Digestive system Histology

Done by : Raghda Al-Droubi

Digestive tract

• General structure of the digestive tract

• Oral cavity

• Esophagus

• Stomach

• Small & large intestines

• Associated glands and organs

GENERAL STRUCTURE OF THE DIGESTIVE TRACT

• Digestive tract wall made up of four main layers

1. Mucosa

2. Submucosa

3. Muscularis

4. Serosa or adventitia

• Histology of the wall (4 layers):

1- mucosa

-epithelial lining

-Lamina propria (CT , blood vessels , lymphatic , gland , layer of smooth muscle –muscularis mucosae-)

-Muscularis mucosae :

muscularis layer in theيتحرك بغض النظر عن ال mucus membraneمشان تخلي ال wall.

2- sub mucosa

contain Meissner's plexus.

3- muscularis outer : longitudinal , inner :circular .

Auerbach plexus > between inner and outer muscular layer .

4- adventitia or serosa

adventitia : CT (extra peritoneum) ,

serosa : CT+ serous membrane (intra peritoneum).

Mucosa

Submucosa

Muscularis

Serosa

Meissner plexus

Aurbach plexus

ORAL CAVITY • Tongue : 1- papilla : a- Filliform> most abundant, flame or conical shaped ,no taste buds. b- fungiform>dorsum part of the tongue , mushroom shaped , taste buds. c- foliate> posteriolaterally on 2 sides of the tongue, prominent in animal. d- circumvallate> anterior to sulcus terminalis , # (8-12) , largest one ,one papillae contain 250-300 taste buds 2- lining str. Sq. epithelium > Keratinized (dorsum) , non keratinized (ventral). 3- salivary gland 4- skeletal muscle

tongue

Fungiform Filliform

• Circumvallate :

Deep,

large,

str. Sq. epi. on the top,

CT in the middle ,

taste buds on 2 sides .

ORAL CAVITY

• Basal cell> basement membrane .

• S > supporting .

• N > taste sensation .

هون في خربطة

في االحرف الزم

Sمكان ال Nال

ESOPHAGUS

Esophagus • Tube >> 1- mucosa : Lining > non keratinized str. Sq. epi. Lamina propria Muscularis mucosae 2- sub mucosa : contain esophageal glands. 3- Muscular layer : Inner circular , Outer longitudinal. Upper third > skeletal muscle Middle third > mixed muscle Lower third > smooth muscle 4- Adventitia.

esophagusمن ال اخر سم اذا اخدت ألنه thickeningما في كتير -1

physiological sphincter .

Cardiac glandممكن اشوف -2

in lamina propria . serosaرح اشوف -3

SS

LP

MM

D

STOMACH

STOMACH

o Consists of:

Cardia

Fundus

Body

Pylorus

Note: Cardia & pylorus are primarily involved in mucus production, while fundus & body are involved in acidic gastric juice secretion

Note: Cardia & pylorus are similar in histological features, while fundus & body are similar to each other .

STOMACH

• Mucosa

• Submucosa

• Muscularis

• Serosa

Gastric pits

glandو هاي ال Glandبتدخلنا عال Gastric pitsال •

:من اهمهم cellsفيها كتير

• 1-chief cell > produce pepsinogen , basophilic because of ribosomes.

• 2- parietal cell> produce HCL ,IF , eosinophilic because of mitochondria.

Mucosa

• Section from pyloric sphincter (anatomical sphincter ):

Gastric pits lead to gastric gland

Muscularis mucosae

Sub mucosa

Thickening in muscular layer , specifically in circular muscularis

SMALL INTESTINE

o Duodenum > Brunner cells ,

o Jejunum > plicae circulares , paneth cells (immune cells),

o Ileum > payers patches .

:بميزهم وجود ال 1-Villi 2-brush border (microvilli) 3-lining > simple columnar 4- goblet cells

Paneth cell

• Orientation of inner circular and outer longitudinal muscle .

LARGE INTESTINE

• Consists of: – Cecum

– Ascending colon

– Transverse colon

– Descending colon

– Sigmoid colon

– Rectum

:بميزهم 1-NO Villi 2-brush border (microvilli) 3-lining > simple columnar 4- goblet cells

Intestinal crypts without projections.

Large intestine

• Goblet cells stained be pas stain .

ANUS

Rectum lining > columnar epi. Pectinate line non keratinized str. Sq. epi. White line keratinized str. Sq. epi.

• Section from anal canal :

- Columnar epithelium (Lt side)

- Intestinal crypts

*transferred to

-non keratinized str. Sq. epi. (Rt side)

اميز بين التحّول الي بصير مشان **

نهاية ال )و anal canalفي ال

esophagus بداية الstomach )

:: بالقي Anal sectionفي ال

Skeletal muscle , sweat and sebaceous gland .

Salivary glands

parotid • Serous acinar > nuclei more prominent .

> dark .

submandibular • Contains the 2 types of glands (serous and mucous).

• Serous demilune > serous part of gland surround the mucous acinar

• Striated duct > columnar epi. + cells contain striations toward the nucleus .

• Intercalated duct > cuboidal epi.

sublingual • Mixed gland ,, mucous acinar is more prominent . • Mucous acinar > basal nuclei > pale

pancreas 1-surrounded by CT capsule 2- septation into lobules 3-Endocrine> islets of Langerhans (pale in colour)

Exocrine > serous acinar

Liver

• Lobule , central vein , portal triad , sinusoid toward the centre. • Hepatocytes> eosinophil > # of nucleus ( one or two ) • kupffer cell > nucleus less prominent > less round

Gallbladder • 4 layers : 1- mucosa > lining simple columnar epi. >lamina propria 2- sub mucosa > very thin **** 3- muscularis layer 4- adventitia or serosa .

Thanks

و لم نختر مهنة الرداء األبيض عن عبث ، بل

.اخترناها ألن عشق لاير مدريد يجري في عروقنا<3