MALE REPRODUCTIVE SYSTEM

gametogenesis/ production of gametes

reproductive system produces gametes; sperm cells in the testes and oocytes in the ovaries

fertilization

the duct system in males nourishes sperm until they mature and are deposited into the female reproductive system and transported to the fertilization site

development and nourishment of a new individual

The female reproductive system nurtures a new individual in the uterus until birth and provides nourishment (milk) after birth

production of reproductive hormones

Hormones produced by the reproductive system controls its development and the development of the gender-specific body form. These hormones are also essential for the normal function of the reproductive system and for reproductive behavior.

gametes

testes in males & ovaries in females produce __

meiosis

how are the female and male gametes formed?

duplicated (identical copies of each other)

what happens to the chromosomes before meiosis?

chromatids

identical copies of chromosomes

one cell divide twice; form 4 daughter cells; chromosomes are reduced from 46-23

what happens during meiosis?

reduction division

the first cell division is also known as

mitosis

second cell division can be compared to?

second cell division

chromatids of the 23 chromosomes in each cell are separated

meiosis I & meiosis II

two divisions of meiosis

46-diploid number

each somatic cell has

22 autosomal + 1 sex chromosome

what is in the 23 homologous pairs

prophase I

chromosomes are duplicated (46) and consist of 2 chromatids joined by a centromere

synapsis (prophase I)

homologous chromosomes pair up; these pairs are referred to as tetrads (group of 4 chromatins)

crossing over (prophase I)

exchange of genetic material between chromosomes

metaphase I

chromosomes line up in the middle of the cell

anaphase I

homologous chromosomes separate

telophase I

new nuclei form & the cell divides; each daughter cell has 1 set of chromosomes or 23 chromosomes; each chromosome has 2 chromatids joined by a centromere

TRUE

T or F In meiosis II each of the 23 chromosomes in daughter cells still consists of 2 chromatids

prophase II

chromosomes consist of 2 chromatids

metaphase II

chromosomes line up at the equator

anaphase II

chromatids separate at the centromere

telophase II

each daughter cells receive 1 chromatid

chromosome

each of the chromatids is then called ___ again when centromere separate

4 daughter cells receive 23 chromosomes

what is produced after telophase II

testes; series of ducts (epididymides, ducta deferencia); accessory glands (seminal vesicles, prostate, bulborethral)
4. supporting structures (scrotum, penis)

male reproductive system consists of

testes and epididymis

sperm production and maturation

scrotum

a saclike structure containing the testes

incomplete connective tissue septum

divides the scrotum into left and right internal compartments

skin; loose connective tissue; smooth muscle

the wall of the scrotum includes

dartos muscle

contracts when cold; making the scrotum taught and wrinkled and reducing the surface area

cremaster muscle

a muscle that pulls the scrotum closer to the body in cold temperatures and relaxes to let the testicles be farther away from the body in warmer weather

testis

male gonad; oval organs 4-5 cm long within the scrotum

outer part of testis

consists of thick & white connective tissue capsule; the interior divides the testis into 250 cone-shaped lobules

seminiferous tubules

tightly coiled tubes; site of sperm production

interstitial cells or Leydig cells

outside seminiferous tubules; endocrine cells that secrete testosterone

tunica albuginea

a white fibrous capsule on the testes

spermatogenesis

the formation of sperm cells

12-14 years

at what age does the male's interstitial cells increase in number and size

74; 50

it takes __ days for sperm cells to be produced and ___ sperm cells are in seminiferous tubules

germ cells

a type of seminiferous tubule cell that divides and differentiates during spermatogenesis to form spermatozoa

Sertoli cells or sustentacular cells

a type of seminiferous tubule cell that is large and extends from the periphery to the lumen of the seminiferous tubule; nourish germ cells

dihydrotestosterone & estradiol

sustentacular cells are converted to

spermatogonia

most peripheral Germ cell divide by mitosis

primary spermatocytes

other daughter cells differentiate to form __ by meiosis

secondary spermatocytes

each primary spermatocyte completes the first meiotic division to produce

spermatids

undergo the last phase of spermatogenesis called spermiogenesis

sperm cells or spermatozoa

spermatids undergo major structural changes to form ___; develops the head, midpiece, flagellum

lumen of the seminiferous tubules (head- sustentacular cells; tail- the center of the lumen)

where are the developing sperm cells located?

