Transcript Anatomy and Physiology

Anatomy and Physiology
The Cardiovascular System

The cardiovascular system contains the
heart, blood vessels (BVs), and blood.

Its function is to transport oxygen and
nutrients throughout the body. It does
this by circulating blood.

An average body contains ~5 liters of
blood but the heart pumps ~7,000
liters of blood daily while the heart
contracts ~2.5 billion times in an
average lifetime.
The Heart:

This is a powerful
pump

It is found in the
thoracic (chest)
cavity behind the
sternum and
mediastinum
Average heart size
is 14 X 9 cm
It is separated into
chambers: 2 right
and 2 left (or 2
upper and 2 lower)



It is covered by the pericardium (a
membrane) which has 2 layers:
◦ Visceral pericardium (covers the heart;
inner layer); a.k.a. epicardium
◦ Parietal pericardium (covers the visceral
pericardium; outer layer)
◦ The pericardial cavity is the space between
these layers which contains serous fluid
◦ Pericarditis is inflammation of the
pericardium usually caused by viral or
bacterial infection.

This is composed of 3 layers:
◦ Epicardium protects the heart (reduces
friction); this contains connective tissue &
adipose
◦ Myocardium is the middle layer; contains
mostly cardiac tissue
◦ Endocardium is the innermost layer;
contains epithelium & connective tissue
and elastic & collagenous fibers
The Heart Walls
Heart Chambers and Valves:

There are 4 chambers:
◦ The atria (sing. atrium) receive blood
◦ The ventricles send blood (from the atria)

The right & left chambers are
separated by a wall called the septum.

There are several valves in the heart
that provide the main function of
regulating blood flow in ONE direction
only (prevents backflow).
The Heart Walls
and Chambers:
http://www.texasheartinstitute.org/HIC/Topic
s/images/myocard.jpg
◦ Atrioventricular
valves (a.k.a. A-V
valves b/c they are
between the atria
and ventricles): there
is 1 on the right & 1
on the left.
 Tricuspid valve is
between the right
atrium and ventricle;
blood flows from the
right atrium to the right
ventricle.
 Bicuspid valve is
between the left atrium
and ventricle; blood
flows from the left
atrium to the left
ventricle.
Heart Valves:
◦ Pulmonary valve:
at the base of the
pulmonary trunk;
this enables blood
to leave the heart
(and flow to the
lungs thru the
pulmonary
arteries); blood
flows out of the
right ventricle
◦ Aorta valve: at the
base of the aorta
(a large artery);
blood flows out of
the left ventricle
Heart Valves:
http://www.google.com/imgres
Pulmonary Circulation: (heart to lungs)

Pulmonary arteries: carry blood to lungs

Pulmonary veins: return blood from
lungs to heart (left side)
Systemic Circulation: (heart to rest of
body)

Aorta: main artery (largest) that pumps
blood from heart to all body tissues
(except lungs)

Superior & Inferior Vena Cava: bring
blood back into heart from body tissues.
Blood Flow Path: begins
with O2 poor blood:
Right Atrium Right Ventricle
Pulmonary Trunk Pulmonary
Arteries Alveoli of lungs for O2
Pulmonary Veins Left Atrium Left
Ventricle Aortic Valve Aorta
Body
http://www.google.com/imgres

This coordinates the cardiac cycle

Contains the sinoatrial node (a.k.a. S-A node)
located beneath the epicardium:
◦ This acts as the pacemaker of the heart b/c it is
rhythmic (meaning it starts impulses, thereby
generating the heart’s rhythm).

Contains the atrioventricular node (a.k.a. A-V
node) located beneath the endocardium

This acts as the impulse conduction pathway
between the atria and ventricles
The Cardiac Conduction System:
Cardiac Cycle & Sounds:
http://www.google.com/imgres

The cardiac cycle is 1 heart
contraction AND 1 heart relaxation, or
a complete heartbeat.

Atrial systole is atrial contraction while
atrial diastole is atrial relaxation.

When listening to the heartbeat with a
stethoscope, it sounds like lubb-dupp.
The lubb is ventricular contraction
while the dupp is ventricular
relaxation.

