Exam 3 study guide
Exam 3 study guide Zol 328
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This 20 page Study Guide was uploaded by Kelsey Bowe on Tuesday May 3, 2016. The Study Guide belongs to Zol 328 at Michigan State University taught by Dr. Pam Rasmussen in Spring 2016. Since its upload, it has received 49 views. For similar materials see Comparative Anatomy and Biology of the Vertebrates in Biology at Michigan State University.
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Date Created: 05/03/16
axial skeleton axial skeleton/axis: notochord and vertebral column, supports body, prevent telescoping, sites for muscle attachment -earlist fossil evidenve of vertebrae were in Haikouella and Haikouichthys -ostracoderms primarily supported ny notochord only, as are extant hagfishes -lampreys have neural arches and spines, but lack main parts of vertebrae -it is likely that the vertebral column evolved independently more than once, many parts have been lost and gained throughout evolutionary history • vertebrae components - first components that evolved were the dorsal and ventral arches, resting on notochord dorsal arches= neural and interneural, protect neural tube ventral arches= hemal and interhemal , enclose blood vessels -scond parts of vertebral column to evolve were the two centra, intercentrum/hypocentrum and pleurocentrum, they anchor and support the arches -evetnually, the vertebrae became dominant strucutres and displaced the notochord as the main body axis regions/differentiations of the vertebral column • cervical neck • thoracic chest • lumbar between thorax and hips • sacral hip • caudal tail centrum structure -each centrum makes up the body of a vertebrae • aspondyly: no centrum present • monospondyly: single centrum present • diplospondyly: two centra present • polyspondyly: multiple centra present, Holocephali and Dipnoi can have five or six -may vary by vertebrate type within an individual -can be derived from intercentrum or pleurocentrum -in amniotes, the centra tend to be derived mostly from the pleurocentrum, and intervertebral disks originate from the intercentrum -tetrapods have distinct definitions to describe their vertebral elements: • aspidospondyly: the intercentrum, pleurocentrum, and neural arch all remain as separate ossified elements • holospondyly: vertebral elements fused into a single piece -types of centra • acoelous: flat ends • amphicoelous: concave at both ends • procoelous: anterior end concave, posterior end convex • opisthocoelous: anterior end convex, posterior end concave • heterocoelous: both ends are saddle shaped -apophyses: processes that project from centra and arches, several types: • diapophyses & parapophyses: articulate with ribs • basapophyses: paired processes, ventrolateral on centra, remnant of hemal arch base, may also articulate with ventral ribs • zygapophyses: interlocking processes between vertebrae • transverse process: general term for any process on centrum or neural arch intervertebral structures -intervertebral disk: used to describe many structures, technically only mammals have true intervertebral disks; composed of a pad of fibrocartilage with a gel-like core, this core is derived from the notochord and may also be called the nucleus pulposus, core contains proteoglycans -intervertebral cartilage: only a pad of fibrocartilage -intervertebral ligament: connects edges of centra together ribs -rib: struts that can fuse or articulate with vertebrae, develop as cartilage first within the myosepta provide sites for muscle attachment, protect organs, suspend body types of rib: • true rib articulates with sternum • false rib articulates with a true rib • floating rib has no ventral articulation • bicipital rib rib with 2 heads -capitulum head of bicipital rib that articulates with parapophysis on intercentrum -tuberculum head of bicipital rib that articulates with diapophysis on neural arch sternum -midventral skeletal structure, endochondral, arises from connective tissue and myoseptum -many be a single element or many -is not a deriviative of the ribs or pectoral girdle -not present in fish or early tetrapod fossils, present in modern ampibians and all other tetrapods, may have arisen several times independently rib and sternum structure of different taxa -Fish: most fishes have 2 sets of ribs (dorsal and ventral) dorsal ribs formed where myoseptum and horizontal septum meet ventral ribs form where the myoseptum meets the body wall, homologs of the hemal spine fish lack a sternum -Birds: reduced cervical ribs that are fused to vertebrae, first few ribs of the thoracic region are floating, and the rest are true ribs unicate process: projections found on some bird ribs, extend