Cell & tissue nursing
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Transcript of Cell & tissue nursing
Cell & Tissue
Rishi PokhrelMBBS, MD
MajAssistant prof of Anatomy
Classification• Somatic and germ cells
– Somatic cells are present in body structure and contain 46 pairs of chromosomes.
– Germ cells are formed for the purpose of reproduction and they are present only in testes or ovaries. They contain 26 pairs of chromosomes.
• On the basis of regeneration cells can be – Labile cells: cells undergoing continuous replication e.g. epithelium of skin
and mucosa, uterus, secretory glands, bone marrow, blood, spleen and lymphoid tissue.
– Stable cells: these cells undergo very slow or infrequent replication e.g. cells of liver, kidney and pancreas, fibroblasts, smooth muscle cells etc.
– Permanent cells: these cells do not divide after normal growth and development e.g. neurons, skeletal and cardiac muscle cells.
Composition
• water (70-80 %)• Proteins (10-20%)• Lipids (2%) and • Carbohydrates (1%).• Electrolytes like Sodium, Calcium, Chloride,
Potassium, magnesium, phosphate, sulfate and bicarbonate
Cell organells
• Cell membrane
Organelles
• Cytoplasm• Endoplasmic reticulum• Ribosomes• Mitochondria• Golgi bodies• Lysosomes• Nucleus• Centrioles
Nucleus
• Cytoskeleton• Cell junctions
– Tight junctions– Gap Junctions– Desmosomes
Tissue
• Epithelial tissue• Connective tissue• Muscular tissue• Nervous tissue
Epithelium
Glands
• “An organ in the body that secretes particular chemical substances for use in the body or for discharge into the surroundings”
• Epithelial cells are major components of glands
Classification• Duct system
– Endocrine
– Paracrine
– Exocrine• Simple
• Compound
– Mixed
• Means of secretion– Merocrine (Eccrine) – sweat, mammary– Apocrine – genitoanal glands– Holocrine – Sebaceous– Cells producing - Testis
Classification
• No of cells– Unicellular – goblet cells– Multicellular
• Type of secretion– Mucus– Serous
Classification
• Secretory component
– Tubular
– Acinar
– Coiled
– Branched
Classification
• Embryological origin– Ectodermal - sweat– Mesodermal – kidneys, testis– Endodermal - GI
Classification
Connective tissue
“Connective tissues (CT) are a group of
tissues which connects or binds other
tissues in the body”
CHARACTERISTICS
• Predominantly intercellular material (matrix)• Cells widely spaced• Development – mesoderm, neural crest
(head region)• Blood vessels – few supply• Classification – based on matrix, cells, fibres
Components
Cells Matrix
Ground substance Fibers
COMPOSITION: CONNECTIVE TISSUE
Composition
Components
Cells
Fixed
Fibroblasts
Adipocytes
Persistent mesenchymal
cells
Wandering
Macrophage
Mast cells
Plasma cells
Pigment cells
Eosinophil
Neutrophil
Matrix
Ground substance
Proteoglycans GAG /MPS
SO4
Non SO4
Fibers
Collagen
Elastic
Reticular
CONNECTIVE TISSUE
CELLS OF CONNECTIVE TISSUE
FIBRES
• COLLAGEN
• ELASTIC
• RETICULAR
Collagen
Ligament -TS
Ligament - LS
Elastic fibers
Reticular fibers
Collagen Elastic ReticularColor Pearly white Yellow -No Largest Next > In emb CTStain & appearance
Dull pink with eosin Bright, highly refractive
Not stained by H & E
Protein Collagen Elastin Reticulinthickness 1-12 um 0.1-0.2 um thinnestFeatures Wavy, do not branch, run
in bundles< wavy, branch, run singly
Straight, branch & anastomose-reticulum
Sites To provide strength; tendon, ligament etc.
