Transcript Circulatory System

Circulatory System
2.01 Remember the structures of the circulatory system
2.02 Understand the functions and disorders of the
circulatory system
Components of the Circulatory
System
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Heart
Arteries
Veins
Capillaries
Blood and lymph
The Heart
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Hollow, muscular, double pump that
circulates blood.
At rest = 2 oz. blood with each beat, 5
qts./min., 75 gallons/hour.
Average= 72 beats per minute.
100,000 beats/day
Size of a closed fist
Heart
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Weighs 12-13 oz
Location – thoracic cavity
Apex – conical tip, lies on
diaphragm, points left
Stethoscope instrument used to
hear the heartbeat Heart sound is
lub dub.
Heart functions
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circulates blood to all parts of
the body
Arteries, veins, and capillaries
take blood from heart to cells
and return to heart
Carries O and nutrients to cells,
carries away waste products.
Lymph system returns excess
tissue fluid to general
circulation.
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Layers of the heart
Pericardium: double layer of fibrous tissue
that surrounds the heart
Myocardium: cardiac muscle tissue
Septum
Septum: partition (wall) that
separates right half from left half.
Pericardium
Myocardium
Endocardium
Endocardium: smooth inner lining of heart
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Heart
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Superior vena cava and inferior
vena cava bring deoxygenated
blood to the right atrium
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Pulmonary artery takes
deoxygenated blood away from the
right ventricle to the lungs for O2 .
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Pulmonary veins bring oxygenated
blood from the lungs to left atrium
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Aorta takes oxygenated blood
away from left ventricle to rest of
body.
Chambers and Valves
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Upper chambers: Right
and Left atrium
Lower chambers: right and
left ventricle
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the left ventricle wall is 3x as
thick as the right ventricle
wall and forms the apex of
the heart.
Four heart valves permit
flow of blood in one
direction
Valves
Tricuspid valve: between right
atrium and right ventricle
Bicuspid (mitral) valve: between
left atrium and left ventricle
Semilunar valves: located where
blood leaves the heart
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Pulmonary semilunar valve
Aortic semilunar
Blood and oxygen supply to the heart is from
the coronary arteries.
Heart
Aorta
Superior vena cava
Pulmonary artery
Aortic semilunar valve
Pulmonary vein
Right atrium
Left atrium
Tricuspid valve
Bicuspid (mitral) valve
Inferior vena cava
Pulmonary semilunar valve
Right ventricle
Left ventricle
Septum
Apex
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Flow of blood through the body
Right side
Superior vena cava
Inferior vena cava
Right atrium
Tricuspid valve
Right Ventricle
Pulmonary valve
Pulmonary artery
Lungs CO2 and O2
exchange
Left Side
Pulmonary vein
Left atrium
Bicuspid valve
Left ventricle
Aortic valve
Aorta
Body
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Conduction system of
heart beats
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circulatory system
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Control of Heart Contractions
SA (sinoatrial) node:pacemaker of the
heart.
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Located in the right atrium of the heart.
sends out electrical impulse
Impulse spreads over the atria, making
them contract
The impulse then travels to the AV
node
AV (atrioventricular) Node
Conducting cell group
between atria and ventricle
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Carries impulse to bundle
of His
Bundle of His
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Conducting fibers in
the septum
Divides into R and L
branches to network
of branches in
ventricles (Purkinje
fibers)
Purkinje Fibers
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Impulse shoots
along Purkinje fibers
causing the
ventricles to
contract.
Electrocardiogram (EKG or ECG)
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Device used to record the electrical activity
of the heart
Systole=contraction phase
Diastole= relaxation phase
P=atrial contraction
QRS=ventricular contraction
T=ventricular relaxation
Holter monitor=24hr. EKG
Baseline of an EKG is a flat line
Interpretation of EKG
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 P wave=enlarged atrium or stenosed
AV valve.
 Q wave= Myocardial infarction
 R wave= Enlarged ventricles
 T wave = K+ level too high
Major Blood Circuits
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General (systemic)
circulation
Cardiopulmonary
circulation
Circulation and Blood Vessels
Cardiopulmonary
Circulation
Systemic Arterioles Venules
Circulation
Heart and lungs From the Smallest
heart to
arteries
the tissues
and cells,
then back
to the
heart
Smallest
veins
Systemic Circulation
Aorta: largest artery in the
body
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First branch is coronary
artery
Aortic arch
Many arteries branch off
the descending aorta
Arteries
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Carry oxygenated blood
away from the heart to the
capillaries
Elastic, muscular and thickwalled
Transport blood under very
high pressure
Arterial blood – lots of
oxyhemoglobin = bright red,
spurts
Arteries > arterioles >
capillaries
Capillaries
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Smallest blood vessels, can
only be seen with a microscope
Connect arterioles with venules
Walls are one-cell thick and
extremely thin-allow for
selective permeability of
nutrients, oxygen, CO2 and
metabolic wastes
Veins
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Carry deoxygenated blood away from capillaries
to the heart
contain a muscular layer, but less elastic and
muscular than arteries
Thin walled, collapse easily when not filled with
blood
Valves permit flow of blood only in direction of the
heart
Jugular vein- located in the neck
Venous blood – lots of CO2, poor oxygen = dark
crimson, oozes
Veins > Venules > Capillaries
Blood Pressure-
is the surge of blood when the heart pumps
creating pressure against the walls of the arteries.
Systolic Pressure
Diastolic Pressure
Measured during the
contraction phase
Measured when the
ventricles are relaxed
Normal average
Normal average
systolic pressure= 120 diastolic pressure =80
Pulse
alternating expansion and contraction
of an artery as blood flows through it.
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Pulse sites
Temporal
External maxillary
Carotid
Brachial
Radial
Femoral
Popliteal
Posterior Tibial
Pedal
Common pulse sites
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