THE CIRCULATORY SYSTEM
• Kelly Eom
• Vivian Seo
• Jessie Quan
Circulatory system
• Diffusion is inefficient over long distances.
• Circulatory system rapidly transport fluid
throughout the body.
• Main functions
- exchange gases
- absorb nutrients
- dispose of wastes
Circulatory system
• Open circulatory system:
-It pumps blood into an internal cavity
called sinuses, which bathe tissues with an
oxygen- and nutrient-carrying fluid called
hemolymph.
-The hemolymph returns to the pumping
mechanism of the system, a heart, through
holes called ostia.
-It occurs in insects and most mollusks.
Circulatory system
• Closed circulatory system:
-The nutrient-, oxygen-, and waste-carrying
fluid, blood, is confined to vessels.
-It is found among earthworms, mollusks,
and vertebrates.
- Humans and other vetebrates have a
closed circulatory system specifically called,
cardiovascular system.
Cardiovascular system
• Arteries- vessels moving
away from the heart/
oxygenated blood
• Arterioles- branched
smaller vessels of arteries
• Capillaries- smallest
vessels/ gas and nutrient
exchange
• Capillary beds- networks of
capillary vessels
• Venules-vessels returning
to the heart/ deoxygenated
blood
• Veins- larger vessels of
venules
Please put this slide in slide show.
Blood flow
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1. Oxygen-poor blood from the body flows
into the right atrium (on the right side of
heart) through two veins, the upper
superior(anterior) vena cava and the lower
inferior(posterior) vena cava.
2. The blood moves through the right
atrioventricular valve(AV valve) and flows
into the right ventricle.
3. Right ventricle pumps blood to the lungs
via the pulmonary arteries.
4. As blood flows through capillary beds in
the left and right lungs, it releases waste
gases and picks up oxygen.
5. This newly oxygen-rich blood returns
from the lungs to the left atrium through
the pulmonary veins.
6. The blood flows through the left atrium
into the left ventricle as ventricle opens and
the atrium contracts.
Blood Flow
• 7. The left ventricle pumps the
oxygen-rich blood out through the
aorta, which conveys blood to
arteries leading throughout the
body.
• 8. Branches from aorta lead to
capillary beds in the head and
arms.
• 9. The aorta continues to posterior
direction, in abdominal organs
and legs.
• 10. Oxygen-poor blood from the
head, neck, and forelimbs is
channeled into superior vena cava.
• 11. Blood from the trunk and hind
limbs is drained by the inferior
vena cava.
• 12. The blood goes into the right
atrium.
Heart
• About the size of a
clenched fist
• Consists mostly of cardiac
muscle
• Two atria: have thin walls
and serve as collection
chamber for blood
returning to the heart
• Ventricles: have thicker
walls and contract more
strongly than the atria
- left ventricle: must
pump blood to all body
organs→ strong
contraction
Heart
• The systemetic circuit: the circulation
pathway throughout the body
• The pulmonary circuit: the blood pathway
between the right side of the heart, to the
lungs, and back to the left side of the heart
The cardiac cycle
• The cardiac cycle: one complete sequence of pumping and
filling
- Systole: the contraction phase
- Diastole: the relaxation phase
• The cardiac cycle is regulated by
→ autorhythmic cells : specialized tissues in the heart
: self-excitable and able to initiate contractions without
external stimulation by nerve cells.
• Cardiac output- the volume of blood per minute that the left
ventricle pumps into the systemic circuit
- depends on : 1. heart rate- the rate of contraction
2. stroke volume- the amount of blood
pumped by the left ventricle in each
contraction.
The cardiac cycle
• Four valves in heart
-Consist of flaps made of connective tissue
-Prevent backflow
-Keep blood moving in the correct dirrection
• Atrioventricular(AV) valves: between each
atrium and ventricle
- Anchored by strong fibers that prevent
them from turning inside out
- Pressure generated by the ventricles closes
AV valves
• Semilunar valves: where the aorta leaves the
left ventricle/ the pulmonary artery leaves the
right ventricle
- Forced open by pressure generated by
contraction of ventricles
• Pulse: the rhythmic stretching of arteries
caused by the pressure of blood driven by the
powerful contractions of the ventricles
• Heart murmur
- result of defect in one or more valves
- Detectable as a hissing sound when a
stream of blood squirts backward through a
valve
Heart beat
• The cardiac cycle occurs as
1.The SA(sinoatrial) node, or
pacemaker, located in the upper
wall of the right atrium,
initiates the cycle
-by simultaneously
contracting both atria
-by sending a delayed
impulse that stimulates the
AV(astrioventricular) node.
