Digestive System Physiology Flashcards
what are the building blocks of food
lipids, carbohydrates, proteins, nucleic acids, and high E compounds
what is the Carbon, Hydrogen, Oxygen ratio found in all carbohydrates?
1C:2H:1O
what do carbohydrates include?
polysaccharides, which contain disaccharides, which are composed of two monosaccharides
what do lipids include?
triglycerides, which are composed of fatty acids and glycerol
what are proteins composed of?
peptides, which are composed of amino acids
how many types of amino acids are there, and how many proteins can they form?
20 different types of amino acids, a limitless possibility of connections to form proteins
what do nucleic acids include?
either RNA or DNA, which is composed of nucleotides
what do high energy compounds include?
ATP, which is composed of nucleotides and phosphate groups
what is a primary protein structure?
an amino acid sequence
what is a secondary protein structure?
hydrogen bounding to peptide ‘back bone’, causing amino acids to ‘fold’ into pleated sheet and alpha helix
what is tertiary protein structure?
3-D folding pattern of a protein causing by side chain interactions
what are quaternary protein structures?
proteins consisting of more than one amino acid chain
what are the 3 salivary glands, and their relative positioning around the mouth?
parotid glands: near the ear
sublingual glands: directly under the tongue
submandibular glands: near the mandibular angle
what are the types of digestion that occur?
mechanical digestion and chemical digestion
name the 3 muscle layer of the stomach and their function
longitudinal muscle (superficial most layer): pulls the bottom of the stomach up
circular muscle: pulls the stomach side to side
oblique muscle (deepest muscle layer): pulls the stomach diagonally
name the alimentary canal structures, in order
mouth/oral cavity, pharynx, esophagus, cardiac sphincter, stomach, pyloric sphincter, duodenum, jejunum, ileum, ileocecal valve, cecum, ascending colon, transverse colon, descending colon, sigmoid colon, rectum, anal canal, anus
what protects your body from your stomach juices
thick layer of mucus on the stomach walls (a majority of gastric glands produce this mucus)
what are the 5 nucleotides?
adenine (A), cytosine (C), guanine (G), thymine (T), uracil (U)
at what temperature do human proteins begin to denature, and at what temperature will a person be declared clinically dead at
proteins denature: 40.5C (105F)
clinically dead: 42.2C (108F)
what is the pH of the stomach?
pH of 2
what are the 5 cell types in the stomach?
goblet cells, parietal cells, chief cells, D cells, and G cells
what do goblet cells secrete in the stomach?
mucus (to protect the stomach lining)
what do parietal cells secrete in the stomach?
gastric acid (HCl)
what do chief cells secrete in the stomach?
pepsinogen
what do D cells secrete in the stomach?
somatostatin (inhibits acid secretion)
what do G cells secrete in the stomach?
gastrin (stimulates acid secretions)
in what environment can cancer live in?
cancer can ONLY live in an acidic environment
how does your body defend against ingesting toxic substances?
spitting out, throwing up, and diarrhea
what does everything absorbed via digestion pass through?
everything MUST pass through the hepatic portal vein
what is a negative feedback loop?
a physiological process that occurs as a means to regulate homeostasis
what is a positive feedback loop?
a physiological process with a definitive end (ex. blood clotting)
what is blood sugar managed by?
by the pancreas and the liver
what is glycogensis?
the formation of glycogen by liver, caused by production of high blood sugar and pancreatic production of insulin
what is glycogenolysis?
the ‘chopping’ off of glycogen into sugars, caused by production of glucagon by the pancreas
how long does it take for all the blood in the body to be replaced?
around 90-120 days
what do dead erythrocytes (red blood cells) break down into?
dead erythrocytes break down into hemoglobin
what does hemoglobin break down into?
hemi and globin
what is hemi turned into?
hemi gets turned into iron and bilirubin
-the iron goes into the bone marrow, which in turn produces more erythrocytes
-the bilirubin turns into bile by the liver before being stored in the gallbladder
what does globin turn into?
globin is recycled into amino acids
what does the liver make as a by-product of digestion?
the liver makes urea, which is the #1 molecule found in urine
why is not using the restroom so dangerous?
uric acid can form in the blood and turn into ammonia (deadly!)
how does your body get rid of urea?
via urination and via sweat
what are the stages of digestion?
ingestion, digestion, absorption, assimilation, and egestion
what is ingestion?
the taking in of food into the body
what is digestion?
the break down of food into smaller, simpler compounds
what is absorption?
the diffusion of food nutrients into the blood
what is assimilation?
the usage of digested materials to make new materials
what is egestion?
the removal of undigested waste from the body
(the removal of fecal matter is defication)
what is peristalsis?
peristalsis is a rhymic, wave-like contraction that happens in the gut wall via the contractor of antagonistic muscles that push food into the body
what does bile do?
bile emulsifies fats, increasing their surface area for digestion
what does a lacteal do?
lacteals absorb fat as fine droplets into the lymphatic system
what are the 7 main functions of the liver?
production of heat, regulation blood sugar concentration, detoxification the body, create bile, storage of iron, syntization of proteins, and deamination of amino acids
what type of tissue is the area between the mouth and esophagus called?
striated epithelial tissue (sheets of flat, shedding tissue)
what type of tissue is the area between the stomach and the large intestine called?
columnar epithelial tissue (boxy, secreting and absorbing cells)
what does the suffix ‘ase’ mean when referring to enzymes
enzymes that are functional
what does the suffix ‘gen’ mean when referring to enzymes
the enzymes must be activated
what are the different parts of the stomach lining?
mucosa, submucosa, muscularis, serosa
what is a function/characteristic of the stomach layer mucosa?
contains gastric pits and glands that secrete mucus
what is a function/characteristic of the stomach layer submucosa?
contains bloodvessels
what is a function/characteristic of the stomach layer muscularis?
contains the muscles of the stomach (oblique, circular, and longitudinal)
what is a function/characteristic of the stomach layer serosa?
a connective tissue layer, visceral peritoneum
what does the stomach typically absorb?
water, monocaccharides, alcohol, and asprin
what is the length of the small intestine, both postmortem and during life?
postmortem: 20 ft
during life: 12 ft
what is the small intestine lining made out of? (elaborate more than just the tissue layer)
composed of columnar epithelial cells that contain a brush border of microvilli
what is a lumen?
the cavity or channel, in the small intestine it contains villi, and the microvilli brush border
what does a villi do?
absorbs water soluble nutrients into the blood stream
what does lacteals do?
absorb fat into the lymphatic system
what does the sphincter of oddi do?
controls flow of fluid from the pancreatic duct and common bile duct
what does the duodenum do?
enzymatic digestion of chyme
what does the jejunum do?
absorption of sugars and amino acid actively transported across mucosal lining
what does the ileum do?
absobtion
what does the pancreas do?
manufactures hormones and digestive enzymes (such as insulin) and regulates blood sugar
what is the downside of pancreaticly produced enzymes?
the insufficient and often slow delivery of products into the duodenum via pancreatic duct
what cell aids in the production of bile ?
Kupffer cells, which eat dead erythrocytes
fun fact: how many layers of cells protect your body from the deadly gastric juices
1 layer of cells
what is the longest part of the small intestine?
the ileum (~12 ft long)
