Final review Flashcards
What is the pituitary gland?
In the sphenoid bone of the skull, anterior has pars distalis (associated with sinusoids, has chromophobes and acidophils-produce growth hormone and prolactin-basophils-TSH/LH/FSH/ACTH/tuberalis (forms a collar)/intermedia (MSH and ACTH), posterior has pars nervosa and infundibular stalk
What is the neurohypophysis?
Pars nervosa and pituitary stalk, has unmyelinated axons and cell bodies in hypothalamus, secretes oxytocin and vasopressin, can see Herring bodies
What is the thyroid gland?
From buccal cavity, have follicles full of colloid made of thyroglobulin, have follicular cells with microvilli and has thyroglobulin (stored in lumen, broken down to produce T4 and active T3 which increases active metabolic rate and increases mitochondria) which is strong antigen, parafollicular cells are isolated clusters of paler cells producing calcitonin; has endocrine and storage functions; calcium sensitivity through CaSR protein
What are the parathyroid glands?
has capsule and parenchyma; chief cells-dark ones produce parathyroid hormone (raise calcium levels) and oxyphil cells are acidophilic
Describe the adrenal glands
Cortex-glomerulosa-produces mineralocorticoids (aldosterone) which is stimulated by angiotensin; fasciculata-glucocorticoids like cortisol stimulated by ACTH; reticularis-weak androgens; medulla-has chromaffin cells which have catecholamines and are stimulated by preganglionic sympathetic fibers
What is the pineal gland?
Photoreceptor is for lower vertebrates, secretes melatonin and serotonin, divided into lobules, has pinealocytes/astrocytes and brain sand
What is the overview of male repro organs?
Testes-produce spermatozoa and testosterone, duct system collects/stores/waits for sperm maturation, seminal vesicles and prostate are exocrine-produce seminal fluid which is nutritious and lubricating, semen has fluid, sperm, and duct lining cells, penis with bulbourethral glands secrete fluid which lubricates urethra for semen passage
Describe the testes
exocrine-produces spermatozoa, endocrine-Leydig for TTT and Sertoli for estrogen production, tnica albuginea has tunica serosa on it, mediastinum testis at anterior pole made of areolar CT and part of rete testis, septula testis divides testes into lobules; seminiferous tubules-has basal lamina and is space for spermatogenesis, myoid cells, Sertoli/nurse cells (tall triangle shape with vesicular nucleus, for support, phagocytosis, androgen binding protein, activin, inhibin, create blood-testis barrier with tight junctions)
What is spermatogenesis?
Divided into three phases: mitosis, meiosis, and metamorphosis; spermatogonia is most primitive and located in the periphery of seminiferous tubules (A=stem cells, upon mitosis one remains A cell (asymmetric division))and the other divides to get I->B cells->primary spermatocytes which are the largest and has 4N DNA with an extended prophase of meiosis for genetic diversity->secondary spermatocytes with 2N DNA and undergo 2nd meiotic division to get->spermatid where nuclei become flattened and heterochromatic and haploid DESCENDANTS OF SPERMATOGONIUM ARE CONNECTED BY CYTOPLASMIC BRIDGES EXCEPT SPERMATOZOA
What are spermatozoa?
Mature formed during metamorphosis stage, development of acrosome (cap with hyaluronidase), flagellum; waves of development occur in s. tubules
What is cryptorchidism?
Retention of at least testicle in the abdominal cavity, in swine and horses it is hereditary, bilateral retention->infertility because sperm are sensitive to temp, should be removed unless FSH/HcG is given pre-puberty
Describe testicular stroma and ducts
Leydig cells-interstitial between s. tubules, acidophilic, produce TTT and controlled by LH; straight tubules-cuboidal epithelium and are connections; rete testis-tubules in mediastinum and secretes fluid, microvilliated; ductuli efferentes-connect rete to epididymis, ciliated simple columnar epithelium; rete and ductuli move non motile sperm to epididymis.
