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12. Cardiovascular System
N/A
207
Physiology
Undergraduate 2
10/16/2012

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Cards

Term
What are the three main components of the cardiovascular system?
Definition
  • blood
  • blood vessels
  • heart
Term
What are the three types of blood vessels?
Definition
areteries, veins, and capillaries
Term
What are the three types of circulation?
Definition
  • pulmonary circulation
  • systemic circulation
  • lymphatic circulation (system)
Term
What is pulmonary circulation?
Definition
circulation that goes from the heart to the lungs 
Term
What is systemic circulation?
Definition
circulation that goes from the heart to the rest of the body
Term
What three systems is the lymphatic system involved with?
Definition
cardiovascular, immune, and digestive systems
Term
What is systolic pressure (mm Hg)?
Definition
the highest arterial blood pressure reached during any given ventricular cycle
Term
What is diastolic pressure (mm Hg)?
Definition
the lowest arterial blood pressure reached during any given ventricular cycle
Term
What is venous pressure (mm Hg)?
Definition
the pressure exerted on the walls of the veins by the circulating blood
Term
What is packed cell volume (%)?
Definition
the ratio of the volume occupied by packed red blood cells to the volume of the whole blood as measured by a hematocrit
Term
What is stroke volume (mL)?
Definition
the volume of blood pumped out of one ventricle of the heart in a single beat
Term
What other three things are measured with regards to the cardiovascular system?
Definition
  • heart rate (per min)
  • leukocytes (per micro liter)
  • erythrocytes (per micro liter)
Term
What are the four main structures of the heart?
Definition
  • atrium
  • ventricle
  • septum
  • myocardium
Term
The sinoatrial (SA) node is also known as the _________ of the heart.
Definition
pacemaker
Term
What is the sinoatrial node?
Definition
a small specialized region in the right atrial wall in reptiles, birds, and mammals
Term
What is the atrioventricular (AV) node?
Definition
a small bundle of specialized cardiac muscle cells located at the base of the right atrium near the septum, just above the junction of the atria and ventricles
Term
What is myogenic contraction?
Definition
myocytes contraction that originates from a property of the myocyte itself (ex: the contraction is initiated by the cell itself, not an outside occurance or stimulus such as a nerve innervation
Term
What type of muscle in the body exhibits myogenic contraction?
Definition
the heart muscle
Term
What is neurogenic contraction?
Definition
muscle contraction that originates from an external neural stimulus
Term
5
Definition
Term
How did vertebrate systemic hearts evolve?
Definition
they evolved from a two-chambered heart into four-chambered heart
Term
Avian and mammalian hearts are _____ pumps.
Definition
dual
Term
What is the sequence of blood circulation starting with the vena cava?
Definition
  • vena cava, right atrium, right ventricle, pulmonary artery, lungs, pulmonary vein, left atrium, left ventricle, aorta, systemic circulation
Term
What are the four main valves in the heart?
Definition
  • tricuspid valve
  • pulmonary valve
  • aortic valve
  • mitral valve
Term
Which valve is the right atrioventricular valve?
Definition
the tricuspid valve
Term
Which valve is the left atrioventricular valve?
Definition
mitral valve
Term
Why is the wall of the right ventricle so much thinner than the wall of the left ventricle?
Definition
because the left ventricle has to pump blood all throughout the body while the right ventricle only has to pump it to the lungs
Term
What is the purpose of heart valves?
Definition
they ensure that blood flows in the proper direction through the heart
Term
When pressure behind the valve is greater, it (closes/opens).
Definition
opens
Term
When pressure is greater infront of the valve, it (closes/opens). Why?
Definition
closes; because valves are on;y one-way so they do not open in the opposite direction
Term
What is the purpose of atrioventricular valves?
Definition
they prevent backflow of the blood from the ventricles to the atria during ventricular systole (contraction)
Term
What are the two atrioventricular valves?
Definition
tricuspid valve and mitral valve
Term
Where is the tricuspid valve located?
Definition
between the right atrium and ventricle
Term
Where is the mitral valve located?
Definition
between the left ventricle and atrium
Term
What is the purpose of the semilunar valves?
Definition
to prevent backflow of blood from the arteries (pulmonary artery and aorta) to the ventriclesduring ventricular diastole
Term
What are the two semilunar valves?
Definition
aortic valve and pulmonary valve
Term
Where is the aortic valve located?
Definition
between the left ventricle and the aorta
Term
Where is the pulmonary valve located?
Definition
between the right ventricle and the pulmonary artery
Term
What type of tissue are valves made of? How does this affect the way they work?
