General histology

1. GENERAL HISTOLOGY
DR SAMINA SHAHEEN
ASSISTANT PROFESSOR OF ANATOMY
KEMU

2. BASIC TISSUES
Epithelium
Connective tissue
Muscular tissue
Nervous tissue

3. Organs divided into:
Parenchyma –cells
Stroma –supporting tissue

4. SIMPLE SQUAMOUS EPITHELIUM
Composed of very thin flat
irregular shaped cell that form
a continuous surface
Also called pavement
epithelium
Found in:
Lining of blood & lymph
vessels
Alveoli of lungs
Parietal layer of Bowman’s
capsule
Loop of Henle in kidney

5. SIMPLE CUBOIDAL EPITHELIUM
Cells appear cube or box like
Nucleus is rounded & placed in
centre of cell
 cells rest on basement
membrane
Present in:
Follicles of thyroid gland
Distal convoluted tubules of kidney
FUNCTION
Absorption
excretion

6. SIMPLE COLUMNAR NON
CILIATED EPITHELUIUM
Composed of tall columnar
cells
Rests on basement
membrane
Nucleus in elongated & lies
in basal half of cell
Apical surface of cells may
have microvilli which give
apperance of brush border
Found in:
Lining of GIT
FUNCTIONS:
Absorption
Excretion

7. SIMPLE COLUMNAR CILIATED
EPITHELIUM
CILIA present on surface of
simple columnar epithelium
Present in:
Small intrapulmonary bronchi
Simple columnar non-ciliated
cells may be present between
ciliated cells
Example :
Uterine tube
Efferent ductules of testis

8. PSEUDOSTRATIEIED EPITHELIUM
NON-CILIATED
Variant of simple columnar
epithelium
Tall & short cells are present
All cells rest on basement
membrane
Nuclei disposed at different
levels
Present in;
Parts of male urethra

9. PSEUDOSTRATIEIED EPITHELIUM
CILIATED
This epithelium
may be ciliate with
goblet cells
Example:
Trachea
Larger bronchi

11. STRATIFIED EPITHELIA
STRATIFIED SQUAMOUS NON
KERATINIZEXEPITHELIUM
Multi-layered
Basal layer low columnar or high
cuboidal
This layer divides
Subsequent layers polygonal
Surface layers flattened
Underlying connective tissue raised
into ridges
Examples :
Oesophagus
Anal canal
Cervix
Vagina

12. STRATIFIED SQUAMOUS
KERATINIZED EPITHELIUM
Features same as
non-keratinized
epithelium except
Surface layer
composed of non-
nucleated cells
They acquire
protein keratin
Example :
Skin

13. TRANSITIONAL EPITHELIUM
IN RELAXED STATE
Is 4-5 cell layer thick
Basal layer is cuboidal
Intermediate layer is
polyhedral
surface layer is cuboidal
with binucleate cells
IN STRETCHED STATE
Is 2-3 cell thick
Surface layer is squamous
Example :
 urinary tract

14. STRATIFIED CUBOIDAL
Consists of two
layers of cuboidal
cells
Cells of superficial
layer are smaller
Examples :
Ducts of salivary
glands
Ducts of sweat
glands

16. STRATIFIED COLUMNAR EPITHELIUM
Basal layer consists of low columnar or cuboidal cells
Surface layer is of tall columnar cells
Examples :
Conjunctiva
Parts of male urethra
ENDOTHELIUM
Lines all blood & lymph channels
MESOTHELIUM
Lining of pleura, pericardium & peritoneum

17. CONNECTIVE TISSUE
Characterized by the presence of relatively few cells & abundant
intercellular substance
FUNCTIONS
STRUCTURE
Cells
Fibres
Ground substance
Develops from MESENCHYME