To provide elasticity; lig nuche, vocal cords, lungs, aorta
To provide support; spleen, liver, lymph nodes, kidney, BM
GROUND SUBS
• Amorphous, transparent, semi-fluid gel
• Proteoglycans, hyaluronic acid (GAG), water
• Proteoglycans: chondroitin SO4, chondroitin
6 SO4, dermatan SO4, heparan SO4, heparin
SO4, keratan SO4
CLASSFICATION OF C. T.• Types of cells• Types of fibres• Amount of ground subs• Location
Connective tissue
Adult
Ordinary
Loose
Areolar
Adipose
Reticular
Dense
Regular
Tendon
Ligament
Aponeurosis
Irregular
Subcutaneous tissue
Specialized
Blood
Cartilage
Bone
Fetal
AREOLAR TISSUE
ADIPOSE TISSUE
TENDON L. S.
TENDON T. S.
BoneDefinition:
“Specialized connective tissue with a solid matrix which is mineralized & adapted for giving strength,
support & helping in wt. transmission”
Classification
General microstructure
• Non – lamellar bone / woven bone - immature
• Lamellar bone – mature
– Compact bone
– Spongy spongy
Bone
Cells
Osteoprogenator cells
Osteoblasts
Osteocytes
Bone lining cells
Osteoclasts
Matrix
Ground substance
Water
ProteoglycansChtn SO4, Hyal. Acid, osteocalcin, osteonection
Minerals Ca,Ca(OH)2(PO4)6
Fibers
Collagen
COMPOSITION
Osteoprogenitor /osteogenic cells
• From pluripotent stromal stem cells• Mesenchymal• Resemble young fibroblasts• In adults
• Deepest layer of periosteum• Endosteum
Osteoblasts• Resemble plasma cells• 15 – 30 µ • Roughly cuboidal• Nu eccentric• Cytoplasm deeply basophilic• EM – typical protein secreting cell• Function
– Synth & secretion of osteoid– Mineralization of matrix
Osteocytes
• Smaller & < basophillic• Major cell type• Oval, 25µ in long axis• Prominent nu• Cell in lacuna• Canaliculi 0.25 – 0.5µ
Osteoclasts
• Large cells
• 20 - 100µ
• Oval cells with multiple nu 15 – 20 or >
• Where active resorption
• Cells in pits – resorption bays/ lacunae of howship
Woven Bone / Non Lamellar Bone
• Most primitive form• Most bone – pre natal life• Post natal
• Repair of #• Rapidly growing bone tumors (osteogenic cells)
• Mechanically weak
Lamellar Bone/ Mature Bone
Haversian System
Bone Ground Section L.S.
Bone Ground Section T.S.
Periosteum• Outer covering• Absent
• Articular surface• Sesamoid bones
• Two layers• Outer fibrous • Inner cellular
• Sharpey’s fibres/ extrinsic fibres
Sharpey’s Fibres
Cartilage
• Specialized connective tissue for high resistance – tension, compression & shearing (Resilience & Elasticity)
• Avascular, no lymphatics, no nerve supply• Low metabolic rate
Constituents• Cells – chondrocytes, chondroblasts
– Located in lacunae
• Matrix
– Fibers: Collagen, elastic
– Ground substance: hyaluronic acid, proteoglycans, glycoproteins, chondroitin SO4
• Macromolecules, water & fibers bind together to give firm, flexible property
Perichondrium
• Dense CT that covers cartilage (except articular & fibrocartilage)
• Supplied by vessels & nerves
• Contains collagen fibers, fibroblasts
Types of Cartilage
• Hyaline– Costal– Articular
• Elastic• Fibro cartilage
Hyaline Cartilage
• Nose, trachea, larynx
• Bluish white color• Strong, rubbery &
flexible
Hyaline Cartilage
Elastic Cartilage
• Similar to hyaline • Fibers: collagen + elastic• Found in - auricle of ear, external auditory
canals, eustachian tubes, epiglottis• Maintains shape, deforms but returns to
shape; flexibility of organ; strengthens and supports structures.
Elastic Cartilage
Fibrocartilage• No Perichondrium
• Collagen fibres (Type I) – Densely packed bundles
– Feathery appearance
– Merge with surrounding CT
• Scanty Chondrocytes– Small cells in lacunae
– form short rows between dense bundles of collagen fibres
Identifying features
• Costal cartilage– Perichondrium +– Ground glass appearance– Cells ++
• Articular cartilage– Perichondrium –– Ground glass appearance– Cells +
• Elastic cartilage– Perichondrium +– Elastic fibers seen– Cells ++
• Fibrocartilage– Perichondrium –– Feathery appearance– Cells +
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