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.
what are some structural features of smooth muscle fibres
thin and thick filaments attached via dense bodies.
intermediate filaments allow for propagation of force generated by contraction .
how do smooth muscle fibres run
obliquely
how do smooth muscles attach to one another and to the PM
electrically via gap junctions
mechanically join PM at junctional complexes
where is smooth muscle found
in walls of arteries
uterus
urinary bladder
wall of visceral organs
what do action potentials on smooth muscle fibres look like compared to cardiac muscle
Cm: single spikes separated by plateau
SM: slow waves with peaks
duration of AP in smooth muscle vs skeletal duration
smooth 10-15ms
skeletal 2 ms
what ion Chanel does depolarisation mostly need
calcium
which channel open faster Na or Ca
Na
What are varisocisites and where are they found
around smooth msucle
they contain neurotransmitter that they release and are picked up by receptors widely distributed along smooth muscle fibre
what are the two types of smooth muscle cell organisation
multi unit smooth muscle:
each fibre is innervated independently from its neighoubr
iris of the eye, large blood vessels
single unit smooth muscle:
muscle fibres form a network and innervation of one propagates the innervation to others
uterus
innervation of visceral muscle gut. Sauf heart
how does calcium affect smooth muscle 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 can also go in if an agonist to LCCC binds and releases IP3 which triggers release of Ca from SR
Ca will bind almodulim and form the CAcalmodulinmyosin light chain kinase which will phosphorylate myosin heads. this will allow for contraction of the sarcomere
thin filaments slide under thick filament and intermediate filaments propagate force of contraction
contraction terminates when Ca is released from the sarcomere and is reabsorbed by the SR.
how is vascular muscle cell controlled in terms of PNS and SNS
SNS leads to vasoconstriction of smooth muscle
smaller vessels.
via alpha 1 adrenergic receptors (SNS releases adrenaline)
PNS leads to vasodilation of smooth muscle
larger vessels.
via beta 2 receptors (PNS releases acetylcholine)
how is bronchial muscle cell controlled in terms of PNS and SNS
SNS leads to bronchodilation
larger bronchi
via beta 2 receptors
PNS leads to vasodilation of smooth muscle
smaller bronchi
via M3 muscarinic receptors (PNS releases acetylcholine)
treatment for too much sympathetic effect on bronchi
SABA
LABA
treatment for too much parasympathetic effect on bronchi
SAMA
LAMA
