2130 unit 8

reproductive system

GOAL → make gamete & pass on genes into new organism

ACTION → meiosis (reg by hormones)

X focus homeostasis

key terms

nucleosome (DNA packed around histone) → nucleosome be sister chromatids & join → chromosomes

diploid = 2n

• # distinct chromosomes → each cell 23 chromosomes pairs

• 23 sperm + 23 oocyte = 46 chromosomes = 1 diploid cell

• cell replicate = 2n & 2 copies

haploid = n

• # distinct chromosomes w/ 1/2

• cell split after 1/2 DNA to 1 daughter cell & 1/2 other

gamete = haploid cells during fertilization

• in gonads of parents

• make diploid w 2n

germ line cells = cells in goands make gametes during meiosis

fertilization & chromosomes

• each cell = 23 chromosome pairs (2n) → 1 pair = sex chromosomes

• sex chromosomes = big X, small Y

  • oocyte = X

  • sperm = X or Y

  • XX = AFAB likely
    XY = AMAB likely

meosis

diploid cell becomes a haploid GAMETE

then used in fertilization to make a gamete

meosis I steps

INTERPHASE I

• DNA replicates, 2 copies of each chromosome (46 total)

PROPHASE I

• Homologous pairs of sister chromatids (1 from each parent) form tetrad

• THEN opposing sister chromatids cross over & recombination occur

• INC genetic variation

METAPHASE I

• sister chromatids line up

• homologous pairs separated

ANAPHASE I

• separate in anaphase via spindle fibers

• each daughter cells will have 23 distinct chromosomes (2N-> N)

TELOPHASE I & CYTOKENESIS

• 2 daughter cells form w cleavage & separation

• each cell w/ 1 set sister chromatids

• has 46 chromosomes BUT 23 distinct chromosomes (DNA compliment N)

What is the end result of meiosis I?

2 haploid daughter cells

46 chromosomes BUT only 23 distinct chromosomes

meosis II steps

X DNA replication

PROPHASE II

• chromatins condense to chromosomes

• new spindle fiber form

METAPHASE II

• spindle fibers attach to pull apart sister chromatids

ANAPHASE II

• sister chromatids separated

TELOPHASE II & CYTOKENESIS

• cleavage w each daughter cell split into 4 total diff sex cells

• THUS → 4 genetically distinct cells w 23 chromosomes (DNA compliment N)

What is the end result of meiosis II?

4 haploid(n) gamete daughter cells w 23 chromosomes

how are feedback loops involved in reproduction?

• dvlp of each reproductive system X start ASAP post fertilization

• fuck up feedback loop = rpxdtn issue

• use (-) & (+) feedback loops to regulate gamete pxdtn

• (-) loops→ hormone balance by DEC GnRH + gonadotropins (LH + FSH) when high enough & prevent overpxdtn gametes

• (+) loops → INC LH bc INC estrogen = ovulation to release mature egg

biological male reproductive system

EXTERNAL

• penis

• scrotum

INTERNAL

• penis → urethra, erectile penis tissue

• scrotum → testes, epididymis

• vas deferens

• ureter

• bladder

• seminal vesicle

• ejaculatory duct

• prostate

• bulbourethral gland

• rectum

scrotum

flesh sac hold testes + epididymis

testes

• inside scrotum

• site sperm pxdtn

• site hormones → testosterone + inhibin

  • both respond to gonadotropins from anterior pituitary

epididymis

sit on top of testes in scrotum

site sperm maturation & storage

vas deferens

tube connect testes → urethra

send sperm during ejaculation

ureter

connection to kidney & bladder

sends urine via urethra to penis

bladder

landmark next to seminal vesicles & prostate

store urine

connect ureter w tube (run thru prostate)

penis

• organ excrete urine & sperm

• made mainly of erectile tissue

• site sperm transfer during ejaculation/s ex

urethra

tube carry urine & sperm → penis & out of body

connect to testes 4 sperm ejaculation

ejaculatory duct

run thru prostate

drains into urethra 4 empty sperm & seminal fliud

junction of vas deferens & seminal vesicles

seminal vessicle

• organ near bladder & above prostate

• USE → add to seminal fluid (semen) during ejaculation

  • fluid = rich in fructose + enzymes give sperm E

bulbourethral gland

• under prostate as small bulb

• USE → release neutralizing & lubricating fluid into urethra before ejaculate

  • fluid = alkaline to neutralize acidic urethra before pee (carry pee & semen)

