Exam 2 Flashcards
Contractile cardiomyocyte
Contractive heart muscle cell
they exert pumping force, have many myofibrils, and have a high ability to contract
Conductive cardiomyocyte
conductive heart muscle cell
carries signals, few myofibrils and is autorhythmic
Myofibril
any of the elongated contractile threads found in striated muscle cells
Autorhythmic
can generate its own rhythm
the heart produces its own pulses through electrochemical stimuli originating from a small group of cells in the wall of the right atrium, known as the sinoatrial node
Striated
Contractile filaments parallel & highly organized
thick filaments are all in a row in parallel when needs to pul in one direction
Glycogen
Stored glucose, is in between myofibrils used when the heart needs more glucose to create energy
Myoglobin
store oxygen in muscle cells, a cell much like hemoglobin but only has 1 polypeptide, used to tie over the heart until blood supply catches up.
Anchoring junction
part of intercalated discs these junctions are going to hold together the cells. in a picture, they are the dark lines where the cells meet, lock together like velcro
Gap junction
Part of intercalated discs, they will transmit electrical contraction signals (responsible for electrical charging of cardiac muscle)
Na, K, Ca all can pass through the junctions
Conduction system
used to establish a heart beat
generate electrical signals & carry them throughout the heart
electrical signals cause contraction
innate rhythm adjusted by neural/endocrine signals
Depolarize
the cell undergoes a shift in electric charge distribution, resulting in less negative charge inside the cell compared to the outside.
Sinoatrial node
or pacemaker
Pacemaker
Otherwise known as the sinoatrial node
is a patch of conductive cells in the superior, posterior right atrium
Sinus rhythm
normal rhythm of the heart where electrical stimuli are initiated in the SA node
Interatrial band
or the Bachmann’s bundle, is to the left of the atrium
spread across to both atria, more conductive cells faster pathway to get to left atrium to contract at same time.
Bachmann’s bundle
otherwise known as the interatrial band
Atrioventricular node
(AV) node
will receive a signal hold it, and then sends it to the interventricular septum
delays signal so atria finish before ventricles start
Internodal path
spread of sinus rhythm in three pathways to AV nodes
Atrioventricular septum
Wall that divides the atrium & ventricle
Bundle of His
Or AV bundle is on top of the interventricular septum
an elongated segment connecting the AV Node and the left and right bundle branches of the septal crest
Atrioventricular bundle
Or Bundle of his
Interventricular septum
the triangular wall of cardiac tissue that separates the left and right ventricles
Bundle branch
conduct impulses to right and left ventricle (have a R&L)
move down the interventricular septum
Purkinje fibers
apical ends of branches, up ventricle walls
in walls of ventricles, cause the action of squeezing/pump
gets close to as many contractile cells as possible
Action potential
a rapid sequence of changes in the voltage across a membrane
Voltage gated channel
the basic ion channels for neuronal excitability, which are crucial for the resting potential and the generation and propagation of action potentials in neurons.