Definition
connective tissue (not cardiac muscle tissue); this means that they open and close passively in response to changes in pressure
Term
What is ventricular systole?
Definition
contraction
Term
What is ventricular diastole?
Definition
relaxation
Term
Cardiac muscle is (unstriated/unstriated) and consists of __________ that is similar to _______ muscle.
Definition
striated, sarcomeres, skeletal
Term
How many nuclei does cardiac muscle contain?
Definition
more than one
Term
Cardiac muscle cells contain numerous ___________. They make up up to ___% of the cell volume.
Definition
mitochondria, 40
Term
Adjacent cells are joined end to end at structures called ________ that contain _________.
Definition
intercalated discs, desmosomes
Term
What is the function of intercalated discs and desmosomes?
Definition
they act like rivets and hold the cells tightly together where gap junctions permit action potentials to easily spread from one cardiac muscle cell to adjacent cells
Term
What are the two types of cardiac muscle cells?
Definition
contractile cells and autorythmic cells
Term
Most muscle cells in the heart are _______ cells.
Definition
contractile
Term
What is depolarization in contractile cells like?
Definition
it is very rapid and due to the inward diffusion of sodium
Term
What happens during repolarization of contractile cells?
Definition
  • it begins with a slow outward diffusion of potassium, but that is largely offset by the slow inward diffusion calcium
  • this means that repolarization begins with a plateau phase 
  • then potassium diffuses out much more rapidly as the calcium channels close, and the membrane potential quickly reaches the resting potential
Term
Autorythmic cells exhibit _______ potentials.
Definition
pacemaker
Term
What causes depolarization in autorythmic cells?
Definition
it is due to the inward diffusion of calcium, not sodium, as in nerve cells
Term
What happens during depolarization of autorythmic cells?
Definition
the slow calcium channels open and then depolarization quickly concludes when the fast calcium channels open 
Term
What causes repolarization of autorythmic cells?
Definition
the outward diffusion of potassium
Term
What parts of the heart are made up of autorythmic cells?
Definition
  • sinoatrial node
  • atrioventricular node
  • atrioventricular bundle
  • right and left bundle branches
  • purkinje fibers
Term
What is the antriventricular bundle sometimes called?
Definition
the bundle of His
Term
18
Definition
Term
Autorythmic cells don't have voltage gated ____ channels.
Definition
Na+
Term
In autorythmic cells, ____ permeability changes between action potential cycles.
Definition
K+
Term
19
Definition
Term
20
Definition
Term
The ____ node exhibits the fastest rate of autorythmicity. 
Definition
SA
Term
How does the heart ensure efficient pumping?
Definition
by coordinating the spread of cardiac excitation
Term
What must be complete before the onset of ventricular contraction?
Definition
atrial excitation and contraction
Term
The pair of _____ and pair of _____ should be functionall coordinated so that both members of the pair contract ___________.
Definition
atria, ventricles, simultaneously
Term
Electrical activity of autorythmic cells begins at the ________ and quickly spreads through ________.
Definition
SA node, both atria
Term
The electrical activity of autorythmic cells that starts as the SA node then travels through the heart's conducting system which includes moving from the _________ to the ________ to the ________ and then to the ________ through the ventricles.
Definition
AV node, AV bundle, bundle branches, purkinje fibers
Term
Different autorythmic cells have different _______.
Definition
rhythms
Term
24
Definition
Term
24
Definition
Term
24
Definition
Term
What part of the heart has the fastest rhythm? What does this result in?
Definition
SA node, which results in it setting the rate of contraction for the entire heart
Term
25
Definition
Term
The action potential of contractile cardiac muscle cells shows a charcateristic _______.
Definition
plateau
Term
What maintains the plateau in contractile cells?
Definition
activation of slow Ca2+ channels and marked decrease in K+ permeability 
Term
What happens during the rising phase of an action potential in contractile cells?
Definition
the membrane rapidly becomes reversed from -90mV to 30mV by an explosive increase in the Na+ permeability
Term
What causes the rapid falling phase of the action potential in contractile cells?
Definition
inactivation of the Ca2+ channels and activation of EAG K+ channels
Term
28
Definition
Term
During electrical activity of the contractile cells, what does Ca2+ entry from the ECF induce? What does this result in?
Definition
a much larger calcium release from the sarcoplasmic reticulum; results in a longer period of cardiac contraction
Term
How is tetanus of the cardiac muscle prevented?
Definition
a long refractory period
Term
31
Definition
Term
What does a long refractory period in the cardiac muscle mean?