What are the genital ducts?
ductus epididymis: stores sperm while it matures, stereociliated pseudostratified and connects with ductus deferens, takes sperm 13 days to get through epididymis and when they do they are motile and can partially fertilise; ductus deferens: pseudostratified columnar but loses stereocilia, has spermatozoa in mature animals and has a thick muscular layer, peristaltic contractions controlled by sympathetic during ejac
What is a seminal vesicle?
secretes major seminal fluid, which is alkaline to neutralise vaginal acidity, contains proteins/fructose/mucous/flavins/etc.; vesicular glands are found as a cluster, absent in carnivores, has lipofuscin granules in cytoplasm and intranuclear fluid
What are the male accessory organs?
Ampulla-terminal part of vas deferens; prostate-laminated concretions of secretory product found in tubules and aleveoli, produces half of seminal fluid with fibrinolysin (liquefy coagulated semen and disperse sperm in vagina) and citric acid; ejaculatory ducts are short part of d.d. joined with duct of s. vesicles
What is the ovary?
Endocrine gland (produces hormones) and exocrine gland (oocyte) that has a tunica albuginea surrounding the cortex. Hormones are produced by developing follicles, which are transformed after ovulation to corpora lutea. Responds to pituitary hormones like FSH and LH. the cortex has the developing follicles, the tissue between them is stroma, and the mesovarium sits on top of the ovary. The medulla has blood vessels for the ovary and possibly rete ovarii which can form cysts. Primary oocytes becomes arrested in meiosis prophase 1 and when stimulated, form the secondary one and a polar body, formed just prior to ovulation except in dog. After fertilization, the secondary oocyte undergoes 2nd meiotic division and becomes an ovum
What are the oocytes?
Inside follicles, surrounded by zona pellucida (glycoprotein layer secreted by oocyte and granulosa cells) and granulosa cells, a theca outside the follicle
Describe the follicles
Primary-oocyte surrounded by granulosa cells, secondary-follicular fluid shows up between granulosa cells, tertiary-has large fluid filled cavity/antrum with granulosa cells on outside (cumulus oophorus), corona radiata is the layer of cells directly in contact with zona pellucida; interstitial cells from theca interna
Describe the ovarian cycle
Luteal phase: corpus luteum produces progesterone to stimulate endometrium and regresses, influenced by uterine PGF2a which causes decline of CL and oxytocin, granulosa cells proliferate, uterine glands are secreting, LH declines; follicular phase: CL degenerates, follicle starts to mature, estrogen produced by granulosa cells in response to FSH->expression of LH receptors leads to surge which starts ovulation and has primary oocyte complete meiosis and starts CL formation in ovulated follicle; after ovulation a corpus hemorrhagicum forms when blood fills lumen; some animals need copulation for ovulation to occur
What is the uterus?
Endometrium (tunica mucosa and submucosa, has uterne glands), myometrium (tunica muscularis), perimetrium (tunica serosa)
What are ruminant caruncles?
elevated vascular areas with no glands, site of attachment of placenta, combined maternal and fetal structure is placentome
What is the cervix?
Stratified squamous in female dogs, columnar in others, tunica muscularis has inner circular and outer longitudinal layers
What is the vagina and vestibule?
No muscularis mucosa so lamina propria directly joined to submucosa; distal to urethral opening, has glands, part of the vulva
Name the estrus cycle
Proestrus-CL regressing and new follicles are growing, theca cells produce androgens and stimulated by LH, granulosa cells secrete estrogens and are stimulated by FSH; estrus-ovulation occurs and CL grows, estrogen is maximized and granulosum layer is maximally developed, LH secretion increased, leads to heat, most cornified cells; metestrus-where CL develops and progesterone levels increase, NOT IN DOG; diestrus-CL is active and uterus reaches maximal gland secretion of progesterone, pseudopregnancy in dog where CL regression causes increase in prolactin->pyometra; anestrus-period of sexual inactivity
Describe mammary glands
Compound gland, large ducts, corpora amylacea are concretions of secretory material found in alveoli; myoepithelial cells are contractile cells stimulated by oxytocin to milk letdown, smooth muscle and elastic fibers surround ducts, stroma scant during lactation
Define renal lobe
cortex made of pars convoluta and pars radiata, inner medulla made of loops of henle and collecting ducts (open in papilla called area cribosa)->minor calyx and then to major calyx or renal pelvis
Define the functional unit of each kidney
Uriniferous tubule which includes: nephron which produces urine and includes renal corpuscles (glomerulus) and tubules (convoluted tubules and loop of henle, and collecting duct which collects, concentrates and transports urine
What is the renal corpuscle?
