Physiology 3120 Lecture Notes - Lecture 11: Tandem Pore Domain Potassium Channel, Antihistamine, Exocytosis

3 views5 pages
Woods Lecture 11
-saliva secreted by three salivary exocrine glands to start process of digestion
-also need saliva to be able to taste food as liquefies out flavours and allows swallowing
-also needed to lubricate tongue to be able to talk
Parotid Gland – secretes saliva while eating
-watery w/ amylase to digest starch
Sublingual Gland
-somewhat mucusy saliva w/ little amylase
Submandibular Gland – secretes constantly to lubricate tongue, etc.  thus not just for eating
-very mucusy saliva w/ no amylase
-body of gland made up of CT and myoepithelial cells that contract to push acinar contents into
duct towards mouth
-primary secretion (of saliva) coming from acinar cell initially isotonic
-as primary secretion travels down into duct, ductal/epithelial cells modify it to make secondary
secretion
-use transporters to reabsorb Na/Cl and secreting K/bicarbonate
When saliva flows slowly, cells have enough time for more modification  hypotonic since ions
reabsorbed but water stuck (impermeable cells)
When saliva flows fast, cells have less time for modification  closer to isotonic (important later)
1. Water – saliva needs to be in fluid form
2. Chloride – activates amylase
3. Bicarbonate/phosphate ions – to neutralize acidic food to protect teeth
4. Mucus – lubricate tongue and food to make it easier to swallow
5. Amylase – digests starch
6. Lipase – needs acidic envt to digest fat thus does not start working until food in stomach
-secreted by cells in mouth not salivary glands
7. IgA/lysozyme – detects and breaks down viruses and bacteria/breaks down bacterial cell
walls
-salivary secretion is only secretion in GI tract controlled by mostly neural regulation
-another unique feature is that both PSYN and SYN work together  usually antagonistically
-when both active, get maximal salivary secretion BUT need PSYN to initiate
2. Complex neural mechanisms to close nasal cavity, to close trachea and to contract specific
pharyngeal muscles to push food down further back and into esophagus
find more resources at oneclass.com
find more resources at oneclass.com
Unlock document

This preview shows pages 1-2 of the document.
Unlock all 5 pages and 3 million more documents.

Already have an account? Log in
-all under ANS  not conscious
3. Neurons stimulate muscles along esophagus to push food bolus down
RMR less saliva = less IgA/lysozymes = more prone to infections
-contracts behind bolus to push it forwards while relaxing in front of bolus to allow bolus to get
there
-only initiated if bolus stuck in esophagus  afferent neurons send APs and efferent neurons get
stimulated to initiate secondary peristalsis
-food gets through lower esophageal sphincter to enter stomach  end of esophageal stage
-fundus and body secretes lots of acid and inactive pepsinogen
-antrum secretes hormones
-pylorus=pyloric sphincter keeps bolus in stomach
-pylorostenosis where pyloric sphincter no longer opens  projectile vomiting at 4-6weeks
old
-mostly affects first-born male and life threatening without immediate surgical intervention
-rugae are folds in stomach that increase SA
1. neck since located in upper part of rugae ie: facing stomach lumen
3. Intrinsic factor needs to combine with vitamin B12 for it to be absorbed
1. G cells secrete gastrin into blood that circulates around body and comes back to act on
stomach specifically to stimulate acid production by parietal cells
Unique features of stomach mucosa and muscularis externa:
-rugae are mucosal folds
-pits are invaginations into mucosa that contain stem cells to regenerate enterocytes on surface
-mucus neck cells are enterocytes at top of rugae - secrete mucus layer that protects stomach
wall from acid
-chief and parietal cells are enterocytes further down in pits – secrete acids and enzymes
-body has less circular smooth muscle
-antrum has more longitudinal smooth muscle
-bolus gets mixed with stomach secretions and propelled toward pylorus
-as it gets propelled, pyloric sphincter closes as grinding intensifies in antrum
find more resources at oneclass.com
find more resources at oneclass.com
Unlock document

This preview shows pages 1-2 of the document.
Unlock all 5 pages and 3 million more documents.

Already have an account? Log in

Get access

Grade+
$10 USD/m
Billed $120 USD annually
Homework Help
Class Notes
Textbook Notes
40 Verified Answers
Study Guides
1 Booster Class
Class+
$8 USD/m
Billed $96 USD annually
Homework Help
Class Notes
Textbook Notes
30 Verified Answers
Study Guides
1 Booster Class