histo/embryo after midterm

• covered externally by integument and internally by mucosa
• mucosa - keratinized in ruminants and horses, non in carnivores and pigs
• labial glands - serous or seromucous in propria-submucosa
• tunica muscularis - skeletal muscle fibers of ocbricularis oris muscle
• internal - not always keratinized
• external - always keratinized

• outer - skin
• middle - muscular layer (buccinator muscle)
• internal - mucosa (stratified squamous, maybe keratinized) conical buccal papillae - cattle
• buccal glands are located in the propria-submucosa and maybe serous. mucous, or seromucous

mucosa of cheeks is studded in Ruminants called conical buccal papillae

• rugae- transvers ridges
• stratified squamous keratinized
• proprial-submucosa - dense network of caps, collagen, and reticular fibers
• palatine glands are mucous or seromucous and loacted mainly in the caudal part of the hard palate

• dental pad
• heavily keratinized stratified squamous (thick!)
• dense layer of irregular CT

• dental pad
• buccal papillae
• palatine raphe
• rugae

• stratified squamous
• propria-submucosa containes branched, tubuloacinar, mucous, or seromucous, palatine glands, and lymphatic tissues
• palatine muscles - skeletal muscle fibers oriented longitudinally

• eating, drinking, vocalization
• muscular and mobile
• epithelial specializations
• sensitive and highly innervated
• contains chemoreceptor cites

• muscular organ covered by mucosa
• ventral surface - nonkeratinized
• dorsal surface - keratinized
• mucosa - abundant in caps, arteriovenous anastomoses
• intrinsic lingual muscles - bundles of skeletal muscle (longitudinal, transvers, and perpendicular)
• Lingual glands - seromucosa, scattered between muscle fibers

• dorsal surface of tongue - marcroscopic lingual papillae
• mechanical function - filiform, conical, lenticular
• gustatory function - fungiform, vallate, foliate

• filiform, conical, and lenticular
• facilitate movement of ingesta

• slender, thread like
• keratinized stratified squamous epitheliumhighly vascularized CT corewell developed in cats and ruminants
• horse - fine keratinized threads

• larger than filiform, not as keratinized
• torus linguae - cow
• root of tongue - dog, cat, pig
• pigs - contain a core of lymphatic tissue

• RUMINANTS ONLY
• flattened, lens - shaped projection
• Torus linguae
• covered by a keratinized stratified squamous epithelium
• core of dense irregular CT

• fungiform, vallate, and foliate
• contain taste buds

• mushroom-shaped, covered in non-keratinized, taste buds on upper surface
• taste buds - sparse in horse and cattle
• medium in sheep and pigs
• most in carnivores and goats
• CT core is rich in blood vessels and nerves

• Large and flattened, completely surrounded by epithelium lined sulcus
• extend slightly above the lingual surface and are covered by nonkeratinized
• numerous taste buds in epithelium on the papillary side of the sulcus
• serous gustatory glands deep to the sulcus and dicts open into the sulcus at various level

• parallel folds of lingual mucosa located on the caudo-lateral margin of tongue
• nonkeratinized w/ taste buds on sides of the folds
• absent in ruminants
• rudimentary and w/o tastebuds in cats

• cluster of spindle-shaped epithelial cells that extend from thw basement membrane to a small opening, taste bud pore, at the epithelial surface
• cells - sustentacular(supportive), gustatory(taste receptor), basal cells
• non-myelinated afferent nerve fibers(taste receptors are closely associated with gustatory cells

• lyssa - carnivores
• torus lingue - ruminant
• dorsal lingual cartilage - horse

• RUMINANTS
• cordlike structure
• composed of white adipose tissue
• skeletal muscle
• blood vessels
• nerves
• enclosed by dense irregular CT capsule

• RUMINANTS
• large prominence on the caudal part of the dorsal surface of the tongue

• HORSE
• mid-dorsal fibroelastic cord w/ hyaline cartilage, skeletal muscle and white adipose tissue
• Present inside tongue

• mineralized outer part - enamel, dentine, cementum
• pulp cavity - contains dental pulp, core of connective tissue, blood vessels and nerves

• hardest substance in body
• 99 % in orgainic mineral (hydroxyapatite)
• 1 % organic matter
• produced by ameloblasts
• composed of long slinder rods, enamel prisms, held together by interrod enamel

• 70% minerals, mainly hydroxyapatite, carbonate, magnesium and fluoride
• 30% organic, collagen fibers and glycoprotein
• preoduced by odontoblasts

• like bone
• lamellae oriented parallel to surface, cementoytes in lacuna
• Sharpey's - bundles of collagen fibers, extend from alveoloar bone into cementum of the tooth, fibers form peridontal ligament to anchor tooth to alveolus

• Brachydont
• Hypsodont

• short and cease to grow after eruption is complete
• crown(enamel), neck, and root(cementum)
• thick dentine under cementum

• carnivores
• ruminants - incisors

• longer and continue to grow
• no crown of neck
• cementum and enamel over whole tooth
• enamel on thick layer of dentin
• Infundibulum - enamel invagination

• ruminants - cheek teeth
• horses - permanent teeth
• pigs - canine teeth

• Parotid
• Mandibular
• Sublingual
• Zygomatic (carnivores)

