--- module: 084-03 language: en chapter: 84 title: "Organ Histology and Structure–Function Recognition" module_title: "Reproductive, skin, sensory, and lymphoid histology with structure–function recognition" source_sha256: 89e8da9880c9021603bbd5f226ad1d8f262455b466a09b1903e03297b14e3255 --- # Reproductive, skin, sensory, and lymphoid histology ## Spatial organisation ### Reproductive tissue varies with age and cycle ### Sensory epithelia transduce stimuli ### Lymphoid compartments organise immune cells ## Testis ### Tunica albuginea, lobules, seminiferous tubules ### Germ cells mature from base to lumen #### Mitosis, meiosis, differentiation ### Sertoli cells span basement membrane to lumen #### Tight junctions form blood–testis barrier #### Inhibin and androgen-binding protein ### Leydig cells secrete testosterone ## Male ducts and glands ### Efferent ductules: scalloped lumen ### Epididymis: stereocilia, sperm maturation ### Ductus deferens: thick three-layered muscle ### Seminal vesicle stores no sperm ### Prostate: corpora amylacea increase with age ### Erectile tissue: endothelial vascular spaces ## Ovary ### Cortex follicles, vascular medulla ### Primordial: one layer of flattened cells ### Primary: cuboidal granulosa, zona pellucida ### Antral: fluid cavity, theca layers ### Corpus luteum makes progesterone #### Without support becomes corpus albicans ### Atresia far exceeds ovulation ## Tube, uterus, cervix, vagina, breast ### Tube: ciliated and peg cells, ampulla folds #### Obstruction: infertility, ectopic implantation ### Basalis regenerates functionalis ### Proliferative: straight mitotic glands ### Secretory: vacuoles, tortuous glands ### Endocervix columnar, ectocervix squamous #### Junction vulnerable to papillomavirus ### Vagina: glycogen-rich, no glands ### Breast proliferates in pregnancy #### Myoepithelial cells aid milk ejection ## Skin ### Strata from basale to corneum #### Corneocytes form the barrier ### Melanin shields nuclei from ultraviolet #### Colour reflects melanosomes, not cell number ### Langerhans cells present antigen ### Papillary loose, reticular dense dermis ### Thick skin lacks hair and sebaceous glands ### Sebaceous glands are holocrine ### Eccrine ducts reabsorb salt ## Eye and ear ### Cornea transparent from orderly collagen #### Endothelium pumps fluid from stroma ##### Cell loss causes oedema, opacity ### Photoreceptors to bipolar to ganglion cells ### Fovea maximises cone resolution ### Optic disc lacks photoreceptors ### Retinal vessels inner, choroid outer ### Inner hair cells transduce sound ### Outer hair cells amplify vibration ### Maculae linear, cristae angular acceleration ## Taste and smell ### Taste receptor cells extend microvilli to pore ### Olfactory axons cross cribriform plate ### Olfactory receptor cells are replaced ## Lymphoid organs ### Lymph node filters lymph #### Cortex: B-cell follicles, germinal centres #### Paracortex: T cells, high endothelial venules #### Medullary cords hold plasma cells ### Spleen filters blood #### White pulp around central arterioles #### Red pulp retains rigid erythrocytes ### Thymus supports T-cell development #### Epithelial reticular cells, Hassall corpuscles #### No follicles or afferent lymphatics ### Tonsils and Peyer patches sample antigen #### Microfold cells transport luminal material ## Recognition by boundaries and routes ### Arrangement shows what is processed