Transcript I. Overview of the Cardiovascular System

The
Cardiovascular
System
Chapter 12
Human Anatomy &
Physiology
I. Overview of the
Cardiovascular System
The circulatory system can be thought of
as the transport system of the body.
 A closed system consisting of the heart,
blood vessels, and blood

– The heart pumps blood
– Blood vessels allow blood to circulate to all
parts of the body

Function: Deliver oxygen & nutrient-rich
blood to body cells and remove carbon
dioxide and waste
A. Overview of the Heart
The heart is located in the thoracic cavity
between the lungs slightly to the left
 A hollow, cone-shaped muscle about the
size of a fist
 Made up of cardiac muscle

II. Anatomy of the Heart
1. Coverings:
 Pericardium – a double
serous membrane
– Visceral pericardium
(epicardium)
 Next to heart
– Parietal pericardium
 Outside layer

Serous fluid fills the
space between the
layers of pericardium
2. Heart Walls:
 Three layers
a] Epicardium
– Outside layer
– This layer is the visceral pericardium
b] Myocardium
– Middle and thickest layer
– Mostly cardiac muscle
c] Endocardium
– Inner layer
– Made up of simple squamous epithelium
3. Chambers
 The heart has 4
chambers
– Left & right atria –
receive blood
– Left & right ventricles pump blood out
 Chambers are
separated by a septum
4. Heart Valves
 Valves are flaps of connective tissue
between the atria and ventricles
 Moves the blood through the heart in one
direction
 Valves open as blood is pumped through
 Held in place by chordae tendineae
(“heart strings”)
 Valves are closed to prevent backflow

Four valves
a. Atrioventricular valves – between atria
and ventricles, open valves
– left atrium  bicuspid valve  left ventricle
– right atria  tricuspid valve  right ventricle
b. Semilunar valves - between ventricle
and artery, closed valves
– right ventricle  pulmonary semilunar valve 
pulmonary artery
– left ventricle  aortic valve  aorta
5. Major Vessels
 Aorta
– Blood leaves left
ventricle towards body

Pulmonary arteries
– Oxygen-poor blood
leaves right ventricle
towards lung

Vena cava
– Superior and inferior
– Blood from the body
enters the right atrium

Pulmonary veins (4)
– Oxygen-rich blood
from lungs enters left
atrium
IV. Anatomy of Blood Vessels
Blood Vessels are tubes which transport
blood
A. Function:

– Transport blood
– Carry out the exchange of gases and waste
– Regulate blood pressure
– Direct blood flow
B. Types of Blood Vessels
1. Arteries
 Blood vessels
which carry
oxygen-rich blood
away from the
heart to the body.
 The aorta is the
largest artery in
our body
 Thick walls

2. Capillaries
 Microscopic blood vessels which connect
arteries and veins together
 Where exchange of oxygen, carbon
dioxide, nutrients, and waste occur
 One cell layer thick
3. Veins
 Blood vessels which
carry oxygen-poor
blood from the body
back to the heart.
 Thin walls
 Requires muscles to
push blood back to the
heart
C. Diseases
 1. Arteriosclerosis
– The hardening of the arteries due to the
formation of scar tissue
– Leads to hypertension, heart attack, & stroke

2. Varicose veins
– Valves in the veins become weak leading to
abnormal dilations in the superficial veins

3. Phlebitis
– Inflammation of a vein
– Very serious because it can lead to
thromboembolism and death
IV. Circulation of Blood in
the Body
Circulation is the transportation of
blood
A. The goal is to

1. Send oxygen-poor blood to the the
lungs to pick up oxygen and then
2. To pump oxygen-rich blood from the
heart to the body cells
B. Three circulation
pathways
1.
Pulmonary
circulation

2.
Systemic
circulation

3.
From heart to lungs
From heart to body
Coronary
circulation

From heart to heart
muscle
C. Pulmonary Circulation
1.
Flow of blood from the heart to the lungs

DEOXYGENATED BLOOD must have carbon dioxide
removed, so it is sent to the lungs
– Body cells >
1
– Veins >
6
– Vena cava (1)>
3
4
4
– R Atrium (2)>
– Tricuspid valve >
5
2
– R Ventricle >
– Pulmonary Semilunar valve>
– Pulmonary ARTERY (3) >
– Lungs
1
D. Systemic Circulation
1.
Flow of blood from the heart to the body

OXYGENATED BLOOD coming back from the lungs is
pumped to the body cells
– Lungs >
– Pulmonary VEINS (4)>
– L Atrium >
– Bicuspid (mitral) valve >
– L Ventricle (5) >
– Aortic Valve >
– Aorta (6)>
– Arteries >
– Body cells
1
6
3
4
2
1
4
5
Happy Days: Pump your blood

http://www.youtube.com/watch?v=upctP
Ua6RhA
C. Coronary Circulation
1. Flow of blood to the heart tissues

The heart has its own nourishing circulatory system
– Coronary arteries – from aorta to myocardium
(heart muscle)
– Cardiac veins – from the myocardium to the
ventricle