• ACTION → release fluid during arousal, before seminal vesicle & prostate & give fluid during cumming to protect sperm

prostate

• gland under bladder

• connects to urethra

• USE → secrete enzyme & alkaline fluid neutralize acidic urethra & vagina enviro so sperm live

• GROW → reg w testosterone

rectum

• landmark

• store feces till poo via anus

pathway of FLUID release during ejaculation

1. Bulbourethral Gland

   1. secretes clear, lubricating fluid → clean & lubricate urethra before ejaculation during arousal

   2. give to fluid post seminal vesicle & prostate

2. Seminal Vesicle

   1. give thick, nutrient-rich fluid → LOTS fluid + E

3. Prostate

   1. secretes fluid to nourish sperm & neutralize acidity → good f(x) & protected

pathway of SPERM release during ejaculation

1. Seminiferous tubules → sperm cells made here

2. epididymis → sperm moves & store ontop of testes

3. vas deferens → ejaculation occur & contract to pump sperm from scrotum thru thus to pelvic cavity

4. ejaculatory ducts → vas deferens join seminal vesicles @ ejaculatory duct & add fluid

5. prostate → fluid move past to urethra & add fluid

6. urethra → sperm pass prostate & add fluid to make semen & sent thru to penis

7. penis → seme exit via opening

testicular anatomy & function

• seminiferous tubule → site of spermatogenesis & start of sperm dvlp (meiotic actions occur)

• rete testis → sperm cont. dvlp & pushed here

• efferent ductules → sperm pushed here from rete testis to go to epididymis (conected)

• epididymis → sperm sit here from efferent ductules (2-3 weeks & mature)

• tubulus rectus → connection site rete testis + seminiferous tubule

• vas deferens → connect urethra & testes

seminiferous tubules

(1) spermatocytes

• adult stem cells → itself +daughter cell when divide

• dvlp sperm cells

(2) sertoli cells

• support & reg spermatogenesis → build micro enviro

• FSH receptors

• make inhibin → inhibit release of gonadotropin

• blood testes barrier → tight junctions w sertoli cells

(3) leydig cells

• make testerone → reg sprm pxdtn

• inbtwn seminferous tubules

• LH receptors

(4) lumen → internal empty space that sperm travel toward

blood testes barrier

• tight junctions w sertoli cells

• prevent immune system destory spermatocytes

how do sertoli cells help spermatogenesis?

• build micro enviro to support & regulate

• ACTION → testes blood barrier (tight junctions w sertoli cells) allow spermatocytes move btwn sertoli cells when differnetiate

• THEN → sertoli cells release cytokins & peregrine factors to lumen

• THEN → condition spermocytes, reg meiotic division

what hormoes stimulate the cells of the seminiferous tubules?

anterior pituitary = GnRH

Leydig cell = anterior pituitary

Sertoli cell = FSH

What is spermatogenesis?

• DEF → mitosis & meiotic dvision from spermatogonium to spermatids

• CAUSE → T pxdtn = sperm pxdtn start w/ puberty

• LOCATE → seminiferous tubules

• PXD → 4 gametes from 1 cell (haploid gametes)

based on hypothalamic-pituitary-gonadotropin axis

SPERMAtogenesis process

1. spermatogoniua (2n) divide w mitosis → new spermatognium (2n) + primary spermatocyte (2n)

   • spermatogonia = true stem cell

   • make 2 daughter cells (each w 46 chromosomes)

     • 1st = cont as spermatogonia

     • 2nd = primary spermatocyte

1. primary spermatocyte cross tight junction

   • move outer → inner seminiferious tubles

   • tight junctions = protect & seperate envrio to help sperm mature

2. primary spermatocyte divide w meiosis I → 2 secondary spermatocytes (n)

   1. each 2nd spermatocyte = 2 copies of 23 chromosomes (sister chromatids together)

3. each 2nd spermatocyte divide w meosis II → 2 early spermatids (n)

   1. each spermatid = 1 copy 23 chromosomes (1 chromatid each)

• then move onto spermiogenesis

What is spermiogenesis?