Definition
it means that the muscle cannot be stimulated again until contraction is almost over and this makes summation impossible 
Term
Why is a refractory period in cardiac muscle considered to be an important protective mechanism?
Definition
because pumping requires alternate periods of contraction and relaxation; prolonged tetany would prove fatal
Term
In descending order, which four parts of the body recieve the most amount of blood?
Definition
  • digestive system
  • kidneys
  • skeletal muscle
  • brain
Term
What does cardiac output depend on?
Definition
heart rate and stroke volume
Term
What is the formula for cardiac output?
Definition
cardiac output (vol/min) = heart rate (beats/min) x stroke volume (vol/beat)
Term
What is heart rate primarily determined by?
Definition
  • antagonistic regulation of autonomic influences on the SA node
Term
What happens in parasympathetic control of the heart?
Definition
  • acetylcholine is released which binds to the muscarinic receptor at the SA and AV nodes which are coupled to the inhibitory G protein
Term
What does parasympathetic control of the heart cause?
Definition
  • decreased heart rate
  • decreased excitability of the AV node
  • shortens the action potential of atrial contractile cells
Term
What happens during sympathetic control of the heart?
Definition
  • the sympathetic nerve releases norepinephrine which binds to the beta-adrenalgic receptor coupled to stimulatory G protein which accelerates the cAMP pathway
Term
What does sympathetic control of the heart cause?
Definition
  • increased heart rate; reduces AV nodule delay
  • speeds up the spread of action potential
  • increases contractile strength of atrial and ventricle cells
Term
Where is the cardiovascular control center located? What does it control?
Definition
  • in the brain stem
  • it controls heart rate
Term
39
Definition
Term
What determines stroke volume?
Definition
the extent of venous return and by sympathetic activity
Term
What is intrinsic control?
Definition
the extent of venous return
Term
What is extrinsic control?
Definition
the extent of sympathetic stimulation
Term
An increased end-diastolic volume results in increased ____________.
Definition
stroke volume
Term
42
Definition
Term
What does blood flow through vessels depend on?
Definition
pressure gradient and vascular resistance
Term
How does pressure gradient affect blood flow?
Definition
the higher the pressure gradient, the larger the blood flow
Term
How does vascular resisstance affect blood flow?
Definition
the higher the resistance, the less blood flow
Term
Where is pressure gradient measured?
Definition
the heart
Term
Where is resistance measured?
Definition
blood vessels
Term
What three factors of the blod vessels affects resistance?
Definition
  • viscosity
  • vessel length
  • vessel diameter
Term
What is the main determinant of vascular resistance?
Definition
vessel diameter
Term
What is the formula for calculating blood flow?
Definition
F = change in pressure/ resistance
Term
As the difference in pressure between the two ends of the vessels increases, blood flow (increases/decreases).
Definition
increases
Term
45
Definition
Term
46
Definition
Term
What are the two main functions of arteries?
Definition
  • to serve as a rapid transit-passage pathway for blood from the heart to tissues
  • to act as a pressure reservoir to provide a driving force for blood when the heart is relaxing
Term
What are the two main arteries?
Definition
the pulmonary artery and the aorta
Term
What is arterial endothelial lining made up of?
Definition
smooth muscle and two connective tissues, collagen and elastin
Term
Arteries are analogous to a _______.
Definition
highway
Term
Arterioles are analogous to a ___________.
Definition
small highway
Term
Capillaries are analogous to _________.
Definition
side streets
Term
Veins are analogous to _________.
Definition
waste pathways
Term
What is Professor Han's favorite movie?
Definition
The Incredibles
Term
When the heart is contracting and emptying, what happens to the arteries?
Definition
they expand
Term
What happens when the heart is relaxing and filling?
Definition
the arteries contract
Term
51
Definition
Term
What causes the dicrotic notch in arterial blood pressure?
Definition
when the aortic valve closes, the pressure increases slightly, causing a temporary increase in blood pressure
Term
What is the main driving force for arterial blood flow?
Definition
mean arterial pressure
Term
What is the formula for mean arterial pressure?
Definition
mean arterial pressure = diastolic pressure + (1/3)(systolic pressure-diastolic pressure)
Term
If someone's blood pressure is 120/80, what is their systolic and diastolic pressure?
Definition

systolic: 120

diastolic: 80

Term
If someone's blood pressure is 120/80, what is their mean arterial pressure?
Definition
80 + (1/3)(120-80) = 93.333
Term
What is the function of arterioles?
Definition
they control blood distribution and are the major resistance vessels
Term
Why are arterioles considered to be the major resisatnce vessels?
