Digestive, Respiratory & Urogenital System of Shark, Turtle & Pigeon

MRD DOGFISH SHARK Body Wall and Pleuroperitoneal Cavity Pleuroperitoneal cavity – large internal cavity; greater part of the coelom Parietal peritoneum – Covers the pleuroperitoneal cavity; smooth shining membrane; adheres closely to the inside of body wall Body wall is composed of skin, muscles & parietal peritoneum Viscera of Pleuroperitoneal Cavity Liver – anterior end of the cavity; large, brownish/grayish Left & right lobe – long Median lobe – small; in which the long, greenish gall bladder is located Esophagus-Stomach – dorsal to the liver on the left side; J-shaped -no external demarcation between the two Esophagus – anterior (papillae) Stomach – posterior (rugae) Pylorus/Pyloric region – constriction of the stomach; sharp bend; decrease in the diameter; extends anteriorly Spleen – dark-colored organ found in the posterior margin of the bend of the stomach (or attached in the duodenum) -Part of the lymphatic system Intestine Duodenum – first part of intestine beyond the pylorus Bile duct – long, stout duct, easily seen descending from the gall bladder to enter the duodenum -runs in a strip of mesentery Pancreas – white gland Ventral lobe of the pancreas – found in the curve of the duodenum Dorsal lobe of the pancreas – long and slender; reaching to the spleen; located dorsal to stomach and duodenum Valvular intestine – part of the small intestine occupied by spiral valve (spiral fold which occupies the interior of the intestine; serves to increase the digestive and absorptive surface of the intestine) Colon/Large intestine – caudal to valvular intestine; narrow Rectal/Digitiform gland – small cylindrical body attached to the colon; which seems to secrete mucus Cloaca – terminal chamber of the colon Anus – opening of the cloaca

MRD Gonads – pair of soft bodies against the dorsal anterior part of the pleuroperitoneal cavity. *In mature females, oviducts are seen as stout white tubes The mesenteries Mesogaster – part of the mesentery supporting the stomach Gastroplenic ligament – portion of mesogaster from the spleen to the stomach Mesentery (limited sense) – portion of the mesentery supporting the small intestine Mesorectum – dorsal mesentery supporting the rectal gland Gastro-hepato-duodenal ligament – remnants of the ventral mesentery; extending from the right side of the stomach to the liver and duodenum; divided into Hepatoduodenal ligament – from liver to the duodenumcontaining bile duct and blood vessels Gastrohepatic ligament – stomach to the liver and duodenum Suspensory/ Falciform ligament – also a remnant of ventral mesentery; found at the anterior end of the liver Mesovarium – mesentery of ovary Mesorchium – mesentery of testis Mesotubarium – mesentery of oviduct (mature females) Transverse septum - partition found at the anterior end of the pleuroperitoneal cavity Coronary ligament - attaches the liver to the septum Abdominal pores – means of communication of the pleuroperitoneal cavity to the exterior; found on each side of the anal opening; purpose is obscure Pericardial Cavity Parietal pericardium – incloses the pericardial cavity Pericardial cavity – where the heart is situated *Heart is attached only at its anterior and posterior ends Visceral pericardium – pericardial lining passing over the surface of the heart as a covering layer Sinus venosus – fan-shaped chamber at the posterior end of the heart Transverse septum – separates the parietal pericardium and parietal peritoneum Oral and pharyngeal cavities and the respiratory system Buccal/oral cavity – anterior; inclosed by jaws and gill arches -bounded in front with upper and lower jaws, provided with teeth Tongue – (primary tongue) at the floor of the mouth; flat, slight, practically immovable projection -supported by the second or hyoid gill arch Pharynx – wall is pierced with 6 internal gill slits Spiracle – 1st internal gill slit; rounded opening in the roof of the pharynx

