Transcript The Cardiovascular System

The Cardiovascular System
Alabama Course of Study
• Identifying structures and functions of the
Cardiovascular System.
• Tracing the flow of blood through the body.
• Identifying components of blood.
• Describing blood cell formation.
• Distinguishing among human blood groups.
• Describing common Cardiovascular diseases
and disorders:
–
–
–
–
Myocardial Infarction
Mitral Valve Prolapse
Varicose Veins
Arteriosclerosis
Interesting Facts
• The heart pumps 7,000 liters of blood through the body each day,
contracting some 2.5 billion times in an average lifetime.
• It contracts and relaxes some 70 or so times a minute at rest.
• Average adult’s heart size is about 14 centimeters long and 9
centimeters wide.
• Blood vessels strung together end to end could circle the globe 2 ½
times.
• The average 3 year old has 2 pints of blood in their body; the
average adult at least 5 times more.
• A “heartbeat” is really the sound of the valves in the heart closing as
they push blood through its chambers making a “lubb dupp” sound.
Layers of the Heart
• The wall of the heart is composed of 3 distinctive layers- an outer
epicardium, a middle myocardium, and an inner endocardium.
Figure 13.3
• Epicardium- outer layer; protects the heart by reducing friction.
• Myocardium- thick middle layer; consists of cardiac muscle tissue
that pumps blood out of the heart chambers.
• Endocardium- inner layer; consists of epithelium and connective
tissue that contains many elastic and collagenous fibers. Continuous
with the inner linings of blood vessels attached to the heart.
The Pericardium
• The pericardium encloses the heart and
the proximal ends of the large blood
vessels that it attaches to.
• Consists of an outer bag that surrounds a
more delicate, double-layered sac
Parts of the Heart
Structure of the Heart
• Internally, the heart is
divided into four hollow
chambers.
– Upper chambers: atria (have
thin walls and receive blood
returning to the heart)
– Lower chambers: ventricles
(receive blood from the atria
and contract to force blood
out of the heart into the
arteries)
Structure of the Heart cont.
• Septum- partition that
separates the right and left sides
of the heart
• FYI: The Interatrial Septum (which separates the
atria) is only present in the fetal period and is
open during this period. It closes at the time of
birth. The Interventrial Septum (which separates
the ventricles) is supposed to be closed all the
time but sometimes an opening is present at
birth. This would be considered a Congenital
heart disease.
Blood Vessels
• Arteries are strong, elastic
vessels that are adapted
for carrying blood away
from the heart under high
pressure.
– As they divide and become
smaller, they become
arterioles.
• Veins carry blood back to
the atria and follow
pathways that parallel
those of the arteries.
– Microscopic vessels that
continue from capillaries
and merge to form veins
are venules.
Table 13.2
Blood Vessels cont.
• Aorta- largest blood vessel in the
body; receives blood from the
Left Ventricle and carries the
oxygenated blood to every other
part of the body
• Superior Vena Cava- returns
blood back to the Right Atrium
from the upper part of the body.
It is one of the largest veins in
the body.
• Inferior Vena Cava- returns
blood back to the Right Atrium
from the lower part of the body.
Blood Vessels cont.
• Pulmonary
Arteries- carries
blood from the
Right Ventricle to
both of the lungs
where the blood is
oxygenated
• Pulmonary Veinscarries the
oxygenated blood
back to the Left
Atrium in the heart.
Blood Vessels cont.
• Capillaries are the smallest diameter blood
vessels.
• Connect the smallest arterioles and venules
• Have thin semipermeable walls in which
substances in the blood are exchanged for
substances in the tissue fluid surrounding body
cells
Blue: Deoxygenated Blood
Red: Oxygenated Blood
• Pulmonary Circuit- sends oxygen-depleted (deoxygenated)
blood to the lungs to pick up oxygen and unload carbon dioxide.
• Systemic Circuit- sends oxygen-rich (oxygenated) blood and
nutrients to all body cells and removes waste. Figure 13.1
Blood
Interesting Facts
• Men have more blood than women. Men
have 1.5 gallons compared to the 0.875
gallons of women.
• In the US, the most common ABO blood
types are O (47%) and A (41%). Rarer are
type B (9%) and type AB (3%).
Blood Cell Formation
• Also called hematopoiesis
• It begins in the yolk sac, which lies outside the
human embryo.
• Blood cells are manufactured in the liver and
spleen, and still form in bone marrow later in
development.
