reproductive systems - exam

Scrotum

The scrotum is a sac of loose skin and subcutaneous tissue that contains the testes.

A vertical internal septum divides it into two sacs

Each sac contains one testis

How does the scrotum regulate temperature for sperm?

The scrotum keeps the testes cooler than body temperature for sperm survival.

Cold: cremaster muscle + dartos muscle contract → testes move closer to body (warm up)

Warmth: muscles relax → testes move away from body (cool down)

cryptorchidism

Failure of the testes to descend

What are seminiferous tubules and their function?

seminiferous tubules are tubes inside the testes where sperm are made.

Functions:

Produce sperm

Carry sperm out of the testes

Secrete fluid for sperm transport

Secrete inhibin

What is testosterone and where is it produced?

testosterone is the main male sex hormone produced in the testes.

What is spermatogenesis?

spermatogenesis = production of haploid sperm in the seminiferous tubules.

Begins with diploid spermatogonia

What is meiosis in sperm production?

meiosis produces 4 genetically different haploid cells.

One precursor cell → 4 sperm

What is the structure and function of sperm?

sperm consist of head, midpiece, and tail.

Produced at ~300 million/day in the testes

Survive about 48 hours in the female reproductive tract

Function: fertilize a secondary oocyte

What is GnRH and what does it do?

GnRH (gonadotropin-releasing hormone) is released at puberty and stimulates the anterior pituitary to release LH and FSH.

What is LH and what is its function in males?

LH (luteinizing hormone) stimulates testosterone production and helps support spermatogenesis.

What is FSH and what is its function in males?

FSH (follicle-stimulating hormone) stimulates spermatogenesis in the testes.

What are the main functions of testosterone?

Growth & maintenance of male reproductive organs

Sperm maturation

Bone growth & protein synthesis

Development of male secondary sex characteristics

Reproductive System Ducts in Males next up

Pathway of sperm in the testes

seminiferous tubules → straight tubules → rete testis

Epididymis

Sperm enter through efferent ducts

Travel into the ductus epididymis

Stored for several months

Old sperm degenerate and are reabsorbed

What is the ductus (vas) deferens and what is its function?

The ductus deferens is a tube that exits the epididymis and travels through the spermatic cord into the pelvis.

Loops over the ureter

Passes behind the urinary bladder

Stores sperm and propels them toward the urethra during ejaculation

What is the spermatic cord and what does it contain?

The spermatic cord is a supporting structure of the male reproductive system.

Contains:

ductus deferens

testicular artery

Autonomic nerves

Testicular veins

Lymphatic vessels

cremaster muscle

The union of the ducts from the seminal glands and two ductus deferens forms the..

ejaculatory ducts

The function is to eject spermatozoa into the prostatic urethra

urethra

The urethra is the duct shared by the reproductive and urinary systems

Both semen and urine pass through the urethra

The urethra passes through the prostate gland (prostatic urethra), deep muscles of the perineum (membranous urethra), and the penis (spongy urethra)

Accessory Sex Glands - seminal glands (vesicles)

Secrete alkaline, viscous fluid containing:

Fructose → energy (ATP) for sperm

Prostaglandins → enhance sperm motility & viability

Clotting proteins → coagulate semen after ejaculation

Alkaline fluid neutralizes acidity in male urethra & female reproductive tract

Accessory Sex Glands - prostate

surrounds the prostatic urethra and secretes a milky, slightly acidic fluid

Accessory Sex Glands - Bulbourethral

secrete an alkaline fluid during sexual arousal that neutralizes acids from urine in the urethra and mucus for lubrication

Semen (seminal fluid)

Mixture of: sperm + accessory gland secretions

Functions:

Provides fluid and nutrients for sperm

Neutralizes acidity of male urethra & female vagina

Contains seminal plasmin (antibiotic)

Prostatic enzymes coagulate then liquefy semen → aids sperm movement through cervix

Volume & concentration: 2.5-5 mL/ejaculate, 50-150 million sperm/mL

Penis - structure and function

Function: Male organ of copulation; passageway for semen and urine

Parts: Root, body, glans

Composition:

2 corpora cavernosa (erectile tissue)

1 corpus spongiosum (surrounds urethra)

Glans: Head, covered by prepuce (foreskin)

what is prepuce

foreskin

erection

Controlled by: Parasympathetic nervous system

Mechanism:

Parasympathetic stimulation → vasodilation of arterioles in erectile tissue

Blood flows into dilated sinuses → tissue engorges → erection

Ejaculation

propulsion of semen from the urethra to the exterior, is a sympathetic reflex.

