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CIRCULATORY SYSTEM
CARDIOVASCULAR/CARDIAC
NATURAL AGING CHANGES
Heart muscle weakens: heart pumps
with less force
2. Blood flow decreases (reduced cardiac
output/volume): Older people tire
easily
3. Heart size increases: Heart has to work
harder
4. Blood vessels harden and lose elasticity
with age; they become more narrow with
fatty deposits: diminished blood
flow/higher BP
1.
HEART
Muscle that pumps blood and O2 to cells.
Located L of sternum between 2nd and 5th
ribs.
3 Layers
Endocardium
Myocardium
Pericardium
HEART IS REALLY “2” HEARTS IN
ONE….
LEFT SIDE- PUMPS OXYGENATED
BLOOD TO BODY
RIGHT SIDE – PUMPS UNOXYGENATED
BLOOD TO LUNGS
4 CHAMBERS
Heart Diagram Handout
What separates the sides and the
chambers???
SEPTUM
VALVES
“Gates” that control the flow of blood in 1
direction:
Mitral Valve- LA and LV
Aortic Valve- LV and aorta
Pulmonary Valve- pulmonary artery and RV
Tricuspid Valve- RA and RV
BLOOD VESSELS
Arteries- largest blood vessels that carry
blood AWAY from heart and carry only
oxygenated blood
Veins- Smaller blood vessels that carry
blood TO the heart and carry only
unoxygenated blood.
Capillaries- microscopic blood vessels
that have mixed blood and help exchanges
gases, nutrients and waste products. They
connect arteries and veins.
MAIN VESSELS OF THE HEART
1. Aorta- largest artery, sends blood from
heart to rest of body.
2. Coronary Arteries- arteries that
surround heart and carry O2 to heart
muscle and tissues.
AORTA
MAIN VESSELS OF THE HEART
3.
Superior/Inferior Vena Cavas- 2 large veins that
bring unoxygenated blood from body to R side of
heart
4. Pulmonary Artery- carries unoxygenated blood to
lungs from RV
5. Pulmonary Veins- carries oxygenated blood from
lungs to heart
These are the exceptions to the artery/vein rule in
terms of oxygenated and unoxygenated blood. WHY???
SUPERIOR/INFERIOR VENA
CAVAS
These are the exceptions to the
artery/vein rule…WHY???
4. Pulmonary Artery- carries
unoxygenated blood to lungs from RV
5. Pulmonary Veins- carries oxygenated
blood from lungs to heart
These are the exceptions to the artery/vein
rule in terms of oxygenated and
unoxygenated blood. WHY???
Physiology: How blood flows
through the heart
Pulmonary Circulation
Right sided blood flow: R side of heart
pumps blood to lungs
Pulmonary Circulation
Systemic Circulation
Left sided blood flow: L side of heart
pumps blood to the body systems
Systemic Circulation
How Does the Heart Beat??
Cardiac Cycle:
Mechanical and electrical events that
occur between 1 heart contraction and the
next.
Mechanical- the actual relaxation and
contractions of the heart chambers
Electrical- the conduction system that
involves special neuromuscular tissue that
sends out electrical impulses within the
heart to “tell” the heart cells to contract.
Mechanical Events
1.
2.
3.
Atria relax and fill with blood as
ventricles contract, forcing blood out of
the heart and through the aorta.
Ventricles relax allowing blood to flow
into them.
Cycle repeats itself
Electrical Events/Conduction
System
How Does This Happen?
The rate and rhythm of the cardiac cycle is
controlled by the conduction system. This
system is made up of special neuromuscular
tissue that sends out electrical impulses
that “tell” the heart muscle cells to
contract using a complex set of electrical
events.

Electrical Events/Conduction
System
1.
2.
3.
4.
5.
6.
RA has special area in upper part of
chamber called S-A node. (“Natural
Pacemaker”)
Atria contract
S-A node impulses spread to bottom of RA
to the A-V node
A-V node spreads to septum to the Bundle
of His
Bundle of His spreads to Purkinje Fibers
which reach deep into the ventricle walls.
Ventricles contract
http://highered.mcgr
awhill.com/sites/007249
5855/student_view0/
chapter22/animation
__conducting_syste
m_of_the_heart.htm
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What happen when a person’s
“natural pacemaker” doesn’t work??
EKG (electrocardiogram)
BLOOD
Blood carries nutrients and O2 to cells.
Red Blood Cells (RBC) Formed in bone marrow
and carries O2 Erythrocytes
b. White Blood Cells (WBC) Defends body
against infection Leukocytes
c. Platelets- in charge of blood clotting
Thrombocytes
d. Plasma- liquid portion of blood. Antibodies,
nutrients, gases and waste products.
a.
Functions of Blood
1.
2.
3.
4.
5.
6.
Carries O2 from lungs to cells
Carries CO2 from cells to lungs
Absorbs nutrients
Carries waste products from cells to
kidneys
Helps regulate body temperature
through: constriction/dilation
Maintains fluid balance