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

What causes the peak of depolarisation at the start?

A

Influx of Na+

- T tubule membrane depolarised

2
Q

What ion is most important for standing membrane potential?

A

K+

3
Q

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

A

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
Q

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

A

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
Q

Why does venous return lead to increased CO?

A

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

6
Q

State 2 “western” lifestyle factors that contribute to atherosclerosis

A

Smoking and Obesity

7
Q

Name 2 of the 3 cells involved in atherosclerosis

A
  • Vascular smooth muscle cells
  • Macrophages
  • Vascular endothelial cells
8
Q

Name 2 non-modifiable risk factors for atherosclerosis

A
  • Age
  • Race
  • Gender
9
Q

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

A
  • Embolism: occlusion of a small vessel at a distant site
  • Thrombosis
  • Stenosis
10
Q

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

A
  • Increases collagen synthesis, forming a fibrous cap, increased matrix deposition.
  • Increased thickness of the smooth muscle around the plaque to prevent rupture.
11
Q

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

A
  • Coronary vessels

- Bronchial mucosa etc