chap 41 Flashcards
which cells are responsible for secreting the components of gastric acid
- chief cells
- parietal cells
which of the following are components of gastric acid
- amylase and pepsin
- HCl and bile
- HCl and amylase
- HCl and pepsin
HCl and pepsin
the breakdown of starch by amaylse is the example of
chemical digestion
which large biological molecules undergo chemical digestion in the oral cavity
carbohydrates
which large biological molecules undergo chemical digestion in the stomach
proteins
which of the following are part of the alimentary canal?
- small intestine
- liver
- gallbladder
- pancreas
small intestine
which large biological molecules undergo chemical digestion in the small intestine
fats
proteins
carbohydrates
nucleic acids
Which classes of large biological molecules is digested by enzymes from the pancreas?
fats
proteins
carbohydrates
nucleic acids
herbivores eat what?
plants and algae
carnivores eat what?
other animals
omnivores eat what
plants, algae, and other animals
what animal food group category are humans in
omnivore (plants, algae, and animals)
most animals are oppertunistic eaters, what does this mean
they eat what they can when the can;
they eat food outside their diet when their usual foods aren’t available
cells, tissues, organs, and animals depend on what to drive their cellular bodily process
ATP, energy needed for life
what substrates are needed to generate ATP during cellular respiration
carbohydrates, proteins, lipids
why must you digest/ingest food?
- provide ATP
- generate raw materials needed for biosynthesis of large biological molecules
- obtain essential nutrients
what is a major dietary source of organic carbon?
carbohydrates
what is a major dietary source of organic nitrogen?
proteins
what are the 4 essential nutrients
amino acids
fatty acids
vitamins
minerals
what is an essential nutrient
nutrients that animals need, but can’t synthesize
why do animal cells need essential nutrients
the molecules are required for many biosynthetic reactions within cells
how are most enzymes derived
from diet, body can’t make them
how many amino acids do humans need in their diet
8
what type of food contain all 8 amino acids
animal products (meats, eggs, cheeses)
what amino acids do human infants require in addition to the 8
histidine
how do essential nutrients generally function
substance that enzymes work on
coenzymes
cofactors
why are fatty acids essential to animal cells
the cell can’t synthesize them and they are needed to build things
how many essential vitamins are there
13 vitamins (that can’t be synthesized by animal cells)
whats the function of water soluble vitamins
production of nucleic acids and red blood cells
what are the symptoms of deficiency of water soluble vitamins
anemia, numbness, loss of balance
whats the function of fat soluble vitamins
helps body absorb and use calcium and phosphorus
what are the symptoms of deficiency of fat soluble vitamins
rickets in children
bone softening in adults
how are water soluble vitamins dietary claimed
meats, eggs, dairy products
how are fat soluble vitamins dietary claimed
egg yolk, sunlight, dairy products
How does rickets impact the the shape of a femur
it is bowed
how is calcium derived in diet
diary products, green vegetables
how is sodium derived in diet
table salt
how is chloride derived in diet
table salt
how is iodine derived in diet
seafood, dairy products, iodized salt
what is the difference between vitamins and minerals
vitamins are organic molecules.
minerals are inorganic molecules
what is goiter
a disease due to frequently not getting enough iodine
why is iodine deficiency less common in the united states
a lot of salt is consumed in our diets
the american diet takes is how much more salt than what is actually needed
20x more
excessive salt consumption contributes to what
high blood pressure
what causes malnutrition
under-nutrition
deficiencies in essential nutrients
what is malnutrition
failure to obtain adequate nutrition
under-nutrition is commonly found in?
