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GENERAL HISTOLOGY
DR SAMINA SHAHEEN
ASSISTANT PROFESSOR OF ANATOMY
KEMU
BASIC TISSUES
 Epithelium
 Connective tissue
 Muscular tissue
 Nervous tissue
 Organs divided into:
 Parenchyma –cells
 Stroma –supporting tissue
SIMPLE SQUAMOUS EPITHELIUM
 Composed of very thin flat
irregular shaped cell that form
a continuous surface
 Also called...
SIMPLE CUBOIDAL EPITHELIUM
 Cells appear cube or box like
 Nucleus is rounded & placed in
centre of cell
 cells rest on...
SIMPLE COLUMNAR NON
CILIATED EPITHELUIUM
 Composed of tall columnar
cells
 Rests on basement
membrane
 Nucleus in elong...
SIMPLE COLUMNAR CILIATED
EPITHELIUM
 CILIA present on surface of
simple columnar epithelium
 Present in:
 Small intrapu...
PSEUDOSTRATIEIED EPITHELIUM
 NON-CILIATED
 Variant of simple columnar
epithelium
 Tall & short cells are present
 All ...
PSEUDOSTRATIEIED EPITHELIUM
 CILIATED
 This epithelium
may be ciliate with
goblet cells
 Example:
 Trachea
 Larger br...
STRATIFIED EPITHELIA
STRATIFIED SQUAMOUS NON
KERATINIZEXEPITHELIUM
 Multi-layered
 Basal layer low columnar or high
cubo...
STRATIFIED SQUAMOUS
KERATINIZED EPITHELIUM
 Features same as
non-keratinized
epithelium except
 Surface layer
composed o...
TRANSITIONAL EPITHELIUM
 IN RELAXED STATE
 Is 4-5 cell layer thick
 Basal layer is cuboidal
 Intermediate layer is
pol...
STRATIFIED CUBOIDAL
 Consists of two
layers of cuboidal
cells
 Cells of superficial
layer are smaller
 Examples :
 Duc...
 STRATIFIED COLUMNAR EPITHELIUM
 Basal layer consists of low columnar or cuboidal cells
 Surface layer is of tall colum...
CONNECTIVE TISSUE
 Characterized by the presence of relatively few cells & abundant
intercellular substance
 FUNCTIONS
...
CELLS OF CONNECTIVE
TISSUE
 Fibroblasts
 Mast cells
 Plasma cells
 Macrophages (histiocytes)
 Leukocytes
 Adipocytes
MESENCHYMAL CELLS
FIBROBLASTS
MACROPHAGES
PLASMA CELLS
MAST CELLS
ADIPOCYTES
FIBERS OF CONNECTIVE
TISSUE
 Collagen
 Elastic
 Reticular
COLLAGEN FIBERS
ELASTIC FIBERS
RETICULAR FIBRES
GROUND SUBSTANCE
 Glycosaminoglycans (mucopolysaccharides)
 Proteoglycans
 Multiadhesive glycoproteins
TYPES OF CONNECTIVE
TISSUE
 Embryonic connective tissue
 Mesenchyme
 Mucous
 Adult connective tissue
 Connective tiss...
LOOSE CONNECTIVE TISSUE &
DENSE IRREGULAR CONNECTIVE
TISSUE
DENSE REGULAR CONNECTIVE
TISSUE
RETICULAR TISSUE
EMBRYONIC CONNECTIVE TISSUE
MESENCHYME MUCOUS
CARTILAGE
 Cells (chondrocytes)
 Extra-cellular matrix
 Fibrils
 Ground substance

Proterglycan

Glycosaminoglycanp ...
TYPES OF CARTILAGE
 Hyaline
 Elastic
 Fiibrocartilage
HYALINE CARTILAGE
ELASTIC CARTILAGE
FIBROCARTILAGE
BONE
 Cells
 Osteocytes
 Osteoblasts
 Osteoclasts
 Bone matrix
 Organic

