MMED 8115 exam 3

What is the circulation system composed of?

heart, blood vessels and blood

What are the circulatory systems of blood?

systemic and pulmonary

What does the systemic circulation carry blood between?

heart and organ systems

What/where does the systemic circulation carry in the blood in terms of CO2 and O2?

moves O2 to tissues and CO2 back to heart

Which circulatory circulation system maintains appropriate blood pressure?

systemic circulation

Where does the pulmonary circulation carry blood?

between heart and lungs

what is the pulmonary circulation relation to O2/CO2 in the blood?

moves O2 from inhaled air into blood and removes CO2 from blood and releases it to the atmosphere

Roles of circulatory system

transports O2, CO2, nutrients, waste products, hormones, excess heat; and regulates blood pressure

how many chambers is the heart?

four

How does the two-sided pump in the heart function?

in parallel

Direction of blood through the heart

deoxyngenated blood from the body enters the right atrium through the vena cava, then moves to the right ventricle, then gets pump to the lungs in the pulmonary artery to exchange CO2 for O2, then moves through the pulmonary vein to the left atrium, then moves to the left ventricle, then moves the oxygenated blood to the body through the aorta

What is the black pointing to?

pulmonary artery

What is the dark blue pointing to?

deoxygenated blood from the body

What is the dark green pointing to?

vena cava

What is the light green box?

right atrium

What is the pink box?

right ventricle

What is the dark purple box?

lungs

Ehat is the light purple box?

left atrium

What is the light blue box?

left ventricle

What is the brown pointing to?

Atrial septum

What is the dark pink pointing to?

venticular septum

What is the grey pointing to?

pulmonary vein

What is the red indicating?

oxygenated blood to the body

What is the yellow pointing to?

aorta

What heart chambers does deoxygenated blood pass through?

right atrium and right ventricle

What heart chambers does the oxygenated blood pass through?

left atrium and left atrium

arteries

carries blood to other organs

veins

carries blood to heart from other organs

base of the heart

top part of the heart above left and right atrium

Superor vena cava

returns blood from head and upper limbs

right pulmonary veins

returns blood from right lung

pulmonary semiluar valve

valve between right ventricle and pulmonary arteries

right atrioventricular valve

valve between right atrium and right ventricle

inferior vena cava

returns blood from trunk and legs

left pulmonary veins

returns blood from left lung

aortic semilunar valve

valve between left ventricle and aorta

left atrioventicular valve

valve between left atrium and left ventricle

Ventricular septum

separates right and left ventricles

apex of heart

bottom of heart (below the ventricles)

full name of right trioventricular valve

right atrioventricular ticuspid valve

full name of left atrioventricular valve

left atrioventricular mitral/bicuspid valve

Which ventricular muscles are thicker/stronger?

left

Why are the left ventricular mucsles thicker/stronger?

left pumps blood out into the arota against a much higher systemic blood pressure and the right pumps blood to pulmonary circulation with a lowr pressure

pericarditis

inflamation/viral

cardiac tamponade

fluid in cavity/trama

What is the yellow box pointing to?

fibrous pericardium

What is the red box pointing to?

parietal pericardium

What is the dark pink/red box pointing to?

pericardial cavity

What is the grey box pointing to?

visceral pericardium

What is the green box pointing to?

pericardium

What is the blue box pointing to?

mycoardium

What is the purple box pointing to?

endocardium

What is the pericardium of the heart?

the heart sac

myocardium

cardiac muslce layer/tissue

myocardial infaraction

heart attack; happens when a part of the myocardium fails to receive enough oxygen

situs inversus totalis

left-right inverted organs

Where is the heart beat felt the most by hand (point of maximal impulse (PMI))?

near apex, on the mid-clavicular line

Which direction do pressure-operated valves allow blood flow?

only one direction; from chambers of higher pressure to thos of lower pressure

What happens to atrioventricular valves when the ventricles relax ?

blood enters the atria, pushing the atrioventricular valve cusps down ino the ventricles, opening the valves

What happens to atrioventricular valves when the ventricles contract?

blood presses up against the atrioventricular valve cusp, forcing the valves closed. Contraction of the papillary muscles tightens the chordae tendineae, preventing the valve cusps from being pushed into the atria

