Salivary glands, oesophagus, and Stomach micro anatomy Flashcards Preview

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Flashcards in Salivary glands, oesophagus, and Stomach micro anatomy Deck (44):
1

Parasympathetic and Gut activity?

Activates and enhances gut activity

2

Sympathetic and Gut activity?

inhibits gut activity

3

What are the layers of the GI tract?

1) Mucosa - epithelium, lamina propria and muscularis mucosae
2) Submucosa
3) Muscularis Externa
4) adventitia/Serosa

4

Purpose of epithelium?

Protection (multiple layers)
Secretion
Absorbtion

5

Purpose of lamina propria

Support
1) Mechanical Support - collagen
2) functional support - BV, nerves, lymphatics

6

Purpose of Muscularis Mucosae

Movement independent of peristalsis

7

Purpose of Submucosa?

Same as lamina propria

8

Why is the lamina Propria loosely arranged?

to allow for the expansion of a bolus

9

How is the muscularis externa arranged? What is the exception of this?

Inner circular and outer longitudinal
exception stomach

10

What type of muscle is the muscularis externa? What is the exception of this?

Smooth muscle (involuntary).
Exception: Upper 1/3 oesophagus
internal anal sphincter

11

Whats the difference between adventitia and serosa?

Adventitia: outermost CT covering any organ, vessel or other structure.

Serosa (visceral peritoneum) slippery outer covering for the gut tube; two layered, with the outer mesothelium sitting on a bed of CT

12

Intra peritoneal

Organs totally suspended. These are covered in serosa (simple squamous mesothelium)

13

Retroperitoneal

lined with serosa on anterior surface only ('outside peritoneal cavity')
Posterior surface is adventitia

14

how much Serous Fluid do we produce daily?

7L

15

Submucosal plexus is also called?

Meissner's plexus

16

Sphincters. What layer are they formed by

gate keepers that control the volume/timing/flow if substances from one region to another.
Thickening of the IC

17

Ascites

Caused by cirrhosis/liver damage, heart failure
-accumulation of fluid in the peritoneum, abdominal swelling, distortion of visceral organs
-can be drained

18

Peritonitis

-inflammation of the peritoneum > impaired function

19

What determines the composition of the secretions

The proportion of Serous acinar (dark) and mucus acinar (light) whether it is serous/watery or mucous/sticky

20

% of contribution and types of acini in the salivary glands

Parotid (~25%) - serous acini (dark cells) > watery

Submandibular (~70%) - mixed (dark and light) > serous + mucus

Sublingual (~5%) - mixed (dark and light) > serous + mucus

21

Draw and describe a serous acinus

-central, darkly staining nuclei
-Mitochondria perpindicular to the basal surface
-Zymogen granules in the apical cytoplasm (predominate AMYLASE)
-myoepithelial cells surround the base of acini

22

Myoepithelial cell

modified contractile epithelia. Squeeze acital secretion into lumen.
-in BOTH serous and mucus acinus

23

Draw and describe a mucus acinus

-flattened, peripheral nucleus
-mucus granules in the apical cytoplasm (flatten nuclei)
-myoepithelial cells around base of acinus

24

Striated ducts are... How are they striated and whats this for?

Intralobular ducts.
-aligned mitochondria in the basal infoldings of the cell give striated appearance
-this is because they have increased METABOLIC ACTIVITY and ACTIVE TRANSPORT

Function is to exchange Na+ and Cl- for K+ and HCO3-

25

Composition of saliva

99% water
1% ions, buffers, enzymes etc

26

Lubrication function of saliva

Carb-rich glycoproteins (mucins): slippery molecules of mucus
also has a protective function as they prevent bacterial adhesions (hard to attach)

27

Protection Function of the saliva

PREVENT:
-Bacterial adhesions & secretions (usually acidic)
-vomit (acidic)

-Bicarbonate ions (counteract acid (gastric to an extent))

-Lysozyme (breakdown bacteria cell walls)
-Lactoferrin (fight iron dependent bacteria)
-Immunoglobulin A (fight genetic infection/virus)

28

Why do we get a huge saliva influx before vomiting?

Protective reflux reaction to ensure the alkaline saliva buffers the acidic vomit

29

Digestion Function of Saliva

AMYLASE: (pH 4-11), starts sugar/carb BD into monomers. (as sugars are good site of bacterial growth this decreases potential growing sites!)

LIPASE (pH 4): breakdown fats, more active in stomach as pH lower

Kallikrein: protease, cleaves another proenzyme > increased blood flow and bloody supply to sustain demand for metabolism whilst eating

30

PSNS

accelerates secretion > lots of watery saliva
myoepithelial cells contract
-increased blood flow

31

SNS

small amount of viscous saliva containing high enzyme concs
-less volume = dry mouth feeling
BVs constricted

32

Why do meth users have such bad teeth

destroy salivary gland > destroy protective function!

33

Function of Oesophagus

rapid transport (PS) of the food bolus. straight ~25cm tube, thick muscular wall, protective lining. Collapsed outline with folds of submucosa when empty (loosely packed)

34

Epithelium of oesophagus

thick sacrificial stratified squamous epithelium (6-8 layers). non-keritinised
as it approaches stomach >> cuboidal/columnar

35

Muscularis mucosae of oesophagus

absent/rare upper but developed near stomach, not defined, discontinuous in places.
Allows for mucosa movement independent of peristalsis

36

Are glands present in the oesophagus

yes

37

Muscularis externa

2 coats, not always circular and longitudinal, irregular areas.
upper 1/3: skeletal (striated)
middle 1/3: skeletal & smooth
lower 1/3: smooth (poorly preserved)

38

Covering of oesophagus

adventitia (except 1-2cm)

39

Chronic Oesophagitis

Often caused by GORD > inflammation
-stratified squamous only protective of mechanical abrasion
-chronic exposure can cause Barretts syndrome (precursor to oesophageal cancer)

40

In the body/Fundus

Parietal Glands
-HCl
-Intrinsic factor
-pepsinogen
-somatostatin

41

Rugae are

transient folds that come and go (less when full)

42

Four anatomical regions

cardia: mucus (bufferzone)
fundus
body: parietal glands
pylorus: mucus (bufferzone

43

Pyloric Glands

-Mucus**
-pepsinogen
-gastrin
-somatostatin

44

Muscularis externa layers of the stomach

Inner oblique
middle circular
outer longitudinal