Muscle

1. “Education is not the learning of facts , but
the training of mind to think”
-Albert Einstein

2. STRUCTURE AND PROPERTIES OF SKELETAL MUSCLE ,
CARDIAC MUSCLE AND SMOOTH MUSCLE
APPLICATION AND IMPLICATION OF MUSCULAR SYSTEM IN
NURSING
Presented by – Priyada Das
Roll no. – 053
4th year Bsc nursing
Guided by - Mrs. Jayashree jena
Tutor , SCB College of Nursing
SCBMCH , Cuttack

3. CONTENT
 Introduction of muscle tissue
 Classification of muscle
 Structure of skeletal muscle
*Muscle fibre
* Microscopic structure of myofibril
*Sarcomere
*Contractile element of muscle
*Neuromuscular junction and neuromuscular transmission
 Properties of skeletal muscle
 Structure and properties of cardiac and smooth muscle
 Application and implication of muscular system in nursing

4. INTRODUCTION
Muscle tissue is made up of cells , called ‘myocytes’ or
‘muscle fibres’.
Study of muscles is celled ‘MYOLOGY’.
Muscle tissue is composed of cells that are specialized
to shorten in length by contraction . This contraction
result in movement.

5. CLASSIFICATION OF MUSCLE
There are about 600 muscles in the human body .
But according to structure and function the 3 main
types of muscle include – 1) Skeletal muscle
2)Cardiac muscle
3)Smooth muscle
In spite of functional diversity some basic similar
features are there for these 3 muscles . For example –
excitability , contractibility , extensibility , elasticity .

6. SKELETAL MUSCLE
Because of its close relation to the bony skeleton it is
called skeletal muscle .
When examined under microscope fibers of skeletal
muscle shows prominent transverse striations .
Therefore they are also called ‘striated muscle’ .
Skeletal muscle can normally be made to contract
under our will , to perform movement we desire . It is
therefore called ‘voluntary muscle’.

7. MUSCLE FIBRES
Muscle fibres consists of single elongated muscle
cells.
Each fibre is surrounded by a cell membrane called
‘SARCOLEMMA’. (plasma membrane of muscle cell).
The cytoplasm is called ‘SARCOPLASM’ , which is
rich in mitochondria and bundles of fine
longitudinal threads called myofibrils.

8. MICROSCOPIC STRUCTURE OF MYOFIBRIL
Light microscopic studies shows that , each
myofibril consists of a number of two alternating
bands . The two bands are –
A. Light band or ‘I’ band
B. Dark band or ‘A’ band

9. LIGHT BAND
The light band is called ‘I’ band because it is isotropic
to polarised light .
‘I’ band is divided into two portions by a narrow dark
line , called ‘Z’ line (Z= zwischenscheibe =between
disks )
‘Z’ line is formed by a protein disk which does not
permit passage of light.
The portion of myofibril in between two ‘Z’ line is
called ‘SARCOMERE’

10. DARK BAND
The dark band is called ‘A’ band because it is anisotropic
to polarised light .
In a intact muscle fibre ‘I’ band and ‘A’ band of the
adjacent myofibril are placed side by side .It gives
appearance of characterstic cross striations in the muscle
fibre .
In the middle of ‘A’ band there is a light area called ‘H’
zone (H= hell = light in germen , H= Hansen – discoverer
)
In the middle of ‘H’ zone , lies the middle part of myosin

13. SARCOMERE
The portion of myofibril that lies between two
successive z-line is known as the ‘Sarcomere’
Sarcomere is the structural and functional unit of
muscle fibre .
When the muscle contract Z-line moves close
together and length of each sarcomere decreases .

14. CONTRACTILE ELEMENT OF MUSCLE
Myofibrils are the contractile units of muscle fibre
Under electron microscope each myofibril is composed
of still smaller units , that is the thick and thin
myofilaments
The thick myofilaments are ‘MYOSIN’ and is situated in
‘A’ band .
They are composed of protein called ‘MYOSIN’
Thin filaments are “ACTINE” filament extend from the
either side of Z-line , runs across ‘I’ band and enter into

15. NEUROMUSCULAR JUNCTION
Each skeletal muscle is innervated by one or more nerves
containing both sensory and motor nerve fibres.
After entering into muscles , the nerve divided into
branches to supply muscle fibres.
The junction between the motor nerve and the skeletal
muscle fibre is called ‘neuromuscular junction’ or
‘myoneural junction’ .
Terminal branch of nerve fibre is called axon terminal.
The axon terminal contains mitochondria and synaptic

16. CONT.
The synaptic vesicles contains the neurotransmitter
substances , acetylcholine .
The acetylcholine is synthesized by the mitochondria
present in the axon terminals and stored in the vesicles.
The membrane in the nerve ending is called ‘presynaptic
membrane’. The membrane of the muscle fibre is called
‘postsynaptic membrane’.
The space between these two membrane is called
‘synaptic cleft’ . The synaptic cleft contain enzyme called
‘acetylcholinesterase’ .

