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231 terms

PCOM: Anatomy 2 - combo set - The Cardiovascular System: The Heart, Blood Vessels and The Lymphatic System

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the three layers of the blood vessel walls, internal to external
tunica intima, tunica media, tunica externa
three layers of the tunica intima, internal to external
endothelium, sub-endothelial layer, internal elastic lamina
function of the tunica intima
reduces friction between the vessel walls and the blood
layer of the tunica intima that is not found in veins
internal elastic lamina
the basal membrane of the blood vessels
the sub-endothelial layer
function of the internal elastic lamina
elasticity for arteries due to arterial pressure (high pressure system)
composition of the tunica media
smooth and elastic muscles and the external elastic lamina
differences in the tunica media in arteries and veins
thinner in veins as it is a low pressure system
two layers of the tunica media in arteries
muscle layer and the external elastic lamina
function of the tunica media
controls vasodilation and vasoconstriction
composition of the tunica externa
collagen fibers
function of the tunica externa
protects, reenforces, and anchors the vessel to surrounding structures
feature of vessel structure found in veins only
internal, one way venous valves that are covered in endothelium
function of the venous valves
to prevent back flow of blood as it returns to the heart - found mostly in the extremities
how blood returns to the heart against gravity
the muscles of the leg pump it up as constricting occurs during use (e.g. walking)
how blood form the abdominopelvic region returns to the heart
the respiratory pump - contraction of the diaphragm creates high pressure in the lower region and low pressure in the upper region, causing blood to be drawn upward
the largest arteries as they lead away from the heart
elastic or conducting arteries
physical characteristic of conducting arteries allowing them to withstand changes in arterial pressure due to the heart action
contain large amounts of elastin, creating elasticity
second level of arteries
muscular or distributing arteries
function of muscular or distributing arteries
deliver blood to specific organs and very active in vasoconstriction
important physical characteristic of muscular or distributing arteries
they contain the largest tunica media of all arteries due to greater muscle content for vasoconstriction
smallest arteries
arterioles
function of the arterioles
regulate blood flow into the capillary beds through vasoconstriction and vasodilation
important physical characteristic of arterioles
the muscle layer of the tunica media is made of smooth muscle only
physical characteristic of the capillaries
they are the smallest vessels
function of the capillaries
they allow the exchange of substances between the vessels and the interstitial fluid
continuous capillaries
contain no muscle, the capillary wall is one cell thick with a basement membrane, and are the least permeable and most common capillary; still allow the passage of fluids and small solutes
fenestrated capillaries
contain fenestrations (small pores) and are more permeable than continuous capillaries and are found in specialized locations like the kidneys and small intestine
sinusoidal capillaries
the most permeable capillaries allowing large molecules to pass through; found in the liver, spleen and bone marrow
where the smallest capillaries are found
in the spleen - sinusoidal
structure at the end of the arterial circulation
capillary beds
structure of the capillary beds
microcirculatory network with a vascular shunt and the true capillaries that act as exchange vessels
structure at the entry point for the capillary beds
pre-capillary sphincter
function of the pre-capillary sphincter
regulates the flow of blood through the capillary bed
structure of the pre-capillary sphincter
a cuff of smooth muscle surrounding each capillary at the metarteriole
blood flow when the pre-capillary sphincter is open
blood flows into the capillary bed allowing the plasma to leave the blood into the interstitial spaces with nutrients, etc for the tissues/cells they supply
blood flow when the pre-capillary sphincters are closed
blood passes through the vascular shunt, bypassing the capillary bed without release plasma and its solutes
where the plasma released into the interstitial fluids returns to the blood
in the venous side of the capillary bed - the beginning of venous system
percentage of plasma that is not returned to the blood by capillary re-uptake
1%
where the capillaries converge
venules - allow fluid and WBCs to move easily between the blood and tissues
what venules form as they converge
veins
physical characteristics of veins
thin walled with relatively large lumens
