DIGESTIVE SYSTEM

http://www.youtube.com/watch?v=Z7xKYNz9AS0

http://www.youtube.com/watch?v=qyJx_UVEgQI&feature=related

◦Extends from mouth to anus, and consists of the oral cavity, pharynx, esophagus, stomach, small intestine, and colon.

◦Where does digestion take place?

Teeth Tongue Salivary

glands Liver Gallbladder Pancreas

◦Enamel:

◦Dentin:

◦Pulp cavity:

◦Periodontal membrane:

◦Crown:◦Root:

Made of: Nerves: Papillae Swallowing:

◦Step 1:◦Step 2:

◦Salivary glands:

◦Salivary amylase:

◦Lysozyme:

Food movement Reflex:

_______________ Swallowing:

◦ Pharynx constricts◦ Breathing pauses◦ Soft palate elevates

to block nasopharynx

◦ Larynx elevates◦ Epiglottis closes◦ Esophagus starts

peristalsis

Peristalsis LES (lower

esophageal sphincter) or “cardiac sphincter”

◦Mucosa: Location: Function:

◦Submucosa: Location: Function:

◦External muscle layer: Location: Function: 2 layers:_____ & ______

◦Serosa: Location: Function:

Visceral Peritoneum Parietal Peritoneum Mesentery

http://www.youtube.com/watch?v=SKP1q-xpooo

Location: Structure: Function:

◦Cardiac orifice◦Fundus, Body,

Pylorus◦Rugae◦External

muscle layer ◦Pyloric

sphincter◦Chyme

◦Gastric pits◦Mucous cells◦Chief cells◦Parietal cells Proton pumps

◦G cells◦Histamine H2 receptors

Duodenum Jejunum Ileum Peyer’s patches Peristalsis Ampulla of Vater

http://www.youtube.com/watch?v=xu5jDCX2cHM

Digestive secretions: 3 sources◦Liver Bile

◦Pancreas◦Duodenum Secretin

◦Villi vs. Microvilla◦Structure:◦Function:

◦Villi:◦Capillary network◦Lacteal (lymph

capillary)

◦Hepatocytes◦ Digestive function:

Bile production◦Liver lobules◦Hepatic duct ◦Cystic duct ◦Common bile duct◦Portal vein ◦Hepatic vein◦http://

www.youtube.com/watch?v=tat0QYxlCbo

Bile◦Made by:◦Stored:◦Function:◦Composition:

Produces & excretes bile Glucose/Carbohydrate

metabolism Amino acid metabolism

◦ deanimation Lipid metabolism Synthesis of plasma proteins Bilirubin formation Phagocytosis (Kupffer cells) Storage Detoxification

◦ ETOH & meds◦ Ammonia

2 functions:◦ 1.◦ 2.

When needed, contracts to propel bile to the duodenum

◦ Exocrine◦ Produces

pancreatic juice made of: ◦ 1. Bicarbonate

Function: ◦ 2. Digestive

enzymes◦ Pancreatic duct◦ Common bile duct

Digestive enzymes:◦Protease (i.e.Trypsin)◦Amylase◦Lipase

◦Functions:◦Structure:

◦Ileocecal valve◦Cecum◦Appendix

◦Purpose: ◦Ascending, Transverse,

Descending◦Sigmoid◦Rectum, Anal canal, Anus

◦Normal Flora◦Haustra◦Goblet cells

◦Anal canal◦Anus◦Internal anal

sphincter: ________muscle Relaxes as part of

the defecation reflex

◦External anal sphincter: _________muscle _________ control

Sense of taste Saliva Reduced secretions LES loss of muscle tone Sluggish peristalsis Gallstones, cholecystitis

TEMPERATURE & METABOLISM

Normal range - 96.5-99.5 f Average = 98.6 f Fluctuates 1 to 2 f in 24 hour period Lowest temp during sleep The very young and the very old

Thyroxine Epinephrine Active organ Food intake Fever

Skin

Others: ◦Respiratory tract◦Urinary tract◦Digestive tract

Radiation Conduction Convection Vasoconstriction Vasodilation Sweating

Hypothalamus Mechanisms to increase heat loss Mechanisms to conserve heat

Temperature above 99.5 f

Hypothalamus

Pyrogens

Purposes of fever: 1. 2.

Sum of all chemical reactions

Anabolism

Catabolism

Cell respiration

C6H12O6 + O2 => CO2 + H2O + ATP + heat

GLUCOSE BREAKDOWN: 3 STAGES

◦1. Glycolysis

◦2. Krebs citric acid cycle

◦3. Cytochrome (electron) transport system

Location: Input : glucose & ATP “investment”

◦No O2 needed yet◦Changes (1) glucose to (2) pyruvic acid

Output: pyruvic acid, ATP, high energy electrons & H+ (carried by NADH), heat

If NO O2:◦ pyruvic acid is

converted to lactic acid

If O2:◦ pyruvic acid

continues to the next stage, Krebs cycle

Location: Input: pyruvic acid &

oxygen◦ Others: ◦ Converts each pyruvic

acid molecule into 3 carbon dioxide molecules (one carbon each)

Output: CO2, ATP, high energy electrons & H + (carried by NADH & FAD)

Location: Input: O2, electrons & H+

◦Also need: ◦Transfers the energy that was released in the

form of high energy electrons to ATP. Output: ATP, H20 Most of the ATP comes from this stage

Proteins: made of AMINO ACIDS◦ Extra amino acids DEAMINATED by liver, then

converted into pyruvic acid, acetyl CoA, or ketones◦ Goes directly into Kreb’s cycle

Fats: made of GLYCEROL & FATTY ACIDS◦ Can also be broken down by liver into pyruvic acid,

acetyl CoA, or ketones◦ Goes directly into Kreb’s cycle

KETONES & KETOSIS

calorie: Kilocalorie (Calorie with a capital C)

1 gram FAT = 9 KILOCALORIES 1 gram CARBOHYDRATES = 4

KILOCALORIES 1 gram PROTEIN = 4 KILOCALORIES

GLUCOSE◦ Used to build pentose sugars (DNA & RNA)◦ Extra: Energy stores: Glycogen

PROTEINS: AMINO ACIDS◦Used to build amino acids not obtained in

diet by liver◦Used by tissues to build proteins Hormones Antibodies Collagen Myosin & actin Clotting factors Many more!

FATS: FATTY ACIDS & GLYCEROL◦Used to make phospholipids cell membranes

◦Used to make cholesterol: Cell membranes Steroids (ie. Cortisol,

estrogen) Bile salts Extra: stored as fat in

adipose tissue

Amount of heat production◦Contraction of muscles◦Contraction of heart muscle◦Breakdown of cellular components

The energy required for merely living

Energy at rest

Exercise Age Body configuration of adults

Sex hormones Sympathetic stimulation Decreased food intake Climate

Metabolic rate decreases

Sensitivity to external temp changes