announcements second exam: wednesday, april 22nd material covered: bone, muscle, nerve &...
TRANSCRIPT
ANNOUNCEMENTS
SECOND EXAM: Wednesday, April 22ndMaterial Covered: Bone, Muscle, Nerve & Circulatory, Lymphatic, & Urinary Systems
REVIEW SESSION TODAY, 4/21 6-7PM ISB 364
LAB PRACTICAL RESCHEDULED: April 28, 29Material Covered: Urinary, Exocrine, & Endocrine Systems, Digestive System & Accessory Organs, and Lymphatic System and Reproductive Systems.
Final Exam: May 18th 1:30 PM in Morrill 203
LAB SCHEDULE
Week of April 20: Work in lab group to, choose organs, complete frozen sections, design immunohistochem. Experiment.
Week of April 27: Lab Practical and learn to section embedded material.
Week of May 4: Immunohistochemistry. Complete sectioning & staining of embedded material.
In class, May 11: Share results, discuss interpretation.
May 18: Lab Project report due at Final Exam.
Anatomy of the Stomach
3 regions:
Cardiac
Pyloric
Fundic
Rugae: longitudinal folds or ridges on inner surface
Each stomach region
has distinctive glands.
•Cardiac glands
•Pyloric glands
•Fundic glands
-gastric pits
-isthmus cell replication
-neck
-base or fundus
Anatomy of the Small Intestine
3 components: Duodenum, Jeunum, Ileum
- Plicae circularis- Villi- Microvilli
- Simple columnar epithelium
Secretion / Digestion / Absorptionepithelial cells and associated glands salivary glands pancreas gall bladder stomach small & large intestine
Secretions include: antibodies: IgA lubricants hydrochloric acid digestive enzymes hormones water
Secretion / Digestion / Absorption
- initiated in mouth- stomach lumen- completed in small intestinal lumen
- aided by HCl from stomach- amylase from saliva & stomach- pancreatic enzymes- enzymes in glycocalyx of small intestine- aided by bile from gall bladder
Lubrication: Mucous Secretions
Esophagus- Lubrication and protection from regurgitation of acidic stomach contents
Stomach- surface mucous cells; mucous protects from abrasion, contains bicarbonate; protects mucosa from acidic stomach contents (chyme)
Small Intestine- goblet cells, # increases from duodenum=> ileum
Large Intestine- goblet cells, # increases toward rectum
Mouth Stomach Small Large Intestine
Intestine
Carbohydrate
Protein
Lipids
Nuclei Acids
Digestive Secretions Digestive Secretions from Pancreas
Absorption Bile from gall bladder
Specialized Cells for Stomach Secretion
Surface Mucous Cells: gastic pit and neck of gastric gland
PAS stain for carbohydrates
millette.med.sc.edu/Lab%201%20pages/introduct...
Specialized Cells for Stomach SecretionParietal (Oxyntic) Cells:- neck & deep parts of fundic glands
- release HCl and intrinsic factor (B12 absorption)
- large
- triangular
- acidophilic
Parietal (Oxyntic) Cells
HCl Synthesis: H+ and Cl- ions pumped into intracellular canalicular system, HCl formed
http://www.mfi.ku.dk/ppaulev/chapter22/images/22-10.jpg
Specialized Cells for Stomach Secretion
Chief Cells: deep in fundic glands, protein-secreting, lots of RER, basophilic, zymogen granules
Secrete pepsinogen HClPepsinogen--------->
Pepsin
Specialized Cells for STOMACH Secretion
Enteroendocrine cells: small - more common in gland base - pale, vesicles don’t fix well - may not reach lumen, but sample lumenal contents with microvilli -release variety of hormones into blood
Small IntestineIncreased Surface Area:Plicae circularis, Villus, Intestinal Gland (Crypts of Lieberkuhn)
Villus: Capillary Lacteal (lymphatic capillary) Smooth muscle
Specialized Cells of the Small Intestine
Enterocytes (intestinal absorptive cells)
Paneth cells- secrete antimicrobial substances
Enteroendocrine cells- release hormones
M cells- dome cells cap lymphatic nodules
Goblet cells- mucous secreting
Enterocytes (intestinal absorptive cells)
Tall columnar cells
Microvilli=>striated border
Epithelial specializations-Terminal web- Tight junctions
Secrete Digestive Enzymes
Paneth Cells
- base of intestinal glands- large- intense acidophilic granules- phagocytose bacteria- secrete lysozyme- digests bacterial cell wall
Large Intestine
Simple columnar epitheliumAbsorption of water and electrolytes
Columnar absorptive cellsCrypts of LieberkuhnGoblet cells
www.kumc.edu/.../histoweb/gitract/gi21.htm
Secretion / Digestion / Absorption
- Requires coordination of secretion and motility with ingestion
NERVOUS AND HORMONAL SIGNALS
Secretion / Digestion / Absorption
- Requires coordination of secretion with ingestion
NERVOUS AND HORMONAL SIGNALS
Release of saliva
Release of digestive enzymes
Release of HCl
Release of bile from gall bladder
Motility of gastrointestinal tract
Secretion / Digestion / Absorption
What signals might trigger release of
hormones and digestive enzymes?
Gastrin secretion: release from stomach enteroendocrine cells (G cells) is stimulated by
1) peptides and amino acids in stomach lumen2) distention of stomach wall3) sensory inputs --> neural innervation (GRP)
- Parietal cells have gastrin receptors
GASTRIN RELEASE
HCl RELEASE
PEPSIN ACTIVATION
PROTEIN DIGESTION
Regulation Parietal Cell HCl secretion
http://www.uwgi.org/gut/stomach_03.asp
Gastrin produced by G cell
HCl produced by parietal cell
Choleocystokinin (CCK): hormone released from enteroendocrine cells of small intestine is stimulated by presence of H+, amino acids, and fatty acids
- Pancreatic cells have CCK receptors**(may act through neurons innervating the pancreas in humans)
CCK RELEASE (INTESTINAL ENDOENDOCRINE CELLS)
PANCREATIC DIGESTIVE ENZYME RELEASE
DIGESTION OF CARBOHYDRATES, PROTEINS, LIPIDS IN SMALL INTESTINE
Choleocystokinin (CCK)
-Gall Bladder smooth muscle cells have CCK receptors
CCK RELEASE (INTESTINAL ENDOENDOCRINE CELLS)
GALL BLADDER CONTRACTION
RELEASE OF BILE INTO LUMEN OF SMALL INESTINE
FACILITATED DIGESTION OF LIPIDS