additional term for small and large veins
capacitance vessels
function of veins as capacitance vessels
store blood - 65% of the blood in the body is in the venous system at any given time
venous response when blood pressure drops
vasoconstriction - increases the blood volume in the arterial system
percentage of blood in systemic circulation at any given time
84%
vascular anastomoses
where vascular channels unite forming alternative blood pathways to allow blood supply and drainage from an area even if one channel is blocked
blood pressure
measured in arteries - the force per unit area exerted by the blood on the blood walls expressed in millimeters of mercury
effect of High Blood Pressure
damages the endothelium of the vessels leading to atherosclerosis
how blood pressure results
the resistance of the blood during the pumping action of t heart
blood pressure levels throughout the systemic circuit
highest in the aorta, decreasing throughout the pathway until is reaches 0 in the right atrium
cardiac output
the amount of blood ejected from the ventricle each minute CO = SV (stroke volume) x HR (heart rate)
stroke volume
the amount of blood ejected by the ventricle on each contraction
what arterial Blood pressure signifies
how much the arteries close to the heart can be stretched (compliance or distensibility) and the volume of blood forced into them at any given time
systolic pressure
the peak pressure created when the left ventricle contracts forcing blood into the aorta (normally about 120mm Hg)
diastolic pressure
the pressure created when back flow into the ventricles is prevented by the semilunar valves (normally about 70-80 mm Hg)
characteristics of where arteries run
deep and are well protected
characteristics of where veins run
both deep (parallel to the arteries) and superficial (just under the skin
number of terminal systemic arteries
one - the aorta
number of terminal systemic veins
two - inferior and superior vena cava
three parts of the aorta
ascending aorta, arch of the aorta, thoracic aorta
the 4 paired arteries of the head and neck
costocervical trunk, thyrocervical trunk, vertebral artery, common carotid artery
from where the left common carotid artery arises
from the aortic arch
from where the right common carotid arises
from the brachiocephalic trunk as it branches from the aortic arch
two branches of the common carotid
the external and internal
area the internal carotid supplies
major supplier of blood to the brain
area the external carotid supplies
the scalp, face, larynx and some of the thyroid
from where the vertebral arteries arise
subclavian artery, the first and most medial branch
area the vertebral artery supplies
passes through the transverse processes of the cervical spine and supplies the brain
from where the thyrocervical artery arises
subclavian artery, lateral to the vertebral arteries
area the thyrocervical trunk supplies
thyroid gland and portions of the cervical spine
from where the costocervical artery arises
subclavian artery, lateral to the thyrocervical arteries
area the costocervical artery supplies
deep neck muscles
the three branches of the aortic arch from right to left
the brachiocephalic trunk, the left common carotid, the left subclavian
the two branches of the brachiocephalic trunk medial to lateral
the right common carotid, the right subclavian
area supplied by the subclavian arteries
the upper extremities
pathway of the subclavian arteries
becomes the axillary artery at the armpit, the brachial artery at the elbow and the radial and ulnar arteries at the wrist
from where the left and right coronary arteries arise
the ascending aorta
artery that supplies the abdomen
the abdominal aorta
from the where the abdominal aorta arises
from the thoracic aorta as it passes through the aortic hiatus in the diaphragm
most proximal artery that supplies the lever, stomach and spleen
celiac trunk
artery that supplies intestines, rectum and tissues
superior and inferior mesenteric arteries
from where the mesenteric arteries arise
the abdominal aorta
artery that supplies the kidneys
the renal artery
from where the renal arteries arise
between the superior and inferior mesenteric arteries off the abdominal aorta
arteries that supply the pelvis and lower extremities
the common iliac arteries
from where the common iliac arteries arise
the abdominal artery bifurcates at around the iliac crest/L-4 level, forming the right and left common iliac arteries
how blood supply moves to the pelvis
the common iliac bifurcates and the pelvis and pelvic organs are supplied by the internal iliac artery
how blood supply moves to the lower extremities
the common iliac bifurcates and the external iliac artery supplies the lower extermities
pathway of the external iliac arteries
becomes the femoral artery in the thigh, has multiple branches at the knee
area from which blood drains to the superior vena cava
