Cardiovascular System
SC.912.L.14.36
Describe the factors affecting
blood flow through the
cardiovascular system.
What do I need to know?
 the factors that affect blood flow
through the cardiovascular system:
 blood pressure,
 blood volume,
 resistance,
 disease,
 viscosity, and
 exercise.
 how these factors affect blood flow
The Cardiovascular System
 The human cardiovascular
system is made up of blood
vessels, blood, and the heart
 Together they function to:
 transport materials
 remove waste, and
 distribute waste
The Heart
 The heart is a muscular organ
that pumps blood throughout
the body.
 The heart functions as two
separate pumps.
 In systemic circulation the
left side of the heart pumps
oxygen-rich blood to the rest
of the body.
 In pulmonary circulation
the right side pumps oxygen-poor blood
from the heart to the lungs.
Blood vessels
As blood flows
through the
circulatory
system, it moves
through three
types of blood
vessels:
1. Arteries
2. Capillaries
3. Veins
Resistance
 For blood flowing through a vessel,
resistance is influenced by 4 parameters:
 the radius or thickness of the blood vessel
 the length of the blood vessel
 the viscosity or thickness of the blood
 the presence of an obstruction in a vessel
 If the tube length increases, resistance increases
 If the viscosity increases, resistance increases
 If the tube’s radius increases, resistance decreases
 If there is any obstructions, resistance increases
Show What You Know
The rate at which blood flows through the human body
changes in response to many factors. Which
statement describes one of these factors and its effect
on blood flow?
A. A high viscosity of blood causes an increased
resistance in the blood vessels and leads to slow
blood flow.
B. A low blood pH decreases the rate of diffusion
through the blood vessels and leads to slow
blood flow.
C. The changing of the shape of red blood cells to a
crescent shape decreases resistance and lead to
a faster blood flow.
D. The narrowing of blood vessels increases
pressure and leads to a faster blood
flow.
Show What You Know
Which of the following best describes the
connection between cardiovascular disease and
age?
A. As people age, their blood vessels become
more elastic leading to less cardiovascular
disease.
B. As people age, the heart becomes more
efficient with each pump, increasing cardiac
output.
C. As people age, blood pressure decreases
leading to more cardiovascular disease.
D. As people age, plaque builds up in the
arteries increasing vessel resistance,
which leads to disease.
Show What You Know
After a man suffered a stroke, he was unable to
use his left arm. What happened inside his body
during the stroke that led to his losing the ability
to use his left arm?
A. A blood clot blocked an artery leading into
his left arm during the stroke.
B. Aging capillaries in his left arm collapsed
and shut down during the stroke.
C. A surge of blood into his brain rearranged
some neuron connections during the stroke.
D. Blood flow to a portion of the right side of
his brain was cut off during the stroke.
Show What You Know
A doctor examines a patient who has high blood pressure
and atherosclerosis in the coronary artery. What medical
condition connected to blood flow is most likely to affect
this patient in the future?
A. The patient may develop headaches and confusion
due to cancer in the brain caused by years of low
levels of oxygen supplied to the brain.
B. The patient may develop stiff joints and chest pains
from the high blood pressure applied to the muscle
and joint tissues of the body.
C. The patient may show signs of confusion, weakness,
and partial paralysis due to high blood pressure when
the plaque dislodges and blocks blood flow to the
brain.
D. The patient may suffer a heart attack because of the
reduction in blood flow to the heart muscles due to
severe plaque build-up in the coronary artery.