14.1 The Male and Female Reproductive System

gonads

organs that produce reproductive cells (testes and ovaries)

sex hormones

the chemical compounds that control the development and function of the reproductive system

gametes

sperm (males), ova/egg (female)

primary sex characteristics

reproductive organs, ducts, glands and other structures directly involved in reproduction

secondary sex characteristics

physical traits that develop during puberty but not directly apart of reproduction

seminiferous tubules

long coiled tubes that make up the testes; where sperm is produced (spermatogenesis)

interstitial cells

produces testosterone; located between seminiferous tubes

male primary sex characteristics

• gonads (testes)

• scrotum

• epididymis

• ductus deferens

• penis

• seminal vesicles

• prostate gland

• Cowper’s gland

male secondary sex characteristics

• facial/body hair

• deeper voice

• broader shoulders

• narrower hips

• coarse skin

• more obvious muscle development

female primary sex characteristics

• gonads (ovaries)

• oxiducts

• uterus

• cervix

• vagina

• vulva

female secondary sex characteristics

• minimal facial/body hair

• prominent breasts

• higher voice

• more rounded shoulders

• wider hips

• less prominent muscle development

urinary bladder

a muscular sac-like organ that stores urine before it leaves the body

ductus deferens

a tube that transports sperm from epididymis to urethra during ejaculation

urethra (m)

a tube that carries urine from bladder and semen during ejaculation outside of body

penis

organ that releases semen during reproduction into female reproductive tract

glans penis

a sensitive, rounded tip of penis. the urethral opening (where sperm and urine exits) is located here

foreskin

a fold of skin protecting the glans penis; can be sensitive

seminal vesicle

pair of glands located behind urinary bladder; produces mucus-like fluids containing fructose which provides energy for sperm, and prostaglandins

prostaglandins

trigger contractions of smooth muscle in female reproductive tract — assisting sperm movement

ejaculatory duct

carries semen into urethra during ejaculation and ensures urine and semen are not transported at the same time

prostate gland

produces alkaline fluid that reduces the acidity of female vagina, improving sperm survival

Cowper’s gland

releases pre-ejaculate which lubricates male urethra and reduces its acidity

epididymis

site of sperm storage and final maturation

testes

male gonads; produce sperm and testosterone

scrotum

a pouch of skin that consists of and regulates the temperature of testes

ureter

tube that transports urine from kidney to urinary bladder

spermatogenesis

spermatogonium (2n) → mitosis → two spermatocytes (2n) → each undergoes meiosis → four spermatids (n)

Figure 1

Sertoli cell

Figure 2

Spermatocytes/spermatids

Figure 3

Developing sperm

Figure 4

Interstitial cells

process of sperm development

1. developing sperm (spermatids) are supported and nourished by sertoli cells

2. from each testis, sperm is transported to epididymis

3. within each epididymis, the sperm mature and become motile

process of erection

1. penis shaft is made up of erectile tissue containing blood spaces

2. during arousal, nerve impulses cause muscle relaxion in arteries entering penis

3. erectile tissue fills with blood

4. veins leading away from penis constrict

5. penis becomes erect

process of ejaculation

1. vas deferens, seminal vesicles, ejaculatory duct and prostate gland all contract rhythmically

2. forces semen into/out of urethra

ejaculated semen (3-4mL) consists of

500 million sperm cells

semen is made up of four substances

• fructose and prostaglandins

• mucus

• alkaline buffer

• sperm cells

acrosome

contains enzymes that help sperm break through outer layers of egg during fertilization

head

contains the nucleus (DNA) and acrosome

middle piece

contains many mitochrondria and provides ATP for sperm movement

tail (flagellum)

uses whip-like motion to propel sperm movement

ovaries

female gonads; site of oogenesis — release eggs (ova) and hormones (estrogen and progesterone). alternates so only one ovary produces an egg each month

follicles

a single, immature ovum develops in each follicle. protects and nourishes egg. site of estrogen production

estrogen is produced in

follicles within ovary

ovulation

each month, a single follicle matures and ruptures, releasing the egg into the oviduct

fimbriae

sweep/guide egg into oviduct during ovulation

oviduct (fallopian tube)

transports egg from ovary to uterus using muscle contractions (peristalsis) and cilia. site of final maturation and fertilization

uterus (womb)

muscular organ that holds and nourishes a developing fetus

endometrium

inner lining of uterus which is supplied with blood vessels to provide nutrients to fetus. thickens each month in preparation of fertilized egg

menstruation

endometrial lining is shed if no fertilized egg is present

cervix

opening from uterus to vagina; contains cervical glands that produce a mucus which blocks the spread of bacteria and aids sperm mobility

vagina

canal that receives penis and allows the birth of baby and menstrual blood out of body. lubricated by cervical glands and is acidic

urethra (f)

only carries urine out of body

vulva

external part that includes labia majora/minora (skin folds), clitoris and urethral/vaginal openings

follicular phase

primary oocyte (2n) present at birth splits into secondary oocyte (n) upon ovulation forms an egg — becomes either fertilized or lost