Fundamentals of Biology: Lecture Outlines - Chapter 41- Digestion and Nutrition
TASKS:
1. Mechanical
2. Secretion
3. Digestion
4. Absorption
5. Elimination
Anatomy
Digestive tract
Accessory Organs:
Salivary glands, liver, gall bladder, pancreas
MOUTH
Saliva = salivary amylase, bicarbonate, mucins, water
Bolus =
Swallowing
- contract tongue
- larynx rises
- epiglottis
ESOPHAGUS
- long, muscular tube
- ends at gastroesophageal sphincter
STOMACH
- muscular
1. Mixes and stores
2. Secretions dissolve
3. Controls passage
Stomach lining = mucosa
Chyme =
Heartburn -
HCl acid
- exposes
- converts
Peptic ulcers - erosion of stomach wall
- often caused by bacterial infection
SMALL INTESTINE
- lined with simple columnar epithelium
3 regions:
1. Duodenum
- ducts from pancreas, liver, gall bladder
- Pancreas - secretes sodium bicarbonate
- amylase
- trypsin
- lipase
- nucleases
- Liver
- bile salts
- bilirubin
- cholesterol
- waste
2. Jejunum
3. Ileum
Villus = fingerlike projection of the mucosa
- absorptive cells covered by microvilli
- other cells for mucus
- each villus supplied with blood and lymph
Absorption
- passage of nutrients, water, salts and vitamins
- aided by segmentation
Micelle formation
- bile salts combined with products of fat digestion
- triglycerides + proteins = chylomicrons
LARGE INTESTINE (colon)
- concentrates + stores feces
Feces =
- begins at cecum
- appendix
- ascending colon
- transverse colon
- descending colon
- sigmoid colon
- rectum
Colon Functioning:
- cells in colon actively transport sodium
- water concentration rises
- water follows sodium
- cells also secrete
- mucus
- bicarbonate buffers
HUMAN NUTRITION
- food pyramids
- 55-60% carbohydrates,
- Main carbohydrates in diet
- Lipids
- Essential fatty acids
- Proteins
- 20 types of amino acids
- Essential amino acids
- animal proteins = complete
- plant proteins = incomplete
Vitamins - organic
Minerals - inorganic
Review
Review questions 1-4
Self quiz 1-6, 8-10
Critical Thinking #1