18. CELLS OF CONNECTIVE
TISSUE
Fibroblasts
Mast cells
Plasma cells
Macrophages (histiocytes)
Leukocytes
Adipocytes

19. MESENCHYMAL CELLS

20. FIBROBLASTS

21. MACROPHAGES

22. PLASMA CELLS

23. MAST CELLS

24. ADIPOCYTES

25. FIBERS OF CONNECTIVE
TISSUE
Collagen
Elastic
Reticular

26. COLLAGEN FIBERS

27. ELASTIC FIBERS

28. RETICULAR FIBRES

29. GROUND SUBSTANCE
Glycosaminoglycans (mucopolysaccharides)
Proteoglycans
Multiadhesive glycoproteins

30. TYPES OF CONNECTIVE
TISSUE
Embryonic connective tissue
Mesenchyme
Mucous
Adult connective tissue
Connective tissue proper
Loose
Dense

Irregular

Regular
Specialized

Reticular

Adipose
Bone
Cartilage

31. LOOSE CONNECTIVE TISSUE &
DENSE IRREGULAR CONNECTIVE
TISSUE

32. DENSE REGULAR CONNECTIVE
TISSUE

33. RETICULAR TISSUE

34. EMBRYONIC CONNECTIVE TISSUE
MESENCHYME MUCOUS

35. CARTILAGE
Cells (chondrocytes)
Extra-cellular matrix
Fibrils
Ground substance

Proterglycan

Glycosaminoglycanp (mucopolysaccharide)

36. TYPES OF CARTILAGE
Hyaline
Elastic
Fiibrocartilage

37. HYALINE CARTILAGE

38. ELASTIC CARTILAGE

39. FIBROCARTILAGE

40. BONE
Cells
Osteocytes
Osteoblasts
Osteoclasts
Bone matrix
Organic

Collagen type 1

Ground substance
Proteoglycans
Glycoproteins
Inorganic

Hydroxyapatite

Ca Po4, magnesium, bicarbonate, citrate, sodium & potassium

41. TYPES OF BONE
(GROSS OBSERVATION)

43. TYPES OF BONE
(MICROSCOPIC EXAMINATION)
PRIMARY/IMMATURE BONE SECONDARY/ MATURE

44. MUSCLE
Skeletal muscle
Smooth muscle
Cardiac muscle

45. ORGANIAZATION OF SKELETAL
MUSCLE
Endomysium – muscle fiber
Perimysium – fascile
Epimysium – entire muscle

46. ORGANIZATION OF SKELETAL
MUSCLE

47. SKELETAL MUSCLE

48. CARDIAC MUSCLE

49. CARDIAC MUSCLE

50. SMOOTH MUSCLE

51. SMOOTH MUSCLE

52. COMPARISON BETWEEN THE THREE
TYPES OF MUSCLES

53. NERVE TISSUE & NERVOUS
SYSTEM
Central nervous system
Brain & spinal cord
Peripheral nervous system
Spinal, cranial & peripheral nerves
ganglia
Nerve cells (neuron)
Glial cell (supporting cells)

54. STRUCTURE OF NEURON
Cell body
Axon
dendrite

55. GLIAL CELLS
CNS
Oligodendrocytes
Ependymal cells
Astrocytes
Microglial cells
PNS
Neurolemmocytes
(Schwann cells)
Saltellite cells

56. PERIPHERAL NERVOUS
SYSTEM
COMPONENTS OF PNS
•Nerves
•Ganglia
•Nerve endings.
CONNECTIVE TISSUE COMPONENTS OF A
PERIPHERAL NERVE:
•Endoneurium: constitues the loose c.t associated
with individual nerve fiber. It merges with an
external lamina of IV collagen ,laminin and other
proteins produced by schwann cells. Other cells
are fibroblasts and mast cells.

57. •Perineurium is a specialized
c.tissue surrounding a nerve
fascicle. It serves as a
metabolically active diffusion
barrier that contribute to the
formation of blood –nerve
barrier. It may be one or two
cell thick depending on the
nerve diameter .It is formed by
layers of flattened epithelial
cells. The cells of each layer of
the perineurium are joined at
their edges by tight junctions
•Epineurium consists of dense
irregular c .tissue that surround
and binds nerve fascicles into
a common bundle. Blood
vessels that supply the nerve
travel in epineurium.

