Upgrade to remove ads
Terms in this set (128)
3 components of the circulatory system
-heart serves as a pump that established the pressure gradient need for blood flow to tissues
-blood vessels are passages through which blood is distributed from heart to all parts of the body back to the heart
-blood is the medium in which materials being transported are dissolved or suspended
what is pulmonary circulation
closed loop of vessels that carry blood between the heart and the lungs
what is systemic circulation
the circuit of vessels that carry blood between the heart and other body systems
what is the major systemic artery?
carries blood from the heart to the lungs
carries blood fro the lungs to the heart
carries blood from the heart to body tissues
carries blood from body tissues to the heart
mean pressure of veins, artier, capillaries, and arterioles in order of highest of lowest
arteries, arterioles, capillaries, veins and venules
arteries are ___ reservoirs while veins are ___ reservoirs
the heart is what type of pump?
how many chambers in heart? what are they?
4; 2 atria that pump blood to 2 ventricles
what do arteries and veins do?
arteries carry blood form ventricles to tissue and veins carry blood from tissues to the atria
what is the septum?
muscular structure that prevents mixture of blood fro the 2 sides of the heart
what veins return blood from the body to the right atrium?
superior and inferior vena cava. superior bring back blood from the head and upper limbs while the inferior vena cava bring blood back form the trunk and legs
thickness of ventricular walls
left ventricular wall is thicker
blood flow through the heart
deoxygenated blood from the body is collected and carried through the superior and inferior vena cava. its brought to the right atrium which pumps the blood to the right ventricle, then through the 2 pulmonary arteries to the lungs. oxygen is added to this blood and CO2 is striped. the left and right pulmonary veins then carry the oxygenated blood from the lungs to the left atrium, where it pumps the blood to the ventricles who i turn pump the blood through the aorta to the body
systemic veins and arteries
systemic veins= vena cava
systemic artery= aorta
stroke volume of left and right side of the heart
both sides pump equal amounts of blood
BP and resistance of systemic and pulmonary circulation
pulmonary circulation is a low resistance and low pressure system while the systemic circulation is a high pressure and high resistance system
which side of the heart works harder?
what are AV valves
atrioventricular valves are positioned between atria and the ventricles. they prevent back flow of blood from the ventricles to the atria.
what is the right AV valve? left AV valve?
right AV valve= tricuspid valve
left AV valve= mitral or bicuspid valve
what happens when atrial pressure exceeds ventricular pressure?
what is the chordae tendinae? what is its purpose?
its the fibrous chords at the ends of the AV valves what help keep the valves from everting (opening in the opposite direction to allow back flow of blood)
what do the papillary muscles contribute to in the heart?
they are protrusions of the ventricular wall that connect to the chordae tendinae. they contract when the ventricles contract to pull on the chordae tendinae to keep closed AV valves in position
what are the semilunar valves? where are they located?
they are the aortic and pulmonary SL valves. they are located where the aortic and pulmonary arteries leave the ventricles
how are the SL valves kept from everting?
from their anatomic structure and position of the cusps
what are there no valves between the atria and veins?
because atrial pressure is not much higher than venous pressure. also because where the vena cava enter the right atria are partially compressed during atrial contraction
layers of the heart
-epicardium is the thin external layer made of connective tissue and serosa
-myocardium is the middle layer that makes up the bulk of the heart. its composed of cardiac muscle
-endothelium is the thing internal layer that is made of epithelial tissue
what do cardiac muscle cells need to support their ongoing, rhythmic, contractile activity?
abundance of energy-generating mitochondria and a constant supply of oxygen rich blood-> one capillary for each myocardial fiber
what connect the cardiac muscle fibers?
membrane junctions in intercalated discs
desmosomes and gap junctions
what are desmosomes
mechanically holds the cells together. are abundant in tissues susceptible to mechanical stress
what are gap junctions
areas of low electrical resistance that allow the spread of APs from one cardiac cell to another
group of interconnected muscles cells that function electrically and mechanically as a unit
what encloses the heart?
what makes up the pericardial sac
a thick fibrous tissue that anchors the heart in the chest and a secretary lining that produced pericardial fluid to prevent friction when the heart beats
what is it called when the heart contacts rhythmically by itself?
specialized types of cardiac muscle cells
contractile and autorhythmic
contractile cardiac cells
99% if cardiac muscle cells. do the mechanical work of pumping and don't initiate their own APs
autorhythmic cardiac cells
do not contract, but initiate and conduct APs responsible for contacting working cells
location of autorhythmic cells
SA node, AV node, purkinje fibers, bundle of his
what is the SA node
its the pacemaker of the heart. located in the right atrium near the opening of the SVC
where is the AV node located?