Collagen type 1

Ground substance
 Prote...
TYPES OF BONE
(GROSS OBSERVATION)
TYPES OF BONE
(MICROSCOPIC EXAMINATION)
PRIMARY/IMMATURE BONE SECONDARY/ MATURE
MUSCLE
 Skeletal muscle
 Smooth muscle
 Cardiac muscle
ORGANIAZATION OF SKELETAL
MUSCLE
 Endomysium – muscle fiber
 Perimysium – fascile
 Epimysium – entire muscle
ORGANIZATION OF SKELETAL
MUSCLE
SKELETAL MUSCLE
CARDIAC MUSCLE
CARDIAC MUSCLE
SMOOTH MUSCLE
SMOOTH MUSCLE
COMPARISON BETWEEN THE THREE
TYPES OF MUSCLES
NERVE TISSUE & NERVOUS
SYSTEM
 Central nervous system
 Brain & spinal cord
 Peripheral nervous system
 Spinal, cranial...
STRUCTURE OF NEURON
 Cell body
 Axon
 dendrite
GLIAL CELLS
 CNS
 Oligodendrocytes
 Ependymal cells
 Astrocytes
 Microglial cells
 PNS
 Neurolemmocytes
(Schwann ce...
PERIPHERAL NERVOUS
SYSTEM
COMPONENTS OF PNS
• Nerves
• Ganglia
• Nerve endings.
CONNECTIVE TISSUE COMPONENTS OF A
PERIPHER...
• Perineurium is a specialized
c.tissue surrounding a nerve
fascicle. It serves as a
metabolically active diffusion
barrie...
GANGLIA
• It is an ovoid structures
contain neuronal cell bodies
and glial cells supported by
c.tissue.
• Serves as relay ...
continued….
• Connective tissue capsule which is continuous with the
epineurium of nerve on which ganglion is situated Gan...
AUTONOMIC GANGLIA• They are associated with
sympathetic and parasympathetic
division of autonomic nervous
system.
• Arrang...
STRUCTURE OF THE
CEREBRAL CORTEX
 The cerebral cortex
forms a complete
covering of the cerebral
hemisphere. It is
compose...
PYRAMIDAL CELLS
 Contains a large vesicular
nucleus
 Abundant nissl granules
 One main dendrite arises
from the apex an...
 Nonpyramidal cells
 Stellate/granule cells: small polygonal
perikaryon; each cell gives off a number of small
dendrites...
CONTINUED
 Martinotti cells: small, multipolar cells found in
the deeper layers of the cerebral cortex; has a
short dendr...
LAYERS OF THE CEREBRAL
CORTEX
 Molecular or Plexiform Layer:
composed chiefly of cell processes (of the
cells lying in th...
 Internal Granular Layer: consists of
closely packed stellate cells. There is a
high concentration of horizontally
arrang...
 Multiform Layer:
composed of neurons
of many shapes. Also
contains pyramidal
cells, stellate cells
and martinotti
cells....
 All areas of cerebral cortex do not possess six layers.
 They are called as heterotypical as compared to
majority which...
CEREBELLUM
 Cerebellum is
composed of an outer
covering of gray
matter called cortex
and inner white
matter. Embedded in
...
STRUCTURE OF
CEREBELLIUM
 The cerebellar cortex on section shows
three layers from within outwards.
 Molecular layer: Th...
 The Stellate cells have small star- shaped perikarya.Each cell
has many short thin dendrites and a fini unmyelinated axo...
PURKINJE CELL LAYER
 The Purkinje cells are large Golgi type l
neurons they are flask shaped and are
arranged in a single...
GRANULAR LAYER
Small granule cells with dark staining nucleous with very
little cytoplasm.
Also present in this layer are ...
AFFERENT FIBERS OF
CEREBELLUM
 Climbing fibers .They originate from
inferior olivery nucleus of
m.oblongata.Asthey enter ...
CEREBELLUM
CEREBELLUM
SENSORY NERVE ENDINGS
OR RECEPTORS
• Morphologically divided into:
• Non –encapsulated or free nerve endings
• Encapsulate...
ENCAPSULATED NERVE
ENDINGS
Tactile corpuscles of meissner:
• Located in non hairy skin especially finger tips,
palm and so...
RUFFINIS ENDINGS
 Fusiform struture 1-2mmin length and
present in skin in joint capsule.
 Consist of thin c.tissue capsu...
END BULB OF KRAUSE
 They are spherical bodies covered by a
c.tissue capsule and contain a central
cavity.
 A myelinated ...
MUSCLE SPINDLES
• Present in skeletal
muscle.
• Fusiform structure,0.5-
5mm in length.
• Consist of intrafusal fibers
and ...
TENDON ORGANS OF
GOLGI
 Located in tendons close to muscle
tendon junction.
 Consist of small bundle of collagen
fibers ...
NERVE FIBERS
PERIPHERAL NERVE
 Endoneurium
 Perineurium
 epineurium
CIRCULATORY SYSTEM
 Heart
 Arteries
 capillaries
 Veins
23-86
Blood Vessel Tunics
 Tunica Intima, or Tunica Interna
 innermost layer
 composed of:

an endothelium (simple squ...
23-87
Blood Vessel Tunics
Tunica Externa, or Tunica Adventitia
 outermost layer
 composed of:

areolar connective tissu...
88
23-89
Arteries
 In the systemic circulation, carry oxygenated
blood to the body tissues.
 Pulmonary arteries carry deoxy...
90
23-91
Capillaries
 Contain only the tunica intima, but this layer consists
of a basement membrane and endothelium only.
...
STRUCTURE OF BLOOD
VESSELS
 Endothelium
 Smooth muscle
 Connective tissue
 Collagen fibers
 Elastic fibres
 Tunica i...
ARTERIES
 Elastic artery
 Muscular aryery
 Arterioles
 Capillaries
ELASTIC ARTERY
MUSCULAR ARTERY
ARTERIOLE
CAPILLARIES
STRUCTURE OF VEINS
VEINS
 Venules
 Medium sized veins
 Large sized veins
SMALL VEIN
MEDIUM SIZED VEIN
LARGE VEIN
THANK YOU
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General histology

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General histology

  1. 1. GENERAL HISTOLOGY DR SAMINA SHAHEEN ASSISTANT PROFESSOR OF ANATOMY KEMU
  2. 2. BASIC TISSUES  Epithelium  Connective tissue  Muscular tissue  Nervous tissue
  3. 3.  Organs divided into:  Parenchyma –cells  Stroma –supporting tissue
  4. 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
  5. 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
  6. 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. 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 
  8. 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. 9. PSEUDOSTRATIEIED EPITHELIUM  CILIATED  This epithelium may be ciliate with goblet cells  Example:  Trachea  Larger bronchi
  10. 10. 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 
  11. 11. STRATIFIED SQUAMOUS KERATINIZED EPITHELIUM  Features same as non-keratinized epithelium except  Surface layer composed of non- nucleated cells  They acquire protein keratin  Example :  Skin
  12. 12. 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
  13. 13. STRATIFIED CUBOIDAL  Consists of two layers of cuboidal cells  Cells of superficial layer are smaller  Examples :  Ducts of salivary glands  Ducts of sweat
  14. 14.  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
  15. 15. CONNECTIVE TISSUE  Characterized by the presence of relatively few cells & abundant intercellular substance  FUNCTIONS  STRUCTURE  Cells  Fibres  Ground substance Develops from MESENCHYME
  16. 16. CELLS OF CONNECTIVE TISSUE  Fibroblasts  Mast cells  Plasma cells  Macrophages (histiocytes)  Leukocytes  Adipocytes
  17. 17. MESENCHYMAL CELLS
  18. 18. FIBROBLASTS
  19. 19. MACROPHAGES
  20. 20. PLASMA CELLS
  21. 21. MAST CELLS
  22. 22. ADIPOCYTES
  23. 23. FIBERS OF CONNECTIVE TISSUE  Collagen  Elastic  Reticular
  24. 24. COLLAGEN FIBERS
  25. 25. ELASTIC FIBERS
  26. 26. RETICULAR FIBRES
  27. 27. GROUND SUBSTANCE  Glycosaminoglycans (mucopolysaccharides)  Proteoglycans  Multiadhesive glycoproteins
  28. 28. TYPES OF CONNECTIVE TISSUE  Embryonic connective tissue  Mesenchyme  Mucous  Adult connective tissue  Connective tissue proper  Loose  Dense  Irregular  Regular  Specialized  Reticular  Adipose  Bone  Cartilage
  29. 29. LOOSE CONNECTIVE TISSUE & DENSE IRREGULAR CONNECTIVE TISSUE
  30. 30. DENSE REGULAR CONNECTIVE TISSUE
  31. 31. RETICULAR TISSUE
  32. 32. EMBRYONIC CONNECTIVE TISSUE MESENCHYME MUCOUS
  33. 33. CARTILAGE  Cells (chondrocytes)  Extra-cellular matrix  Fibrils  Ground substance  Proterglycan  Glycosaminoglycanp (mucopolysaccharide)
  34. 34. TYPES OF CARTILAGE  Hyaline  Elastic  Fiibrocartilage
  35. 35. HYALINE CARTILAGE
  36. 36. ELASTIC CARTILAGE
  37. 37. FIBROCARTILAGE
