Transcript CardiovascularSystemx - Phoenix Union High School District

The Transport System
AKA
The Cardiovascular System
Or
The Circulatory System
Stephen Taylor
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Stephen Taylor
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The Structure of the Heart
Stephen Taylor
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External Heart Anatomy
Internal Heart Anatomy
The Heart: Chambers
 Right and left side act
as separate pumps
 Four chambers
 Atria  Receiving chambers
 Right atrium
 Left atrium
 Ventricles
 Pumping chambers
 Right ventricle
 Left ventricle
The Heart:
Valves
 Allow blood to flow in

only one direction
Four valves
 Atrioventricular valves
– between atria and
ventricles
 Bicuspid valve
(left)
 Tricuspid valve
(right)
 Semilunar valves
between ventricle and
artery
 Pulmonary
semilunar valve
 Aortic semilunar
valve
Valves open as blood is pumped through
Held in place by chordae tendineae (“heart strings”)
Close to prevent backflow
The Heart: Associated Great
Vessels
 Aorta
 Leaves left ventricle
 Pulmonary arteries
 Leave right ventricle
 Vena cava
 Enters right atrium
 Pulmonary veins (four)
 Enter left atrium
Stephen Taylor
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Stephen Taylor
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Blood Flow
Stephen Taylor
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Stephen Taylor
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Two drops of blood are shown with a
bright red oxygenated drop on the left
and a deoxygenated drop on the right.
Stephen Taylor
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Vessels
© Kevin Petti, Ph.D. Departments of Natural
Sciences
Health, Exercise Science & Nutrition
San Diego Miramar College
Cardiac Vessels
Coronary Circulation
 Blood in the heart
chambers does not
nourish the
myocardium
 The heart has its own
nourishing circulatory
system
 Coronary arteries
 Cardiac veins
Heart Attack: A Block of one of
these arteries that cause the
muscle cells to die.
One treatment is a bypass surgery
http://www.hhmi.org/biointeractive/obesity/heart_attac
k.html
Stephen Taylor
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The Cardiac Cycle – “Heartbeat”
The Heart: Cardiac Cycle
Cardiac cycle – events of one
complete heart beat
 Atria contract simultaneously
 Atria relax, then ventricles contract
 Systole = contraction; aortic valve is OPEN
 Diastole = relaxation; aortic valve is CLOSED
The Heart: Cardiac Cycle
Diastole
• The heart muscle is relaxed
this is called diastole.
• There is no pressure in the
heart chambers.
• Blood tries to flow back into
the heart but closes the semilunar valves.
The Heart: Cardiac Cycle
Diastole
• Both atria fill with blood returning to the
heart in the veins.
• The right atrium fills with blood returning in
the vena cava from the body tissues
(deoxygenated).
• The left atrium fills with blood returning
from the lungs (oxygenated).
• The atrio-ventricular valves are still closed
and the atria fill up.
The Heart: Cardiac Cycle
Late Diastole
• In this diagram the heart is still
relaxed (diastole).
• The pressure of blood returning to
the heart and filling the atria is now
high enough to open the atrioventricular valves.
• The pressure in the atria is greater
than the pressure in the ventricles.
• Atrio-ventricular valves open.
• Ventricles begin to fill with blood.
The Heart: Cardiac Cycle
Atrial systole
• Both atria contract together (see
control of heart rate)
• The muscles of the atria contract.
• Volume of the atria reduces.
• Pressure of blood increases.
• Blood flows into the ventricles,
filling these chambers and causing
the ventricle walls to stretch.
The Heart: Cardiac Cycle
Ventricular Systole
• The ventricle contracts (systole)
• The pressure increases in the
ventricle
• The atrio-ventricular valve closes
• The pressure rises further
• Pressure in the ventricle is greater
than the artery, semi-lunar valve
opens
• Blood pulses into the arteries
The Heart: Cardiac Cycle
Blood Pressure
Blood Pressure
Measurements by health
professionals are made
on the pressure in large arteries
 Systolic – pressure at the peak of
ventricular contraction
 Diastolic – pressure when ventricles relax
 Pressure in blood vessels decreases as
the distance away from the heart
increases
Measuring Arterial Blood
Pressure
Variations in Blood Pressure
 Human normal range is variable
 Normal
 140–110 mm Hg systolic
 80–75 mm Hg diastolic
 Hypotension
 Low systolic (below 110 mm HG)
 Often associated with illness
 Hypertension
 High systolic (above 140 mm HG)
 Can be dangerous if it is chronic
Control of the Heartbeat
Regulation of the Heartbeat
 The contractions of the cardiac
muscles are myogenic (they
originate within the heart muscle).
 The nerve impulses do NOT
originate in the brain, but from
within a region of the right atrium
called the Sino-Atrial Node (SA
node).
 SA node is also called the
pacemaker.
 This causes the muscle cells to
contract at regular intervals.
