Digestion and Metabolism Flashcards
cholecystokinin (CCK) causes the gallbladder to do what
contract and secrete concentrated bile
What does the concentrated bile secreted by gallbladder caused by CCK do?
emulsify fats
CCK caused the pancreas to secrete what?
an enzyme rich juice which will aid in digestion.
What is one of the major stimuli for Cholecystokinin?
presence of fats in the small intenstine or duodenum
Secretin caused the liver to do what?
secrete a dilute bile to help neutralize a low PH in the Duodenum or SI
secretin will cause the pancrease to secrete_____
a bicarbonate rich secretion or juice to help neutralize
When is secretin secretion needed?
when there is a low PH in the duodenum or SI
What is Chyme
Semifluid, creamy mass consisting of partially digested food and gastric juice
Protein digestion begin in the
stomach
fat digestion occurs primarily in the
small intestine
The only stomach function that is essential to life is
the secretion of intrinsic factor
intrinsic factor is required for
intestinal absorption of B12
What does secretin do?
helps raise the PH in the SI
secretin and CCK are usually secreted at the same time. T or F?
True
what makes up feces
undigested food, bacteria, water, epithelial cells,
If your thoracic duct is blocked what would not be absorbed
fats, fat soluble vitamins
fats, fat soluble vitamins gets absorbed through _________ which is part of the lymphatic system
thoracic duct
what is chyle?
fatty, milky white lymph that drains from the fingerlike villi of the intestinal mucosa
which hormone stimulate gastric secretions
gastrin
The more gastric secretions the more ___________ in the digestive system
motility
the 4 tunics in order from lumen side to outside
mucosa, submucosa, muscularis externa, serosa
The 4 tunics in order from outside to inside
serosa, muscularis, submucosa and mucosa
If a child swallowed a penny which layer of the alimentary canal would the penny be touching?
The mucosa layer
If a child swollows a penny and needs surgery to remove it, what is the first layer of the alimentary canal to be cut?
serosa
mucosal layer has what kind of cells?
epithelial cells and nerves
the submucosal layer has
glands and nerves
muscularis mucosa is made up of
muscles and nerves
serosa is mostly
outer connective tissue
mucosa layer and the submucosa are both innervated by
nerves
What do the nerve plexus in the muscularis and submucosa layer do?
They increase secretions and motility in that area.
when the nerves are in the glands of the alimentary canal it will cause
secretions
when the nerves are in the muscle of the alimentary canal it will cause
motility
what part of the CNS governs the nerve innervation in the alimentary canal?
Parasympathetic nervous system
role of pyloric sphincter
Valve of the distal end of the stomach that controls food entry into the duodenum.
if the pyloric sphincter was closed what would it prevent
the chime from going in the small intestine
ileocecal valve
Site where the small intestine joins the large intestine.
ileum
Terminal part of the small intestine; between the jejunum and the cecum of the large intestine.
Where does the small intestine begin and where does it end?
pyloric sphincter, ileocecal valve
where does the small intestine join the large intestine
ileocecal valve
Bile leaves the liver lobes through the
right and left hepatic ducts.
what does the fusing of the right and left hepatic duct create?
the common hepatic duct
what does the common hepatic duct, travel downward towards?
the duodenum
the common hepatic duct travels downward towards the duodenum fusing with the cystic duct and drains the gallbladder to form the
bile duct
The common bile duct plus the pancreatic duct goes into the
small intestine
Esophagus is just a tube going from oral cavity to stomach made up of
stratified squamous.
