Digestive system #9

Question 1

Digestive sys functions

Answer 1

provide body with essential nutrients
Maintain adequate levels of all essential nutrients in body

Question 2

Digestive process

Answer 2

Ingestion
-Food into mouth, chewing and swallowing
Secretion
-acid, water, enzyme secreted into lumen of GI
mixing&proportion
-ability of GI to mix and proper food along its length
Digestion
-Mechanical and chemical process of breaking down food into smaller molecules
Absorption
-Digested food transported through walls of small intestine and into circulatory system
Elimination
-removal of waste products and undigested food

Question 3

GI tract components and its functions

Answer 3

Mouth
saliva- contain salivary amylase that breaks down starch into mlatose,lubricates food
tongue- rolls food into bolus
teeth mastifcation,food is cut and ground
Pharynx
lined with cavity
tongue pressed against rood of mouth to push bolus intopharynx then eoseophagus
epiglottis prevent bolus from entering trachea
eseophagus
lined with mucosal membrane
peristaltic contraction to push bolus into stomach
doesnt secrete enzyme

cardial sphincter
muscular ring
relaxes when peristaltic contraction appraches to allow food to enter stomach
valve to prevnt backflow of stomach content

stomach
physical breakdown of food
chemical digestion occur in pylorus
mixture of food and gastric juices(chyme)
gastric juices contain hcl-kill most microbes
pepsinogen converted to pepsin to break down protein into polypeptide
mixes and churns food (peristaltic contraction)

pancreas (accessory organ)
secretes pancreatic juices
sodium bicarbonate:
inactivate pepsin
increase ph for intestinal enzymes to act on
buffer acidic gastric juices in chyme

pancreatic enzyme
trypsin,aminopeptidase-digetsion of protein
amylase-digestion of carbs
lipase-digestion lipids

accessory organ-liver
produces bile(breaks down fats into smaller molecules,increasesSA(emulsification)
detoxification
converts alchohol into aldehyde
ammonia into urea
maintain blood glucose level
glucagon and insulin
produces waste products
bilirubin from haaemoglobin breakdown
SI
pylroic sphincter that controls the amount of food entering SI
site of final digestion of macromolecules
villi,microvilli increases SA
duodenum and jejunum_ absorption of lipids,amino acids
iluem-absorption of water,bile salts

Large intestine
absorption of water,electrolytes
surface absorption no villi,
doesnt produce enzyme
contain large amount of bacteria
anus involuntarily controlled