sodium channel
transmit depolarizing impulses rapidly throughout cells and cell networks
conductive Na: have slow depolarization
contractile Na: have fast depolarization
Threshold potential
the value of the membrane potential which, if reached, leads to the all-or-nothing initiation of an action potential
Calcium channel
structural components of cardiac cells that provide a mechanism to modulate the force of contraction
Conductive Ca: Rapid depolarization
Contractile Ca: hold the plateau
Potassium channel
particularly important in determining the shape and duration of the action potential, controlling the membrane potential
Conductive K: Repolarization
Contractive K: polarization
Repolarize
the change in membrane potential that returns it to a negative value just after the depolarization phase of an action potential
Resting potential
the electrical potential difference across the plasma membrane when the cell is in a non-excited state
when K+ channels close at -80mV
finish one cycle (causing contraction)
Refractory period
Prevents premature next contraction
resistant to open/close channels
Plateau period
where Ca2+ and K+ are being released at the same time one going in one going out. K is going slightly faster but Ca causes it to slow repolarization
Electrocardiogram
monitoring the electrical signals of the heart
P wave
atria depolarize, contracting immediately after
QRS wave
atria repolarize, ventricles depolarize
T wave
ventricles repolarize causing relaxation
compare the number of myofibrils of contractile cardiomyocytes to conductive cardiomyocytes
compare the strength of contractile cardiomyocytes to conductive cardiomyocytes
compare autorhythmicity of contractile cardiomyocytes to conductive cardiomyocytes
How are cardiomyocytes specialized to contract all your life with only short relaxation periods with regard to type of respiration
How are cardiomyocytes specialized to contract all your life with only short relaxation periods with regard to number of mitochondria
How are cardiomyocytes specialized to contract all your life with only short relaxation periods with regard to oxygen storage
How are cardiomyocytes specialized to contract all your life with only short relaxation periods with regard to glucose storage
What makes striations in cardiac and skeletal muscles
size of cardiac compared to skeletal muscles
compare the shape of cardiac vs skeletal muscle
compare how many nuclei are in each cell for cardiac and skeletal
What are the functions of intercalated disk
Why do intercalated discs fold back and forth
what is the role of anchoring junctions
What are gap junctions for
What is the relationship between depolarization and contraction
Why is it important to delay the heart depolarization at the AV node
Where is the sinoatrial node located
How dose the sinus rhythm override spontaneous depolarization of the other conductive cells
What influences can increase or decrease the sinus rhythm
how does the sinus rhythm depolarization reach the other atrium
how does the sinus rhythm reach the AV node
How does the AV node alter the rhythm
Trace the path of a heart electric stimulus form its origin to its final destinations both in the walls of the atria and in the wall of the ventricles (look at conductive tissues along the way)
Why is it essential that Purkinje fivers start ventricular depolarization at the apex of the heart
How do Na+ and Ca2+ together account for rhythmic depolarization of a conductive cardiomyocyte, such as those in the SA node
How does Na+ channels role differ in contractile myocytes, as compared to conductive myocytes
How does Ca2+ channels role differ in contractile myocytes, as compared to conductive myocytes
What brings each type of cardiomyocyte up to threshold potential
How are gap junctions involved in depolarizing contractile cells
what is the refractory period especially important for contractile cardiomyocytes
Cardiac cycle
events from start to end of one heartbeat
Systole
cambers contract
Diastole
Chambers relax
Passive ventricular filling
heart itself is not doing any work, the atrium allowing blood into ventricles bc AV are open, SL closed (in diastole)
between T & P wave
gets 70-80% into heart
pressure in veins is higher than that in the heart
Atrial systole
Contraction triggered by P wave
AV open, semilunar closed
forces more atrial blood into ventricles
Ventricular systole
the ventricles are contracting and vigorously pulsing two separated blood supplies from the heart
Isovolumetric contraction
no change in volume, this builds pressure so when the valve opens it can make it all over
events triggered by QRS wave
S1
the first sound Lub
the closing of the AV valves results in turbulence in the blood
Lub
this is S1
This is the sound that happens when the ventricles contract the back pressure closes the AV valve.
