cardiovascular lecture 1

Question 1

what is the composition of blood

Answer 1

formed elements (cells and fragments) and plasma

Question 2

what percent of blood is plasma

Answer 2

55%

Question 3

what percent of blood are erythrocytes

Answer 3

45%

Question 4

what is the hematocrit

Answer 4

% of the blood volume that is composed of RBCs

Question 5

what is microcirculation

Answer 5

arterioles, capillaries, and venules

Question 6

what level of b.v does the exchange of molecules and nutrients occur

Answer 6

capillaries and interstitial fluid

Question 7

what allows people’s bodies to respond to a variety of circumstances

Answer 7

the dynamic adjustment of blood delivery

Question 8

how is blood delivery dynamically changed

Answer 8

via resistance. vasoconstriction/vasodilation

Question 9

why can 2 places with different absolute pressure have the same flow?

Answer 9

they can have the same local pressure distance and same resistance!

Question 10

what is the most important component in changing resistance

Answer 10

changes in vessel radii. (blood viscosity is a minor factor)

Question 11

what are the main differences b/w cardiac and skeletal muscle

Answer 11

• the cardiac cells are branched

- cardiac cells are connected via intercalated discs that contain gap ins within

Question 12

every cardiac cell contracts with every heart beat because of _______

Answer 12

gap ins which electrically couple cardiac cells

Question 13

parasympathetic cardiac innervation is via what nerve

Answer 13

the vagus nerve

Question 14

psymp innervation to the heart uses what neurotransmitter and what receptor

Answer 14

acetylcholine and a muscarinic receptor

Question 15

what part of the heart does psymp innervate

Answer 15

the atria (NOT THE VENTRICLE)

Question 16

sympathetic cardiac innervation is via what nerve

Answer 16

thoracic spinal nerves

Question 17

sympathetic innervation of the heart uses what n.t

Answer 17

norepinephrine

Question 18

what is the sympathetic HORMONE used in the “innervation” of the heart

Answer 18

epinephrine

Question 19

what receptor does the sympathetic system use for innervation of the heart

Answer 19

beta adrenergic receptors

Question 20

what part of the heart does the symp innervate

Answer 20

atria and ventricles

Question 21

atria and ventricles are electrically isolated via the _______

Answer 21

valves

Question 22

through what do the atria and ventricles “talk”

Answer 22

the AV node

Question 23

what is the order of the electrical stimulations of the heart

Answer 23

SA node—> AV node—->bundle of His—>R&L bundle branches—> purkinje fibers

Question 24

when the electrical signal gets to the AV node, the signal _____ to allow the atria to contract and ventricles to fill with blood

Answer 24

slows

Question 25

once the electrical signal gets to the bundle of his the signal ______ to allow for the propelling of blood from the ventricle

Answer 25

goes fast

Question 26

what is the significance of the SA node

Answer 26

it is the heart's pacemaker. initiates each wave of excitation via atrial contraction

Question 27

what does the P wave symbolize

Answer 27

atrial depolarization

Question 28

what does the QRS complex symbolize

Answer 28

ventricular depolarization

Question 29

what does the T wave symbolize

Answer 29

ventricular repolarization

Question 30

what is responsible for the rapid depolarization phase for ventricular myocardial cells

Answer 30

the opening and then rapid opening (when more depolarized) of VOLTAGE GATED Na channels. the permeability to Na has increased due to their opening.

Question 31

what is responsible for the plateau phase of the ventricular myocardial cells

Answer 31

1. slow-prolonged opening of the VOLTAGE GATED Ca channels | 2. the closure of the K channels

Question 32

what is responsible for the repolarization phase for ventricular myocardial cells

Answer 32

the opening of K channels

Question 33

do ventricular myocardial cells have a resting membrane potential

Answer 33

yes.

Question 34

what is responsible for the slow depolarization (threshold graded) phase of the nodal cells of the heart

Answer 34

1. F channels of Na (allowing the leaking in of Na into the cell) 2. and Ca moving in through channels

Question 35

what is responsible for the rapid depolarization phase of the nodal cells of the heart

Answer 35

rapid opening of VOLTAGE GATED Ca channels

Question 36

what is responsible for the repolarization phase of the nodal cells of the heart

Answer 36

1. reopening of K channels (allowing K out of the cell) | 2. closing of Ca channels

Question 37

what is the pacemaker potential

Answer 37

the slow depolarization phase of nodal cells that is caused by the F channels (for Na)

Question 38

do nodal cells have a resting membrane potential

Answer 38

no, they have a pacemaker potential

Question 39

do purkinje cells have a resting potential or a pacemaker potential

Answer 39

pacemaker. they have F channels. this is so they can spontaneously depolarize (at a slower rate) in case something happens to the AV node and the atria and ventricles can no longer communicate….a default pathway so that they heart will still pump!

Question 40

what part of an ekg corresponds to the rapid depolarization phase of a ventricular myocardial cell

Answer 40

the QRS complex

Question 41

what part of an ekg corresponds to the repolarization phase of a ventricular myocardial cell

Answer 41

the T wave

Question 42

what is a 3rd degree block

Answer 42

when the AV node isn't working and the atria and ventricle cannot communicate…they work separately. the QRS complex (ventricular depolarization/contraction) comes from the purkinje fibers and the bundle branches

Question 43

what is excitation contraction coupling

Answer 43

how the a.ps in the cardiac muscle are linked to a contraction

Question 44

what is the mechanism for excitation contraction coupling

Answer 44

1. depolarization of the membrane 2. opening of Ca channels in the t-tubules 3. Ca into the cytosol 4. Ca binding to the S.R 5. Ca released from the S.R into the cytosol 6. Ca contraction

Question 45

what is Ca induced Ca release

Answer 45

"trigger Ca" that binds to the S.R stimulates Ca to be released from the S.R and for more Ca to flow into the cytosol for contraction

Question 46

what is the purpose (2) of the plateau phase in cardiac muscle

Answer 46

1. allows Ca to come into the cell for contraction coupling 2. and allows for a LONG REFRACTORY PERIOD…for the ventricles to fill with blood, aka diastole (don't want the ventricles to be able to contract before they completely fill)