head, neck, upper extermities
area from which blood drains to the inferior vena cava
the trunk and lower extremities
area from which blood drains to the coronary sinus
the heart
three pairs of veins to which blood drains from the head and neck
external jugular, vertebral, and internal jugular
area from which blood drains to the external jugular
scalp and face
area from which blood drains to the vertebral veins
the brain
area from which blood drains to the internal jugular
the brain
the area to which the external vein drains
the subclavian vein
area to which the subclavian, vertebral and internal jugular drain
the brachiocephalic branch bilaterally
area to which the brachiocephalic veins drain
the merge and become the superior vena cava
pathway by which the blood of the thoracic wall and tissues are drained
the accessory hemi-azygos veins to the hemi-azygos veins, which merge to the azygos vein which drains to the superior vena cava
pathway by which the abdominal viscera and abdominal walls drain
through the portal system - the splenic vein drains the spleen and merges with the superior mesenteric vein to become the hepatic portal vein which transports blood to the two lobes of the liver for the storage of unused nutrients which then drains the blood to the inferior vena cava via the Right and left hepatic veins
to where the inferior mesenteric circulation drains
to the splenic vein
pathway by which the blood drains from the pelvis and pelvic organs
via the internal iliac vein which merges with the external iliac vein to form the common iliac vein to the inferior vena cava
pathway by which the blood drains from the lower extremities
lower limbs via several veins to the femoral vein in th thigh to the external iliac vein which merges with the internal iliac vein to form the common iliac vein which feed to the inferior vena cava
function of the lymph system
takes up the 1% of the plasma that is not reabsorbed by the venus capillaries in the capillary beds during circulation and cleans it
flow of the lymphatic system
one way to the heart
beginning of the lymph system
lymph capillaries between the tissue cells and the blood capillaries in the loose CT - these are blind ends (not circular)
to where the lymph capillaries feed
to the lymph collecting vessels
to where the lymph collecting vessels feed
to the lymph trunks
to where the lymph trunks feed
the lymph trunks drain large areas of the body and feed to the thoracic duct and the right lymphatic duct
lymph nodes
collections of WBCs along the lymph collecting vessels and lymph ducts that clean the plasma
areas drained by the right lymphatic duct
head, neck, right trunk and the right upper extremities
pathway of the right lymphatic duct
drains to the right subclavian vein
areas drained by the thoracic duct
the majority of the lymph system, excluding the head, neck, right trunk, and right upper extremities
size and weight of the heart
fist sized; about 250-300g
location of the heart
mediastinum 2/3 lies left of the mid-sternal line
orientation of the top of the heart
the base of the heart points to the right shoulder
orientation of the bottom of the heart
the apex points toward the left hip
the covering of the heart
double layered pericardium
outer layer of the pericardium
loose fibrous pericardium
make-up of the fibrous pericardium
dense CT
function of the fibrous pericardium
protects and anchors the heart
inner layer of the pericardium
serous pericardium
make-up of the serous pericardium
thin, slippery two layered serous membrane
two layers of the serous membrane
parietal pericardium and visceral pericardium or epicardium
location of the parietal pericardium
lines the inside of the fibrous pericardium
location of the epicardium
covers the surface of the heart
area between the parietal pericardium and epicardium
pericardial cavity
structure of the pericardial cavity
filled with serous fluid
function of the serous fluid in the pericardial cavity
to provide lubrication for the serous membranes to allow smooth movement during contraction and relaxation of the heart
three layers of the heart wall outer to inner
epicardium, myocardium, endocardium
structure of the epicardium
serous membrane lining the outer wall of the heart
structure of the myocardium
composed mainly of cardiac muscle and forms the bulk of the heart
endocardium
epithelial inner layer of the heart wall lining the chambers and valves of the heart
function of the endocardium
blood comes into contact with endocardium and enters the tissue
functions of the right atrium
receives the blood venous blood returning from the body through three veins
characteristic of venous blood
low oxygen content
three veins entering the right atrium
superior vena cava, inferior vena cava, coronary sinus
function of the superior vena cava
returns blood from the head, neck and upper extremities
