Cardiac Output & Venous Return Terms | Medicine Study Set

weight/height^2

body mass index formula

metabolism increases

cardiac output increases

what happens to metabolism and cardiac output in the case of hyperthyroidism

heart rate x stroke volume

cardiac output formula

heartbeat originates from the sinus node with a regular rhythm

what does normal sinus rhythm mean?

how often the sinus node spontaneously depolarizes

sympathetic nervous system

parasympathetic nervous system

normal sinus rhythm is determined by....

parasympathetic nervous system

at rest the greatest influence on heart rate comes from the...

it increases

if you cut the nerves to the sinus node what happens to heart rate?

bradycardia

defined as a heart rate of less than 60 beats a minute

tachycardia

heart rate of greater than 100 beats per minute

40-60 bpm

heart rate during av junctional rhythm

ventricular rhythm

when the heartbeat originates in the ventricles

idioventricular rhythm

_______ is known as slow heart rate of about ______ originating in the purkinje fibers.

ventricular tachycardia

a very rapid heartbeat that begins within the ventricles

atrial fibrillation

chaotic electrical activity in the atria. action potentials transmitted to the av node frequently. leads to fast irregular heart beat

sympathetic stimulation

sinus tachycardia is sometimes caused by ______

parasympathetic stimulation

sinus bradycardia can sometimes be caused by ____

AV junctional rhythm

during _____ P waves are inverted and may occur before, during, or after QRS

forward

backward

during av junctional rhythm the action potential will go _____ through the ventricles and _____ through the atria

wider QRS

slower heart rate

how are the heart rate and QRS and heart rate affected by idioventricular rhythm

Ventricular Tachycardia

heart rhythm with wide QRS and no visible P waves

ventricular tachycardia

heart rhythm where the ventricles are beating too fast and dont have time to fill appropriately

atrial fibrillation

heart rhythm with irregular and frequently fast

pressure difference/resistance

blood flow =

pressure difference/resistance

(peripheral venous pressure-central venous pressure/resistance)

venus return =

peripheral veins

peripheral venous pressure is derived in the ____

right atrium

central venous pressure is derived from the _____

-sympathetic stimulation (smooth muscle in the veins)

-increased blood volume

-skeletal muscle contraction (veins inside the muscles are squeezed)

peripheral venous pressure can be increased by...

longitudinaly

smooth muscle in the veins is arranged_____

increased

during inspiration venous return is ____, due to diaphragm being flexed.

decrease

inspiration will _____ central venous pressure by expanding the thoracic cavity.

compliance

change in volume over change in pressure =

increase

during diastole, blood entering the left ventricle will cause left ventricular pressure to ____

higher

lower

decreased compliance results in ____ pressure and _____ volume

higher

lower

increased compliance results in _____ volume and ____ pressure

aortic regurgitation

during _____, blood leaks backward into the left ventricle during diastole

increasing compliance (takes in more blood, pumps out more blood) which increases LV end diastolic volume

the left ventricle responds to aortic regurgitation by...

aortic stenosis

____ refers to reduction in the valve area of the aorta

increased resistance to LV outflow (afterload) causes LV hypertrophy (walls thicken) which decreases LV compliance.

aortic stenosis results in...

mitral stenosis

increased inflow resistance for the LV is referred to as ____

decreased filling of the left ventricle

mitral stenosis leads to...

an increase of leftover blood in the left ventricle

decrease in ventricular contractility results in...

more time for filling left ventricle

decreased heart rate allows for...

left ventricle must spend more energy developing pressure and allows less energy to eject blood, leaving more blood remaining in left ventricle

increased afterload in the left ventricle causes....

increases left ventricle end diastolic volume

increase in atrial stroke volume...

down

if afterload goes up, stroke volume goes ____

up

if stroke volume goes up, preload goes ___

up

if contractility goes up, stroke volume goes ____