digestive system Flashcards
brachydont teeth
low-crowned teeth, root imbedded in jaw bone, enamel covers entire tooth
hypsodont teeth
teeth made for more wear and tear, high crowned teeth
grow continually
mono gastric digestion
performed by animals own digestive enzymes until partially digested enters intestines L intestine has many microorganisms that digest through fermentation
ruminants
complex stomachs
microorganisms have 1st opportunity to digest feed. large intestine as well
4 major functions of digestive system
- ingestion, mastication, digestion, elimination
major organs od GIT (6)
mouth, pharynx, esophagus, stomach, small and large intsetine
big ol tube
accessory organs of GIT
teeth, tongue, salivary glands, liver, pancreas, gall bladder
lumen
long tube from mouth to anus, opening in middle of intestinal tract is lumen, site of partially digested feed
mucosa
next to lumen, innermost layer
made of epithelial tissue, involved in most digestive absoprtive and secretory processes.
goblet cells to secrete mucus and villi for nutrient absorption
submucosse
under mucosa, connective tissue, contains blood and lymph vessels and nerves
serosa
outermost layer, loose connective tissue, reduces friction from muscle movements
prehension
ingestion of food
can involve teeth, tongue, lips, and movement of head and jaws
incisors for cutting grass or capture prey
what bone are the lower tech in?
mandible
what bone are upper canines, molars and premolars in>
maxilla/maxillary bone
upper incisor location
premaxilla/incisive bone
teeth function
particle size reduction
food gathering
protective function
mastication
order of the teeth from upper front to lower front
incisors canine premolars molars lower molars premolars canine incisors
pharynx/throat
common passage for food and air
connects nasal and oral cavities w trachea and esophagus respectively
mucus
produced in mouth, nose, sinuses, throat, lungs, and throughout the gastrointestinal tract
mucus function
lubricant
contains antibodies, enzymes, proteins to attack microbes
protects mucosa in GIT from enzymes and acids
esophagus
collapsable muscular tube that extends from pharynx to stomach
goes down w peristalsis
cardiac sphincter at gastric end to prevent back flow of acidic contents from the stomach in the case of non-ruminants
functions of simple stomach
storage and mechanical breakdown of ingested food. secretes digestive juices
production of intrinsic factor to facilitate bit. b12 absorption
cardia
part of the simple stomach - entrance to the stomach at junction of esophagus and stomach
named after proximity to heart
mucus glands to secrete alkaline mucus against damage from gastric acids
fundus
distensible sac - basically top of stomach
prominent ruge - allows to expand and hold a meal
increase surface area for absorption
rugae
transient folds in mucosa, allows stomach to expand
mucus produced from it to protect cells from acid
body/corpus
mixing tank, size dependent on extent of filling. largest section of the stomach
pyloric
muscular sphincter present to regulate flow fo chyme into small intestine and prevent duodenal contents into stomach
esophageal mucosa
by cardia, secretes mucu jk doesnt do that
where is mucus secreted in non-ruminants
esophageal, cardiac gland region, fund gland region
pyloric gland region
which stomach is most similar to simple stomach in ruminants
ABOMASUM - last stomach
reticular groove
mucosa form a muscular fold or groove/tube that connects cardia of esophagus to omasum so milk will bypass underdeveloped reticulum/rumen so it won’t sour
reticulum
honeycomb structure, can get hardware disease, pumps liquid to rumen and regulates outflow of digests to rumen and omasum
reticulorumen
fermentation vat where ingested feed is fermented by microorganisms, site of chemical digestion
rumen is like a rug
rumen also mechanically/physically digests bc of mixing actions
4 Rs of rumination
regurgitation, remasticating, reensalivation and reswallowing. done to reduce particle size
forage particle size
smaller forage is easier to eat more, also influences rumen health, greater particle size means more chewing
lactating cows get larger particle size to increase rumination mixing for saliva secretion, increases milk fat
small intestinw
most of the digestion
duodenum, jejenum, ileum
pancreas and hepatic bile ent to provide secretions to aid digestive process
jejunum is longest section and site of most digestion and absorption
ileum is extensive mucus secretion
large intestine
includes cecum, colon, rectum, and anus.
wide diameter, species differences on the extent of fermentation
large intestine function
microbial fermentation and vitamin synthesis in cecum and colon
electrolyte and water absorption
fecal formation
expulsion of shit
species differences for LI
horses have larger large intestine to maximize fermentation. large capacity
salivary gland
used for saliva production
digestive function of salivary gland
dissolves food to aid taste and start digestion amylase for starch digestion mucus forms bolus buffers acidic foods, protective thermoregulation
pancreas
runs by descending duodenum endocrine function (makes hormones like insulin) exocrine function (digestive enzymes, sodium bicarb)
liver
largest gland in the body , first organ to process blood from GIT, metabolic powerhouse of the body
removal of waste products
synthesis of bile salts
gall bladder
in all domestic animals except for horses
concentrate and stores bile for fat digestion
bile enters duodenum