What organ in gut does everything but does NOT make digestive enzymes
the liver
what is a hepatocyte
platelike, hexagonal (six sided) liver cells
hepatocytes have large amounts of
rough and smooth ER, Golgi apparatus, peroxisomes, and mitochondria
hepatocytes in the liver can
secrete bile, process bloodborne nutrients in various ways, store fat soluble vitamins, detoxify.
what can’t the hepatocytes do?
they do not make digestive enzymes
what does the liver produce that helps with the emulsification of fats?
bile
what are the three parts of the small intestine
duodenum, jejunum, ileum
anatomy of the large intestine
ascending colon, transverse colon, descending colon, sigmoid colon, rectum, anus.
duodenum
First part of the small intestine.
what are the main types of gland cells of the stomach
parietal, chief and enteroendocrine cells
what do the parietal cells of the stomach secrete?
hydrochloric acid
what do chief cells secrete?
pepsinogen which is the inactive form of pepsin.
what does enteroendocrine cells secrete
hormones like gastrin
pepsinogin needs to get cut or cleaved to pepsin in order to
be activated into pepsin.
The activation process of pepsin involves
removing a small peptide fragment from pepsinogen, causing it to change shape and expose its active site
liver lobules have corners what are they called
portal triad
low PH from the hydrochloric acid caused what to be activated
pepsinogen
pepsin is there to help begin
protein digestion
At each of the six corners of a lobules in the liver is a portal triad (portal tract region), so named because it contains three basic structures, what are they
A branch of the hepatic artery, a branch of the hepatic portal vein, and a bile duct.
in the portal triad in the liver, what does the branch of the hepatic artery do?
supplies oxygen-rich arterial blood to the liver
in the portal traid in the liver, what does the branch of the hepatic portal vein do?
carries venous blood laden with nutrients from the digestive viscera
Blood from both the hepatic portal vein and the hepatic artery proper percolates from the triad regions through these sinusoids and empties into the
central vein
From the central veins blood eventually enters the hepatic veins, which drain the liver, and empties into the
inferior vena cava
central vein
the middle part of the liver cell or hepatocyte.
The central veins of all the liver lobules unite to form the
hepatic vein which comes out of the liver and goes into the inferior vena cava
the hepatic vein empties into the
inferior vena cava
what are the three main roles of mesentery
to provide routes for blood vessels, lymphatics, and nerves to reach the digestive viscera. They hold organs in place and they can store fats.
What is a mesentery ?
a double layer of peritoneum—a sheet of two serous membranes fused back to back—that extends to the digestive organs from the body wall.
what are the specialized mesentary that store fats
greater or lesser omenta
what is the role of the mucous in the stomach
to protect the stomach from a low PH
The cephalic phase of gastric secretion happens when
before food enters the stomach
The cephalic phase is all in the head, it can be positive or negative it is triggered by aroma, taste, sight or thought. T or F?
True
The gastric phase is initiated by hormonal mechanisms when the
food or chyme reaches the stomach.
if the PH of the chyme that reaches the stomach has a PH lower than 2 what happens?
there is an inhibitory response to digestion until the ph is dealt with.
if the PH of the chyme that reaches the stomach has a PH higher than 2 what happens?
There is a stimulatory response which increases secretions and motility.
the small intestine doesn’t have a lining of mucous like the stomach, so what needs very strict control
PH
What is the function of the small intestine
almost all of the digestion happens in the small intestine and absorption
what is the function of the large intestine
absorption of water and where the body makes feces
what is bile
it’s a steroid that comes from cholesterol
What does bile do?
bile emulsifies fats and increase the surface area.
does bile have any digestive function
no. it simply emulsifies fats
what stimulates the secretion of bile?
either CCK which causes bile from the gallbladder or secretin which caused bile form the liver depending on whether you need concentrated or dilute
if you don’t have gallbladder and you don’t have concentrated bile where does your bile come from?
liver. you’ll have a dilute bile and It won’t emulsify as well but will suffice
what is the stimulus of the defecation reflex?
stretching of the rectum - stretch reflex.
for the defecation reflex you have both the
external and internal anal sphincter relax.
what kind of muscle and control is in the external sphincter
voluntarily controlled skeletal muscle
what kind of muscle and control is in the internal sphincter
involuntarily controlled smooth muscle.