• serous glands
• occasional mucous in dog or cat
• compund acinar - pyramid shaped cells, basal nucleus surrounded by basophilic cytoplasm, apex filled with zymogen granules
• myoepithelial cells between secretory cells and basement membrane

• intercalated duct - lined by low cuboidal epi
• striated duct - simple colmunar w/ striations in basal portion of cell from mito arragned perpendicularly in the deep infolding of basal cell membrane
• Interlobar duct - simple columnar, as ducts get bigger and fuse with other draining ducts changes to stratified columnar

• seromucous
• compund tubuloacinar
• perdominance of mucous acini and serous deliume
• serous demilune - periphery, secrete through intercellular canaliculi
• occasional separate serous units
• similar duct sytem to parotid

• cells filled with mucinogen (mucous precursors) light stain
• nuclei displaced towards the basal part of cells and flattened

• seromucous, compound tubuloacinar gland
• cattle, sheep, pigs - entirely mucous w/ few serous demilune, well developed straited ducts and intercalated ducts
• dog, cat - clusters of serous acini w/ mucous and serous deilunes, not prominent straited and intercalated ducts
• main duct - stratified cuboidal

• long branched
• tubuloacinar secretory units
• predominantly mucous w/ small flattened serous demilune
• no intercalated and striated ducts
• carnivores

• inbetween muscles
• serous and mucous
• keep tongue moist

• Labial
• lingual
• buccal
• palatine
• Molar (cats)

• cats
• similar to zygomatic
• located near commissure of lips and ducts open into oral vestibule opposite to molar teeth

• Tunica mucosa (lumen)- Epi, Lamina propria(loose CT), Lamina muscularis (aka muscularis mucosal)
• Tunica submucosa - CT, glands, vessels, Meisser's plexus(submucosal)
• Tunica muscularis - smooth or skeletal muscles and Auribach's plexus(myenteric)
• Tunica serosa/adventitia (outer most layer)

• stratified squamous
• non - dog
• slight - pig and horse
• keratinized - ruminants
• Lamina propria - dense network of collagen, elastic fibers and loose CT
• Lamina muscularis - longitudinal smooth muscle bundles

• Loose CT w/ vessels and nerves
• seromucous glands -
• dog - whole length
• pig - cranial half of esophagus
• horse, cat and ruminants - pharyngoesohageal junction

• inner circular and outer longitudinal layer of muscle
• cardia (thicker inner circular layer) forms cardiac sphincter
• dog - entirely striated
• cat - skeletal may extend 4/5 of length before change to smooth
• Horses - promient cardiac sphincter, skeletal muscle cranial 2/3, gradually changes to smooth

• Tunica adventitia - cervical region
• tunica serosa - thoracic and abdominal region
• loose CT. vessels and nerves

• has all typical layers
• types -
• simple - horse, pig, carnivores
• compound - ruminants - rumen, reticulum, omasum and glandular abomasum

• absent in carnivoers and small pigs
• horse - separated from glandular region by Margoplicatus
• ruminant - nonglandular region most developed
• stratified squamous and may be keratinized

• 80 % cow is non glandular
• 25-35 % non glandular - horse
• cardiac glands most prominent in pigs

• Mucosa - tongue shaped papillae - core of collagen, recticular and elastic fibers, keratinized, fenestrated caps
• Lamina muscularis - absent
• tunica muscularis - inner circular layer and outer longitudinal layer of smooth m.
• tunica serosa - loose CT, covered by mesothelium, fat, vessels and nerves

• mucosa - reticular folds (honey comb) vertical ridges, conical papillae between folds
• Keratinized
• Propria-submuscularis - collagen and elastic fibers
• laminar muscularis - smooth m pouch in upper part of reticular folds
• tunica muscularis - 2 layers of smooth m. fibers in oblique order and cross at right angles
• tunica serosa - (like rumen)loose CT, covered by mesothelium, fat, vessels and nerves

• extends from cardia to reticulo-omasal orifice
• boredered by 2 thick folds (labia "lips")
• young animal - smooth m layers of the labia contract reflexly during sucking, creates channel to bypass rumen and reticulum

• mucosa - omasal laminae "leaves" studded with macroscopic papillae to help grinde and squeeze food
• keratinized
• lamina propria - dense subepithelia capillar network (no glands)
• lamina muscularis - thick layer beneath the lamina propria on both sides of lamina
• submucosa - thin
• tunica muscularis - thin, longitudinal layer and a thicker inner circular layer of smooth m., innermost layer is continued into the omasal laminae as intermediate muscle sheet

• cardiac, fundic, and pyloris regions
• mucosa - gastric folds (flatten when stomach is filling)
• gastric pits that are continuous with the gastric glands
• gastric glands densely packed w/in the lamina propria
• lamina muscularis is thick
• branched straight tubular
• Ruminant - Abomasum

• pigs - most developed
• glands - short, simple branched,
• coiled tubular to release mucous,
• cuboidal,
• nuclei on basal portion,
• empty into shallow gastric pits

• 4 cells - mucous neck, chief, parietal, endocrine
• Glands - straight, branched tubular that extend into lamina muscularis
• short neck, long body, slightly dilated blind end