eating disorders
what are potential effects of undernutrition
uses up stored fats body breaks down own proteins muscle decreases and brain becomes deficient death damage can be irreversible
whats an example of essential nutrient deficiencies
populations on rice diet frequently deficient in vitamin A (causing blindness/death)
what is essential nutrient deficiency
long term absence of 1+ essential nutrients
what are potential effects of essential nutrient deficiency
deformities
disease
death
what are the 4 stages of food processing
ingestion
digestion
absorption
elimination
what is ingestion
act of eating or feeding
what is digestion
food is broken down into molecules that are small enough for the body to absorb
mechanical digestion
breaks food into smaller pieces which increases the surface area
chemical digestion
molecules breaking down into their monomers through hydrolysis
what is absorption
uptake of small nutrient molecules into blood or lymph vessels
what is elimination
passage of undigested material out of the digestive system
alimentary canal is also known as
gastrointestinal tract
accessory organs
An organ that helps with digestion but is not part of the digestive tract
peristalsis
alternative waves of contractions and relaxation of smooth muscle
sphincters
muscles that form ring like valves that close off compartments within the alimentary canal
what is the function of peristalsis
to move food through the alimentary canal
what is the function of sphincters
regulate the passage of material through different parts of the different parts of the alimentary canal
what is the digestive system in the oral cavity
chewing food nervous reflex saliva from salivary glands amylase -- hydrolase starch, glycogen --> small polysaccharides and disaccharides
saliva contains
mucus, buffers, antibacterial agents
what is mucus
mixture of water, salts, cells, mucins (slippery glycoproteins)
what are buffers
neutralize acids and protects teeth
what are antibacterial agents
lysosomes that destroy microorganisms that enter the mouth with food
what is the tongue’s function
evaluates ingested material and process it for swallowing
what is the bolus
ball of chewed food shaped by the tongue
what occurs when not swallowing a bolus
- esophageal sphincter muscle is contracted
- epiglottis is up and glottis is open
- air can easily enter the lungs via trachea
what occurs when the bolus reaches the throat region
- swallowing reflex is triggered
- epiglottis tips over glottis which prevents food from entering the trachea
- esophageal sphincter relaxes allowing bolus to enter the esophagus
what occurs after the bolus enters the esophagus
- esophageal sphincter muscle contracts
- peristalsis moves bolus down the esophagus and towards the stomach
breaking down amylase is an example of
chemical digestion
which large biological molecule undergoes chemical digestion in the oral cavity
carbohydrates
the stomach is lines with
gastric glands w/ several diff types of cells
function of mucus cells
secrete mucus that lubricates and protects cells of the stomach from harsh chemicals
what is the function of chief cells
secrete pepsinogen, an inactive form of the protease, pepsin
what is the function of pepsin
an enzyme that digests peptide bonds and break proteins into small polypeptides
what pH does pepsin have to be at to work
pH 2
what is the function of the parietal cells
secrete HCl to:
activate pepsinogen to pepsin
kill bacteria
denature proteins
what is the function of g-cells
produce the hormone gastrin which stimulates production of gastric juices
are the epithelial cells that line the stomach vulnerable to acid pH and pepsin digestion
yes, but the cells secrete enough mucus that protects against self-digestion
how often to epithelial cells replicate
replaced every 3 days
what is a gastric ulcer
damaged parts of the stomach lining
what is the cause of stomach ulcers
bacterial infections by H pylori
what are the cells that line the stomach
epithelial cells
how are stomach ulcers treated
with antibiotics
what is the only enzyme that can break down in the stomach
pepsin
where does most chemical digestion take place
SI
how long is the SI in length
6 meters
what is the duodenum
first 25 cm where chyme from stomach mixes with digestive juices from pancreas, liver, and gallbladder
what does the SI get its name from
its diameter not its length
the pancreas has enzymes that help digest what
proteins, carbohydrates, lipids, and nucleic acids
pancreatic enzymes work best at what pH
pH 7-8
Where is bile released to for digestion
gallbladder
what produces bile
liver
where is bile stored
gallbladder
what is bile
fluid that aids in digestion
what are bile salts
salts that act as detergents and increase surface area for digestion
