digestive system part 2 Flashcards
how is most of the fat in the body stored
triacylglycerides
what are chylomicrons?
longer fatty acid chains packaged into smooth ER and Golgi with a protein coat
what makes up the gastrointestinal tract?
mouth/pharynx/esophagus
stomach
upper/small intestine - digestion and absorption
lower/large intestine - absorption of water
anus - release of indigestible material
what are the three compartments of small intestine
duodenum, jejunum, ileum
what are the four types of teeth
incisors canines - piercing and tearing premolars molars - breaking up and grinding
role of salivary glands
- lubricate food to go smoothly down GI tract
- secret enzymes - salivary amylase
- anti-microbial
nervous system control on salivation
parasympathetic - stimulate salivation
sympathetic - inhibit salivation
what layer is the gut derived from
endoderm
what are the three regions of gut
foregut
midgut
hind gut
how is nutrient uptake improved?
increasing surface area in
- increasing gut length
- increasing surface undulations
ex. . circular folds, villi, microvilli
what are ruminants
herbivores that have 4 compartments of stomach in order to digest plant material
ex. cattle sheep goats deer and giraffes
what are the four compartments of ruminants stomachs
reticulum
rumen
omasum
abomasum
what are the types of epithelial cells in the stomach
tight junctions mucous neck cells parietal cells chief cells enteroendocrine cells
tight junctions
prevent leakage across epithelium
mucous neck cells
stomach: secrete mucus
gel like substance protects stomach
parietal cells
stomach: secrete hydrochloric acid
chief cells
stomach: secrete protease pepsin in the form of pepsinogen
enteroendocrine cells
stomach and intestine: secrete hormones into the blood
ex. gastrin
what are the four main layers of the intestine
mucosa
submucosa - blood/lymphatic vessels and nerves
circular smooth muscle
longitudinal smooth muscle
enterocytes
intestine: absorptive cells with microvilli
goblet cells
intestine: secrete mucus
panteth cells
intestine: secrete antimicrobial molecules
crypt of lieberkuhn
intestine: secretes sucrase, maltase, lactase and peptidase
bile characteristics
solution of digestive chemicals and liver waste product
produced in liver, stored in gallbladder
emulsifies fats and uptakes lipids
proteases function
break down proteins
secreted as inactive proenzymes which are activated in the intestine
ex. trypsinogen, chymotrypsinogen, procarboxypeptidase
amylase function
breaks down glycogen and starch
lipases function
break down triglycerides
nucleases function
break down nucleic acids
what cells in the pancreas secrete enzymes
acinar cells
how does food move along the GI tract
contractions of smooth muscle controlled by nerves/hormones
what is the optimal speed for gut motility
fast enough to minimize indigestible material in the GI tract
slow enough to allow time for digestion and absorption
what are the smooth muscle layers in the gut
longitudinal - controls length and peristalsis
circular- controls diameter and segmentation
how is the smooth muscle of the gut controlled
myogenic and neurogenic
what is myenteric plexus
nerve network located in between muscles of the gut
receives signals from para/sympathetic nervous systems
