cardiovascular system Flashcards
pericardium
thick sac that protects the heart and anchors it to the diaphragm
the inner and outer layers of the pericardium are covered by a smooth layer of endothelium
a special lubricating fluid between the layers allows the heart to slide around with very little friction
myocardium
the bulk of the heart and composed mainly of cardiac muscle and is the layer that contracts
the myocardium muscle fibers are highly branched and attached by collagen connective tissue fibers that link all parts of the heart together
endocardium
the heart is lined with a white sheet of endothelium which is continuous with the blood vessel linings
fossa ovalis
marks a place of opening between the artria in developing fetuses
it allows fetal blood to move directly from the right to left atrium bypassing the lungs which are underdeveloped
This closes during birth so the baby can begin to breath on their own and recieve oxygen
pulmonary valve
controls the flow leaving the right ventricle into the pulmonary trunk
aortic valve
controls the flow of blood out of the left ventricle into the aorta
the aortic valve is stronger than the pulmonary valve because of the increased blood pressure needed to send blood pumping to the entire body.
mitral (bicuspid) valve
controls the flow of blood from the left atrium into the left ventricle
tricuspid valve
controls the floe of blood from the right atrium to the right ventricle
three types of blood vessels used to transport blood
arteries - carry blood away from the heart -except pulmonary
veins -carry blood back to the heart
capillaries - change materials with tissues
arteries
elastic, thick-walled vessels that can expand and contract to accommodate the larger blood flowing from the heart at the end of each heart beat
large arteries expand and recoil to help the heart pump blood through the systemic circulation
have palatable pulses
arterioles
small arteries are constricted and dilated by muscles controlled by the automatic and parasympathetic systems which control blood pressure
contracting the arterioles increase blood pressure through decreasing the available volume and relaxation decreases it
peripheral resistance
arterioles are the vessels primarily responsible for providing differing levels of peripheral resistance (varying blood pressure) to blood flow depending on the internal and external affecting the body
veins
are thinner walled vessels that are under less pressure from the heart
these do not have pulses
have internal valves that open toward the heart and close at the end of a heart beat to prevent blood from flowing backward as the blood is returned to the heart
compliance
veins have compliance which means they stretch with very little recoil
because of their compliance veins have the largest amount of blood in the CVS
lumen
the opening in the center of a vessel
three layers of arteries and veins
tunica externa, turnia media and tunica intima
tunica externa
most superficial layer of the artery or vein which helps anchor the vessel to the surrounding structures
turica media
middle muscular layer of a vessel has an external elastic membrane, a layer of smooth muscle, a layer of internal elastic membrane
tunica intima
innermost layer of a vessel that contains a layer of subendothelial tissue and a layer of endothelium
capillaries
branching of arterioles causes formation of even narrower tubes called capillaries.
these are interconnected to form capillary beds which perform gas exchange of materials with cells of the body
venules
the blood is collected from capillary beds by small veins called venules - many which join to form a vein to return blood to the heart
left coronary artery
runs towards the left side of the heart and divides the interventricular branch and the circumflex branch
anterior interventricular branch
supplies blood to both ventricles
circumflex branch
supplies the left atrium and left ventricle
right coronary artery
runs towards the right side of the heart and divides into posterior interventricular artery and marginal artery which supply the right atrium and right ventricle
circle of willis
also know as the cerebral arterial circle
has a unique feature of providing alternate circulation in case one of the arteries becomes blocked
this is important because neurons can only survive minutes without oxygen before they die
basilar artery
two vertebral arteries rise superiorly along both sides of the spinal cord joining to form the basilar artery at the base of the pons
the basilar artery branches into left and right posterior cerebral arteries
blood is classified as what and contains what
connective tissue
liquid portion called plasma
cellular portion called formed elements composed of red blood cells, white blood cells, and platelets
serum
is identical to blood but the clotting proteins have been removed
this is done by letting the blood sit in a tube until it clots and centrifuging the sample to seperate the solids from liquid portions
used for many laboratory tests
osmotic pressure
is the net pressure of blood that moves fluids from the tissues into the circulatory system
driven by proteins in the plasma that remain in the capillaries
in the case of blood at the capillaries, water has an automatic tendency to slow towards the proteins pulling fluids back into the circulatory system
opposed hydrostatic pressure
Functions of plasma
helps buffer the pH of blood keeping it near 7.4
helps in transporting large organic molecules in blood
aides in clotting
maintains blood osmotic pressure because of proteins in plasma
hydrostatic pressure
hydrostatic pressure of blood which pushes fluid into the tissues by the pressure of blood pumping from the heart
**It is important for the body to maintain homeostasis between osmosis and hydrostatic pressure so that fluids flow into the tissues and then return to the circulatory system
red blood cells (erythrocytes)
most abundant cell in the body.
small bioconcave discs that carry oxygen
each red blood cell has 250 million hemoglobin molecules
live for 120 days and destroyed by the liver and spleen
Hemoglobin
contains iron that loosely combines with oxygen helping to carry oxygen in the blood
Where are red blood cells manufactured
In red bone marrow of the skull, ribs, vertebrae, and the ends of long bones
Anucleate
without a nucleus - red blood cells must lose their nucleus and synthesize hemoglobin before they are released in the blood