posteriorly, for muscle attachment birds (neognaths only) have a large keeled sternum, to allow attachment of flight muscles -Mammals: ribs present on all thoracic vertebrae, may some some floating and false ribs pleurapophyses: a remnant of ribs found on cervical and lumbar vertebrae of mammals, fused with the transverse process sternum consists of several elements, as chain of ossified sternebra and cartilagenous elements may have a modified 1ts sternebrae: manubrium and a modified last sternebrae: xiphisternum Gastralia -often called abdominal ribs, gastralia are an independent skeletal element, of dermal origin -located on sides of body wall, do not articulate with the vertebrae -found in crocodilians and tuataras, while remnants of gastralia may contribute to the plastron of turtles -may have evolved from ventral scales of rhipidistians • Embrylogy of Axial Column vertebrate form from embryonic mesenchyme, cells diferentiate after somite formation -Basal Fishes: cells from sclerotomes differentiate into cartilage, up to four pairs of cartlage per segement/arcualia -Teleost fishes: 3 steps of axial development 1 notochord sheath becomes chain of chordal centers middle portions of notochord become intervertebral ligaments 2 mesenchyme condenses to form arch centers/cartilaginous analgen these arch centers give rise to dorsal and ventral arches 3 sclerotome cells condense on surface of notochord, forming an ossified perichordal tube perichordal tube and notochord sheath become the centra of vertebrae -Terapods: 1 somites subdivide into cell layers (dermatome, myotome, sclerotome) 2 mesenchymal cells come from sclerotome and cluster along the notochord form pericardial rings along notochord and eventually become disks other mesenchymal cells connect the rings to form perichordal tube 3neural spines and arches form upward from the neural cord 4 intervertebral bodies or disks define boundaries of each vertebrae 5 ossification of cartilaginous vertebral column cells forming the perichordal tube, cells from the primary and secondary sclerotome become separated and then regroup before forming the complete tube. This allows the the sclerotome and myotome to become staggered as they form the vertebrae and musculature Appendicular Skeleton Skeletal modifications and evolution allowed for the diverse vertebrates we have today Appendicular skeleton: fins or limbs and girdles v Origin of paired fins movement of a streamlined animal -yaw swing from side to side -roll roll over body axis -pitch buck forward or back Fins: membranous or webbed process supported by fin rays (ceratotrichia or lepidotrichia) actinotrichia: keratinized rods in fins Fin Types: -archipterygial fin: metapterygial stem runs down middle of fin -metapterygial fin: metapterygial stem is posterior Theories of fin evolution -gill arch theory (Gegenbaur) : paired fins and girdles arose from gill arches, archipterygial fins arose from gill rays -does not explain pelvic girdle, difference in embroylogy of girdles and gill arches, or presence of dermal bone -fin-fold theory (Balfour and Thacher): paired fins arose from a continuos set of ventrolateral folds in body wall and were stiffened by pte rygiophores, which extended inwards and fused to produce the girdles -supoported by fossil evidence: haikouichthyes and ostracoderms had fin -folds, acanthodians had paired spines v Tetrapod Limbs embryonic development: 1. stylopodium develops 2. stylopodium branches into zeugopodium 3. postaxial unla and fibula branch into autopodium *metapterygial stem elements have evolved into the tertrapod limb supported by Tiktaalik and Icthyostega f ossils v Phylogeny to know -Agnathans ostracoderms lacked pelvic fins, most also lacked pectoral fins -Gnathostomes -Placoderms pectoral girdle made of dermal bones from thoracic armor, braced scapulocoracoid pelvic girdle a single element -Chondrichthyes: early sharks had only one enlarged basal element on each girdle later paired bases of girdles became fused across midline modern sharks have 3 pterygiophores, meta - meso- and propterygium metapterygial stem one long element in pelvic fin -Acanthodians have large spines at leading edge of fins -Actinopterygians parts of pectoral girdle to know: -cleithrum -clavicle -supracleithrum -postcleithrum -posttemporal -scapulocoracoid -Sarcopterygians: Lungfish pectoral girdle has cleithrum, clavicle, and postcleithrum endoskeletal girdle contains scapulocoracoid fins are archipterygial pelvic girdle is one cartilangenous element -Sarcopterygians: Coelacanths pelvic girdle also one element, but more elaborate petoral girdle similar to Neoceratodus(lungfish) -Sarcopterygians: Eusthenopteron (late devonian rhipidistian) fins had