Transcript Document

Circulatory System
in Animals
Regents Biology
2006-2007
Feeding the Need
for Energy
 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

circulatory system
Regents Biology
Simpler organisms
When your body is only 2-cell layers thick, you can
get supplies in and waste out just through diffusion

all cells within easy reach of fluid
Regents
Biology
Jellyfish
Hydra
Circulatory system
 Made up of 3 parts

organ
 heart

tissues & cells
 blood
 red blood cells
 blood vessels
(vascular system)
 arteries
 veins
 capillaries
Regents Biology
Circulatory systems
 All animals have:
muscular pump = heart
 tubes = blood vessels
 circulatory fluid = “blood”

open
hemolymph
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closed
blood
Vertebrate Heart
 4-Chambered heart

atria (atrium)
 thin wall
 collection chamber
left
atrium
 receive blood

ventricles
 thick wall pump
right
 pump blood out atrium
Regents Biology
right
ventricle
left
ventricle
Evolution of circulatory system
Not everyone has a 4-chambered heart
fish
2 chamber
amphibian
3 chamber
reptiles
3 chamber
birds & mammals
4 chamber
Birds AND
mammals!
Wassssup?!
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Evolution of circulatory systems
 What advantage was a
4-chambered heart
increase body size
 fuel warm-blooded
 enable flight

 Higher energy needs

greater need for energy,
fuel, O2, waste removal
 warm-blooded animals &
flying need 10x energy
 need to deliver 10x fuel & O2
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convergent
evolution
Heart valves
 4 valves in the heart


flaps of connective tissue
prevent backflow
SL
 Atrioventricular (AV) valve



between atrium & ventricle
keeps blood from flowing back
into atria when ventricles pump
“lub”
 Semilunar valves



between ventricle & arteries
prevent backflow from arteries into
ventricles
“dub”
Regents Biology
AV
AV
Lub-dub, lub-dub
 Heart sounds
closing of valves
 “Lub”

SL
 force blood against
AV
closed AV valves

“Dub”
AV
 force of blood against
semilunar valves
 Heart murmur
leaking valve causes hissing sound
 blood squirts backward through valve

Regents Biology
Cardiac cycle
 1 complete sequence of pumping
heart contracts & pumps
 heart relaxes & chambers fill
 contraction phase

 systole
 ventricles pumps blood out

relaxation phase
 diastole
 atria refill with blood
Regents Biology
Electrical signals
allows atria to empty
completely before
ventricles contract
stimulates ventricles
to contract from
bottom to top, driving
blood into arteries
 heart pumping controlled by electrical impulses
Biology
 Regents
signal
also transmitted to skin = EKG
Cardiac Cycle
ventricles
fill
How is this
reflected in
blood pressure
measurements?
systolic
________
diastolic
chambers fill
pump
(peak pressure)
_________________
fill
(minimum
pressure)
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Biology
110
________
80
ventricles
pump
Measurement of blood pressure
if systolic > 150
hypertension =
or
(high blood pressure)
if diastolic > 90
Regents Biology
Any Questions??
Regents Biology
2006-2007
Circulatory System
Blood Vessels
Regents Biology
2006-2007
Blood vessels
arteries
veins
artery
venules
arterioles
arterioles
capillaries
venules
veins
Regents Biology
Arteries: Built for their job
 Arteries
blood flows away from heart
 thicker walls

 provide strength for high
pressure pumping of blood

elastic & stretchable
 maintains blood
pressure even
when heart relaxes
Regents Biology
Major arteries
aorta carotid = to head
to brain & left arm
to right arm
to body
pulmonary
artery
pulmonary
coronary
artery =
arteries
to lungs
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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
Major Veins
superior
vena cava =
from
upper body
pulmonary
vein =
from lung
inferior
Regentsvena
Biology cava = from lower body
pulmonary
vein =
from lung
Structure-function relationship
 Capillaries
very thin walls
 allows exchange of
materials across
capillary

