Flashcards
BMS13-1054 Histology of the GI tract
Cards in this deck (36)
- 1What are the 5 parts of the basic structure of the GI Tract? (outside in)1. Adventitia/Serosa (connective tissue)
2. Muscularis Externa w outer longitudinal/inner circular layer)
3. Submucosa (connective tissue)
4. Mucosa (epithelium):
-Thin muscle layer
-Lamina propria (elastin)
5. Lumen - 2What plexuses innervate the GI tract?1. Myenteric plexus for muscle contraction (ANS)
2. Submucosal plexus for sensory function and local response to stimuli - 3What is the type of epithelium in the oesophagus?Protective stratified squamous
- 4What type of epithelium is in the gut+duodenum?Secretory simple epithelium
- 5What type of epithelium is in the small intestine to colon?Absorptive simple columnar
- 6What type of epithelium is in the rectal region?Protective
- 7Is the oesophagus controlled voluntarily or involuntarily?Top 1/3 is voluntary, middle 1/3 is mixed, bottom 1/3 is involuntary
- 8What is the purpose of the submucosal glands in the oesophagus?Lubrication of food
- 9What happens when muscles at the gastro-oesophageal junction relax?Acid reflux
- 10What are the three parts of the stomach, and functions of their cells?1. Fundus
- HCL producing cells turn material entering acidic
2. Body
-Primary site of digestion, cells produce enzymes
3. Pylorus
-Mucus producing cells lubricate food for passage into small intestine
- 11What distinguishes the muscularis externa of the stomach to the basic structure?Has 3 layers (oblique, circular, longitudinal) for spiral churning
- 12What are rugae?Muscle folds that catch food particles and move them around
- 13Where are gastric pits and their glands located in the stomach?On top of muscle cells
- 14Which cell is found in the Isthmus (top) of the gastric gland and what does it secrete?Parietal cell, HCL
- 15Which cell is found in the neck of the gastric gland and what is their function?Stem cells
- 16Which cell is found in the base of the gastric gland and what does it secrete?Secretory cells (peptic, neuroendocrine, neckmucous, parietal)
Secrete mucus, pepsin, HCL, Vit B12, gastrin - 17Why does the stomach not digest itself?Surface epithelial cells secrete bicarbonate ions to create neutral mucus layer
- 18What are the three parts of the small intestine?1. Duodenum
2. Jejunum
3. Ileum - 19What does the duodenum and the Brunner's glands in it do?Digestion/absorption with simple villi
Produce alkaline mucous to neutralise food - 20What does the Jejunum/Ileum do? What are its unique features?Absorption
1. Villi/microvilli increase SA, richly vascularised
2. Plicae Circulares (folds in mucosa) increase SA
3. Lacteals take away fats in chylomicrons
4. Peyer's patches are small lymphocytes for immunity - 21What are the four cells in the small intestine epithelium and what do they do?1. Enterocytes for absorption via microvilli
2. Goblet cells for mucus
3. Crypts contain stem cells at base of villus
4. Paneth cells secrete antibacterial proteins
- 22What are the three ways the colon differs from the rest of the GI tract?1. No villi
2. V. thick muscularis externa with discontinious outer layer
- SM has three layers
3. Glands for pumping H20 across+pumping mucus - 23Does the colon contain enterocytes/goblet cells?Yes, for H20 absorption/lubrication
- 24What is the recto-sphincter for?Voluntary defection
- 25How does the epithelium cell type change across the colon?Changes from glandular structure to nonkeratinsing stratified squamous to keratinised stratified squamous
- 26What are the functions of saliva?1. Lubricates
2. Moistens
3. Digests w amylase/lipase
4. Antiseptic - 27What are the three main salivary glands and their secretions?1. Parotid: furthest, serous secretion
2. Submandibular: mixed secretion
3. Sublingual: base of oral cavity, mucous secretion - 28What type of exocrine secretion occurs with salivary glands?Merocrine secretion
- 29What is the structure of the salivary gland?Branched acinar structure
- 30How do serous/mucous secreting cells differ in terms of staining and what they produce?Serous: dark stain, produce protein enzymes eg. amylase
Mucous: pale stain, produce thick vicious mucous - 31In the salivary gland what is the function of the myoepithelial cell? Which system is it controlled by?Processes wrap around acinus, contract to expel enzymes/mucous
Controlled by the SNS - 32What are the three ducts in the salivary gland and what are their functions?1. Intercalated duct: secretions exit from here, merge into 2 and 3
2. Striated Duct: Na+/Cl- ions reabsorbed in exchange for K+/HCO3- to create HYPOTONIC saliva
3. Excretory duct: double layer of cuboidal epithelial cell for excreting saliva - 33What are the 4 functions of the tongue?1. Manipulation of food
2. General sensory reception
3. Special sensory reception (eg. taste)
4. Speech - 34What orientation is the skeletal muscle in the first 2/3 of the tongue?All orientations to allow movement in all directions. Interspersed with minor salivary glands
- 35What are the three types of papillae on the tongue?1. Filiform: majority, keratinised spikes
2. Fungiform: Scattered, richly vascularised, taste buds
3. Circumvallate: taste buds at final part of tongue. Contain glands of Von Ebner: salivary glands - 36How does the final 1/3 of the tongue differ from the first 2/3?Smooth oral epithelium over lymphoid tissue
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- Description
- LOs are to: - Demonstrate an understanding of the general layout/structure of the gut - Describe how this basic layout is modified is the oesophagus, stomach, small/large intestines to fit their function - Understand the structural organisation of salivary glands to appreciate primary secretion and the subsequent modification of that secretion - Understand the structure of the tongue to appreciate its functional motility
- Created by
- Evian Chai
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