Chapter 14

Question 1

Cardiac output

Answer 1

Volume of blood pumped per minute by each ventricle

Question 2

CO equation

Answer 2

Stroke volume x heart rate
Average: 5,500 ml/minute

Question 3

Sympathetic effects on HR

Answer 3

Norepenephrine and adrenal epinephrine keep HCN channels open (which allows na+ in) increasing heart rate

Question 4

Parasympathetic effects on HR

Answer 4

Acetylcholine opens K+ channels slowing heart rate

Question 5

Regulation of cardiac rate

Answer 5

Cardiac control center of medulla regulates this

Question 6

3 variables regulating stroke volume

Answer 6

EDV, TPR, and contractility

Question 7

EDV

Answer 7

Volume of blood in the ventricles at the end of diastole aka preload
When this increases stroke volume increases

Question 8

Total peripheral resistance

Answer 8

Frictional resistance to blood flow in the arteries aka afterload
Inversely related to stroke volume

Question 9

Contractility

Answer 9

Strength of ventricular contraction
When this increases stroke volume increases

Question 10

Ejection fraction

Answer 10

Normally about 60% of the EDV is ejected

Question 11

Frank-Starling law

Answer 11

Increased EDV results in increased contractility and thus increased stroke volume, this is an intrinsic property of heart muscle

Question 12

How does increased EDV result in increased contractility

Answer 12

The increased EDV stretches the myocardium increasing contraction strength via increased actin and myosin overlap (sarcomere length) + increased sensitivity to Ca2+

Question 13

Sympathetic contractility regulation

Answer 13

Norepinephrine and adrenal epinephrine make more Ca2+ available to sarcomeres increasing contraction strength

Question 14

Extrinsic control contractility

Answer 14

Parasympathetic acetylcholine decreases heart rate which will increase EDV which then increases contraction strength and thus stroke volume but not enough to overcome the slowed heart rate so cardiac output decreases overall

Question 15

Blood flow proportion

Answer 15

Proportional to differences in pressure and inversely proportional to resistance

Question 16

Most important factors in blood flow

Answer 16

Mean arterial pressure and vascular resistance to flow

Question 17

Extrinsic regulation of blood flow

Answer 17

Control by the autonomic nervous system and endocrine system

Question 18

Sympathetic extrinsic control of blood flow

Answer 18

Release norepinephrine onto smooth muscles of arterioles stimulating vasoconstriction increasing cardiac output and total peripheral resistance (alpha)
Release ACh and epinephrine to vasodilator skeletal muscles (beta adrenergic)

Question 20

Parasympathetic extrinsic control of blood flow

Answer 20

Release of ACh leading to vasodilation in limited tissues

Question 21

Myogenic (intrinsic) control of blood flow

Answer 21

Decrease in arterial pressure causes cerebral vessels to dilate to maintain adequate blood flow
High blood pressure causes cerebral vessels to constrict to protect the vessels

Question 22

Metabolic control of blood flow

Answer 22

Decreased oxygens increased CO2, decreased tissue pH, and release k+ promotes vasodilation

Question 23

Circulatory changes during exercise

Answer 23

Sympathoadrenal activity increases and parasympathetic activity decreases causing increased heart rate, stroke volume, and cardiac output
Blood flow to skeletal and cardiac muscles increases

Question 24

Cerebral circulation

Answer 24

Constant at about 750 ml/min, almost exclusively regulated by local intrinsic control or autoregulation
Blood pressure falls cerebral vessels dilate, rises vessels automatically constrict
Hypoventilation (increased CO2) causes dilation, hyper causes constriction

Question 25

Metabolic regulation cerebral flow

Answer 25

Active neurons release chemicals that cause vasodilation so the most active regions of the brain receive increased blood flow (hyperemia)

Question 26

Blood pressure is affected by

Answer 26

Cardiac rate, blood volume/strove volume, and total peripheral resistance

Question 27

Arterial blood pressure is proportional to

Answer 27

Cardiac output x total peripheral resistance

Question 28

Total cross-sectional area

Answer 28

Inversely related to blood pressure Capillaries = large cross- sectional area → low blood pressure

Question 29

Baroreceptors

Answer 29

Low blood pressure → baroreceptors decrease firing rate → increases sympathetic activity → increased cardiac output and total peripheral resistance

Question 30

Ascultatory method

Answer 30

Uses arterial sounds measured by a sphygmomanometer to measure blood pressure

Question 31

Korotkoff sounds

Answer 31

Heard during turbulent flow through an artery, first one is equal to systolic last sound equal to diastolic when laminar flow resumes

Question 32

Pulse pressure

Answer 32

Difference between blood pressure at systole and diastole Reflection of stroke volume

Question 33

Mean arterial pressure

Answer 33

Average pressure in the arteries during the cardiac cycle, difference between this und venous pressure is what drives blood into capillaries Diastolic pressure + 1/3 pulse pressure

Question 34

Hypertension

Answer 34

Systolic above 140 diastolic above 90 Can cause vascular damage including cerebral vessels leading to stroke, ventricular overload leading to arrhythmia or arrest, development of atherosclerosis

Question 35

Treatments for hypertension

Answer 35

Limit salt intake, smoking, drinking, lose weight, exercise K+ supplements, diuretics, B1 blockers to decrease HR, ace inhibitors to block angiotensin II, angiotensin II receptor blockers

Question 36

Circulatory shock

Answer 36

Inadequate blood flow/oxygen utilization by tissues

Question 37

Hypovolemic shock

Answer 37

Low blood volume from injury, dehydration, burns

Question 38

Septic shock

Answer 38

Dangerously low blood pressure due to an infection

Question 39

Congestive heart failure

Answer 39

Cardiac output insufficient to maintain blood flow required by the body

Question 40

Left side failure

Answer 40

Pulmonary edema and shortness of breathe

Question 41

Right-side failure

Answer 41

Systemic edema