THE MUSCLE THE MUSCLE TISSUE TISSUE

Dr. Samar AskerDr. Samar Asker

Dr. Samar AskerDr. Samar Asker

  Skeletal Cardiac SmoothSite: skeleton  heart visceraSize: Largest Medium   Smallest Shape  cylindrical  Cylindrical Fusiform Sarcomere Regular ↓ regular Absent Sarcolemma thick very thin  Thin Striation Distinct  less distinct Non 

Satellite cells Present   Absent  Absent

  Skeletal Cardiac SmoothNuclei: Peripheral, 

multiple, ovalcentral, single,

oval

central, single, oval

Cell  Junction absent Intercalary discs

Gap Junction

Regeneration Satellite cells no regeneration 

pericytes & U.M.C. mitosis

Tubular sys Triad Diad Absent

Origin: Myoblast Myoblast U.M.C.

Nerve suppl Somatic  Autonomic Autonomic

THE NERVOUS THE NERVOUS TISSUETISSUE

Dr. Samar Asker

Dr. Samar Asker

THE NEURON

Dr. Samar Asker

Structural and functional unit

consists of:

Cell body

Nucleus cytoplasm.Processes: dendrites and axon.

Dr. Samar Asker

THE CELL BODYTHE CELL BODY

The nucleusThe nucleus:: Large, rounded, Large, rounded,

usually central usually central and vesicular and vesicular with a with a prominent prominent nucleolus. nucleolus.

The cytoplasmThe cytoplasm: : OrganellesOrganelles::

Nissl granulesNissl granules Neurofibrils Neurofibrils Golgi Golgi

apparatus apparatus Mitochondria Mitochondria

Centrioles is Centrioles is

absent absent

b- Inclusionsb- Inclusions: : * Melanin * Melanin

pigments:pigments: in in some nerve some nerve cells cells

eg. cells of eg. cells of substania substania nigra. nigra.

* Lipofuscin * Lipofuscin pigmentspigments: : yellow yellow pigments pigments increase in old increase in old age. age.

* Glycogen * Glycogen granules. granules.

* Fat droplets. * Fat droplets.

Dr. Samar Asker

PRO

CES

SES

PRO

CES

SES

The axon The dendrites

Number: Single. Numerous

Thick& Length:

Thin & long.

Thick & short.

Diameter:

It has a constant diameter along its length.

decrease gradually towards their ends i.e. tapering.

The axon The dendrites

Contour: Smooth. Irregular.

Branching: at its terminal end only i.e.but it may give collateral branches which arise at right angles. No spines

give extensive branching like a tree .The branches arise at acute angles and may show spines.

Content: Contains mitochondria

and neurofibrils

only (no Nissl granules).

Contain neurofibrils and Nissl granules.

The axon dendrites

Conduction of nerve impulses:

away from the cell body

to the cell body

Dr. Samar Asker

Classification of the neuronsClassification of the neuronsAccording to the number of processes (Polarity): Unipolar nerve cells: Nerve cells are rounded with only one process. Site: spinal ganglia mesencephalic nucleus of the trigeminal nerve.

Dr. Samar Asker

Bipolar nerve cells:Bipolar nerve cells:

with 2 processes, a with 2 processes, a dendrite and an dendrite and an axon.axon.

Retina of the eye. Retina of the eye. Cochlear and Cochlear and

vestibular ganglia vestibular ganglia in the ear.in the ear.

Olfactory Olfactory epithelium of the epithelium of the nose. nose.

Multipolar nerve cells: Multipolar nerve cells: Have many dendrites Have many dendrites

and one axon. and one axon. stellate :stellate :- Anterior horn cells of the - Anterior horn cells of the

spinal cord. spinal cord. Pyramidal: Pyramidal: cerebral cortex. cerebral cortex. Pyriform:Pyriform: Purkinje cells Purkinje cells

of the cerebellumof the cerebellum

NERVE GANGLIACollection of nerve cells and fibers, outside the C. N. S. They are sensory (spinal) & autonomic (sympathetic ganglia)

Spinal Sympathetic1. Thick CT capsule .

2. Unipolar cells.3. Variable Size4. poor blood vessels 5. Large cells 6. Arranged in groups or

rows.7. Glomerulus: Present8. large number of satellite

cells

9. Myelinated nerve fibers .10. No synapse () cells

Thin.

Stellate Multipolar

uniform size.

Rich.

Smaller

Scattered

Absent

Few satellite cells

non myelinated

Synapse present

practical

L.S in skeletal muscle

T.S in skeletal muscle

Nerve trunk

Spinal ganglia