CHAPTER 12: CARDIOVASC Flashcards
systole
contraction phase of cardiac cycle
diastole
relaxation phase of cardiac cycle
components of circulatory system
heart, blood vessels, blood
blood is composed of formed elements suspended in a liquid called ______
plasma
red blood cells are known as:
erythrocytes (carry oxygen to the tissues, and carries co2 from the tissues)
white blood cells are known as:
leukocytes (protect against infection and cancer)
cell fragments are known as:
platelets (function in blood clotting)
hematocrit
percentage of blood volume that is erythrocytes
measured by centrifugation of a sample of blood
mean arterial pressure =
cardiac output * total peripheral resistance
cardiac output
the amount of blood pumped out of each ventricle in one minute
= heart rate * stroke volume
normal heart rate is =
normal stroke rate =
normal cardiac output =
72 beats/min
70 mL
5 L/min
in a healthy system, stroke volume is…
fairly constant
what increases heart rate?
positive chronotropic factors
what decreases heart rate?
negative chronotropic factors
stroke volume is the difference between what two things?
end diastolic volume and the end systolic volume (SV = EDV = ESV)
with every heart beat, the heart pumps around ___% of the blood in its chambers (70 mL)
60%
frank-starling’s law
states that the stroke volume increases with increased end-diastolic volume (think hooke’s law F=-kx)
afterload
pressure that the ventricles must overcome to force open the aortic and pulmonary valves
preload
critical factor that controls stroke volume – it is the degree to which the cardiac muscle cells are stretched before they contract
proportional to ventricular myocardial fiber stretch
most important factor in causing stretch
amount of blood in the ventricles (controlled by venous return)
ventricular contractility
strength of contraction at any given ED volume
slower heart rate, exercise =
increase in end diastolic volume
components of plasma
dissolved nutrients, plasma proteins, albumins, globulins, fibrinogen (func: transport of ^^^)
sympathetic stimulation increases the slope of the pacemaker potential by…
increasing F-type Na+ channel permeability –> causing SA node cells to reach threshold more rapidly (increasing heart rate)
parasympathetic stimulation ____ heart rate & _____ SA node cell permeability to K
reduces & increases –> takes longer to reach threshold
ejection fraction
ratio of stroke volume to end diastolic volume
anything that increases EDV and force of ventricular contraction can increase…
stroke volume
extrinsic controls of stroke volume:
1) sympathetic drive to ventricular muscle fibers
2) hormonal control
serum
plasma with fibrinogen + other proteins involved in clotting REMOVED from it
multipotent hematopoietic stem cells
undifferentiated cells capable of giving rise to percursors of blood cells
hemoglobin
protein prudced by erythrocytes –> oxygen and Co2 reversibly combine
bone marrow
site of erythrocyte production is the soft interior of bones
reticulocyte
young erythrocytes that contain ribosomes and are reticular-shaped
because erythrocytes lack nuclei and most organelles, they cannot do what?
they cannot reproduce themselves nor maintain their normal structure for very long
major breakdown product of hemoglobin that gives plasma its yellowish color is called:
bilirubin
oxygen binds to which element on a hemoglobin molecule within an erythrocyte
iron
iron deficiency
results from significant disruption of iron balance –> inadequate hemoglobin production
hemochromastosis
excess iron in the body
where does body store iron in the liver?
bound up in a protein called ferritin
where does the iron released into plasma from old, destroyed erythrocytes in the spleen/liver bind to?
bound to a protein called transferrin (also delivers this iron to bone marrow for new erythrocytes)
folic acid
vitamin found in plants, yeast, liver, and required for synthesis of nucleotide base T
(fewer erythrocytes are produced when folic acid is deficient)
what vitamin is required for both action of folic acid & normal erythrocytes (in small amounts)?
