Lecture 2c 16 January 2015 Ingestion Digestion Absorption Metabolism Transport Excretion Common...
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Transcript of Lecture 2c 16 January 2015 Ingestion Digestion Absorption Metabolism Transport Excretion Common...
Lecture 2c 16 January 2015
IngestionDigestionAbsorptionMetabolismTransportExcretionCommon digestive tract problems
Overview of lecture 2c
1) ingestion 2) digestion3) absorption4) transport5) metabolism6) excretion7) regulation of IDATME8) common digestive tract disorders
-dysregulation of IDATME
INGESTION
a) Mouth-open, chew and swallow
b) Tube feeding c) IV and catheter
DIGESTIONa) Sequencing of eventsb) Digestion -process by which food is broken down into absorbable units -anatomy
-function of each of anatomical parts-figure 3-1 Rolfes et al-mechanics
-muscular action of digestion-peristalsis-stomach action-segmentation
http://nutrition.jbpub.com/resources/animations.cfm?id=1&debug=0
-sphincters-secretions of digestion
Fig. 3-1, p. 71
digestive glands/secretions (enzymes)-saliva-gastric – water, HCl and pepsin-proteins-pancreatic juice/intestinal enzymes
carbohydraseslipasesproteases
summary of digestive secretions-pg 74-76
E:\Media\Animations\chapter3\Digestive_Sandwich\0308.html
Absorption
1) define-passage of nutrients from gi tract into blood or lymph
A) simple diffusion-water small lipids/fat solublevitamins
B) facilitated diffusion-fructose/water soluble vitamins
C) active transport-glucose/amino acidsdo not confuse active transport with the transport
discussed below
2) anatomy-goblet cells/crypts/villi and microvilli
Fig. 3-10, p. 79
Transport
defined
getting nutrients, via blood or lymphatic systems,
to where needed (W)when needed (W)in the form needed (F)and in the correct quantities needed (Q)
WWFQ
anatomy of transport
two routes
-blood and lymph
Anatomy BLOOD ROUTE
Heart to artery to capillaries (intestine) to vein to capillaries (liver)–in liver get detoxification and preparation of nutrients for body use-vein to heart from liver for distribution to the rest of the body .
water soluble nutrients and smaller products of fat digestion go this route
Lymph route
Lymph (tissue spaces to blood) intestine to heart directly for distribution to rest of body
-larger fat digestion products and fat soluble vitamins (ADEK)
use this route
E:\Media\Animations\chapter3\Vascular_System\311.html
file:///E:/Media/Animations/chapter3/Vascular_System/311.html
Metabolism
Building up - requires energy
Tearing down- gives energy
Tearing down-provides building blocks to build up
-also leads to excretion
Excretion-in whole or as a metabolite
-urine-protein (urea), minerals, water, carbohydrate, vitamins
-feces-carbohydrates, lipid, vitamins, protein, water, minerals
-sweat-minerals,water-saliva?-minerals?, carbohydrates?,
lipids?, protein?, water?, vitamins?
-breathing-O2 and CO2
Regulation of IDATME-pgs 83-86 Rolfes et al.
-all hinges on homeostasishomeostasis-maintenance of constant internal conditionshomeostasis can be disrupted by physical immaturity,
aging, illness, nutrition
-stomach pH homeostasis – pH 1.5-hormonalregulation-important for digestion
Regulation of IDATME
Digestion regulation
Pyloric sphincter
hold food ready for duodenum duodenum has pH sensors -too acid-close pyloric sphincter
and bicarbonate added to chymemaking chyme neutral and thenpyloric sphincter opens again
why? -pH important for enzyme function
Regulation of IDATME
Digestion regulation continued
hormonal regulation of 3 types of enzymes- type and amount of enzymesfrom pancreas
bile-fat emulsion-amount under hormonal regulation
fat slows peristalsis-hormonal
digestion regulation leads to absorption regulation
leads totransport regulation
Regulation of IDATME
•Ingestion regulates digestion •Digestion regulates absorption•Absorption regulates transport•Transport regulates metabolism (WWFQ)•Metabolism regulates excretion
Common digestive problemschoking- epiglottis-tough meats, hot dogs, nuts, grapes
carrots, hard candies, popcorn and peanut butter
vomiting-cause-gastric irritation -effects are : dehydration
: nutrient loss (salts) : teeth damage if excessive
(bulimia) : aspiration
-solution-replace salts/fluids by oral or IV
diarrhea-cause-infection, drugs, sorbitol, olestra, colitis -effects-if not reversed get dehydration and nutrient loss -solutions-oral or IV replacement of fluid and
nutrients with low fat small mealsand a gradual increase in fibre
Common digestive problemsconstipation-cause-failure to respond to defecation
signal -lack of activity (intestinal muscle tone) -medications -tumours
-solution-eat fibre(eg prunes)- attracts water -drink more water -eat fat- bile produced-attracts water
belching -cause-swallowing air, gallbladder disease or peptic ulcer
-solution-medical treatment of cause
gas-cause-carbohydrate rich diet with partial digestion of fibre ingut and rest goes to bacteria that make gas
-solution-change diet
Common digestive problems
heartburn and acid indigestioncause-acid reflux-anatomical defect
-eat or drink too much -chew too little -smoking
-solution- if not an anatomical defect- eliminate other causes
ulcers-gastric or peptic (duodenal)-cell erosion -cause-not stress or spicy foods -H. pylori story
-AIDS drugs
-solution-avoid pertinent infections
disorders causing excessive gastric acid secretion
treat via- antibiotics
- withdrawl of offending foods
-withdrawal of caffeine or
alcohol on acase by case basis
Next lecture
Carbohydrates-structure and classification
-IDATME of carbohydrate