Histology
Team
Lecture 5
Clinical Pharmacy
Cairo University
/Clinical2020CU
2014/2015
pg. 1
Lecture IV: Muscular Tissue

GENERAL CHARACTERISTICS OF THE MUSCULAR TISSUE
o Mesodermal in origin
o It is formed of specialized elongated cells(muscle fibers) containing contractile
filaments (actin & myosin).
*en feha actin we myosin de 5asya lel 5laya el 3dalya
o Interaction of these filaments adapts the muscle cells to contract.
o Muscle fibers are the structural & functional unit of the muscles
o the cell membrane of the muscle fiber is called SARCOLEMMA and cytoplasm is
called SARCOPLASM
*HENA EL MEMBRANE BTA3 EL MUSCLE FIBER M4 ZY 2Y CELL BUT CALLED SARCOLEMMA ALSO
CYTOPLASM CALLED SARCOPLASM(sarco y3ny meat y3ny muscle)

TYPES OF MUSCLES:
3NDY B2A 3 TYPES MN ELL MUSCLES DE , TB WAIT KDA YATARAAA HMA MT2SMEN 3LA 2SAS
EAAAA
1- SHAPE OF THEIR CELLS
2- FUNCTIONS OF THEIR CELLS
TYBBBBBB MT2SMEEEEN LE EAAA HAA LE EAAAA
1- SKELETAL MUSCLE (attached to skeleton)also called striated cauz dark lines & light lines (
due to actin & myosin in myofibrils)
2- CARDIAC MUSCLE(fe 3dlet el 2lbbbbb)
3-SMOOTH MUSCLE(btkon fe gdar el blood vessiles in origin of systems like digestive
system.....)
*HNLA2Y FEL CELLS DE ENHA BT5ZN EL CALCIUM LAW MFE4 2NKBAD WE TDO5O DURING
CONTRACTION FEL( sER) 3L4N DA RESERVE PUMP 3L4N YSA3ED 3LA SLIDING OF ACTIN &
MYOSIN
*BARDO HNLA2Y MYGLOPEN ELLY HWA EA PROTEIN PIGMENT DA MS2OL 3N RED COLOUR OF
THE MUSCLE HAS ABILITY ENO YTFA3L M3 OXYGEN BYGEBO MN EL BLOOD WE Y7WE4O FEL
MUSCLE FIBERS CAUZ OXIDATIVE PHOSPHORELATION OF MITOCHONDRIA 3L4N EL ENERGY
SUPPLY
pg. 2
SKELETAL MUSCLE
SITES
Most of these muscles are attached to the skeleton , except those
in:face,tongue,pharynax(‫ & )البلعوم‬uppear 1/3 esophagus (‫ )التلت االول من المرئ‬diaphram ‫الحجاب‬
‫ & الحاجز‬cremasteric muscles de fel male genital system )skeletal muscle ‫) كل دول فيهم‬
V.I : pharynx & 1/3 uppear of esophagus ,diaphragm& cremasteric muscles ) THESE ORIGINS
HAVE SKELETAL MUSCLE BUT NOT NOT NOT VOLUNTARY WE CANT CONTROL THEM JUST
THEY HAVE SKELETAL MUSCLE IN STRUCTURE BUT NOT IN FUNCTION)
ORGANIZATION:
FROM SMALLER TO BIGGER LETS GOOOOO
MYOFIBRILS(have actin & myosin to contract)>>>>MUSCLE FIBERS( ‫مقلمات‬
‫>>>>)كتير‬BUNDLes(‫>>>>>)حزمات‬MUSCLE
...yb2a el muscle el kbera we de gwaha bundles we gwaha (m2lmaat)elly hya
muscle fibers we el wa7da fehom gwaha myofibrils elly bt3ml contraction.
