function of upper esophageal sphincter
open/close entrance to esophagus
function of cardiac sphincter
open/close entrance between esophagus and stomach
function of pyloric sphincter
open/close at bottom of the stomach to let food into small intestines. allows a few mls at a time so SI can neutralize the stomach acid with bicarbonate to decrease injury to SI and because SI enzymes needs neutral pH
function of ileocecal sphincter
located between end of ileum and cecum. prevents backflow of colon contents into SI
function of anal sphincter
control of defacation
what precursor molecule does pepsin come from and what type of cell makes this precursor?
pepsin comes from pepsinogen and is secreted by chief cells. exocrine signaling
what parameter limits pepsins function?
pepsin is pH sensitive. Activated at low pH, high pH inactive.
which hormone is secreted by thoughts of food and food in the stomach?
what is gastrin secreted from?
the pyloric region of the stomach and duodenum
acid and protease production in the stomach is stimulated by what hormone?
which hormone is secreted in response to acid chyme and protein digested in the duodenum?
where is secretin secreted from?
duodenum and jejunum
what does secretin stimulate the pancreas to produce and secrete?
fats and protein in duodenum stimulates this hormone
where is CCK secreted from?
duodenum and jejunum
what hormone stimulates the flow of bile and pancreatic fluids into the duodenum?
what receptors attract us to carbs and salt?
salt and sweet
what receptors repel us from toxins?
receptors that repel us from acidic/fermented food?
receptors attract us to protein?
umami receptors detect which AA? and name the stable form of the AA.
glutamate and stable form is MSG
how is surface area increased in the small intestines?
microvilli and villi increase surface area for absorption by 600x
How much energy do carbs supply?
How much energy do proteins supply?
How much energy does alcohol supply?
How much energy do fats supply?
which molecule links TCA cycle with gluconeogenesis?
Fiber is made of _____ linkages that point _______and are not able to be digested by humans
starch and glycogen have ________ linkages that point _________ and are able to be digested
In the disease PKU, the enzyme ___________________________ is missing or reduced. This decreases the amount of the amino acid ____________________ causing it to become a(n) ___________________ amino acid. It also causes a build-up of the amino acid __________________________which results in the removal of its ________ in a _________________________________ reaction converting it into _______________. If left untreated it can cause mental retardation because accumulation of __________________ blocks other amino acids from crossing the _________________________.
phenylalanine hydroxylase. tyrosine. essential. phenylalanine. NH2. transamination. Phenylpyruvate. phenylalanine. blood brain barrier
what food can PKU people not eat?
monosaccharides of maltose
2 glucose molecules
monosaccharides of lactose
glucose and galactose
monosaccharides of sucrose
fructose and glucose
monosaccharides of raffinose
glucose, fructose, and galactose
What are the benefits of carbohydrates?
- Support glycogen reserves in muscle
- Support glycogen reserves in liver (needed from brain metabolism)
- Protects against ketosis and protein loss
- Provides fiber
benefits of soluble fiber
- Binds glucose so slows glucose absorption & reduces risk of diabetes
- Binds cholesterol and bile which increases their excretion & reduces risk of cardiovascular disease
- Reduces appetite & reduces risk of obesity
- Feeds microbiota of colon & supports GI track and immune system and suppresses inflammation
- Lowers risk of breast cancer
- Decreases Asthma
- Decreases mortality rates
- Helps prevent Crohn’s disease
how are calcium and fiber related?
Cell injury caused by fiber leads to Ca++ influx. The Ca++ causes the mucus filled vesicles inside the cell to come to the surface and fuse together to repair the plasma membrane. During the repair, the vesicles release their mucus into the lumen of the large intestine and helps decrease diverticulitis.
what does the microbiota in the colon ferment soluble fiber into and what are the benefits?
Soluble fiber is fermented by the colonic bacteria into organic acids like butyric acid. Organic acids provide energy and carbons, and they also are used as signals to the GI track and body (signals can effect things like the immune system and mood)