Cardiovascular
System
APL2/L3
Cardiovascular System
 Consists
of:
-a muscular pump, heart
-a system of distribution vessels,
arteries, veins and capillaries
-a circulating fluid, blood
Cardiovascular System
 Functions
include:
– transport of oxygen and carbon
dioxide
– delivery of food to cells
removal of waste products from
cells
– distribution of hormones
assists in maintenance of
homeostasis
e.g. temperature regulation
Workings of the heart
 How
much blood is in our body?
 5-6
 What
liters
is average resting HR?
 65-75
bpm
 How
much blood is pumped
throughout the body every day?
 7000
liters
 Throughout
one’s lifetime, heart can
circulates 2.5 billion liters of blood
Blood Vessels
Arteries
 carry


blood away from the heart
relatively thick walls to withstand
higher blood pressure
smooth muscles modify diameter
and thus regulate blood flow
Blood Vessels
Veins
 carry
blood towards the heart
 thinner
walls than arteries, not subject
to high pressure
 contain
one-way valves that regulate
direction of blood flow
Blood Vessels
Capillaries
 connect
arteries to veins
 site
of exchange between blood and
surrounding tissues
 walls
one cell thick
 extremely
numerous, deliver blood
close to all body cells
Coverings of the Heart

Double layered
Pericardium
– Visceral: inner,
delicate lining on
surface of heart
– Parietal: outer, tough
sac fitting loosely
around heart
Pericardial cavity:
space between 2
layers.
 Filled with fluid to ↓
friction

Wall of heart: 3 Layers
Epicardium:
protective outer
membrane
 Myocardium:
middle, heart
wall, rich in blood

– Cardiac muscle

Endocardium:
inner lining of
heart wall
– Purkinje fibers,
collagen, elastin,
BV’s
Human Heart
4
chambers: 2 atria and 2 ventricles
 Atria
receive blood from various
parts of the body, and pump blood
into the ventricles
 Ventricles
pump blood out to various
parts of the body
LUNGS
Double
Loop
System
BODY
Heart chambers: Four

2 Atria: Thin walled
upper chambers
– Receive blood

2 ventricles: Thick
walled lower chambers
– Pump blood out

R. & L. sides
separated by septum
Valves between Atria and
Ventricles
One set
separates the
atria & ventricles
 Tricuspid: (3
cusps)

– Separates Right
atria and R.
ventricle

Bicuspid: (2
cusps)
– Seperates left
atria & L.
ventricle
Valves between ventricles and
blood vessels out of heart



Another set
separates the
exiting blood
vessels and the
ventricles
Pulmonary valve:
Right ventricle &
pulm. Artery
Aortic valve: Left
ventricle & aorta
Right
Semilunar
Valve
Tricuspid
Valve
Blood Flow on Right Side of Heart
Left
Semilunar
Valve
Bicuspid
Valve
Right
Atrium
Right
Ventricle
Blood Flow on Left Side of
Heart
Left
Atrium
Left
Ventricle
Pulmonary
Artery
Vena
Cava
(2 veins)
Aorta
Pulmonary
Veins
(4
veins)
Pulmonary
Artery – O2 poor
blood to lungs
Vena Cava –
O2 poor
blood from
body
Path of Blood Flow in Heart
Aorta – O2
rich blood
to body
Pulmonary
Veins – O2
rich blood
from lungs
Quick Quiz: 10 points

a.
b.
c.
1. What type of blood vessels:
Carry blood low in oxygen back to the heart?
Have higher BP and thick walls, high in oxygen?
Are one cell thick ?
2. Why is the blood flow related to the
heart considered a double-loop system?
3. a. What valve is between the left atria
and left ventricle?
b. What is another name for it?
 4.
What one of the four heart
chambers have the thickest walls?
 Why?
 5.
Blood from the body is received
into the RA via what two large veins?