• Marrow-soft, netlike mass of connective tissue
found within the medullary cavities of long
bones, in the irregular spaces of spongy bone,
and in the larger central canals of compact bone
tissue.
• Two kinds of bone marrow:
– Red marrow
– Yellow marrow
Blood Cell Formation cont.
• Red marrow: red because of oxygen-carrying
pigment, hemoglobin, in the red blood cells;
occupies the cavities of most bones.
– Primarily found in the spongy bone of the skull, ribs,
sternum, clavicles, vertebrae, and hipbones.
• Yellow marrow: stores fat; it is not active in
blood cell production.
– If the body needs more blood, yellow marrow can
become red marrow, which then reverts back to
yellow marrow when there is enough or a surplus of
blood.
Blood Components
• Blood accounts for about 7-8% of our body
weight. Blood transports oxygen and nutrients to
cells and gets rid of carbon dioxide and other
waste products.
• Plays a vital roll in the immune system and in
maintaining a relatively constant body
temperature.
• Blood is a highly specialized tissue composed of
many different components. The 4 most
important ones are red blood cells, white blood
cells, platelets, and plasma.
Blood Components cont.
• Red Blood Cells (erythrocytes)- relatively
large microscopic cells without nuclei that make
up 40-50% of the total blood volume
• RBC transfer oxygen from the lungs to all living
tissues in the body and carry away carbon
dioxide
• RBC are produced in bone marrow from stem
cells at a rate of 2-3 million cells per second.
• Hemoglobin is the gas transporting protein
molecules that make up 95% of a RBC. Each
has about 270,000,000 iron-rich hemoglobin
molecules.
• Anemic people generally have a deficiency in
RBC.
Blood Components cont.
• White Blood Cells (leukocytes)Make up about 1% of blood
volume.
• Most notably occur in the spleen,
liver, and lymph glands.
• WBC’s called lymphocytes are the
1st responders for your immune
system. Granulocytes and
macrophages arrive and destroy
alien cells and get rid of dead or
dying blood cells.
• Individual WBC’s usually only last
18-36 hours before they are
removed, though some live as
much as a year.
Blood Components cont.
• Platelets (thrombocytes)- cells
that clot blood at the site of
wounds
• They do this by adhering to the
walls of blood vessels, thereby
plugging the rupture in the
vascular wall. They also release
coagulating chemicals which
cause clots to form in the blood
that can plug up narrowed blood
vessels.
• They stimulate the immune
system.
• Are about 1/3 the size of RBC’s
and have a lifespan of 9-10 days.
Blood Components cont.
• Plasma- relatively clear liquid protein and salt
solution which carries the RBC’s, WBC’s, and
platelets.
• 55% of your blood’s volume is made up of
plasma and 95% of it consists of water.
• As the heart pumps blood to cells throughout the
body, plasma brings nourishment to them and
removes the waste products of metabolism.
• Plasma also contains blood clotting factors,
sugars, lipids, vitamins, minerals, hormones,
enzymes, antibodies, and other proteins.
Distinguishing Blood Types
• The discovery of blood groups
– In 1901, the Austrian Karl Landsteiner
discovered human blood groups and blood
transfusions became safer
– Mixing blood from 2 individuals can lead to
blood clumping or agglutination. The clumped
red cells can crack and cause toxic reaction.
• What are the different blood groups?
– The differences in human blood are due to the
presence or absence of certain protein
molecules and antigens and antibodies.
…Distinguishing Blood Types cont.
• ABO blood grouping system
– According to the ABO blood typing system, there are
4 different kinds of blood types: A, B, AB, or O (null).
– Blood Group A
• You have A antigens and B antibodies
– Blood Group B
• You have B antigens and A antibodies
– Blood Group AB
• You have both A and B antigens and no A or B
antibodies
– Blood Group O
• You have neither A or B antigens and you have
both A and B antibodies
…Distinguishing Blood Types cont.
• Rh factor blood grouping system
– A person with Rh- blood does not have Rh
antibodies naturally in the blood plasma
– A person with Rh- blood can develop Rh
antibodies in the blood plasma if he or she
receives blood from a person with Rh+ blood,
whose Rh antigens can trigger the production
of Rh antibodies.
– A person with Rh+ blood can receive blood
from a person with Rh- blood without any
problems
BLOOD
GROUP
CAN GIVE
BLOOD TO
CAN RECEIVE
BLOOD FROM
AB
AB
AB, A, B, O
A
A and AB
A and O
B
B and AB
B and O
O
AB, A, B, O
O