Which of the following correctly traces a sperm from its formation to ejaculation?

seminiferous tubules → straight tubules → rete testes → epididymis → ductus deferens → ejaculatory duct

ovaries

paired glands

held in position by the broad ligament, ovarian ligament, and suspensory ligament

Ovaries produce gametes (mature into ova)and hormones (progesterone, estrogens, inhibin, relaxin)

Ovarian structures and functions

Ovarian follicles: contain oocytes + follicular & granulosa cells

Tertiary (Graafian) follicle: mature, ready to release secondary oocyte

Corpus luteum: forms after ovulation; secretes progesterone, estrogens, inhibin, relaxin

Oogenesis

Oogenesis: formation of gametes in the ovaries

Produces 1 haploid secondary oocyte + 1 haploid first polar body

At ovulation, both enter uterine tube; if fertilized, secondary oocyte completes meiosis II → ovum + second polar body

Ovum + sperm → zygote

Ovarian cysts

fluid filled sacs in the ovary, are relatively common and usually not cancerous

Uterine Tube (Fallopian Tube)

Function: Pathway for sperm → ovum; secondary oocyte/fertilized ovum → uterus

Regions:

Infundibulum - near ovary, has fimbriae

Ampulla - widest, longest portion

Isthmus - narrow portion joining uterus

Epithelium: Simple ciliated columnar

Movement: Cilia + peristalsis move oocyte toward uterus

Uterus Layers

Perimetrium (serosa): Outermost layer

Myometrium: Middle, 3 layers of smooth muscle

Endometrium: Inner layer

Functional layer: Shed during menstruation

Basal layer: Permanent; regenerates new functional layer

Secretory cells of the cervix produce

Produced by secretory cells of the cervix

During ovulation: Less viscous & more alkaline → aids sperm survival and movement

When viscous: Forms cervical plug → blocks sperm penetration

Provides energy for sperm movement

Mammary Glands

Modified sweat (sudoriferous) glands located over pectoralis major and serratus anterior muscles

Functions: synthesize, secrete, and eject milk → lactation

Skin around nipple: areola

ovarian cycle

changes that occur during and after maturation of the oocyte

uterine cycle

involves changes in the endometrium that prepare it for implantation of the developing embryo

GnRH (Gonadotropin-Releasing Hormone)

Source: Hypothalamus

Function: Stimulates anterior pituitary to release FSH and LH

Role: Controls menstrual and ovarian cycles

FSH (Follicle-Stimulating Hormone)

Source: Anterior pituitary

Function: Stimulates initial development of ovarian follicles

Role: Promotes estrogen secretion

LH (Luteinizing Hormone)

Source: Anterior pituitary

Function: Stimulates further follicle development, ovulation, and estrogen & progesterone secretion

Estrogen(s)

Source: Ovarian follicles

Function: Promote female secondary sex characteristics, uterine lining growth, and follicle maturation

Promote the development and maintenance of female reproductive structures, secondary sex characteristics, and the breasts

Increase protein anabolism and build strong bones

Lower blood cholesterol

Feedback loop involving GnRH, LH and FSH

relationship of estrogen and progesterone

Progesterone works with estrogens to prepare the endometrium for implantation and the mammary glands for milk synthesis

Phallectomy/penectomy

removal of penis

Orchiectomy

removal of testicles

Vaginoplasty

surgical formation of a vagina

Clitoroplasty

formation of a clitoris

Labiaplasty

formation of labia

Phalloplasty

formaiton of penis

Scrotoplasty

formation of scrotum

Metoidoplasty

increase length of clitoris

Four phases of human sexual response

excitement, plateau, orgasm, and resolution

Excitement phase

vasocongestion (engorgement with blood) of genital tissue

Plateau phase:

few seconds to many minutes

Sex flush - rash like redness

Orgasm (climax)

rhythmic muscular contractions and pleasurable sensations

Refractory period

males only - the time after ejaculation during which a man cannot achieve another erection or orgasm.

Resolution

profound relaxation - genital tissues heart rate, blood pressure, breathing, and muscle tone return to the unaroused state

Puberty

Period when secondary sexual characteristics develop and reproductive capability is reached.

~Age 10: hormone-driven changes begin

Males: start producing sperm

Females: begin menarche (first menstruation)

fertility decline in women

between 30-40 years of age, ovarian follicles become exhausted and estrogen levels decline

Menarche

The first menstrual period in females, marking the start of the monthly reproductive cycle.

Female Reproductive Aging & Menopause

Between ages 40-50, ovaries respond less to gonadotropins → ↓ estrogen & progesterone → follicles fail to develop.

Symptoms:

hot flashes, sweating, headaches, vaginal dryness, mood changes, weight gain.

Increased risk: osteoporosis, uterine cancer, breast cancer.

Male Reproductive Aging

Testosterone gradually declines → ↓ muscle strength, sexual desire, and viable sperm.

Most men >60 develop benign prostatic hypertrophy (prostate 2-4× normal size).

Reproductive capacity often retained into 80s-90s.

Testicular & Prostate Disorders

Testicular Cancer:

Originates in sperm-producing cells; most common in men 20-35.

Monthly self-exams recommended after warm bath/shower: roll each testis gently to check for lumps, hardness, or changes.

Prostatitis:

Acute: prostate swollen & tender.

Chronic:

common in middle/older age; enlarged, soft, very tender, irregular surface.

Prostate Cancer:

Major cause of cancer death in men.

Treatments: surgery, radiation, hormonal therapy, chemotherapy.

Endometriosis

growth of endometrial tissue outside the uterus

breast cancer

Second-leading cause of cancer death in women.

Rare before age 30; incidence rises after menopause.

Genetic risk: BRCA1 and BRCA2 genes.

Early detection: breast self-exam & mammography improve survival.