study questions Deck (11):
1

What causes the peak of depolarisation at the start?

Influx of Na+
- T tubule membrane depolarised

2

What ion is most important for standing membrane potential?

K+

3

What happens to force of contraction when there is sympathetic stimulation of the heart? and why?

INCREASEs
- due to increases in CO and HR.
- The activity causes faster depolarisation of the SAN causing a faster HR.
- This is caused by the noradrenaline binding to beta 1 adrenergic receptors causing cAMP increase, activating PKA.
- This then phosphorylates the L-type channels and the SR releases channels.
- Ergo, this leads to an increased (ca) binding to troponin C, and therefore more cross bridges form.

4

What occurs in exercise to lead to an increase in CO?

Activity of skeletal muscles, leading to increased venous tone, pressure and return.
- This increases the EDV, preload and the SV.
- This increases CO, causing increased sympathetic activity and adrenaline, and increased venoconstriction and HR.

5

Why does venous return lead to increased CO?

Increased venous return, more blood to atria, increased EDV, increase preload, increased SV (due to Starling's law) causing increased CO.

6

State 2 "western" lifestyle factors that contribute to atherosclerosis

Smoking and Obesity

7

Name 2 of the 3 cells involved in atherosclerosis

- Vascular smooth muscle cells
- Macrophages
- Vascular endothelial cells

8

Name 2 non-modifiable risk factors for atherosclerosis

- Age
- Race
- Gender

9

Describe 3 ways in which changes in arterial wall in atherosclerosis can lead to clinical problems

- Embolism: occlusion of a small vessel at a distant site
- Thrombosis
- Stenosis

10

Name 2 ways in which vascular smooth muscle cells contribute to the stability of the plaque

- Increases collagen synthesis, forming a fibrous cap, increased matrix deposition.
- Increased thickness of the smooth muscle around the plaque to prevent rupture.

11

Aside from skeletal muscle, name 2 other vascular beds to which vasodilation occurs in exercise

- Coronary vessels
- Bronchial mucosa etc