Includes glomerulus which connects afferent with efferent arterioles which has the Bowman’s capsule with an inner/visceral layer lined with podocytes (cytoplasmic processes called pedicles which form filtration slits) which cover entire surface of capillary and outer layer, vascular pole where where arterioles enter and leave, urinary pole where proximal tubule originates
What are mesangial cells?
phagocytic cells found between capillaries of glomerulus, processes extend between endothethial cell, clean Glomerular Basement Membrane of particulate matter
What is the filtration barrier?
formed by fenestrated capillary epithelium, GBM (fused basal lamina and podocytes and has three layers, filters by size because of type 4 collagen and by charge due to heparan sulfate), filtration slit between podocytes
What are the functions of the kidneys?
Filtration-water and solutes in the blood leave vascular space and enter lumen; tubular reabsorption where substances move across lumen into interstitium and capillaries (all of glucose is reuptaken in the PCT, most sodium is absorbed there and L of H, urea absorbed in PCT, extent of water absorption influences amount of urea); tubular secretion where substances move from cells into the lumen after uptake (water and urea are passive), parathormone/aldosterone/ADH affects it, exogenous and endogenous compounds secreted
Explain tubular epithelium
Asymmetric distribution of channels and transporters in apical and basement membranes and permeability of zonula occludens for paracellular transport
Describe the PCT
tubules fill most of cortex, longest part of the nephron, specialised in reabsorption and secretion, has mitochrondria, long microvilli
What is the loop of henle?
few mitochrondria, located in medulla, passive reabsorption of Na and Cl; the thick ascending limb has no microvilli and is located in medulla
What is the DCT?
Zone of transition changes to collecting duct epithelium, short microvilli and basolateral folds, more empty lumen, in cortex, reabsorption of electrolytes
What is the collecting duct?
has principal cells which regulate reabsorption of water and electrolytes and regulated secretion of K+ and in medullary rays; has intercalated ducts which are in medullary rays and help maintain acid-base balance
What is the JG apparatus?
Found between vascular pole and returning DCT of same nephron, regulate blood pressure by specialised cells, has macula densa (tall and dark, chemoreceptors), juxtaglomerular cells (smooth muscle, secrete renin), mesangial cells (stimulate JG cells)
What is neuropil?
Background of grey matter with cell processes, unmyelinated. Organized in horns
What do funiculi contain?
Ascending and descending tracts
What are meninges?
Connective tissue layers surrounded by CSF. Dura mater separated from periosteum by epidural space in spinal cord but fused to brain
What is the CNS vasculature?
Specialised blood vessels, surrounded by leptomeninges, , pericytes are responsible for maintaining basement membrane most important adaptation is the tight junctions which forms Blood brain barrier
What is the choroid plexus?
Made of pia mater covered with ependymal cells, make CSF (circulates through central canal, exits via lateral foramina to subarachnoid space, tight junctions between these form blood-CSF brarrier, has fenestrated capillaries
What is the cerebellum?
