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24 Cards in this Set
- Front
- Back
give an example of:
- mucous secretion - serous secretion - mixed secretion |
- esophageal [mucin]. Gen. spherical.
- pancreas [protein/enzyme: watery] Gen. tubular - salivary: serous demilunes [mucous acini capped by serous cells] [artifact] |
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Structure of exocrine gland: [3]
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1. myoepithelial cell: contractile cell between gland cell + basal lamina of epithelium. squeeze secretory unit from centre to acinus
2. acinus→intercalated duct→intralobular→interlobular→lobar→main 3. CT/fibroblast/lymphocytes between lobules |
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Describe structure of salivary glands [2]
1. Major - give an example[3] 2. Minor - give an example[5] |
- compound tubuloacinar
- basic secretory unit: acinus [serous, mucous, mixed] 1. Major salivary glands: paired gland, long duct emptying into oral cavity *surround by capsule of mod. dense CT *CT septa divide glands into lobes/lobules: contains larger BV + excretory ducts - Parotid [serous]: below+in front of ear - submandibular [mixed]: under floor of mouth - Sublingual [mucous]: floor of mouth ant. to submandibular gland 2. Minor salivary gland: submucos of diff. parts of oral cavity - buccal, lingual, labial, molar, palatine |
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Innervation of salivary gland [2]
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1. Sympathetic (Cervical symp. chain)
- slow rate of secretion - high in protein/consistency (thick saliva) 2. Parasympathetic - copious secretion - low consistency, more watery |
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Ducts of salivary gland
1. [2] 2. [4] 3. [3] |
1. Intercalated: intralobular, from acinus
- prominent in watery serous gland [parotid] - difficult/short in mucous secretory [sublingual] 2. Striated: - intralobular [in the parenchyma of gland] - basal infolding + long. arranged mitochondria - absorption (Na+) & secretion (K+, HCO3-) - striated duct ø exceeds secretory acinus ø *1&2 modify serous by absorbing/secreting: ax w. serous, not mucous, acini* 3. Excretory - in interlobular + interlobar CT, empty → oral cavity - small excretory duct (simple cuboidal): change to pseudostrat col. or strat cuboidal/squamous as ↑size - Stensen's (parotid) + Wharton's (submandibular) travel in CT of face & neck respectivley |
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describe structure of parotid glands [3]
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- *Lots of adipose tissue*
- completely serous - largest among major salivary gland, paired |
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describe structure of submandibular glands [2]
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- large, paired
- mixed/predominantly serous in human |
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describe structure of sublingual glands [3]
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- smallest among major salivary glands
- some of mucous acini ax w. serous demilune - mixed, mostly mucus-secreting in humans |
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saliva
- how much is secreted per day [1] - composition [3] |
- 1200 mL produced
- water, - various proteins, electrolytes: - principle enzymes: lysozymes, a-amylase |
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Functions of saliva
- digestion [4] - protection [5] |
Digestive:
- aid swallowing - dissolve food → can be chemically tasted - buffering (high conc. of bicarbonate ions) - digest carbohydrates (a-amylase) Protective: - moisten oral mucosa - control bacteria flora in oral cavity [lysozyme] - tooth development/maintenance (Ca, phosphate) - IgA [plasma cells in CT surround secretory acini] - Dimeric receptor for IgA: secretory glycoprotein inserted on basal membrane [receptor-mediated endocytosis→acini cells→apical membrane→secreted] |
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Structure of pancreas [3]
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- elongate gland: head, body, tail
- Exocrine: *synthesize/secrete digestive enzyme into duodenum *proteolytic peptidase (trypsin, chymotrypsin), a-amlyase, lipase, nuclease - Endocrine (islets of Langerhans) *insulin, glucagon |
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Structure of exocrine pancreas [1]
- divided into [2] |
- serous glands:
1. Secretory unit 2. Ductal system |
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Secretory unit structure [4]
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1. acinar or tubuloacinar