2. Coronary disorders
a. Atherosclerosis – blockage of the
arterial walls due to the build up of
cholesterol that can lead to a heart attack
b. Thromboembolism – blood clot that
breaks away from its origin and is carried
to a new location
 Can lead to a heart attack if embolus blocks a
coronary artery
Comparison of Arteries
3. Prevention & Treatment
a. Aspirin – reduces
stickiness of platelets,
therefore prevents clots
b. Surgery
– i. Balloon Angioplasty – tube
is guided through the blood
vessel to the blockage where
is inflated to open up the
vessel or break the clot
– ii. Coronary Bypass Operation
– a blood vessel from another
part of the body is sutured
from the aorta to the
coronary artery, past the
blocked area
– Allows blood to flow to
cardiac muscle
Videos

Balloon Angioplasty
– http://www.youtube.com/watch?v=F_gVBK6Y
kPA

Coronary Bypass
– http://www.youtube.com/watch?v=8nbscVKK
Sm8
V. Blood
The only fluid tissue in the human body
 Taste, odor, 5x thicker than water
 Color range

– Oxygen-rich blood is scarlet red
– Oxygen-poor blood is dull red
pH must remain between 7.35–7.45
 5-6 Liters or about
6 quarts/body

A. Composition
1. Blood Plasma
 Makes up 55% of blood
 Composed of 90% of water
 Contains nutrients, salts (metal ions),
respiratory gases, hormones, proteins,
waste products
2. Erythrocytes – Red
Blood Cells
 The main function is to
carry oxygen
 Biconcave disks
 Anucleate (no nucleus)
 Outnumber white blood
cells 1000:1
 Each erythrocyte has 250
million hemoglobin
molecules
– Iron-containing protein
– Binds strongly to oxygen
3. Leukocytes – White Blood Cells
 Crucial in the body’s defense against disease
4. Platelets
 Small fragments
produced from
ruptured cells
(megakaryocytes)
 Needed for the clotting
process
B. Blood Disorders


1. Anemia – caused by
low iron or
hemoglobin
– Symptoms: fatigue,
dizziness,
headaches, short of
breath
2. Sickle cell Anemia –
recessive genetic
disorder
– Symptoms: fatigue,
bone pain, ulcers,
delayed growth,
short of breath

3. Hemophilia – recessive
sex-linked bleeding
disorder
– Blood lacks clotting factors
– Minor injuries can cause
uncontrolled bleeding
VI. Physiology of the Heart
A. Conduction System of the Heart
 Initiates, stimulates, and coordinates the
contraction of the atria and ventricles
– Makes the heart an effective pump

2 types of Nodal tissue controls the
heartbeat
– SA (sinoatrial) Node – found in right atrium
 Initiates the heartbeat every 0.85 seconds
 Serves as the pacemaker
– AV (atrioventricular) Node – bottom of right
atrium
The SA node
sends out an
impulse causing
the atria to
contract.
The impulse
reaches the AV
node and
travels along the
AV bundle.
The impulses
travels
throughout the
ventricles to the
Purkinje
fibers.
Ventricles
contract.
B. Cardiac Cycle & Heart Sounds

Cardiac cycle includes all the events that
occur in one heartbeat
– Heart beats ~70x/minute
L & R atria contract simultaneously
 Atria relaxes then L & R ventricles contract
simultaneously
 Systole – contraction
 Diastole - relaxation


1. Atrial systole – 0.15 sec
– Atria is systole (contracted) pumping blood into
ventricles (diastole-relaxed)

2. Ventricle Systole - 0.30 sec
– Ventricle fills with blood and contracts pumping blood
to the aorta and pulmonary arteries

3. Atrial & Ventricle Diastole – 0.40 sec
– Both atria & ventricles are diastole (relaxed) as blood
from the body fills the atria

Bicuspid
Valve
What is that
sound?
- Lup: closing of
the bicuspid and
tricuspid valve
- Dup: closing of
aortic and
pulmonary valve
C. Measuring the Cardiac Cycle

Electrocardiograms (EKG or ECG) are
used to measure the electrical
rhythm of the heart’s contraction
PQRST Waveform
D. Disorders

Damage to AV node = muscles cells in the
ventricles do not beat together results in a
slower heart beat
– Slower heart beat can lead to fibrillation
Fibrillation = lack of blood flow to
the heart
Arrhythmia = irregular heart beat
Tachycardia = more than 100
beats/min
Bradychardia = less than 60
beats/min
Pacemaker

Used to maintain a
consistent heart rate
when the body’s
natural pacemaker
(SA node) is not
properly functioning
C. Vital Signs
1. Pulse
 The stretching
and recoiling of
the arterial wall
as blood surges
through
 Monitored at
“pressure points”
where pulse is
easily palpated
2. Blood Pressure
 A device called a sphygmomanometer
measures the pressure in large arteries
– Systolic: pressure at the peak of ventricular
contraction
– Diastolic: pressure when ventricles relax


Pressure in blood vessels decreases as the
distance away from the heart increases
http://blood-pressure.emedtv.com/high-blood-pressure-video/what-is-bloodpressure-video.html

Measuring blood pressure

Variations in blood pressure
– Normal
 140–110 mm Hg systolic
 80–75 mm Hg diastolic
– Hypotension (Low BP)
 Low systolic (below 110 mm HG)
 Often associated with illness
– Hypertension (High BP)
 High systolic (above 140 mm HG)
 Can be dangerous if it is chronic
 Warning sign for stroke and heart attack risk
Hypertension
Effects of High Blood Pressure

http://www.youtube.com/watch?v=pPxnI
h_WTb8&feature=related

http://blood-pressure.emedtv.com/highblood-pressure-video/what-is-bloodpressure-video.html