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Circulatory System
in Animals
Regents Biology
2008-2009
WHY DO WE NEED A
CIRCULATORY SYSTEM?
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TRANSPORT!
•Unicellular organisms can remove
wastes and absorb nutrients through
their cell __________________
•
They are in direct contact with their
environment
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TRANSPORT!
 Multicellular organisms have layers
and layers of cells which are not in
direct contact with the environment
 Developed a system to transport
nutrients to cells and wastes away
from cells
 The Circulatory System!

What does it mean to circulate??
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 The job of the circulatory system is
to transport nutrients to and remove
wastes from cells
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Human Circulation Includes:
 Blood: liquid transport material with
cells
 Heart: a muscular pump to move the
blood
 Blood vessels: arteries, capillaries
and veins that deliver blood to all
tissues
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The Circulatory System Analogy
 The heart – the engine
 Blood vessels – the roads
 Blood – the bus
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Misconceptions
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THIS IS NOT YOUR HEART.
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THIS IS YOUR HEART.
 About the size of your first.
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While we’re on it…
 Your blood is NEVER blue.
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Brain Pop!
 http://www.brainpop.com/health/bodys
ystems/circulatorysystem/
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Feeding Energy Needs
 Why do we need a
circulatory system?

supplies in
 fuel (sugars)
 digestive system
 oxygen
 respiratory system

waste out
 CO2
 respiratory system

need to pick up & deliver
the supplies & wastes
around the body
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 circulatory
system
Circulatory System
 Organ

heart
 Tissues & cells

blood vessels
 arteries
 veins
 capillaries

blood
 red blood cells
 plasma (liquid)
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Vertebrate Heart
 4-Chambered heart

atria (atrium)
 thin wall
 collection chamber
left
atrium
 receives blood

ventricles
 thick wall pump
right
 pumps blood out atrium
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right
ventricle
left
ventricle
Evolution of circulatory system
Not everyone has a 4-chambered heart
fish
2 chamber
V
amphibian
3 chamber
A
A
A
V
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reptiles
3 chamber
A
V
A
V
birds & mammals
4 chamber
A
V
A
V
Lub-dub, lub-dub
 4 valves in the heart


flaps of tissue
prevent backflow of blood
 Heart sounds


closing of valves
“Lub”
SL
AV
AV
 force blood against
closed AV valves

“Dub”
 force of blood against
semilunar valves
 Heart murmur
leaking valve causes hissing sound
 blood squirts backward through valve
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
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Have a heart?
Ask Questions!!
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2008-2009
Circulatory System
Blood Vessels
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2008-2009
Study Skills - Vessels
 Arteries – A AWAY! Carry
blood away from the heart
 Veins – return blood to the
heart
 CapiLLaries – smaLLest blood
vessels
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Arteries: Built for their job
 Arteries
blood flows away from heart
 thicker walls

 provide strength
for high pressure
pumping of blood

elastic & stretchable
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Coronary artery bypass
bypass surgery
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Veins: Built for their job
 Veins
Blood flows
toward heart
blood returns back to heartOpen valve
 thinner-walled

 blood travels back to heart
at low speed & pressure
 why low pressure?
 far from heart
 blood flows because muscles
contract when we move
Closed valve
 squeeze blood through veins

valves in large veins
 in larger veins one-way valves
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allow blood to flow only toward heart
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 The veins have valves that
prevent back-flow of blood.
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Structure-function relationship
 Capillaries
very thin walls
 allows diffusion of
materials across
capillary

waste
body cell
CO2
 O2, CO2, H2O,
food, waste
O2
food
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Blood Flow
 Blood flows from the heart to


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large arteries which branch
likes trees to smaller and
smaller arteries
At their narrowest vessels are
capillaries where materials can
be exchanged between cells
and the blood
Blood flows from small
capillaries to small veins which
meet up with other small veins
to form large veins
Red Blood Cell in a Capillary
Notice that
one red
blood cell
can barely
fit in a
capillary!
http://upload.wikimedia.org/wikipedia/commons/thumb/2/
2f/A_red_blood_cell_in_a_capillary%2C_pancreatic_tiss
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Circulation of Blood
Circulation
to lungs
 2 part system

Circulation to lungs
lungs
 blood gets O2 from lungs
 drops off CO2 to lungs
 brings O2-rich blood from
lungs to heart

heart
Circulation to body
 pumps O2-rich blood to body
 picks up nutrients from
digestive system
 collects CO2 & cell wastes
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body
Circulation
to body
Stops along the way…
 Lungs

pick up O2 / clean out CO2
 Small Intestines

pick up nutrients from
digested food
 Large Intestines

pick up water from
digested food
 Liver

clean out worn out
blood cells
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More stops along the way…
 Kidneys
filters out cell wastes
(urea)
 extra salts, sugars
& water