Heart beat
2. The AV node in the lower
wall of the right atrium
sends an impulse through
the bundle of His, nodal
tissue that passes down
between both ventricles and
then branches into the
ventricles through the
Purkinje fibers.
- This impulse results in
the contraction of the
ventricles.
Heart beat
• 3. →When the ventricles
contract(the systole phase)
- blood is forced through the
pulmonary arteries and aorta.
- the AV valves are forced to close
as well.
→ When the ventricles relax(the
diastole phase)
- backflow into the ventricles
causes the semilunar valves to close.
- The closing of AV valves, followed
by the closing of the semilunar
valves, produces the characteristic
“lub-dup” sounds of the heart.
Blood
Blood
• Volume of flow per second must be constant
through the entire pipe.
• Blood is constantly flowing through out bodies.
Volume of flow per second must be
constant through the entire pipe.
• Since volume of flow per second must be
constant through entire pipe, fluid must flow
faster as cross-sectional are of pipe narrows.
• The total cross-sectional are of capillaries
determines flow rate.
• Blood travels over a thousand times faster in
aorta.
• Velocity change follows from the law of
continuity, which describes fluid movement
through pipes.
• A fluid flows through narrower segments of
the pipe faster than it flows through wider
segments.
Blood is constantly flowing through out
bodies
• Blood is pumped by the heart.
• Blood travels through blood vessels.
• Blood Carries nutrients, water, oxygen, and
waste products.
• Red blood cells, white blood cells, platelets,
and plasma are in the blood.
Blood is pumped by the heart.
• Heartbeat gives pressure to blood.
• Blood pressure is the main force driving blood
from the heart to the capillaries.
• Blood pressure, the hydrostatic force exerted
against wall of blood vessel.
• Blood pressure is highest in the arteries during
systole which is called systolic pressure.
• Blood flow velocity decreases markedly in
arterioles and is lowest in capillaries.
• Hydrostatic pressure drives blood from heart
to capillary beds.
• Peripheral resistance which is caused by narrow
openings of arterioles impeding the exit of blood
from arteries causes swelling of arteries during
systole.
• Recoiling of stretched elastic arteries during
diastole creates diastolic pressure.
• Diastolic pressure maintains continuous blood
flow into arterioles and capillaries.
Blood travels through blood vessels.
• Blood leaves the heart from left ventricle to the
aorta which is the largest artery in the body.
• Blood that leaves the aorta has a lot of oxygen
which is important for cells to do their function.
• Oxygen rich blood travels throughout arteries
into smallest arterioles.
• Blood travels through capillaries to vein to go
back to the heart.
• When blood reaches lungs, carbon dioxide is
removed from blood and replaced with fresh
oxygen that had inhaled through lungs.
• Blood flows through vessels of circulatory
system at uneven speeds and pressures.
Arteries
• Arteries have three layers.
• On outside, a layer of connective tissue with
elastic fibers allows vessel to stretch and recoil.
• Middle-layer contains smooth muscle and more
elastic fibers.
• Lining the lumen of all blood vessels, an
endothelium, is a single layer of flattened cells
that provides a smooth surface that minimizes
resistance to flow of blood.
• Blood vessels that carry oxygen rich blood.
• Arteries transport blood away from heart.
• Arteries carry bright red blood which color
comes from oxygen that it carries.
• Arteries have thicker middle and outer layers
than veins.
• Thicker walls of arteries provide strength to
accommodate blood pumped rapidly and at high
pressure by heart.
• Thinnest arteries are called arterioles.
Capillaries
• Capillaries are tiny and thin blood vessels.
• capillaries connect arteries to veins.
• Nutrients, oxygen, and wastes pass in and out
of blood through capillary walls.
• Capillaries’ thin walls consist only of
endothelium and its basement membrane.
• Total cross-sectional area is much greater in
capillary beds than in any other part of
circulatory system.
• Capillaries are only vessels with walls thin
enough to permit the transfer of substances
between the blood and interstitial fluid.
• The slower flow of blood through tiny vessels
enhances exchange.