bones that are homologues to the stylopodium and zeugopodium of early limbs interclavicle: oval bone, midventrally, overlaps lower tips of pectoral girdle -Tiktaalik earliest fossil where pecto ral girdle is detached from skull loss of supracleithrum and postcleithrum digits but no wrist/ankle bones -Ichthyostega pelvis with 3 bones (ilium, ischium, pubis) attached to vertebral coumn at the ilium defined sacral region hindlimb with 7 digits v Evolution of pectoral and pelvic girdles in tetrapod pectoral girdles, endoskeletal elements become more important than dermal bone pelvic gridle typically has 3 main elements (ilium, ischium, pubis), although they can be fused (birds) -Manus and Pes/Auto podium carpals (forelimb) or tarsals (hindlimb) digits composed of: metapodial, metacarpals/metatarsals, and phalanges pentadactyly: five digits, common among tetrapods but can be different Wrist bones= radiale and ulnare, with intermedium and several centrales in bewteen -Fusions/Losses in forelimb birds only have digits 2,3,4 birds have a neomorph bone in wrists, many other bone fusions in forelimb -fusions/losses in hindlimb cursorial mammals can lose lateral digits cannon bone: enlarged metatarsal III, while other bones have been lost or fused (cursorial mammals) fibulare=calcaneum a tarsal that articulates with the fibula (mammals) tibuiale=astralagus and intermedium (mammals) tarsometatarsus = fused hindlimb (birds) -ankle joints mesotarsal joint: simple hinge btw proximal (astralagus & calcaneum) and distal (metatarsals) elements crurotarsal joint: line of flexion btw calcaneum and astralagus (mammals) *except crocodiles, where the crurotarsal joint is btw the astralagus and fibula v form and function of appendicular skeleton pectoral girdle attached to axial column by muscle softens imact of forelimb, avoids jarring skull pelvic girdle directly attached to axial coulmn secondarily aquatic tetrapods tail usually becomes primary propulsive st ructure whales, plesiosaurs aquatic birds may use wings or feet as primary propulsive structure wings: must be small and stiff (penguins) feet: webbed or lobed toes (ducks) terrestrial locomotion cursorial=running • plantigrade= whole foot touches groun d when running • digitigrade= only digits (toes) touch ground • unguligrade= tips of toes touch ground; usually in form of hooves (enlarged nail/keratin) gives the longest stride length, why ungulates are specialized for running fossorial=burrowing saltorial=hopping aerial=flying arboreal= tree/canopy life brachiation= swinging from branches scansorial= using claws to climb trees gait= sequence of limb movement diagonal sequence= diagonally opposite feet move together lateral sequence= feet on same side move together, more stable *note many tetrapods also use tail as balance and support both gaits invlove rotation of stlyopdium cursorial mammal gaits: • pace= limbs on same side move together • trot= more stable pace • pronk= all four feet strike ground at same time • half bound= back feet in unison, forefeet are not • canter= slow gallop gliding= creating lift and reducing drag found in flying fish, some lizards and frogs, flying squrrels and marsupials, gliding snakes Limb posture ectotherms: typically hve sprawled leg posture, in pectoral girdle force is directed medially endotherms: typically have limbs directly under body, force is upwardly directed more advanced tetrapods, toes rotate forward more From aquatic to terrestrial, there is a shift from lat eral to vertical flexion of axial coulmn powered flight found in only 3 vertebrate groups -birds -pterosaurs -bats Bird flight: -primary feather provide forward thrust, secoondary feathers provide lift, contour feathers streamline body -wing beat cycle upstroke, transistion, downstroke, transition -skeletal movement during flight: in the downstroke, furcula and procoracoids bend laterally, the sternum shifts up and back in the upstroke, furcula springs back, procoracoid becomes more vertical, st ernum drops down and forward -types of flight • hoverers: manus proportionally long (hummungbird) • soarers: need to generate a lot of lift, have long forearms (albatross) • ocean soarers: long narrow wings (shearwater) • thermal soarers: broad slotted wings (haw ks,vultures) • manueverers: elliptical wings for quick takeoff and moving in closed areas (pheasant) • fast flight: narrow swept-back wings (falcons, ducks) -aerodynamics of bird flight 4 forces: upward lift, opposed by weight thrust counters drag wing meets airstream at angle of attack, increasing angle of attack increases lift and drag, 3 -5 degrees below horizontal stalling can happen at extreme angles of attack, prevented by the alula cambered airfoil speeds uo