function of the inferior vena cava
returns blood from the trunk and lower extremities
function of the coronary sinus
all veins from the heart drain into the coronary sinus which drains the coronary blood back to the right atrium
two networks in the heart
upper and lower
upper network of the heart
R & L atria
lower network of the heart
R & L Ventricles
how the upper and lower network interact
when one is performing a function, the other is doing the opposite
where the blood goes from the R atrium
passes to the right ventricle passing the tricuspid valve
function of the tricuspid valve
prevents back flow of blood from the right ventricle to the right atrium; closes when the ventricles contract and opens when they relax
functions of the right ventricle
pumps blood to the pulmonary trunk via the pulmonary valve
function of the pulmonary valve
to prevent back flow of blood from the pulmonary trunk to the right ventricle; opens when the right ventricle contracts and closes when blood fills the cusps in the valve, forcing it closed
name for blood circulation from the heart to lungs and back
pulmonary circulation
structure of the pulmonary trunk
bifurcates into the left and right pulmonary arteries
characteristics of the pulmonary arteries
only arterial flow in the body with low-oxygenated blood; bilateral set (2)
functions of the left atrium
receives oxygenated blood from the lungs via the pulmonary veins
characteristics of the pulmonary veins
only venous flow in the body with highly oxygenated blood; bilateral paired veins (4)
where the blood goes from the left atrium
passes to the left ventricle through the bicuspid or mitral valve
function of the mitral valve
prevents back flow from the left ventricle to the left atrium; closes when the ventricle contracts and opens when the ventricle relaxes
function of the left ventricle
pumps blood to the aorta via the aortic valve
function of the aortic valve
prevents back flow from the aorta to the left ventricle; closes when blood fills the cusps in the valve, forcing it closed
name of the blood circuit from the heart to the lungs and back
pulmonary circuit
name of the blood circuit from the heart to the body and back
systemic circuit
physical characteristic of the left ventricle
more muscle because it pumps blood into the high pressure systemic circuit
physical characteristic of the right ventricle
less muscle as it pumps blood into the low pressure pulmonary circuit
name for the aortic and pulmonary valves
semilunar valves
name for the tricuspid and bicuspid valves
atrioventricular valves
name of the tendons anchoring the AV valves in place
chordae tenidinae
function of the chordae tendonae
prevent the AV valves from opening the wrong way
how blood is pumped through the heart
the right side pumps blood into the pulmonary circuit and the left side simultaneously pumps blood into the systemic circuit
what provides blood supply to the heart
the coronary circulation
why separate blood supply necessary for the heart
because no nutrients pass from the blood as it passes through the chambers of the heart
from where the right and left coronary arteries arise
ascending aorta
path of the left coronary artery
bifurcates into the circumflex artery and the anterior inter-ventricular artery
to what part of the heart the circumflex artery supplies blood
the left atrium
to what part of the heart the anterior inter-ventricular artery supplies blood
the anterior ventricles
the path of the circumflex and anterior inter-vertricular arteries
from the left coronary artery then to the apex of the heart where it merges with the right coronary artery and supplies the right atrium and ventricle
path of the right coronary artery
branches at the right marginal artery and continues and branches at the posterior inter-ventricular artery then passes to the apex of the heart where it merges with the circumflex and anterior inter-ventricular arteries and supplies the right atrium and ventricle
to what part of the heart the right marginal artery supplies blood
to the anterior right ventricle
to what part of the heart the posterior inter-ventricular artery supplies blood
the posterior ventricles
to where blood from the heart drains
cardiac viens
where the cardiac veins drain
to the coronary sinus
coronary artery in which blockage is likely to lead to heart attack
left coronary artery or left inter-ventricular artery
what is the cause of myocardial infarction
blockage in the coronary arteries - particularly the left or left inter-ventricular
a sign that the AV valves in the heart are not closing all the way or may be damaged
murmur
structure of cardiac muscle
striated, skeletal muscle
mechanics of contraction of cardiac muscle
sliding filament method
characteristics of cardiac muscle cells
short, fat, branched and interconnected by intercalated discs
