Micro 4

Question 0

tunica vaginalis

Answer 0

covering of the testis on the anterolateral surface. extension of the abdominal peritoneum.

Question 1

testis function

Answer 1

produce spermatozoa. (exocrine function) produce steroid hormones (endocrine function)

Question 2

pampiniform venous plexus

Answer 2

surrounds testicular artery. carries blood away from the testicles

Question 3

tunica albuginea

Answer 3

thick capsule of dense irregular connective tissue covering each testis.

Question 4

mediastinum testis

Answer 4

thickening of the tunica albuginea on the posterior surface. vessels and ducts pass through it as they enter or leave the testis. projects inward giving rise to incomplete septa which divide each testis into 250 lobules

Question 5

testicular lobules

Answer 5

1-4 seminiferous tubules per lobule. loose connective tissue stroma (interstitial tissue) containing blood bessels, lymphatics, nerves, and leydig cells.

Question 6

seminiferous tubules

Answer 6

where spermatozoa are produced. each is a long convoluted U shaped loop beginning and ending near the mediastinum. lined with complex stratified germinal epithelium containing well defined basal lamina and spermatogenic cells and sertoli cells. surrounded by a fibrous tunica propria containing myoid cell layers and fibroblasts. myoid cells have contractile properties that help move sperm and testicular fluid through seminiferous tubules

Question 7

spermatogenesis

Answer 7

formation of haploid spermatozoa from the undifferentiated diploid germ cell, the spermatogonium. occurs in an inward direction from the basal lamina toward the lumen. takes 64 days, requires testosterone that is secreted by the leydig cells in the interstitium

Question 8

spermatogonia

Answer 8

begin dividing by mitosis at puberty. type A: continue dividing to produce stem cells or progenitor cells. Type B: progenitor cells that divide into primary spermatocytes. increase number through mitotic cell division. daughter cells remain attached via cytoplasmic bridges (allows for communication).

Question 9

primary spermatocytes

Answer 9

generated by mitotic division of B spermatogonia followed by DNA replication. genetic material is exchanged between paired homologous chromosomes to generate genetic diversity prior to first meiotic division. each produces 4 haploid gamete. Diploid (4N DNA)

Question 10

secondary spermatocytes

Answer 10

haploid (2N DNA). generated by meiotic division of primary spermatocytes. short lived. immediately enter prophase and undergo second meiotic division. sister chromatids separate into two resulting spermatids.

Question 11

spermatids and spermiogenesis

Answer 11

haploid (1N DNA). differentiate into spermatozoa via spermiogenesis. spermiogenesis is the conversion. involves no cell division. occurs while spermatids are physically attached to sertoli cell plasma membrane

Question 12

changes that occur during spermiogenesis

Answer 12

1. acrosome formation: granules accumulate in golgi and coalesce into large vesicle. spreads over anterior half of condensing nucleus to form acrosomal cap containing hydrolytic enzymes to get through zona pellucida of oocyte.
2. flagellum formation: centrioles migrate to form flagellum
3. nuclear changes: nucleus condenses, elongates, and moves anteriorly
4. change in orientation: spermatid turns so head points toward basal lamina and flagellum extends into lumen
5. later changes: excess cytoplasm is released and phagocytosed by sertoli cells. spermatids are released through spermiation

Question 13

structure of spermatozoa

Answer 13

head: flattened and pointed. consists primarily of highly condensed nucleus with acrosomal cap containing enzymes for zona pellucida penetration
midpiece: contains mitochondria wrapped around flagellar axoneme
tail: contains fibrous sheath wrapped around flagellar axoneme

Question 14

sertoli cell function

Answer 14

support, protection and nutrition to developing spermatozoa. phagocytosis of residual bodies shed from spermatids and degenerating spermatogenic cells that failed to differentiate. secretion of testicular fluid into lumen of tubule. secretes androgen binding protein and hormones that regulate release of FSH. blood-testis barrier created by tight junctions

Question 15

leydig cell function

Answer 15

steroid secreting cells that become apparent during puberty. make >95% of the testosterone in males. active for 4 months during gestation then remain quiet until puberyu. stimulated by LH.

Question 16

testosterone

Answer 16

high concentration required for spermatogenesis. androgen binding proteins concentrate testosterone in the seminiferous tubules. acts on sertoli cells to help stimulate spermatogenesis. needed for growth and development of accessory reproductive glands.

Question 17

cryptorchidism

Answer 17

failure of one or both testes to descend into the scrotum. untreated men are sterile with increased risk of testicular cancer. no effect on development of secondary sexual characteristics.

Question 18

staight tubules (tubuli recti)

Answer 18

short tubes within mediastinum that join seminiferous tubules to rete testis. lined with epithelium consisting of only sertoli cells or cuboidal cells.

Question 19

rete testis

Answer 19

network of channels within mediastinum connecting straight tubules to efferent ductules. lined with simple epithelium. produces some testicular fluid.

Question 20

efferent ductules

Answer 20

10-20 ductules connecting rete testis to ductus epididymis. lined with simple epithelium that appears scalloped. 2 cell types: non ciliated cuboidal and ciliated tall columnar cells. the ciliated cells are the only true cilia in the male reproductive system

Question 21

epididymis

Answer 21

crescent shaped structure on superior and posterior surfaces of testis. head, body, tail. spermatozoa enter at head. highly coiled tube with smooth muscle

Question 22

ductus epididymis

Answer 22

highly coiled tube. made up of basal cells and principal (tall columnar cells with stereocilia)

Question 23

functions of ductus epididymis

Answer 23

maturation of newly produced sperm. reabsorption of remaining testicular fluid. phagocytosis of residual bodies and sperm. resevoir for sperm. expulsion of sperm

Question 24

seminal vesicles

Answer 24

secrete pale yellow viscous substance rich in fructose. contributes 70% of the volume of ejaculate.

Question 25

3 zones of prostate

Answer 25

transition zone: site of benign prostatic hyperplasia
central zone: surrounds ejaculatory ducts
peripheral zone: site of most prostate cancers. palpable during digital exam of rectum

Question 26

prostatic concretions

Answer 26

calcified prostatic secretions forming concentric condenstations that are frequently observed in lumen of glands. increase in number with age

Question 27

secretion from prostate

Answer 27

thin milky acidic fluid. rich in citric acid and phosphatase. contains proteolytic enzymes that liquefy the semen. contains serine protease known as prostate specific antigen PSA

Question 28

chronic prostatitis

Answer 28

usually involves bacteria or other infectious agents

Question 29

cowpers glands (bulbourethral glands) secretion

Answer 29

clear alkaline mucus like substance. discharged first during ejaculation to lubricate and neutralize penile urethra

Question 30

glands of littre (periurethral glands)

Answer 30

very small glands located along length of penile urethra. secrete mucous like fluid for lubrication