Please note that only the online course syllabus version is the official version. Please check the online version periodically to make sure that you have the most recent information.

 

Final Exam

-3 hours 120 multiple choice (all lectures after 13 February to the last lecture of the course inclusive)

-4 short answer Questions (15 points each) (all lectures for course)

Lecture 3

INGESTION/DIGESTION/ABSORPTION/TRANSPORT/METABOLISM/EXCRETION

12 JAN. 2015

   

Overview of lecture 3

1) INGESTION2) DIGESTION3) ABSORPTION4) TRANSPORT5) METABOLISM6) EXCRETION7) REGULATION OF IDATME

   

INGESTION

•mouth- chewing and swallowing

•oral or nasal tube

•intravenous

DIGESTION-process by which food is broken down into absorbable units

-muscular action of digestion-peristalsis-stomach action-churning-segmentation –small intestine-sphincters-opening and closing valves

http://nutrition.jbpub.com/resources/animations.cfm?id=1&debug=0

-secretions of digestion

Fig. 3-1, p. 71

DIGESTIVE GLANDS AND THEIR SECRETIONS (ENZYMES)

-saliva-gastric – water, HCl and pepsin-proteins-pancreatic juice/intestinal enzymes

carbohydraseslipasesproteases

file:///D:/Media/Animations/chapter3/Digestive_Sandwich/0308.html

Link only available in class

ABSORPTIONI) DEFINE-passage of nutrients from gi tract into blood or lymph

A) simple diffusion-water, small lipids/fat soluble vitamins

B) facilitated diffusion-fructose/water soluble vitamins

C) active transport-glucose/amino acids do not confuse simple and facilitated diffusion or active transport with the transport discussed below

II) ANATOMY-goblet cells/crypts/villi and microvilli

Fig. 3-10, p. 79

TRANSPORT

defined

getting nutrients, via blood orlymphatic systems, to where needed, when needed, in the form needed and in the correct quantities needed.

WWFQ

ANATOMY OF TRANSPORT

TWO ROUTES

-BLOOD AND LYMPH

ANATOMY OF TRANSPORT 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

ANATOMY OF TRANSPORT 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

file:///D:/Media/Animations/chapter3/Vascular_System/311.html

Link only available in class

METABOLISM

collection of all the reactions and their regulation that go on in the body

constant anabolism and catabolism

METABOLISM

ANABOLISM – BUILDING UP eg -amino acids to protein into muscle

-glucose into glycogen-(carbohydrate storage)

-fatty acids into triglycerides (fat storage)

METABOLISM

CATABOLISM- TEARING DOWN

eg -muscle to protein to amino acids

-carbohydrate (glycogen into glucose)

-triglycerides into fatty acids

METABOLISM

ANABOLISM AND CATABOLISM

-assisted by vitamins, minerals

-water used in some catabolic reactions to split molecules

-water formed by catabolism sometimes

-water formed in some anabolic reactions

Fig. 10-13, p. 347

Fig. 10-13, p. 347

Fig. 10-13, p. 347

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-all hinges on homeostasis- define-

-maintenance of constant internal conditions

-can be disrupted by physical immaturity, aging, illness, nutrition

REGULATION OF IDATME

INGESTION

FOOD INTO BODY- demanded by hunger signals (really metabolic signals) indicating dropping supplies of nutrients

INGESTION REGULATION LEADS TO DIGESTION REGULATION

REGULATION OF IDATME

DIGESTION

-e.g. stomach pH homeostasis – pH 1.5

hormonal/neuronal regulation- -important for digestion

REGULATION OF IDATME

Digestion regulation continued 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

Fig. 3-1, p. 71

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

-also neuronal regulation of peristalsis

-digestion regulation leads to absorption regulation

REGULATION OF IDATME

Absorption (transport across the small intestine into blood or lymph)

-simple diffusion, facilitated diffusion, active transport

REGULATION OF IDATME

ABSORPTION-simple - move with concentration gradient

(regulation- high in small intestine and low on other side) – e.g. water and small lipids go across this way

-facilitated - move with concentration gradient- high in small intestine and low on

other side-presence of carrier (regulation -amount and activity

of carrier)- e.g. fructose and water soluble vitamins go across this way.

REGULATION OF IDATME

ABSORPTION continued -active - move against a concentration gradient

low in small intestine and high on other side - a carrier and energy required (regulation-amount and activity of carrier and

sufficient energy) -e.g. calcium, amino acids and glucose go across

this way.

REGULATION OF IDATME

ABSORPTION REGULATION LEADS TO TRANSPORT REGULATION

REGULATION OF IDATME

Metabolism -enzymes run the show -enzymes in humans are proteins

(always) that allow reactions to go faster than they would without the enzymes

-supply of and demand for metabolic products control enzymatic rates

-high demand with low supply leads to faster enzymatic rates

-low demand with high supply leads to slower enzymatic rates

-metabolism regulation leads to excretion regulation

REGULATION OF IDATME

EXCRETION

-dumping of metabolic waste products -primarily done by liver and kidneys and intestine

ultimately regulates ingestion since retention of metabolic waste products variously upsets metabolism and may make one feel bloated ornauseous with possible vomiting

Regulation of IDATME• ingestion regulates digestion• digestion regulates absorption• absorption regulates transport• transport regulates metabolism• metabolism regulates excretion• excretion regulates ingestion

So we have now gone full circle

   

Summary of lecture 31) INGESTION2) DIGESTION3) ABSORPTION4) TRANSPORT5) METABOLISM6) EXCRETION7) REGULATION OF IDATME

•NEXT LECTURE - 14 JANUARY- Canada’s food guide and DRIs, Food labelsSix dietary principles, Physical activity guidelines