imp points on epithelial tissue for cee exam nepal |neb|hseb notes

Dermis - the thick layer of living tissue below the epidermis which forms the true skin, containing blood capillaries, nerve endings, sweat glands, hair follicles, and other structures.

- it is mainly responsible for growth of hair follicle as it is supplied by nutrients and nutrient artery.

-Glands and ducts are internally lined with cuboidal epithelium.

-They are present in:

small ducts and tubules of kidneys
thyroid glands
salivary glands
pancreas
sweat gland of mammalian skin
Iris

-Cells of germinal epithelium are made up of simple cuboidal epithelium.

-It is the layer of cells around ovary or testes.

-In male it is the epithelium layer of seminiferous tubule.

-Glands and ducts are internally lined by cuboidal epithelium. 

-Cardiac muscles are found exclusively in the heart.

-have long, cylindrical and branched uninucleate cells

-Specialized intercellular junctions is called intercalated discs.

-They are 

striated
involuntary
do not get fatigued
contract quickly

-Connective tissue proper can be areolar, adipose, dense, elastic or reticular connective tissue.

-Areolar tissue consists of:

Fibroblasts-forms extracellular fibres
Macrophages-phagocytic
Mast cells-secretes serotonin, histamine and heparin
Plasma cells-secrete specific antibodies
Fat cells
Chromatophores-protects body from UV

-The basement membrane is a thin, fibrous, extracellular matrix of tissue that separates the lining of an internal or external body surface from underlying connective tissue in metazoans.

-It consists of:

 Basal lamina
Mucopolysaccharide
Fine fibrous network

 -Epithelium differs from connective tissues & supporting tissues by the presence of more cellular substance.

-It originates from all three germ layers: ectoderm, mesoderm and endoderm.

-Cells are compactly arranged.

-Intercellular matrix is absent.

-Cells of lowermost layer rest on basement membrane

-Endothelium of inner surface of blood vessels in vertebrates is formed by simple squamous cells.

-Simple squamous epithelium forms :

lining of alveoli
blood vessels
coelomic cavities
kidney(Glomerulus and Bowman's capsule)
Lymphatics

On the basis of mode of secretion, glands can be classified into:

Apocrine gland – Secretory products are collected near the tip of cell and released into duct by pinching off distended end. E.g= Mammary glands
Holocrine gland – whole cell disintegrate. E.g = Sebaceous glands of skin
Merocrine gland – Secretion by diffusion. E.g= Salivary glands, Pancreas, Sweat glands

-Mammary glands are modified sweat glands.

-Ceruminous glands are modified sweat glands.

-Meibomian glands are modified sebaceous glands.

-Mammary glands are modified sweat glands.

-Ceruminous glands are modified sweat glands.

-Meibomian glands are modified sebaceous glands.

-Gland of Zeis is modified sebaceous gland.

-Sweat glands occur all over the body

-They are most numerous on the forehead, the armpits, the palms and the soles of the feet.

- Sweat is mainly water, but it also contains some salts.

-Its main function is to control body temperature. As the water in the sweat evaporates, the surface of the skin cools.

-Horns,nails and hooves are of  keratin.

-Keratin is dead and waterproof fibrous protein that protects the skin covering body surface.

-Keratinised stratified squamous epithelium

-found on dry surfaces that are subjected to wear and tear; also found in our skin epidermis and hair.

-The ability for the liver to regenerate is central to liver homeostasis.

-Because the liver is the main site of drug detoxification, it is exposed to many chemicals in the body which may potentially induce cell death and injury. -

-The liver can regenerate damaged tissue rapidly thereby preventing its own failure.

-So liver has good power of regeneration.

Layers of the stomachwall, include

Serosa,
Muscularis-Outer longitudinal, middle circular and inner oblique muscle
Submucosa,
Mucosa- bears rugae and lined by
simple columnar epithelium

-Glandular epithelium is specialized for secretory activity.

-All glands arise from folding of epithelium.

-Glands may originate from all three germ layers: ectoderm, mesoderm and endoderm

-On the basis of duct, it can be classified into:

Endocrine gland
Exocrine gland

-Ciliated epithelium is found in:

Ciliated columnar in

1. Upper respi tract
2. Fallopian tubes
3. Uterus
4. Central part of spinal cord

• Pseudostratified ciliated columnar in respiratory epithelium.

  On the basis of mode of secretion, glands can be classified into:

  Apocrine gland – Secretory products are collected near the tip of cell and released into duct by pinching off distended end. E.g=Mammary glands

  Holocrine gland – whole cell disintegrate. E.g =
  Sebaceous glands of skin
  Merocrine gland – Secretion by diffusion. E.g=
  Salivary glands,
  Pancreas
  ,
  
  
  -Glandular epithelium is specialized for secretory activity.
  -All glands arise from folding of epithelium.
  -Glands may originate from all three germ layers: ectoderm, mesoderm and endoderm
  -On the basis of duct, it can be classified into:
  Endocrine gland
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  

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