Definition
they create more resistance in vessels that lead to parts of the body where they don't want to send blood
Term
What happens during vasoconstriction?
Definition
there is increased contraction of circular smooth muscle in the arteriolar wall, which leads to increased resistance and decreased flow through the vessel
Term
What happens during vasodilation?
Definition
there is decreased contraction of circular smooth muscle in the arteriolar wall which leads to decreased resistance and increased flow through the vessel
Term
What things can cause vasoconstriction?
Definition
  • increased myogenic activity
  • increased oxygen consumption
  • decreased CO2 and other metabolites 
  • endothelin
  • sympathetic stimulation
  • vasopressin, angiotensin II
  • cold
Term
What things can cause vasodilation?
Definition
  • decreased myogenic activity
  • decreased O2
  • increased Co2 and other metabolites
  • increased nitric oxide
  • decreased sympathetic stimulation
  • histamine release
  • heat
Term
56
Definition
Term
What is local (intrinsic) control of arteriolar radius important for?
Definition
determines the distribution of cardiac output
Term
_________ increases blood supply to meet metabolic demands.
Definition
vasodilation
Term
High resistance causes _____ flow.
Definition
no
Term
Moderate resistance causes _______ flow.
Definition
moderate
Term
Low resistance causes ____ flow.
Definition
high
Term
When going from rest to doing exercise, how much does the amount of blood flow to the brain change?
Definition
it doesn't change
Term
What local metabolic influences on the arteriolar radius help match blood flow with tissue needs?
Definition
  • decreased O2
  • increased CO2
  • increased acid (from increased CO2)
  • increased K+ (action potential)
  • increased osmolarity
  • adenosine release
Term
What is extrinsic sympathetic control of arteriolar radius most important for?
Definition
the regulation of arterial blood pressure
Term
What are the formulas for flow and pressure difference?
Definition
  • flow= difference in pressure/ rate
  • difference in pressure = flow x rate
Term
What is the main function of sympathetic stimulation in the cardiovascular system?
Definition
  • constricts blood vessesl to help maintain pressure
Term
How do norepinephrine and alpha adrenergic receptors interact?
Definition
Norepinephrine combines with an alpha adrenergic receptor, inducing vasoconstriction for assuring blood supply to the brain in the expense of other organs
Term
______ controls override sympathetic vasoconstriction and increasing blood supply.
Definition
local
Term
There is a lack of _______________ innervation to most arterioles.
Definition
parasympathetic
Term
How many large arterial branches are there?
Definition
several hundred
Term
How many arterioles are there?
Definition
half a million
Term
How many capillaries are there?
Definition
ten billion
Term
How many large veins are there?
Definition
several hundred
Term
How many aortas are there?
Definition
one
Term
How many vena cavas are there?
Definition
two
Term
What is the wall thickness of the aorta?
Definition
2mm (2,000 micrometers)
Term
What is the wall thickness of large arterial branches?
Definition
1 mm (1,000 micrometers)
Term
What is the wall thickness of arterioles?
Definition
20 micrometers
Term
What is the wall thickness of capillaries?
Definition
1 micrometer
Term
What is the wall thickness of large veins?
Definition
.5 mm (500 micrometers)
Term
What is the wall thickness of vena cava?
Definition
1.5 mm (1,500 miscrometers)
Term
Name all the different blood vessels from largest wall thickness to smallest wall thickness.
Definition
  • aorta
  • vena cava
  • large arterial branches
  • large veins
  • arterioles
  • capillaries
Term
Name all the blood vessels in order from largest internal radius to smallest.
Definition
  • vena cava
  • aorta
  • large veins
  • large arterial branches
  • arterioles
  • capillaries
Term
What is the function of the aorta and large arterial branches?
Definition
passageway from the heart to the tissues; serve as a pressure reservoir
Term
What is the function of arterioles?
Definition
primary resistance vessels; determine the distribution of cardiac output
Term
What is the function of capillaries?
Definition
site of exchange; determine the distribution of extracellular fluid between the plasma and the interstitial fluid
Term
What is the function of large veins and the vena cava?
Definition
passageway of the heart to the tissues; serve as a blood reservoir
Term
How arteries and arterioles act as pressure reservoirs?
Definition
the elastic walls collapse inwards during ventricular diastole (when there is less blood in the arteries)
Term
In humans, what is the range for blood pressure?
Definition
120 mm Hg during systole and 80 mm Hg during diastole
Term
What is the difference between systolic and diastolic pressure called?
Definition
the pulse pressure
Term
Arterioles distribute ___________ among _______ whose needs vary over time.