  38. 38. BONE  Cells  Osteocytes  Osteoblasts  Osteoclasts  Bone matrix  Organic  Collagen type 1  Ground substance  Proteoglycans  Glycoproteins  Inorganic  Hydroxyapatite  Ca Po4, magnesium, bicarbonate, citrate, sodium & potassium
  39. 39. TYPES OF BONE (GROSS OBSERVATION)
  40. 40. TYPES OF BONE (MICROSCOPIC EXAMINATION) PRIMARY/IMMATURE BONE SECONDARY/ MATURE
  41. 41. MUSCLE  Skeletal muscle  Smooth muscle  Cardiac muscle
  42. 42. ORGANIAZATION OF SKELETAL MUSCLE  Endomysium – muscle fiber  Perimysium – fascile  Epimysium – entire muscle
  43. 43. ORGANIZATION OF SKELETAL MUSCLE
  44. 44. SKELETAL MUSCLE
  45. 45. CARDIAC MUSCLE
  46. 46. CARDIAC MUSCLE
  47. 47. SMOOTH MUSCLE
  48. 48. SMOOTH MUSCLE
  49. 49. COMPARISON BETWEEN THE THREE TYPES OF MUSCLES
  50. 50. 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)
  51. 51. STRUCTURE OF NEURON  Cell body  Axon  dendrite
  52. 52. GLIAL CELLS  CNS  Oligodendrocytes  Ependymal cells  Astrocytes  Microglial cells  PNS  Neurolemmocytes (Schwann cells)
  53. 53. 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.
  54. 54. • 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.
  55. 55. 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
  56. 56. 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.
  57. 57. 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.
  58. 58. 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
  59. 59. 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,
  60. 60.  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.
  61. 61. 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.
  62. 62. 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.
  63. 63.  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.
  64. 64.  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.
  65. 65.  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.
  66. 66. 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.
  67. 67. 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.
  68. 68.  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.
  69. 69. 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
  70. 70. 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. .
  71. 71. 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
  72. 72. CEREBELLUM
  73. 73. CEREBELLUM
  74. 74. 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.
  75. 75. 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.
  76. 76. 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.
  77. 77. 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.
  78. 78. 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.
  79. 79. 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.
  80. 80. NERVE FIBERS
  81. 81. PERIPHERAL NERVE  Endoneurium  Perineurium  epineurium
  82. 82. CIRCULATORY SYSTEM  Heart  Arteries  capillaries  Veins
  83. 83. 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)
  84. 84. 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
  85. 85. 88
  86. 86. 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
  87. 87. 90
  88. 88. 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.
  89. 89. STRUCTURE OF BLOOD VESSELS  Endothelium  Smooth muscle  Connective tissue  Collagen fibers  Elastic fibres  Tunica intima  Tunica media  Tunica adventitia
  90. 90. ARTERIES  Elastic artery  Muscular aryery  Arterioles  Capillaries
  91. 91. ELASTIC ARTERY
  92. 92. MUSCULAR ARTERY
  93. 93. ARTERIOLE
  94. 94. CAPILLARIES
  95. 95. STRUCTURE OF VEINS
  96. 96. VEINS  Venules  Medium sized veins  Large sized veins
  97. 97. SMALL VEIN
  98. 98. MEDIUM SIZED VEIN
  99. 99. LARGE VEIN
  100. 100. THANK YOU

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