• in neck of gland
• mucous cells - flat nucleus towards base of cell
• appear similar to surface cells but have more basophilic cytoplasm

• most numerous
• cuboidal or pyramidal w/ spherical nucleus near base of cell
• basal area lots of RER = basophilic staining
• apical area - vacuoles of zymogen granules which dissolve when fixed as a slide
• secrete pepsinogen - trasformed to pepsin by HCl

• larger and less numerous
• occur singly
• spherical nucleus
• cytoplasm stains w/ eosin and has glandular appearance b/c of numerous mito
• abundance of carbonic anhydrase to help form HCl

• produce GI hormones - gastrin, secretin, cholecystokinin and gastric inhibitory polypsptide
• wedged between basement membrane and chief cells
• products released directly into capillaries
• hard to see

• glands - branched, coild tubular, shorter than gastric glands
• gastric pits with flat nuclei at base of the cell and lightly stain apical cytoplasm
• mucous - flat nuclei at base of cell and stain lightly
• middle - circular layer of tunica muscularis forms pyloric sphincter

• Lamina muscularis - fibers irregularly interwoven smooth m. helps in emptying into glands
• tunica muscularis - loose CT, elastic fibers, vessels and nerves
• tunica muscularis - inner oblique, middle cirular, and outer longitudinal layer (3 layers)
• tunica serosa - loose CT with numerous adipose cells

• Mucosal folds
• Tunical muscularis
• Crypts of Lieberkuhn (intestinal glands)
• Lamina Propria
• Lamina Muscularis
• Tunica Submucosa
• Tunica Muscularis and Serosa

• digestive and absorptive functions
• Mucosal folds - (plicae circulares) in the cranial 2/3
• mucosa - villi
• absorptive surface - microvilli on free surface of simple columnar

• simple columnar w/ numerous goblet cells
• less goblet cells at the tip of the villi
• ileum - greater number of goblet cells
• columnar cells have prominent microvilli to form striated border
• apical cytoplasm - lots of SER(syn of triglycerides)
• golgi coplex (digestive enzymes)
• Basal cytoplasm - lots of RER and free ribosomes (digestive enzymes synthesis)

• base of villi, simple branched tubular invaginations
• low columnar cells - multiply and migrate onto the villus, give rise to columnar and goblet cells
• Paneth cells - at base in ruminants and horses, pyramid shaped w/ acidophilis granules, produce peptidase and lysozyme (antibacteria compound)
• Enteroendocrine cells (argentaffin) - present in intestinal gland

• core of villi and surrounds intestinal glands
• loose CT w/ reticular network, blood vessels, fibroblast, smooth m, plasma cells, and mast cells
• lymphatic nodules - throughout SI, increase in number towards the ileum
• Lacteal - single lymphatic capillary, center of villun, origin of lymph vessel to form a plexus at the base of the villus

• thin and incomplete except on dog (thicker and complete)
• longitudinally oriented smooth muscel fibers derived from lamina muscularis and extend to tip of villi - movement of blood and lymp

• CT denser than lamina propria
• Brunner's gland - tubuloalveolar submucosal glands , mainly in duodenum,
• mucous - dogs and ruminants
• serous - pigs and horses
• mixed - cats
• Peyer's patches - large aggreagted lymphatic nodules, mainly present in the ileum, solitary lymph nodules throughout SI
• vessels and nerves are prominent

• inner circular layer and outer longitudinal smooth m.
• CT between the layers contains myenteric plexus
• thickest in horses
• Serosa - layer of loose CT covered by mesothelium

• Duodenum - brunners glands (submucosa)
• jejunum - crypts of lieberkuhn
• ilieum - peyers patches (submucosa)

• microbial action on the ingesta, absorption(H2O) and secretion of mucous
• no villi or Paneth cells
• longer and less coiled, simlpe tubular glands
• lots of goblet cells
• increase in number of lymphatic nodules
• plicae cirulares are absent
• longitudinal folds
• tunica submucosa - lymphatic nodules

• Cecum - lots of lymphatic nodules
• mucosa - thickes b/c increased length of intestinal glands
• rectum - lots of goblet cells
• pig and horse - outer longitudinal layer of tunica muscularis form flat muscle bands containing numerous elastic fibers called Taenia

• Columnar zone - nonkeratinized, longitudinal folds, tubuloalveolar sweat glands
• Intermediate zone - nonkeratinized, tubuloalveolar sweat glands
• Cutaneus zone - keratinized
• Pigs and carnivores
• carnivores also have anal sacs - bilateral evaginations of ana mucosa, modified sweat glands
• cirumanal glands - mucous

• esophagus - strat squamous
• to
• glandular part of stomach - simple columnar
• to
• anal canal and anus - strat squamous
• as gets closer to outside becomes more keratinized

• covered by CT capsule, dense irregular, divides liver into lobes
• largest gland of body
• high regenerative power
• Kupffer cells - phagocytosis from monocytes

• secret bile - for digestion of fat
• metabolism of protein, carbs, lipid, hemoglobin, and drugs
• hemopoiesis - in fetus
• phagocytosis and detoxification

