Histology Flashcards

1
Q

What covers the nasopharynx and nasal cavity

A

Respiratory epithelium

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2
Q

What covers oro and layngopharynx

A

Stratified squamous epitelium (non-keratenized)

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3
Q

Anterior tongue is covered by

A

Stratified squamous epithelium, thick and papillae on dorsal surface, thin on ventral

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4
Q

Histology of posterior tongue

A

Smooth stratified squamous epithelium which only has circumvallate papillae and large lymphoid aggregate in submucosa

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5
Q

Papillae of tongue

A

Most of the dorsal surface if covered by filiform papillae. Fungiform are found interspaced. In front of the sulcus terminalis lies a v-shaped circumvallate papillae. Laterally lie the foliate papillae.

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6
Q

Function of serous gland in papillae

A

The papillae are arranged in a moat like structure. The serous glands secrete a watery fluid that helps wash this moat and make ready for subsequent tasting.

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7
Q

Characteristic of posterior 1/3rd of tongue

A

Lots of lymphoid tissue with some lymphoid follicles

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8
Q

Layers of digestive tract, inside to out

A

Mucosa, submucosa, muscularis externa and serosa or adventitia

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9
Q

Differentiate serosa and adventitia

A

Serosa is simple squamous epithelium, shiny and sparse layer of loose connective tissue. It covers external layers of organs. Adventitia is loose connective tissue that serves to hold organs in place. It oftens grades off into adjacent adventitia

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10
Q

Parts of mucosa

A

Epithelium, lamina propriae and muscularis mucosae

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11
Q

Parts of muscularis externa

A

Inner circular and outer longitudinal smooth muscles

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12
Q

What is Barrett’s oesophagus

A

Metaplastic change in oesophagus from stratified squamous epithelium to simple columnar with goblet cells. This can lead to oesophageal adenocarcinoma

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13
Q

What is the gastro-oesophageal junction

A

Point where stratified squamous epithelium of oesophagus transitions to columnar epithelium of cardia of stomach

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14
Q

What can the layer of stomach cells be divided into

A

Pit, isthmus, neck, base

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15
Q

Distribution of cells in gastric gland

A

Pit - Surface mucous cells
Isthmus - Parietal cells
Neck - Stem cells and neck mucous cells
Base - Chief cells with few parietal and neuroendocrine/enteroendocrine cells

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16
Q

Parietal vs chief cells

A

Parietal - Called oxyntic cells, make HCl, mostly at isthmus, lots of mitochondria, histamine/gastrin and acetylcholine receptors
Chief cells - Have zymogen granules with pepsinogen, mainly at base

17
Q

Why do chief cells stain intensely

A

Due to presence of pepsinogen

18
Q

Mucosa in different regions of stomach

A

Cardia - Deep gastric pits that branch into loosely packed glands
Body - Shallow pits with long straight gastric glands
Pylorus - Deep gastric pits that branch, coiled at higher density than cardia

19
Q

Function of extra layer oblique internally to circular and longitudinal layer of muscularis externa

A

Churning action of stomach

20
Q

Modification at gastroduodenal junction

A

Inner circular layer of muscularis externa is thickened to form pyloric sphincter

21
Q

Pits in small intestine are called

A

Pits of Lieberkuhn

22
Q

Compare regions of small intestine

A

Duodenum - Has Brunner’s glands in submucosa
Jejunum - Tallest villi on circular folds of mucosa and submucosa, the plicae circularis
Ileum - Lymphoid aggregations called Payers patch in submucosa and lamina propria

23
Q

What are enterocytes

A

Tall columnar cells with a brush border appearance, main absorptive cells

24
Q

Function of goblet cells in small intestine

A

Secrete mucin to protect epithelium and lubricate passage of material

25
Q

Function of paneth cells in small intestine

A

At base of crypts of Lieberkuhn, secrete lysozyme and defensins (bacteriocidals) and regulate bacterial flora

26
Q

Function of enteroendocrine cells (neuroendocrine)

A

Secrete hormones such as gastrin, CCK, vasoactive intestinal peptide (VIP) to control secretion and motility

27
Q

Function of Brunners gland in duodenum

A

Chyme stimulates this to produce a thin, alkaline mucous to neutralise the chyme. Present in submucous

28
Q

What are plicae circularis

A

Circular folds, large valvular folds protruding into the lumen. Contain villi

29
Q

Where are the folds in the jejunum

A

In the mucosa and submucosa

30
Q

Where in the small intestine are large areas of GALT - gut associated lymphoid tissue

A

Ileum, contains scattered lymphoid tissue called Peyer’s patches.

31
Q

Principle cells of large intestine

A

Absorptive - For removal of salt and water

Goblet - Secretion of mucus to lubricate the colon

32
Q

Where do the large intestinal tubular glands extend to

A

Muscularis mucosae

33
Q

Outer smooth longitudinal layer in large intestine is arranged into three muscular strips called?

A

Teniae coli

34
Q

Difference in structure between colon and appendix

A

Appendix has less abundant crypts and circular arrangement of lymphoid tissue in submucosa and lamina propriae. This lymphoid tissue declines with age

35
Q

What is the rectoanal junction

A

Distinct junction between mucosa of rectum and stratified squamous epithelium of anal canal

36
Q

What plexus controls GI tract motility

A

Myenteric plexus between layers of muscularis externa

37
Q

What helps control secretions in GI epithelium

A

Submucosal plexus that also controls muscles of muscularis mucosa