The Circulatory System
You’ve Got to Have Heart
Two Pathways
 Pulmonary
Circulation
–Carries blood to lungs and
back
 Systemic Circulation
–Carries blood to body and
back
Circulatory System Consists of…
 Heart
 Blood
 Blood
Vessels
Heart:
Structure and Function
 Keeps
blood moving
 Large organ
composed of
–cardiac muscle
–rich in mitochondria
–Enclosed by a sac
PERICARDIUM
Structure of Heart (cont)
 Four
chambers
–Two upper (Atria)
Walls thinner
Less muscular
–Two lower (Ventricles)
Walls thicker
More muscular
Do more work
Bloods Path Through the Heart

Both Atria fill at same time
– Rt atrium receives oxygen POOR blood from
body from vena cava
– Left atrium receives oxygen RICH blood from
lungs through four pulmonary veins

After filled with blood atria contract,
pushing blood into ventricle
Both ventricles contract
Right ventricle contracts and pushes
oxygen-poor blood toward lungs,
 against gravity,
 through pulmonary arteries
Bloods Path Through the Heart
(cont)
Left ventricle contracts and forces oxygen
rich blood
 out of heart through
 aorta (largest vessel)
The Pacemaker in the Heart
group
of cells located in the
right atrium
sends out signals that make
the heart muscle contract
regulates the heartbeat
Your Heart: The Vital Pump
At REST, the heart
pumps about 5
QUARTS of blood a
minute.
 During EXTREME
EXERTION (exercise)
it can pump 40 quarts
a minute.

Capillaries of head and arms
Superior vena
cava
Aorta
Pulmonary artery
Pulmonary vein
Capillaries of right
lung
Capillaries of left
lung
Inferior vena cava
Capillaries of abdominal
organs and legs
Circulatory System
BLOOD VESSELS
Your Blood Vessels:
Pathway of Circulation

3 types of vessels
– Arteries
– Capillaries
– Veins
Artery vs. Vein
Arteries:
carries blood Away from heart
– Large, Muscular, and Elastic
– Carries oxygenated blood
– Carried under great
pressure
– Steady, pulsating
–
–
–
–
Capillaries
Smallest vessel
Microscopic
Walls one cell thick
Nutrients and gases diffuse
here (alveoli)
Veins:
Carries blood to heart
– Carries blood that
contains waste and CO2
– Valves to prevent much
gravity pull
Varicose Veins
Damaged Valves in Veins
Time 6:17
Circulatory System
BLOOD
The Blood
 Body
contains 4-6 L
 Consists of
–50% Water
–45% Red Blood Cells
–4% Plasma
– 1% White blood
cells and platelets
Plasma
Platelets
White blood
cells
Red blood
cells
Whole Blood Sample
Sample Placed in Centrifuge
Blood Sample That
Has Been Centrifuged
Plasma
Platelets
White blood
cells
Red blood
cells
Whole Blood Sample
Sample Placed in Centrifuge
Blood Sample That
Has Been Centrifuged
Plasma
Platelets
White blood
cells
Red blood
cells
Whole Blood Sample
Sample Placed in Centrifuge
Blood Sample That
Has Been Centrifuged
Parts of the Blood
Your Blood: Fluid Transport
 A Tissue
Liquid Portion Carries
 Blood cells
–Erythrocytes (RBC - red blood cells)
–Leucocytes (WBC - white blood cells)
 Platelets
 Proteins
–Enzymes
–Hormones – Endocrine System
 Nutrients - Digestive System
 Gases - Respiratory System
Erythrocytes (RBC)

Transporters of
– Oxygen
– Carbon Dioxide

RBC
– Lack a nucleus
– Contain hemoglobin
– Disk-shaped

RBC are produced in red bone
marrow of
–
–
–
–


ribs,
humerus,
femur,
sternum, and other long bones
Lives for 120 days
Old RBC are destroyed in liver
and spleen
Oxygen in the Blood
Hemoglobin, iron
containing molecule
 Loosely picks up
oxygen in the lungs
 Loses oxygen in areas
low in oxygen
(diffuses)

Carbon Dioxide in the Blood
Hemoglobin carries CO2 also
 CO2 is a waste product of
cellular work
 70% of CO2 combines with
water
 The rest travels to the lungs

Leukocytes (WBC)