• serosa covering over thin CT capsule (Glisson's capsule)
• Capsule exteneds into the live as interlobular CT to support parenchyma and form lobules
• interlobular CT - prominent in areas containing branches of hepatic artery, portal vein, bile duct and lymphatics in Portal Area
• pig - distinct interlobular CT septa
• most species - interlobular CT is scant

• Classic - anatomical unit of liver, plates or laminae of hepatocytes radiating from a central vein, hexagonal with portal area between lobules
• Portal - functional unit for bile secretion, triangular, portal area in the center and three central veins of the classic lobules at peripheral angles, direct bile from cental to periphery
• Liver acinus - functional unit for metabolic activity, diamond shaped area made of parts of the 2 classic lobules w/ 2 central veins at the opposing points

• polyhedral and have 3 surfaces
• 1. microvillus surface tha faces the perisinusoidal space
• 2. canalicular surface that borders the bile canaliculi
• 3. contact surface between adjacent hepatocytes where apposed cell membranes may have gap junctions and desmosomes
• centrally placed vesicular nucleus (occasionally binucleate) numerous mito, lyso and ribo, well developed RER and SER, and golgi complexes
• after feeding these cells enlarge and are filled w/ numerous glycogen and lipid inclusions

• bile canaliculus - expanded intercellular space between membranes of adjacent hepatocytes
• cell membranes have short microvilli bordering these spaces
• tigh junctions adjacent to the bile canaliculi prevent bile from excaping into the narrow intercellular space

• smaller interlobular bile ducts
• lined by simple cuboidal
• larger interlobular ducts, hepatic and bile duct - simple columnar epithelium

Bile canaliculi - bile ductules - interlobular bile ducts - hepatic ducts - bile ducts

• Portal vein - blood from intestine
• Hepatic artery - brings oxygen
• interlobar branches of vessels in portal areas
• Hepatic sinusoids - between hepatic laminae, carry blood from the terminal branches of hepatic a. and portal vein to central vein
• lined by endothelial cells and stellate macro(Kupffer cells)
• Perisinusoidal space - separtes endothelium and hepatocytes (villi extend into space for direct exchange of substances between blood and hepatocytes)
• blood from sinusoids - enter central vein and drain to hepatic vein to vena cava

stoned in the gall bladder or in bile ducts

inflammation of bile duct

accumulation of fat globules in hepatocytes

• chronis inflammation with extensive fibrosis
• degeneration and necrosis

inflammation of the liver

• animals w/o - horse (continuous secretion causing greener feces), rat, deer, pigeons
• Function - storage, concentration, acidification, and delivery of bile
• Bile - digest fat by emulsification

• simple columnar
• cattle - goblet cells are present
• propria mucosa - loose CT, lymphatic tissue, (diffuse or nodular)
• tunica muscularis - circularly arranged smooth muscles
• ruminants - serous or mucous glands are present in propria - submucosa

• compund tubuloalveolar gland - produces amylase lipase and trypsin (enzymes)
• similar to parotid salivary gland
• centrocinar cells - in lumen of secretory acinus, secrete bicarbonate (rises pH of intesting contents to help w/ digestive enzymes)
• Intralobar ducts - not striated
• cats - lamellar (Paccinian) corpulscles

• hormones
• islets of langerhans
• lighter areas
• secret insulin

• Oral cavity
• Esohagus
• Crop
• Stomach - proventriculus and ventriculus(gizzard)
• Intestine - Small intestine, 2 ceca
• Cloaca

• beak - cornified (keratinized)
• keratinized
• propria submucosa - diffuse lymphatic tissue (dont have lymph nodes) & salivary glands (branched tubular)
• no teeth
• tongue - keratinized, entoglossal bone

• keratinized
• lamina propria - loose CT, diffuse lymphatic tissue, simple branched tubular mucous glands
• lamina muscularis - longitudinal smooth m.
• tunica submucosa - loose CT
• tunica muscularis - inner circular and outer longitudinal layer of muscles

• sac diverticulum of esophagus
• keratinized
• storage organ - moisten ingested food w/ mucous from esophagus and crop gland
• while brooding - secretes crop milk(desquamated lipid-laden cells)

• glandular
• macroscopic papillae around duct openings of the glands
• columnar cells which continue into glands as cuboidal epithelium
• oxynticopeptic cells - produce pepsin and HCl

• muscular part
• grinding of ingesta
• "koilin" lines and is a secretory product of mucosal glands
• simple comlunar
• mucosal glands - simple branched tubular glands
• lamina propria and submucosa - typical
• tunica muscularis - smooth m. criss-crossed by bands of dense white, fibrous tissue
• sometimes there are ingested stones to help grind
• cuticle - lined, secretory product of mucosal glands

• lamina propria and submucosa - large amounts of diffuse and nodular lymphatic tissue, duodenal submucosa glands are absent
• glands in lamina propria

• at ileocolic junction
• adults - large masses of diffuse and nodular lymphatic tissue infiltrate the lamina propria and submucosa at the cecal orifice "cecal tonsils"
• proximal part of ceca and colon contain villi

