reproduction system - male and female development

embryological development

how baby’s body starts to form after sperm and egg come together

types of biological sexes

1. chromosomal sex

2. gonadal sex

3. phenotypic sex

4. secondary sex

chromosomal sex

• determined by sex chromosomes

  • Male (XY), Female (XX)

• mother always contributes an X = gamete always has an X chromosome

• chromosomal sex of the fertilizing sperm determines sex of embryo

  • sperm gives y chromosome = boy

  • sperm gives x chromosome = girl

• TDF

TDF

testis determining factor

• only present on Y chromosome

• little switch that promotes / tells body to develop into a male; develop male parts

gonadal sex

actual organs that make sex cells

if the embryo has..

• ovaries = female

• testes = male

all based on X or Y chromosome with TDF switch

phenotypic sex

what body looks like inside and outside

• primary sex characteristics

• secondary sex characterisitics

primary sex characterisitics

parts inside body that help with reproductive structures / making babies (ie. testes or uterus)

secondary sex characterisitics

outside parts / genitalia (ie. vagina or penis)

sexual indifferent stage

when both male and female embryos share the same structures / starting parts; stage where all babies have boy and girl parts and are deciding which set to keep (5 weeks after fertilization)

gonadal ridges

where gonads form

• medulla = testes

• cortex = ovaries

mullerian ducts

become female parts (uterus / oviducts)

wolfifian ducts

become male parts (epididymis / vas deferens)

formation of gonads

becoming boy or girl

week 7 for males

forming testes

week 8 for females

forming ovaries

primordial germ cells

come from yolk sac and travel to baby’s gonads (testes or ovaries) to seed them with stem cells that become gametes

1. spermatogonia

2. oogonia

spermatogonia

starter sperm cell

oogonia

starter egg cell

testes determines which duct system develops

1. testes produce testosterone after growing / developing

2. testes produce AMH

3. no testes

testes produce testosterone after growing and developing

testosterone tells wolffian duct to stay and development

testes produce AMH

AMH - anti mullerian hormone

• no ovaries or girl parts will be developed

no testes

female form develops passively

• no testes = no testosterone = no wolffian duct

• no testes = no AMH = mullerian ducts stays = development of female parts automatically

differentiation of external genitalia

1. male and female structures arise from same structures

2. during indifferent stage all embryos have…

   a. genital tubercle - a little bump

   b. urethral groove - a small opening

   c. urethral folds - two flaps near the grooe

   d. labioscrotal swellings - puffy areas on both sides

external genitalia begin to develop depending on presence of testosterone (8th week)

male genital tubercle

becomes penis

male urethral folds

fuse to form urethra

• tip of folds don’t fuse and becomes urethral opening

male labioscrotal swellings

fuse into scrotum (pouch that holds testes)

female genital tubercle

becomes clitoris

female urethral groove

becomes vestibule (area where pee and blood comes out)

female urethral folds

don’t fuse and become the labia minora (smallerr inner lips)

female labioscrotal swellings

don’t fuse and become labia majora (larger outer lips)

hormonal abnormalities

1. genetic male with testes but no testosterone

2. genetic male with testes and produces testosterone but no AMH (MIH)

3. genetic female with testosterone

genetic male with testes but no testosterone

embryo has female structures / genitalia

XY no TDF no testosterone no AMH = female genitalia (internal and external)

genetic male with testes and produces testosterone but no AMH (MIH)

has both male and female ducts but has external male genitalia

XY has TDF has testosterone no AMH = male genitalia (female internal, male external)

genetic female with testosterone

embryo has ovaries, male structures and genitalia

XX has TDF has testosterone no AMH = female internal, male external)

pseudohermaphrodites

gonads (testes / ovaries) dont match with external reeproductive system

hermaphrodites

baby have both ovarian and testicular tissues

pituitary events

1. ant pit. releases more FSH and LH between 10-14 years after birth

2. onset pberty is marked by LH release starts going up while sleeping

ovarian events (puberty in females)