58. GANGLIA
•It is an ovoid structures
contain neuronal cell bodies
and glial cells supported by
c.tissue.
•Serves as relay stations to
transmit nerve impulses.
Types of ganglia:
•Sensory ganglia: They
receive afferent impulses
that go to the CNS. They
are associated with cranial
nerves called cranial
ganglia, and the dorsal root
of spinal nerves called
spinal ganglia

59. continued….
•Connective tissue capsule which is continuous with the
epineurium of nerve on which ganglion is situated Ganglion
cells are neurons of pseudounipolar type. Each neuron
gives rise to a single process which makes several irregular
turns around the cell body and bifurcate in a T- shaped
manner. One branch acts as dendrite and pass in a spinal or
cranial nerve to periphery and terminate at a receptor and
other branch act as functional axon and passes to CNS. Size
of nerve cell body varies. Small cell bodies give rise to
unmyelinated processes, large perikarya give origin to
myelinated processes. Nerve cell bodies are arranged as
groups in peripheral zone of ganglion and surrounded by a
single layer of low cuboidal cells called satellite cells. The
central zone is devoid of nerve cell bodies and contain nerve
fibers.

60. AUTONOMIC GANGLIA
• They are associated with
sympathetic and parasympathetic
division of autonomic nervous
system.
•Arranged as small bulbous
dilatations in autonomic nerves.
•Located in certain organs
especially in the wall of GIT called
intrameural ganglia.
•Covered by less well developed c.
tissue capsule.
•Multipolar neuron which are
evenly distributed.
•Covered by a layer of satellite
cells.
•Parasympathetic ganglia lacks
distinct capsule, perikarya and
associated satellite cells form a
loosely organized plexus within
the surrounding c .tissue.

61. STRUCTURE OF THE
CEREBRAL CORTEX
The cerebral cortex
forms a complete
covering of the cerebral
hemisphere. It is
composed of gray
matter and contains
approx. 10 million
neurons. The gray
matter contains nerve
cells, neuroglia and
blood vessels. The
following types of nerve
cells are present in the
cerebral cortex:
Pyramidal cells
Nonpyramidal cells

62. PYRAMIDAL CELLS
Contains a large vesicular
nucleus
Abundant nissl granules
One main dendrite arises
from the apex and ends in
the most superficial layer of
the cortex.
Four or more branching
dendrite pass outward from
the base of the perikaryon.
Axon emerges from the
center of the base and runs
into the underlying white
matter.
Classified into small,
medium and large varieties.

63. Nonpyramidal cells
Stellate/granule cells: small polygonal
perikaryon; each cell gives off a number of small
dendrites passing in various direction and a short
axon which ramifies close to the cell body; most of
the extrinsic inputs to the cerebral cortex terminate
on the dendrites of the stellate cells.
Horizontal cells of cajal: small, fusiformed,
horizontally oriented; found in the most superficial
cortical layer; has many short dendrites and a long
axon which runs parallel to the surface of the cortex
making contact with the dendrites of the pyramidal
cells.

64. CONTINUED
Martinotti cells: small, multipolar cells found in
the deeper layers of the cerebral cortex; has a
short dendrite but the long axon ascends towards
the cortical surface to end in a more superficial
layer.
 Fusiform cells. They have long axis vertical to
the surface and concentrated mainly in the deeper
cortical layers.Dendrites arise from each pole of
the cell body and ascend toward the surface of the
surface of the cortex and branch in the superfical
layers. The axon arises from the inferior pole of
cell body and enter the white matter as a
projection ,association or commissural fiber.

65. LAYERS OF THE CEREBRAL
CORTEX
Molecular or Plexiform Layer:
composed chiefly of cell processes (of the
cells lying in the deeper layers). Some
horizontal cells are also present.
External Granular Layer: contains
large number of small pyramidal cells and
numerous closely packed stellate cells.
Pyramidal Cell Layer: also known as
external pyramidal layer and is composed
mainly of large pyramidal cells. some
granule cells are also present.

66. Internal Granular Layer: consists of
closely packed stellate cells. There is a
high concentration of horizontally
arranged nerve fibers known as outer
band of Baillarger.
Ganglionic Layer: also known as
internal pyramidal layer contains large
pyramidal cells. Scattered among the
pyramidal cells are stellate and martinotti
cells. This layer also contains a large
number of nerve fibers which forms the
inner band of Baillarger.