koooooooooooooool doooooooooooool supported by CONNECTIVE TISSUE
PROPER
TYB DA MT2SM EZAAAAAAY (C.T)
1-elly 7wallen el muscle kolha da 2smo EPIMYSIUM we da byb2a DENSE C.T. ‫ذات‬
‫طبقه كثيفه‬
2-nod5ool gwa 4wya elly 7wallen el BUNDLE(FASCICLE) 2SMOOO PERIMYSIUM
WE DA BYB2A LESS DENSE MN EPIMYSIUM
3-tyb elly 7wallen el muscle fiber el wa7da esmo endomysium >layer of reticular
fibers that surround each muscle fiber
>>>>>c.t. is essential for :force transmission & connecting the muscle fibers
together. it also rich in nerve fibers and blood vessels that nourish the muscle
fibers through diffusion
by5leeehm mtmasken we byb2a mn t7t le fo2 mn endomysium tooooo perimysium
toooo epimysium
pg. 3
Tab e7na fehmna L Skeletal Muscle 3obra 3an a … t3alo nshof el fiber bta3tha
>Skeletal Muscle Fiber (2olna muscle fiber branched (y3ny elongated cell)
Histological structure ( LM )
Size: 10-100 in diameter & markedly variable in length
Shape: cylindrical, non-bramched ( except in face and tongue)
Sarcolemma: ( 2olna en 2y muscle fiber L membrane L 7awlah 2smo sarcolemma)
> separated from surrounding C.T by a basement membrane
Nuclei: lazem ne3raf L 3 sfat dol : 1- multiple (3shan btkon gaya mn Satellite cells
mtgm3a ma3 ba3d fabt3ml cell feha nuclei kteeer) 2- oval 3- peripheral ( y3ny ta7t
L sarcolemma 3la tol)
Sarcoplasm: acidophilic with uniform transverse striation ( L striation msh
mawgoda fe kol muscle bnfs L shakl 3shan 25tlaf tarteb L actin & myosin
filaments) appear clearly in L.S.
>negy LL EM b2A hnla2y L Sarcoplasm feh:
1- Organelles: include:
1. Myofibrils: L muscle fiber mlyana numerous parallel cylindrical fibrils 3la tol
L fiber
2. Sarcoplasmic reticulum: hwa 3obra 3n sER bs well developed 3shan
ytmasha m3 L muscle fiber > highly organized tubular network around the
myofibrils> specialized for Ca++ storage & pump
3. Mitochondria: numerous ( tabe3y l2n L muscle m7taga energy kbera)
>arranged mainly in rows in-between the myofibrils
4. Other organelles: are few
2- Inclusions: include:
1- Myoglobin: O2 binding pigmented protein, provide oxygen for oxidative
reaction
2- Glycogen & lipid granules: found between the myofibrils to provide energy
*Delwa2ty ya shabab 3ndna goz2 gdeed
: :D
w hantklm feeh kda 3an haga esmaha
pg. 4
_ Triad tubular system :
w dah han3rf eno system 3obara 3an 3 tubes kda by7awat aw lafef 7awaleen kol
myofibril w e7na 3rfna foo2 en 7awaleen el myofibrils fe haga esmaha
sarcoplasmic reticulum f homa el etneen (triad tubular system w sacroplasmic
reticulum ) connected b ba3d w bylfo 7awalen el myofibril
_The Triad Consists Of :
* 1) Transvers ( T ) Tubule : formed by invaginations of the sarcolemma in the
sarcoplasm to encircle all myofibrils
#( ya3ny ehh el habal daah b2aa ...!!!! :') :D
boso ma3aya kda awel haga en el Transvers
( T ) tubule de btetkwn men el
en3'lakat bta3et sarcolemma elly fel sarcoplasm 3ashan t7ot el myofibrils *
ba3edan 3an 7war el en3'lakat da :D kont bas 3uza awasaloko en homa bye2flo
3ala ba3d f bye3mlo el tubule de *
* 2) Two Terminal Cisternae of the sacroplasmic reticulum : 2 Wide Tubules of
the sER , on either side of the T Tubule , thus forming a Triad
# (dool ba2a 2 wide tubules kda men el smooth endoplasmic reticulum byetkwno
7awalen aw fel ganben btoo3 el T Tubule f bye3ml haga esmaha el Triad de ya3ny
(3=tri) ya3ny asdo 3 tubes
________________________________________
Function of skeletal Muscle and the Role of the tubular system :
skeletal muscle exhibit voluntary contraction ( controlled by the will ) , except
pharynx ,esophagus &cremasteric muscle are involuntary .
( b ma3na en kol el skeletal muscle voluntary ya3ny n2dr nt7km feha e7na ma3ada
el 3 7agat dool elly homa pharynx , esophagus & cremasteric muscle dool ba2a
skeletal aah bas involuntary .
____________________________________________
rakzoo el 7ta el gaya de mohma shwaya :D
# by2olk ehh ba2a en el " Triad Tubular System "
has a very very very very
very :P *men delwa2ty le emt7an el histology * very important role in muscle
contraction >> t3alo n3rf ehh heya el role de ..;)
contraction proceeeds as follows :
by2olk en T_Tubule brings action potentials into interior of muscle fiber ( daah
ma3nah ehh 3'eer en wazefet el T-Tubule de ehh 3'er enaha btwasal el nerve
impulse le kol fiber gowa el myofibril elly m7awataha
1) the arrival of a nerve impulse to the neuromuscular junction ( etsaal 3adali
3asaby ) triggers the depolarization of the sarcolemma of muscle fiber .
