lecture 6c Flashcards
Feeding and Digestion: Intestinal Morphology and Function
gastric
stomach
enteric
intestine and stomach
most ancient organ system
digestive along with integumentary
define blastopore and archenteron
During gastrulation, the archenteron develops into the digestive tube, with the blastopore developing into either the mouth (protostome) or the anus (deuterostome).
digestion
the physiological function of processing ingested food into smaller molecules that can be absorbed by the body.
absorption
the physiological process of bringing molecules into the living tissues (in this case, from the lumen of the intestine).
incomplete digestive sys
blind-end sac.
One opening serves the function of both mouth and anus.
This was the first type of gastrointestinal tract to evolve.
The complete digestive tract
- has an opening at each end
- may have contributed to the evolutionary success and diversification of animals
headgut
consisting of the lips (in mammals) mouth, tongue, and pharynx
name 4 parts of the foregut
esophagus
stomach
crop (some species)
gizzard
midgut
consisting of the small intestine.
hindgut
has the large intestine
crop vs gizzard
crop for “:storing crops”
g for gizzard and grounding
They seem to be the same structure but they perform different functions. The crop is closer to the head than the gizzard is. The crop is where food passes into when it leaves the esophagus. The gizzard, which is the next stop for food after leaving the crop, is where food is ground.
ex of incomplete digestive sys
cnidarian (jelly fish)
ex of complete digestive sys
earthworm
grasshopper
bird
carnivore gi tract vs herbivore gi tract
carnivore is smaller and simpler
fermentation
is a cellular process that is anaerobic. It is the means used by certain cells to convert organic food into simpler compounds.
why is intestinal microbiome disruption dangerous for herbivores?
they need proper symbiois or else it could be a can be a serious, sometimes lethal, insult.
ex: when certain antibiotics are given to them
benefit of microbes in herbivores
collectively to the microscopic organisms, including bacteria, fungi, protozoa, and viruses.
== helps in breaking things down into simpler materials
headgut
mouth and associated structures
name the 2 mouthparts that anthropods (crabs) as their headgut
- chelicerae
2. mandibles
define chelicerae
used to hold and crush prey.
define homodont and give an example
teeth are relatively uniform in shape
ex: vertebrates
define Polyphyodont and give an example
teeth are constantly lost and replaced.
ex: Fish, toothed amphibians, and reptiles are polyphyodonts.
how have teeth helped headguts? there are 4
conical teeth of different sizes
life process of fish teeth such as sharks
start out as homodont teeth with conical shape but later in life ends up with polydont because it replaces teeth constantly
life process of Tuataras, Lizards, Snakes, and crocodilians
start out as homodont teeth with conical shape but later in life ends up with polydont because it replaces teeth constantly
Viperid and Elapid vs colubrid snakes
colubrid (Columbia) has rear fangs
the other snakes have elongated fangs
either way, the fangs are used to release venom
birds do not have teeth but rather
these bills are from nat selection and varies by diff type of bird
diphyodonts and give ex
teeth are replaced only once.
deciduous (“baby”) teeth fall out
permanent teeth
ex: humans
heterodonts and giv ex
pertains to animals where teeth are differentiated into different forms such as incisors, canines, premolars, and molars.
ex: humans
incisors
at the front of the mouth have a sharp biting surface and are used for cutting or shearing food into small chewable pieces.
canine teeth
They have a sharp, pointed biting surface. Their function is to grip and tear food
premolars
flat biting surface. Their function is to tear and crush food.
molars
used to crush food
what are ceceans
dolphins whales and porpoises (aquatic marine animals)
what type of teeth do ceceans have?
secondarily reverted to the homodont condition.
hypsodonts
Teeth grow continually throughout the animal’s life.
Teeth wear against each other during chewing, maintaining proper length.
Correct dental occlusion is critical for maintenance of healthy tooth length.
esophagus
pushes food from the headgut into the stomach
define stomach and what is ph
breaks up food with muscular action, acids, and digestive enzymes.
stomach environment may be highly acidic (pH ~ 0.8 in humans)
stomach secretes pepsins to digest proteins
gall bladder
stores bile, a lipid emulsifier
secretes digestive enzymes (exocrine function) and insulin (endocrine function)
pancreas
4 functions of liver
bile production and excretion
bilirubin excretion (breaks down heme)
cholesterol, hormone, and toxin excretion
protein, carbohydrate, and lipid metabolism
the midgut contains what percentage of the transverse colon?
65%
the hindgut contains what percentage of the transverse colon?
35%
name 2 functions of the hindgut?
it is the large intestine
reabsorbs water and electrolytes
stores fecal matter between defecations
cloaca
A cloaca is an orifice through which urine and feces are eliminated in birds, reptiles, amphibians, and a few branches of the mammal family tree. It also serves a reproductive function like the vagina in females of these species, and also performs the function of sperm ejaculation in males of some species.
Arthropods
invertebrates
chitin
a fibrous substance consisting of polysaccharides and forming the major constituent in the exoskeleton of arthropods and the cell walls of fungi.
what does arthopods and cloacas have in their foregut and hindgut but not in midgut?
chitin
Malpighian tubules
collect nitrogenous waste for insects
They then empty waste into the intestine at the midgut/hindgut junction
mucosa
gut epithelium+ conn tiss
Gut wall muscles are arranged in
an outer layer of longitudinal muscles
an inner layer of circular muscles
peristalis
wavelike constrictions of the intestine that push food caudally towards the anus/cloaca
segmentation
organized circular muscle constrictions that push food back and forth in the intestine.
submucosa
blood vess and lymph vess
illeus
is a pathological condition in which peristalsis ceases.