67. Multiform Layer:
composed of neurons
of many shapes. Also
contains pyramidal
cells, stellate cells
and martinotti
cells.Many nerve
fibers are also
present that are
entering or are
leaving the underlying
white matter.

68. All areas of cerebral cortex do not possess six layers.
They are called as heterotypical as compared to
majority which are homotypical and possess six
layers.
Two heterotypical areas are the granular type and the
agranular type.
In the granular type layer 2 and 4 are well developed
and layer 3 and 5 are poorly developed. It is found in
postcentral gyrus.
In agranular type layer 2 and 4 are absent, pyramidal
cells in layer 3 and 5 are densely packed and are very
large . It is found in precentral gyrus. These areas are
associated with motor functions.

69. CEREBELLUM
Cerebellum is
composed of an outer
covering of gray
matter called cortex
and inner white
matter. Embedded in
the white matter of
each hemisphere are
three masses of gray
matter forming
intracerebellar nuclei.

70. STRUCTURE OF
CEREBELLIUM
The cerebellar cortex on section shows
three layers from within outwards.
Molecular layer: This layer contains two
types of neurons, the outer stellate cells
and inner basket cells. These neurons are
scattered among dendritic arborizations
and numerous thin axons that run parallel
to the long axis of the folia. Neuroglial
cells are found between these structures.

71. The Stellate cells have small star- shaped perikarya.Each cell
has many short thin dendrites and a fini unmyelinated axon.The
dendrites ramify near the cell body,while the axon extends
tranversely to make synapses with the dendrites of Purkinje
cells.
The Basket cells have small perikarya which give rise to
numerous branching dendrites that ascends towards the
surface. The unmyelinated axons of the basket cell runs
horizontally,along its course it gives off many descending
branches which form basket like terminal arborization around
the bodies of the Purkinje cells.

72. PURKINJE CELL LAYER
The Purkinje cells are large Golgi type l
neurons they are flask shaped and are
arranged in a single layer. In a plane
transverse to the folium ,the dendrites
pass into the molecular layer, where they
undergo profuse branching. The primary
and secondary branches are smooth and
subsequent branches are covered by
short thick dendritic spines.Spine form
synaptic contacts with the parallel fibers
derived from the granule cell axons.
At the base of thePurkinje cells, the
axons arises and passes through the
granular layer to enter the white matter.
On entering the white matter, the axons
acquires a myelin sheath, and it
terminates by synapsing with cells of one
of the intracerebellar nuclei .Collateral
branches make synaptic contact with the
dendrites of basket and stellate cells of
the granular layer in the same area or in
distal folia. A few Purkinje cell axons
pass directly to end in the vestibular
nuclei of the brainstem.

73. GRANULAR LAYER
Small granule cells with dark staining nucleous with very
little cytoplasm.
Also present in this layer are Golgi type II cells with
vesicular nucleous and abundant cytoplasm
Clear spaces called glomeruli are present in this layer
Each granule cell give rise to four to five short dendrites
.The unmyelinated axon of agranule cell ascend to
the molecular layer where it bifurcate into two
branches and called parallel fibers .Thesefibers
make synapses with dendrites of purkinje cells. .

74. AFFERENT FIBERS OF
CEREBELLUM
Climbing fibers .They originate from
inferior olivery nucleus of
m.oblongata.Asthey enter in cerebllum
they run in white matter and then
synapse with dendrites of purkinje cell
in molecular layer.
Mossy fibers .They originates in spinal
cord and terminate in glomeruli of
cerebellar cortex where they synapse
with dendrites of granule cells and
axons of golgi type11 cells

75. CEREBELLUM

76. CEREBELLUM

77. SENSORY NERVE ENDINGS
OR RECEPTORS
•Morphologically divided into:
•Non –encapsulated or free nerve endings
•Encapsulated nerve endings
•Free nerve endings
•Afferent fibers are myelinated or unmyelinated
•Specialized to respond to sensation of pain, temperature
or light touch.
•In epidermis of skin they form disc like endings with
modified epithelial cells called Merkel corpuscle.
•Function as mechanoreceptors, detecting mechanical
displacement of skin.