at the base of the right atrium near the septum
what is the bundle of His? where is it located?
it divides to form left and right branches that travel down the septum and up along outer walls of atrium. it originates at the AV node and enters the inter ventricular septum
what are purkinje fibers?
smal fibers that extend from bindle of his and spread through ventricular myocardium
where is the only point of electrical contact between the left and right heart chambers?
when impulse travels from atria into ventricles AV node
explain how electrical activity spreads throughout the heart
impulse originates at SA node and travels to right and left atria. from right atria it travels through the AV node where it is slowed down to allow ventricular filling. then to the inter ventricular septum down the bundle of his. the impulse spreads throughout myocardium by the purkinje fibers. then cells spread impulse to other cells via gap junctions
what is pacemaker potential
its the autorhythmic cell's membrane slow drift to threshold
ion changes that are important to pacemaker potential initiation
increased influx of Na, reduced passive efflux of K, and increased influx of Ca
when do voltage gated Na channels open in pacemaker cells?
when the membrane becomes more negative and hyperpolarizes
what are voltage gated Na channels in pacemaker cells called
permeability to K is ____ between APs in pacemaker cells
what causes the diminished efflux of K during APs in pacemaker cells?
the slow closure of K channels at negative potentials
when does Ca entry occur in pacemaker potentials?
-the transient Ca channels open when the funny channels close before the membrane reaches threshold. this brief influx further depolarizes the membrane, bringing it to threshold. the transient channels close
-once threshold is reached, long-lasting Ca channels open allowing large influx of Ca
whats different about the rising phase of pacemaker cells from nerve and skeletal muscle cells?
the rising phase of pacemaker cells is due to Ca influx rather than Na influx.
rising phase of pacemaker APs is due to...
Ca influx through long-lasting channels
falling phase of pacemaker cell APs is due to...
K efflux coupled with the closing of L-type Ca channels
what is the slow depolarization to threshold of pacemaker cells due to?
slow closure of voltage gated K channels
autorhythmic cells depolarize and generate APs at ____ rates
the heart cells with the fastest rate of AP initiation are localized where?
rate of autorhythmicity of the SA node
70-80 APs per minute
how does 80% of ventricular filling occur
during cardiac relaxation when the AV valves are open and venous blood enters the atria and flows directly to the ventricles
which fibrillation is worse
what is fibrillation
random and uncoordinated excitation and contraction of cardiac cells
conduction pathway from SA node to the right and left atria-> both atria depolarize and contract simultaneously
conduction pathway from SA node to AV node
membrane of pacemaker cells vs contractile cells
membrane of contractile cells remain at rest until excited by electrical activity
what keeps contractile cell membrane at resting potential?
especially leaky K channels--> efflux
action potential initiation in contractile cells
1. influx of Na through voltage gated channels causes depolarization. voltage gated channels close at peak potential
2. transient K channels open and allow fast efflux of K which causes a small repolarization in the membrane
3. plateau phase caused by slow long-lasting Ca channels opening and decrease in K permeability. the Ca is mostly responsible for the plateau, but closure of the transient and leaky K channels prevents rapid repolarization and prolongs plateau phase
4. falling phase is due to inactivation of Ca channels and delayed activation of ordinary K channels. reduced influx of Ca and increased efflux of K brings membrane back to resting potential
what is primarily responsible for the plateau phase?
slow influx of Ca through long lasting channels
where in contractile cells are L type Ca channels primarily located?
in the T tubules
Ca induced Ca release
when L type channels open to allow influx of Ca, it triggers the opening of ryanodine Ca channels in adjacent sarcoplasmic reticulum
what does Ca induced Ca release lead to?
cross bridge cycling and contraction
refractory period of skeletal muscles vs cardiac
skeletal muscle cells have a shorter refractory period
relationship between the action potential and refractory period of contractile cardiac cells
the duration are about the same
what does an EKG record?
electric activity that's present in body fluids from the cardiac impulse that reaches the body's surface
EKG record represents...
the sum of electrical activity in all cardiac cells
represents atrial depolarization
represents ventricular depolarization
represents ventricular repolarization
AV nodal delay
time where ventricles are contracting and emptying
time where atria and ventricles are relaxed and passive filling of ventricles happens
rapid heart rate of more than 100 BPM
slow heart rate of less than 60 BPM
tachycardia and bradycardia are abnormalities in ___
what is EKG rhythm?
regularity or spacing of EKG waves
what is arrhythmia
any variation from normal rhythm and sequence of excitation of the heart
arrhythmia can result from...