WBC fight infection
–



Less abundant
Large cells
Some live for
months
–

Attack foreign
substances
Most just a few days
ALL contain nuclei
Platelets
PLATELETS are for CLOTTING blood
 Cell fragments
 Produced in bone marrow
 Short life span (1 week)
 Fibrin (sticky network of protein
fibers)

– Form a web trapping blood cells
Blood Clotting
Break in Capillary Wall
Clumping of Platelets
Clot Forms
Blood vessels injured.
Platelets clump at the site
and release thromboplastin.
Thromboplastin converts
prothrombin into thrombin..
Thrombin converts
fibrinogen into fibrin, which
causes a clot. The clot
prevents further loss of
blood..
The Structures of the Heart
Superior Vena Cava
Large vein that brings oxygen-poor blood from the
upper part of the body to the right atrium
Aorta
Brings oxygen-rich blood from the left
ventricle to the rest of the body
Pulmonary Arteries
Bring oxygen-poor blood
to the lungs
Pulmonary Veins
Bring oxygen-rich blood from each
of the lungs to the left atrium
Left Atrium
Pulmonary Valve
Prevents blood from flowing
back into the right ventricle
after it has entered the
pulmonary artery
Right Atrium
Tricuspid Valve
Prevents blood from flowing
back into the right atrium after it
has entered the right ventricle
Aortic Valve
Prevents blood from flowing
back into the left ventricle
after it has entered the aorta
Mitral Valve
Prevents blood from flowing back
into the left atrium after it has
entered the left ventricle
Left Ventricle
Inferior Vena Cava
Vein that brings oxygen-poor
blood from the lower part of
the body to the right atrium
Septum
Right Ventricle
Control of the Heart
(Nervous System)
Medulla oblongata regulates rate
 Sensory cells stretch when too fast
 Pressure drops when beat is too low

Heartbeat Regulation





Force of blood from left ventricle into arteries
(pulse)
Pacemaker (SA Node), group of cells at top of
right atrium
Electrical impulse, signals BOTH atria to contract
Triggers 2nd set of cells (AV Node)-base of the
right atrium to send message to ventricles, they
contract
EkG – record of electrical changes in the heart
The Sinoatrial Node
Contraction of Atria
Contraction of Ventricles
Sinoatrial
(SA) node
Conducting
fibers
Atrioventricular
(AV) node
Blood Pressure

Blood against the blood vessel’s walls
– The systolic pressure refers to
 the pressure recorded while the ventricles pump
the blood.
– The diastolic pressure refers to
 the pressure recorded as the ventricles fill with
blood.

A normal blood pressure is 120/80
DISORDERS

ATHEROSCLEROSIS
– Fatty deposits called plaque
– Builds up in walls of arteries
– Obstructs flow
– Also a risk if clot breaks free and blocks flow
elsewhere
Disorders (cont)

Hypertension
– High blood pressure
– Hearts works harder than necessary
– Increases risk of heart attack or stroke
Disorders (cont)

Heart Attack
– Atherosclerosis in coronary artery
– Heart muscle begins to die
 Symptoms
– Nausea
– Shortness of breath
– Severe chest pain
IMMEDIATE MEDICAL ATTENTION NECESSARY
Disorders (cont)

Stroke
– Blood clot gets stuck in blood vessels leading
to brain
– Brain cells die due to lack of oxygen
 Or blood vessel burst
– Can lead to paralysis,
 loss of ability to speak
 death
Current PREVENTION
Recommendations





Regular exercise
Weight control
Well balanced diet
Do not smoke
Diet low in saturated
fat
Elaboration

Blood Typing: To Clump or Not to Clump?
Blood Types
Massive loss of blood requires a transfusion
 Four Types

–A
–B
– AB
–O

Inherited from your parents
Blood Types
What happens when you mix blood
types?
 Plasma
contains proteins that
correspond to the shape of the
different antigens
 If you mix one type with the
wrong one, you get CLUMPING
Type O is the universal donor
 Type AB is the universal acceptor

What Makes Our Blood Type?
Blood Transfusions
Blood Type
of Donor
Blood Type of Recipient
A
B
AB
O
A
B
AB
O
Unsuccessful transfusion
Successful transfusion
Rh Factor

Rhesus factor (Rh), also inherited
– Rh+ (have antigen)
– Rh- (NO antigen)

Can cause complications in pregnancies
– mother Rh- 1st baby Rh+ : blood mixes with
mother; mother’s body makes anti-Rh+
antibodies
– 2nd Rh + body attacks baby
– Now have medicine to prevent antibody
formation