with all valves shut increase ventricular tension & pressure
Ventricular ejection
ventricles still contracting, atria still relaxed
the increased ventricular pressure forces semilunar valves to open
Isovolumetric relaxation
part of ventricular diastole
instead of building pressure, we are decreasing pressure which closes Semilunar valves to prevent back flow
ventricular diastole triggered by T wave
Relaxation of chambers
S2
Closing of the valves & turbulence creates the second heart sound
Dub
second sound
What forces cause atrioventricular valves to open
What forces atrioventricular valves to close
What forces the semilunar valves to open
what forces the semilunar valves to close
what are the names of the heart sounds
What causes each heart sound
What are the five phases of the cardiac cycle
Cardiac output
Blood/min= HR * SV (4-8 L/min)
Stroke volume
blood from ventricle/ beat, 55-100 mL
(tennis swing)
Heart rate
Beats/min 60-100 bpm
can be affected by nerves, hormones
Echocardiogram
ultrasound for the heart
Ejection fraction
is the fraction pumped out by the ventricle
calculated by SV/ total volume (EDV) x 100
End diastolic volume
volume after heart was resting
End systolic volume
volume after ventricular systole, amount after contraction
Bradycardia
low heart rate
Tachycardia
High heart rate
Target heart rate
To hold the maximum Cardiac output it is 50-80% of the max heart rate
cardiac reserve
is the maximum cardiac output - resting cardiac output
Proprioceptor
are receptors in joints, tendons & muscles
they will sense our position (close eyes and touch nose)
ex. working out need to increase CO
Baroreceptor
measures blood pressure
pressure receptors are sinuses
measures arterial pressure, systemic circulation pressure, and pressure in the aorta
Aortic sinus
The baroreceptor is in the aortic sinus
one of the anatomic dilatations of the ascending aorta, which occurs just above the aortic valve
Carotid sinus
a dilation at the base of the internal carotid artery
Cental Chemoreceptor
measures CO2, pH in the blood, located in the medulla oblongata
Peripheral chemoreceptor
measures CO2, pH, and O2 in aortic and carotid bodies
Aortic body
a collection of nonchromaffin paraganglion cells
next to barorecepters
Carotid body
a small mass of receptors in the carotid artery sensitive to chemical change in the blood
Parasympathetic system
Used to slow down cardiac output
rest and relax
cardioinhibitory center
placed in the medulla oblongata is going to inhibit cardiac output
(slows cardiac function by decreasing heart rate and stroke volume)
Medulla oblongata
the bottom-most part of your brain. Its location means it’s where your brain and spinal cord connect, making it a key conduit for nerve signals
Vagus nerve (Cranial nerve X)
Path for efferent signal in the parasympathetic pathway, to the cardiac plexus
Cardiac plexus
A bunch of nerves at the base of the heart formed by cardiac branches from sympathetic and parasympathetic systems
Acetylcholine
hyperpolarizes the myocardium
the neurotransmitter in parasympathetic system
Neurotransmitter
send signals
Sympathetic system
fight or flight, one of the divisions of the autonomic nervous system
activates when heart rate is too low
Cardioacceleratory center
going to send the signal to speed up the heart rate and cardiac output
located in the medulla oblongata
Chain ganglia
is a collection of neuron cell bodies outside the CNS beside the spinal cord going in a chain down the spinal cord
Cardiac nerve
goes from the chain ganglia to the cardiac nerve that will run from the spinal cord to the heart
Norepinephrine
is a neurotransmitter used in the sympathetic nervous system
is used to reduce repolarization of myocardium
Atrial (Brainbridge) reflex
also called atrial reflex
stretch indicates venous return tighter than cardiac output
increase the heart rate to increase cardiac output to catch up to venous return
Preload
pressure in ventricles from end-diastolic volume
Contractility
Fore of the contraction fo the heart muscle
more pressure in the ventricles going to push harder
Starling’s law
higher pressure –> greater contractility
Afterload
pushing harder to get blood out
resistance in arteries to ventricular ejection decreases SV
Back pressure on semilunar reduces stroke volume
Stenosis
“narrowing”, stiffening
stenosis will increase afterload and reduce SV
Vasular resistance
the amount of force exerted on the blood by the vessels
Atherosclerosis
another word for vascular constriction
will increase afterload
Tunica intima
the luminal surface
endothelium layer made up of a simple squamous epithelium
Basement membrane
areolar tissue
internal elastic membrane
Another name for Tunica intima is…
tunica interna
Epithelial membrane
the innermost part of the luminal structure
Endothelium
simple squamous epithelium
Basement membrane
binds to the epithelial layer and binds underlying C.T
Areolar tissue
loose fibrous connective tissue
has a fenestrated internal elastic membrane
Internal elastic membrane
used to help stretch when the ventricles pump, is zigzag ish in structre
Fenestration
small holes that will allow for O2 & CO2 to pass through
Tunica media
muscular layer, like the myocardium in heart
smooth muscle for vasoconstriction
Vasoconstriction
will constrict the blood vessels to increase pressure and decrease flow
Vasodilatation
when the smooth muscle relaxes, will increase flow and decrease BP
Myofiber
muscle fibers, in between them is collagen & elastic fibers
vasa vasorum
embedded vessels for superficial layers
blood vessels of blood vessels
in tunica media
Nervi vasorum
sympathetic nerves control the smooth muscle
in the tunica media
External elastic membrane
fenestrated to allow for gas exchange same as internal
Tunica externa
areolar connective tissues anchor vessels in place
has nervi vasorum & vasa vasorum
What is another name for tunica externa?