 Bone

pick up new red
blood cells
 Spleen

pick up new white
blood cells
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Lymphatic System
 Returns lost fluid back to the
blood
Fluid lost is called lymph
 Lymph nodes (your glands)
filter bacteria and dead cells
out from the lymph
 Cause of “swollen glands”
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Have a heart?
Ask Questions!!
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2008-2009
Circulatory System
Blood
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2008-2009
Blood & blood cells
 Blood is a tissue of fluid & cells

1. plasma
 liquid part of blood
 dissolved salts, sugars, proteins, and more

Cells
 2. red blood cells (RBC)
 transports O2 in hemoglobin
 3. white blood cells (WBC)
 defense & immunity
 4. platelets
 blood clotting
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Blood Composition
 Plasma 55% (mostly water)
 Blood Cells 45%
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Blood Cell Production
ribs, vertebrae,
breastbone & pelvis
 Stem cells
“parent” cells
white blood cells
in bone
marrow
 develop into all
the different
types of blood
red blood
cells

 red blood cells
 white blood cells
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cells
white blood
cells
Red blood cells
 Small round cells
produced in bone marrow
 5 liters of blood in body
 5-6 million RBC in drop of human blood
 last 3-4 months (120 days)

 filtered out by liver
 ~3 million RBC destroyed each second
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Red Blood Cells
 Do NOT have a nucleus
 Can NOT reproduce on their own, they only

come from bone marrow
Hemoglobin

Protein which carries O2
 250,000 hemoglobin proteins in one red blood
cell
O2
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White Blood Cells
 Largest blood cells
 About 8,000 per drop of blood
 Formed in the bone marrow or in the
lymph tissue
 Protect the body against diseases by
forming antibodies (a plan for killing
antigens) or engulfing bacteria

Antigen – foreign invader
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Types of White Blood Cells

1. Phagocytes - engulf bacteria and
viruses by phagocytosis
 (see next slide)

2. Lymphocytes - produce
antibodies which clump bacterial
poisons or bacteria
 antibodies (a plan for killing antigens)
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Remember: Phagocytosis
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emergency repair of circulatory system
Platelets - Blood clotting
chemical
emergency
signals
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platelets
seal the hole
protein fibers
build the clot
STUDY SKILLS
 Red blood cells – Are bowl
shaped and carry Oxygen
 White blood cells –
destroy foreign invaders,
think of a doctors white
lab coat!
 Platelets – form a PLATE
over cuts to stop blood
loss
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Have a heart?
Ask Questions!!
Regents Biology
2008-2009
Cardiovascular disease
 Atherosclerosis & Arteriosclerosis

deposits inside arteries (plaques)
 develop in inner wall of the arteries,
narrowing their channel


increase blood pressure
increase risk of heart attack, stroke, kidney damage
normal artery
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hardening of arteries
Heart Disease
 Heart disease and coronary artery disease are the

leading causes of death in the US.
Causes in most cases are unknown, although
stress, obesity, high salt intake, and smoking can
add to a genetic predisposition.
 No cure--may be treated by medication, exercise &
diet.
 "Silent killer"--millions don't know they have it
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Clogging Artery
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Biology
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http://www2.estrellamountain.edu/faculty/farabee/biob
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Cardiovascular health
 Risk Factors
genetics
 diet

 high animal fat

exercise & lifestyle
 smoking
 lack of exercise
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bypass surgery
Heart Disease
Heart disease death rates 1996-2002
Adults ages 35 and older
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Women & Heart Disease
Death rates for heart disease per 100,000 women, 2002
Risk factors
 Smoking
 Lack of exercise
 High fat diet
 Overweight
 Heart disease is 3rd leading cause of death
among women aged 25–44 years & 2nd
leading cause of death among women aged
45–64 years.
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3.) Stroke – interruption
of blood flow to all or part
of the brain
-- may be caused by
blockage to a blood
vessel or a ruptured blood
vessel
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4.) Leukemia
-- white blood cell cancer
-- many kinds
Some Causes - virus,
radiation,
chemical exposure
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Some symptoms:
frequently sick, higher
than normal total number
of WBC's
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Treatments include:
radiation, chemotherapy,
bone marrow transplants
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