MRD The remaining five gill slits are elongated Gill pouches – large cavities where the internal gill slits open External gill slits – where the gill pouches open to the exterior Branchial bar/ Visceral arch – tissue between successive gill pouches Interbranchial septum – tissue between gill slits Demibranch – half-gill Holobranch – two demibranchs of both faces Lamellae – respiratory mechanism of the animal in which the blood obtains oxygen and gives up carbon dioxide Female Urogenital System Kidneys – slender, long brown bodies lying against the dorsal body wall, one to each side of the dorsal aorta; RETROPERITONEAL (lies outside of the peritoneum) -mesonephroi/opisthonephoi Anterior portion – thinner; lost its urinary function Posterior portion – thicker; performs the work of excretion Ovaries – pair of soft bodies; oval in form, situated dorsal to the liver -In mature females, ovaries contain eggs, consisting of yolk Mesovarium – ovarian mesentery Oviducts – (immature) slender tubes running along the ventral surface of the kidneys, without mesenteries -(mature) very large tubes; spring free from the kidneys by means of mesotubaria (oviduct mesentery) Ostium – common opening that unites the two oviducts; wide funnel-like aperture lying in the falciform ligament Shell/nidamental gland – slight enlargement in the oviduct (anterior); secretes a thin membrane in which several eggs are inclosed Uterus - posterior enlargement of the oviduct; swings free by means of mesotubarium Cloaca - common chamber for urogenital discharge Coprodaeum – opening of the intestine into the ventral part Urodaeum – slight fold which separates the dorsal urogenital region Urinary papilla/e – located in the middorsal wall of the urodaeum Male Urogenital System Testes – pair of soft bodies dorsally situated; in the anterior part of pleuroperitoneal cavity, dorsal to the liver Mesorchium – mesenty supporting the testes

MRD Kidneys - identical to the female (opisthonephros) Cranial part – lost its urinary function Wolffian ducts – run posteriorly along the dorsal surface of the kidney Efferent ductules -connects the testis to the opisthonephos(kidney); found in the mesorchium Epididymis - part of opisthonephros penetrated by the efferent ductules Leydig’s gland – secrete a fluid beneficial to the sperm Seminal Vesicle – caudal of ductus deferens; wide straight tube Sperm sac – where seminal vesicle terminates; blind sac Cloaca – no dofference in males and females Heart – 2 atria & 1 Ventricle Sinus venosus - posterior and dorsal to the ventricle Conus arteriosus – anterior of the ventricle TURTLE Coelom Parietal peritoneum - covers and conceals the viscera Muscle layer between the skin and peritoneum is lacking in the ventral body wall because of the presence of plastron Ventral body wall consists of: Skin with exoskeleton and peritoneum Pericardial Sac – triangular membranous sac which incloses the heart Parietal pericardium – membranous sac covering the heart Pericardial Cavity – space between pericardial sac and the heart Ventral abdominal veins – run longitudinally in the parietal peritoneum between pericardial sac and pelvic girdle Pleuroperitoneal cavity – walls are lined by the parietal peritoneum Small – pericardial cavity Larger – pleuroperitoneal cavity Pericardial cavity is ventral to Pleuroperitoneal cavity Transverse septum The heart must carry with it the transverse septum and parietal pericardium, in order to move posteriorly, it must separate from the body wall to which it is attached, and so becomes an independent sac called pericardial sac. Pericardial sac lie ventral to the anterior part of the pleuroperitoneal cavity. Viscera and mesenteries

