Transcript Cardiovascular System PPT - Effingham County Schools

Chapter 15
Cardiovascular System
Organs
• Heart - begins beating in the 4th week of
development.
– Pumps 7,000 liters of blood each day.
– Contracts 2.5 billion times in a lifetime.
• Closed Vessel System
– Arteries - carry blood away from the heart.
– Veins - carry blood toward the heart.
– Capillaries - attach arteries and veins.
Function
• Circulates blood to every cell in the body
and removes waste.
The Heart
• Location and Size
– Size of a man’s fist (14
cm long and 9 cm wide)
– Lies within the
mediastinum - behind
sternum (rests on
diaphragm).
– 2/3 of the heart is on the
left side of the body.
– Apex is the lower, left
“point” of the heart.
• Stethoscope is placed here
to count the beats.
•
The Heart
Coverings
–
Pericardium - sac around
the heart - loose-fitting
•
•
–
Epicardium - covers surface
of the heart - smooth
•
–
Fibrous - tough white outer
covering,
Serous parietal - smooth
lining of the fibrous sac.
Also called serous visceral
pericardium
Pericardial space - area
between pericardium and
epicardium
•
•
•
Contains fluid - pericardial
fluid
Lubricates beating heart
Pericarditis - inflammation
of pericardium due to
infection - linings stick
together, very painful.
The Structure of the Heart
• The wall of the heart:
– Epicardium – reduces
friction.
– Myocardium – thick
contractile middle layer,
high in mitochondria.
– Endocardium – delicate
inner layer.
The Structure of the Heart
Continued
• Cavities
– Upper – atria
– Lower – ventricles
• Larger and thicker
walled
• Carry heavier pumping
burden
• Left is thickest – has to
pump blood to all parts
of the body
The Structure of the Heart
Continued
• Valves and Openings
• Blood flows in one direction.
– Cuspid valves – between
cavities.
• Bicuspid (mitral) valve left cavities.
• Tricuspid valve - right
cavities.
– The semi-lunar valve moves
blood out of the heart to the
aorta and pulmonary artery.
– A murmur is an abnormal
sound that identifies the
leakage of blood through
valves in the wrong direction.
The Structure of the Heart
Continued
• Blood Supply
– Ventricles get blood from the right and left
coronary arteries.
– Atria get blood from the small branch
coronary artery.
– Anastomosis is branching of the main arteries
“detours”
– Myocardial infarction - death of the heart
muscles due to a clot (heart attack).
Blood Vessels
• Structure
– Outer – fibrous tissue,
keeps firm
– Middle – muscle,
constriction, and dilation.
– Inner – endothelium capillaries
Blood Vessels Continued
• Function
– Transportation of nutrients to cells
• Capillaries perform this function
• Arteries = distributors arterioles
venules veins
• Veins = carry and pool blood
capillaries
Blood Vessels Continued
• Main Blood Vessels
–
–
–
–
–
ascending aorta
aortic arch
subclavian
common carotid
common iliac
Ascending
Aorta
Blood Vessels Continued
Blood Vessels Continued
• Portal Circulation
– Organs that do not pour blood into inferior
vena cava.
– Blood sent to the liver by the portal vein.
Blood Vessels Continued
• Fetal Circulation
– Gets oxygen and food from mother, not own
lungs and digestive tract.
– Additional vessels
Shed at
birth
• Umbilical arteries (2) – carry fetal blood to
placenta
• Placenta – exchanges oxygen and other
substances between mother and fetus
• Umbilical vein – returns oxygenated blood to liver
of fetus
• Foramen ovale – opening between right and left
atria bypass lungs, closes with first breath.