• When blood leaves the capillaries and enters
venules and veins, it speeds up reduction in
total cross-sectional area.
• During strenuous exercise, blood is diverted
from digestive tract and supplied more
generously to skeletal muscles and skin.
• Two mechanisms regulate distribution of blood
in capillary beds.
• Both depend on smooth muscles controlled by
nerve signals and hormones.
• In one mechanism, contraction of smooth
muscle layer in wall of an arteriole constricts
vessel, reducing its diameter and decreasing
blood flow through it to a capillary bed.
• In other mechanism, rings of smooth muscle
called precapillary sphincters which are
located at entrance to capillary beds control
flow of blood between arterioles and venules.
• Exchange of substances between blood and
interstitial fluid that bathes cells takes place
across thin endothelial walls of the capillaries.
• Small molecules, like oxygen and carbon
dioxide, diffuse down concentration gradients
across endothelial cells.
• Diffusion can occur through clefts between
adjoining cells.
• Blood pressure within capillary pushes fluid
through capillary clefts.
• Blood cells suspended in blood and most proteins
dissolved in blood are too large to pass readily
through endothelium and remain in capillaries.
• Blood proteins remaining in capillaries create
constant osmotic pressure from arteriole to
venule end of a capillary bed.
• Difference between blood pressure and osmotic
pressure drives fluids out of capillaries at the
arteriole end and into capillaries at the venule
end.
• Lost fluid and proteins return to blood via the
lymphatic system.
• The fluid called lymph is in lymphatic system; its
composition is about same as interstitial fluid.
• Lymph vessels have valves that prevent backflow
of fluid toward capillaries.
• Along a lymph vessel are organs called lymph
nodes.
• When body is fighting an infection, lymph nodes
become swollen and tender.
• Lymphatic system helps defend against infection
and maintains volume and protein concentration
of blood.
Vein
• Arteries have three layers.
• On outside, a layer of connective tissue with
elastic fibers allows vessel to stretch and recoil.
• Middle-layer contains smooth muscle and more
elastic fibers.
• Lining the lumen of all blood vessels, an
endothelium, is a single layer of flattened cells
that provides a smooth surface that minimizes
resistance to flow of blood.
• Veins carry oxygen poor blood back to heart.
• Smallest veins, venules, join larger veins that
open into heart.
• Thinner-walled veins convey blood back to the
heart at low velocity and pressure.
• Blood in the vein flows mainly by muscle
actions.
• Skeletal muscles squeeze veins and push blood
through them.
• Flaps of tissue within veins act as one-way
valves that allow blood to flow only toward the
heart.
Blood Carries nutrients, water, oxygen,
and waste products.
• Nutrients, water, oxygen, and waste products
are carried by blood cells in blood vessel to
transport to and from body cells.
Red blood cells, white blood cells,
platelets, and plasma are in blood
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Red blood cells
White blood cells
Platelets
Plasma
Red blood cell
• Red blood cells carries oxygen and carbon
dioxide.
• Red blood cells pick up oxygen in lungs and
transport it to all body cells.
• Red blood cells gather up carbon dioxide
after delivering oxygen to cells.
• Red blood cells transport carbon dioxide
back to lungs where it is removed from body
when human exhales.
• About 5,000,000 red blood cells are in one
drop of blood.
• Red blood cells are heavier than other blood
cells.
• Red blood cells are made in bone marrow
which is a soft tissue inside of bone.
• Red blood cells are also called erythrocytes.
• The small size and biconcave shape of
erythrocytes provide a large collective surface
area for the total population of erythrocytes.
• The greater of total area of erythrocyte
membrane in a volume of blood leads to more
rapid oxygen diffusion.
• Hemoglobin are iron-containing protein that
transports oxygen.
• Erythrocytes lack nuclei and mitochondria and
generate AP exclusively by anaerobic
metabolism.
White blood cells
• White blood cells are also called leukocytes.
• White blood cells help body fight off germs.
• White blood cells attack and destroy germs
when they enter the body.
• Body produces more white blood cells if
infection exists in the body.
• White blood cells produce in bone marrow.
• Blood contains five major types of white blood
cells which are monocytes, neutrophils,
basophils, eosinophils, and lymphocytes.
• Monocytes and neutrophils are phagocytes
which engulf and digest bacteria and debris
from body’s own dead cells.
