BIOL 65 chapter 26: the reproductive system

sexual reproduction involves

2 parents

gametes

sex cells

sperm's function in sexual reproduction

motility for achieving contact

egg's function in sexual reproduction

nutrition for developing embryo

zygote

fertilized egg

males have

- XY chromosomes

- penis for introducing sperm

females have

- XX chromosomes

- vagina for receiving sperm

Primary sex organs (gonads)

male = testes

female = ovaries

secondary sex organ (female)

uterine tubes, uterus, vagina

secondary sex organ (male)

ducts, glands, penis

external genitalia (male)

penis and scrotum

external genitalia (female)

mon pubis

labia majora

labia minora

clitoris

vaginal orfice

vestibular bulbs

vestibular glands

paraurethral glands

internal genitalia (male)

testes

epididymides

ductus deferentis

seminal vesicles

prostate

bulbourethral glands

ejacteral glands

internal genitalia (female)

ovaries

uterine tube

uterus

vagina

secondary sex characteristics

facial, axillary, pubic hair

acne

diploid

DNA combination resulting in our double-stranded chromosomes (DNA from mom and dad) - all cells except sperm/egg

haploid

DNA combination resulting in a single stranded chromosomes (only cells are sperm/egg)

meiosis I

first division

meiosis II

second divison

early prophase I (starts diploid)

- Chromatin condenses to form visible chromosomes

- Each chromosome has 2 chromatids joined by a centromere

mid to late prophase I

- homologous chromosomes form pairs (tetrads)

- Chromatids often break and exchange segments (crossing-over)

- Centrioles produce spindle fibers

- Nuclear envelope disintegrates

metaphase I

Tetrads align on equatorial plane of cell w/ centromeres attached to spindle fibers

anaphase I

Homologous chromosomes separate and migrate to opposite poles of the cell

telophase I

- New nuclear envelopes form around chromosomes

- Cell undergoes cytoplasmic division (cytokinesis)

- Each cell = haploid

prophase II

- Nuclear envelopes disintegrate again

- Chromosomes still consist of 2 chromatids

- New spindle forms

metaphase II

Chromosomes align on equatorial plane

anaphase II

- Centromeres divide

- Sister chromatids migrate to opposite poles of cell

- Each chromatid now constitutes a single-stranded chromosome

telophase II

- New nuclear envelopes form around chromosomes

- Chromosomes uncoil and become less visible

- Cytoplasm divides

final product of meiosis II

4 haploid cells with single-stranded chromosomes

Scotum

Pouch that contains testes

median septum contains

Perineal raphe = external seam

spermatic cord contains

- Ductus deferens

- Nerves

- Vessels

- Inguinal canal to pelvic cavity

What helps temperature regulation?

- cremaster

- dartos muscle

- pampiniform plexus

cremaster

internal oblique muscle elevates testes

dartos muscle

smooth muscle wrinkles scrotum

pampiniform plexus

vein network of spermatic cord

testes connective tissue

- Tunica vaginalis

- Tunica albuginea

testes contains

hundreds of lobules of 1 to 3 seminiferous tubules

germinal epithelium contains

- germ cells = becomes sperm

- nurse cells = help make blood-testis barrier

interstitual endocrine cells

between tubules make testosterone

rete testis

beginning of sperm maturation process

Spermatogenesis process

1. Type A spermatogonium undergoes mitosis forming one Type A and one Type B spermatogonium

2. Type B spermatogonium becomes primary spermatocyte

3. Primary spermatocyte undergoes meiosis I forming two haploid secondary spermatocytes

4. The secondary spermatocytes undergo meiosis II forming 4 haploid spermatids

5. Spermatids differentiate into sperm (spermiogensis)

head of spermatozoa contains

- Nucleus

- Acrosome = enzymes

- Flagellar basal body

tail of sperm contains

- Midpiece = many mitochondria for energy

- Principle piece of tail

- End piece of tail

spermatic ducts

- efferent ductules

- epididymis

- ductus deferens

- ejaculatory duct

- urethra

effernet ductules

- Posterior testis

- Carry sperm to epididymis

Epididymis

- Head, body, and tail

- Sperm storage and maturation

ductus deferens

- Long tube with smooth muscle in wall

- Ampulla is widened last portion

ejaculatory duct

- Passes through prostate

- Empties into urethra

urethra

Prostatic, membranous, spongy

accessory glands (males)