A murmur is a sound that is heard when
there is slight damage to a valve of the
heart.
◦ The damage is the leaking of blood through a valve
b/c the valve does not completely close.
http://www.google.com/imgres


An electrocardiogram
(a.k.a. ECG) is a
recording of
electrical charges in
the myocardium
during a cardiac
cycle.
http://www.google.com/imgres
Heart problems can
be detected with the
use of an ECG.
http://www.google.com/imgres
Heart Regulation:
The heart rate can change(temporarily) by certain
factors:
 Neural (ANS) controls: stress
 Hormones & ions: changes or imbalances in
electrolytes (Ca++, Na+, K+), thyroxine, or
epinephrine
 Physical factors: temperature, age, gender
http://www.google.com/imgres
Blood Vessels (BVs):

These include the arteries, arterioles,
capillaries, venules and veins.

The arteries take blood away from the
heart; vasoconstriction & vasodilation
(opening & closing of an artery)
controls blood flow and blood
pressure.
Oxygenated
Blood (red)
http://cache.eb.com/eb/image?id=92806&rendTypeId=34
◦ Tunica intima is the
innermost layer
containing
endothelium (internal
epithelium) which helps
prevent blood clotting
Arteries (& Veins)
have 3 layers:
◦ Tunica media is the
middle layer
◦ Tunica externa is the
outermost layer

The arterioles come
from the arteries
(they are smaller
arteries)
http://www.medicalook.com/systems_images/Veins.jpg

Capillaries are the smallest BVs
◦ Found between arteries and
venules
◦ Gases & nutrients are
exchanged thru their membranes
(semipermeable)
This occurs by diffusion,
filtration & osmosis

The amount of capillaries found within
a tissue varies according to the
tissue’s O2 requirement (more O2
required=more capillaries)
http://biology.bangor.ac.uk/images/bsx1009/fig15-3

Venules are small veins

Veins carry blood to the heart from
the body; these run parallel to
arteries.
◦ Veins have 3 layers (like arteries) but not
as distinct
◦ Thinner walls than arteries
◦ Less elastic but greater diameter than
arteries
◦ Many contain valves which act as flaps
preventing backflow of blood
http://www.brvsa.com/venous.htm
Varicose Veins:
http://www.brvsa.com/images/varicose2.jpg
http://www.brvsa.com/venous.htm
http://www.wakeradiology.com/Portals/0/Varicose1.jpg

Vital Signs:
Arterial pulse,
blood pressure,
rate of respiration,
and body
temperature.

Pulse: each beat of
the left ventricle
as it travels
through the
arterial system.
Physiology of Circulation:

A pulse is felt at
certain points on
the body. This is
due to an artery
close to the
surface of the
skin.

This is the
contraction and
relaxation of an
arterial wall.
http://www.google.com/imgres
Blood Pressure:
http://www.google.com/imgres

Blood pressure can be
defined as the force of blood
against BVs.

When the ventricles
contract with the
maximum pressure is the
systolic pressure.

When the ventricles relax
with the lowest pressure is
the diastolic pressure.
Heart action: this determines
the total volume of blood
entering the arterial system.
 Blood volume: this is ~5
liters or 8% of body weight.
This equals the sum of the
elements and plasma.
 Blood volume is
proportional to bp
(normally). When blood
volume decreases, bp
drops; dehydration will also
influence bp b/c it affects
blood volume.

http://www.google.com/imgres
Factors that Influence Blood Pressure:
Factors that Influence Blood Pressure:
Peripheral Resistance: this is the force of the
friction between blood and blood vessels. This
can hinder blood flow.
 Blood viscosity: this is the ease with which
blood particles move past each other. Greater
viscosity=greater resistance.
 Thicker blood (meaning it has more parts)
creates higher bp.

http://www.google.com/imgres
Additional Factors that may influence blood
pressure:





ANS
Renal Factors (kidneys)
Temperature
Hormones
Diet
Factors that Influence Blood Pressure:
Look up in text or online!
 Know the following:

endocarditis, angina, infarct, ischemia,
fibrillation, tachycardia, bradycardia,
congestive heart failure, pulmonary
edema, varicose veins,
thrombophlebitis, hypotension,
hypertension, atherosclerosis, and
coronary artery disease
THE END!
This slide show was developed by Dana Halloran,
 Cardinal Mooney High School, Sarasota, FL.

Used with her personal permission,
 adapted and amended by Rosa Whiting,
 Manatee School for the Arts, Palmetto, FL.