18. NEUROMUSCULAR TRANSMISSION
When the muscle cell is stimulated , electrical changes
occur which are collectively called ‘action potential’ .
When the action potential reaches the nerve terminal , the
presynaptic membrane become highly permeable to ca2+
Large amount of ca2+enter into synaptic cleft . This
ca2+causes release of acetylcholine into the synaptic cleft
.
The Ach binds with nicotinic receptors present in
postsynaptic membrane , which in tern initiate muscle
contraction .

20. PROPERTIES OF SKELETAL MUSCLE
1)Excitability : It is defined as the reaction or response of
tissue to irritation and stimulation.
2)Contractility : It is the response of the skeletal muscle by
chance in either the length and tension of the muscle fibre.
3)Muscle tone : It plays an important role in maintenance of
posture . Changes in muscle tone enables movement of
different part of the body .
4) Extensibility : It is the ability of the muscle to extend when
it is stretched.

21. CARDIAC MUSCLE
It is present exclusively in heart and in the
beginning of large vessels arising from it.
It is involuntary and striated ; It has inherited
rhythmic contractibility .
Cardiac muscle or the myocardium form the
musculature of heart.

22. STRUCTURE OF CARDIAC MUSCLE
The fibres of cardiac muscle do not run in strict parallel
formation , but branch and anastomose with other fibre
to form a network .
Each fibre of cardiac muscle is not multinucleated
syncytium as in skeletal muscle , but it is a chain of
cardiac muscle cell , each having it’s own nucleus .
Nucleus of each myocytes is located centrally (and not
peripherally as in skeletal muscle.
The sarcoplasm of cardiac myocytes is abundant and
contains numerus large mitochondria.

23. CONT.
The myofibrils are relatively few . At places the myofibrils
merge with each other.
As a result of these factors , the myofibrils and striations of
cardiac muscle are not as distinct as those of skeletal muscle
.
With the light microscope the junction between the adjoining
cardiac myocytes are seen as dark staining transverse lines
running across the muscle fibre . These lines are called
‘intercalated disk’ .
Sometimes , the discs do not run straight across the fibres ,

24. CONT.
Gap junctions allows direct communication between
the cardiac myocytes by connecting cytoplasm of the
cells . It relay electrical impulses from the one cardiac
myocytes to another and help in cell-to-cell
conduction .
Cardiac muscle cells are connected end to end by
structure known as intercalated disc . These are
irregular transverse thickening of sarcolemma , within
which there are desmosomes , that hold the cells

26. PROPERTIES OF CARDIAC MUSCLE
1)Automaticity : It means the ability of the cells –
-To initiate it’s beat continuously without external
stimulation .
- To undergo depolarization (forming of action
potential) spontaneously causing the production of
electrical impulses.
2)Rhythmicity : Rhythmicity means that-
-Contraction of heart at regular interval without
external stimuli.

27. CONT.
3)Excitability : It is the ability of cardiac cell to initiate
action potential in response to inward depolarization
current.
4)Conductivity : It is the ability to propagate an impulse
i.e. from SA node to all cardiac muscle fibre.
5)Contractibility : Cardiac muscle contracts in response
to the electrical impulse generated by the SA Node.
ALL OR NONE RESPONSE : Heart is a functional
syncytium . Therefore all it’s fibres act as a single fibre
. Heart either does not contract at all or it contract with

28. SMOOTH MUSCLE
Smooth muscle also called involuntary muscle , nonstriated
(muscle that shows no cross strips under microscopic
magnification) or plain muscle .
It is made up of long spindle shaped cells (myocytes)
having broad central part and tapering ends.
The nucleus , which is oval or elongated lies in the central
part of the cell.
The length of the smooth muscle is highly variable.
With the light microscope , the sarcoplasm do not have

29. CONT.
The dense bodies and the intermediate filaments are
networked through the sarcoplasm which cause the muscle
fibre to contract.
The actin filaments are attached to the dense bodies
Dense bodies appear darker under an electron microscope
and so they are sometimes described as electron dense.
The intermediate filaments are connected to the
intermediate filaments via dense bodies.
Smooth muscles can be classified into 2 types
1)single unit smooth muscle
2)multi unit smooth muscle

31. SINGLE UNIT SMOOTH MUSCLE V/S MULTI UNIT SMOOTH
MUSCLE
Single unit smooth muscle
Each smooth muscle cells
combine , attach to each other
and act in a whole.
It is found in walls of the
visceral organ so called visceral
muscle .
e.g. wall of stomach , kidney ,
uterus , esophagus etc.(except
heart)
The cells possesses gap
junctions and contraction
Multi unit smooth muscle
Each smooth muscle
receive it’s synaptic input .
So it has much finer
control.
It is found in trachea ,
large arteries and ciliary
muscle of eye.
It don’t possesses gap
junction and contraction

32. CONT.
Single unit muscle cells
The muscle cells function
collectively and
simultaneously as a single
unit.
Multi unit muscle cells
The muscle cells can not
function collectively and
work independently.