vitamin B12
erythropoiesis
iron + folic acid + b12 are present for normal erythrocyte production
erythroprotein
hormone that controls erythropoiesis and is secreted into the blood by a group of connective-tissue cells in kidneys
endothelium
smooth, single-celled layer of endothelial cells in contact with flowing blood in all BVs and chambers
pressures _______ as blood flows from ventricles through capillary beds to atria because of resistance to flow
decrease
entire cardiovasuclar system contains:
single-celled layer of endothelium and connective tissue –> lines inner (blood contacting) surface of vessels
capillaries consist of:
endothelium and a EC membrane
venules consist of:
endothelium and connective tissue
elastic arteries components:
-large lumen vessels near the heart that carry blood for circulation
-low resistance, more elastin than muscular arteries
-“pressure reservoirs” = expand and contract as blood is ejected by heart
-continuous blood flow
atherosclerosis
buildup of plaque that blocks blood flow & affects proper functioning
arteriosclerosis
hardening of arteries & affects proper functioning
compliance =
change in volume / change in pressure
only about ___ of the stroke volume leaves the arteries during the stroke
1/3 (rest remains in arteries)
passive recoil
arties continue to drive blood into the artery by elastic return or spring-back of tissues, like muscles or lung tissue, after being stretched or compressed
(natural)
muscular arteries components:
-deliver blood to specific organs
-contain layers of smooth muscle used for constriction
-regulation of blood pressure
average blood pressure =
120/80 mm Hg (more = hypertensive)
pulse pressure
difference between systolic and diastolic pressure (ex: 120-80 = 40 mm Hg)
factors that determine |pulse pressure|
stroke volume, speed of ejection of blood, arterial compliance
arterioles characteristics
-smallest arteries
-function is controlled by neural, hormonal, local chemicals
-control minute-to-minute blood flow into the capillary beds
active hyperemia
response to INCREASED METABOLIC ACTIVITY = increased blood flow (relaxation of arteriolar smooth muscles is due to local chemical changes in surrounding EC fluid)
flow autoregulation
ability of individual arterioles to alter their resistance in response to changing blood pressure so that relatively constant blood flow is maintained
mean arterial pressure (MAP) =
cardiac output x total peripheral pressure
anemia
decrease in ability of the blood to carry oxygen due to:
-decrease in # of erythrocytes
-diminished [ ] of hemoglobin per erythrocyte
sickle-cell disease is due to what?
a genetic mutation that alters one amino acid in the hemoglobin chain
polycythemia
more erythrocyte production than normal
neutrophils
-type of leukocyte found in the blood
-engulf microbes like bacteria by phagocytosis
-infections
eosinophils
-type of leukocyte found in the blood + mucosal surfaces
-fight off invasions by parasites by releasing toxic chemicals (or phagocytosis)
monocytes
-type of leukocyte that circulate in blood for a short time
-migrate into tissues/organs and develop into phagocytosis
venous pressure pumps
1) respiratory pump (pressure due to breathing, helps propel blood back to the heart due to negative pressure)
2) muscular pump (muscle contraction = blood moving forward and towards heart)
macrophages
-type of leukocyte that encounters invaders
-can engulf viruses and bacteria
basophils
-type of leukocyte that secretes anticlotting factor + helps circulation flush out the infected site
-secretes histamine
lymphoctyes
-type of leukocyte composed of T and B lymphoctyes
-can directly kill pathogens or secrete antibodies into circulation
hematopoietic growth factors
large # of protein hormones and paracrine agents that stimulate proliferation and differentiation
bulk flow
rapid flow of blood throughout body produced by pressures from pumping of the heart
movement between the interstitial fluid and the cell interior are accomplished by both _____ and mediated _____ across plasma membrane
diffusion and mediated transport
what is the upper chamber and lower chamber of the heart?
upper = atrium, lower = ventricle
1) pulmonary circulation
blood pumped from right ventricle through lungs and then to the left atrium
2) systemic circulation
blood pumped from the left ventricle through all organs and tissues of body, and then to right atrium
arteries
vessels carrying blood away from heart
veins
vessels carrying blood from body organs and tissues back toward the heart
aorta
the single large artery that blood leaves the left ventricle using
smallest arteries branch into:
arterioles
capillaries
very small vessels that connect arteries and veins. also responsible for delivering oxygen and nutrients to cells and removing waste products like carbon dioxide
venules
the smallest veins and receive blood from capillaries & are sites of migration of leukocytes from the blood into tissues
veins
low-resistance, high-capacitance vessels carrying blood BACK to the heart
microcirculation
arterioles + capillaries + venules
inferior vena cava
one of the large veins which collects blood from below the heart
superior vena cava
one of the large veins which collects blood from above the heart
blood leaves right ventricle via ______ (large artery), which divides into the two ______ ______, one supplying right lung and the other left
pulmonary trunk, pulmonary arteries
how does blood leave the lungs?