air on upper surface, producing greatest lift possible -origin of bird flight • arboreal hypothesis tree dwelling animals used feathers for parachuting, flailing wings eventually became flying wings • insect-net hypothesis untenable, used feathers as a wide net to capture insects, probably not true • cursorial hypothesis dashing preflight, led to real flight. flapping arms/wings to run uphill = wing assisted incline running Fossorial movement digging occurs in every vertebrate class, many different mechanisms lungfish use body and fins to dig into mud flounders wave fins to move sand to settle under it frogs use hindlimbs, burrow backwards into ground amphisbaenians use head to push through soil moles use head (butressing) and powerful forelimbs (dig ging propulsion) fossorial mammals: limb modifications robust and stout limbs thick claws large muscles elbow lengthened Muscular System Electric Fishes (many taxa - rays, skates, eels, catfish..) electric organs are specialized muscle blocks (branchial or axial) evolved independently in many taxa v Muscle Classification by color red or white by location somatic: moves bone and cartilage visceral: moves organs, ducts, vessels by nervous control voluntary involuntary by histology skeletal, cardiac, smooth by embryonic origin -skeletal muscle multinucleate pattern of fibers, striated appearcne voluntary, rapid contractions - sliding filament mechanism Sarcolemma: muscle cell membrane -Skeletal Muscle: composed of myofibrils each myofibril a chain of sarcomeres, which is composed of myofilaments myofilaments can be thick or thin each muscle cell is inerveated by a branch of a nerve cell -connective tissue wrappings each muscle cell wrapped in endomysium groups of muscle cells wrapped in perimysium entire muscle organ warpped in epimysium -cardiac muscle only found in the heart mononucleate involuntary movement: contraction waves conduct electric impulses through cells and intercalcated disks intercalcated disk: joins cardiac muscle cells together -smooth muscle not striated controls visceral functions (internal organs) slow sustained contractions short, mononucleate, fusiform form into sheets that wrap around organs cells of a sheet are joined electrically and controlled by hormones -tendons connective compartments of muscle organ that attach to bone, two types: aponeuroses: thin, flat sheets of connective tissue fascia: sheets of fibrous connective tissue that wrap around parts and bine them together help to transmit muscle force to ends of bones consume much less energy than muscle cells v Muscle Contraction resting state: no nervous stimulation active state: stimulated by nerves to threshold *in skeletal muscle, myofibrils slide past each other to shorten muscle v Properites of muscle fiber red muscle: higly vascularizd rich in oxygen storage (myoglobin) can undergo sustained contracti on white muscle: low oxygen, less vascularized rapid contraction, not sustained tonic fibers: slow contractions, low force can sustain cantractions for a long time postural support most common in amphibians and reptiles twitch/phasic fibers: rapid movement, fast contractioon can be slow or fast twich slow twich fibers resist fatigue longer (marathon) fast twich fibers are for rapid, unsustained movement (sprint) contractile properties of muscle determined by molecular properties of myofilaments, the proportions of fiber type within the muscle, and patterns of fiber recruitment in muscle activity Variables of muscle performance the force output of a muscle is based on the action (sliding of myof ibrils) + stored elastic tension muscles reach peak force at a particular joint posistion fiber contration is all or none maximum force at thickest part of muscle is proportional to the cross section area of myofibrils so muscles with the same cross sect ion area but different lenghts can have the same force morphological cross section: cross sectional area of a muscle perpendicular to logitudinal axis at thickest part of muscle physiological cross section: cross sectional area of all muscle fibers perpendicular to their logitudinal axes morphological and physiological cross sections are equal only when all fibers are parallel to each other muscle fiber orientation parallel: all fibers run in one direction useful for moving light loads over long distance pinnate: fibers are oblique to line of force, abke to pack in more fibers in a small area useful for moving heavy loads a short distance * most muscle organs are a compromise between these extremes bone-muscle lever systems the ability of a muscle depends on how it is attached to skeleton motion can be rapid: muscle attached close to joint or powerful: muscle attached distal to joint