Exam 3. Respiration, Digestion, and Metabolism
College: Second year
5 Functions of the Digestive System
1. Ingest Food
2. Prepulsion (peristalsis)
3. Digest (breakdown)
4. Absorption
5. Defacation
2 Digestive Processes
1. Mechanical
2. Chemical
Specific proteins that are temp and pH sensitive
Enzymes
Enzyme to break down Sucrose
Sucrase
Enzyme to break down Lactose
Lactase
3 Parts of the Small Intestine
-Duodenum
-Jejunum
-Ileum
6 Parts of Large Intestine
-cecum
-appendix
-ascending colon
-transverse colon
-descending colon
-sigmoid colon
Sphincter located between stomach and small intestine:
pyloric shincter
Sphincter located between rectum and anal canal:
Internal anal sphincter
Only sphincter with voluntary control:
external anal sphincter
Organ that produces bile to send thru the hepatic ducts:
Liver
Hepato
Liver
Cysto
Gallbladder
Organ attached to underside of liver that stores bile:
Gallbladder
Secretes many enzymes and bicarbonate (HCO3-)
Pancreas
Pathway for Bile:
Hepatic Duct & Cystic Duct > common bile duct > Hepatopancreatic Sphincter > Duodenum
98% water, antibodies, lysozyme, mucus
Saliva
functions to cleanse the moth, moisten food, help with chemical breakdown:
Saliva
3 Salivary Glands:
1. Parotid
2. Sublingual
3. Submandibular
Organ that absorbs and digests nutrients
Small intestine
4 Layers of S.I. Tract
1. Mucosa
2. Submucosa
3. Muscularis externa
4. Serosa
pH of the Mouth
6.8
pH of the Stomach
1.8
pH of the SI
5.4
What do these have in common- H2O, minerals, vitamins, glucose, alcohol
Substances which do NOT require digestion
No digestion or absorption
Esophagus
Upper 1/2 of Esophagus is made up of what type of muscle?
Skeletal Muscle - Voluntary
Lower 1/2 of Esophagus is made up of what type of muscle?
Smooth Muscle- Involuntary
Reverse Peristalsis
To Vomit
Functions of the Stomach:
1. aid in digestion
2. Acid secretion
3. Stores food
4. Produces Intrinsic Factor
Protein needed to absorb Vitamin B12 and needed for RBC Synthesis to maintain neurons:
Intrinsic Factor
Feeling of fullness:
Satiety
3 Muscle Layers of the Stomach:
1. Circular
2. Longitudinal
3. Oblique
Lining of Stomach:
Mucosa and Submucosa
Pepsin and HCl can erode mucosa in stomach leading to:
Ulcers
4 things needed for enzyme reactions to work:
1. Enzyme is specific to substrate
2. Correct (body) temp
3. Mixing
4. correct pH
How long does food stay in the stomach
4-6 hours
What organ has a massive surface area?
Small Intestine
Key structures of SI
Plicae circularis, villi, microvilli
2 Absorption Routes
Water soluble and fat soluble
4 Lobes of the Liver
Right, Left, Caudate, Quadrate
7 Functions of Liver
1. Detox
2. Stores fat soluble vitamins
3. Store Iron
4. Process nutrients
5. Lipogenesis
6. Protein synthesis
7. produces bile
When bile becomes too concentrated and crystalized
gallstones
Inflammation of the liver tissue:
Hepatitis
Chronic inflammation of liver due to viral infection or alcoholism-liver cells die, scar tissue forms
cirrhosis
Liver enlarges:
Fibrosis
3 Movements of Colon (LI)
1. Haustral churning
2. Peristalsis
3. Mass Movements
Reside in colon to breakdown fiber which then creates gases:
Bacteria flora
Functions of the colon:
1. water absoption
2. absorb vitamins
3. form and eliminate feces
out-pocketing of weakened sidewalls (LI)
diverticulitis
Most likely for Colon Cancer
Sigmoid and Rectum