Stages of digestion
Ingestion, Propulsion, Mechanical Digestion,Chemical Digestion, Absorption, Defecation
Ingestion
Selective intake of food
Propulsion
Swallowing and peristalsis
Mechanical Digestion
Physical Breakdown
Chemical Digestion
Hydrolysis reactions by enzymes
Absorption
Uptake of nutrient molecules in epithelial cell and into blood and lymph
Defecation
Elimination of feces
What is the difference between mechanical and chemical digestion?
Mechanical-chewing, churning and segmentation(physical breakdown)
ex: Grinding teeth, churning action of stomach/small intestines
Chemical-enzymes breaks down complex food molecules to basic building blocks
ex :polysaccharides into mono, protein into amino acids, fats into monoglycerides and fatty acids, nucleic acids into nuclotides
What components of the body make up the digestive tract?
mouth, pharynx, esophagus, stomach, large and small intestines
What components make up the accessory organs?
teeth, tongue, salivary glands, liver, gallbladder, pancreas
Explain the reflexes involved with defecation?
Intrinsic Defecation Reflex-involuntary
- Works entirely within the myenteric plexus
- Stretch signals travel thru plexus to muscularis, causing it to contract and internal sphincter to relax
Parasympathetic Defecation Reflex-Involuntary
- Strecthing of rectum sends sensory signal to spinal cord
- Pelvic nerves return signal, intensifying peristalsis and relaxing internal and sphincter
- Defecation occurs if external and sphincter is voluntarily relaxed
Describe the basic steps to carbohydrate
- Salivary and pancreatic amylase digests polysacharides into disacharides
- disaccharides brokendown into monosaccharides by maltase, sucrae or lactase
- absorbed by blood capillaries
Basic steps to protein
- Pepsin begins protein digestion
- Trypsin and Chymotrypsin break protein an polypeptides into small peptides
- Peptidase breaks small peptides into amino acids
- Amino acids absorbed by blood capillaries
Basic steps to lipid
Emulsified-fat broken
The three segments of the small intestine, and describe what role they play in digestion
Duoenum-recieves pancreatic ducts
Jejunum-Digestion and absorption
Ileum-Lymphatic nodules
Describe the flow of blood
Hepatic portal vein-sinosoids-central vein-R&L hepatic vein-IVC
Describe the bile through the liver
Bile ductules-R&L hepatic ducts-common hepatic duct-cystic duct-Bile duct-duodenum
How many teeth we have as children
20
How many teeth we have as adults
32
Dental formula for adults
21234
Describe the stuctures of the mouth including the terms
Labia(cheecks/Lips)retains food and push it between teeth for chewing
Vestibule-space between cheeks or lips and teeth
Labial Frenulum-median fold that attaches each lip to gum between anterior incisors
Hard and soft palate-separates oral cavity. Hard anterior, Soft posterior
Uvula-closes off nasopharynx during swallowing
Tongue- manipulates food between teeth while avoid being bitten
Cheeks- retains food
What is the different types of lingual papille on the tongue?What is the purpose
Sites of taste buds
Vallate
Fungiform
Filiform
what purpose do incisors
cutting
canine
shred