MRD Liver – anterior part of pleuroperitoneal cavity (large and brown; left and right:2) Lateral margins curve dorsally to fit the curves of carapace Transverse septum – membrane between heart and liver; Oblique position Ventral – part of pericardial cavity Dorsal – part of Parietal peritoneum Liver is attached to transverse septum by coronary ligament Stomach – found curving dorsally to the lateral border of the left liver lobe Esophagus – anterior the stomach Gastrohepatic ligament - attaches the stomach to the liver Intestine – posterior to the liver Duodenum – first part and is attached to the right lobe of the liver by the hepatoduodenal ligament Pancreas – white gland situated in the duodenum Gall bladder – large; connected to the duodenum by the bile duct Mesoduodenum – dorsal mesentery supporting the duodenum Fused with hepatoduodenal ligament and appears as one Mesogaster – dorsal mesentery supporting the stomach Distinct from hepatoduodenal ligament Large intestine/Colon Colic caecum – slight projection which is the junction of the small intestine and colon Mesocolon – dorsal mesentery supporting the colon Spleen – dorsal side of colon; rounded red body Urinary bladder - ventral to the colon; large, thin-walled, bilobed Greatly distended with urine Has no ligaments Oviduct – large, white, found on each side of the stalk of the bladder entering the cloaca Mesentery: mesotubarium Ovaries – pair of large sac like bodies containing in their walls eggs of various sizes Mesentery: mesovarium Respiratory system Oral cavity – bounded by the jaws which have no teeth but are clothed with horny beaks of epidermal origin Beaks extend as plates into the mouth cavity

MRD Posterior nares (choanae) – a pair of elongated opening

in the roof of the mouth cavity

Connected with the anterior nares via the passages which runs through the nasal cavities Tongue – floor of the mouth cavity; fleshy and pointed; definitive type 

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Neither gill slits nor gill arches are present but gill arches are represented Laryngeal prominence – elevation behind the base of the tongue Glottis - elongated slit at the center of the laryngeal prominence Arytenoid cartilages – found on each side of glottis Derived from gill arches Auditory/Eustachian tube – a canal or opening posterior to the muscles connecting the skull and lower jaw, leading from the pharynx to the cavity of middle ear. Pharynx posteriorly narrows into the esophagus Trachea/ windpipe - tube stiffened by rings of cartilage Hyoid – found in front of trachea with two pairs of horns Larynx – expanded chamber at the anterior end of the trachea Arytenoid cartilages – found on the lateral walls of the larynx,supporting the two triangular flaps which bound the glottis Cricoid – posterior to the glottis; a ring shaped cartilage 2 Bronchi – where trachea bifurcates which proceeds to the lungs Lungs – large spongy organ; dorsal RETROPERITONEAL - Lung is in contact with the inner surface of the carapace and the parietal peritoneum passes over the ventral surface of the lung, leaving the lung outside the membrane The posterior end of the lung however, projects into the pleuroperitoneal cavity and is clothed with the peritoneum Alveoli - air sacs Bronchus – accompanied by pulmonary artery and vein Pharyngeal cavity - where the path of food and air cross. Path of Air Respiration External nares → nasal cavities → internal nares → oral cavity → pharyngeal cavity → glottis → larynx → trachea → bronchi → lungs

Female Urogenital Sytem Ovaries – large baglike bodies in the posterior part of the pleuroperitoneal cavity – usually contain yellow eggs Mesovarium – mesentery which supports the ovary Oviduct – a large white coiled tube at the posterior border of each ovary Mesotubarium – mesentery that supports the oviduct Ostium – lies in the mesentery and has winglike borders which are generally closed together *The stalk of the large bilobed urinary bladder joins the cloaca midway between the two oviducts Cloaca – common chamber for urogenital discharge Accessory urinary bladder – attached to each side of cloaca posterior to the oviducts -uncertain function; in females, they carry water employed in softening the soil while digging a nest

