Physiology #2

Question 1

When is flow through the coronaries highest?

Answer 1

during diastole

Question 2

Pathologic situations that interfere with CV system

Answer 2

• circulatory shock
• coronary artery disease
• acute coronary occlusion
• chronic heart failure
• HTN

Question 3

Circulatory shock

Answer 3

generalized, severe reduction in blood supply to body tissues –> metabolic needs are not met
BP usually low
Severe shock = inadequate flow to brain –> syncope

Question 4

Primary disturbances that cause circulatory shock

Answer 4

1. severely depressed myocardial function
2. grossly inadequate filling due to low mean circulatory pressure
3. profound systemic vasodilation

Question 5

Cardiogenic shock

Answer 5

cardiac pumping is compromised –> decreased CO

Question 6

Hypovolemic shock

Answer 6

depletion of body fluids –> decreased blood volume –> reduced cardiac filling –> reduced SV
ex. hemorrhage

Question 7

Anaphylactic shock

Answer 7

severe allergic reaction –> release of histamine and bradykinin –> decreased vasodilation –> increased permeability –> loss of venous tone –> decreased TPR and CO

Question 8

Septic shock

Answer 8

severe vasodilation due to release of substances by infective agents

Question 9

Neurogenic shock

Answer 9

loss of vascular tone due to inhibition of normal tonic activity of SNS –> vasodilation

Question 10

Compensatory response

Answer 10

essentially and increase in SNS activity attempting to reverse affects from the shock (moves flow away from organs that are a necessity)

Question 11

Decompensatory

Answer 11

bodily homeostasis deteriorates with prolonged exposure to reductions in blood flow –> adversely affects CV system –> leads to further reduction in flow
- can lead to progessive or irreversible shock

Question 12

Coronary Artery Disease

Answer 12

• leads to ischemia

- most common cause = atherosclerosis

Question 13

Acute Coronary Occlusion

Answer 13

MI!!

- acute interruption of coronary blood flow –> results in crisis

Question 14

Chronic Heart Failure

Answer 14

exists when ventricular function is depressed through myocardial damage, insufficient coronary flow, or anything that impairs performance

Question 15

Systolic Failure

Answer 15

EF < 40% –> heart is operating at lower than normal cardiac function curve
- reduced Ca2+ sequestration by SR, upregulation of NCX, low [Ca2+]
- decreased CO –> decreased BP
Long-Term Compensation
Pro- increased SNS –> rise in BP –> increased filling pressure
Con - fluid retention causes peripheral and CVP to be higher than normal –> elevated EDV –> dilation
- also affects organ function –> edema and congestion

Question 16

Main symptoms of systolic failure

Answer 16

inability to increase CO
- exercise intolerance, fatigue
Fluid accumulation
- tissue congestion, dyspnea, edema

Question 17

Diastolic dysfunction

Answer 17

stiffened heart during diastole –> increased filling pressure does not produce normal increases in EDV

Question 18

Hypertension

Answer 18

chronic elevation in arterial blood pressure
-Pulmonary (cor pulmonale) –> linked to chronic hypoxia
- Systemic - >140/90 –> increased risk of CAD, MI, heart failure
All forms require higher than normal arterial pressure to produce normal urine output rate

Question 19

Primary or Essential Hypertension

Answer 19

unknown cause (>90% of cases)

Question 20

Therapy for HTN

Answer 20

• reduce salt
• diuretics
• beta-blockers
• ACE inhibitors or ARBs