Digestive System Flashcards
food particles are broken down into smaller components which will later be absorbed by the body
digestion
Vertebrate digestive systems (4)
monogastric
avian
ruminants
pseudo-ruminants
have evolved more complex digestive systems to adapt to their dietary needs
vertebrates
have developed a digestive system to eating un-masticated (un-chewed) food
birds
as the word suggest, the digestive system consist of one stomach chamber
monogastric
Examples are humans (digestive system)
monogastric
where process of digestion starts and the intake of food
mouth
play an important role in masticating or physically breaking down food into smaller particles
teeth
in this, there’s enzymes present to chemically break down food
saliva
long tube that connect the mouth to the stomach
esophagus
has an extremely acidic environment (pH 1.5 – 2.5)
stomach
includes enzymes in the stomach, act on food particles and continue the process of digestion
gastric juices
where enzymes from the liver, small intestine, and pancreas continue the process of digestion
small intestines
are absorbed across the epithelial cells lining the walls of the small intestines
nutrients
absorbs moisture from the waste material to make it drier and is compacted into feces that are stored until excreted through the rectum
large intestine
they face special challenges when it comes to obtaining nutrition from food since they do not have teeth
aves
Have to process unmasticated food
aves (birds)
part of the bird that tells their diet, ranging from seeds and insects to fruits and nuts
beak
this ability of birds makes their metabolic rates high in order to efficiently process food while keeping their body weight low
flying
Two chambers of the stomach of birds
proventriculus
gizzard
where gastric juices are produced to digest the food before it enters the stomach in birds
proventriculus
where food is stored, soaked and mechanically ground
gizzard
undigested material forms this that are sometimes regurgitated in birds
food pellets
where most of the chemical digestion and absorption happens in birds
intestine
exit of waste in birds
cloaca
secreted from the kidneys is secreted into the large intestine and combined with waste from the digestive process in birds
uric acid
pouch which stores food in the avian esophagus
crop
first of two stomachs in birds
proventriculus
second stomach of birds
gizzard
some birds swallow this, which are stored in the gizzard, to aid the grinding process
stones or grit
mainly herbivores, such as cows, sheep, and goats, whose entire diet consist of eating large amounts of roughage or fiber
ruminants
Have evolved digestive system to help them process vast amount of cellulose
ruminants
They do not have upper incisor teeth, instead, they use their lower teeth, tongue, and lips to tear and chew their food
ruminants
Four compartments of a ruminant’s stomach
rumen
reticulum
omasum
abomasum
chambers of a ruminant’s stomach may contain these to break down cellulose and ferment ingested food
microbes
true stomach, is the equivalent of the monogastric stomach chamber, where gastric juices are secreted
abomasum
provides larger space and the microbial support necessary to digest plant material in ruminants
four compartment gastric chamber
produces large amounts of gas in the stomach chamber, which must be eliminated
fermentation
part of the four-chambered stomach where they contain prokaryotes and protist that are able to digest cellulose fiber
rumen and reticulum
regurgitates cud from the reticulum, chews it, and swallows it into the third stomach – the omasum
ruminant
part of the four-chambered stomach where water is removed
omasum
part of the four-chambered stomach where the cud is digestive by enzymes produced by the ruminant
abomasum
include camels and alpacas
pseudo-ruminants
➢Eat a lot of plant material and roughage
➢Have three-chambered stomach
➢Do not have rumen, but have an omasum, abomasum, and reticulum
➢Cecum is large
pseudo-ruminants
Pouched organ at the beginning of the large intestine containing many microorganism that are necessary for the digestion of plant materials
cecum
Site where roughage is fermented is digested in pseudo-ruminants
cecum
polymeric sugar molecule that is present in plant cell walls
cellulose
main functions of the digestive system
➢receive ingested food
➢temporary food storage
➢mechanical and chemical breakdown into nutrients
➢absorption of nutrients and water
➢elimination of undigested food and excretory wastes/ by-products
made up of organs that food and liquids travel through when they are swallowed, digested, absorbed, and leave the body as feces
digestive tract
include the mouth, pharynx (throat), esophagus, stomach, small intestine, large intestine, rectum, and anus
digestive tract
the process of taking food, drink, or another substance into the body by swallowing or absorbing it.