What are the body’s most concentrated source of energy?
Fats
Most products of fat digestion are transported in lymph in the form of fatty-protein droplets called
chylomicrons
water-soluble lipoprotein droplets
chylomicrons
Micelles
collections of fatty elements clustered together with bile salts in such a way that the polar (hydrophilic) ends of the molecules face the water and the nonpolar portions form the core.
Micelles accelerate lipid digestion and
are essential for the absorption of it’s end product.
Without bile, lipids could not be completely digested during the time food spends in the small intestine. True or False?
True
chylomicrons are emptied into the venous blood via the
thoracic duct, which drains the lymphatics of the digestive viscera.
what stimulates saliva secretion
food, smell, thought, chewing, time of day, cravings, conversation about food, etc.
where is the ileocecal valve ?
Between the cecum and the large intestine.
What does the ileocecal valve do?
Controls movement into the large intestine.
_______ are fingerlike projections of the mucosa in the small intestine
Villi (vil′i; “tufts of hair”)
In the Small Intestine, Microvilli are long, densely packed cytoplasmic extensions of the absorptive cells of the mucosa that give the mucosal surface a fuzzy appearance called the
brush border
The plasma membranes of the microvilli bear enzymes referred to as brush border enzymes, which ______________
complete the digestion of carbohydrates and proteins in the small intestine.
The most important brush border enzymes are ____________
dextrinase and glucoamylase
What enzyme will you not have in the brush border?
Amylace
What the two forms of amylace
salivatary and pacreatic
What begins the break down of carbs in the mouth
salivary amylace
Where does carbohydrate break-down pick up again in the gut and why?
pacrease becasue of pacreatic amylace
what is the PH in the mouth
7
what is the PH in the stomach
1-4
What is the PH in the small intestine
closer to 7
What is the PH in the small intestine
closer to 7
if the PH in the duodenum is less than 2 what happens?
that decreases the gastrin
if the PH in the duodenum is more than 2 what hapens
increases gastrin release
what is catabolic
a break-down reaction
what is anabolic
synthesis reaction
metabolism is
the sum of all reactions
Starch is
how plants store carbohydrates
essential amino acids
you don’t make it enough or not at all and need to supplement through diet
fat soluble vitamins are
absorbed with fats and stored with fats, ADEK and you can overdose on those
cholesterol is a lipid more specifically
it is a
steroid
Cholesterol is a precursor to all other steroids. T or F?
True
if you don’t have cholesterol in your diet what organ will make it for you?
your liver will make cholesterol.
what is the role of NADH – and FADH2
they carry electrons to the electron transport chain.
What are like taxi cabs for electrons?
NADH and FADH2
when is lactic acid produced?
when you have low oxygen levels
when is pyruvate produced?
When you have enough oxygen
glycolysis
converts (or breaks down) glucose to two pyruvic acid molecules. All parts of this process are reversible except for the first part.
what is the major role of acetyl CoA?
enter the Kreb cycle
beta oxydation is when you
how you breakdown lipids breakdown two carbons at a time from fatty acids. those two carbons are made into acetyle coa
when does the body make ketones
when you breakdown too many fatty acids which will increase acetle coa which will up the ketones
the acetyl CoA, beta osydation and ketone process is all
reversible
oxidative deamination of amino acids
breakdown amino acids for energy because they enter the kreb cycle.
aerobic means
with oxygen
anaerobic means
without oxygen
aerobic respiration (with Os) will produce how many ATP
34 ATP
anaerobic respiration makes how many ATP
4 ATP
what is basal metabolic rate? BMR
Rate at which energy is expended (heat produced) by the body per unit time under controlled. often referred to as the “energy cost of living”.
how will have a higher BMR man or woman?
man
who will have a higher BMR old person or young person?
young person
what is the energy yield per gram for protein
1 gram of protein yields 4 kilocalories
what is the energy yield per gram for carbohydrates
1 gram of carbohydrates yields 4 kilocalories
what is the energy yield per gram for fat
1 gram of fat yields 9 grams of kilocalories
fat or triglyceride is the major energy storage molecule because
for each gram your get twice as much energy source
krebs cycle
Aerobic metabolic pathway occurring within mitochondria, in which food metabolites are oxidized and CO2 is liberated, and coenzymes are reduced. Also called the Krebs cycle.