via 4 pulmonary veins (empty into left atrium)
as blood flows through capillaries of peripheral tissues and oxygen, what happens to oxygen content?
results in lower oxygen content of blood because some oxygen diffuses out to be used by cells
lungs receive all blood pumped by ____ side of heart
right
hemodynamics
relationship among blood pressure, blood flow, and resistance to blood flow
hydrostatic pressure
pressure exerted by any fluid (high –> low pressure)
resistance to blood flow
how difficult it is for blood to flow between 2 points at any given pressure difference
equation explaining resistance
friction = pressure difference/resistance
viscosity
function of friction between molecules of a flowing fluid that determines resistance
resistance is directly proportional to both _____ and ______, and inversely proportional to _______
directly: fluid viscosity and vessel’s length
inversely: 4th power of vessel’s radius
pericardium
the protective fibrous sac that the heart is enclosed in
epicardium
fibrous layer closely affixed to the heart
what is the extremely narrow space between the pericardium and epicardium filled with?
its filled with a watery fluid that serves as lubricant as the heart moves within the sac
myocardium
wall of the heart composed primarily of cardiac muscle cells
what is the inner surface of cardiac chambers & inner wall of all blood vessels lined with?
a thin layer of endothelial cells (endothelium)
interventricular septum
the muscular wall that separates the two ventricles
atrioventricular (AV) valves
the one-way valves that permit blood to flow from atrium to ventricle (but NOT backward) - located between atrium and ventricle in each half of the heart
right AV valve is called ____ and left AV value is called ____
right = tricuspid valve (3 flaps)
left = bicuspid valve (2 flaps)
left can also be called mitral valve
the opening and closing of the AV values are processes that result from what?
pressure differences across the valves
what prevents the AV valves from being pushed up and opening backward into the atria?
the valves are fastened to muscular projects (papillary muscles) of the walls by fibrous strands
pulmonary and aortic valves
valves located at the openings of the right ventricle into the pulmonary trunk & of left ventricle into the aorta that allow blood to flow into the arteries (only one-way)
approximately __% of cardiac cells do not function in contraction (but have other features for normal <3 excitation)
1% - *they are part of of a network called conducting system that is in electrical contact with cardiac muscle cells
innervation
a complex network of both sympathetic and parasympathetic nerves that regulates heart rate, rhythm, and contractility
coronary arteries
arteries supplying blood to the myocardium (coronary blood flow)
sinoatrial (SA) node
initiates depolarization in a small group of conducting-system cells –> generates AP + depolarization of
discharge rate of the SA node determines what?
heart rate (# of <3 contractions per minute)
atrioventricular (AV) node
conducting link between atrial depolarization and ventricular depolarization - located in right atrium
(propagation of APs through AV node is relatively slow)
how is AP conducted rapidly from SA node to AV node?
via internodal pathways
bundle of His
conducting-system fibers (divide into right and left branches)
purkinje fibers
large and rapidly-conducting cells connected by low-resistance gap junctions
L-type Ca2+ channels
L=long-lasting channels that open much more slowly than do Na+ channels, remain open for a prolonged period
F-type channels
open when membrane potential is at negative values, conduct a mainly inward Na+ current
T-type channels
T=transient, opens briefly but contributes towards inward Ca2+ current
electrocardiogram
tool for evaluating the electrical events within the heart – APs occur simultaneously and currents are conducted throughout the body fluids around the heart
P wave
current flow during atrial depolarization (first deflection)
QRS complex
result of ventricular depolarization
T wave
ventricular repolarization (final deflection)
absolute refractory period
period during and following an action potential when excitable membrane cannot be re-excited
due to inactivation of Na+ channels
isovolumetric ventricular contraction
ventricles are contracting BUT no blood can be ejected
volume of blood ejected from each ventricle during systole
stroke volume
isovolumetric ventricular relaxation
when ventricular is not changing because no blood is entering or leaving ventricles (AV values are closed)
“lub”
low-pitched heart sound, AV valves are closing
“dup”
loud heart sound, pulmonary and aortic valves valves closing
laminar flow
blood flows through valves/vessels in smooth concentric layers
heart murmurs
due to narrowed or leaky valves, holes in septum, turbulent flow
echocardiography
used to obtain 2D, 3D images of the heart throughout the cardiac cycle (wall/valve function)
cardiac angiography
assesses coronary artery patency and blood flow
