General Anatomy Module

Dr. Gamal Taha

Assistant Professor of Anatomy & Embryology

Muscles 1
 Lecture objectives

◼ By the end of this session, you should

be able to:

1. The main components forming the

muscular system

2. Properties, arrangements and location of

each of these components
Muscle Tissue and
Organization
Different types of Muscles
When most of us hear the word
◼

“MUSCLE”
We think of the muscles that move the
skeleton.

◼ Over 700 skeletal muscles have been

named and together they form the
muscular system.
 Muscular System

Classification
of Muscles

Skeletal Smooth Cardiac

Muscle Muscle Muscle
 Different Types of Muscles
◼ However, skeletal muscles are not the only
places where muscle tissue is found.

◼ In fact, muscle tissue is distributed almost

everywhere in the body and is responsible for
the movement of materials within and
throughout the body.
 Properties of Muscle Tissue
1. Excitability: When a muscle cell is
stimulated by the nervous system, by
stretching, or by other stimuli in the
environment, leading to muscle contraction.

2. Contractility: Stimulation of muscle cells

generates tension, which may cause the cell
to shorten. This shortening results in either a
pull on bones of the skeleton or the
movement of specific body parts.
 Properties of Muscle Tissue
3. Elasticity: A contracted muscle cell recoils
to its resting length when the applied
tension is removed. Thus, elasticity is not
the muscle’s ability to stretch, but its ability
to return to its original length when tension
is released.

4. Extensibility: A muscle cell must be

capable of extending in length in response
to the contraction of opposing muscle cells.
 Different types of Muscles

◼ Alongside to the Skeletal Muscles, and

according to the presence or absence of
striations and the arrangement of the fibers,
2 other well defined categories emerges to
our notice

◼ Smooth Muscle Fibers

◼ And Cardiac Muscle Fibers

 Three types of muscle

Skeletal Cardiac Smooth

0
 Info About Muscles

◼ Only body tissue able to

contract

◼ Create movement by
flexing and extending
joints

◼ Body energy converters

(many muscle cells contain
many mitochondria)
 Gross Anatomy of Skeletal
Muscle

◼ Muscle: Multiple fascicles

housing many muscle
fibers, connective tissue
coverings, blood vessels,
nerve fibers
Gross Anatomy of Skeletal
Muscle
 Gross Anatomy of Skeletal
Muscle
◼ Muscle Fiber:
Elongated,
multinucleated,
peripherally situated
nuclii, cylindrical fiber
(cell); contains striations.

◼ Strong contraction and

under Voluntary
control.
Gross Anatomy of Skeletal
Muscle
Gross Anatomy of Skeletal
Muscle
 How Skeletal Muscles
Attach !!!
◼ Origin:
A term given to the beginning of a muscle, most
proximal attachment, usually the least mobile end

◼ Insertion:
A term given to the end part of the muscle, most
distal attachment, usually the most mobile end
 Skeletal Muscle Fiber
Organization

Muscles are classified according to the shape

of the muscle fibers from its origin till the
insertion into different types, putting in
consideration the relation with the
longitudinal axis of the muscle itself
 Skeletal Muscle Fiber
Organization
1. Circular Muscles: Fibers are concentrically
arranged around an opening. A circular
muscle is also called a sphincter, because
contraction of the muscle closes off the
opening. Eg. Orbicularis oris
 Skeletal Muscle Fiber
Organization
2. Parallel Muscles:

◼ Fibers run parallel to its long axis.

Each muscle fiber in this type of
skeletal muscle exhibits the
functional characteristics of the
entire parallel muscle.

◼ The muscle fibers are parallel to the

line of pull, fibers are long but their
number is relatively few.

Eg. Rectus abdominus, sartorious

 Skeletal Muscle Fiber
Organization
3. Convergent
Muscles:

Widespread muscle fibers

that converge on a
common attachment site.
Eg. Pectoralis major
 Skeletal Muscle Fiber
Organization
4. Pennate Muscles: their tendons and muscle
fibers resemble a large feather.

◼ Unipennate: All muscle fibers on the same

side of the tendon

◼ Bipennate: Muscle fibers on both sides of

the tendon

◼ Multipennate: Tendon branches within the

muscle
 Skeletal Muscle Fiber
Organization
5. Cruciate :

The muscle fibers

are made up of two
or more planes in
which they run in
different directions
Eg. Sternomastoid
 Muscle classification
◼ Number of Heads or Bellies

1. Biceps—two heads (Biceps brachii)

2. Triceps—three heads (Triceps brachii)

3. Quadriceps—four heads (Quadriceps femoris)

4. Digastric—two bellies (Anteror and posterior)

 How Skeletal Muscles
Attach !!!
◼ By Fleshy Fibers : e.g. popliteus

◼ By Tendon : the tendon is a long fibrous cord. e.g.