What is in the purple box?

atrioventricular valve cusp

What is the green box?

chordae tendineae

What is the brown box?

pulpillary muscle

Does the chordae tendineae pull the valve open?

no, they serve as an anchor to prevent eversion of valve during ventricular contraction

What happens to semilunar valves when ventriculars contract?

blood presses up against the semilunar valve cusps, forcing the valves open and allowing blood to flow into the aorta and pulmonary artery

What happens to the semilunar valves when the ventricles to relax?

the blood in the aorta and pulmonary artery presses down against the valve cusps, forcing them to close

Properties of “cardiac skeleton”

composed of rings of dense connective tissue around 4 valves; forms a single spatial plane that contains 4 valves

roles of “cardiac skeleton”

anchors valves; anchors atrial muscles above and ventricular muscles below; acts as electrical insulator between atria and ventricles

what is the electrical role of “cardiac skeleton” important for?

controlling the timing and direction of cardiac muscle contractions

Echocardiogram

real-time view of heart, using ultrasound

Heart valve diseases

stenosis, regurgitation, atresia

stenosis (heart valve disease)

the valve flaps/leaflets become thick or stiff and possibly fuse together; results in a narrowed valve opening and reduced blood flow through the valve

regurgitation (heart valve disease)

the valve flaps don’t close properly, causing blood to leak backward in heart; this commonly occurs due to valve flaps bulging back (prolapse)

prolapse

valve flaps bulging back

Atresia (heart valve disease)

the valve isn’t formed and a solid sheet of tissue blocks the blood flow between the heart chambers

directional waves in the heart involve what?

electrical excited (surface) and muslce contraction

Directional waves of electrical ecitation and muscle contraction order

from top of atrium to its bottom; intermettent period (delay); from the bottom of the ventricle to its top

Which heart chambers contract simultaneously?

left and right atria contract simultaneously; left and right ventricles contract simultaneously

Cardiac functions made possible by directional waves of electrical excitation and muscle contraction

atria push blood downward to ventricles; delay is necessary to fill ventricles with blood; ventricles push the blood upeard to either pulmonary artery or aorta

What do irregular electrical activities lead to?

abnormal contractions; in extreme cases, ventricles twitch uselessly, leading to sudden cardiac death

ventricular fibrillation

ventricles twitching uselessly

Intercalated discs

specialized structures that allow cardiac muscle cells to be joined end-to-end

What are the two main structures of intercalated discs?

desmosomes and gap junctions

desmosomes

a type of adherence junction which holds the cells together

gap junctions

areas of low electrical resistance that allow action potentials to spread from cell to cell

functional syncytium

if an action potential is initiated in any cell, it will spread throughout the connected muslce cells

initiation of contraction in cardiac muscle

myogenic/pacemaker potentials (has the ability to initiate its own muscle contractions)

What happens once electrical activity is initiated?

will spread throughout the myocardium; but cardiac skeleton electrically separates artia and ventricles and creates two subgroups of syncytia

what of the two subgroups of syncytia in the heart?

atrial and ventricular; which contract sequentially with a delay

What is the atrio-ventricular node (AV node)?

a single, narrow connecting path between atrial and ventricular syncytia

What does the AV node allow for?

atrial excitation conduction to ventricles with a delay

What is the cardiac conduction system composed of?

cardiac pacemakers

cardiac pacemakers

specialized myocardial cells that are devoted to generation and conduction of auto-rhythmic, pacemaker potentials

Where are pacemaker potentials initiated and where does it spread to?

initiated in the SA node in the right atrium and spreads to the left atrium

What is normally the only way for a depolarization wave to get to the atria to the ventricles?

the AV node (due to the insulating cardiac skeleton)

AV nodal delay

conduction through AV node is slow, which creates a delay between atria and ventricles

wave of depolarization from the AV node

does not spread uniformly over the venricular myocardium

wave of depolarization from the AV nodes pathway

spreads down the ventricular septum through the Bundle of His, left and right bundle branches; then spreads from apex upward through the Purkinje fibers

what do Purkinje fibers enable?

ventricular contraction beginning primarily at the apex and pushing the blood upward toward pulmonary and arotic valves

what is the brown box?

SA node