78. ENCAPSULATED NERVE
ENDINGS
Tactile corpuscles of meissner:
•Located in non hairy skin especially finger tips,
palm and soles, lips and nipples.
•Oval bodies covered by c.t capsule continuous
with epineurim of nerve supplying the corpuscle
which contain multilayered flattened cells.
•Myelinated nerve fibers supply each corpuscle.
•They are concerned with perception of touch
sensation.

79. RUFFINIS ENDINGS
Fusiform struture 1-2mmin length and
present in skin in joint capsule.
Consist of thin c.tissue capsule
containing a fluid filled space.
A single myelinated nerve supply it .
Function as mechanoreceptor.

80. END BULB OF KRAUSE
They are spherical bodies covered by a
c.tissue capsule and contain a central
cavity.
A myelinated nerve supply it.
Concerned with perception of cold
sensation
Present in skin.

81. MUSCLE SPINDLES
•Present in skeletal
muscle.
•Fusiform structure,0.5-
5mm in length.
•Consist of intrafusal fibers
and covered by a capsule.
•Supplied by both afferent
and efferent fibers.
•Concerned with regulation
of reflex muscle tone.

82. TENDON ORGANS OF
GOLGI
Located in tendons close to muscle
tendon junction.
Consist of small bundle of collagen
fibers covered by a c.tissue capsule.
A large myelinated nerve enter the
organ.
They respond to an increase in muscle
tension.

83. NERVE FIBERS

84. PERIPHERAL NERVE
Endoneurium
Perineurium
epineurium

85. CIRCULATORY SYSTEM
Heart
Arteries
capillaries
Veins

86. 23-86
Blood Vessel Tunics
Tunica Intima, or Tunica Interna
innermost layer
composed of:

an endothelium (simple squamous epithelium)

subendothelial layer (areolar CT)
Tunica Media
middle layer of the vessel wall
composed of:

circularly arranged smooth muscle cells
Sympathetic innervation:

Increase: vasoconstriction (narrowing of the blood vessel
lumen)

Decrease: vasodilation (widening of the blood vessel lumen)

87. 23-87
Blood Vessel Tunics
Tunica Externa, or Tunica Adventitia
outermost layer
composed of:

areolar connective tissue that contains elastic and collagen fibers
helps anchor the vessel to other tissues
Term adventitia is used to specify outer layer in blood vessels that
are buried in CT
Vasa vasorum : blood vessels that supply large blood vessels
In the externa
Arteries vs Veins:
Media largest in arteries, externa largest in veins
Lumen is smallest in arteries
Artery wall have more elastic and collagen fibers
Capillaries: only the Interna

88. 88

89. 23-89
Arteries
In the systemic circulation, carry oxygenated
blood to the body tissues.
Pulmonary arteries carry deoxygenated blood
to the lungs.
Three basic types of arteries:
elastic arteries, muscular arteries, and arterioles
as an artery’s diameter decreases

corresponding decrease in the amount of elastic fibers

relative increase in the amount of smooth muscle

90. 90

91. 23-91
Capillaries
Contain only the tunica intima, but this layer consists
of a basement membrane and endothelium only.
Allow gas and nutrient exchange between the blood
and the body tissues to occur rapidly.
Smallest blood vessels, connect arterioles to venules.

Are called the functional units of the cardiovascular
system.
A group of capillaries (10–100) functions together and
forms a capillary bed.

92. STRUCTURE OF BLOOD
VESSELS
Endothelium
Smooth muscle
Connective tissue
Collagen fibers
Elastic fibres
Tunica intima
Tunica media
Tunica adventitia

93. ARTERIES
Elastic artery
Muscular aryery
Arterioles
Capillaries

94. ELASTIC ARTERY

95. MUSCULAR ARTERY

96. ARTERIOLE

97. CAPILLARIES

99. STRUCTURE OF VEINS

100. VEINS
Venules
Medium sized veins
Large sized veins

101. SMALL VEIN

102. MEDIUM SIZED VEIN

103. LARGE VEIN

104. THANK YOU