The __________ is the serous membrane that covers most digestive organs.
mesentery
visceral peritoneum
parietal peritoneum
omenta
visceral peritoneum
The __________ circulation collects nutrient-rich venous blood draining from the digestive viscera.
pulmonary
splanchnic
enterohepatic
hepatic portal
hepatic portal
From the esophagus to the anus, the walls of the alimentary canal have the same four basic tunics. The __________ is the outermost layer of the walls of the intraperitoneal organs.
serosa
submucosa
mucosa
muscularis
serosa
The function of the hepatic portal circulation is to ________.
- distribute hormones throughout the body
- return glucose to the general circulation when blood sugar is low
- carry toxins to the kidney for disposal through the urinary tract
- collect absorbed nutrients for metabolic processing in the liver
collect absorbed nutrients for metabolic processing in the liver
The sheets of peritoneal membrane that hold the digestive tract in place are called ________.
lamina propria
mucosal lining
serosal lining
mesenteries
mesenteries
From the esophagus to the anal canal, the walls of every organ of the alimentary canal are made up of the same four basic layers. Arrange them in order from the lumen.
serosa, mucosa, submucosa, and muscularis externa
submucosa, serosa, muscularis externa, and mucosa
mucosa, submucosa, muscularis externa, and serosa
muscularis externa, serosa, mucosa, and submucosa
mucosa, submucosa, muscularis externa, and serosa
In the enteric nervous system, a long reflexive pathway has an advantage over a short reflexive pathway in the fact that ________.
long reflexive pathways can be stimulated by things outside of the GI tract
Your patient has had a total gastrectomy (removal of the stomach). Which of these potential problems are you MOST concerned about?
- Excessive bleeding as a result of absent clotting factors in the blood.
- Inability to digest starch because of the –absence of amylase
- Anemia
- Inability to tolerate fats because of absent bile salts
anemia
Which of the following is NOT a function of saliva?
Saliva moistens food and helps compact it into a bolus.
Saliva contains enzymes that begin the chemical breakdown of proteins.
Saliva cleanses the mouth.
Saliva dissolves food chemicals so that they can be tasted.
Saliva contains enzymes that begin the chemical breakdown of proteins.
What event triggers the opening of the gastroesophageal sphincter?
peristalsis in the esophagus
pH changes in the esophagus
constriction of the upper esophageal sphincter
detection of nutrients in the esophagus
peristalsis in the esophagus
Another term for swallowing is deglutition.
True
False
True
The soft palate reflexively opens the nasopharynx to allow the passage of food, which is now called a bolus.
True
False
False
Which layer of the stomach contains the gastric pits that secrete mucus, acid, and digestive enzymes?
mucosa
Which area of the stomach directly adjoins the small intestine?
pylorus
The __________ phase of gastric secretion begins as chyme enters the duodenum.
gastric phase
cephalic
reflux
intestinal
intestinal
An obstruction by a gallstone is least likely to occur in the ______.
common hepatic duct
bile duct
cystic duct
lumen of the hepatopancreatic sphincter
common hepatic duct
The blood flow into the liver is via the ___________ and ___________, while blood exits the liver via the ______________.