• coprodeum, urodeum, proctodeum
• simple columnar
• tunica mucosa - folded extensively, causes compartmentalization of this structure
• lymphatic tissue is associated with CT
• tunica mucosa of vent - highly folded, keratinized, straited muscle forms spincter, no lamina muscularis mucosa
• proctodeum - diverticulum cloacal bursa lymphoid organ

• continuation of digestive system
• Holds feces

• for urin from ureter
• ureteric orifice
• oviduct orific

• nasal cavity, naspopharynx, larynx, trachea and lungs
• air conducting and gas exchange regions

• Gas exchange - most important, acid-base balance
• Cooling - evaporate water loss (important in bird) control of water loss
• Chemoreceptors
• Vocalization

• cutaneous
• respiratory
• olfactory

• nasal vestibule - rostally, keratinized
• mid vestible - non, thinner
• caudal - trasitional zone, stratified cuboidal or nonciliated psuedostratified
• propria submucosa - vessels, nerves, lymphocytes, plasma cells, and macro
• Horse - Nasal Diverticulum, integmuent w/ hairs, sebaceous glands and sweat glands, no function, "false nostril"

• caudal 2/3
• ciliated pseudostratified columnar - 4 types of cells
• propria- submucosa - highly vascular (cavernous stratum), contains serous or mixed nasal glands, numberous nerves and lymph nodules

• ciliated - motile cilia or numerous micorvilli, trap things
• secretory cells - serous or mucous (goblet cells)
• brush cells - thick microvilli associated w/ sensory receptors
• basal cells

• dorsocaudal protion - ethmoidal labyinth
• ciliated pseudostratified columnar epithelium - 3 types of cells
• mixed olfactory glands - in propria-submucosa

• Neurosensory - bipolar cells (neurons) dendrites extend to lumen and axons reach olfactory bulb of brain
• Sustentacular - columnar cells
• Basal Cells

• paired duct - base of nasal septum, opens inot incisive duct
• crescent shape - medial concave and lateral convex mucosa
• Medial - peudostratified columnar has neurosensory, sustentacular and basal cells
• Lateral - pseudostratified columnar has non-ciliated columnar, goblet and basal cells
• propria submucosa - vomeronasal glands (mucous or mixed) and vomernasal cartilage (hyaline) enclosing organ
• detects pheromones

• pseudostratified ciliated columnar w/ goblet cells
• proprial-submucosa - loose CT containing glands
• lymphatic nodules prominent in dorsal portion - pharyngeal tonsil

• non - caudal to voal fold and changes to typical epi
• epiglottis - epi may contain taste buds
• propria-submucosa - dense irregular CT changes to loose CT, elastic fibers, lymphocytes, plasma cells, and mast cells, diffuse lymphatic tissue or solitary lymphatic nodules, mixed glands in caudal portion
• Hyaline - thyroid and cricoid cartilage
• Elastic carilage - arytenoid cartilage

• pseudostratified ciliated columnar w/ goblet
• neuroendocrine cells - at nerve terminals, pyramid shape, abundant in young animals
• migratory cells - lymphocytes, globular leucocytes, and mast cells
• propria- submucosa - loose CT, cubepithelial layer of longitudinal elastic fibers, tubuloacinar seromucous gland
• Hyaline catilage rings - dorsal free ends of cartlage bridged by smooth m. (external-carnivores, internal-other domestic animals)
• external perichondrium - loose Ct, Adventitia

• visceral of pulmonary pleura
• pleura - simple squamous, layer of CT that is continuous with interalveolar septa
• ruminats - thickest, one side can colapse and the other will be fine
• dog and cat - thinnest, both sides of lung will colpase if one side is punctured
• intrapulmonary conducting airways - bronchioles and bronchi
• Gas exchanges area - respiratory bronchioles, alveolar ducts, alveolar sacs and alveoli

• subdivided into primary, lobar and segmental
• pseudostratified w/ goblet, proximodistally, epi height and number of goblet cells decrease, Clara cells increase in number (exocrine glands)
• propria-submucosa - loose C with submucosal glands (decrease distally)
• hyaline cartilage - irregular plates with smooth m. inbetween, proximodistally cartilage decrease, smooth m. increases
• tunica adventitia - loose CT, collagen and elastic fibers

• branch repeatedly then terminate as terminal bronchioles
• simple columnar or cuboidal with cilia and Clara cells (exocrine cells)
• propria submucosa - cartilage and glands (abscent), sparse loose CT, circular smooth m. w/ nerve fibers between muscles
• tunica adventitia - loose CT w/ elastic fibers oriented circularly

• respiratory bronchioles
• alveolar ducts and alveolar sacs
• alveoli

• Transition zone - where mos lung disorders occur
• epithelium is interrupted by alveoli, with smooth m. beneath
• carnivores - respiratory bronchioles are extensive
• horse, cow and pig - short or abscent

• arise from respiratory bronshiole and terminates in clusters of alveoli (alveolar sacs)
• simples cuboidal(upper) or squamous(lower)
• subepithelial CT - smooth m. cells and very few elastic fibers

• Type I - 95%, squamous epi cell with central nucleus, anchored to a continuous basal lamina (pneumocyte - oval nucleus)
• Type II - 5% granular alveolar cell, cuboidal with microvilli that produces pulmonary surfactants (pneumocytes - round nucleus)
• Macrophages - in alveolar lumes, "dust cell" has vaculoes
• interalvolar CT - capillary plexus, fibrocytes, pericytes, lymphocytes and plasma cells, collagen and elastic fibers

• 1. pneumocyte I
• 2. basal lamina of I and of capillary endothelial cells separated by sparse CT, lamina maybe fused
• 3. capillary endothelial cell (simple squamous)
• 4. plasmalemma of red blood cell

• nasal cavity
• trachea
• syrinx
• lungs - primary, hyaline cartilage, secondary, parabronchi (small, dont change volume w/ respiration)
• Air sacs - 8 (no gas exhange)
• Avians - no lymph nodes!!!!!!

