Anatomy quiz 4

Stomedeum

Anterior end of gut tube (becomes mouth)

Proctodeum

Posterior end of gut tube (becomes cloaca)

Gill rakers

Gill pouches blocked off pharynx by ____________

Glottis

Slit-like opening of trachea that closes and is bounded by vocal cords

Epiglottis

Cartilage that covers trachea during swallowing; deflects food down esophagus

Tonsils, thymus gland

Additional pharynx derivatives include

Serosa

Outermost layer of gut tube

Secretes mucous to allow gut to move within coelom

Longitudinal muscle

Deep to serosa

Muscle fibers run length of gut tube

Circular muscle

Deep to longitudinal layer

Muscle fibers run around gut tube

Thicken in some locations and can constrict gut tube = sphincters

Submucosa

Deep to circular layer

Contains glands

Mucosa

Deepest layer of gut tube

Has cells that secrete mucous & digestive enzymes

Villi

Mucosa includes large projections called _____

Microvilli

Villi is covered by smaller projections called _________ (increase surface area for absorption in intestine)

Esophagus

Connects pharynx and stomach

Usually kept collapsed unless food passing through

Becomes longer in tetrapods as neck lengthens

\

Crop

In birds, esophagus develops a posterior sac called the _____, in which food is stored to soften and ferment before digestion

Stomach

holding chamber for food with secondary digestive function

Some vertebrates (e.g. lamprey, carp) lack stomach

Hydrochloric acid = acidic environment; may have first evolved to kill bacteria

Digestive enzyme secretion (pepsin for proteins) evolved later

Lamprey

Lacks stomach

Pylorus

Distal loop of the “J”

Pyloric sphincter

Sphincter that closes off stomach from intestine to chemical and mechanical digestion

Cardiac sphincter

Sphincter at “entry” end of stomach that prevents food and digestive acids from being regurgitated into esophagus

Gizzard

Some fishes and many archosaurs (crocs and birds) have developed a large compartment of the stomach = _________

Characterized by thick walls and holds rocks the animal swallows

Rocks help with mechanical digestion of food

Especially important for birds because they have no teeth to mechanically process food before it gets to the stomach!

Evidence of this in large, plant-eating sauropsid dinosaurs

Ruminants

Have 4-chambered stomachs

Deer, cows

Rumen

First largest chamber of stomach

Reticulum

Second stomach chamber

Omasum

Third stomach chamber

Abomasum

Last stomach chamber

Cellulose

Food largely composed of ________, which vertebrates can't digest

Cud

Food regurgitated as _____ - then re-chewed and swallowed again

Liver

Largest organ in abdomen

Develops as outpocket of gut

Bile

Liver secretes _____

Common bile duct

Bile drained from hepatic ducts into __________________

Only released when food passes into intestine

Gall bladder

In carnivores, _______________ (holding sac for bile) develops off bile duct

Cystic duct

Gall bladder is connected to common bile duct via ______________

Pancreas

Develops as from multiple outpockets of gut

Dorsal lobe develops dorsally from gut

Ventral lobe develops ventrally from liver

Fuse together during development

Secretes amylase, trypsin, peptidases, lipase, and nucleases

Amylase

Starches

Trypsin and peptidases

Proteins

Lipase

Fats

Nucleases

Nucleic acids

Spiral value

____________ in cartilaginous fishes - increases surface area of intestine

Regional differentiation

Tetrapods have ______________________ of the intestine

Stomach empties chyme into small intestine (nutrient absorptions)

Then small intestine leads to large intestine or colon (water absorption)

Duodenum, jejunim, ileum

In mammals sand birds, small intestine further differentiated into three regions:

Cecum

Mammals – diverticulum of intestinal tissue present where small intestine joins large intestine (=________)

Appendix

In some mammals, an ___________ is present at the end of the cecum

Artiodactyls

Foregut fermenters

Perissodactyls

Hindgut fermenters

Hind gut fermenters

Caecum enlarged to form chamber where bacteria break down plant material

Different from ruminants (foregut fermenters)

Coprophagy

Many hindgut fermenters engage in ___________ (ingestion of feces due to high nutrient content)

