Circulatory System
Label heart diagram for
numbers 1 – 7
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4.
2.
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3.
7.
Circulatory System
Purpose:
– To transport oxygen and food to all cells and
then to retrieve waste products for elimination
Includes:
– The heart, the blood, and the vessels
Ready for Transplant
Photograph by Robert Clark
A human heart destined for
transplant lies cradled in a
TransMedics Organ Care System.
The device can keep a heart warm
and beating—and viable for many
hours longer than the
conventional method for handling
donor hearts: immersion in a
saline solution and packing in ice.
National Geographic Feb. 2007
The Heart

Located in the mediastinal
cavity
– Behind sternum, between the
lungs

Muscular, hollow organ
– Size of a closed fist
The Heart

Comprised of three layers of tissue
– Endocardium- smooth layer of cells that lines
inside of heart
– Myocardium- muscular middle layer (thickest
layer)
– Pericardium- double-layered membrane or
sac, that covers the outside of the heart
The Heart
The Heart


Divided into four chambers
– Upper chambers called
atria
– Lower chambers called
ventricles
Septum- muscular wall that
separates the heart into a
right side and a left side
The Heart
The right atrium receives blood as it
returns from the body cells (this blood has
very little oxygen, is dark red)
 The right ventricle receives blood from the
right atrium and pumps the blood into the
pulmonary artery, which carries the blood
to the lungs for oxygen

The Heart


The left atrium receives oxygenated blood from the
lungs
The left ventricle receives blood from the left atrium and
pumps the blood into the aorta for transport to the body
cells
– The left ventricle works 6 times harder than the right
ventricle because it is responsible for giving the blood
the push it needs to travel throughout the whole body
The Heart

One-way valves keep blood flowing in the
right direction
– Tricuspid valve- between the right atrium and
the right ventricle
– Pulmonary valve- between the right ventricle
and the pulmonary artery
– Mitral valve- between the left atrium and left
ventricle
– Aortic valve- between the left ventricle and
the aorta
The Heart

Although separated by the septum, both
sides work together in a cyclic manner
– Diastole- period of rest
– Systole- period of ventricular contraction
Blood Vessels

When blood leaves the heart, it is carried
throughout the body in blood vessels
Blood Vessels

Three main type of blood vessels:
– Arteries- carry blood away from the heart
 Largest artery is the Aorta
– Capillaries- connect arterioles with venules, the
smallest veins
 The exchange of gases takes place in the capillaries
– Veins- blood vessels that carry blood back to the
heart
 Must overcome gravity to get blood back to the heart
– One-way valves
– Veins are located between skeletal muscles, as muscles
contract, they force the blood forward through the veins
Blood Vessels

To move the blood through the body, a
great deal of force and pressure is
required
– Blood pressure- the force is at its highest
when the ventricles contract, forcing blood
out of the heart and into the arteries. Then
there is a drop in pressure as the ventricles
refill with blood for the next heartbeat
 Measured with a device called sphygmomanometer
Blood
The average adult
contains five liters of
blood (four to six
quarts)
 Blood is comprised of
four components:

–
–
–
–
Plasma
Red blood cells
White blood cells
platelets
Blood
A clear, yellowish fluid called
plasma makes up the rest of
blood. Plasma, 95 percent of
which is water, also contains
nutrients such as glucose, fats,
proteins, and the amino acids
needed for protein synthesis,
vitamins, and minerals. The level
of salt in plasma is about equal to
that of sea water. The test tube
on the right has been centrifuged
to separate plasma and packed
cells by density.
Blood

Red blood cells
– Very small and numerous
– Average body has more
than 25 trillion red blood
cells at any given time
– Live for about 3 – 4
months then die
– New red cells are created
at the rate of 2 million
every second
– Contain hemoglobin- a
protein that attracts
oxygen molecules
White blood cells
Body’s main defense
against germs
 Normal count is 5,000
to 10,000 leukocytes
per cubic millimeter of
blood
 Usually live around
three to nine days
 Different types of
leukocytes

Platelets
Smaller than red
blood cells
 Help blood to clot
when there is a cut
 Also called

thrombocytes
Normal count is
250,000 to 400,000
per cubic millimeter of
blood
 Usually live 5-9 days

Diseases and Abnormal Conditions
Anemia- inadequate
number of red
blood cells,
hemoglobin, or both
 Aneurysm –
ballooning out of, or
saclike formation
on, an artery wall

Diseases and Abnormal Conditions
Arteriosclerosis- hardening or thickening
of the arterial walls
 Atherosclerosis- fatty plaques (frequently
cholesterol) are deposited on the walls of
arteries

Diseases and Abnormal Conditions
Congestive heart failure (CHF)- condition
that occurs when the heart muscles do not
beat adequately to supply the blood needs
of the body
 Embolus- foreign substance circulating the
bloodstream

– Air, blood clot, bacterial clumps, a fat globule
Diseases and Abnormal Conditions
Hemophilia- inherited disease, blood is
unable to clot
 Hypertension – high blood pressure
 Leukemia- malignant disease of the bone
marrow, results in a high number of
immature white blood cells

Diseases and Abnormal Conditions
Myocardial infarction- heart attack, occurs
when a blockage in the coronary arteries
cuts off the supply of blood to the heart,
the tissue dies and is known as an infarct
 Phlebitis- inflammation of a vein
 Varicose veins- dilated, swollen veins that
have lost elasticity and cause decreased
blood flow

Dr William Harvey
Dr. Dwight Harken
Dr Charles Bailey
Dr. Wilfred ('Bill') Bigelow
Dr. Walton Lillehei
Lillehei in 1998. He's with
Jacquelin Weeks, who
underwent the first open heart
surgery in 1952, when she was
five years old. (Photo courtesy
of the University of Minnesota)
Dr. John Gibbon
Dr. Dennis Melrose
Dr. Christiaan Barnard
Dr. Norman Shumway
Dr. Randas Batista
Label heart diagram for numbers 1 – 12
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