The Cardiovascular System- CVS Physiology
Organ blood flow and blood supply (O2 supply)

Outline the physiological roles of the cardiopulmonary system.
- Supply oxygen to body and remove CO2 and waste, maintain O2 and CO2 homeostasis
- Circulatory system: delivers O2 and aids temp regulation
- Respiratory system: allows exchange O2 and CO2

Explain the concept of demand and supply with respect to body O2 requirement using the Fick Equation.
Examine the processes of O2 delivery and O2 extraction.
Apply the Fick Equation to quantify the rate of tissue metabolism (whole body O2 consumption)
-Demand: oxygen consumption by the body, expressed as volume rate of oxygen per minute
-Supply: cardiac output * arterial-venous oxygen difference
- Cardiac output is given by heart rate * stroke volume
- Fick equation:
VO2 = CO * (a-v) O2 difference
Arterial O2: oxygen determined by gas exchange and gas transport
Venous O2: oxygen that’s left over after cells have extracted what they need from capillaries


What structures within the cardiovascular system promote an increased blood flow to locomotor muscles as
metabolic rate increases?
-the heart pump
-arterioles and veins (vasodilation)
-muscle pump (propels blood towards the heart)
-thoracic pump (refers to breathing in and out)

How do exercising muscles satisfy their increased O2 need?
-Redistribution of blood from visceral region (liver, spleen, pancreas, intestines and kidneys) to muscles
-Increased blood flow through local arteriolar vasodilation

Why are arterioles seen as “resistors”?
The heart develops a pressure difference which moves the blood through the system. Each organ is supplied by
a large artery, smaller arteries, arterioles, capillaries, and veins arranged in series. The total resistance is the sum
of the individual resistances, as expressed by the following equation: Rtotal = Rartery + Rarterioles + Rcapillaries. The
largest proportion (greatest pressure drop) of resistance in this series is contributed by the arterioles.

Explain how arterioles regulate blood flow and volume to regional vascular beds.
-Increase of local metabolites and decrease of oxygen means that the arterioles undergo vasodilation and blood
flow is increased
-Two types of control:
(a) Intrinsic (inside arterioles)
(i) Basal tone
(ii) Local controls- metabolites and active hyperemia (increased blood flow to region)
(b) Extrinsic (outside)
(i) SNA
(ii) Hormonal (can cause vasodilation)
The Cardiovascular System- CVS Physiology
Cardiovascular responses to exercise

Describe how O2 demand is met during physical activity through the following processes: O 2 delivery and O2
extraction (The Fick Equation)
I think that’s bullshit-able, just refer to the previous stuff.


List the normal range of resting VO2, CO, HR, SV, BP and (a-v)O2 difference (tissue oxygen extraction).
VO2
CO
HR
SV
(a-v)O2
L/min or mL/kg/min L/min b/min mL/beat
mL/100mL
Average man
0.25
3.5
6.1
70
87
4.0
World class endurance athlete
0.25
3.5
6.1
45
136
4.0
BP
Describe the cardiovascular responses to submaximal and maximal dynamic exercise:
-Submaximal: Less than one's maximum oxygen uptake, heart rate or anaerobic power
o Cardiac output
- Review the mechanisms that regulate CO.
CO = HR (heart rate) * SV (stroke volume)
HR is regulated by sympathetic and parasympathetic nerves. The sympathetic nerves also affect
stroke volume, which is affected by the Franklin-Starling law and mean arterial pressure.
- Review the Frank-Starling Law of the heart and its relation to cardiac output.
The Frank–Starling law of the heart states that the greater the volume of blood entering the heart during
diastole (end-diastolic volume), the greater the volume of blood ejected during systolic contraction
(stroke volume) and vice-versa.
- Examine the relationship between CO and VO2/Power output.
Increased muscle mass means increases the cardiac output and oxygen consumption
The Cardiovascular System- CVS Physiology
o Heart rate
- Review the mechanisms that regulate HR
- Examine the relationship between HR and VO2/Power output
- List 3 factors that influence the resting HR
o Stroke Volume
- Define end-diastolic and end-systolic volume.
- Review the mechanisms that regulate SV
- Examine the relationship between SV and VO2/Power output.
- Review the concepts of preload and afterload.
o Blood pressure
- What is the physiological meaning of SBP, DBP (what do they tell you about?)
- Review the mechanisms that regulate BP
- Examine the relationship between SV and VO2/Power output.
- Review the relationship between MAP, CO and TPR.
- What factors determine exercise BP?

What are the effects of active muscle mass and exercise intensity on cardiovascular responses during
dynamic exercise?
-Dynamic exercise: upper body vs lower body exercise, e.g. running, cycling, swimming etc
-

Examine the relationship between (a-v)O2 difference and VO2/Power output.





Define the term isometric (static) contraction.
What are the characteristics of this form of exercise?
What is the major cardiovascular response to isometric exercise?
Define the pressor response.
What are the regulatory mechanisms governing blood pressure changes during isometric contractions?
(Examine the muscle chemoreflex).
Explain why isometric work is not recommended in hypertensive patients.
What are the effects of active muscle mass and exercise intensity on cardiovascular responses during isometric
exercise?