Tunica adventitia
Elastic artery
conduct blood to different parts of the body
nearest to the heart, stretch to absorb hart force during systole, then rebounds to maintain flow in diastole
What is another name for the elastic artery?
Conducting artery
Muscular artery
slight change
branch from elastic, more muscles, less elastic fibers, muscle allows for vasoconstriction & BP management
What is another name for the muscular artery?
Distributing artery
Arteriole
can control blood flow (major role in BP)
less tunica media, large numbers & length reduces blood pressure, critical in control of local blood distribution
Another way to describe the arteriole is….
resistance vessel
Capillary
Tunica intima only, site of gas exchange
three different types (continuous, fenestrated, sinusoids)
Continuous capillary
common, clefts only between endothelial cells
Fenestrated capillary
clefts, pores in kidneys, intestines, glands, and choroid (cerebral spinal fluid maker)
Sinusoid
fenestration, gaps
located in the marrow, liver, spleen & endocrine glands
Venule
collect blood from capillary beds
thin tunica external & tunica media
Venoconstriction
constricting of the veins
used to adjust blood reservoir function
Blood pressure
(BP)
Blood flow
(Q)
Vascular resistance
(R)
Systolic pressure
peak arterial pressure at systole
Diastolic pressure
minimum arterial pressure at diasole
pulse pressure
systolic - diastolic pressure
0 with distance
Mean arterial pressure
the diastolic pressure + (pulse pressure/3)
Sphygmomanometer
blood pressure cuff
air cuff pressure occludes the artery
Korotkoff sounds
sounds made by the squirting of blood through partially occulted artery
Viscosity
how thick the blood is
increase in viscosity, increase R
harder to push through blood vessels (polycythemia increase v, liver damage decrease v)
Compliance
(C)
how easily does it stretch
more compliance decreases resistance, increases flow & decreases pressure
Arteriosclerosis
reduces compliance and increases BP
it is the stiffening of the arteries, which can cause a build-up of blood that can cause a thrombosis/embolus
Cross-selection area
(A)
how big around something is
more cross-section decreases resistance, pressure, velocity & BP, it will increase flow
Blood velocity
the distance at which the blood moves
Hypervolemia
too much blood volume
by water and salt retention
ex kidney disease
Hypovolemia
by dehydration, bleeding, vomiting, diarrhea
Skeletal muscle pump
veins b/w skeletal muscles or b/w muscle & bones, when contracted will squeeze blood toward the heart, have one-way valves to prevent backflow
Respiratory pump
when inhaled decreases the pressure in the thoracic, causing the blood to move from the abdomen to the chest (high to low), then exhale it increases the pressure in the thoracic cavity pushing the blood into the atrium where there is less pressure
Direct diffusion
movement from high to low [ ]
molecules that are uncharged or non-polar, also ones that are hydrophobic
oxygen, carbon dioxide
hydrophobic molecules
lipids, steroids, fat-soluble vitamins
facilitated diffusion
small molecusles that are charged (polar), and hydrophilic
go through a transport protein
transport protien
hydrophilic on the inside, hydrophobic on the outside
can open and close like a window
vesicular transport
larger particles (proteins)
can store stuff in the membrane, a bubble inside the cell
endocytosis
process inside the cell (getting inside the cell)
exocytosis
process on the other side of cell to leave/ release
transcytosis
the whole process of endo & exo across the cell is transcytosis
getting a protein from liver cells to the blood vessels
bulk flow
movements of liquids (water, solutes, colloids) b/w gaps in epithelium
filtration
hydrostatic pressure
Reabsorption
Colloid
Colloid osmotic pressure
Net filtraiton pressure
Lymphatic system
