6 Flashcards
compare smooth skeletal and cardiac muscle in the following aspects: nucleus (number and where) t tubule presence z discs presence calcium binding protein banding cellular junctions nueromasuclar junctions
nucleus (number and where)
skeletal: multinucleate periphery
cardiac: one or two, centre
smooth: central one
z discs presence
skeletal: :YEs
cardiac: Yes
smooth: no (dense bodies instead)
t tubule presence:
skeletal: yes at AI triad
cardiac: yes at z disc died
smooth: no (dense bodies
cellular junctions
skeletal: none
cardiac: intercalated discs and gap junctions
smooth: gap junctions
calcium binding protein
skeletal: troponin
cardiac: troponin
smooth: calmodulin
banding
skeletal: yes clear band
cardiac: yes clear band
smooth: no clear bands
nueromasuclar junctions
skeletal: YES
cardiac: NO
smooth: NO
ribosomes of cardiac muscle
sarcoplasmic reticulum
sarcolemma
T tubule
mitochondria
structure of sarcomere
remember Mom is hugged by Hbibi who’s hugged by AbdelKader and everything that’s not abdelKader is I and Z is the other line parallel to mom
what types of cell to cell junctions are found in intercalated discs and what are their functions
gap junctions: electrical syncityum
desmosomes: keeps cells anchored to one another during contraction
fascia adherens: attaches sarcomeres to sarcolemma (cell membrane)
properties of cardiac mucscle
rythmicity
automaticity
no intrinsic nerve fibres
what what are the three ion channels that allow for firing of action potential
k
na
Ca
remember (NAc restaurant)
which ion channels allow for the depolarisation of the current
Na
Ca
which ion channels allow for the repolarization of the current
K
will all cardiomyocytes have an AP wave that looks the same=
no
what happens on a molecular level during refractory period
ion channels are closed so inactivated so AP cannot be generated.
how does calcium affect cardiac cells during contraction?
What process terminates contraction
calcium channels along with Na channels open during contraction.
calcium goes in.
increase in intracellular calcium will increase release of Ca from the SR.
Ca will bind toponin and form the CAtroponin myosin light chain kinase which will phosphorylate myosin heads. this will allow for contraction of the sarcomere
contraction terminates when Ca is released from the sarcomere and is reabsorbed by the SR.
what type of calcium channels foes calcium go in through
L type
how does the SNS module heart function
increase heart rate increases force of contraction increases BP secretes ADRENALINE acts on beta 1 receptors
how does the PNS module heart function
lower heart rate lower force of contraction lower BP secretes ACETYLCHOLINE acts on beta muscarinic receptors
whats the function of dense bodies
in smooth muscle cells, dense bodies help anchor thin and thick filaments.
functional equivalent of Z line.