hepatic portal vein; hepatic artery; hepatic vein
The major outcome that occurs through mechanical digestive activities is
an increase in the surface area of food by breaking it into smaller fragments
propulsion of materials via peristalsis
chemical breakdown of food molecules
enteric reflex activation
facilitation of absorption
an increase in the surface area of food by breaking it into smaller fragments
The stimulus for the release of pancreatic enzymes is
gastric distention
gastrin
bile salts
the presence of chyme in duodenum containing protein and fats
secretin
the presence of chyme in duodenum containing protein and fats
Protective collections of lymphocytes and macrophages that occur in the ileum are the gastric pits the Peyers patches the intestinal crypts the muscularis mucosae the muscularis externa
the Peyers patches
During deglutition, the bolus passes into the stomach from the esophagus through the
gastroesophageal sphincter
The primary chemical digestion that takes place in the stomach is
proteins
Which sequence below represents the correct layering of the GI tract organs’ walls?
mucosa - submucosa - muscularis externa - serosa
Which substance or occurrence would directly decrease gastric activity?
distention of duodenum
Which of the following is a characteristic of the large intestine? I
it contains a large number of bacteria
The propulsive function which occurs in the esophagus is called
peristalsis
The function of a lacteal is to
absorb lipids
Swallowing reflexes begin when receptors are stimulated by food in this structure:
pharynx
This structure is a modified portion of the small intestines mucosa which greatly increases the absorptive surface area.
villa
During the intestinal phase of gastric regulation
the stomach is initially stimulated, and later inhibited
Which regulatory chemical stimulates gastric gland activity and motility?
gastrin
Which coenzymes are reduced in both glycolysis and the Kreb’s cycle?
NAD
Most vitamins and minerals function as
coenzymes in the body
The cell respiration process in which carbon dioxide is removed from a carbon source is
Krebs cycle
The process in which glucose is converted to a storage form occurs where?
in the liver
The process of cellular respiration
release energy stored in chemical bonds
A major means for conserving heat is
vasoconstriction of cutaneous blood vessels
Essential nutrients
can not be synthesized in the body
In cellular respiration, how many ATP molecules are produced for each glucose metabolized?
36-38
The thermoregulatory center is located in the
hypothalamus
Which event would occur in the absorptive state?
insulin release
Four main factors in the duodenum cause it to put the “brakes” on gastric secretion
Distension of the duodenum or the presence of acidic, fatty, or hypertonic chyme
Fats and carbohydrates are oxidized directly to produce cellular energy, whereas amino acids can be used to supply energy only after being converted to a
citric acid cycle intermediate
Insulin directs essentially all events of the absorptive state
True
Glycolysis is an ____________ process.
anaerobic
glycolysis does not use oxygen and occurs whether or not oxygen is present. T or F?
True
The final products of glycolysis are two molecules of _______, two molecules of __________, and two ____.
pyruvic acid, reduced NAD+ (NADH), and two H+.
The citric acid cycle (or Krebs cycle) is the next stage of glucose oxidation and is named for its first substrate. The citric acid cycle occurs in the
mitochondrial matrix and is fueled largely by pyruvic acid produced during glycolysis and by fatty acids resulting from fat breakdown.
essential nutrients
cannot be made by the body and must be ingested. OR we might make it but we don’t make enough of it.
carbs are
short term energy
how do we store carbs?
we store them as glycogen
how do plants store carb?
starch
plants use carb in their cell walls which is called
cellulose or we call it fiber
lipids are
long term energy
how many amino acids are essential?
9
how many amino acids are non-essential
11
nitrogen balance
the rate of protein synthesis equals the rate of protein breakdown and loss
positive nitogren balance
you take in more than you breakdown - pregnant or growing children
negative nitrogen balance
you breakdown more than you take in - starvation.
The energy released from a catabolic reaction may be used to drive a
anabolic reaction
redox reaction is when
electrons are moved from one molecule to the next
Like glycolysis, none of the reactions of the citric acid cycle use oxygen directly. This is the exclusive function of the ____________ , which carries out the final catabolic reactions that occur on the inner mitochondrial membrane.
electron transport chain
basal metabolic rate
basic amount of ATP that you need to maintain your body function at rest
amylase breaks down
starch