Biceps Muscle.

◼ By Raphe : the raphe is a fibrous band separates

flesh muscles from each other e.g. pharyngeal
muscles.

◼ By Aponeurosis : the aponeurosis is a flat fibrous

sheet. e.g. aponeurosis of external abdominal oblique.
 How Skeletal Muscles
Attach !!!

◼ By tendon:

Ex.: Biceps Ms.

 How Skeletal Muscles
Attach !!!

◼ By fleshy fibers:

Ex.: Popliteus Ms.

 How Skeletal Muscles
Attach !!!

◼ By Raphe:

Ex.: pharyngeal
muscles
 How Skeletal Muscles
Attach !!!

◼By
Aponeurosis:
Ex.:
Palmar aponeurosis
 How Skeletal Muscles
Attach !!!
◼ Attached to an
intermediate
tendon: A muscle may
have 2 fleshy bellies &
an intermediate tendon
in between & so the 2
bellies are inserted into
this tendon eg.
Digastric muscle.

◼ Attached to skin: eg.

Facial muscles
 Nerve Supply of Skeletal
Muscles
◼ Nerve supply of the skeletal muscles:

Through mixed somatic nerves containing

sensory, motor and sympathetic
innervation.

The nerve enters the muscle close to its

center on its deep surface.
 Functions of Skeletal Muscle
Tissue
1. Body movement.

2. Maintenance of posture.

3. Temperature regulation.

4. Storage and movement of materials.

5. Support.
 Muscles for Movements

1. The prime movers : are the muscles

that initiate the movement; they are also
called the Agonist.

2. The antagonist : are the muscles that

produce the opposite action of the
agonist.
 Muscles for Movements

3. Synergists: muscles that assist the prime

movers in action and control any
unwanted movement.

4. Fixators : if the prime movers can move

two joints and the movement is not
wanted in one of these joints; the
movement at the unwanted joint is fixed
by the fixators.
 2- Smooth Muscle Fibers
◼ Smooth muscles are found in the walls of all
hollow organs, such as blood vessels, the
stomach, and the intestines, Small in size,
Spindle in shape, (widest at the middle of
the cell and tapered at each end) a single
nucleus, with No Striations (Lack of proper
arrangement between actin and myosin)
having a centrally located nucleus.

◼ They are under Involuntary Control

Smooth Muscle Fibers
 Smooth Muscle Fibers

◼ Because of their unique structure, they are

(Slow, Resistant to fatigue and under
involuntary control), being capable of
stretching much more than skeletal or cardiac
muscle and can maintain steady levels of
contractions for long periods of time

◼ Most of smooth muscle fibers are visceral

muscle tissue, when brought to action
produce a wavelike contraction known as
Peristalsis.
Gross Anatomy of Smooth
Muscle Fibers
 3- Cardiac Muscle

◼ Unique Tissue, this tissue has some of the

characteristics seen in skeletal muscle and
some of those seen in smooth muscle
tissue, creating a unique type of muscular
tissue.
 Cardiac Muscle
◼ Cardiac cells are larger than smooth
muscle cells but smaller than skeletal
muscle cells.

◼ Branched cylindrical fiber, usually with

one or two centrally located nucleus;
intercalated discs join neighboring fibers;
striated
Gross Anatomy of Cardiac
Muscle Fibers
 Cardiac Muscle

◼ Individual muscle cells arranged in thick

bundles within the heart wall.

◼ These cells are striated like skeletal

muscle fibers, but shorter and thicker,
and they have only one or two nuclei.
Cardiac Muscle
 Cardiac Muscle

◼ Cardiac muscle cells are Auto rhythmic,

meaning that the individual cells can
generate a muscle impulse without nervous
stimulation. This feature of cardiac muscle
cells is responsible for our repetitious,
rhythmic heartbeats.

◼ Influenced and controlled with our

Autonomic Nervous system.
In Summary …
In Summary …
In Summary …
◼ For further inquiries PLZ feel free
to contact at any time through
email

gamal.abdelhady@yu.edu.jo
gamal.abdelhady@med.asu.edu.eg