• stratified squamous - rostally
• olfactory epi - dorsocaudally
• respiratory epi - lining most of remaining areas

• similar to mammals
• complete circles of cartilaginous rings
• intraepithelial glands are numberous

• junction of trachea and bronchi
• inverted Y shape
• Tympanic membranes- vibrate to produce sounds, stratified sqamous

• pseudostratified ciliated columnar w/ goblet cells and intraepithelial mucous glands
• lamina propria - CT with diffuse and aggregated lymphatci tissue
• lamina muscularis - circularly or spirally oriented mass of muscle with some longitudinal bundles

• in initial portion of bronchi
• replaced by plaques of cartilage

• simple columnar or cuboidal
• no goblet cells, or cartilage
• lamina propria - areolar CT, no lymphatic tissue
• Lamina muscularis - interrupted and multidirectionally oriented

• cuboidal epithelium
• numerous extensions (atria) in lumen give rise to aor capillaries
• atria - lined by simple squamous or cuboidal
• air capillaries - simples squamous, similar to mammal blood capillaries

• most birds have eight
• unpaired cervical
• unpaired clavicular
• paired cranial thoracic
• paired cuadal thoracic
• paired abdominal air sacs
• simple squamous of cuboidal
• no gas exchange
• poor vascularised
• help with flying

• regulation of volume and compostition of body fluid
• filtration of blood
• removal of metabolic wast
• reabsorption of useful metabolites (99%)
• secretion of renin - regulates blood pressure
• production of Hemopoietin (regulate production of RBC)

• embedded in fat, CT capsule and may have smooth m
• parenchyma - outer cotex, inner medulla
• Multilobar or Multipyramidal - bovine(external lobules, 20-22) and pig(internal lobules)
• Unilobar or unipyramidal - cat, dog, horses, sheep, goat
• Hilus- blood vessels, nerves and ureter pass

• renal corpulscles: glomerulus and glomerular capsule (Bowmans)
• Proximal convoluted tubules
• Proximal straight tubule
• thin tubule: descending and ascending parts
• distal straight tubules
• distal convoluted tubules

• arched collecting duct(collecting tubules)
• collecting duct (striaght collecting tubules)
• 1. cortical collecting duct
• 2. medullary collecting duct
• 3. papillary duct
• nephron +collecting duct system = uriniferus tubule (renal tubule)

• Glomerulus + Glomerular (Bowman's) capsule
• vascular pole - arterioles (afferent or efferent)
• urinary pole - proximal convoluted tubule begins

• loops of branching and anastomosing caps (porous endotheilia cells) that connect to afferent and efferent arterioles
• between caps - mesengial or intercapillary cells, stellate cells synthesized from extracellular matrix to support cap walls (similar to pericytes)
• basement membrane(basal lamina) - separates endothelial cells of glomerular cap(filtration) from mesengial cells

• parietal layer and visceral layer, urinary space between
• Parietal layer - simple squamous over thick basal lamina
• visceral layer - caps of glomerulus and made from podocytes
• basement membrane - separates endothelial cells of glomerular cap and podocytes

• primary process that give rise to secondary processes (pedicles) embrace caps of glomerulus
• pedicles interdigitate with adjacent pedicles - Filtration slit between pedicles
• filtrattion silte - bridged by thin electron dense layer called Slit diaphragm

• glomerular endothelium (has pores) porous capillaries
• Glomerular basement membrane
• Glomerular epithelium (visceral layer of Bowman's capsule) w/ podocytes
• 2nd podocytes - space between, pre-urinary fillrate out

• simple cuboidal or columnar cells- acidophilic cytoplasm
• apex of cell - microvilli to form brush border
• Basal straitions - infolding of membrane and alignment of mito
• proximal convoluted - continue into proximal straight (descending thick thimb) brush border less distinct
• Larger and more than DCT, see more in cross section
• lumen is basophilic

• form thin descending limb and thin ascending limb of the loop of Henle
• simple squamous
• nuclei flattened and protrude into the lumen

• shorter, fewer profiles are seen in cortex
• simple cuboidal
• lumen is larger in distal tubules
• small flat cells
• no brush border
• clear lumen

• renal corpuscle
• PCT
• DCT
• collecting tubule
• coritcal colecting duct

• thin tubule
• medullary collecting duct
• proximal and distal staight duct

• renal corpusle
• PCT
• P straight
• think segment
• Distal straight
• DCT
• arched collecting duct
• collecting tubule
• cortical collecting duct
• medullary collecting duct
• papillary duct