Regulation of the Heartbeat
• The impulse from
the SA node
speads to the
Atrio-Ventricular
node (AV node).
• It spreads down
to the apex.
• Then it spreads
upward, causing
the ventricles to
contract and push
blood up into the
arteries.
Regulation of the Heartbeat
• The heart is mostly
autonomous.
• The brain does influence
the frequency of the
heartbeats.
• Impulses from the lower
part of the brain stem
(medulla) can either
increase or decrease the
heartbeat.
Regulation of the Heartbeat
• Hormones also affect
heart rate.
• Adrenaline (epinephrine)
from the adrenal glands
increases heart rate.
• “Fight or Flight response”
Regulation of the Heartbeat
• If the SA node does not work
properly, it is possible to implant an
artificial pacemaker.
Blood Vessels: The Vascular System
 Taking blood to the tissues and back
 Arteries
 Capillaries
 Veins
Blood Vessels: Arteries
 they take blood AWAY from the heart at high
speeds (10-40 cm/sec).
 They have muscular walls, but no valves.
 A collagen layer resists expansion
 Muscle contracts to maintain high pressure
all the way to the tissues.
VAn 308-Functional Anatomy
Arteries
Blood Vessels: Veins
 they take blood TO the heart at moderate
speeds (5-20 cm/sec).
 They have the largest lumen.
 They have valves to prevent backflow.
 They operate under low pressure to
reduce resistance to blood flow.
Veins
© Kevin Petti, Ph.D. Departments of Natural
Sciences
Health, Exercise Science & Nutrition
San Diego Miramar College
Blood Vessels: Capillaries
 they are the location where blood can
exchange material with tissues.
 They are only one cell thick
 They move blood very slowly (<0.1 cm/sec)
The Vascular System
Major Arteries of Systemic
Circulation
Major Veins of Systemic Circulation
Capillary Beds
 True capillaries –
exchange vessels
 Oxygen and
nutrients cross to
cells
 Carbon dioxide and
metabolic waste
products cross into
blood
Blood Circulation
Blood
Blood
The only fluid tissue in the
human body
By weight, it’s about 8% of
the human body.
Living cells
45-50%
Non-living plasma
50-55%
Type of Blood Cells
Blood Plasma
 Composed of approximately 90 percent
water
 Includes many dissolved substances
 Nutrients
 Salts (metal ions)
 Respiratory gases
 Hormones
 Proteins
 Waste products
Cells
 Erythrocytes = red blood cells
 Leukocytes = white blood cells
 Thrombocytes = platelets
Erythrocytes (Red Blood Cells)
 The main function is to carry
oxygen
 Anatomy of circulating
erythrocytes
 concave disks
 Essentially bags of
hemoglobin
 Have no nucleus
 Contain very few
organelles
 Make up 90% of blood cells
Hemoglobin
 Iron-containing protein
 Binds strongly, but
reversibly, to oxygen
 Each hemoglobin molecule
has four oxygen binding
sites
 Each erythrocyte has 250
million hemoglobin
molecules
Two drops of blood are shown with a
bright red oxygenated drop on the left
and a deoxygenated drop on the right.
Fate of Erythrocytes
 Unable to divide, grow, or synthesize
proteins
 Wear out in 100 to 120 days
 When worn out, are eliminated by
phagocytes in the spleen or liver
 New erythrocytes are made in the bone
marrow
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Slide
10.15
Leukocytes (White Blood Cells)
 Crucial in the body’s
defense against disease
 These are complete cells,
with a nucleus and
organelles
 They only live 3-4 days.
Types of Leukocytes
 Phagocytes – a nonspecific type of white
blood cell that protects
the body by ingesting
harmful or dead
material.
 They help fight
infection.
 In large numbers, they
look like pus.
Figure 10.4
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
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10.10a
Types of Leukocytes
 Lymphocytes – a
specific type of white
blood cell that
produces antibodies to
fight specific antigens.
Figure 10.4
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Slide
10.10a
Platelets
 Fragments with no nuclei
 Last 5-9 days
 Needed for the clotting process
Blood Clotting
 Blood usually clots within 3 to 6 minutes
 The clot remains as endothelium
regenerates
 The clot is broken down after tissue
repair
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
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10.22
Undesirable Clotting
 Thrombus
 A clot in an unbroken blood vessel
 Can be deadly in areas like the heart
 Embolus
 A thrombus that breaks away and floats
freely in the bloodstream
 Can later clog vessels in critical areas such
as the brain
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
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10.23
Bleeding Disorders
 Thrombocytopenia
 Platelet deficiency
 Even normal movements can cause
bleeding from small blood vessels that
require platelets for clotting
 Hemophilia
 Hereditary bleeding disorder
 Normal clotting factors are missing
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
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10.24
Closure
Name one thing you learned about the
transport system.
 What’s one thing you’re still confused
about.
 What’s something you would like more
information about.