• maturating & physical changes of spermatids to mature sperm (spermatozoa)

SPERMIogenesis process

• post spermatogenesis

• take 64-72 days

1. early spermatid → spermatozoa (n)

   • exit intercellualr space → lumen of semiinferous tubues by sertoli cells

   • spermatozoa = late spermatid

2. spermatozoa travel thru seminiferous tubules → epididymus → mature as mature sperm

   • change shape → shed cytosl & grow tail

   • cont. mature as move & settle in epididymis

What are spermatocytes/spermatogonium?

• True stem cells

• make 1 spermatogonia + 1 primary spermatocyte when differentiate

What is the progression of sperm during spermiogenesis?

Early spermatid --> late spermatid --> residual bodies + spermatozoa in lumen --> mature sperm in epididymis

What are the five parts of a mature sperm?

1. head → nucleus + 23 VV condensed chromosomes to deliver to oocyte 4 fertilization

2. acrosome → speclalized organelle w enzymes help penetrat oocyte 4 fertilization

3. midpiece → has mitocondrial sprial

4. mitochondrial spiral → mito dense pack 4 E move tail

5. tail → sperm propel itslef to oocyte

mt ham

what is the hormonal control and regulation of the male reproductive system?

1. teste f(x) based on FSH + LH

   • CAUSE → anterior pituitary release FSH & LH to respond to GnRH from hypothalamus

     • connect via hypothalamic hypophysioal protal system

   • hormones travel to testes

2. FSH act on sertoli cells → spermatogenesis occur + make inhibin

3. Inhibin feedback anterior pituitary → DEC FSH +LH 

4. LH stimulates leydig cells & make testosterone

5. testosterone → feedback to brain + help spermatogenesis

   • hypothalams (-) feedback = DEC GnRH

   • anterior pituitary (-) feedback = DEC FSH +LH

6. THUS → DEC inhibin & T lvls = release inhibitory effect & INC GnRH + FSH + LH

testosterone

• main M hormone → made inleydig cells from LH stimulation

• F → make in adrenal glands (muscle form, blood pxdtn, etc.)

PXDTN: cholesterol → diff intermediates → testerone

testerone functions

• diff impacts on each person

S3XUAL

• sex drive in puberty

• spermatogenesis

• dvlp male rpxdtn tract + external in dvlping baby

• grow & dvlp male rpxdtn organs in puberty

• 2nd s3x characterstics → muscle, hair face & genitals, deepr voice

NON S3XUAL

• bone & skeletal muscle growth

• INC aggressive

how does testerone levels change through life?

(1) fertilization

• INC during dvlp 4 rpxdtn tract & external genitals

(2) birth

• slight DEC w/o reason

(3) puberty

• GnRH lvl INC = INC FSH & LH = T INC = final mature rpxdtn system & mature sperm

• peak 16-18

(4) adult

• same lvls till 40 & slow DEC testerone

• 50 → andropause start + DEC sex desire, DEC erectile f(x), tired, DP, DEC lean body mass, INC obese, DEC bone density

What is andropause?

period where sperm production DEC (50+)

biological female reproductive system

• ovary → site dvlp F gamete oocyte

  • respond to FSH & LH

  • secrete estrogen & progesterone

  • release oocyte during ovulation

• fimbrea → catch oocyte post release by ovary w ovulation

  • finger like projection sweep into uterine tube

• uterine/fallopian tube → sperm & oocyte meet & fertilize

  • cilia move oocyte/embryo → uterus

  • uterine tube mve = progesterone reg little

• uterus → muscle organ 4 pregnancy

  • normal embryo implant into endometrium

  • endometrium dvlpmt = estrogen reg

  • endometrium mature = progesterone reg

• cervix → connect vaginal canal + uterus

  • secrete mucus → vary type & thickness

• vagina → get penis/sperm, discharge fluid, birth canal

When does the oocyte reservoir develop and how does it change over the life course?

• oocyte YOU come from when bio MOM in bio GRANNY womb

• oocyte # peak in fetal dvlp & DEC till X @ menopause

• THUS → ovary stockpile when born so have enough & healthy oocyte 4 rpxdtn

• oocyte X replace self & DEC til menopause

how do oocytes do meiosis?

