Week 7 lecture Hist

Question 1

MUCOSA components

Answer 1

epithelium
lamina propria
muscularis mucosae

Question 2

SUBMUCOSA components

Answer 2

connective tissue
+/- glands, lymph nodules
large vessels
nerve plexi

Question 3

MUSCULARIS EXTERNA components

Answer 3

smooth muscle
nerve plexi

Question 4

serosa components

Answer 4

mesothelium +
connective tissue

Question 5

mucosa epithelium functions

Answer 5

Most variable layer, adapted to function
* Protection = cell layers, tight junctions
* Absorption = +/- microvilli
* Secretion = +/- glands that open onto
the surface
* +/- goblet cells

Question 6

ADVENTITIA components

Answer 6

connective tissue

Question 7

mucosa lamina propria

Answer 7

Loose connective tissue, blood vessels,
immune cells

Question 8

mucosa - muscularis mucosa

Answer 8

circular layer of smooth muscle
* For localised movement

Question 9

submucosa consists/made of

Answer 9

Dense irregular connective tissue
* +/- Glands & lymph nodes
* Peripheral nerve plexi & vessels

Question 10

Muscularis Externa

Answer 10

• Variable
• Smooth Muscle arranged in different orientations
• Function = peristalsis
• Peripheral nerve plexi between muscle layers

Question 11

Serosa

Answer 11

Simple squamous epithelium = mesothelium
Small amount of loose connective tissue
Numerous adipocytes
Nerves, blood vessels, lymphatic vessel

Question 12

adventitia

Answer 12

NO epithelium
Loose and/or dense irregular connective tissue
Nerves, blood vessels and lymphatic vessels

Question 13

What’s unique about the OESOPHAGUS?

Answer 13

Mucosa
Stratified squamous epithelium
Thick muscularis mucosa

Submucosa
Many glands in upper oesophagus for lubrication

Muscularis externa
Striated muscle in upper part
Smooth muscle in lower part

Sphincters

Question 14

STOMACH
distinguishing histological features : mucosa

Answer 14

1. Simple columnar epithelium creating gastric pits
2. Gastric glands
3. Three layers of smooth muscle in muscularis externa
4. Rugae

muscularis mucosae very thin

Question 15

oesophagus distinguisihng features

Answer 15

Mucosa
Stratified squamous epith.
Thick muscularis mucosae

Submucosa
Glands, CT
lymph nodules

Muscularis externa
muscle
vessels, nerves

Adventitia
CT, adipose
vessels, nerves

Question 16

STOMACH
distinguishing histological features : lamina propria

Answer 16

Lamina propria
* loose CT with immune cells
* lymphocytes, plasma cells,
eosinophils & macrophages
STOMACH

Question 17

STOMACH
distinguishing histological features : submucosa

Answer 17

• dense irregular connective tissue
• Vessels
• Meissner’s nerve plexus
• adipose
  STOMACH

Question 18

STOMACH
distinguishing histological features : muscularis externa

Answer 18

• 3 layers of smooth muscle
• nerves & vessels between
• Myenteric (Auerbach’s Plexus)

Question 19

STOMACH components

Answer 19

Gastric pit
where the surface epithelium
dips down into lamina propria

Gastric gland
branched tubular
variety of cell types

Enteroendocrine cells
Hormones - Gastrin, VIP….

Question 20

stomach surface - epithelial cells

Answer 20

Entire surface of the gastric mucosa is lined with
columnar epithelial cells that dip down to form gastric pits
Mucous cells located between the epithelial cells
Most abundant in neck of glands
Secrete mucous
Nucleus at base of cell, apical cytoplasm filled with mucous

Question 21

parietal cells

Answer 21

Parietal cells secrete HCl (digestion) and intrinsic factor (allows body to absorb Vit B12
loss of production Pernicious Anaemia)

• Intracellular canalicular system that opens into lumen of gland
• numerous microvilli projections
• ++ mitochondria

Question 23

parietal cell TE micrograph

Answer 23

• triangular shaped cell
• central nucleus
• cytoplasm 40% mitochondria
  + sER abundant
• intracellular canaliculi
  with microvilli

Question 24

cheif cells

Answer 24

located deep in the gland
protein secreting ( pepsinogen)
rER & granules gives cytoplasm a bluish colour
Pepsinogen + HCl (pepsin) causes protein ==> peptides

Question 25

Enteroendocrine cells - G cells, enterochromaffin cells

Answer 25

Secrete into the blood vessels which is regulated by gastric contents Small cells +/- short microvilli gastrin, histamine, cholecystokinin, somatostatin, VIP, substance P STOMACH

Question 26

Small Intestine : Plicae circularis

Answer 26

what : ridge of submucosa & mucosa where : seen in longitudinal sections greatest number in the duodenum

Question 27

Small Intestine : villi

Answer 27

what: projections of the mucosa (0.5mm – 1.5mm long) where: epithelium with a core of lamina propria Longest in the jejunum

Question 28

small intestine : Striated border

Answer 28

what: microvilli on the apical surface of epithelial cells where: ~ 2,000/cell, actin core

Question 29

small intestine mucosa

Answer 29

Simple columnar epithelium * + goblet, paneth and enteroendocrine cells lamina propria * fibroblasts, lymphocytes, plasma cells, eosinophils, macrophages * smooth muscle cells, collagen, vessels * Peyer’s patches in Ileum ONLY muscularis mucosae * thin layer of smooth muscle

Question 30

small intestine submucosa

Answer 30

dense irregular CT * large vessels * Meissner’s nerve plexi * Brunner’s Glands in the Duodenum * Peyer’s patches seen in Ileum lymphoid tissue

Question 31

small intestine - Muscularis externa

Answer 31

Inner layer circular smooth muscle segmental contraction to mix contents peristalsis to move contents Outer layer longitudinally arranged smooth muscle peristalsis contraction Auerbach’s plexus of nerves located between the 2 smooth muscle layers

Question 32

small intestine - serosa

Answer 32

Simple squamous mesothelium Rests on a basement membrane Dense irregular/loose connective tissue Large vessels

Question 33

Enteroendocrine cells

Answer 33

Release hormones * increase pancreatic & gallbladder activity * initiates gastric & intestinal motility * stimulates insulin release * paracrine (local) effects also

Question 34

Paneth cells

Answer 34

o secrete lysozyme for antimicrobial affect to regulate normal flora of small intestine

Question 35

Submucosa of the small intestine : regional variations (duodenum)

Answer 35

Duodenum Brunner’s Glands Sero-mucous secretion pH 8.5 – 9.3

Question 36

Submucosa of the small intestine : regional variations (jejunum)

Answer 36

Dense irregular CT Vessels, fibroblasts

Question 37

Submucosa of the small intestine : regional variations (ileum)

Answer 37

Peyer’s Patches Lymphatic nodules

Question 38

Small Intestine distinguishing histological features

Answer 38

* Plicae circularis * Villi * Paneth cells * Brunner’s glands in submucosa of Duodenum * Peyer’s patches of lymphoid tissue in Ileum