muscle action motor pattern: repetitive movement acitvated by nerve enervation synergists: group of muscles that act together to produce a motion antagonists: muscles that produce opposite actions * one muscle may have many different actions muscle homologies -many muscle fusions/losses/ change in shape as taxa evolved -homologies between taxa can usually be identified if the muscles are enervated by the same nerves, - another way to recognize homolgies is by looking at embryonic development ( ex: shark myotomes develop in the same way as tetrapod limb muscles, so limb mus cles likely evolved from myotomes) -if muscles have similar attachment points in different taxa, they will usually have a similar function, however this does not always inicate homologous structures v embryonic origin of muscles three main sources of muscles: 1- hypomeres (paired section of the mesoderm in an embryo, surrounds gut) forms smooth muscles of digestive tracts 2- mesenchyme (loose group of cells that disperse throughout embryo) smooth muscle from vessel walls and some organs arise from this 3- paraxial mesoderm (somites (trunk) and somitomeres ( head region) that form along body axis and become segemented) develops into most skeletal muscles longitudinal division of myotome becomes epaxial and hypaxial muscles appendicular (limb) muscles originate from ventral tips of myotomes - directly in primitive fishes in teleosts-amniotes: ventral tips of myotomes shed mesenchyme cells that become limb muscles jaw and pharyngeal muscles -hypobranchial muscles: arise from myotomes of trunk somites, sup plied by spinal nerves hypobranchial muscles are found between gills and gill arches, as well as parts of the tongue -branchiomeric muscles: derived from somitomeres in head, supplied by cranial nerves muscles are in walls of pharynx extrinsic eye muscles muscles on the outside of the eyeball that rotate it (six muscles) arise from diferent somitomeres (sometimes called preotic myotomes) inferior oblique superior oblique superior rectus inferior rectus medial rectus lateral rectus branchiomeric (jaw) muscles adductor mandibulae and derivatitves: main muscle for closing jaw in fishes masseter and temporalis jw closing muscles in mammals (derived from adductor mandibulae) Respirtory System cells need continuous supply of oxygen passive diffusion: high pressure to low pressure active diffusion: low pressure to high, gas diffuses through transport systems Gills ventilation unidirectional • internal gills have pharyngeal slits may be covered by protective structures interbranchial septum in chindricthyans operculum in osteichthyans buccal cavity pump moves water across gills • external gills are filamentous capillary beds that project into the water Gas Bladder an elongate air filled sac connected to digestive tract or filled by gas from blood swim bladder: type of gas bladder that controls buoyancy of fish putpocketing of gut or pharynx Lungs ventilation bidirectional elastic bags within body for breathing air develop from outpocketing of pharynx, usually paired Cutaneous (skin) Respiration important in amphibians plethodontid (lungless) salamanders rely completly on this some turtles and snakes use cutaneous respiration usually for over wintering under ice (skin around cloaca highly vascularized) only found in one group of mammals, bats lose CO2 through their wing skin Other Respirtory Organs some catfish gulp air into digestive tract electric eels gulp air into mouth lungfish have well developed lungs Embryoic Respiration chorioallantois: membrane adjacent to eggshell through which an embryo respires through shell pores Mechanisms of respiration air must be moved across respirtory surface to diffuse into blood and other cells cilia provide movement and create more surface area for greater diffusion rates muscular structures are essential for vertebrate respiration 3 main types of respirtory pumps : dual, buccal, aspiration • dual pump: most common in fishes, two pumps - buccal and opercular- working in syncrony to drive water in a continuous flow across gills • buccal pump: air breathing fish and amphibians, mouth cavity expands to fill with air and then compresses to fill lungs • aspiration pump: amniotes, air is sucked into lungs by low pressure includes the lungs, rib cage, and diaphragm Circulatory System Functions: Blood circulation, gas transport, control of activity, stress, pressure, body temp Blood produced by hemopoietic tissues composed of: • plasma: fluid component • red blood cells (erythrocytes): cellular component • white blood cells (leucocytes): cellular component • Platelets: allows blood to form clots • hemoglobin: molecule that transfers oxygen Circulation patterns