what part of the digestive system contains bicarbonate to neutralize the acidity of chyme
pancreas
what aids in the destruction of red blood cells that are no longer functional and breaks down toxins
bile
The absorption of molecules takes pace where in the SI
lleum
what is the purpose of all the folds in the small intestine
to increase surface area
purpose of microvilli
increase the surface area of each epithelial cell to increase the total capacity for nutrient absorption
describe absorption in the small intestine
movement of molecules from lumen through epithelial cells into the blood capillaries or lacteal
purpose of fructose
facilitates diffusion to cross epithelial cells
AAs, glucose, small peptides require energy for what
use active transport mechanisms to cross epithelial cells
what keeps fat droplets from coalescing in the lumen during absorption
bile salts
what digests triglycerides into fatty acids and monosaccharides during absorption
pancreatic lipase
after fatty acids and monoglycerides diffuse into epithelial cells, what happens during absorption
recombine into triglycerides
what are assembled within the epithelial cells that line in the SI during absorption
chylomicrons
what are chylomicrons
large water-soluble globules that can’t enter the blood vessels found in the villus
how do chylomicrons leave epithelial cells
exocytosis and enter lacteals
after chylomicrons circulate through lymph vessels, where do they go next
pass through the left subclavian vein
what do chylomicrons consist of
proteins
cholestrerol
phospholipids
triglycerides
why cant fats enter the capilary system
they are too large
what vessels do fats enter
lacteal vessels
how do monosaccharides, AA, nitrogen bases, ribose, deoxyribose, phosphates enter the heart
villi capillaries –> hepatic portal vein –> liver –> heart
what happens when glucose is in access and and energy is low
glucose is converted to glycogen within liver
how do fats enter the heart
chlyomicrons –> lacteals –> larger lymph vessels in lymphatic system –> large vein –> heart
what regulates the distribution of nutrients to the rest of the body
liver
if there’s not enough food, how does the body adapt
the body breaks off part of the glucose that is already stored
which of the large biological molecules are digested in the large intestine
none
whats the function of the large intestine
completes the reabsorption of the water that began in the small intestine
what is feces
waste of the digestive system
feces contain cellulose to help function in what
to move food along the alimentary canal
the bacteria in feces do what?
- live off the unabsorbed organic material within the gut
- generates gases
- synthesizes vitamins
rectum function
terminal portion of the intestine that stores feces
whats the inner sphincter of the rectum
involuntary muscle
whats the outer sphincter of the rectum
voluntary muscle
microbiome function
the collection of bacteria that inhibit our guts
what is a hormone
a chemical signal that is synthesized by an endocrine to trigger a response in the target cell
how are non-target cells involved in the hormonal regulation of digestion
they aren’t, they aren’t able to receive a chemical signal
what are the hormones that play a role in the coordination of the digestive process
gastrin
secretin
cholecytskinin
what are the hormones that play important roles in regulating blood glucose levels
insulin
glucagon
what is the function of gastrin
coordinates digestion within the stomach
what does the stimulus do when food arrives in the stomach
- triggers release of gastrin from g-cells to blood stream
- returns to stomach and acts on target cells to stimulate the gastric juices
- stimulus is removed after food is removed
what is the function of the CCK in the small intestine
release of digestive enzymes from pancreas and bile from gallbaldder
what is the function of the secretin in the small intestine
increases release of HCO3- that neutralizes chyme (on pancreas)
both secretin and CCK work together to operate what function
act on the stomach to inhibit peristalsis and secretin of gastric juices
what slows down digestion of the chyme within the stomach before it enters the SI
cck and secretin
Type 2 diabetes is characterized by a failure of target cells to respond normally to insulin. What best describes the resulting glucose levels in a type 2 diabetic and strategy for treatment
high blood glucose levels, that increase sensitivity to insulin
insulin targets what what cells?
targets muscle and liver cells
what stimulates glucose uptake and stimulates glucagon synthesis
insulin
what targets liver cells
glucagon
what stimulates glycogenolysis and breaks down glycogen
glucagon