• Lymphocytes develop into specialized B cells
and T cells which produce immune response
against foreign substances.
• White blood cells spend most of time outside
the circulatory system, patrolling through
interstitial fluid and lymphatic system, where
most of battles against pathogens are waged.
Platelets
• Platelets are blood cells that help stop
bleeding.
• As platelets stick to opening of damaged
vessel they attract more platelets, fibers, and
other blood cells to help form a plug to seal
broken blood vessel.
• The wound stops bleeding when platelet plug is
completely formed; the platelet pugs are called
scabs.
• Platelets produce in bone marrow.
• Platelets have no nuclei and originate as
pinched-off cytoplasmic fragments of large
cells in bone marrow.
Stem cells
• Erythrocytes, leukocytes, and platelets all
develop from a common source.
• A single population of cells called pluripotent
stem cells in red marrow of bones, particularly
ribs, vertebrae, breastbone, and pelvis.
• A negative- feedback mechanism, sensitive to amount of
oxygen reaching body’s tissues via blood, controls
erythrocyte production.
• If tissues do not receive enough oxygen, kidney synthesizes
and secretes a hormone called erythropoietin which
stimulates production of erythrocytes.
• If blood transport excessive oxygen, level of EPO falls and
erythrocyte production slows.
Plasma
• Plasma is the liquid part of the blood.
• Approximately half of blood is made of
plasma.
• The plasma carries blood cells and other
components throughout body.
• Plasma is made in liver.
• Plasma is lighter than other blood cells.
• Plasma is 95% of water and other 5% of
dissolved substances including salts.
Cardiovascular
Disease
Cardiovascular Disease
The Cardiovascular diseases are
disorders of the heart and blood vessels. The
tendency to develop cardiovascular disease is
inherited to some extent, but lifestyle also plays
a important role. smoking, lack of exercise, a
diet rich in animal fat, and high levels of
cholesterol in the blood are the nongenetic
factors that increase the risk of cardiovascular
problems.
<Cardiovascular Disease>
LDLs and HDLs
- One measure of an individual’s
cardiovascular health or risk of
arterial plaques can be gauged by the
ratio of low-density lipoproteins
(LDLs) to high-density lipoproteins
(HDLs) in the blood.
-LDLs is often called as the “bad
cholesterol” and is associated with
the deposition of cholesterol in
arterial plaques, growth that develop
on the inner walls of arteries.
-HDLs (“good cholesterol). may
reduce cholesterol deposition
<Cardiovascular Disease>
Atherosclerosis
Deposition of cholesterol thickens and
roughens this smooth lining.
Atherosclerosis is a disease in which
plaque builds up inside your arteries. At
plaque sites, the smooth muscle layer of
an
artery thickens abnormally and becomes
infiltrated with fibrous connective tissue
and lipids such as cholesterol. The rough
lining of an atherosclerotic artery
encourages the adhesion of platelets,
triggering the clotting process, and
interfering with circulation
<Cardiovascular Disease>
HEART ATTACK AND STROKE
- A heart attack occurs when blood flow to a section of heart
muscle becomes blocked. If the flow of blood isn’t restored
quickly, the section of heart muscle becomes damaged
from lack of oxygen and begins to die.
- A stroke is the death of nervous tissue in the brain.
- Both heart attack and stroke are the final blow from
unaware of their disease (ex. Atherosclerosis) until
catastrophe strrikes.
- These diseases frequently result from a thrombus that
clogs a coronary artery or an artery in the brain.
HOW DOES THE CIRCULATORY
SYSTEM INTERACT WITH OTHER
SYSTEMS?
HOW DOES THE CIRCULATORY SYSTEM
INTERACT WITH OTHER SYSTEMS?
• The cardiovascular system delivers oxygen,
hormones, nutrients and white blood cells
around the body by pumping blood, and it
removes waste products. By interacting with
other systems, it maintains homeostasis (The
steady state physiological conditions for body.)
HOW DOES THE CIRCULATORY SYSTEM
INTERACT WITH OTHER SYSTEMS?
• With Respiratory System..
The major function of the respiratory system is gas exchange between the
external environment and an organism's circulatory system. Gas exchange
facilitates blood oxygenation with removal of carbon dioxide and wastes
from the circulation. Alveolus are multilobed air sacs that constitute the
gas exchange surface of the lungs. The epithelial cells in these walls are
close to the pulmonary capillaries which are composed of a single layer of
endothelial cells. Their location allows permeability of gases, hence, and
gas exchange.