1. normal meosis during fetal dvlp → prophase 1 (germinal vesicle stage)

   • only pair up homologus chromosomes

   • reg prophase 1 → crossing over happen & homologous chromosomes exchange genetic material to INC genetic diversity

2. puberty restart meiosis → metaphase 2

   • puberty = hormal signals trigger oocyte recruitment 4 mature w each cycle

     • X recruit = dormant till recruit OR die

     • recruited = meiosis cont till metaphase 2

       • asymmertical cytokenesis →

         • (1) 1 large oocyte

         • (2) smaller polar bodies w excess hormones → X fertilize

         • metaphase 2 = sister chromatids seperated BUT finish post fertilization

3. fertilization restart & finish meosis

   • fertilization trigger meiosis 2 finish

   • fertilization = symmetrical cytokinesis & oocyte expel another polar body → be haploid cell

   • sperm DNA + oocyte DNA = zygote & start embryonic dvlpt

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• dvlp oocyte & meiotic process start BEFORE birth

• blocked till puberty most & some till menopause

• meiotic process cont w ovulation (1 dom oocyte suround w cumulus cell complex)

• meiotic process finish when fertilization occur

At birth what stage are most oocytes blocked at?

Diplotene stage of prophase I

spermatogenesis VS oogenesis

O →

• makes follicle

• supported w granulosa cell

• start @ gestation

• makes only 1 viable gamete

• blocked MOSTLY @ prophase 1

• finish meiosis when fertilize

S →

• supported w sertoli cells

• makes 4 viable gametes

• start @ pubety & true stem cell w mitosis

• finish meosis before fertilize

oocyte

immature egg cell

What is folliculogenesis?

• GOAL → get ready 4 F fertility

• RESULT → 1 haploid germ cell

• F(x)→

  • get dvlping folliclies from resting primordial pool

  • grow follicle wall w INC granulosa + theca cell layers

  • select & grow 1 mature graffian preovulatory follicle

• REGULATE → hypothalamic-pituitary-gonadal axis

  • 1. GnRH released from hypothalamus

  • 2. release FSH & LH anterior pituitary

  • 3. travel to ovaries & regulate gametogensis

what are the steps of folliculogenesis

(1) primordial follicle

• start w folliciles made in fetal (dormant till puberty)

  • born w all primodiral follicle one needs

• follicles = 1 oocyte + 1 layer flat granulosa cell

(2) primary follicle

• during puberty follicle activated

• go primordial → primary follicle (30-50)

  • 1 oocyte = ovulated

  • rest = atresia

• granulosa cell proliferate → VV layers around oocyte

• NEW → zona pellcida

(3) secondary follicles

• primary follicile mature → 2nd follicile

• granulosa cells cont proliferate & make hormones

• still 1 oocyte + zona pellcida

• NEW → theca cells & make hormones

(4) tertiary/antral follicles

• 2nd follicile → 3rd follicle

• granulosa cells cont proliferate = follciles grow big

• still 1 oocyte + zona pellucida + theca cells

• NEW → antrum (fluid filled cavity) help follcile swell 4 ovulation

• NEW → 2nd oocyte + polar body & ready for ovulation if matured enough

(5) pre ovulatory follicle

• 3rd follcile mature & antrum INC size → folliciles ready to release oocyte 4 ovulation

(6) ovulation

• if enough hormone made & stim ovulation = rupture follcile

• THEN → 2nd oocyte release in uterine tube 4 fertilization + granulosa cells around oocyte leave

• still have granulos & theca cells left

(7) corpus lutenum forms

• left over follicle cells → corpus luteum

• secrete hormones 4 pregnancy

• X pregnancy = degrate as corpus albican (scar tissue)

Primordial follicle → primary follicle → secondary follicle → tertiary follicle → pre-ovulatory follicle → ovulation → corpus luteum → corpus albican

What is oogenesis?

oocyte development → only egg/oocyte itself

What is the zone pellucida?

gelatinous layer made during oogenesis

• btwn oocyte & cells of the follicle

What are granulosa cells?

nurse cells → help mature, care & maintain oocyte

secrete estrogen

What are theca cells?

nurse cells → help mature, care & maintain oocyte

secrete progesterone

atresia

follicle degrates

What occurs during ovulation?