MRD Clitoris – dark structure in the cloacal wall, homologous in male penis and has no function in females *Opening of the large intestine – most dorsal and is separated by a fold from the urogeniral openings, so that the cloaca is divisible into coprodaeum and urodaeum Ventral to the opening of the intestine are the openings of the oviducts on thickened papillae Kidneys - metanephroi; flattened lobed organs fitting snugly at the posterior end of the pleuroperitoneal cavity -renal portal vein and internal iliac run along the ventral face of the kidney Metanephric duct/Ureter – extending from the middle of the kidney to the cloaca Male Urogenital Syatem Accessory bladders - attached to the lateral walls of the cloaca Penis/Copulatory organ – dark mass seen in the ventral wall of cloaca -inserted into the female cloaca at mating so the sperm are injected directly into the female system Bulbs of the corpora cavernosa – part of the penis; pair of rounded mass that projects from the anterior wall of the cloaca to either side of the stalk of the bladder Testis – yellow spherical body attached to the ventral face of the kidney Mesorchium – mesentery supporting the testis Epididymis – lateral and posterior to the testis; elongated, dark colored coiled body Efferent ductules – connects the testis and epididymis; runs in the mesorchium *Efferent ductules and epididymis are remnants of mesonephros Penis – 2 spongy ridges: corpora cavernosa and cavernous bodies, in between the two is urethral groove. Urethral grooves terminates at the base of a heart shaped projection, the glans of the penis. Ureter – dorsal side of the epididymis; short straight tube proceeding to the cloaca. Heart – 2 atria & 1 ventricle PIGEON Advancement of birds: division of pleuroperitoneal cavity into anterior pleural cavities (lung) and a posterior peritoneal cavity Oral Cavity and the pharynx Oral cavity – anterior Beaks – horny; bounds the roof and floor of oral cavity (incase the jaw); epidermal origin -Teeth are absent Palatal fold – at the roof of the mouth; do not meet on the median line (palatal fissure) -thus called the split palate (imperfect development) Posterior/internal nares – concealed above by the palatal folds Tongue – floor of the oral cavity; compound definitive; not very muscular

MRD Pharnyx Auditory tubes – median aperture at the caudal end of the palatal folds Two auditory tubes unit at one at the point of communication with the pharynx Soft palate – pair of folds which hang down like a curtain at the pharyngeal cavity Lanryngeal prominence – hardened elevation posterior to the caudal end of the tongue Glottis -elongated opening at the center of the laryngeal prominence Laryngeal cartilages – supporting walls of the glottis Hyoid apparatus, Larynx, Trachea, & Esophagus Hyoid apparatus – remnants of the 2nd and 3rd gill arches 3 median elements - entoglossal cartilage (represents 2 fused ceratohyals – anterior horns) Basihyal – posterior to the entoglossal cartilage; median bony piece Basibranchial – posterior to basihyal Posterior horn – ceratobranchial and epibranchial Larynx – expanded chamber at the top of the trachea and opening into the pharyngeal cavity by the glottis *Voice is not produced in the larynx Arytenoid cartilage - on each side of the glottis Cricoid cartilage – enlarge, triangular; ventral side of the larynx Trachea/Windpipe – tube with walls stiffened by rings of cartilage – broad, hard and bony ventrally, but narrower, softer and cartilaginous dorsally Esophagus – dorsal to the trachea; smooth Crop – enormous bilobed sac -where the food which is swallowed whole is detained for a time and may be subject to muscular and enzymatic action; passed to the stomach in small quantities or sometimes regurgitated from the crop and fed to the young Anterior Air sacs and pectoral muscles Respiration: Lungs, air sacs in the viscera & air spaces in bones *Air sacs and air spaces communicate with the lungs by means of the branches of the bronchi -decreases specific gravity and more complete exposure of the lung to the air -air in the lungs is consequently renewed at each inspiration Pectoralis major – great muscle covering the entire sternum and extending to the humerus Pneumatic foramen – entrance to the air spaceof the humerus

