Male Reproductive System

1. Components:---testis:

produce the male germ cells- gametes(sperm)

produce androgen-testosterone

---gernital ducts: store and conduct the sperm

epididymis

ductus deferens

ejaculatory duct

---accessory gland: their secretion join into semen

seminal vesicle

prostate

bulbourethral gland

penis

2. Testis

1) General structure: ① Capsule:

a. tunica vaginalis: visceral layer-serosa b. tunica albuginea: thick, DCT /mediastinum testis: albuginea became thicker

at posterior aspect /septum: thin septa extend radiately from media

stinum testis to divided the parenchyma into lobule

② Lobule a.    seminiferous tubule: /highly coiled /30-70cm long, 150-250 mm in D /begin as free blind end →run to posterior →

become into straight tubule(tubules rectus) →enter mediastinum testis→rete testis→efferent duct→connect with epididymal duct

b. testicular interstitial tissue: LCT between seminiferous tubule

2) Seminiferous tubule: 30-70cm long, 150-250um in D

---specific stratified epithelium: spermatogenic epi.(seminiferous epi)spermatogenic cellsSertoli or supporting cellmyoid cell: under basal lamina

① Spermatogenic cell:

---5-8 layers

---4 types of cells

a. spermatogonium---outerest layer, one la

yer---structure: /round, ellipsoid cell/12um/round N, deep stained

---classification:

type A:

-dark type A(Ad): ovoid, deep-stained N, stem cell

-Pale type A(Ap): ovoid, pale-stained N, differentiate into type B

type B: round N, chromatin granules are distributed under nucleus membrane, division and differentiate into primary spermatocyte

b. primary spermatocytes ---diploid(2n)cell →duplicate DNA → tetraploid cell(4n) →division ---structure:

round cell, become largest, 18 um, left the basal layerN: large, round, on different stage of division(the prophase of meiotic division up to 22 days)

---through first meiosis divides into two secondary spermatocyte(2n, 23X or 23Y)

c. secondary spermatocyte:

---nearer the lumen

---structure:

round cell, 12um

N: round deep-stained

hard to see- short lived(divide quickly)

---through secondary meiosis divides into two spermatid(1n, 23X or 23Y)

d. spermatid

---structure:

smallest cell, 8um

located at innerest layer

---through spermiogenesis: spermatid become into spermatozoa

e. spermatozoa:---structure of spermatozoa:

60 um lengthhead: -pear-shaped

-flattened -nucleus -acrosome

tail: flagallum (centriole)-neck-middle segment: mitochon

dria sheath-principal segment-end segment

---the processes of spermiogenesis

i. condensation and elongation of N

ii. formation of the acrosome

-cover the anterior and lateral portion of N

-contain hydrolytic enzymes for fertilization

iii. formation of flagellum: for motility

iv. formation of mitochondria sheath

v. discharge of useless organelle and cytoplasm

② Sertoli cell---structure: LM:/columnar or pyramidal cell/rest on basal lamina /extending into lumen/no clear boundary/elongated N: triangular, ovoid, paler-stained, wi

th prominent nucleolus

EM:

/SER(more),

RER(some), Golgi

/mito, lysosome

/MT, MF,

/glycogen, lipid droplet

/tight junction: basal compartment and abluminal compartment

---function: a. support, protect, nourish, regulate and rel

ease germinal cell b. secret androgen-binding protein; bind to a

ndrogen, maintain the level of androgen concentration of lumen

c.  phagocytose degenerated cell and spermiogenic residual bodies

d.  constitute the blood-testis barrier

a.       blood-testis barrier/components:

endotheliumbasal lamina of endotheliumCTbasal lamina of seminiferous tubuletight junction of sertoli cell

/function:protect the seminiferous cells from auto-immune reactionresistant to most harmful factors( radiation, body temperature, infection)

3) interstitial tissue:---LCT---Leydig cell:structure: LM: -in groups -large, polygonal-shaped cell, with round N -acidophilic cytoplasmEM: steroid-hormone secreting cell’featurefunction: secrete testosterone- androgen

4) tubule rectus and rete testis

---tubule rectus: simple cuboidal or low columnar epi.

---rete testis: simple cuboidal epi.