HOW DOES THE CIRCULATORY SYSTEM
INTERACT WITH OTHER SYSTEMS?
• With Endocrine System..
The hormones are produced by the endocrine system. The
hormones are transported through the blood from the
circulatory system and they carry the information and
instructions from one set of the cells to another. For example,
one of the hormones produced by the heart helps control the
kidneys' release of salt from the body.
HOW DOES THE CIRCULATORY SYSTEM
INTERACT WITH OTHER SYSTEMS?
• With Reproduction System..
The circulatory system also transport gases, nutrients, wastes,
and hormones for reproduction. It supplies the nutrients for
making sperms in male and eggs in female. During the
pregnancy, The placenta (the structure in the pregnant uterus
for viviparous fetus) grows tightly fused to the wall of the
uterus. Its blood vessels, supplied by the fetal heart, are
literally bathed in the mother's blood. Although there is
normally no mixing of the two blood supplies, the placenta
does facilitate the transfer of a variety of materials between the
fetus and the mother.
HOW DOES THE CIRCULATORY SYSTEM
INTERACT WITH OTHER SYSTEMS?
• With Nervous System..
The nervous system definitely needs nutrients to be brought to
it and waste molecules to be taken away, which is
accomplished by the circulatory system. The nervous system
also affect the circulatory system. The signals from various
parts of the nervous system change the heart rate, either faster
or slower, change the constriction or dilation of the blood
vessels, which alters the rate of flow for the circulatory
system. It also uses the circulatory system to dissipate heat if
the body and the brain senses that it is too warm.
HOW DOES THE CIRCULATORY SYSTEM
INTERACT WITH OTHER SYSTEMS?
With Excretion System..
Malpighian tubules are excretory organs that operate in
association with the open circulatory system of grasshoppers
and other insects. Blood in the open sinuses of the grasshop
pers' body surrounds the Malpighian tubules. The ends of the
tubules absorb fluid from the blood. As the fluid moves
through the tubules, uric acid is precipitated. A lot of the water
and other salts are reabsorbed into the grasshopper's blood.
The remaining fluid plus uric acid passes out of the
Malpighian tubule and enters the gut. Water is reabsorbed from
the digestive tract. Finally, the uric acid is eliminated from the
rectum as a dry mass
HOW DOES THE CIRCULATORY SYSTEM
INTERACT WITH OTHER SYSTEMS?
With Immune System (lymphatic system)..
Wastes and excess interstitial fluids enter the circulatory
system when they diffuse into capillaries. However, some of
them are returned to the circulatory system by way of the
lymphatic system, a second network of capillaries and veins.
The fluid in these lymphatic veins, called lymph, moves
slowly through lymphatic vessels by the contraction of
adjacent muscles. Valves in the lymphatic veins prevent
backflow. Lymph returns to the blood circulatory system
through two ducts located in the shoulder region. In addition to
returning fluids to the circulatory system, the lymphatic system
functions as a filter.
HOW DOES THE CIRCULATORY SYSTEM
INTERACT WITH OTHER SYSTEMS?
With Skeletal System..
The bone marrow inside the bone produces red blood
cells and white blood cells (making blood). After
making the blood, the bone marrow sends its new
blood to the circulatory system. Then the circulatory
system sends it to the heart and the cycle continues.
Heart Activity
Write corresponding structure name.
1.
9.
2.
10.
3.
11.
14
4.
12.
15
5.
13.
16
6.
14.
7.
15.
8.
16.
11
12
1
13
2
3
4
5
6
7
8
9
10
Blood Activity
Number 1
Number 2
Hydrostatic
pressure
What kind
of pressures cause
each movement to
Osmotic
different direction?
pressure
1. Carbon
dioxide
2. Oxygen
What is number 1 and 2?
<Cardiovascular Disease>
ACTIVITY
HINT!!
1) It is also known as “good
cholesterol” and it may reduce
cholesterol deposition.
1
▶ HDLs (High density lipoprotein)
1
2
2) It is known as “bad cholesterol”
and is associated with the
deposition of cholesterol in
arterial plaques, growth that
develop on the inner walls of
arteries.
2
▶ LDLs (low density lipoproteins)
Resources
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