• follicle rupture → release mature oocyte into uterine tube

• REG → hypothalamic-pituitary-ovarian axis

• CAUSE → surge LH

hypothalamic-pituitary-gonadal axis (HPG)

• regulate menstural cycle

  • (1) folliculogenesis → grow & mature ovarian follecules 4 ovulation

  • (2) endometrial change → thick & prep uterine lining 4 implantation

ACTION→ comm. w hypothalamus, putlairy gland & ovaries w each cycle

GOAL → help egg mature + release & prep uterus 4 preggy

How do hormones from the hypothalamic-pituitary-gonadal axis (HPG) affect folliculogenesis?

(1) hypothalamus release GnRH (gonadotropin-releasing hormone)

• GnRH in pulses → travel to anterior pituitary via hypothalamic-hypopheseal portal system

• pulse frequency = control FSH & LH release (change w cycle phase)

(2) pituitary release FSH + LH

(3) ovaries make estrogen + progesterone

• growing follicles release estrogen

• post ovulation empty folliclle → corpus luteum & secretes progesterone

(4) (-) feedback loops reg cycle

• INC estrogen & progesterone = inhibit FSH & LH @ hypothalamus & pituitary

• THUS → X 1+ ovulations

(5) estrogen (+) feedback loop on LH

• right before ovulation, swtich (+) loop to ensure ovulation right time

• ACTION →

  1. dom follicle mature = INC lvl estrogen made

  2. estrogen reach critical threshold (12-14th day cycle) = stim hypothalamus & pituitary w dff neurons

  3. (+) feedback = rapid INC LH & little FSH INC

  4. LH surge = ovulation = egg release from follicle

  5. post ovulation = estrogen DEC = progesterone in corpus luteum go (-) loop = DEC LH

(6) X preggy

• corpus lutem break = DEC progesterone & estrogen = mensutration (endometrial lining shed

• cycle restart → hypothalamus release GnRH

follicle stimulating hormone (FSH)

• LOCATE → gonadotrophs in anterior pituitary

• stim folliculogenesis = grow ovarian follicles w 1 dominant follicle

• dom follicle make estrogen

LH

• LOCATE → gonadotrophs in anterior pituitary

• work w/ FSH to mature dominant follicle

• surge LH = ovulation

estrogen

• relese by growing follicle

• USE →

  • (1) stim thickening of endometrial lining 4 implantation

  • give feedback to brain (reg FSH + LH lvl)

progesterone

• hormone released by corpus luteum

• USE → stabilize endometrial lining 4 fertlized egg implant

How are FSH and LH regulated normally?

via (-) feedback loop by estrogen

• INC estrogen & progesterone = inhibit FSH & LH @ hypothalamus & pituitary

How is LH regulated just before ovulation?

(+) feedback loop caused by estrogen = surge in LH = ovulation

How does the positive feedback loop work?

1. Dominant follicle matures

2. high levels of estrogen produced

3. estrogen reaches critical level

4. acts on different neurons with a positive effect

5. stimulates the hypothalamus and pituitary

6. surge in LH & little FSH

7. ovualtion trigger

8. egg release from follicle

how do the e pituitary hormones affect the cells of the follicle/gonadotropin?

• thecha cells = LH hormone receptors

  • response w convert cholesterol → androgen precusor (testerone)

  • testerone qickly move to granulosa cell

• granulosa cells = FSH hormone receptors

  • use aromataste/Cyp19 convert testerone → estrogen

  • THEN → follicle make INC estrogen to stim LH surge

how are the stages of the female reproductive cycle regulated by hormones?

