Physiology Flashcards

1
Q

what extrinsic mechanisms increase stroke volume

A
  1. sympathetic system on heart
  2. sympathetic system on venous return
  3. skeletal muscle pump
  4. thoracic pump
  5. increased activity in the RAAS
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

what are the molecular mechanisms by which the sympathetic system increases stroke volume

A
  1. activation of beta 1 adrenergic receptors on the ventricles
  2. increased cAMP
  3. increase in PKA
  4. phosphorylation of L type ca2+ channels allowing increased ca2+ entry
  5. constriction of veins through the activation of alpha 1 adrenergic receptors
    - increases IP3 which leads to an increase in conc of Ca2+, leading to increase in Ca2+ calmodulin, activation of MLCK and phosphorylation of MLC which causes contraction of smooth muscle
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

name 2 systems that can regulate total peripheral resistance

A
  • sympathetic system

- RAAS

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

describe the mechanism of action of the sympathetic system in regulating total peripheral resistance

A
  1. either activates alpha 1 adrenergic receptors to cause an increase in TPR
  2. or activates beta 2 adrenergic receptors to cause a decrease in TPR via an increase in cAMP, increase in PKA and phosphorylation of MLCK which inhibits its action so smooth muscle relax
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

describe the mechanism of action of RAAS in regulating total peripheral resistance

A
  1. RAAS increases TPR by the actions of AngII on AT1 receptors
    - increases IP3
    - increases intracellular Ca2+
    - increases ca2+ calmodulin
    - increases activation of MLCK
    - increases phosphorylation of MLC
    - increases smooth muscle contraction
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

which hypertensive would be frontline treatment for a black person of African or Caribbean origin

A

calcium channel blocker

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

which antihypertensive would be frontline treatment for a British Indian patient aged 45 years old with no other comorbidities

A

ACE inhibitors

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

which antihypertensive would be frontline treatment for a patient aged 45 years old with hypertension and benign prostatic hypertrophy

A

alpha 1 antagonist

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

why do ACE inhibitors cause a cough in about 20% of patients

A

they inhibit the breakdown of bradykinin which can then activate sensory nerves in the airways to cause the cough

How well did you know this?
1
Not at all
2
3
4
5
Perfectly