head

what is directed toward the surrounding sustentacular cells

tail

what is directed toward the center of the lumen

nucleus

the head of the sperm contains___

acrosomes

the head of sperm that houses enzymes released to enter the egg

seminiferous tubules - series of ducts - the exterior of the body

it is transported to the __ after the production of sperm

rete testis

seminiferous tubules converge into a tubular network

efferent ductules

rete testis empties into 15-20 tubules

epididymis

a tightly coiled series of threadlike tubules that form a comma-shaped structure posterior on side of testis; sperm cells continue to mature here

capacitation

final changes in sperm after ejaculation

ductus deferens or vas deferens

carries sperm from the testis to the body cavity; about 45 cm long

ductus deferens or vas deferens

ascends along the posterior side of the testis medial to the epididymis

spermatic cord

associated with blood vessels and nerves to supply testis

ductus deferens; testicular artery and veins; lymphatic vessels; testicular nerve

each spermatic cord consists of

ampulla of the ductus deferens

an enlargement of the vas deferens diameter

seminal vesicle

sac-shaped gland; a short duct that extends from the __ to the ampulla of ductus deferens

ejaculatory duct

the duct from each seminal vesicle joins the ampulla of the ductus deferens; joins the urethra

urethra

20 cm long; passageway for both urine and male reproductive fluids; extends from urinary bladder to distal end of the penis

prostatic urethra

passes through the prostate gland

membranous urethra

passes through the floor of the pelvis and is surrounded by the external urinary sphincter

spongy urethra

extends the length of the penis and opens at the end

sympathetic reflex

what reflex causes the internal urinary sphincter to contract to keep semen from passing the urinary bladder

penis

the male organ of copulation

erection

engorgement of the erectile tissue with blood causes the penis to enlarge and firm

corpus cavernosum

2 columns of erectile tissue from the dorsal portion and the sides of the penis

corpus spongiosum

third smaller erectile column occupies the ventral portion of the penis

glans penis

the expanded distal end of the penis that forms a cap

external urethral orifice

the opening of the urethra to the outside

prepuce or foreskin

skin of the penis; loose fold of skin

circumcision

surgical removal of the prepuce

Accessory Glands

exocrine glands that secrete material into the ducts of the male reproductive tract

seminal vesicles

consists of many saclike structures; secrete thick, viscous, alkaline fluid containing nutrients (fructose, citric acid) and prostaglandins

prostate gland

both glandular and muscular tissue about the size and shape of a walnut; surrounds the urethra and 2 ejaculatory gland

prostate gland

a thin

bulbourethral glands or Cowper's glands

pair of small mucus-secreting glands located near the base of the penis; lubricate the urethra and end of the penis neutralizing urine residue

semen

the mixture of sperm cells and secretions from male reproductive glands; 60% of the fluid 30% prostate 5% testes and bulbourethral

semen

sperm cells & secretions from the accessory glands

2-5 mL

Normal volume of semen

50-150 mil

normal sperm cell count

Gonadotropin-Releasing Hormone (GnRH)

the hormone that stimulates activity in the gonads (testes and ovaries); stimulates the secretion of LH and FSH; to the anterior pituitary from the hypothalamus

luteinizing hormone (LH)

binds to interstitial cells in the testes and causes them to secrete testosterone; synthesis and secretion of testosterone; to interstitials cells of the testes from the anterior pituitary

Follicle-stimulating hormone (FSH)

supports spermatogenesis and inhibin secretion; promotes sperm cell development; to seminiferous tubules from the anterior pituitary gland

testosterone

development of reproductive organs; development and maintenance of secondary sexual characteristics; to testes, body tissue, anterior, hypothalamus from interstitial cells

inhibin

negative feedback effect; inhibits FSH secretion; to the anterior pituitary from sustentacular cells

relaxin

increase sperm motility; to sperm cells from prostate gland

puberty

the period of sexual maturation; during which a person becomes capable of reproducing

enlargement and differentiation of the male genitals • thicker, coarser, pigmented hair

examples of secondary sexual characteristics in males

male sex act

a series of reflexes that result in the erection of the penis

emission

movement of sperm cells