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Controlling blood flow to tissues
 Capillary function

exchange between blood & tissues
 O2, CO2, H2O, food, waste

blood flow in capillaries controlled by
pre-capillary sphincter valves
Regents
Biology
pre-capillary
sphincters open
pre-capillary sphincters closed
Capillary Beds
 Blood flow

at any given time, only 5-10%
of body’s capillaries have
blood flowing through them
 supply varies as blood is needed
 after a meal, blood supply to
digestive tract increases
 during strenuous exercise, blood
is diverted from digestive tract to
skeletal muscles
Why?

capillaries in brain, heart,
kidneys & liver usually filled
to capacity
Regents Biology
Circulation of Blood
 2 part system

Circulation to lungs
Circulation
to lungs
lungs
 blood gets O2 from lungs
 brings O2-rich blood back
to heart

Circulation to body
heart
 pumps O2-rich blood to
body
 picks up nutrients from
digestive system
 brings CO2 & cell wastes
from body to heart
Regents Biology
body
Circulation
to body
Vertebrate circulatory system
 2 part system
lungs
artery
to lungs
vein from lungs
to heart
heart
vein from body
to heart
body
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artery
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
Regents Biology
More stops along the way…
 Kidneys
filters out wastes
(urea)
 excess salts, sugars
& water

 Bone

picks up new red
blood cells
 Spleen

picks up new white
blood cells
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Any Questions??
Regents Biology
2006-2007
Circulatory System
Blood
Regents Biology
2006-2007
Blood & blood cells
 Blood is a tissue of fluid & cells

plasma (55% of volume)
 fluid
 dissolved salts, sugars, proteins, and more

cells (45% of volume)
 red blood cells (RBC)
 transport O2 in hemoglobin
 white blood cells (WBC)
 defense & immunity
 platelets
 blood clotting
Regents Biology
Blood Cell production
ribs, vertebrae,
breastbone & pelvis
 Stem cells
“parent” cells
in bone
marrow
 differentiate
into many
different types
of cells

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white blood cells
white blood
cells
red blood
cells
Red blood cells
 Small round cells
produced in bone marrow
 lose nuclei & mitochondria

 more space for hemoglobin
 iron-containing protein that transports O2

last 3-4 months (120 days)
 filtered out by liver
 ~3 million RBC destroyed each second
Regents Biology
Hemoglobin
 Protein which carries O2
O2
O2
Regents Biology
Red blood cell production
 5-6 million RBC in tiny drop of human
blood
 5 liters of blood in body = 25 trillion RBC
produce ~3 million RBC every second in
bone marrow to replace cells lost
 each RBC 250,000 molecules
hemoglobin
 each Hb molecule carries 4 O2
 each RBC carries 1 million O2

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emergency repair of circulatory system
Blood clotting
chemical
emergency
signals
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platelets
seal the hole
fibrin protein fibers
build clot
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
Regents Biology
hardening of arteries
Cardiovascular health
 Genetic effects
 Diet

diet rich in animal fat
increases risk of CV
disease
 Exercise & lifestyle

smoking & lack of
exercise increases risk
of CV disease
Regents Biology
bypass surgery
Cardiovascular health (U.S. 2001)
Heart Disease
696,947
Cancer
557,271
Stroke
162,672
Chronic lower respiratory diseases
124,816
Accidents (unintentional injuries)
106,742
Diabetes
73,249
Influenza/Pneumonia
65,681
Alzheimer's disease
58,866
Nephritis, nephrotic syndrome &
nephrosis
40,974
Septicemia
33,865
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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.
Regents Biology
Any Questions??
Regents Biology
2006-2007
Lymphatic system
 Parallel circulatory system

transports WBC
 defending against infection

collects interstitial fluid &
returns to blood
 maintains volume & protein
concentration of blood
 drains into circulatory system
near junction of vena cava &
right atrium

transports fats from digestive
system to circulatory system
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Lymph System
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Thermoregulation
 Vasodilation & vasoconstriction


adjusts blood flow
evaporative cooling
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Biology
Vasoconstriction
Vasodilation
Counter Current Exchange
blood from arteries warms blood in veins
36˚C
core body
temperature
5˚C
temperature
of environment
Warm blood
Veins
Artery
Veins
Cold blood
Capillary
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Biology
Coronary arteries
bypass surgery
Regents Biology