ingestion
the process of mechanically and enzymatically breaking down food into substances for absorption into the bloodstream
digestion
the process or action by which one thing absorbs or is absorbed by another.
absorption
the act or process of discharging undigested or waste material from a cell or organism
egestion
have a role in digestive activities and are considered accessory organs
accessory digestive structures
Include the tongue, teeth, oral glands, pancreas, liver, and gall bladder
accesory digestive structures
Differences in the anatomy of vertebrate digestive tracts is often correlated with the
nature of food
abundance of food
Nature of food might be
readily absorbed
requiring extensive enzymatic activity
abundance of food might be (2)
constant food supply
scattered supply
Embryonic digestive tract of vertebrates consist of three regions (3)
foregut
midgut
hindgut
oral cavity, pharynx, esophagus, stomach, and small intestine
which part (foregut, midgut, hindgut)?
foregut
contains yolk or attached yolk sac
which part (foregut, midgut, hindgut)?
midgut
large intestine and cloaca
which part (foregut, midgut, hindgut)?
hindgut
embryonic structure that become the lining of the adult digestive tract and all of its derivatives
archenteron
adds layers of connective tissue and smooth muscles around the archenteron
splanchnic mesoderm
ectodermal invagination forms this, leading into the oral cavity
stomadeum
Becomes the adult buccal cavity and gives rise to teeth enamel, epithelial covering of the tongue, glands, e.g. mucous, poision and salivary, etc., and Rathke’s pouch of anterior pituitary gland
stomadaeum
similar mid-ventral ectodermal invagination, leading into the hindgut
proctodaeum
Forms either a small terminal part of the cloaca in lower vertebrates and rectum in mammals
proctodaeum
reveals general dietary habits of the vertebrates
gastrointestinal tract
There is rapid intake of foods but slower digestion
gastrointestinal tract
Infrequent and fast feeding and drinking behaviors -> food and water must be temporarily stored
t/f?
true
principal storage organ
stomach
Slow digestion > enough absorption > storage capacity of the entire tube is decreased
t/f
false
essential process to release the nutrients from indigestible components and to increase the contact between the food and digestive juices
food reduction
technical term for chewing
mastication
technical term for swallowing
deglutition
Chewing ; Rasping ; Grinding / Oral teeth ; pharyngeal teeth, accessory glands
which group of animals
fishes
Moistening ; softening ; dissolving of food by GI fluids / mouth, stomach, intestines, accessory glands (liver: fat emulsification)
which group of animals
amphibians
Churning and mixing by peristalsis, intestinal segmentation / mouth, stomach, gizzard
what group of animals
reptiles
Grinding ; churning and mixing, intestinal segmentation / gizzard, stomach, intestines, accessory glands
what group of animals
birds
Mastication, moistening and softening, deglutition, peristalsis (esophagus and stomach segmentation), intestinal haustrations, mouth, stomach, intestines, accessory glands
what group of animals
mammals
type of digestion that starts in the stomach and small intestine and involves accessory glands (liver, pancreas)
chemical digestion
in some species of this, the cloaca is absent; intestines and urogenital tracts have separate exit portals
fishes and mammals
happens in the small intestine, folds in the lining of the gut, microscopic villi on the lining of the tube, and smaller microvilli portions of the tube
absorption
Esophagus > stomach (wide fundus, narrow pylorus) > intestine (spiral valve) > rectum/cloaca
which group of animals
fish
Esophagus (short) > stomach > small intestines (duodenum > ileum) > large intestine (short) > urinary bladder > cloaca
which group of animals
amphibians
specialized alimentary canal in reptiles due to the presence of gizzard
crocodiles
Esophagus > stomach (gizzard) > small intestine > large intestine > cloaca (2 regions
which group of animals
esophagus
collects fecal matter from the colon in reptiles
coprodeum
middle part of the cloaca and the ureteric opening in the dorsolateral wall above the papilla of the deferent duct/oviduct opening in reptiles
urodeum
Esophagus > crop > stomach regions (proventriculus > gizzard) > small intestines (2 regions) > large intestine (short) > cloaca