Definition
cardiac output, systemic organs
Term
____________ varies as a result of vasodilation and vasoconstriction.
Definition
resistance (and therefore blood flow)
Term
What two factors influence the radius of arterioles?
Definition
  • intrinsic (local) control due to increased CO2 or decreased O2
  • extrinsic control due to the autonomic nervous system
Term
Sympathetic ______. Parasympathetic _________. 
Definition
dilates, constricts
Term
What are capillaries?
Definition
the site of exchange for materials between blood and tissues
Term
Exchange may occur by ___________.
Definition
simple diffusion
Term
What characteristics enhance diffusion at capillaries?
Definition
  • thin capillary walls
  • narrow capillaries (so the red blood cells and plasma are close to the walls)
  • large numbers, providing alot of surface area
  • relatively slow flow of blood (providing more time for exchange to occur)
Term
How thick are the walls of capillaries?
Definition
one cell thick
Term
How many capillaries do humand have?
Definition
10-40 billion
Term
What is another way that exchange may occur at capillaries?
Definition
  • through pores (located between the cells that form the capillary walls)
  • by vesicular transport (ex: pinocytosis)
  • by bulk flow
Term
What is the function of the water-filled pores in the capillary wall?
Definition
they permit passage of small, water soluble sunstances that can cannot cross the endothelial cells themselves
Term
What types of substances pass through the endothelial cells of capillaries? Give examples.
Definition
lipid soluble substances; O2 and CO2
Term
Give specific examples of sunsatnces that can pass through the pores in the capillary walls.
Definition
Na+, K+, glucose, amino acids
Term
What type of substances are exchanges across the capillary walls via vesicular transport?
Definition
exchangable proteins
Term
Can plasma proteins cross the capillary wall?
Definition
no
Term
Interstitial fluid acts as an ____________ between blood and cells.
Definition
intermediary
Term
What happens to capillaries during resting conditions? What structure allows this?
Definition
they are closed ; pre-capillary sphincters
Term
What is the function of pre-capillary sphincters?
Definition
they act as stop cocks to control blood flow through the particular capillary
Term
When tissue metabolic activity increases, what happens?
Definition
  • the level of O2 decreases and the level of CO2 increases, causing relaxation of the pre-capillary sphincters and arteriolar vasodilation
Term
What is the function of veins?
Definition
they serves as low-resistance passage-ways to return blood from the tissues to the heart
Term
What extrinsic factors enhance venous return?
Definition
  • sympathetic activity 
  • skeletal muscle activity
  • respiratory activity
  • cardiac suction
Term
How does skeletal muscle activity enhance venous return?
Definition
muscle contraction increases venous return (skeletal muscle pump)
Term
How does respiratory activity increase venous return?
Definition
the lower atmospheric pressure in the chest cavity helps to bring blood from the lower body
Term
How does the skeletal muscle pump work?
Definition
  • when a skeletal muscle contracts, the upstream venous valve closes so that there is no backflow and blood is squeezed on to the next section of vein where the valve is open
Term
Veins serve as a ____________.
Definition
blood reservoir
Term
Under resting conditions, how much of your blood is located in the veins? Because of this, veins are important  in permitting changes in __________.
Definition
2/3; stroke volume 
Term
What is lymph?
Definition
the interstitial fluid that is picked up by vertebrate lymphatic vessels and returned to the venous system, meanwhile passing through the lymph nodes for venous purposes
Term
What structures are included in the lymph system?
Definition
lymph nodes, bone marrow, liver, spleen, and the thymus
Term
What are the functions of the lymphatic system?
Definition
  • absorbs excess fluid, thus preventing tissues from swelling
  • defends the body against microorganisms and harmful foreign particles as part of the immune system
  • facilitiates the absorption of fat
Term
What are the factors that affect blood pressure?
Definition
  • peripheral resistance (vessel diameter, blood viscosity, vessel length)
  • cardiac output (or heart rate combined with stroke volume)
  • vessel elasticity
  • blood volume
Term
Obesity increase vessel _______.
Definition
length
Term
What is coronary circulation?
Definition
circulation of blood in the blood vessels that supply blood to and from the heart muscle 
Term
What happens when there is reduced O2 in the cardiac myocytes?
Definition
  • adenosine release
  • vasodilation of coronary vessels
  • increased blood flow and O2 delivery to cardiac myocytes
Term
What are the main energy sources for the heart (from oxidative phosphorylation)?
Definition
  • fatty acids, glucose, and lactate
Term
What is the major energy source for the heart in normal adults?
Definition
fatty acids
Term
What is the major energy source for the heart in a fetus?
Definition
glucose
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