ectopi foci, alterations in SA node activity, or interference with conduction
what is ectopic foci
a group of excitable cells that causes a premature heartbeat
what can be used in an EKG to determine heart rate
there distance between two consecutive QRS complexes
whats atrial flutter
rapid but regular sequence of atrial depolarizations. AV node can't keep up. 2:1 or 3:1 rhythm of atrial impulses to ventricles
whats atrial fibrillation
rapid, irregular, uncoordinated depolarizations of the atria with no definite P wave
ventricular contractions are uncoordinated and chaotic
what are cardiac myopathies
damage of the heart muscle
inadequate delivery of oxygenated blood to heart tissue
death of cardiac muscle cells
acute myocardial infarction (heart attack)
occurs when blood vessels supplying the heart are blocked or ruptured
volume of blood ejected by each ventricle each minute
heart rate is primarily determined by what?
autonomic influences of the SA node
what is the parasympathetic nerve to the heart
what nerves supply the atrium?
parasympathetic and sympatetic nerves
which nerves richly innervate the ventricles?
what intrinsic and extrinsic factors determine stroke volume?
intrinsic= extent of venous return (influences muscle stretch)
extrinsic= sympathetic activity
extrinsic factors that influence HR
sympathetic and parasympathetic NS
increased ___ result sin increased stroke volume
end diastolic volume
what does intrinsic control of stroke volume depend on?
length tension relationship of cardiac muscle
increasing cardiac fiber length does what?
increases contractile strength
frank starling law of the heart
the heart pumps out during systole the volume of blood returned to it during diastole; increased venous return increases stroke volume
parasympathetic and sympathetic stimulation are ___ regulators
the greater the end diastolic volume, the greater the
force of contraction
the heart receives most of its own blood supply through...
coronary circulation during diastole
what happens to coronary vessels during systole?
they are compressed
coronary artery disease
pathological changes to the inner walls of coronary arteries that diminish blood flow
a progressive degenerative disease that leads to gradual blocking of affected vessels --> plaque forms beneath vessel lining within arterial walls
CAD can cause myocardial ischemia and a heart attack by which 3 mechanisms
-vascular spasm is an abnormal spastic contraction that narrow coronary vessels
-formation of atherosclerotic plaque
-thromboembolism is the formation of a thrombus and then an embolus
what is thrombus? embolus?
a thrombus is a blood clot stuck to the lining of a blood vessel. an embolus is a freely floating blood clot
chronotropic vs inotropic
chronotropic control rate and inotropic control force
stroke volume is controlled by ____ regulators
ventricular pressure vs atrial pressure when heart is relaxed
atrial pressure is greater
what happens in early diastole
-ventricle muscle relaxes and ventricular pressure decreases and aortic valve closes
-brief period where all valves close because vent pressure exceeds atrial pressure. waits for it to decrease
what happens in isovolumetric relaxation
after ventricular systole when aortic valve closes, AV valve does not open because ventricular pressure still exceeds atrial pressure. all valves are closed and fiber length and blood volume don't change. AV valve opens when ventricular pressure decreases
what happens in mid-late diastole
atria and ventricle are relaxed. atrial pressure exceeds ventricular pressure so AV valve is open to allow passive filling of ventricles. atrial pressure then exceeds ventricular pressure. aortic valve is closed and ventricular pressure increases
____ depolarization and ___ repolarization occur simultaneously. what does this mean?
ventricular depolarization and atrial repolarization. atria are in diastole while ventricles are in systole
what happens at the end of diastole
SA node initiates AP and atria deplarizes and contracts. active filling adds to blood in ventricle. the blood in the ventricle here is known as EDV
what happens in systole
-ventricular pressure exceeds atrial pressure. AV valve closes and the aortic valve remains shut to allow build up of ventricular pressure
-once ventricular pressure increases more aortic valve opens so blood is ejected to the aorta.
-aortic pressure increases as ventricular pressure decreases.
THIS SET IS OFTEN IN FOLDERS WITH...
Reproductive system review guide
Topic 4 Lymphatic System Part 2
Digestive System Review Guide
physio ch 1+2 titles
YOU MIGHT ALSO LIKE...
A&P lecture exam 2 review
Ch 11: Cardiovascular System Topic Guide
Animal Physiology circulatory system
OTHER SETS BY THIS CREATOR
history exam #2
ankle and lower leg
OTHER QUIZLET SETS
Bio212 Exam 3: Respiratory Notes
Bio 20 Circulation/immunity
Chapter 18 Anatomy of the Blood Vessels