Digestive system Flashcards
overall Function
Mechanically and chemically breakdown food and liquids into smaller particles that can be absorbed
4 functions
Ingestion: into the mouth and oral cavity
digestion: mechanical (physical), chemical (enzyme)
Absorption: Nurtients absorbed into blood and lymph
Elimination: Waste excretion through anus
mastication
chewing / crushing
layers of the GI tract and stomach
Mucosa
Submucous
muscularis
serosa
Upper GI Tract
oral cavity pharynx esophagus stomach initial part of small intestine
lower gastrointestinal tract
small intestine (ileum and jejunum) large intestine Accessory digestive organs - liver - gallbladder -pancreas
Oral cavity and salivary glands
salivary gland secretions mic with ingested food to form a bolus
chemical and mechanical digestion begins
pharynx and esophagus
connect the oral cavity to the stomach
swallowing
- voluntary phase
- pharyngeal phase
- esophageal phase
stomach
surface mucous cells and muscous neck cells
- secretes acidic fluid containing mucin
[muscin: protects stomach lining]
parietal cell
- secretes intrinsic factor and hydrochloric acid
[IF: absorbs vitamin B12, HA creates pepsin]
chief cell
- secretes pepsinogen and gastric liapase
[pepsinogen turns into enzyme pepsin when mixed with hydrochloric acid]
G cells:
- release gastrin (a hormone that stimulates stomach motility (mix and moving) and release of secretions).
regulation of digestive processes
Cephalic phase
Gastric phase
Intestinal phase
- CCK and secretin release
small intestine function
- mixing chyme with accessory gland secretion
- exposing the chyme to different regions of brush border
- moving small intestine contents toward large intestines
large intestines
- watery chime moves in
- LI absorbs water and electrolytes from chyme (leftover forms feces).
- bacteria flora break down complex carbs, protein and lipids.
large intestines
- watery chime moves in
- LI absorbs water and electrolytes from chyme (leftover forms feces).
- bacteria flora break down complex carbs, protein and lipids.
liver
produce bile to facilitate mechanical digestion of lipids
gallbladder
stores and concentrates bile produced by the liver
pancreas
produce pancreatic juice
- alkaline cocktail of numerous digestive enzymes.
carbohydrates
starch
glycogen (amylase)
- maltose
- sucrose
- lactose
protein
The stomach denatures protein by protease.
peptides and amino acids are absorbed.
fats
triglycerides (ingested)
broken down and emulsified by bile in the stomach and lipase enzyme.
fatty acids and glycerol absorbed
catabolic
decomposition
- breakdown of molecules/nutrients into smaller particles
- used by body for fuels and to heat body temperature
Anabolism
systhesis
- using simple molecules/ nutrients to form complex one
- form new cells and tissues, store energy.
Metabolism
Chemical reactions
- breaking bonds between nutrients, molecules, and reorganization of molecular structure.
- classified as anabolic or catabolic
glycolysis
breakdown of glucose within cells cytosol
Glycogenesis
Anabolic
- long chains of glucose called glycogen are formed and stored for use
Glycogenolysis
catabolic
- Breakdown of glycogen to release stored glucose
fat-soluble
Dissolved in fat
absorbed by the gastrointestinal tract and enters the lymphatic system.
ADEK (Vitamin A, D, E AND K)
water-soluble
Dissolved in water
Easily absorbed in the blood from the digestive tract
[vitamin B 1, 2, 3, 5, 6, 7, 9, 12 and C]
calcium
Bone strength
muscle strength
Phosphorus
Energy
Metabolism
Potassium
Electrolyte and fluid balance
Zinc
Hair and nail stength
Skin
sodium
water exctretion
fluid balance