1. increase in gonadotropins = ovaries producing estrogen

2. estrogen

3. follicle grows

4. ovulation starts 6-9 months after first period

estrogen

responsible for development of sexual characteristics

1. breast growth

2. fat redistribution

3. bone maturation

follicle growth

endometrium (uterus lining) grow = shedding of lining = first period (menarche)

• no egg released yet = no ovulation = no corpus luteum = no progesterone

puberty in males

1. controlled by testosterone levels

2. causes other things

testosterone levels

commes back @ age 12, reaches peak at 17, decreases after 50 years

causes of testosterone

1. size increase in internal , external genitalia

2. hair

3. muscle growth

4. voice deepens

5. growth spurt

testes

1. Found: scrotum

2. divided into 250-300 lobules

lobules

contains seminiferous tubules where sperm is made

seminiferous tubules

where sperm is made; connects to tubulus rectus which leads to rete testis which connects to efferent ductules which connect to epididymis

scrotum

• sac of skin, hangs outside abdomen

• holds testes / epididymis

• divided into 2 compartments - one testes per compartment

• responds to temp bc sperm needs to be at lower temp than core body

duct system

sperm travels from the testes to the outside via a series of ducts

accessory ducts

epididymis, ductus deferens, urethra

epididymis

first stop after sperm is made in testes

has 3 parts…

1. head

2. body

3. tail

• sperm enters epididymis from seminiferous tubule (nonmotive; sperm can’t swim)

• as they move through epididymis some become motile

• during ejaculation epididymis contracts vigorously and sperm exits epididymis through tail into ductus deferens

ductus deferens

carries sperm from epididymis through inguinal canal into pelvic cavity

• then joins with gland: seminal vesicle

ejaculatory duct

combination of ductus deferens and seminal vesicle

• duct passes into prostate gland

• during ejaculation muscle in walls of ducts deferens contracts: creating peristaltic wave that squeezes the sperm forward fast

vasectomy

ductus deferens are cut and tied off

urethra

final / terminal portion of male duct system

• carries both pee and sperm / semen

• runs throgh penis and has small opening

external urethral office

small opening at the tip of the penis

accessory glands

glands that add fluids that protect, feed, and help sperm travel

3 types..

1. seminal vesicles

2. bulbourethral glands

3. prostate gland

seminal vesicles

• secretions are 60% semen

• they make yellow, viscous, alkaline fluid

prostate gland

• secretions account for 30% semen

• they make milky, white acid fluid with citrate

• adds fluids to the sperm which makes semen

bulbouretheral glands

• produce thick, clear mucus

• clean out urethra by getting rid of any acid from urine

penis

• is a capulatory organ

• consists of

  • root

  • shaft (body)

  • ends in giant penis (tip)

  • foreskin (pice of loose skin on tip)

capulatory organ

organ that delivers sperm into female reproductive tract

internal anatommy of penis

1. spongy urethra

2. erectile tissue

3. erection

erectile tissue

3 long cylindrical bodies of smooth muscle and connective tissue

erection

vascular space fills with blood = penis enlarges and gets ridgid / straight which allows for penetration

semen

mixture of sperm and fluids / secretions from accessory glands

functions of semen

1. carries sperm

2. gives sperm nutrients

3. helps sperm move better

4. protects sperm by neutralizing acidity in vagina

ovary

• female gonad

• produces gametes

• produces hormones: estrogen and progesterone

• has ligaments

ligaments

1. ovarian ligament

2. suspensory ligament

3. broad ligament

ovarian ligament

anchors ovary to uterus

suspensory ligament

anchors ovary to pelvic wall

broad ligament

support uterine tubes, uterus, vagina

fallopian tubes

• uterine tubes: tiny tunnels that go from ovaries to the uterus

• site of fertilization (sperm and egg meet here)

• then transports fertilized egg to uterus

• has regions

fallopian tube regions

1. fimbriae

2. infundibuulum

3. amplla

4. isthmus

fimbriae

finger like parts that gently catch the egg from the ovary

infundibulum

funnel shaped part near the fimbriae

ampulla

middle and widest part where fertilization usually happens

ishtmus

narrow section that connects to the uterus

cilia

these beat in fimbrae and carry the oocyte into uterine tube

• uses smooth muscle contractions and beating to carry the egg along the tube