34. PROPERTIES OF SMOOTH MUSCLE
1)Plasticity : Relationship between initial length of muscle
fiber and tension . Unique ability to adopt easily and
quickly to length changes without compromising it’s
ability to generate force.
2)Contractility : It stimulates the contractility of the
digestive , urinary , reproductive system , bladder and
airway.
3)Excitability

35. BRIEF DESCRIPTION OF SKELETAL , SMOOTH AND CARDIAC
MUSCLE
Characterstic
s
Skeletal
muscle
Cardiac
muscle
Smooth
muscle
Location Limbs and trunk myocardium Hollow vicera and
blood vessels
Shape and
arrangement of
fibers
Elongated and
parallel fibers
Parallel fibers
with branching
and anastomosis
Elongated and
fusiform , spindle
shaped.
Transverse
striations
present Present absent
Nucleus Multinucleated
and peripherally
located
Single nucleus
and centrally
located
Single nucleus
and centrally
located

36. CONT.
characterstics Skeletal muscle Cardiac muscle Smooth muscle
Sarcoplasmic
reticulum
Complex and
very well
developed
Less well
developed
Poorly
developed
Nerve supply Somatic Autonomic
nervous
system
Autonomic
nervous
system
contraction Powerful and
voluntary
Powerful ,
constant and
involuntary
Slow ,
involuntary
and rhythmic

38. APPLICATION AND IMPLICATION IN NURSING
The muscular system enables body movements , joint
stabilization and maintenance of posture .
It is important for the practicing nurse to have a
knowledge of principles of body mechanics and the skill
required to use that knowledge .
One can save energy and prevent muscle strains by
avoiding the use of small muscles of the back and
flexing the knees (using the strong muscles of thigh
and buttocks )while lifting an object from the floor or

39. CONT.
• The knowledge of muscular system helps the nursing
professional in performing his /her duties with ease and
understanding in all patient of all age groups.
• In the newborn , a nurse can examine the muscle tone .
• In an adult patient the main problem associated with
musculoskeletal system are pain and limited mobility.
• It is important for the nurse to judge the degree of
muscle power as passive , active and against resistance
and accordingly give exercise (physiotherapy ) to the
patient.

40. CONT.
• The knowledge of muscular system also help the nurse to
understand the pathophysiology of disease , assess the disease
perfectly , diagnose the case properly and to plan and
implementation of effective care.
• Diseases affecting muscular system are –
-myasthenia gravis
-myositis
-wasting and atrophy of muscles
-hypertrophy and hyperplasia
-fasciculation and fibrillation

41. MYASTHENIA GRAVIS

42. FASCICULATION

43. MUSCLE ATROPHY /DYSTROPHY

44. HYPERTROPHY AND HYPERPLASIA

45. MYOSITIS

46. CONCLUSION
• Muscle is an excitable tissue , responsible for most of
our functions like –locomotion , posture , speech ,
respiration , pumping of blood , movement of food ,
expulsion of wastes etc.
• So muscle is a highly diverse tissue which can perform
a great variety of function.

47. SUMMARY
This topic include – introduction of muscle tissue ,
classification of muscle , definition of muscle fibre,
microscopic structure of myofibril , sarcomere ,
contractile element of muscle , neuromuscular
junction and neuromuscular transmission , structure
and properties of cardiac and smooth muscle ,
application and implication of muscular system in
nursing .

48. ANY QUERIES…..?

49. BIBLIOGRAPHY
Ashalata “Textbook of anatomy and physiology for nurses” , 4th
edition , jaypee publication , unit-1 , page –198-207
Ross and wilson “Anatomy and physiology in health and illness”
, 14th edition , Elsevier publication , unit -1 , page – 44,45
Wolters Kluwer “Anatomy and physiology for nursing and health
care students” ,4th edition , unit – 1 , page –125 to 130
https://www.slideshsre.net/skeletalmuscle
https://www.slideshare.net/cardiac-muscle-physiology
https://www.slideshare.net/smoothmuscle

50. QUESTION AND ANSWER SESSION
1) Muscle tissue is made up of cells , that are called
2) Skeletal muscle is otherwise called
3) What are the contractile unit of muscle fibre ?
4) Where cardiac muscle is located ?
5) What is gap junction ?
6) How the nucleus of skeletal muscle is differ from
cardiac muscle?
7) Why muscular system is important in nursing ?
8) Why light band is called ‘I’ band ?

51. ASSIGNMENT
1. Write down the structure and properties of skeletal
muscle .
2. What is neuromuscular junction ? Write down about
neuromuscular transmission .
3. Describe the application and implication of
muscular system in nursing .