Single: most fishes, blood passes once through heart in a complete circuit Double: amniotes, blood passes twice through heart in complete circuit Embryonic Development -most vessels arise early in mesodermal mesenchyme as small clumps of cells (blood islands) as these clumps merge, vessels form -The heart forms mostly from splanchnic mesoderm, cells from this area become the epimyocardium- which then differentiates into the myocardium, cardiac muscle, and pericardium -some cells leave the splanchnic mesoderm early in development and form endocardial tubes, which then become the endocardium (lining of the heart) Heart contains four major chambers: • sinus venosus • atrium • ventricle • bulbus cordis Artery System Patterns Anterior: -blood leaves heart from ventral aorta -aorta spearates into aortic arches between pharyngeal slits -aorta divides into external carotoids that supply the ventral head with blood -aortic arches meet paired dorsal aorts above pharyngeal slits -anterior end of dorsal aorta leads into internal carotoids, that supply the head and brain Posterior: -Dorsal aorta supplies rear end of body -subclavian arteries supply anterior appendages -Iliac arteries supply posterior appendages -genital arteries supply gonads -renal arteries supply kidneys -celiac aretery supplies anterior organs -anterior mesenteric artery supplies sm intestine -posterior mesenteric artery supplies lg intestine - portal system connects capillary beds Digestive System Digestive tract = tract and glands associated with processing food, mouth>esopagus>stomach>intestines>cloaca/anus buccal cavity + pharynx+ alimentary canal= digestive tract Main digestive glands: Acessory glands: salivary glands, liver, pancreas Embyronic Devlopment lining of gut is endodermal tissues surrounded by mesordermal mesenchyme tisses from the lateral plate formation controlled by over 100 Hox genes 1- embryonic gut formed from a simple tube of endoderm and is connected to the yolk with a yolk stalk 2- anterior stomodeum meets foregut 3- posterior proctodeum meets hindgut -evolutionary paths can be determined by studying location of hypophyseal pouch and nasal placode, which varies by taxa Buccal Cavity = mouth bounded by oral opening (lips, beak) palatoglossal arch: posterior border of buccal cavity oropharyngeal cavity: mouth + pharynx combined (palatoglossal arch absent) Palate =roof of mouth rhipidistians and tetrapods have internal nares/choanae opening into 1st palate mammals have a fleshy soft palate with the choana more posterior primary palate: includes medial and lateral bone series secondary palate: mammals and crocs, inward growth of lateral bones that form a second roof to cover nasal passages Teeth unique to vertebrate, aid in prey capture, many different types covered in enamel • homodont: all teeth similar in appearance throughout jaw • heterodont: different tooth types • polyphyodont:teeth continuosly replaced • oligophyodont: • diphyodont: 2 sets of teeth troughout lifetime -development of teeth: 1-epidermal enamal organ produces ameloblasts 2-neural crest mesenchyme produces dermal papilla 3-neural crest cells induce ameloblasts to make enamal rodents and rabbit have incisors and cheek teeth that never stop growing elephants have a unique molar system where new tooth rows erupt in rear jaw tooth attachment types • thecodont: teeth set in sockets • acrodont: teeth attached directly to jawbone • pleurodont: attach to the side of jaw heterodont dentition in non mammals: includes specializations for crushing shells, herbivory, venom secretion, and predation mammal teeth: highly differentiated, usually includes incisors, canines, premolars, and molars molariform teeth: premolars and molars • brachydont: low crowns (humans and pigs) • hypsodont: high crowns (horses) • bunodont: cusps form rounded teeth (omnivores) • lophodont: cusps end in straight ridges (rodents, perissodactyls) • selenodont crescent shaped cusps (artiodactyls) cusp types: • protocone • paracone • metacone • hypotone • entotone Tongues first true tongues arise in tetrapods from hypobranchial musculature of hyoid apparatus vomeronasl organ aid in pheramone detection, in most tetrapods, especially predators many specializations: woodpeckers have extremely long tongue and hyoid nectar feeding bird are brush-tipped Pharynx passageway for food and air pharyngeal pouches: form on lateral walls and grow out to meet skin ectoderm inpocketings (branchial grooves) at the partition between these pouches is where gills form in aquatic vertebrates, in mammals these pouches form many structures most vertebrates swallow their food whole and the pharynx stretches *alimentary canal varies significantly between taxa based on the