Special cells in Stomach,Small intestine

GASTRIC GLAND
It has 4 special types of cells

• Chief cells or zymogen cells

¤ secrete pepsinogen

¤ abundant in fundus of gastric gland

 •  Parietal or oxyntic cells

¤ secrete HCL and intrinsic factor of castle

¤ abundant in isthmus

 •  mucous cells

¤ secrete mucus

¤ abundant in neck

 • neuroendocrine cells

¤ G-cells : gastrin ;S-cells : somatostatin;enterochromaffin like cell : histamine

¤ present more deep in fundus

BRUNNER'S GLAND

 • characteristic of upper duodenum

 • secrete mucus

PANETH CELLS

 • Charecteristic of small intestine

 • granular,secretory,eosinophilic,exocrine cell

 • present deeply in crypts and unlike other cells dont migrate to surface of small intestine mucosa

 • life span is 28 days

 • contains zinc,lysosome,rough endoplasmic reticulum

 • secrete lysozyme,cryptidin,tnf a,phospholipase a2,antichymotrypsin

PAYERS PATCHES

 • characteristic of ileum

 • aggregates of lymphoid nodules

SPECIAL CELLS OF SMALL INTESTINE

 • mucosa of small intestine invaginates to form crypts of luberkuhn and evaginates yo form villi

• in villi :

1) goblet cells - secrete mucus and provides lubrication and barrier to infection

2) M cells (microfolds) - covers underlying lymphocytes,process antigens and present it to underlying lymphocytes

3) lymphocytes

• in crypts :

1) stem cells - replaces old dying cells in mucosa

2) paneth cells

3) neuroendocrine cells/APUD cells

NERVE INERVATION OF GIT

1) Auerbachs plexus/myentric

• between outer longitudinal muscle and inner circular muscle

• has motor control over git

2) Meissners plexus

• between circular muscle layer and mucosa

• has secretion control

Read more

Oesophagus

4 LAYERS OF OESOPHAGEAL WALL

• Mucosa : lined by non keratinised stratified squamous epithelium
• Submucosa :
• Muscularis externa : Toughest layer;Upper 1/3 has skeletal muscle;lower 1/3 has smooth muscle;middle 1/3 has both skeletal and smooth muscles
• Serosa

4 CONSTRICTIONS OF OESOPHAGUS

• @ 15cm (from incisors)>> @ pharyngoesophageal jn>>c6 level
• @23cm>> @ crossing of arch of aorta
• @27 cm>> @ left bronchus crossing
• @40cm>> @ piercing of diaphragm

5 BLOOD SUPPLY

• Bronchial artery
• Inferior thyroid artery
• Descending thorasic aorta
• Left gastric artery
• Left inferior phrenic artery

6 LENGTH OF OESOPHAGUS

• 15cm

Read more

Types of Epithelium

A) Squamous Epithelium

     1) Simple Squamous : (mnemonic - all MEn are Ant)

• All - alveoli of lungs
• M - mesothelium of pleura,pericardia,peritoneum
• En - endocardium,endothelium
• An - ansa nephroni (renal loop of henle)

    2)  Keratinised stratified squamous

• Skin(epidermis)
• ducts of sebaceous gland(all ducts of glands are lined by cuboidal epit except sebaceous gland duct)

   3) Non keratisnised stratified squamous

• Mouth,tongue,tonsil,pharynx,esophagus
• Cornea
• Vagina

B) Columnar epithelium

   1) Simple columnar 

• Stomach
• Large intestine
• Cervical canal

   2) columnar with striated border(regular microvilli)

• Small intestine

   3) columnar with brush border(irregular microvilli)

• Gall bladder

   4) columnar with cilia(mnemonic - U Race)

• U - Uterus and uterine tubes
• R - respiratory epithelium
• A - auditory tube and parts of middle ear
• C - cervical canal and ventricles
• E - efferent ductules

   5) Pseudostratified columnar (mnemonic : all/ol trachea and auditory ducts are ur MP)

• Ol - olfactory epith
• Trachea and large bronchi
• Auditory tubes
• Ducts - ductus deferens
• Ur MP- urethra membranous and penile

   6) secretory columnar(goblet cells)

• Stomach,small intestine,large intestinee
• Trachea ,bronchi

C) Cuboidal epithelium (Mnemonic  DEFG)

• D - ducts of glands
• E - eye
• F - follicles of thyroid
• G - germinal epithelium

D) Transitional epithelium

• Urothelium( calyx ,pelvis,ampulla,ureter,bladder,part of uretha)

Bartholin gland

• Homologous to bulbourethral gland of male
• Ducts open outside hymen on inner surface of labia minora
• Acini lined by cuboidal,mid portion by transitional and outer portion by squamous epithelium

Read more