MRD *Actions of the pectoralis major and minor are opposed to each other, one depressing, the other one raising the limb. This arrangement eliminates all powerful muscles from the back and enables all of the wing muscles to take their origin from the firm and strong sternum Divisions of the coelom and posterior air sacs Parietal peritoneum – covers the pleural and peritoneal cavity Peritoneal cavity – posterior to the sternum Ventral ligament – mesentery of the gizzard Falciform ligament – extends from the liver to the midventral line of the body wall *Falciform ligament of the liver and ventral ligament of gizzard divides the peritoneal cavity into a large right portion and smaller left portion Pericardial sac – contains the heart Pericardial cavity – space between the pericardial sac and the heart *Only the posterior part of the pericardial sac is freed from the body wall Oblique septum – membranous partition from the points where the pericardial sac meets the lateral body wall; derived from the transverse septum -divides the pleuroperitoneal cavity into 2 pleural cavities(anterior) and a peritoneal cavity(posterior) 

Coelom of birds divided into 4 compartments: Pericardial cavity, 2 pleural cavities, peritoneal cavity

Peritoneal cavity and its contents - lined by parietal peritoneum - at the surface of the viscera (visceral peritoneum) Liver – Right (larger) and left lobe Pericardial sac rests between the 2 lobes Coronary ligament – attaches the liver to the pericardial sac *Absence of gall bladder Gizzard – covered by the left lobe; triturates the food since birds have no teeth and swallows their food whole; horny lining/wall Gastrohepatic ligament – connects the gizzard and the liver Mesogaster – mesentery that connects the gizzard to the dorsal body wall Proventriculus – anterior from the gizzard; contains gastric glands and performs the enzymatic part of stomach digestion; smooth glandular walls Gizzard + Proventriculus = stomach Intestine Duodenum – U shaped loop posterior to the stomach Hepatoduodenal ligament – attaches the beginning of duodenum to the liver

MRD Mesoduodenum – mesentery supporting duodenum Pancreas – lying between the two limbs of the loop Bile ducts (2) – from the right lobe of the liver to the duodenum Pancreatic ducts (3) – pass from the right side of the pancreas into the right duodenum Small intestine – posterior from the duodenum Colic caeca – pair of small lateral diverticula; point of junction of small and large intestine Large intestine/colon – short Cloaca – posterior from the colon; can be traced directly to the anus because of the absence of ischial and pubis symphyses *Absence of urinary bladder; but in the embryo is the presence of allantois Ovary – single left; found in the anterior part of the peritoneal cavity; dorsal to the gizzard Oviduct – single left; entering the left side of the cloaca Spleen – rounded red body; between proventriculus and anterior right duodenum Pleural cavities and their contents Lung – reddish, spongy, flattened organ; dorsal wall of pleural cavity; solid Pleural cavity – cavity where each lung is contained Pleura - passes over the lungs ventral faces, leaving them outside; coelomic membrane Syrinx – expanded chamber where the trachea forks into 2 bronchi; where the voice of birds are being issued *Voice is produced by the vibrations of the pessulus and tympaniform membranes *the bifurcation of the trachea into 2 bronchi can be seen dorsal to the heart Female Urogenital system Single ovary and oviduct on the left side Ovary - a mass containing eggs of various sizes, situated anterior of the left kidney Mesovarium – mesentery of the ovary Oviduct -posterior to the ovary Mesotubarium - mesentery of oviduct Ostium – winglike borders fastened to the mesotubarium Kidneys – metanephroi; flattened 3 lobed organ situated against the dorsal wall Ureters – situated just dorsal to the renal portal veins Left ureter (dorsal) concealed by the oviduct Cloaca – expanded chamber receiving the rectum on its median ventral surface Coprodaeum – large ventral portion; where rectum opens Urodaeum – where oviducts and ureters open

MRD Proctodaeum – most dorsal; opens the anus Bursa of Fabricius – small pouch Male Urogenital system Testes – pair of oval organs at the anterior end of the kidney -lack mesorchia Kidneys – the same as the females Male ducts/deferent ducts – medial surface of the testes -slender, convulated tubes which pass caudad parallel to the ureters Ureters – ventral of the deferent ducts Cloaca -smaller in males and lips of the anus more protruding Heart – 1 atrium & 1 ventricle