which group of animals
aves
mammals that have specialized alimentary canal because they need to digest cellulose
ruminants
Esophagus > rumen > stomach regions (reticulum > omasum > abomasum) > small intestine > cecum > large intestine > rectum > anus
which group of animals
mammals
lump of food in the mouth that is mechanically broken down by chewing or mastication
bolus
pulpy mass of fluid pushed in intestines which increases in surface area for chemical digestion by enzymes
chyme
wave of contraction produced by encircling muscles of the walls of GIT
peristalsis
Constricts the food in the lumen and forcing it from 1 section of the GI tract to the next
peristalsis
begins at the mouth and ends at the pharynx
oral cavity
have very short oral cavity, while tetrapod’s typically have longer oral cavities
fish
their mouth is specialized to serve as a suckling and masticatory organ (with muscular cheeks)
mammalian mouth
roof of the oral cavity
palate
– internal nares lead into the oral cavity anteriorly
primary palate
nasal passages are located above the secondary palate and open at the oral cavity
secondary palate
air is drawn into buccal cavity from outside and lungs, buccal cavity expands
inspiration
buccal cavity contracts, air is forced out of the nostrils, air is forced into lungs
expiration
derivations of dermal armor
teeth
Vary among vertebrates in number, distribution in the oral cavity, degree of permanence, mode of attachment, and shape
teeth
show gradual transition to teeth at the edge of the jaw
what type of scale
placoid scales
composition of teeth
dentin and enamel
surrounds the dentin in teeth
enamel
include agnathans, sturgeons, some toads, turtles, birds, and baleen whales
toothless vertebrates
teeth are numerous and widely distributed in the oral cavity and pharynx
fishes
teeth widely distributed on the palate
early tetrapods
still have teeth on the vomer, palatine, and pterygoid bones
most amphibians and some reptiles
teeth are limited to the ___ in crocodilians, toothed birds, and mammals
jaws
other than mammals, their teeth are shaped the same (_____ dentition)
homodont
mammalian teeth exhibit morphological variation: incisors, canines, premolars, and molars (_____ dentition)
heterodont
teeth for cutting
incisors
teeth for piercing and tearing
canines
teeth for macerating
premolars and molars
muscular organ in the mouth of most vertebrates that manipulates food for mastication and is used in the act of swallowing
tongue
has importance in the digestive system and is the primary organ of taste in the gustatory system
tongue
tongue is largely immobilized in the floor of the oral cavity and cannot be extended
a. turtles, crocodilians, some birds, and whales
b. snakes, insectivorous lizards, and amphibians, and some birds
c. mammals
A
tongue sometimes long and may move in and out of the oral cavity
a. turtles, crocodilians, some birds, and whales
b. snakes, insectivorous lizards, and amphibians, and some birds
c. mammals
B
tongue is attached to the floor of the oral cavity (via the frenulum) but can still be extended out of the oral cavity
a. turtles, crocodilians, some birds, and whales
b. snakes, insectivorous lizards, and amphibians, and some birds
c. mammals
C
function of vertebrates tongue
➢capturing and gathering food taste
➢Manipulate fluid sand solids in oral cavity
➢Swallowing
➢Thermoregulation
➢Grooming
➢Human speech
secrete a variety of substances including saliva, poison, and anti-coagulant
oral glands
part of the throat behind the mouth and nasal cavity, and above the esophagus and larynx – the tubes going down to the stomach and the lungs
pharynx
Part of the digestive tract exhibiting pharyngeal pouches (at least in the embryo) that may give rise to slits
pharynx
in them, the pharynx is the respiratory organ
fish
in them, the pharynx is part of the foregut proceeding the esophagus and includes
tetrapods
slit leading into the larynx
glottis
in the pharynx, it containts (3)
glottis
opening of auditory
opening into esophagus
in them, an epiglottis is positioned over the glottis so that when this animal swallows, the
larynxis drawn forward against the epiglottis and the epiglottis blocks the glottis (which prevents food or liquids from entering the trachea)
mammals
distensible muscular tube connecting the pharynx and the stomach
esophagus
