Download Ch 14 Digestive System

Digestive System
Chapter 14
In your groups…you will come up with
a definition (using YOUR WORDS) and
a colored picture of it happening in the
body. You will be presenting this to the
class. YOU MAY NOT USE BOOKS!!!!
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6.
Ingestion
Physical Digestion
Mechanical Digestion
Propulsion
Chemical Digestion
Absorption
Digestion (at organ and system level)
Ingestion: take in food
Physical digestion: food breakdown
Mechanical: food breakdown; segmentation
Propulsion: movement of food; peristalsis
and swallowing
Chemical digestion: breakdown of food molec. by enzymes
Absorption: transport of food from GI tract to blood or lymph
Defecation: elimination of indigestible substances; feces
Chemical Digestion vs
metabolism
Chemical digestion occurs in system, then cells
use nutrients for metabolism
Anabolism- building up of molecules
Catabolism- breaking down of molecules= hydrolysis
Digestive System
GI Tract
(Alimentary Canal)
Mouth
Pharynx
Esophagus
Stomach
Sm Intestine
Lg Intestine
Anus
Accessory
Organs
Teeth
Tongue
Salivary Glands
Liver
Gall Bladder
Pancreas
Histology of GI tract wall
Layers: Mucosa, submucosa, muscularis, serosa
Lumen: opening/hollow center
Membrane: peritoneum (visceral & parietal)
Peritoneum- Membrane
Visceral peritoneum
Peritoneal cavity
Parietal peritoneum
Nutrition, Chemical Digestion and
Metabolism
Nutritional polymers broken down into
monomers (or building blocks) during
digestion …then metabolized
proteins
carbohydrates
Nucleic acids
lipids
Carbohydrates
monosaccharide
Monosaccharide - glucose,
fructose, galactose
Disaccharides- lactose,
maltose, sucrose
Polysaccharidesstarches, cellulose, fiber,
glycogen
Energy source:
pasta, bread,
cellulose, sugar
polysaccharides
disaccharide
Lipids
Fats, Oils, Waxes, Cholesterol
Insulation,
membranes,
energy
diglyceride
Fatty acids
BAD FOR YOU
Lipids
(builds up in arteries & leads to
heart disease)
Saturated Fats: increase LDL (butter)
 Unsaturated Fats: decrease LDL
(vegetable oils)
 Polyunsaturated Fats: Omega-3 ( nuts,
fish oil, leafy greens)

Proteins
Tissue Maintenance and Growth, enzymes
Amino acids
(building blocks)
dipeptide
polypeptide
Nucleic acids
RNA
DNA
nucleotide
sugar
Digestive organ anatomy
and physiology
Oral Cavity Anatomy
Teeth
Tongue
Cheeks
Lips
Hard and Soft Palates
*Tonsils
*Uvula
Salivary glands- saliva
Salivary Gland Secretion
SALIVA
•Contains enzyme called
salivary amylase
(starch breakdown)
•chemically digests
polysaccharide starches
into disaccharides
•Mumps (disorder) – swelling, pain of salivary glands
Oral cavity physiology
1. Ingestion
2.& 3. Physical digestion
•Mechanicalmastication by teeth,
mashing by tongue
•Propulsionswallowing by tongue
4. Chemical digestionsaliva contains enzymes
(amylase)
lips
Pharynx anatomy and physiology
1. Physical
•Propulsionswallowing,
peristalsis
Esophagus anatomy
and physiology
1. Physical
• Propulsionperistalsis
•Heartburn (disorder)
Stomach anatomy
cardia
Peptic ulcers
H. pylori
vomiting
Microscopic stomach anatomy
rugae
Stomach Secretion
•Gastric juice
•Contains HCl, pepsin(ogens), mucus, intrinsic
factor, gastrin, rennin for milk proteins
•Pepsin(ogens) chemically digest protein
subunits called polypeptides into dipeptides
•Food liquified into chyme
Stomach physiology
1. & 2. Physical
•Mechanical-churning,
mixing
•Propulsion- peristalsis
3. Chemical-gastric juice
contains pepsin(ogen)
enzymes
4. Absorption of drugs,
alcohol, and a little H2O
and electrolytes- hepatic
portal circulation to liver
Digestive System Lab
Liver anatomy
Disorders: Jaundice (bilrubin), cirrhosis (scar) , hepatitis (swelling & inflammation)
Liver anatomy
Liver secretion
•Produces bile which
empties into duodenum of
sm. intestine
•contains H2O, bile salts,
pigments, cholesterol,
electrolytes, phospholipids
•Bile salts emulsify fats into smaller fat droplets,
but no enzymes
Liver physiology
1. Chemical digestion??
Bile salts (empties
into duodenum)
but contains no enzymes
2. Other functions:
filters toxins,
phagocytizes old
RBC’s, transports lipids
to lymphatic system,
anabolism and stores
excess nutrients after
anabolism
Gall bladder anatomy and physiology
1. Stores and releases excess bile from liver into
duodenum
Disorder: gallstones
Pancreas anatomy and physiology
1. Chemical digestion- secretes pancreatic juice into
duodenum, contains enzymes, (see next slide)
Disorder: diabetes
Pancreas Secretion
•Pancreatic juice empties into duodenum of small
intestine and neutralizes chyme
•Contains most enzymes of all organs:
1. pancreatic lipase - digest lipids
2. pancreatic amylase - digest carbs
3. nuclease - digest nucleic acids into nucleotides
4. trypsin, chymotrypsin, carboxypeptidase
- digest proteins
Small Intestine anatomy
Disorder: Lactose intolerance
Small Intestine anatomy
Containing
lacteals
and
microvilli
VILLI
Small Intestine Secretion
•Intestinal juice with brush border enzymes
•Contains enzymes for complete digestion into nutrients:
1. Intestinal lipase - digest lipids
•
2. Nuclease - digest nucleic acids into nucleotides
3. Maltase, sucrase, lactase -digest carbs
4. Peptidases - digest proteins
Small Intestine physiology
1. & 2. Physical
•Mechanicalsegmentation
•Propulsionperistalsis,
segmentation
3. Chemical- intestinal
juice contains enzymes
(see previous slide)
4. Absorption of electrolytes & NUTRIENTS!!!!- most
absorption in entire system and only place to absorb
nutrients!!!
Large Intestine anatomy
Disorders: Flatulence, hemorrhoids, constipation, diarrhea
Large Intestine Secretion
•Mucus, but no enzymes
•Bacteria (E.coli) digest??? (no enzymes)
remaining carbohydrates and proteins into
odoriferous gases, released during flatulence
•Bacteria produce vitamin K and B
1 Physical
Large Intestine
physiology
•Propulsionperistalsis and
defecation reflex
2. Chemical??-by
bacteria, (see previous slide)
3. Absorption of
H2O!!!! electrolyteshepatic portal
circulation to liver
4. Defecation
Overview of physiology
(organs involved in each function)
Ingestion-oral cavity
Physical digestion
mechanical- oral cavity, stomach, sm intestine
propulsion-oral cavity, pharynx, esophagus,
stomach, sm and lg intestine
Chemical digestion by enzymes-salivary glands in oral
cavity, stomach, liver??, gall bladder??, pancreas, sm
intestine, lg intestine??
Absorption into blood- stomach, sm and lg intestine
Defecation- lg intestine
Overview of physiologychemical digestion
Carbohydrates- salivary glands in oral cavity,
pancreas, sm intestine, lg intestine??
Lipids- liver??, gall bladder??, pancreas, sm intestine
Proteins- stomach, pancreas, sm intestine, lg intestine??
Nucleic acids- pancreas, sm intestine