The Circulatory System
Function:
• Transports nutrients & wastes
• Contains cells that fight infections
• Helps maintain body temperature by
transporting heat
The Circulatory System
All organisms must be able to transport
nutrients and wastes. Smaller organisms
rely on _________ for this movement; humans
require an organized circulatory system for the
movement of substances
through the body. We have a _______
circulatory system, which means our blood is
______________________. The human circulatory
system includes the heart, the blood vessels, and
the blood.
diffusion
closed
contained in vessels
I. THE HEART (pp. 943-946)
ADD TO NOTES
The heart itself is mostly composed of
________ muscle which forms a thick
layer of tissue known as the ____________.
Humans have a __ chambered heart,
divided by a __________ into right and left
sides to prevent _____________
cardiac
myocardium
4septum
Mixing of blood
A. Structure ADD TO NOTES
1. Chambers
a. Atria (atrium = singular) _______
chambers of the heart that ________
blood.
b. Ventricles - _______ chambers of the
heart that ________ blood.
2. Valves – Flaps of tissue that keep blood
flowing _________________
Upper
receive
lower
pump
in one direction
B. Pathway of Blood Through
the Heart
________→_________→___________→
____________→____→____________→
________→_________→____→_______
ADD TO NOTES
vena cava right atrium right ventricle
pulmonary artery lung pulmonary vein
left atrium left ventricle aorta body
C. Circulatory Pathways
1. Pulmonary Circulation – The blood
entering the right atrium from the body is
____ in oxygen and _____ in carbon
dioxide. The flow of blood from the right
side of the heart to the _____ and back
to the heart is referred to as ___________
circulation.
highlow
lungs
pulmonary
C. Circulatory Pathways
2. Systemic Circulation – The blood
entering the left atrium from the
lungs is _____ in O2 and _____ in CO2. The
flow of blood from the left side of the
heart to the ______ and back to the heart
is referred to as __________ circulation.
high low
body
systemic
D. The Heartbeat
1. Stimulus for Contraction
Although the brain can change the rate &
force of contraction, the heart generates
and maintains its own beat. There is a
small cluster of cardiac muscle cells in the
______________ referred to as the __________.
They trigger an ___________ impulse that
stimulates the contraction of cardiac
muscle cells.
right atrium pacemaker
electrical
Sinoatrial
(SA) node
Atrioventricular
(AV) node
Conducting
fibers
Contraction of Atria Contraction of Ventricles
The Sinoatrial Node
D. The Heartbeat
2. The Pulse
The powerful contraction of the _________
causes a surge of blood to leave through the
_____. This surging action of the blood
continues into the ______ that branch off
from the aorta. Each contraction of the left
ventricle results in another surge of blood in the
arteries leading away from the heart. This surge
can be felt and is known as the _____.
left ventricle
aorta
arteries
pulse
Blood Vessels & Blood
Blood Vessels
Arteries
• carry blood _____from heart
• carry oxygen ____blood
(except for__________)
• Have thick elastic walls
surrounded by _____muscle
• ____is the largest artery in
the body
away
rich
pulmonary
smooth
Aorta
Blood Vessels
Capillaries
– ________ blood vessels
– Walls are only 1 cell thick
– This is where the exchange of ______ &
_____ takes place
smallest
nutrients
waste
Blood VesselsVeins
– Collect blood and carry it _____ to the heart
– Carry oxygen _______ blood (except for _____________ veins)
– Have thinner and less elastic walls
– Have _______to keep blood flowing to heart and not _________
– Contraction of _________ muscles help to move blood toward the heart
– The ____________is the largest vein in the body
back
poor
pulmonary
valves
backwards
skeletal
vena cava
Artery vs. Vein
Vein Valves
Blood Pressure: the force of blood
on the walls of the arteries
– Falls when the heart ______
– Heart is always under pressure
in order to keep blood flowing
through it
– Regulated by autonomic
nervous system
– ________ also regulate blood
pressure by controlling amount
of water in blood- when blood
pressure is high, more water
is__________; this reduces
blood volume
relaxes
Kidneys
removed
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
Blood Pressure
Blood Pressure
– High blood pressure
• forces heart to
___________
• people more likely to
develop heart disease
• obesity is one cause
• controlled by weight
control, exercise, and diet
work harder
Blood– Makes up 8% of body –
____ to___ liters
– Components of blood
• 45% = ____ blood cells,
______ blood cells and
platelets
• 55% = plasma
– mostly ________- 90%
– contains salts, sugars, and
plasma proteins
4 6
red
white
water
What does blood contain?
• 50% Water
• 45% Erythrocytes
• 4% Plasma with
Substances
• 1% Leukocytes +
• Platelets
Blood– Plasma proteins
• Several types of proteins that fight__________, regulate osmotic pressure & help blood ____________
– Red blood cells- erythrocyte- RBC• contain ________________- iron
containing protein that increases ___________ carrying ability of RBC’s
• produced in ______bone marrow
• mature RBC’s have no nucleus so can’t divide
• live about 120 days – when they die they are destroyed & recycled by spleen
infectionclotting
hemoglobin
oxygen
red
Blood– White blood cells – leukocytes- WBC
• fewer in numbers than RBC
• produced in bone marrow
• live for many months or years
• more than 20 different types
• guard against________________, fight_______________, and attack ________________
• an increase in the number of WBC’s is an indication the body is fighting an _____________________
– Platelets• fragments of cells
• when blood vessel is injured, platelets become sticky; they cluster around the wound and release a series of chemicals that start a clotting reaction
• a protein called __________forms a net that traps RBCs and forms a ______
infections pathogensbacteria
infection
fibrinclot
Blood Clotting
Break in Capillary Wall
Blood vessels injured.
Clumping of Platelets
Platelets clump at the site
and release thromboplastin.
Thromboplastin converts
prothrombin into thrombin..
Clot Forms
Thrombin converts
fibrinogen into fibrin, which
causes a clot. The clot
prevents further loss of
blood..
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)
• Heart Attack
– Atherosclerosis in coronary artery
– Heart muscle begins to die
• Symptoms
– Nausea
– Shortness of breath
– Severe chest pain
IMMEDIATE MEDICAL ATTENTION NECESSARY
Disorders Continued
• Anemia
– Caused by either a deficiency of red blood
cells or hemoglobin in RBCs. Less oxygen
available for cells results in a lack of energy
due to decreased ATP production.
Disorders (cont)• Hypertension
– High blood pressure
– Hearts works harder than necessary
– Increases risk of heart attack or stroke
Disorders (cont)• Stroke (ADD TO NOTES)
– 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