Male Reproduction

Question 1

Male repro components and function

Answer 1

Consists of testes, ducts, genital glands, penis

Functions:

Production of spermatozoa by spermatogenesis
Production of androgens (male sex hormones)
Deposition of spermatozoa into female reproductive tract

Question 2

3 layers of the testes

Answer 2

Surrounded by testicular capsule:

Outer Layer = Tunica vaginalis - mesothelial lining

Middle Layer = Tunica albuginea - fibroelastic CT with smooth muscle cells

Inner Layer = Tunica vasculosa - highly vascular areolar CT

Question 3

Why are the testis outside the body

Answer 3

Situated external to abdominal cavity in scrotal sac
Allows reduced temperature (about 2oC) below that of the body core (37oC), this reduced temperature is important for viability of sperm

Question 4

Where are spermatozoa produced?

Answer 4

seminiferous tubules

Question 5

seminiferous tubules

Answer 5

highly convoluted tubules grouped by septal extensions of capsule into lobules (contain up to 4 seminiferous tubules per lobule)

Question 6

What are the seminiferous tubules lined by

Answer 6

highly modified stratified cuboidal epithelium, underlain by basal lamina and peritubular CT

Question 7

Myoid cells

Answer 7

(contractile) in peritubular CT assist in movement of sperm along tubule

of seminiferous tubules btw

Question 8

Two cell types in the germinal epithelium in the testis

Answer 8

Spermatogenic Cells

Sertoli Cells

Question 9

sertoli cells

Answer 9

= nutritive and supportive cells; extend from base to lumen; nucleus with prominent nucleolus which distinguishes it from germ cells

Question 10

spermatogenic cell order of maturation as you get further from the basal lamina

Answer 10

: in sequence from basal to lumenal surface = spermatogonia (2N), Primary Spermatocyte (2 X 2N), Secondary Spermatocyte (2 X 1N), Spermatid (1N), Spermatozoa (1N)

Question 11

3 types of spermatogonia present in the testis

Answer 11

pale type A
dark type A
type B

all located on the base of the seminiferous tubules

Question 12

pale type A spermatogonia

Answer 12

stem cells (renewing cells); ovoid lightly stained nucleus

Question 13

dark type A spermatogonia

Answer 13

reserve stem cells; divide infrequently and only if renewing stem cells become depleted; ovoid darkly staining nucleus

Question 14

type B spermatogonia

Answer 14

differentiating progenitor cells – beginning process of spermatogenesis; spherical nucleus with densely stained masses of chromatin

Question 15

Spermatozoa: 3 regions

Answer 15

head
midpiece
tail

Question 16

Spermatozoa head

Answer 16

contains 1N nucleus and is crowned by acrosomal cap = contains hydrolytic enzymes for penetrating egg surface

Question 17

spermatozoa midpiece

Answer 17

forms base of tail and is surrounded by a small amount of cytoplasm that is rich in mitochondria (mitochondrial sheath), provides energy for swimming

Question 18

spermatozoa tail

Answer 18

flagellum, allows motility

Question 19

Describe the cell found in the interstitial tissue of the testis and its function

Answer 19

Between seminiferous tubules is areolar CT (interstitial tissue) containing Leydig Cells = large polyhedral or ovoid cells, contain pale acidophilic cytoplasm that may appear vacuolated and a round dark-staining nucleus

Leydig cells are closely associated with capillaries
Function = secrete testosterone

Question 20

Rete testis

Answer 20

anastomosing network of tubules extending from apex of testicular lobules to vas efferens

Lined by simple cuboidal or squamous epithelium with one cilium per cell

Underlain by basal lamina and vascular CT

Question 21

Vas efferens

Answer 21

convoluted tubes emptying into epididymis (10-15 total)

Simple columnar epithelium (ciliated) with interspersed cuboidal cells

Surrounded by a thin band of circular smooth muscle

Microvilli on lumenal surface, epithelial cells absorb much of the fluid produced in seminiferous tubules

Question 22

epididymal duct

Answer 22

Epididymal Duct = efferent ductules merge to form a single duct

Tortuous path, acts as a long storage duct where sperm acquire motility

Lined by a PSC with stereocilia, active in secretion/reabsorption

Epithelium underlain by a thin lamina propria and a circular layer of smooth muscle

At its extreme lower end has inner longitudinal, middle circular and outer longitudinal layers; at upper end, peristaltic contractions move sperm to storage in lower end

Question 23

Vas deferens

Answer 23

ductus deferens = muscular-walled duct (3 layers); thick middle circular layer - peristaltic contractions transport sperm to urethra (emission)

Lined by PSC with fibroelastic lamina propria, stereociliated except at lower end (ampulla)

Longitudinal folds are present in mucosa

Divided into the spermatic cord and the ampulla

Question 24

Spermatic cord section of the vas deferens

Answer 24

in scrotum and inguinal canal, contains vas deferens, blood and lymph vessels, nerves and longitudinal strands of skeletal muscle

Question 25

Ampulla region of the vas deferens

Answer 25

dilated lower end with a highly folded mucosa and a less regular muscularis

Question 26

Ejaculatory duct

Answer 26

formed by merging of vas deferens and excretory duct of seminal vesicle to the urethra

Question 27

Genital glands: seminal vesicles (cell lining, secretion)

Answer 27

tortuous glandular diverticulum that empties into ejaculatory duct, secretes a viscous liquid contributing to semen (70-80% of semen volume) Epithelium is usually PSC but may be simple columnar Dependent on testosterone for glandular activity Mucosa is highly folded, surrounded by a smooth muscle coat (inner circular, outer longitudinal) and elastic adventitia

Question 28

Genital glands: prostrate gland (3 layers, cell lining, secretions)

Answer 28

surrounds urethra at its origin Actually is an aggregate of 30-50 compound tubuloalveolar glands Arranged in 3 layers: small mucosal glands (Central Zone) larger submucosal glands (Transitional Zone) large main prostatic glands toward periphery (Peripheral Zone) Surrounded by fibroelastic capsule, glandular material embedded in fibroelastic stroma with smooth muscle fibers Lined by PSC or simple columnar/cuboidal Secretes serous fluid that is rich in proteolytic enzymes that aid in liquification of semen; secretory state is dependent on testosterone In older glands, concretions may develop - represent condensation of secretions

Question 29

genital glands: bulbourethral gland

Answer 29

Bulbourethral Glands = paired glands, empty into urethra Compound tubuloalveolar gland Surrounded by a thin CT capsule inside a skeletal muscle layer, septa from capsule divide the gland into lobules Simple cuboidal to columnar glandular epithelium Secrete viscous mucous secretion acting as a lubricant for urethra

Question 30

Name the three genital glands

Answer 30

prostate seminal vesicles bulbourethral

Question 31

Describe the penis.

Answer 31

Composed of erectile tissue arranged into 3 columns bound to one another and surrounded by areolar CT and thin skin on outside paired corpora cavernosa dorsally single corpus spongiosum surrounding urethra Erectile tissue consists of irregular vascular spaces separated by dense fibroelastic CT and smooth muscle Possesses a rich nervous supply; parasympathetic stimulation results in relaxations of arterial walls leading to engorgement of vascular spaces with blood = erection