• formed between afferent arteriole and distal tubule
• macula dense
• juxtaglomerular cells
• extraglomerular mesangial cells

• distal tubule establishes contact with the vascular pole of the renal corpuscles, modified sement called macula dense
• columnar and nuclei are closely packed
• cells- sensitive to chloride ion content of the tubular fluid, producing molecular signals that promote the constriction of the glomerular afferent arteriole, allows to regulate glomerular filtration

• adjacent to macula densa, smooth muscel cells of tunica media of afferent arteriole are modified - JG cells
• ellipsoid nuclei and cytoplasm is full of secretory granules
• stimulated by reduced blood pressure to produce renin
• renin - angiotensiongen (plasma protein) - angiotensin I - angiotensin - angiotensin II (converting enzyme contained primarily in the lungs)
• Angiotensin II causes vasoconstriction of arterioles and raises blood pressure

• between macula densa and arterioles
• continuous w/ mesangial cells of glomerulus
• unknown function

• arched collecting duct - connects DCT to collecting duct, simple cuboidal
• smaller collectig duct - simple cuboidal, straight lateral cell membrane
• larger collecting ducts - simple columnar
• papillary ducts - 2 layered and becomes transitional towards opening, open into renal crest
• collecting ducts - major component of urine-concentration mechanism

• renal artery - interlobar arteries - arcuate arteries - interlobular arteries
• filter 1 L takes 100 L of filtrate

afferent arteriole - glomerulus - efferent arteriole - descending vasa recta - peritubular capillary network - ascending vasa recta (venules)

interlobular vein - arcuate vein - interlobular vein - renal vein

• close to hilus
• between renal tubules and blood vessels
• cortex - spares
• medulla - plentiful
• collagen fibrils and some fibroblasts
• interstitial cells - lipid laden, prominent in medulla, unknown function

• 1. calyces and reanl pevlis
• 2. ureter
• 3. urinary bladder
• all 3 transtitional

• transittional
• loose CT
• horse - mucous glands (simple branched tubuloalveolar glands) under epith, produce mucous in equine urine

• mucosa - folded, transitional
• lamina muscularis - absent
• horse : propria submucosa - tubuloalveolar mucous glands
• tunica muscularis - 3 ill defined layers, inner and outer longitudinal and a middle circular
• tunica adventitia or serosa - loose CT w/ vessels and nerves

• horse, pig, cow, dog - lamina muscularis is present
• cat - no lamina muscularis
• tunica muscularis - smooth m. called detrusor muscles, irregular shaped interweaving bundles
• can disten 50 to 100 times when full

• Kidney - extende cranially up to lung and caudally at end of synsacum,
• divided cranial middle and caudal
• divided outer cortex and inner medulla
• nephrons - 2 types, cortical (forms majority, is devoid of a medullary loop, henle), confined to cortical region of lobule
• medullary type, penetrates the medullary region of lobules

• testes(produce spermatozoa and hormones
• epididymis(transport and maturation of spermatozoa)
• ductus deferens(transport of spermatozoa)
• accessory sex glands (produce seminal plasma)
• - ampulla of ductus deferens
• - vesicular gland
• - prostate
• - bulbourethral gland
• urethra
• penis and prepuce

• tunica albuginea - predominantly collagen fibers, few elastic fibers and smooth m.
• - interior surface has vasuclar layer formed by branches of testicular arteries and veins
• visceral layer of tunica vaginalis - associated with tunica albuginea

• connective tissue trabeculae from tunica albuginea
• divides testicular parenchyma into varying number of testicular lobules
• lobules - contain 4 seminiferous tubules
• continuous with mediastinum testis - CT that contains rete testis and blood vessels
• Mediastinum testis - well developed in ruminants, pigs and dogs,
• - poorly developed in horses

• convoluted portion (tubuli contorti) and straight protion (tubuli recti)
• 1. lamina propria
• 2. sustentacular or sertoli cell
• 3. spermatogenic cells
• CT between tubules

• surrounds seminiferous tubules
• basal lamina - inner most layer, collagen and elastic fibers surrounded by flat peritubular cells (tubular contraction)
• outer most layer - fibrocytes and collagen fibrils
• basal lamina + peritubular (myloid) cells + fibroblast

• only see nucleus and sperm attached
• elongated pyramidal cells - base adheres to the basal lamina and apex extends into lumen of seminiferous tubules
• numerous processes that surrounds spermatogenic cells
• abundant smooth ER
• well developed golgi
• numberous mito and lysosomes
• oval nucleus at basal protion
• adjacent sustenatacular cells are joined by tight junction and make blood testis barrier

• spermatogenic cells - nutrition, protection, supportive function
• blood testis barrier
• secretion of intratubular fluid - sperm transport
• production of mullerian inhibitory hormone
• phagocytosis of degenerating spermatogenic cells and detached residual bodies of spermatids

• located between and abover the sustentacular cells
• represent carious stages of spermatogensis - spermatogonia, primary and secondary spermatocytes, spermatid and spermatozoa

• next to basal lamina
• small cell
• nucleus contains pale -staining chromatin

• largest cells
• obvious condensed chromosomes (visible)

• short lived
• difficult to observe
• imtermediate in size between primary and spermatid

