Transcript The Cardiovascular System

The Cardiovascular System
The cardiovascular system consists of the heart and
blood vessels (arteries, capillaries and veins.)
• Supplies oxygen and nutrients to tissues, removes
wastes
• Pulmonary circuit carries deoxygenated blood to the
lungs to release CO2 and pick up O2
• Systemic circuit sends oxygenated blood to cells of the
body and picks up CO2 from cells.
The systemic circuit delivers oxygen to all
body cells and carries away wastes.
The pulmonary circuit eliminates carbon
dioxide via the lungs and oxygenates the
blood.
Deoxygenated blood
Oxygenated blood
O2
O2
CO2
Oxygenated
blood pumped to
all body tissues
via aorta
O2
CO2
Deoxygenated
blood pumped
to lungs via
pulmonary arteries
CO2
CO2
CO2
O2
CO2
CO2
O2
O2
CO2
O2
Alveolus
O2
Oxygenated blood returns
to heart via pulmonary veins
Deoxygenated blood returns
to heart via venae cavae
Left atrium
Right atrium
Right ventricle
Left ventricle
The Heart
• Pericardium is a dense fibrous connective tissue
covering the heart ( sac around the heart)
• 3 distinct layers underneath pericardium
– epicardium-contains coronary arteries and vessels
that nourish the heart
– myocardium- contains heart muscle tissue
– endocardium-contains Purkinge fibers that innervate
the heart
Pericardial
cavity
Parietal
pericardium
Fibrous
pericardium
Endocardium
Myocardium
Epicardium
(visceral pericardium)
Coronary
blood vessel
Chambers of the Heart
• 4 chambers
– 2 thin walled atria that receive blood from the body
• Right atrium receives deoxygenated blood from the
body
• Left atrium receives oxygenated blood from the
lungs
– 2 thick walled ventricles that pump blood to the body
• Right ventricle pumps deoxygenated blood to the
lungs
• Left ventricle pumps oxygenated blood to the body
Systemic
capillaries
Tissue cells
CO2
Superior
vena cava
O2
Pulmonary
artery
Alveolus
CO2
CO2
Alveolar
capillaries
O2
O2
Alveolar
capillaries
Alveolus
Pulmonary
veins
Right atrium
Tricuspid valve
Pulmonary valve
Right ventricle
Inferior vena cava
Left atrium
Mitral valve
Left ventricle
Aortic valve
Aorta
CO2
Systemic
capillaries
O2
Tissue cells
Right lung
Left lung
Aorta
Superior
vena cava
Pulmonary trunk
Diaphragm
Left auricle
Cut edge of
fibrous pericardium
Right auricle
Right atrium
Cut edge of
parietal pericardium
Heart (covered by
visceral pericardium)
Left ventricle
Right ventricle
Pericardial cavity
Valves
• Pulmonary Valve -prevents backflow of blood into the
right ventricle as blood is pumped to lungs
• Aortic valve -prevents backflow of blood into the left
ventricle
• Right Atrioventricular valve (AV) (tricuspid)-prevents
backflow of blood into the right atrium from the ventricle
• Left Atrioventricular valve (bicuspid or mitral valve)prevents backflow of blood into the left atrium from the
ventricle
Anterior View of Heart
Aorta
Superior vena cava
Left pulmonary artery
Right pulmonary
artery
Pulmonary trunk
Left pulmonary veins
Right pulmonary
veins
Left auricle
Left coronary artery
Right auricle
Great cardiac vein
Anterior interventricular artery
(left anterior descending artery)
Right coronary
artery
Anterior cardiac vein
Small cardiac vein
Inferior vena cava
Left ventricle
Right ventricle
(a)
Apex of the heart
Fig13.09b
Posterior View of Heart
Superior vena cava
Right pulmonary
artery
Aorta
Left pulmonary artery
Left pulmonary
veins
Right pulmonary veins
Left auricle
Circumflex artery
Left atrium
Cardiac vein
Right atrium
Inferior vena cava
Coronary sinus
Middle cardiac vein
Left ventricle
Posterior interventricular
artery
Right ventricle
(b)
Apex of the heart
Systole/Diastole
11
The Cardiac Cycle
• Atrial Systole- contracting atria, relaxing
ventricles.
• Ventricular systole –contracting
ventricles, relaxing atria
• Diastole- when the entire heart is relaxing
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Valves and Contractions of the
Heart
Pulmonary
valve closed
Aortic
valve closed
Pulmonary
valve open
RA
Aortic
valve open
LA
Atrial systole
Atrial diastole
Tricuspid
and mitral
valves open
(a)
LV
RV
Ventricular
diastole
Tricuspid
and mitral
valves closed
(b)
Ventricular
systole
Heart Sounds
• Due to vibrations in heart tissues as blood
rapidly changes velocity within the heart.
• Heart sounds can be described as a "lubbdupp" sound.
• First sound (lubb) -ventricles contract and AV valves are closing
• Second sound (dupp)-ventricles relax and
aortic and pulmonary valves are closing.
Electrocardiogram
• An electrocardiogram (ECG) is a recording of
the electrical changes that occur during a
cardiac cycle.
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Electorcardiogram
(a)
1.0
R
Millivolts
.5
T
P
0
Q
–.5
S
0
(b)
200
400
Milliseconds
600
Blood Pressure
• Blood pressure -force of blood against inner walls of
blood vessels anywhere in the cardiovascular
system.
– As blood gets further and further from the left ventricle, blood
pressure decreases.
• Pulse-The surge of blood that occurs with ventricular
contraction and can be felt at certain points in the
body.
– Caused by the expansion and contraction of blood vessels
• Systolic pressure- During ventricular contraction,
arterial pressure is at its highest.
• Diastolic pressure- When ventricles are relaxing,
arterial pressure is at its lowest.
Normal blood Pressure= 120/80 or less
Taking Blood Pressure
•
•
•
•
Subject is seated and relaxed.
Wrap the fabric cuff around the upper arm
Locate the brachial artery
Place the diaphragm of the stethoscope over the
brachial artery so that you can hear Kortokoff
sounds
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Taking Blood Pressure
• Close the valve and pump air until the pressure
reads 180mmHg.
• Open the valve of the bulb slowly until the
pressure in the cuff drops at a rate of about 2 or
3 mm Hg per second.
• Listen for the sounds from the brachial artery-1st
loud tapping sound=systolic pressure.
• When sounds suddenly are muffled= diastolic 20
pressure.