- seminal vesicles

- prostate

- bulbourethral glands

seminal vesicles

- Pair of glands, posterior to bladder

- Empty into ejaclatory duct

prostate

- Surrounds urethra and ejaculatory ducts

- Empties into urethra

Bulbourethral glands

- Pair of glands near base of penis

- Secretes clear fluid that neutralizes urethra, lubricates head

components of semen

- 2 to 5 ml per ejaculation

- 10% sperm

(Sperm count: about 50 to 120 million/mL)

- 30% prostatic fluid

- 60% seminal vesicle fluid

the penis contains

- internal root

- shaft

- glans [head (frenulum)]

- prepuce (foreskin)

- erectile tissue

corpus spongiosum

- Glans of the penis

- Contains spongy urethra

corpora cavernosa

Contains deep artery

ovary structures

- tunica albuginea

- medulla

- cortex

- follicles

tunica albuginea

capsule around ovary

medulla of ovary

fibrous connective tissue with blood vessels

cortex of ovary

contains ovarian follicles

follicles of ovary

contains egg and supporting follicular (granulosa) cells

oogenesis contains

- primary oocyte (diploid)

- secondary oocyte

primary oocyte

completes meiosis I forming one secondary oocyte and one polar body (both haploid)

secondary oocyte

ovulated and will complete meiosis II if fertilized (produces and discards a second polar body)

Folliculogenesis contains

- primordial follicle

- primary follicle

- secondary follicle

- tertiary follicle

- preovulatory (graafian) follicle

primordial follicle

egg and one layer of follicular cells

primary follicle

larger egg, one layer of cuboidal follicular cells

secondary follicle

larger egg, two or more layers of granulosa cells

tertiary follicle

contains fluid-like pockets or a single fluid filled antrum among granulosa cells

preovulatory follicle

- large blister bulging from ovary

- contains cumulus c with zona pellucida as inner layer

what happens on day 14 of menstrual cycle

ovulation of secondary oocyte from mature (graafian) follicle

corpus luteum

collapsed follicle

if there is no pregnancy, what happens to corpus luteum

becomes corpus albicans (a scar)

uterine tubes (fallopian tubes)

ciliated tube from ovary to uterus

fimbriae of uterine tube

- project from infundibulum toward ovary

- perform a sweeping motion over ovary to draw oocyte into the tube (not connected)

ampulla

middle segment of uterine tube

isthmus

narrow, near uterus segment of uterine tube

uterus

A muscular chamber superior to vagina for nourishment, protection, and delivery of fetus

uterus sections

- Fundus

- Body

- Cervix

- Cervical canal = (with cervical glands) = connects to vagina

uterine wall

- perimetrium

- myometrium

- endometrium

perimetrium

external serosa layer

mymetrium

smooth muscle

endometrium

- functional layer = superficial, shed during menstruation

- basal layer = regenerates new lining every month

vagina

distensible wall of mucosa, muscularis, and adventitia

vagina consists of

- fornices

- vaginal rugae

- hymen

fornices of vagina

superior extensions around cervix

vaginal rugae

friction ridges and allows for distension during sexual intercourse and childbirth

hymen

membrane across opening

Vulva (pudendum)

female external genitalia

mons pubis

anterior mound

Labia majora (majus)

thick fold between thighs

Labia minora (minus)

hairless, thin, medial folds

Vestibule

area enclosed by labia minora

Clitoris

erectile; area of sexual stimulation

clitoris consists of

- glans

- body

- crura

prepuce

hood of clitoris

vestibular bulbs

erectile tissues deep to labia majora

glands provide

lubrication to vestibule and vagina

- greater & lesser vestibular glands

- paraurethral glands