Exam 3 Human Phys Parrish Mizzou

Cardiac

get blood to tissues

what is the major role of the cardiovascular system

nutrients, gases, electrolytes

what are the three most important things transported by the cardiovascular system

body is too big

why can’t the human body use diffusion to transport nutrients

transportation, regulation, protection

what three tasks are accomplished by the cardiovascular system

blood, heart, vessels

what are the three major components of the cardiovascular system

lymphatic system and respiratory system

what are the two body systems that works with the cardiovascular system directly

5 liters

what is the average adult blood volume

arterial blood

what kind of blood leaves the heart

venous blood

what kind of blood enters the heart

formed elements

45% of blood

plasma

55% of blood

water, dissolved solutes, proteins

what three components make up blood plasma

albumin

plasma protein that creates osmotic pressure to help draw water from tissues back into capillaries to maintain blood volume and pressure

fibrionogen

helps in clotting

fibrin

active form of fibrinogen

thrombin

what activates fibrinogen into fibrin

plasminogen

what breaks down a fibrin polymer into fibrin fragements

red blood cells

what is the formed element in the blood

carry oxygen

what is the main purpose of RBC

nuclei and mitochondria

what organelles do RBC lack

hemoglobin

molecule in RBC that aids in O2 transport

280M

how many hemoglobin molecules in each RBC

anemia

abnormally low RBC count or low hemoglobin content within RBC which reduces O2 carrying capacity

hematocrit

% of total blood volume that is RBC, used as a measure of oxygen carrying capacity of blood

right atrium

receives deoxygenated blood from the body

left atrium

receives oxygenated blood from the lungs

right ventricle

pumps deoxygenated blood to the lungs

left ventricle

pumps oxygenated blood to the body

fibrous skeleton

separates atria from ventricles. the atria therefore work as one unit, while the ventricles work as a spearate unit. forms the annuli fibrosi rings, which hold in heart valves

pulmonary and systemic

what are the two circulations

artery

away from heart

vein

towards heart

AV valve

located between the atria and the ventricles

tricuspid valve

AV valve on right side

bicuspid

AV valve on left side

semilunar valves

located between the ventricles and arteries leaving the heart

pulmonic 

semilunar valve between right ventricle and pulmonary artery

aortic

semilunar valve between left ventricle and aorta

pressure higher on leading side

what is a requirement for the opening of a valve

pressure is lower on the leading side

what is required for a valve to close

one way flow

what does valve opening requirements ensure

lub

heart sound produced by the closing of the left and right AV valves. beginning of ventricular systole/end of ventricular diastole

dub

closing of aortic pulmonic valves; occurs at the end of ventricular systole/beginning of diastole

systole

contraction of ventricular heart muscle

diastole

relaxation of ventricular heart muscle

ventricular filling, isovolumetric contraction, ventricular ejection, isovolumetric relaxation

what are the 4 phases of the cardiac cycle

ventricular filling

filling of ventricle, relaxation/diastole, very low pressure

isovolumetric contraction

start of contraction, no ejection, systole, developing pressure

ventricular ejection

contraction, high pressure

isovolumetric relaxation

start of relaxation/diastole, falling pressure, no volume change

stroke volume

what is represented by the width of the PV loop

stroke volume

amount of blood ejected per beat

valve opening/closing

what do the dots on the PV loop represent

end diastolic volume

total volume of blood in the ventricles at the end of filling (diastole)

end systolic volume

the amount of blood left in the ventricle after ejection (systole)

gap junctions

what interconnects cardiac muscle cells

separate

do ventricles and atria contract as separate or connected parts of cardiac muscle

contractile cells

cardiac muscle cells (myocytes), striated myofibers organized into sarcomeres, force production leads to an increase in pressure. 

pacemaker cells

initiate action potential, smaller and fewer contractile fibers, no organized sarcomeres

sinoatrial (SA) node

initiates electrical signal at right atrium

AV node

initiates electrical signal between atria and ventricles

bundle of his

help electrical signal travel down ventricle

purkinje fibers

help continue electrical signals past bundle of his and into walls of ventricles

slow, spontaneous depolarization

what is the main structure difference of pacemaker action potentials

-40 mV

what is the voltage required to open voltage gated Ca2+ channels in pacemaker cells to trigger an action potential

Ca2+

what ion channel causes pacemaker action potentials

K+

what ion causes repolarization for pacemaker action potentials

Na+

what channel is triggered by hyperpolarization in pacemaker potentials

rate

what can be modulated about pacemaker potentials

speeds HR, increase Na+

what effect does sympathetic release of epi/norepi have on cardiovascular system, how does this effect happen

slows HR, increase K+

what effect does parasympathetic release of Ach have on cardiovascular system, how does this effect happen

slope

what is changed on a pacemaker potential due to autonomic control of HR

negative

what kind of resting potential does cardiac muscle cells have

plateau

what is the noticable difference in cardiac myocyte action potentials

slow Ca2+ influx

what is the cause of the plateau in cardiac myocyte action potentials

Na+

what ion causes the increase in potential for cardiac myocytes

K+

what ion causes repolarization for cardiac myocytes

twitch contraction, longer refractory period

what physiological effect does the plateau have on cardiac contraction

longer, last almost as long as entire muscle twitch

how is the refractory periods different in cardiac muscle cell

no

in a normal heart, can tetanus be reached

rapid twitch

what happens when there are multiple action potentials in cardiac muscles

Ca from extracellular leads to Ca release from SR

how does cardiac muscle get Ca for contraction

both

does SA node only activate right atrium or both right and left atrium

slow

does action potentials slow or speed up when it reaches the AV node

EKG

records electrical activity of heart by picking up the movement of ions in body tissues in response to electrical spread. does not record action potentials, contraction , or relaxation, just electrical activity

P wave

atrial depolarization on EKG

QRS complex

ventricle depolarization in EKG

T wave

ventricular repolarization

QRS covers it

why can’t you see atrial repolarization on EKG

aorta - arteries - arterioles - capillaries - venules - veins - vena cava

what is the pathway of vasculature starting after oxygenated blood leaves heart and ending right before deoxygenated blood enters heart 

arteries

large diameter, elastic, pressure reservoir that maintains blood pressure/flow during ventricular relaxation

capillaries

where does exchange between blood and cells take place

veins

volume reservoir, stretchy walls, some smooth muscle cells, one way valves

just before ejection

when is aortic pressure lowest

just after ejection

when is aortic pressure highest

arterioles

contraction or relaxation here (increase or decrease in diameter) regulates blood flow and pressure to cap beds, steep pressure drop

2/3

what ratio of blood is in veins

more blood flow to heart (higher venous return, increase ventricle filling)

what is the impact of sympathetic stimulation on veins (increase contraction)

hydrostatic or osmotic pressure gradients

what allows for larger solutes and proteins to move in and out of capillaries by bulk flow

filtration

fluid movement out of capillaries caused by blood pressure gradient