Transcript Slides for Digestion Notes

Digestion: Process of breaking down food molecules so
nutrients can be absorbed
Mechanical Digestion: *teeth  chewing breaks ↓ food into
smaller pieces (prepares for chemical
digestion by ↑ing SA for enzymes to work
in chemical digestion)
*churning of stomach (sm muscles)
Chemical Digestion: Enzymes further break ↓ food particles
so nutrients can be absorbed
4 Layers of Digestive Tract
*Frenulum: attaches
tongue to floor of mouth
Epiglottis: closes off trachea and bolus passed into
esophagus (behind trachea) when you swallow
Salivary Glands: In mouth start chemical digestion of carbs
Pharynx (throat)
Esophagus
and Cardiac Sphincter
cardiac sphincter
Stomach
*
*
Small Intestine: ABSORPTION of
nutrients
Duodenum
1st part of sm
intestine is where
most digestion
takes place
Rest of sm intestine
 absorption
Villi/Microvilli
Of Sm Intestine
↑ SA for
absorption of
nutrients
Liver and Gall Bladder
Lg Intestine:
Fx Absorption of
H2O
jejunum
Peritoneum: Serous moist membrane lines abdominal cavity
& covers organs
(remember Epi membranes  serous, cutaneous, mucous 
connective tissue membranes  synovial
no Epi component
Shiny surface of
the organs is
the visceral
peritoneum;
shiny lining the
abdominal wall
is the parietal
peritoneum
Mesentary: Extension of Parietal Peritoneum
Anchors Sm Intestine to abdominal wall
Greater Omentum: Extension of parietal peritoneum
Envelopes inflamed appendix
CAT
M
E
O
W
Digestion of Carbs: major source of energy
Starts in mouth w/salivary amylase
Sm Intestine: pancreatic & intestinal juices digest starch & sugars
____________ase (enzyme for what it works on)
Amylase  breaks ↓starch & sugars
Maltase  breaks ↓maltose (gal + gal)
Sucrase  breaks ↓ sucrose (glu + fru)
Lactase  breaks ↓ lactose (glu + gal)
* Starches polysaccharides disaccharides monosaccharides
Carbs: preferred energy food
Glycolysis: glucose metabolism (catabolic)
CR: w/ O2 = lots of ATP
Glycogenolysis: glu  glycogen for storage (an anabolic)
Pancreas: Alpha Cells  glucagon hormone
glycogen  glucose ↑’s BS
Beta Cells  insulin hormone
carries glucose across CM ↓BS
Antagonists
Hypoglycemia: low BS vs Hyperglycemia: high BS
Diabetics metabolize fats vs glucose  byproduct ketones
 Ketoacidosis  affects blood pH  diabetic coma
Proteins: Growth & development, repair, enzymes (catalysts)
Can be broken ↓ for energy
Starts in stomach
Enzymes Renin & Pepsin in gastric juice
Sm Intestine: Trypsin in pancreatic juice
Pepsidase in intestinal juice
Fats: store energy (2x more than carbs) impt in cm’s
Saturated,
Unsaturated,
Polyunsaturated
No C=C
1 C=C
>1 C=C bond
Animals
Plants
Solid @ RT
Liquid @ RT
Gastric lipase in gastric juice digests some fat in stomach
Most fat undigested until of sm Intestine
Bile salts (aid enzyme Fx) made in liver stored in gall bladder,
released into duodenum to emulsify fats (mechanical)
Pancreatic enzymes splits fats into glycerol & 3 fa’s
Food Undergoes: Digestion, Absorption (↑ SA) Metabolism
*Metabolism = anabolic + catabolic Rx’s (dehy synth & hydro)
H2O = most of body wt (blood plasma >90% H2O
Minerals: Inorganic & req’d by body
(to make Hgb, DNA, RNA, ATP)
Ca: teeth, bones, nerve, muscle fx
Vitamins: Help enzymes fx
K & some B complex made in liver
D made in skin (w/ sunlight)
A, D, E, K, fat soluble & stored in fatty tissue
C & B H2O soluble, need daily