If not treated, this can result in intestinal obstruction and sometimes life-threatening complications.
dysbiosis (not symiosis)
an imbalance of the normal microbial flora.
static intestine
fertile ground for overgrowth of harmful bacteria, as chemical conditions in the lumen change.
==== can cause dysymbiosis
pilli
increases SA
reactor
a vessel used to perform industrial chemical or microbial reactions to produce various products.
name 3 diff types of reactors
batched reactor
contin flow reactor
contin flow with mixed
batched reactor
processes one batch at a time, emptying out its products between batches.
Animals with a simple gut are somewhat analogous to this type of reactor like snakes
contin flow reactor (no mix)
tube in which batches line up in the order in which they were placed in the reactor.
like in carnivores and omnivores
Multiple meals per day travel through the intestine, but do not mix.
contin flow reactor ( mix)
tube with an intervening, enlarged vessel that allows mixing of batches that have been added to the reactor at different times.
The intestine of an herbivorous fermenter functions like a this type of reactor.
Microbial fermentation works best on
mixture of previously ingested food (already colonized by microbes) and recently ingested food.
cud
partly digested food returned from the first stomach of ruminants to the mouth for further chewing
ruminants vs pseudoruminants
ruminants have 4 chambers whereas the pseudoruminants have 2 or 3
the microbes involved are non ancidic and can live up to 10 to the tenth population
has a honeycomb-like appearance
involved in separation of particles of different sizes
Cooked, it is known as tripe
reticulum
omassum
involved in water re-absorption
highly folded ("like the pages of a book")Abossum
acidic
essentially similar to the monogastric animal stomach
secretes a cocktail of digestive enzymes
Chymosin
produced by newborn ruminant animals in the lining of the abomasum to curdle the milk they ingest, allowing a longer residence in the bowels and better absorption
Bc VFAs constantly move down their concentration gradient
through the rumen epithelium into the bloodstream and on to the liver
Effects will be VFAs constantly move down their concentration gradient
through the rumen epithelium into the bloodstream and on to the liver
factors of the enteric fermentation
CO2
CH4
amino acids
b vitamins
eff of corn and soy
raises methane
eff of grass
lowers methane which lowers energy which will limit the animal’s growth
where is ammonia is converted to urea via the ornithine/urea cycle ?
liver
Urea Nitrogen Salvaging (UNS) factors. there are 4
- -maintenance of nitrogen balance in ruminants
- -regulation of blood pH
- -water conservation in desert herbivores
- -maintenance of lean mass in hibernating mammals
define midgut fermenters and give two examples of herbivores that do this?
have expanded part of the small intestine to house mutualistic, cellulose-digesting microbes.
ex: fishes and insects
name the three acids that VFAs produced are primarily
acetic
propionic
butyric
why do Termites rely on ancient flagellate (protist with endings as mypha) symbionts, aneurobic bacteria, and archaens?
to ferment cellulose and hemicellulose into usable acetic acid.
why do Termites rely on ancient flagellate (protist with endings as mypha) symbionts, aneurobic bacteria, and archaens?
to ferment cellulose and hemicellulose into usable acetic acid.
beetles like to break down cellulose into vfa as well
diff btwn vertebrates and insects
vertebrates can synthesize their sterols
define vfa volatile fatty acids (VFAs)
constantly move down their concentration gradient
through the rumen epithelium into the bloodstream and on to the liver.
metabolized into compounds (e.g., acetyl coenzyme A)
entering the Krebs Cycle.
gives energy
nonpolar nutrients that are absorbed on apical surface
role of midgut fermentations
expanded part of the small intestine to house mutualistic, cellulose-digesting microbes.
cecum
pouch or large tubelike structure in the lower abdominal cavity that receives undigested food material from the small intestine and is considered the first region of the large intestine.
hindgut fermenters
expand either the caecum or the colon (or both) to house fermenting microbes
cecal fermenters
The animal senses the cecotrope passing from the rectum and reaches down to snatch it before it touches the ground.
ex: lagomorphs and rodents
Cecotrophy vs coprophagy
Caecotrophy” is a kind of coprophagy. “Caecotrophy” specifically refers to the ingestion of caecal feces for nutritional purposes. “Coprophagy” refers to the ingestion of feces for any reason, including mental illness.
colipase
binds to lipase, changing it to active form.
secreted by pancreas
inactive form of colipase is
procolipase
pepsin cleaves what and where?
aromatic aa residues at carboxyl
inactive form of peptin
pepsinogen
chymotrypsin
carboxyl end of aromatic residues
active by small intest but inactive by pancreas
apical surface
epithelial cell that is exposed to the body exterior or to the cavity of an internal organ
thin epithelium
increases diff rate
lacteal
tiny lymphatic vessel that absorbs fats
chylomicrons
fats aggregate with proteins to form chylomicrons, which can be transported throughout the body via the bloodstream.
acclimatization
Acclimatization or acclimatisation (also called acclimation or acclimatation) is the process in which an individual organism adjusts to a change in its environment (such as a change in altitude, temperature, humidity, photoperiod, or pH), allowing it to maintain performance across a range of environmental conditions.
