Human Circulatory System - St. Dominic High School

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Human Circulatory
System
Transport
Life function by which human
beings absorb and distribute the
materials necessary to maintain
life.
“Closed system” with one muscular
pump
Heart(4 chambers)
Network of blood vessels
Arteries
Carry blood AWAY from the
heart – to body tissues

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Thick walled & elastic
contain cardiac muscle
tissues
these muscles enable the
artery to maintain blood flow
via rhythmic contractions =
pulse
Veins
Carry blood TO the heart – away from body tissues
- thin walled and less elastic
- NO muscle tissues
- muscles surrounding the
veins contract to squeeze
blood through veins
- One way valves – prevent
backflow within the vein
if the veins are defective the
blood flows back and veins
dilate (varicose veins)
Capillaries
Connect arteries to veins

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smallest vessels with thin walls
only one cell thick
diffusion occurs through the walls of capillaries into
cells
branch from the ends of small arteries and carry
oxygenated blood to all tissues in the body
Types of Circulation
1)
Systemic ♥  aorta  to body systems 
veins  ♥
2)
Pulmonary ♥pulmonary artery  lungs 
pulmonary vein ♥
3)
Coronary – supply blood to the heart itself
Lymphatic System
Carry lymph to and from
body tissues
 all cells are suspended in ICF
= intracellular fluid
 contain valves (similar to
veins) to aid in movement
 place where lymph vessels are
enlarged and gathered in
masses = lymph nodes at
specific parts of the body
 contain phagocytic white
blood cells that attack and
destroy bacteria in lymph
The Human Heart

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Size of your fist
Center of the chest – (slightly to the Left)
“pump” made of muscle = myocardium
membrane enclosing it = pericardium
4 Chambers

Atria = Right atrium/Left atrium
(upper)

Ventricles = Right ventricle/Left ventricle
(lower)
Valves

Tricuspid – RA & RV

Mitral – LA & LV

** The heart is a double
pump*
Flow of Blood
Veins  Superior and Inferior Vena Cava  Right
Atrium * Tricuspid valve  Right Ventricle
Lungs (to get oxygen) **via the pulmonary valve to
the pulmonary artery
** In the lungs the blood passes through capillaries, where gas
exchange occurs  by oxygenating blood and removing CO2
from the blood
 blood then returns via the pulmonary vein  Left Atrium
 Left Ventricle  Aorta ** via the aortic valve

http://medtropolis.com/VBody.asp
http://www.edumedia-sciences.com/a387_l2-circulatory-system.html

Right side of the heart
receives O2 deficient
blood and transports it
to the lungs

 picks up O2
* Left side of the heart
receives O2 rich blood
and transports it to the
body
For each heartbeat:
Systolic pressure is peak pressure
in the arteries, which occurs near
the beginning of the cardiac cycle
when the ventricles are contracting.

Diastolic pressure is minimum
pressure in the arteries, which occurs
near the end of the cardiac cycle
when the ventricles are filled with blood.

Heartbeat


contractions = systole
relaxation = diastole
S
120
BP = ---- = ---D
80
(normal BP)
Blood Pressure


Force exerted by circulating blood on the walls
of blood vessels
The pressure of the circulating blood decreases
as blood moves through arteries, arterioles,
capillaries and veins.
Heart valves open and close  heart sounds like
“lub dub”
**Abnormal blood flow through the heart =
murmur
 Pacemaker – triggers heart beat
 EKG (electrocardiogram) – measures voltages
through the heart
  coronary arteries to heart muscle

heart sounds

Heartbeat or pulse is influenced by drugs,
exercise and illness

Ex: high BP, low BP, physical activity, obesity,
ephedrine, drugs

** Exercise increases the heart rate to increase
blood flow to muscles and deliver more O2
Disorders of the Cardiovascular System
Atherosclerosis
Stroke
Heart Attack
Hypertension
Blood



Liquid tissue
55% plasma = clear liquid
 90% water
 10% nutrients, salts, hormones, wastes and
proteins
45% Cells = 3 types
Red blood Cells – RBC
- very numerous
- disc shaped
- no nuclei
- contain hemoglobin – red pigment, carries O2
- live for 120 days – need to be made all the time
- requires Fe (iron) to make hemoglobin
*not enough Fe = Anemia (decreased RBC’s)
* Sickle cell anemia = genetic disease – abnormal
hemoglobin causes cells to sickle
White Blood Cells – protect the body from
disease = defenders
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- fewer in # than rbc’s
- have a nucleus
- larger than rbc’s
- phagocytize bacteria
- made in bone marrow and lymph
* Leukemia – cancer caused by increased production

Platelets – small, noncellular components of
blood
** important to clotting

ICF – Intracellular fluid – rich in salts ICF
drains from tissues within lymphatic vessels,
where it is known as lymph
Blood Groups
ABO classification
Blood Type Antigen
A
A
B
B
AB
A&B
O
None
•
Antibody
Anti-B
Anti-A
none
Anti-A/Anti-B
Rh factor=+ (85%) OR – (15%) is another antigen
Blood Transfusions
Blood Type Donate to
Receive from
A
A & AB
A&O
B
B & AB
B&O
AB (universal recipient)
AB
A,B,O,AB
O (universal donor)
A,B,AB,O
O

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