Embryonically

In mammals, cloaca divides ____________

Rectum

Dorsal portion of cloaca forms _______

diffusion

gas exchange accomplished by __________

bulk

big animals need _____ flow

bulk flow

ability to move large quantities of water or air across thin, moist respiratory membrane

blood vessels

respiratory membrane contains ______________

enable gas (oxygen) to diffuse into blood to be transported through body

muscular pump

bulk flow usually achieved by ______________

ventilation

process called __________

purpose is to make diffusion as fast as possibly

R

rate of diffusion

R=

D \* A \* (delta p / d)

thin, large

membranes should be ____, but have _______ surface area

increase, increase

______ surface area → ________ rate of diffusion

decrease, increase

______ distance → _______ rate of diffusion

ventilation

respiratory: moves air or water = __________

perfusion

circulatory: moves blood = ________

soluble

oxygen is not very ___________ in water

expensive

water is energetically __________ to move

interbranchial

___________ septa: structures between gill slits

gill rays

___________ radiate out laterally from gill arches

lamallae

___________ - structures of the gills

primary

__________ gill lamellae - larger, emerge directly from septum

secondary

__________ gill lamellae - smaller, tightly packed, emerge at right angles from primary lamellae

branchial

water through mouth & spiracle → pharynx → __________ chamber (region of gills)

parabranchial

In branchial chamber, water drawn across secondary lamellae & exits through __________ chambers and external gill slits

Low

blood leaving heart is _____ in oxygen

blood, proximal

______ enters at ________ edge of primary lamella, near septum

distal

water enters at ________ edge of primary lamella

flows to over secondary lamella toward septum

counter-current

________________ exchange system

* allows oxygen to be extracted along entire length of capillary bed
* 80-95% efficiency

suction

_________ pump: contracts coracomandibular and rectus crevices muscles (=coracohyoid and coracoaruals)

force

________ pump: contracts adductor mandible and branchial muscles

ram

variations in fast swimmers:

* leave mouth open all the time
* force water through gills by swimming quickly
* called ______ ventilation
* typically lose or reduce spiracles

spiracles

variations in bottom swimmers

* mouth ventrally located so in dirt on ocean floor
* typically enlarge _________ for ventilation

operculum

bony fished have ___________ - a bony covering over gills

opercular

septa between gills reduced, so primary gill lamellae extend freely into _________ chamber

aseptal gills

single external gill slit is referred to as _____________

sternohyoideus, lavators and dilators

suction pump: contract ________ muscle to expand mouth; then contract _______________________ to expand opercular cavity

adductor mandibulae

force pump: contract ______________________ to close mouth, increase pressure, and force water over gills

labyrinth organs

outpockets off gills that can extract oxygen from air

lungs

most prominent accessory breathing organ; ventral out pocket from gut tube, connect ted to pharynx by glottis

surfactant

internal lung secretion that help prevent chamber walls from sticking together

sternohyoideus

the buccal cavity contracts _______________ to expand cavity and suck air in

glottis

the buccal cavity opens _______ to release air into mouth; releases some spent air but mixes spent and fresh air together

branchial constrictors

the buccal cavity closes mouth and contracts ___________________ to force air into lungs

apnea

breathing is not continuous, but is interspersed with long periods of _______ (periods without breathing)

swim bladder

in most ray finned fishes, lungs transformed into _________________

esophagus

swim bladder grows dorsally from ____________

gas

to prevent collapsing when diving, ______ gland prevents oxygen from leaking out of bladder

rete mirable

_______________ (“miraculous net”)

* sets up counter-current exchange that keeps oxygen in bladder

oval

when oxygen needs released it can diffuse across _____, guarded by sphincter that only releases when necessary

choana, glottis

once reliant on lungs, air passes through mouth or external nares to oval chamber via ______ and from there into lungs via the _______.

transverse abdominis

when glottis opens, fresh air stays on pharynx floor and stale air is forced out lungs by pressure differential and contraction of _________________

cutaneous

____________ gas exchange

* gas exchange directly through skin
* requires moist habitats

plethodontid

____________ salamanders have lost lungs entirely