Excretory And Digestive System Flashcards
Excretory organs?
Liver: (hydrophobic and large waste)
Skin: sweat (water, urea, ions)
Colon: reabsorption and excretion of waters day ions
Kidney: (hydrophilic waste)
Excretory and homeostatic role of the kidney processes
Filtration
Selective reabsorption
Secretion
Concentration and dilution
Secretion , conc, and dilution occurs mostly where and what hormone control them?
Mostly occurs in DCT and collecting tubules
Controlled by ADH and aldosterone.
Loop of Henle consist of? And what is reabsorbed at each phase
Thin Descending loop - reabsorption of water leaving the filtrate conc
Thin ascending loop- reabsorption of ions
Thick ascending- reabsorption of NACL and secretion of k+ leaving the medulla osmolarity high
Countercurrent multiplier (CCM) and countercurrent exchanger (CCE)
Loop of henle - aims to leave the medulla salty and facilitates the reabsorption of water in the CD. This is how kidney can make urine with more osmolarity in urine that in plasma
CCE- vasa recta( descending peritubular cappilaries)
Glomerulus filtration apparatuses (GFA) - renal regulation of bp and ph
GFA is the link btw the afferent arteries (JG CELLS) and the distal tubules( MACULA DENSA)
Afferent arteries (baroreceptors)- contrl systemic bp by releasing renin when bp is low . Renin lead to release of aldosterone
Distal tubules (chemoreceptors)- contrl filtrate osmolarity ; reduced filtration rate, by activating the JC cells or dilating the afferent arterioles
Ph regulation?
HCO3-
H+
Enzymatic hydrolysis for macromolecules
Triglycerides- 2FA + 1 monoglyceride by lipase
Polysaccharides- diassacharudes by amylase or ptyalin
Dissachrides- monosaccharide by dissachridases
Polypeptide- dipeptide and tripeptide by gastric acidity , pepsin, pancreatic proteases( trypsin and cgemotrypsin)
Diapeptide and tripeptide - aa by peptidases (SI)
Hi lumen layers?
Mucosa (epithelial cell, villi)
Submicosa ( CT)
Muscularis ( circular and longitudinal SM)
Serosa (CT)
Gi epithelium structures?
Basement membrane Apical surface Microvilli Tight junction Basolateral surface
Types of muscles?
Non straited— smooth muscle
Striated — skeletal muscle and cardiac muscle
GI motility contrl is determined by 5 factors?
- Automacity
- Functional syncrium
- Hormonal input
- Enteric NS
- Para.s and s stimulation
Enteric NS
Help to regulate blood flow , peristalsis, movement of fluid in and out of the gut
Divided into
mysentric plexus - found btw the smooth muscles and help regulates gut motility
Submucosa plexus- in the submicosa, regulates enzyme secretion , blood flow, ion and water balance in the lumen
Gi secretion
Exocrine (enzymes)- pancreas( pancreatic Acinar cells), liver, gallbladder, gastric glands, goblet cells
Endocrine (hormones) - pancreas (islet of larngahens) , cells in the wall of gut,
Saliva enzymes?
Silica amylase
Saliva lipase- tiny quantity
Saliva lysozyme- to attack bacteria
Gastric secretions?
Chief cell- pepsin: proteolysis( protein breakdown)
Parietal cells - HCL and IF
G cells- gastrin : stimulates HCL and pepsin secretion by using histamine
Why need for stomach acidity?
- Hydrolysis of protein
2 conversion of pepsinogen to pepsin
- Killing of microorganisms
Pyloric sphincter
Prevent backglow of food from duodenum to stomach and vice versa
By 3 duodenal hormones
- (CCK) mainly
- Secretin
- Enterogastrone
Cholecystokinin (CCK)
Hormone secreted by the deodenum in response to fat in deodenum that prevent the stomach from empty by closing the pyloric spincter , causes pancreas to release enzymes, bile release, -Ce gastric motility (all corporate to deal with fat in deodenum)
Digestion and absorption beginning and end?
Digestion begin in mouth and end in the Jejunum
Absorption begins in the deodenum and end in ileum
Intestinal villus contains?
- Capillaries for absorption to the hepatic portal vein
- Lacteals- for FAt absorption
- Payers patches- collection of lymphocytes 4 protection
Ileum
Absorption of bit b12-IF complex
ReAbsorption of bile acid
Bile acid sequestrants?
Drugs that bind bile acid in the small.i leading to excretion of the bile in feces
Deodenal enzymes? And duodenal hormones?
Enzymes
1.Deodenal enterokinase (enteropeptidase)- activates trypsinogen
- Brush boarder enzymes- enzymes that do their work (hydrolysis of carbs and protein into aa and monosaccharides) on the surface of the brush boarded epithilium e.g dissachridases and petidases
Hormones
1. CCK- pancreas release enzymes, bile release, -Ce gastric motility (all corporate to deal with fat in deodenum)
- Secretin: causes release of HCO3- from pancreas
- Enterogastrone: -ce stomach emptying
