21539404
Description
Flashcards by Evian Chai, updated more than 1 year ago
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Created by Evian Chai
over 4 years ago
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| Question | Answer |
| What 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 |
| What plexuses innervate the GI tract? | 1. Myenteric plexus for muscle contraction (ANS) 2. Submucosal plexus for sensory function and local response to stimuli |
| What is the type of epithelium in the oesophagus? | Protective stratified squamous |
| What type of epithelium is in the gut+duodenum? | Secretory simple epithelium |
| What type of epithelium is in the small intestine to colon? | Absorptive simple columnar |
| What type of epithelium is in the rectal region? | Protective |
| Is the oesophagus controlled voluntarily or involuntarily? | Top 1/3 is voluntary, middle 1/3 is mixed, bottom 1/3 is involuntary |
| What is the purpose of the submucosal glands in the oesophagus? | Lubrication of food |
| What happens when muscles at the gastro-oesophageal junction relax? | Acid reflux |
| What 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 |
| What distinguishes the muscularis externa of the stomach to the basic structure? | Has 3 layers (oblique, circular, longitudinal) for spiral churning |
| What are rugae? | Muscle folds that catch food particles and move them around |
| Where are gastric pits and their glands located in the stomach? | On top of muscle cells |
| Which cell is found in the Isthmus (top) of the gastric gland and what does it secrete? | Parietal cell, HCL |
| Which cell is found in the neck of the gastric gland and what is their function? | Stem cells |
| Which 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 |
| Why does the stomach not digest itself? | Surface epithelial cells secrete bicarbonate ions to create neutral mucus layer |
| What are the three parts of the small intestine? | 1. Duodenum 2. Jejunum 3. Ileum |
| What does the duodenum and the Brunner's glands in it do? | Digestion/absorption with simple villi Produce alkaline mucous to neutralise food |
| What 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 |
| What 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 |
| What 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 |
| Does the colon contain enterocytes/goblet cells? | Yes, for H20 absorption/lubrication |
| What is the recto-sphincter for? | Voluntary defection |
| How does the epithelium cell type change across the colon? | Changes from glandular structure to nonkeratinsing stratified squamous to keratinised stratified squamous |
| What are the functions of saliva? | 1. Lubricates 2. Moistens 3. Digests w amylase/lipase 4. Antiseptic |
| What 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 |
| What type of exocrine secretion occurs with salivary glands? | Merocrine secretion |
| What is the structure of the salivary gland? | Branched acinar structure |
| How 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 |
| In 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 |
| What 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 |
| What are the 4 functions of the tongue? | 1. Manipulation of food 2. General sensory reception 3. Special sensory reception (eg. taste) 4. Speech |
| What 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 |
| What 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 |
| How does the final 1/3 of the tongue differ from the first 2/3? | Smooth oral epithelium over lymphoid tissue |
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