diet of the animal Esophagus connects pharynx and stomach often secretes mucus may be stratified epithelium striated muscle anteriorly that transistions into smooth muscle Stomach expansion of alimentary canal for stirage and processing of food absent in cyclostomes and protochordates folded into rugae when relaxed 3 main divisions: from top to bottom region • cardia, very narrow region, only in mammals, contains cardiac glands that produce mucus • fundus, largest region, fundic glands that produce HCl and enzymes • pylorus, pyloric glands also produce mucus some taxa may have regions of the stomach which are non glandular Intestines mucosa has abundant microvilli on free surface of epithelium microvilli: fingerlike projections on apical surface of cells, increases SA main functions: move food (peristalsis), add secretions, absorb nutrients Sm Intestine villi: multicellular structures that increase surface area regulated by Ileocolic valve into lg intestine Lg Intestine large diameter smooth muscle sphincter controls release of waste products Liver present in all vertebrates produces RBC in fetuses, destroys old ones in adults detoxify blood produces bile metabolic functions very large organ, takes up most of rib cage made of sheets of hepatocytes (bile producing cells) that are divided by blood sinuses Gall Bladder stores bile released into intestine as food passes through it lacking in cyclostomes and some other groups Pancreas 1-2 ducts release pancreatic juice in duodenum juice= mainly trypsinogen, and coverted to trypsin neutralizes stomach acid, protein hydrolysis, carb digestion (amylase), fat digestion (insulin and glucagon) Urogenital Systems =gonads, gametes, hormones, kidneys, bladder, ducts for transport share embryology and some ducts Kidneys dorsal, paired (usually), comoact organs made of millions of tubules functions: filter water to remove waste products from metabolism, produce urine, reabsorb glucose, osmoregulation -development: 1- nephric ridge arises, where nephric tubules will originate 2-nephrotomes appear and differentiate into renal capsule 3- glomerus: capillaries from dorsal aorta grow into renal capsule and clump together 4-nephric duct, nephrocoel, and nephric tubule become the uriniferous tubule pronephros: usually an embryonic renal structure only, connected to coelom with peritoneal funnel mesenephros: adult structure that replaces pronephros, present in adult fish and amphibians metanephros: stimulates growth of metanephric tubules, which compact to form adult kidney organ in amniotes -main functions of kidneys: nitrogen extretion mechanisms: • ammonotelism: direct excretion of ammonia, *water dwelling vertebrates only* because ammonia is toxic but water soluble, may be ecreted through gills, skin, and cloaca • uricotelism: excretion of uric acid, forms a precipitate in cloaca and water diffuses back into blood, reptiles • ureotelism: excretion of urea, concentrated non-toxic fluid, mammals and terrestrial amphibians osmoregulation mechanisms: • hyperosmotic: tissues saltier than water, water enters body • hyposmotic: tissues less salty than water, water leaves body • osmoconformer: blood salt concentration the same as water (hagfish only) Urinary Bladder found in most vertebrates except birds and a few reptiles allows for storage of wastes before excreting Fish: bladder forms at end of urinary duct Tetrapods: bladder is an outpocketing of cloaca Ovaries femal reproductive organ suspened to body wall by mesovarium mesentary ova/egg cells are relased from ovary and travel through ducts for fertilization paired in mosts taxa (exceptions include cyclostomes, some fish, most birds, platypus, some bats and some reptiles) the ovaries may fuse or one may never fully develop Testes paired except in cyclostomes suspended to body wall by mesorchium mesentary produce androgens (hormones)- mainly testosterone and a few others produce sperm Fertilization sperm cell joining with an ova usually external in aquatic animals and internal in terrestial animals often takes place by direct contact of male and female genetalia or intromittent sperm delivery organ salamanders weird exceotion, males drop spermatorphore on ground and female picks up Copulatory Organs (males) sharks/skates/rays/chimeras havce claspers some specialized teleosts have gonopodium tuataras, frogs, birds lack any special organ (except ducks and ratites) squamates have paired hemipenes (only one used at a time) crocs and turtles have single penis usually within cloaca at end of tail all mammals have a single penis, spines are common reproduction is usually seasonal, brought into correct mating condition by hormones
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