2. basophilia in basal cytoplasm: *rER, free ribosome [high level of protein synthesis] 3. acidophilic zymogen granules, apical cytoplasm *proenzymes (Trypsinogen, chymotrypsinogen), activated only in SI by enterokinase at microvilli - trypsinogen→trypsin→convert other inactive enzyme & digest protein 4. well-developed Golgi apparatus |
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Ductal system of exocrine system [4]
- intercalated duct [2] |
1. Intercalated duct (Squamous) →
intralobular duct (cuboidal, no striated duct) → Main pancreatic duct (long axis of pancreas) → Accessory pancreatic duct (head of pancreas) 2. Intercalated duct start in acinus - Centroacinar cell: duct cell within acinus [pale-stain] - Intercalated duct: add HCO3-, H2O into exocrine s. |
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What controls pancreatic exocrine secretion [3]
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1. Hormone: secretin, CCK [stim by acidic chyme in duodenum]
2. PSNS: activity of acinar + centroacinar cells 3. SNS: regulate pancreatic blood flow |
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Function of exocrine pancreas
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Secrete pancreatic juice w. digestive enzyme for:
- Protein: trypsin, chymotrypsin - Carbohydrate: a-amylase, maltase - Lipid: lipase |
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Endocrine pancreas
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- regulate BG levels
Islets of Langerhan (1-2% pancreas) 1. A (alpha, 15-20%; glucagon) 2. B (beta, 70%: insulin) 3. D (delta, 5-10%, somatostatin) 4. PP (pancreatic polypeptide) 5. D-1 (VIP) 6. EC (secretin, motilin, substance P) |
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STructure of liver [3]
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- largest gland in body (1.5 kg, 2.5% body weight)
- endoderm evagination from wall of foregut - hepatocyte: cellular cords |
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FUncitons of liver [9]
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1. Protein synthesis (albumin, lipoprotein, glycoprotein, prothrombin, nonimmune a & b-globulin)
2. Vit A/K: Uptake/store/distribute nutrient (Ito cell) 3. BG: Control level 4. VLDL: Regulate circulating level 5. DETOX: degrade, conjugate toxic/drugs (sER) 6. IRON: store/metabolise/homeostasis 7. BILE: synthesis/secretion [1.1 l/day] 8. Remove bilirubin 9. Endocrine (vit D→25-hydroxycholecalfierol, T4→T3) |
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BS of liver
- incoming [2] - pathway [4] |
1. 75% hepatic portal vein (venous)
2. 25% hepatic artery from celiac trunk (oxygenated) →sinusoids between hepatocytes →central vein →sublobular vein →hepatic vein→IVC |
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ORganization of liver [4]
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1. Liver lobule:
classic lobule, portal lobule, liver acinus 2. Classic lobule [less prominent in human liver] - central vein at center, surr. by 5/6 portal area at angle of hexagon - anastomosing plate of hepatocyte [1 cell thick] go radially out from vein. separated by sinusoid - blood flows from periphery to central 3. Portal lobule - based on exocrine function [bile secretion]: - portal area at center of lobule [bile drainage] - Triangular structure: border~imaginary line between 2 central vein 4. Liver acinus [smallest functional unit of liver] - correlation between perfusion, metabolic activity, liver pathology - diamond-shape |
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Sinusoids:
- structure [4] - function of Ito cells [2] |
- venous channel between cord of liver cell
- blood from portal area → central vein - lined by incomplete walls [endothelium, Kupffer cell: mononuclear phagocytotic system: break down rbc] - perisinusoidal space (of Disse): site of exchange materials between blood + liver cell Ito cell: (hepatic stellate, in perisinusoidal space) - store vit A, - myofibroblast→fibrosis [collagen I, III] |
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Histo features of hepatocyte
1. feature [1] 2. Cytoplasm [1] 3. organelles [5] 4. deposits [3] |
Anastomosing cell plates of liver lobule [1 cell thick], long-lived (5 months)
1. binucleation is common 2. hepatocyte cytoplasm generally acidophilic 3. Organelles - ext. sER: enzymes→degrade/conj. toxin, syn. chol. & lipid). Hypertrophy induced by alcohol & drugs - Basophilic regions (rER), - mitochondria, - small Golgi complex, - peroxisomes (H2O2, catalase) 4. Deposit of glycogen, lipid, lipofusin pigment |
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Gall bladder:
- structure [2] - function [1] |
S:
- simple columnar mucosa + folding - no muscularis mucosae, submucosa F: concentrate + store bile |