how some cardiac muscle cells are stimulated
self-stimulated
how the heart contracts
all or none - it does not contract by individual motor units
significance of the cardiac muscles' refractory period
longer than skeletal muscle (250 ms vs 1-2 ms) to prevent tectonic contractions
importance of O2 supply to the heart
the heart relies on aerobic respiration
nutrient supply in the heart
the heart is capable of switching metabolic pathways to use whatever nutrient supply is available
relative importance of nutrient vs O2 supply in the heart
O2 more critical due to the heart's need to function aerobically and its metabolic flexibility
autorhythmicity
the myocardium is the contractile muscle, however a portion is specialized to create electronic impulses to stimulate contraction
percentage of specialized myocardium that initiates and transmits electrical impulses throughout the heart
1%
where the electrical impulse initiate in the heart
the sino-atrial (SA) node
where the electrical impulse goes from the SA node
concurrently to the atria and the atrio-ventricular node (AV node)
where the SA and AV node are located
the right atrium
which are the most important chambers of the heart
the ventricles as they are responsible for the pumping of blood
how the ventricles are stimulated to contract and pump blood
electrical impulses from the SA and AV nodes
where the impulse from the AV node travels
the Bundle of His
location of the Bundle of His
in the inter-ventricular septum which divides the ventricles
where the impulse from the Bundle of His travels
branches into the Right and Left Bundle Branches
where the impulse travels from the Right and Left Bundle Branches
to the Purkinje Fibers
pathway of the Purkinje fibers
down the inter-ventricular septum to the apex of the heart, then upward to the walls of the ventricles; these go right into the papillary muscles
structure of the intrinsic conduction system
specialized cardiac muscle cells that initiate and distribute impulses ensuring orderly electrical impulses in the heart
complete chain of impulses in the heart
SA node, AV node, Bundle of His, Right and Left Bundle Branches, Purkinje Fibers
electrical characteristic of the SA node
unstable resting potential which generates the electrical impulse of the heart
name of the unstable resting potential in the SA node
pacemaker potential
interaction of the autonomic nervous system with the heartbeat
the sympathetic system speeds up and deepens contractions, and the parasympathetic slows them down
function of an electrocardiograph
monitors and records the electrical signals of the heart and records them
how the electrical signals of the heart are recorded
as an electrocardiogram (ECG or EKG)
contracting phase of the heart
systole
relaxing/filling phase of the heart
diastole
coordination of the atria and ventricles in contraction
the upper and lower networks act in unison - atria contract together and the ventricles contract together
term for the atria contraction
atrial systole
term for ventricular relaxation/filling
ventricular diastole
term for the ventricles contracting
ventricular systole
term for the atria relaxing/filling
atrial diastole
S1
the first heart sound "lub" - it is the sound of the AV valves closing at ventricular systole
S2
the second heart sound "dub"- the sound of the semilunar valves closing after the pressure has built in the aorta and pulmonary trunk and the cusps fill, closing the semilunar valves during ventricular diastole
how blood moves from the atria to the ventricles
after contraction, 75% of the blood falls into the ventricles after which the atria contract slightly to pump the rest into the ventricles - atrial systole
what causes a murmur
the turbulent back flow of blood through a valve that does not close tightly
term for the contractile phase of the cardiac cycle
systole
term for the relaxation phase of the cardiac cycle
diastole
definition of the cardiac cycle
the series of pressure and volume changes in the heart during one heartbeat
ventricular filling
during mid to late ventricular diastole - AV valves open, SL valves closed and blood flow passively from atria to ventricles; end of ventricular diastole the atria contract (atrial systole) and push the last of the blood into the ventricles
phase in the cardiac cycle during which blood is pumped into the pulmonary trunk and aorta
ventricular systole - the atria relax (atrial diastole) and the ventricles contract (ventricular systole), closing the AV vlaves and opening the SL valves
what causes the SL valves to close and the AV valves to open
isovolumetric relaxation - during early ventricular diastole the ventricular pressure drops
cardiac output
the amount of blood pumped out of the ventricle per minute
how cardiac output is calculated
the product of stroke volume and heart rate
equation for cardiac output
CO = SV x HR