the esophagus may have diverticulum called the ___ in birds
crop
muscular chambers at the end of the esophagus
stomach
serves as storage and macerating site for ingested solids and secretes digestive enzymes
stomach
vertebrate stomach that is weakly developed; similar to esophagus
cyclostomes
vertebrate stomach that has increasing specialization (more differentiated from the esophagus)
fish, amphibians, and reptiles
proventriculus (glandular stomach) and ventriculus (muscular stomach, or gizzard)
group of animals
birds
they have well-developed stomachs; ruminants have multi-chambered stomachs
mammals
main fermentation vat where billions of microorganisms attack and breakdown the relatively indigestible feed components of the ruminant’s diet
rumen
true stomach and the only site on the digestive tract that produces gastric juices (HCl and the enzymes, pepsin, and rennin)
abomasum
important site for digestion and absorption
intestine
differentiated into varying degrees into small and large intestines
intestine
have relatively short intestine
‘
group of animals
fishes
the intestine of cartilaginous fishes have these
spiral valve
their intestines differentiated into coiled small intestine and short, straight large
intestine
amphibians
coiled small intestine and relatively short large intestine (that empties into the cloca)
reptiles and birds
small intestine long and coiled and differentiated into duodenum, jejunum, and ileum. The large intestine is often relatively long (but not as long as the small intestine)
mammals
present in the junction of small and large intestine in herbivores
cecum
is a process that converts ingested feed into energy sources for the host
rumen fermentation
provides nutrients and energy for the growth and division of the microbial populations participating in this process
fermentation
produces bile which is stored in the gall bladder
liver
cyclostomes, most birds, and some mammals, including cervids (deer)
do they have gall bladder?
no
secretes pancreatic juice into the intestine
pancreas
to neutralize acids coming from the stomach
bicarbonate solution
to help digest carbohydrates, fats, and proteins
enzymes
to help digest carbohydrates, fats, and proteins
ceca
chamber at the end of the digestive tract that receives the intestine, and urinary and genital ducts, and opens to the exterior via the vent
cloaca
shallow or non-existent in lampreys, ray-finned fishes, and mammals (except monotremes)
cloaca
if this is not present, the intestine opens directly to the exterior via the anus
cloaca
pyloric and duodenal ceca are common in these (teleost), these are primary areas for digestion and absorption (not fermentation chambers)
fiashes
ceca are present in some of these; may contain bacteria that aid in the digestion of cellulose
tetrapods
stores food but no digestion in birds
crops
provides chemical digestion (enzymes) in birds
proventriculus
provides mechanical digestion (grinding) in birds
gizzard
provides enzymes for emulsifying fats
livers
provides majority of enzymes for chemical digestion
pancreas
primary location for final digestion and
most absorption
stomach
some digestion of fiber (symbiotic bacteria) in birds
ceca
largest stomach, contains prokaryotes and protist to ferment and digest cellulose fiber (chemical)
rumen
similar to rumen but can contract to regurgitate contents to mouth for further mechanical digestion
reticulum
receives cud from mouth and removes water and absorbs minerals, other functions not well understood
omasum
similar to nonruminant stomach, contains enzymes specifically for protein digestion
abomasum
perform same function in other vertebrates
liver pancreas, small, large intestine
exclusive for feces
anus
do ruminants have cecum?
no
*complete
*begins with mouth end with anus
*entirely extracellular
*digestive enzymes are secreted by the wall of the digestive tract, or by nearby glands and organs
human
secretes acid and digestive enzymes for PROTEINS, churns food
stomach
final breakdown, absorb nutrient molecules into body
small intestine
absorb water and salt
large intestine
secrete saliva; contain digestive enzyme for CARBOHYDRATES
salivary glands
produce bile for emulsification of FATS
liver
store bile from liver; send it to small intestine
gallbladder
contains digestive enzymes, and sends it to the small intestine; produces insulin and secretes to the blood after eating
pancreas
