1. Heart

2. 1. Generating blood pressure
o Required for blood flow through the
blood vessels
2. Routing blood
o Two pumps, moving blood through the
pulmonary and systematic circulations
3. Regulating blood supply
o Adjusts blood flow by changing the rate
and force of heart contractions as
needed

3.  Pulmonary circulation
o The flow of blood from the
heart through the lungs
back to the heart
o Picks up oxygen and
releases carbon dioxide in
the lungs
 System circulation
o The flow of blood from the
heart through the body
back to the heart
o Delivers oxygen and picks
up carbon dioxide in the
body’s tissues

4.  Heart is located just behind and slightly left
of the breastbone, in ventral thoracic cavity
which is separated from abdominal cavity by
the diaphragm.
 Approximately the size of the fist, weighs
about 10.5oz
 The shape of the heart is like a cone, or an
upside-down pear.

6.  Heart Chambers
o Heart is divided into four chambers: two atria
and two ventricles
 Heart Layers
o The wall of the heart is composed of three layers:
endocardium, myocardium and epicardium
 Heart Valves
o Valves act as restraining gates to control direction
of blood flow : tricuspid, pulmonary, mitral and
aortic valve

7.  There are 2 atria or
upper chambers, and
2 ventricles or lower
chambers
 Chambers are
divided into right
and left sides by
walls called
interatrial septum
and interventricular
septum

8.  Endocardium is the inner layer of the heart lining the
heart chambers. Endocardium lines the inner cavities
of the heart, covers heart valves and is continuous
with the inner lining of the blood vessels.
 Myocardium is muscular middle layer of the wall of
the heart. Myocardium stimulates heart contractions
to pump blood from the ventricles and relaxes the
heart to allow the atria to receive blood.
 Epicardium is outer layer of the wall of the heart.
Provides an outer protective layer for the heart.

9.  Tricuspid valve controls the opening between the right
atrium and the right ventricle. Once the blood enters the
right ventricle it cannot go back up into the atrium again.
 Pulmonary valve prevents blood that has been ejected
into the pulmonary artery from returning to the right
ventricle as it relaxes.
 Mitral valve has two cusps. The blood flows through this
atrioventricular valve to the left ventricle and cannot go
back up into the left atrium.
 Aortic valve is located between the left ventricle and the
aorta. Blood leaves the left ventricle through this valve
and cannot return to the left ventricle.

11.  Blood from the body flows through the right atrium into
the right ventricle and than to the lungs.
 Blood returns from the lungs to the left atrium, enters the
left ventricle, and is pumped back to the body.
This is the video where we can see the blood flow through
the heart:
route of blood flow through the heart

12.  Heart is regulated by autonomic nervous system.
1. Sinoatrical node(pacemaker) – contracts and generates
nerve impulses that travel throughout the heart wall
causing both atria to contract.
2. Atrioventricular bundle – carries impulses down the
septum to the ventricles via the Purkinje fibers.
3. Atrioventricular node – delays cardiac impulses from the
sinoatrial node to allow the atria to contract and empty
their contents first.
4. Purkinje fibers – relays cardiac impulses to the
ventricular cells causing the ventricles to contract.

14. 1. Arteries are the large, thick-walled
vessels that carry the blood away
from the heart.
2. Capillaries are a network of tiny
blood vessels referred to as a
capillary bed. Arterial blood flows
into a capillary bed, and venous
blood flows back out.
3. Veins carry blood back to the heart.
Veins have valves that allow the
blood to move only toward the
heart.
 THERE ARE THREE TYPES OF BLOOD VESSELS:

15.  Myocardial infraction – also known as a heart
attack.
 Myocarditis – inflammation of the muscle layer of
the heart wall.
 Hypertension – blood pressure above the normal
range.
 Coronary artery disease (CAD) – insufficient blood
supply to the heart muscle due to an obstruction
of one or more coronary arteries.
 Thrombus – blood clot forming within a blood
vessel.

16.  arteriole – a small artery
 cardiac – pertaining to the heart
 interventricular – pertaining to between the
ventricles
 interatrial – pertaining to between the atria
 myocardial – pertaining to heart muscle
 valvular – pertaining to a valve
 ventricular – pertaining to a ventricle
 venule – a small vein