Dr. Gebler
Dr. Glenn F. Gebler
Heart
 The heart has 4
chambers
 Right atrium and left
atrium (atria)
 Right and left ventricles
Structure of the Heart
 The heart has four chambers
 The upper chambers are called atria
 right atrium and left atrium
 Atria have thin walls
 They receive blood from the veins
 They send blood to the ventricles
 The lower chambers are called ventricles
 Ventricles are thick walled and muscular
 They pump blood from the heart to the arteries
The Heart is 2 Separate Pumps
Housed in One Organ
 The right and left sides are separated by a wall
(septum)
 The right side of the heart sends blood to the lungs;
pulmonary circuit
 The left side sends blood to the body tissues;
systemic circuit
 Valves keep blood flowing in the forward direction;
valves between the atria and ventricles of each side;
prevent backflow
Valves
 Keep blood flowing in one direction
 Between the atrium and ventricle on
each side
 Atrioventricular (AV) valves
 Tricuspid
 Bicuspid
 Valves between the ventricle and the
artery of each side
 Semilunar valves
Activity 1
 Color mindfully the path that blood takes through the
heart and through the body.
 Pay attention to the pulmonary and systemic circuits
and understand how and where blood is oxygenated.
 Red blood cells pass through the
lungs and pick up oxygen; oxygen
binds to iron atoms in the Hb
molecule
Act. 1 and 2 Blood Pathway Flow
 Follow the blood flow:

Vena cava-R atrium- R Ventricle-pump to the lungs(pulmonary
artery)- coming back (pulmonary vein)- L atrium- -Lventricle- pump to
the body (aorta)- come back to the vena cava
 The valves keep blood flowing one way- a heart murmur is when the
valves fail to close properly and backflow occurs.
 The Septum that divides the 2 halves of the heart keep deoxygenated
blood from mixing with oxygenated blood
 Observe the coronary arteries and veins that feed the heart muscle
Intrinsic System
 Timing of the heart
beat begins with
special pacemaker
called sinoatrial (s-a)
node
SA node
 Atrioventricular node
transmits the stimulus AV node
to contract the
ventricles
AV bundle
 Atria contract
together, then the
Purkinje
fibers
ventricles contract
together
 Lub sound is closing of
the atrioventricular
valves; dup sound is
closing of the
semilunar valves
Heart Model Slides
 The following heart model slides are from an Anatomy
and Physiology Text so there is more detail then you
will be asked to know, just make sure you know the
major blood vessels that we discussed in class.
Blood Vessels: Pipes that Deliver
the Blood
 Arteries carry blood away from the heart
 Arteries have thick, muscular walls
 Arteries carry blood under high pressure from the heart
 A thick layer of smooth muscle tissue allow arteries to
regulate blood flow by changing the blood vessel
diameter


Dilate - enlarge the diameter
Constrict - shrink the diameter
Veins
 Veins carry blood toward the heart
 Blood in veins exerts less pressure than the blood that is
found in arteries
 Blood loses most of its propulsive force after it circulates
through the tissues; blood is only able to return to the
heart because of the action of skeletal muscles
 Lower strength
 Expandable
 Holds large volumes of blood
Blood Pressure Activity 3
 Force exerted by the blood against the arteries and
vessel walls.
 As the heart pumps it pushes blood into the vessels
under pressure
 Systolic pressure
 Ventricular contraction- the force of the heart beat
surging blood into the vessels
 Diastolic pressure
 Ventricles relax between beats.
Activity 3
 As your “blood” flows through the “arteries”, what
happens to flow rate as the diameter decreases?
 It takes longer for your “blood” to flow out of the “heart”.
 To compensate for a decreased diameter vessel what
would your heart do to compensate to maintain the
blood flow rate?
 The heart would have to pump harder and faster to
maintain the same rate of blood flow.
 This creates more strain and stress on the heart.
Blood Pressure
Blood Pressure – What does it
tell us?
 Measured in millimeters of mercury (mm Hg) and
shown as a fraction of
systolic/diastolic
 Normal BP 120/80
 Hypertension – high blood pressure
 Resting systole > 140, diastole > 90
 High BP shows up earlier and is more severe in African
Americans than in other populations- more than half of all
Americans over 65 have HBP
Activity 4: Health Risks
Plaque
 atherosclerosis -Narrowing the vessel diameter and
decreasing amount of blood to flow through and
increases risk of heart attacks
 Deposits
 Cholesterol, LDL, and other fats collect along with
calcium
 cause vessel walls to lose their elasticity. Prevent them
from adjusting as needed.
Atherosclerosis and Hypertension
 Atherosclerosis and hypertension may cause heart attack or stroke –
major underlying cause
 Atherosclerosis
 Artery interior narrows because of lipid deposition and inflammation
 LDLs deposit cholesterol; HDLs remove it
 Fatty Plaques
 Cause inflammation in the artery walls
 Can rupture and spill fatty contents in the the bloodstream


This floating fatty debris can lead to blood clots
Blood clots lead to heart attack and stroke.
 Narrowed blood vessels lead to Hypertension
 Chronically high blood pressure (above 140/90)
Atherosclerotic Plaque
cholesterol
and fat
deposits
narrowed
lumen of
artery
endothelium
lumen of
artery
Cardiovascular Health Risks
 Take your quiz and find out what your risk factors are.
 Write down what you consider to be your greatest risk
factor.
 What can you do to reduce your risk concerning this
risk factor?
 What else can you do right now to improve your heart?