* by2olk hna nafs el kalam elly olnah foo2 en el nerve impulse wesel w na2al el
pg. 5
polarization lel sarcolemma bta3t el muscle fiber
2) Depolarizationis transmitted to the t-tubules into the depth of the muscle fiber
* by2olk en el depolarization wsl lel t-tubules w kaman wsl le kol el muscle fiber
asdo le a5erha ya3ny
3) it stimulates the sarcoplasmic reticulum to rapidly release the calcium ion ( Ca
2+ ) men el (calcium pump ) into the sarcoplasm
* ma3rfsh meen by2olk bas howa by2olk :P :D
by2olk en el t-tubule stimulate (bt7fz ya3ny ) el sarcoplasmic reticulum elly
m5zna feeha el calcium ions enaha tetala3 el ions bsor3a lel sarcoplasm
4) Ca2+ (calium ion ) facilitates the complex sliding of the actin filaments over the
myosin
* hna ba2a by2olk en el calcium bysahel el sliding of actin & myosin filaments over
each other f ye7sl el contraction lel muscle fiber de aw lel motor unit de w masafet
ma ye7sl contraction le de el muscle kolaha btcontract :D :D
# f bzmtko ba2a el Triad Tubular system mohma fel contraction wala la2 ... !! :D :D
ana haseeb damerko elly yegawb 3al soo2al daah :O :P :D
________________________________________________
nd5ol ba2a 3ala klmten kda sahleen :D
* Regeneration of Skeletal Muscle after injury :
Satellite Cells divide to form new skeletal muscle fiber
* 3ashan kda de bto3tbr el stem cells lel skeletal muscle fiber w de mohma awii
btegy kteer MCQ :D
.......QUESTIONSSSSSSS.............
1- WHY MUSCLE FIBERS CALLED THAT ? DUE TO CONTAINING CONTRACTILE
FILAMENTS (ACTIN & MYOSIN)
2-CELL MEMBRANE OF MUSCLE FIBERS CALLED...........&CYTOPLASM
CALLED..........
3-TYPE OF MUSCULAR TISSUE IN FEMALE GENITAL SYSTEM..(SMOOTH
MUSCLE)
pg. 6
4-SITES OF SKELETAL MUSCLE...........
5- PART OF SKELETAL MUSCLE HAS CONTRACTILE FILAMENTS
.......MYOFIBRILS............
6-TYPES OF MUSCLES ACCORDING TO ...........&.............
7-C.T. IS ESSENTIAL FOR :...............
8-THE SHAPE OF SKELETAL MUSCLE IS DESCRIBED TO BE.....................
9- Size of skeletal muscle fiber is markedly ………. In length
10- Shape of skeletal muscle fiber is cylindrical, non-branched ( except in ………. &
………
11-Sarcolemma is attached to the surrounding C.T. (correct)
12-Nucleai: 1-…….. 2-……… 3-………..
13- Sarcoplasm is ……… by LM and show ……………………
14- organelles of skeletal muscle fiber are: 1-……….. 2- ……….. 3- ……
15- Sarcoplasmic reticulum: is specialized for ………………….
16- Mitochondria is …… while other organelles are few
17- Myoglobin is aprotein that provide energy (correct)
18- The Triad Tubular System consists of : 1-.................. , 2-.......................
19- Site of the Tiad Tubular System ....................
20- The Transevers (T) Tubule surrounded by .........................to form a Triad .
21- all skeletal muscles are voluntary except .1-..............,2-.................,3-................
are involuntary.
22-the triad tubular system is characterized by single sarcoplasmic tubule (
correct )
23- triad tubular system has an important role in muscle fiber division or
regeneration ( correct )
24- depolarization stimulate the sarcoplasmic reticulum to rapidly release of the
........................ to the sarcoplasm .
25 _ ............................facilitates the complex sliding of the actin filaments over the
myosin ..
26 -...........cells acts as the stem cells for the muscle fiber
aw * ....................cells divide to form new skeletal muscle fibers .
pg. 7
P.O.C
Site
Size
Shape
Branching
Sarcolemma
Striation
Nuclei
Tubular system
Regeneration
Action
Innervations
Skeletal muscle
Attached to bone
Largest
Cylindrical
Rarely
Thick
Striated
Multiple – peripheral
Triad system
From satellite cells
Voluntary
Motor
Cardiac muscle
The heart wall
Medium sized
Cylindrical
Branched
Very thin
Non-clear striation
Single - central
Diad system
No regeneration
Involuntary
Autonomic
Smooth muscle
Wall of viscera
Smallest
Spindle-shaped
Non-branched
Thin
Non-striated
Single-central
Absent
From pericytes/UMCs
Involuntary
Autonomic
Good luck :D
pg. 8