• small
• located towards lumen of seminiferous tubules
• undergo spermiogenesis and form spermatozoa

• transformation the heads become more deeply embedded in Sertoli cells
• later forced into lumen

• spaces between seminiferous tubules - CT, nerves and vessels (lots)
• Leydig - become apparent after pubert
• rounded or polygonal in shape
• central nucleus
• eosinophilic cytoplasm
• rich in lipid droplets
• testosterone - endocrine, steroid secretion, causes secondary male sexual characteristics

• Staight tubules
• Rete testis
• Ductuli efferentes

• connect the convoluted tubules to rete testis
• simple squamous to simple columnar
• supported by dense connective tissue sheath

• highly anastomotic network of channels
• loose CT of mediastinum of testis
• simple squamous to simple columnar
• produces testicular fluid
• continuous withe seminiferous tubules

• (8-25)
• connect rete testis to ducuts epididymis
• simple columnar ciliated - move spermatozoa
• simple columnar nonciliated - absorb tubular fluid

• surrounded by tnica albuginea
• divided into head, body and tail
• ductus epididymis - long coiled, pseudostraified, loose CT , circular smooth m fibers
• columnar cells - taller in head region, steriocilia - long, branched, thick, microvilli
• basal cells
• function - transport, maturation (head and body) and storage(tail) of spermatozoa

• mucosa - pseudostratified columnar, simple columnar towards end of duct
• propria submucosa - lose CT, rich in elastic fiber and highly vascular
• -terminal part - ampullated (except in pig and cat) contains simple branched tubulo-alveolar glands (simple columnar with secretory activity)
• tunica muscularis - intermingled circular, longitudinal and oblique layers (3 layers)
• tunica serosa/adventitis - loose CT

• seminiferous tubules(tubuli contorti)
• straight tubules (recti)
• rete testis
• efferent ducts
• ductus epidiymis
• ductus deferens

• ampulla - ducuts deferens
• vesicular gland paired - absent in carnivores
• prostate gland - body or compact portion (absent in small ruminants), pars disseminata (absent in horse)
• bulbourethral gland paired - absent in dog

• tubuloalveolar gland
• pseudostratified columnar
• intralobular and main secretory ducts - simple cuboidal
• propria submucosa - loose CT , highly vascularized and continuous with dense CT trabeculae that subdivides the organ into lobes or lobules
• tunica muscularis - varying width followed by tunica serosa/adventitia
• horse - true vesicles, wide central lumen
• bull - compact lobulated organ

• compund tubuloalveolar gland
• compact part - (body) surrounds pelvic urethra,
• disseminate part - in propria submucosa of pelvic urethra, surrounded by striated urethral muscle
• both parts surrounded by capsule of dense irregular CT
• secretory tubules, alveoli and intraglandular duct are lined by simple cuboidal or columnar, change to transitional at terminarl portion of duct
• often - concentrically laminated concentrations of secretoy material ar found in the tubules and alveoli

• compund tubular or tubuloalveolar gland
• fibroelastic capsule containing varying amount of striated muscel cells
• secretory protion is lined by simple tall columnar and show mucin reaction
• collecting ducts - simple cuboidal w/ dark cytopasm
• large intraglandular duct - pseudostratified columnar, changes to transitional at opening

• ampulla
• prostate body
• prostate pars

• prostate body
• prostate pars
• bulbourethral gland

• vesicular
• prostate body
• prostate pars
• bulbourethral gland

• ampulla
• vesicular
• prostate pars
• bulbourethral gland

• ALL
• ampulla
• vesicaular
• prostate body
• prostate pars
• bulbourethral gland

• ampulla
• vesicular
• prostate body
• bulbourethral gland

• pelvis and penile urethra
• folded muscosa - transitional
• propria submucosa - erectile tissue, endothelium-lined caverns of various sizes(vascular stratum) in pelvic urethra
• penile urethra - larger cavernous spaces (corpus spongiosum)
• tunica muscularis - smooth m by bladder, striated m. in remainder of urethra
• tunica adventitia - loose CT or dense irregular CT

• Corpora cavernosa - erectile tissue, endothelium lined caverns, CT and smooth m. surrounded by tunica albuginea and divided by median septum
• Corpora Spongiosum - surrounds penile urethra and also composed of erectile tisse
• Glans penis - well developed in horse and dog, contains erectile tissue, and highley vascularized areolar tissue, stratified squamous, rich in special nerve endings

• testis - very thin tunica albunginea, septa and lobulation are absent, no mediastimum
• epididymis - smaller and less conspicuous than mammals, numerous efferent ducutles, lined by ciliated psedostratified columnar epith, extend along whole length of epididymis, cant distinguish head or body

• no homologous accessory sex glands as in mammals
• some birds at caudal end of ductus deferens forms a mass of convolution called seminal glomus - storage of sperm

• homologus with penis in mammals
• domestic fowl - mounted on crest of ventral lip of vent
• median phallic body - (about 1.5 -3.5 mm) and a pair of lateral phallic bodies which are about 2x4 mm
• ejaculation - protrusion of phallus occur and semen is discharged from papillae of ducuts deferens into median groove and at same time the ventral tip of phallus is applied to the protruded vent of the female