Provides motor movements, has a molecular zone, purkinje cells provide only efferent route from cortex to deeper cerebellar nuclei, granular layer
Describe the ANS
Visceral part of the nervous system, regulates smooth/cardiac muscle and glands, efferent side is 2 neuron system; sympathetic: Ach NT and then NE; parasympathetic only Ach; enteric: interneurons, sensory neurons, motor neurons; can maintain gut function if vagus and splanchnic nerves cut
Describe the compartments of the brain
Anterior: anterior portion is between cornea and iris, iris has ciliary body, and posterior chamber is between the iris and lens; posterior compartment filled with vitreous humor
Describe the structures of the eye
cornea-avascular and has healing powers, germinal cells at limbus-corneal junction; Bowman’s membrane is basal lamina that support epithelium; stroma-avascular and regulated collagen; descemet’s membrane=BM; endothelium keeps cornea dehydrated; sclera-dense irregular, limbus is germinal cell center for cornea
What does the uvea have?
Ciliary body (covered by 2 layers of retinal origin), iris (extension of choroid, in front of lens, no epithelium in anterior surface, myoepithelial cell in posterior surface, stromal layer has areolar CT, melanin and bv; pupillary sphincter muscle controlled by para.), choroid. Tapetum lucidum between vascular and pigment epithelium; ciliary muscle affects lens thickness and is under parasympathetic innervation, contracting removes tension from zonular fibers which produces a rounder lens for near vision
What is aqueous humor?
resembles plasma in composition but has lactic acid, ascorbic acid and oxygen. drained at filtration angle and then goes to the canal of Schlemm
What is the retina?
Ora serrata is closer to lens, pigmented epithelium has phagocytic ability, dehydrate retina and create immune privilege space of inner eye; layer of rods and cones have membranous vesicles (rods have rhodopsin which is a photoreceptor protein)
What are the layers of the retina
Nuclei of rods and cones->bipolar/horizontal/amacrine->layer of ganglion cells->optic nerve fiber layer with non-myelinated axons; plexiform layers are between these layers
What is the fovea?
Conical depression in the retina, area of least refractory distortion, max photoreceptor sensitivity and greatest visual discrimination, surrounded by macula lutea. no bv
Describe the optic nerve
nonmyelinated afferent fibers from retina converge at optic disk (myelination), and penetrate sclera through lamina cribosa. Blind spot: absence of photoreceptor cells. Retina blood supply from central artery of the retina from ophthalmic
Describe the eyelid
Has meibomian glands-sebaceous glands that secrete oily film that covers tear film to prevent evaporation. 3rd eyelid can be drawn across for protection and moisten eye while keeping visibility. Lacrimal glands have lysozyme, superficial glands of the third eyelid help with that
Explain the parts of the ear
External: pinna with ceruminous glands produce ear wax for protection and lubrication, middle: tympanic membranes transmits vibrations to oval window via ossicles (malleus, incus, stapes) and has tensor tympani muscle which dampens sound of chewing and auditory tube which connects tympanic cavity and pharynx to equalize ear pressure and there are guttural pouches in horses, inner: impulses transmitted to brain for hearing via cochlear nerve and equilibrium due to vestibular nerve, has osseous labyrinth in the petrous temporal bone, inside is membranous labyrinth
What is the osseous labyrinth?
has vestibule (round window for pressure compensation, oval window closed by stapes, utricle which is the dorsal sac which detects horiz. linear acc., and saccule which is the ventral sac that detects vertical linear acc), semicircular canals (rotational acceleration with ampulla that has sensory epithelium), and cochlea. Vibration detected by organ of corti.
What is the membranous labyrinth?
Separated by osseous labyrinth by perilymph but it has endolymph, has simple squamous and neuroepithelium
Where is sensory epithelium?
has hair cells, supporting cells, and gelatinous mass over hair cells. Found in organ of corti (has tectorial membrane over it), cristae (has rotational acceleration and has cupula which is gelatin mass on surface of cells) and maculae (similar to cristae but has otoliths which stimulates receptors)
How is the interior cochlea divided?
scala vestibuli has perilymph, scala media/cochlear duct has endolymph produced by stria vascularis, scala tympani has perilymph and is separated from the previous by basilar membrane
