final exam concepts/terms: cardiac muscle

Question 1

What is similar/different between skeletal muscle and cardiac muscle?

Answer 1

similar: sarcomere is basic contractile unit, both striated.

differences: skeletal muscle under voluntary control and cardiac muscle is involuntary control

Question 2

What are the
functions of the desmosomes and gap junctions

Answer 2

desmosomes form tight connections so cardiac cells don’t pull apart. gap junctions provide channels for electrical continuity and propogation throughout the heart

Question 3

What in general is the profile and time frame of: cardiac pacemaker cells, cardiac contracting cells?

Answer 3

pacemaker cells: autorhythmic cellls

Question 4

what is a pacemaker potential? what causes it?

Answer 4

the gradual increase in voltage across the membrane of a heart’s pacemaker cells between ap’s.

caused by spontaneous changes in opening and closing of sodium, potassium, and calcium channels

Question 5

why can’t cardiac myocytes summate?

Answer 5

because they have a long refractory period

Question 6

what is the ANS?

Answer 6

autonomic nervous system

Question 7

how many divisions are in the ANS and what are they?

Answer 7

2: sympathetic (fight or flight) and parasympathetic (rest and digest)

Question 8

ANS anatomy

Answer 8

1. uses two neurons which meet in ganglion (pre-ganglion/postganglionic neurons)
2. entire SNS can be activated simultaneously b/c of chain ganglion
3. almost all organs have dual innervation; exception is adrenal gland, sweat glands, and blood vessels - only sympathetic

Question 9

how does the ANS affect heart rate?

Answer 9

para:
vagus, cranial nerve X
NT = ACh
slower depolarization
slows heart

sym:
fight or flight
NT = NE, EPI
faster SA depolarization
speeds up heart

Question 10

what is an ECG? what is it NOT?

Answer 10

electrocardiogram. a tool that measured electrical activity of the heart.

it is NOT an action potential

Question 11

what events do the P-wave, QRS complex, and T-wave represent?

Answer 11

p wave = atrial depolarization
qrs complex = ventricular depolarization
t wave = ventricular repolarization

Question 12

intercalated discs

Answer 12

structures that connect adjacent cardiac muscle cells

Question 13

desmosomes

Answer 13

proteins that form tight connections so cardiac cells do not pull apart

Question 14

gap junctions

Answer 14

clusters of cells that provide channels for electrical continuity and propogation throughout the heart

Question 15

syncitium

Answer 15

a single cell or cytoplasmic mass containing several nuclei formed by fusion of cells or by division of nuclei

Question 16

myogenic

Answer 16

originating in muscle tissue

Question 17

SA node

Answer 17

pacemaker that generates an electrical signal that causes the atrial upper heart chambers to contract

Question 18

sinus venosus

Answer 18

chamber in the heart responsible for controlling the heartbeat

Question 19

internodal fibers/pathway

Answer 19

A part of the heart’s conduction system that transmit electrical signals from the sinus node to the atrioventricular (AV) node and atrial myocytes

Question 20

AV node

Answer 20

nerve in the heart that controls the heart rate and connects the systems of the atria and ventrical

Question 21

bundle of his

Answer 21

bundle of cells that carries signals from the av node to the bundle branches

Question 22

purkinje fibers

Answer 22

branches of specialized nerve cells. L <–> R ventricles

Question 23

cholinergic

Answer 23

the neurotransmitter system in the brain that plays a crucial role in controlling activities related to selective attention and conscious awareness

Question 24

adrenergic

Answer 24

working on adrenaline or norepinephrine

Question 25

agonist antagonist

Answer 25

agonist: drug that mimics the action of the natural ligand antagonist: the general term of a drug that inhibits the action fo the natural ligand

Question 26

autorhythmicity

Answer 26

SA node will drive heart at rate of its spontaneous activity

Question 27

vagus nerve

Answer 27

nerve that be running up ur neck

Question 28

plataeu phase

Answer 28

Allows for a longer muscle contraction and gives time for the nearby cardiac muscle cells to depolarize.

Question 29

pvc

Answer 29

extra heartbeats that start in the heart's lower chambers, also known as the ventricles

Question 30

epinephrine

Answer 30

hormone known as adrenaline, vital in fight or flight

Question 31

pilocarpine

Answer 31

treats glaucoma and increases saliva production

Question 32

atropine

Answer 32

reduce saliva during surgery

Question 33

hcn

Answer 33

ion channels that are activated when membrane potential becomes more negative and is critical in rhythmic activity

Question 34

norepinephrine

Answer 34

a hormone, noradrenaline, that is apart of fight or flight

Question 35

acetylcholine

Answer 35

a chemical messenger acting like a neurotransmitter that allows for neurons to communicate with eachother