Histology Flashcards
What are the histological features of the vas deferens?
Pseudostratified columnar epithelium
Lamina propria
Smooth muscle: longitudinal - circular - longitudinal
(circular layer of smooth muscle contracts powerfully during ejaculation)
What are the histological features of the seminal vesicles?
Coiled tubulomuscular glands, develop as outgrowths of vas deferens
Pseudostratified columnar epithelium + basal cells (secrete fructose, proteins, prostaglandins)
Highly folded mucosa (epithelium + lamina propria)
Muscular coat around glandular elements (activated by sympathetic stimulation during ejaculation)
What are the histological features of the prostate?
Epithelium can be cuboidal, columnar, pseudostratified, or simple squamous
Surrounded by fibromuscular capsule (divides gland into lobules)
Secretory elements sit in fibromuscular connective tissue stroma
Divided into zones 1, 2, & 3 (increasing distance from centre)
- 1 = mucosal
- 2 = submucosal
- 3 = mucin glands (tubuloalveolar)
Benign prostatic hypertrophy = zones 1 & 2 (transition zone)
Prostatic carcinoma = zone 3 (peripheral zone)
note: older men have prostatic concretions in the glandular elements (lamellated bodies containing proteins, nucleic acids, cholesterol, calcium phosphate) which can calcify
What are the major cell types and coverings present in the testis?
Seminiferous tubules —> Sertoli cells —> rete testis (anastomosing channel of tubules) —> ductus efferentes —> epididymis —> vas deferens
- Leydig cells found in spaces between seminiferous tubules
- seminiferous tubules surrounded by perilobular connective tissue
- seminiferous tubules divided into lobules by connective tissue strands
- tunica albuginea covers testes (tough connective tissue)
- tunica vasculosa between outer tunica and seminiferous tubules
What are the histological features of the epididymis?
Pseudostratified columnar epithelium + smooth muscle (amount increases with size of tube)
Single, highly coiled tube (~4-6m long) divided into a head, body, and tail.
What are the histological features of the ovary?
Covered in squamous epithelium
- cortex (germ cells in numerous stages of development)
- medulla (nerves, blood vessels, connective tissue, stroma like cells)
- hilum (one pole; nerves and blood vessels enter and leave)
note: all germ cells are derived from yolk sac endoderm
Describe the histology of the ova in embryo.
Primordial follicles = oocyte surrounded by single layer of squamous follicular or granulosa cells
Outline the histological changes to the ova which occur during the menstrual cycle.
Increase in FSH —> granulosa cells become cuboidal and divide —> zona pellucida develops between oocyte & granulosa cells
—> ovarian stromal cells (at outer margin of developing follicle) differentiate into theca folliculi (which develop to secrete steroid hormones) —> fluid-filled spaces appear between granulosa cells (secondary follicle)
—> theca folliculi differentiate into theca interna (secrete oestrogen) & theca externa (vascular connective tissue) —> fluid-filled spaces increase in size, pushing granulosa cells to periphery of developing follicle —> single-fluid filled space forms (antrum) (temporary follicle)
—> oocyte surrounded by granulosa cells (corona radiata) until it is pushed to one side by developing follicle to sit on a peg of granulosa cells (cumulus oophorus) (mature Graafian follicle)
—> cumulus oophorus breaks down —> oocyte and corona radiata float free in fluid
LH surge —> tissue surrounding mature follicle thins and becomes ischaemic —> follicle ruptures and oocyte is released —> corpus luteum forms (blood in centre from ruptured theca externa vessels) —> granulosa cells become granulosa lutein cells (large, vacuolated, pale periphery) which secrete progesterone
Absence of hCG —> corpus luteum degenerates, becomes fibrosed and hyalinated into a white connective tissue (corpus albicans) —> corpus albicans contracts and is resorbed, RBCs removed by macrophages (if process is incomplete, a pigmented structure called corpus nigricans can form)
What are the histological features of the Fallopian tubes?
Wall of Fallopian tube has inner mucosa, muscular layer, and serosal covering
Inner mucosa: columnar epithelium & lamina propria
- ciliated columnar in ampulla
- non-ciliated columnar “peg” cells secrete mucus (increase in number as tube approaches uterus)
- mucus contains nutrients for spermatozoa/oocytes/zygotes & removes glycoproteins from spermatozoa (promotes capacitation = penultimate stage in spermatozoa’ ability to fertilise oocyte)
Muscular layer: 2 layers in ampulla, 3 layers in isthmus
(outer layer is longitudinal, inner layer is circular)
What are the histological features of the uterus?
Supplied by paired uterine arteries, which branch into arcuate arteries, and then straight or spiral arteries
2 layers:
- innermost = endometrium (ciliated simple columnar epithelium + lamina propria containing glands & connective tissue)
- –> stratum basalis (supplied by straight arteries, modified during implantation)
- –> stratum functionalis (supplied by spiral arteries, shed completely during menstruation; new layer develops from cells lining glands in basal layer)
- outer = myometrium (~4 layers of smooth muscle)
How does the histology of the uterus change during the menstrual cycle?
PROLIFERATIVE PHASE (days 5-14) =
- stratum functionalis regenerates from cells lining glands in the stratum basalis
- increased length of endometrial glands (straight, unbranched, tubular)
- stromal cells proliferate and pack between glands
OVULATION & LUTEAL PHASE (days 15-28) =
- glands become coiled (sawtooth appearance)
- stroma becomes oedematous & stromal cells becomes decidual cells (contribute to formation of placenta and secrete prolactin if fertilisation to occur)
- proliferation of WBCs
- endometrial thickening
MENSTRUATION (days 1-4) =
- local prostaglandins cause spiral arteries to spasm, depriving the stratum functionalis of blood
- necrosis and shedding of the stratum functionalis occurs (RBCs & WBCs debris)
- stratum basalis remains (spiral arteries do not spasm)
What are the histological features of the cervix?
Connects uterine cavity and vagina, extending between internal and external orifices (os)
Mostly simple columnar epithelium, changes to non-keratinised stratified squamous epithelium on the inner aspect of the external os
(this point changes during reproductive life; at puberty the junction moves into the cervical canal)
Tall columnar cells with branched glandular cells secrete alkaline mucus
note: Nabothian cysts = blockage of ducts due to infection of endocervical glands (chronic cervicitis) - makes cervix inhospitable to sperm (reduces chance of pregnancy)
What are the histological features of the vagina?
4 layers: epithelium, lamina propria, inner circular muscle, outer longitudinal muscle (adventitia) + oblique muscle in between + underlying mucous glands
Epithelium = non-keratinised stratified squamous epithelium
(accumulates glycogen under influence of oestrogen, substrate for lactobacilli)
Lubricated by cervical mucus and vestibular glands (no glands in vagina submucosa)
Smooth muscle & skeletal muscle present
What are the histological features of the female breast?
Rudimentary at birth in both sexes = lactiferous ducts + areola + nipple
Puberty (female) = oestrogens cause breast enlargement (accumulation of adipose tissue & enlarged ducts)
Ducts have simple cuboidal/columnar epithelia until the level of the lactiferous sinuses, then it changes to stratified squamous epithelium + myoepithelial cells)
Oestrogens induce duct proliferation each cycle (enlarged, tender breasts), progesterone influences development of secretory tissues (appear vacuolated; fat leaks in milk)
Areolar glands/glands of Montgomery are modified sebaceous glands (holocrine secretion) —> can form sebaceous cysts
Lymphatics:
- lateral quadrants = axillary lymph nodes
- medial quadrants = parasternal nodes or to opposite breast (therefore cancer can metastasise to opposite breast)
