PT 505 Male Reproductive system

gametes

sex cells

egg (zygote)

gametes combine their genes to form:

sperm

Gamete with motile properties

egg, ovum

gamete containing nutrients for developing zygote

primary sex organs (gonads)

produces gametes (testes or ovaries)

secondary sex characteristics

Organs other than the gonads

secondary sex characteristics

nonreproductive sexual characteristics, such as female breasts and hips, male voice quality, and body hair, that develop at puberty to attract a mate

23

# of pairs of chromosomes our cells contain

1

# of pairs of sex chromosomes

sperm

Sex of child is determined by the chromosomes on what gamete?

False

Sex determination ends with fertilization. True or false?

genetics, hormones

Sex determination depends on what two things?

5-6 weeks gestation

When do gonads begin to develop?

Wolffian ducts (mesonephric)

Early embryonic ducts that can develop into male internal genitalia under the proper stimulation (testosterone).

Mullerian ducts (paramesonephric)

Duct that develops into the female reproductive tract

males

the sex determining region of the Y chromosome (SRY) is is present in what sex?

SRY gene

Codes for a protein that causes development of testes and inhibits mullerian duct formation

hormones

Female development occurs in the absence of _________________

Homologous sexual structures

male and female organs that develop from the same embryonic structure

genital tubercle

becomes the head (glans) of the penis or glans clitoris

pair of urogenital folds

encloses male urethra helping to form the penis or forms the labia minora

pair of labioscrotal folds

becomes either scrotum or labia majora

12 weeks

When does our embryonic development become distinclty male or female?

testosterone

Descent of testes is initiated by what hormone?

inguinal canal

When testes begin to descend, they pass from the abdominal cavity near the kidney through _______________ to scrotum

gubernaculum connective tissue

What guides the testes during their descent to the scrotum?

cryptorchidism

undescended testicles prevalent in 3% of the population

2-3º centigrade

Sperm production requires a temperature about ________________________ below core body temp

cremaster muscle

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

dartos muscle

smooth muscle; wrinkles scrotal skin; pulls scrotum close to body

pampiniform plexus

Network of veins ascending near the testicular artery that work as a countercurrent heat exchanger to cool arterial blood entering the testis

tunica albuginea

white fibrous capsule on testes that also creates a septa to penetrate testis and divide it into lobules

seminiferous tubules

Where is sperm produced?

seminiferous tubules

Each testicular lobule contains 1-3 of these structures.

Interstitial Leydig cells

Structures between seminiferous tubules that produce testosterone

Germinal epithelium

Several layers of germ cells in the process of becoming sperm that line the lumen of the seminiferous tubules

Sustentacular sertoli cells

in between germ cells
Protect the germ cells, and promote their development
Germ cells depend on them for nutrients, waste removal, growth factors, and other needs

Blood-testis barrier

This is provided by the sertoli cells. They create a tight junction which prevent blood from making antibodies to destroy developing sperm.

False

Sperm swims in the male. True or false?

low, poor

______ BP of testicular artery leads to _______ O2 supply

mitochondria

Due to low BP of testicular arteries, sperm develop very large _____________________

T10

Testicular nerves are formed from what spinal cord segment?

efferent ductules

12 small ciliated ducts collecting sperm from rete testes and transporting it to epididymis

epididymis

site of sperm maturation and storage , allowing for fertility for 60 days

epididymis

Sperm are physiologically immature when they leave the testis and mature as they travel through the ____________

ductus deferens

muscular tube passing up from scrotum (in spermatic cord) through inguinal canal and passes between bladder and ureter

seminal vesicle

Ductus deferens ends by uniting with what duct?

Ejaculatory duct

2 cm duct formed from ductus deferens and seminal vesicle

urethra

Extends from urinary bladder to distal end of penis functioning as a passageway for urine and male reproductive fluids

prostatic urethra, membranous urethra, spongy or penile urethra

Three parts of urethra

prostatic urethra

Where the urethra passes through the prostate.

membranous urethra

extends through perineum (muscular floor of pelvis; urogenital diaphragm)

spongy or penile urethra

Passes through the penis with several minute mucus-secreting urethral glands that empty

seminal vesicles, prostate gland, bulbourethral glands

Accessory male reproductive glands

seminal vesicles

pair of glands that join with each vas deferens to empty in the ejactulatory duct, producing around 60% of semen

prostate gland

Surrounds urethra and ejaculaoty duct and is just inferior to the bladder, producing 30% of semen

citric acid

Think milky secretions of prostate gland contain:

fibrinogen, fructose, prostaglandins

Secretions from seminal vesicles contain:

Bulbourethral glands (Cowper's gland)

Accessory glands that secret mucus just before ejaculation, contributing to roughly 5% of semen

mixture

Semen is a ___________________

seminiferous tubules, seminal vesicles, prostate, bulbourethral glands

Semen consists of secretions from what four structures?

50-150 million

# of sperm per ml

20

If sperm concentration falls below ______ million, per ml, then they are likely to be infertile

alkaline

pH of sperm is slightly ______________

urination, injecting sperm, erection

Functions of penis

dorsal

top of penis

ventral

bottom of penis

corpora cavernosa (2), corpus spongiosum (1)

columns of erectile tissue that engorges with blood

glans penis

enlargement of corpus spongiosum

prepus (foreskine)

covering of glans penis

dormant

Reproductive system remains ___________ for years after birth

Adolescence

Onset of gonadotropin secretion and reproductive development until a person attains full adult height

12 years

Puberty onset age in girls

13 years

Puberty onset age in boys

GnRH

Hormone produced from hypothalamus that travels to anterior pituitary and stimulates gonadotrope cells to secrete FSH and LH

LH

hormone that stimulates interstitial cells of testicle to produce testosteron

FSH

Hormone that stimulates sustentacular cells to secrete androgen-binding protein that interacts with testosteron to stimulate spermatogenesis

spermatogenesis

Testosterone stimulates what process in the presence of ABP?

inhibits

testosterone ____________ GnRH to hold LH and FSH in check via negative feedback

secondary

Testosterone stimulates the development of _______________ sexual organs

growth spurt

Effect of testosterone playing a role in increasing muscle mass, basal metabolic rate, and larynx

testosterone

Hormone that is responsible for erythropoiesis, increasing hematocrit and RBC count in men higher than women

libido, spermatogenesis, reproductive tract

What three things does testosterone sustain during adulthood

inhibin

inhibits secretion of FSH and therefore sperm production

spermatogenesis

Formation of sperm

primordial germ cells

stem cells destined to become sperm

spermatogonia

Cells that lie along periphery of seminiferous tubule outside the blood testis barrier and multiply by mitosis to produce two types of daughter cells

Type A, Type B

Types of daughter cells that spermatogonia produce

Type A

Spermatogonia daughter cells that remain outside the BTB and will multiply from puberty to death

Type B

Spermatogonia daughter cells that migrate and differentiate into primary spermatocytes and secondary spermatocytes

Primary spermatocytes

Pass through the BTB and move into lumen of tubule

secondary spermatocytes

Once outside BTB, primary spermatocytes undergo meiosis I, creating 2:

23

# of chromosomes in secondary spermatocytes

no

Do secondary spermatocytes continue to replicate?

meiosis II

when chromosomes line up in single file along metaphase plate and the two chromatids of each chromosomes separate

spermatids

The four haploid cells that result from meiosis

4

A single primary spermatocyte produces _____ spermatids via two rounds of cell division

haploid spermatids into sperm

Final stage of spermatogenesis

false

Division occurs in the final stage of spermatogenesis. true or false?

acromosome

Hat of spermatid nucleus that forms during the final stage of spermatogenesis