1. follicular phase

   • many primodial follicules recruited & some dvlp occur (b/c ovarian signalling)

   • follicles start making LH & FSH receptors → dom follicule expressing MOST FSH selected to progress

2. ovulation

   • egg released from follicule

   • new recruitment of diff folicules start → bc ovarian stimulation

   • near ovulation = granulosa cells INC LH receptor & lose FSH receptors

3. luteal phase

   • post ovlation = granulosa & theca cells be corpus luteum

     • THUS → only LH receptors

     • LH receptors control process cholesterol → progesterone sent in blood + some → estrodiol (help hypothalamic pitutitary gonatroppin axis)

   • THEN → degrate into corpus albicans

   • new recruitment of diff folicules start → bc ovarian stimulatioin

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ovarian hormones → make by follicle cells (granulosa + theca)

• estrogen made

  • main (-) inhibt effect → DEC FSH & LH

  • some (+) effect → INC estrogen enough signal release LH w 1 dom follicle selected

• progesterone INC post ovulation

how do hormones affect the uterine lining?

based on estrogen & progesterone lvls

(1) proliferation phase

• follicular phase when follcile dvlp + INC estrogen

  • follicule changes in ovary w granulasa & techa cells

• estrongen = stim uterus make INC endometrium to prep implantation

• INC estrogen till LH surge

(2) secretory phase

• post ovulation = INC progesterone (corpus luteum)

• progesterone mature endomatrium → help dvlp vasculature & endometrium dvlp right thickness to get proper implanation

(3) menses

• X pregnancy = progsterone lvl DEC = X endometrium

if pregnant = INC progesterone lvl b/c embryo makes hormone maintain corpus luteum

menstrual cycle

1. follicular phase

   • @start = DEC estrogen & progesterone

     • THUS → top of uterus lining shed & menstural bleeding

   • pituitary gland send FSH to ovaries→ stim dvlp range of follicules

     • each follicule w immaure egg & estrogen

     • 1 dom follicule dvlp → INC estrogen = inhibit FSH (smaller follicile die)

     • INC estrogen = thicken endometrium lining

2. ovulation phase

   • INC in LH & FSH hormones → surge LH = ovulation w egg release

   • egg move into fallopian tube → uterus

   • 16-32 hrs post surge (day 14)

3. luteal phase

   • LH & FSH DEC = make corpus luteum

   • corpus luteum make estrogen & progesterone = thicken endometrium lining

   • fertlizied = progeserone support

   • X fertilized = corpus lutem break = DEC progesterone & estrogen & mensus

combined birth control pills

• synthetic estrogen & progestone

  • estrogen alone = carcinogenic

• missing dose = hormone lvl DEC = ovulate & preggy

• F(x) → take 21 days, 7 day placebo & mensus

  • 7 day placebo to follow natural hormone cycle

• GOAL →

  • suppress ovulation & prevent implantation

  • keep constant stable lvl hormones = override natural cycle

• ACTION → stable mid estrogen & progestin lvl 4

  • (1) estrogen (-) loop to hypothalmus & pituitary

    • THUS → X LH surge = X ovulation

  • (2) progestin → thicken cervical mucus (hard sperm reach egg) & thin endometrial line (DEC implant)

menopause

• nautral DEC rxpdtn hormones w ovaries

• 45-55 yrs

• RESULT → end ovulation & menstural cycle

causes for menopause

1. DEC ovary follicules

   • born limited # follicles → most lost w ovulation & atresia

   • menopause hit = X functional follicles left

2. DEC estrogen & progesterone

   • DEC follicles = DEC estrogen

   • X estrogen = X LH = X ovulation = X progesterone from corpus luteum

3. FSH & LH X respond

   • DEC estrogen = X (-) loop = pituitary release INC FSH & LH

   • BUT X response bc → X functional follicles left + ovarian cells X sensitive signals

effect of menopause on hypothalamic-pituitary-gonadal (HPG) axis

GnRH → cont release hypothalamus, DEC effective w X response to stim from ovaries

FSH → INC lots, try stim ovaries w/o response bc X follicules

LH → INC lots, X ovulation

estrogen → DEC = hot flash, mood change, bone loss

progesterone → DEC, X corpus luteum w/o ovulation

physical effects of menopause

• hot flast & night sweat → hypothalamus X good T reg

• irregular & X period → X ovulation & irregular cycle till stop

• osteoporosis risk → DEC estrogen = DEC bone density help = INC fracture risk

• mood change & sleep issues → estrogen affect ntm 4 mood & sleep

• vag dry & skin change → DEC estrogen = DEC elasticity = thin & dry