reproduction notes.docx

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REPRODUCTION NOTES

LECTURE ONE (MALE REPRODUCTION):

1. List the hormones that are secreted by the testis Testosterone (Leydig cells), inhiin (!ertoli cells)

2. Describe how secretion o the testic!"ar hormones is re#!"ated T secretion y Leydig cells decre"ses #nR$ (hy%oth"l"&'s) "nd L$

("nterior %it'it"ry), Inhiin ro& !ertloi cells decre"ses !$$. Describe the ro"e o the hy%otha"am!s and %it!itary #"and in

the re#!"ation o s%ermato#enesis&. Describe the ro"e o the hy%otha"am!s and %it!itary #"and in

the re#!"ation o testic!"ar steroido#enesis '. List se(era" ca!ses o ma"e inerti"ity*"secto&y, 'n+non c"'ses, %"st cry%torchidis&

• -"s deerens connects e%ididy&is thro'gh to the %rostr"te gl"nd. Testis isthe site o s%er&"togenesis.

• Prostr"te gl"nd sits 'nder the l"dder, "llos s%er& to tr"*el thro'gh *"s

deerens "nd %ic+ '% secretions &"de y the %rostr"te.

• The se&in"l *esicles "nd %rostr"te gl"nd &"+e '% the secretions re/'ired

or the s%er& cells to s'r*i*e "ter e0"c'l"tion. They "re +non "s the

"ccessory gl"nds.

• !te%s o se1'"l di2erenti"tion:

3 The "sence o !R4 "nd TD (sign"ling &ech"nis&s) c"'ses the

or&"tion o o*"ries. The !R4 "nd TD &ech"nis&s sign"l the

or&"tion o testes.3 The e&"le re%rod'cti*e syste& is the %"ssi*e or de"'lt di2erenti"tion

%"th"y or syste&. The &"le re%rod'cti*e syste& is "n "cti*e syste&

"nd re/'ires its on sign"ling &ech"nis&s hich "re the !R4 "nd TD

&ech"nis&s.



3 I there is " %role& in the "cti*"tion c"sc"de or sign"ling &ech"nis&s,

there &"y e %role&s in the or&"tion o testes, thereore " %role&

in testosterone hich &"y c"'se %resence o e&"le tr"its des%ite

eing &"le "nd h"*ing 54 chro&oso&es.

• De*elo%&ent o e1tern"l #ent"li":3 M"le "nd e&"le genit"li" loo+s identic"l "t 6 ee+s o gest"tion.3 At 78 ee+s, di*ergence occ'rs "nd there is " di2erence in olding.3 Ne"r the end o gest"tion, "ct'"l di2erences c"n e oser*ed, d'e to

the sign"ling c"sc"de eing "cti*"ted in the &"les.

• De*elo%&ent o the re%rod'cti*e tr"ct:3 At 6 ee+s, identic"l str'ct'res "re %resent. There is the %resence o

i%otenti"l gl"nd, ol9"n d'cts "nd &'lleri"n d'cts.3 !R4 "cti*"tion "nd testosterone sign"lling, "long ith &'lleri"n

inhiition "ctor c"'ses de*elo%&ent o &"le re%rod'cti*e syste&.3 Asence o sign"ls c"'se the or&"tion o o*"ries "nd th's the

de*elo%&ent o the e&"le re%rod'cti*e syste&.3 The &"in di2erence in the str'ct'res o the &"le "nd e&"le

re%rod'cti*e syste& is the %resence o se&in"l *esicles "nd %rostr"te

gl"nd in the &"les "nd the %resence o 'ter's in e&"les. Testes "nd

o*"ries "re si&il"r str'ct'res, "s "re the *"s deerens "nd "llo%i"n

t'es.

• Testes:3 !it inside the scrot'&, "s they "re *ery sensiti*e to the ody

te&%er"t're (ill sto% 'nctioning in ody te&%er"t're).3 ell %rotected ithin l"yers o &'scles "nd lood *essels "s it is the

site o testosterone "nd s%er& %rod'ction.

3 Cont"ins coiled se&iniero's t''les here s%er& is %rod'ced, it is9ltered thro'gh the Rete testes then tr"ns%orted to the t"il o the

e%ididy&is. here they "re &"t'red "nd stored 'ntil e0"c'l"tion.

• The testes h"s to co&%"rt&ents, the s%er& %rod'cing co&%"rt&ent

hich cont"ins se&iniero's t''les "nd the sertoli cells (th"t %rod'ce

inhiin) "nd the "ndrogen %rod'cing co&%"rt&ent, hich cont"ins the

interstiti"l co&%"rt&ent "nd the leydig cells (hich %rod'ce testosterone).

They "re oth controlled y the $P# "1is.

• Testosterone %rod'ction:3 Leydig cells %resent in eteen se&iniero's t''les %rod'ce

testosterone.

3 Testosterone is " steroid hor&one i&%ort"nt or s%er&"togenesis. Its%rod'ctionis controlled y L$.3 C"str"ted %eo%le &"+e little testosterone.3 le*els o testosterone do not ;'ct'"te to " gre"t le*el d'ring " &"le<s

lie cycle, "s o%%osed to the e&"le steroid hor&ones, hich decre"se

in le*els "s yo' ne"r &eno%"'se.3 L$ inds to rece%tors on Leydig cell Leydig cell.3 This sti&'l"tes rele"se o "denyl cycl"se hich egins " c"sc"de o

re"ctions to sti&'l"te %rod'ction o cAMP.3 cAMP "cti*"tes %rotein +in"se, hich in t'rn, "cti*"tes s%eci9c

en=y&es o %rod'ce testosterone.3 !econd &essenger > cAMP, sti&'l"tes synthesis o Testosterone ro&

cholesterol.



3 Testosterone is secreted into the %l"s&" here it is tr"ns%orted o'nd

(?@) to se13inding glo'lin

• $or&on"l reg'l"tion o testic'l"r co&%"rt&ents:

33 #nR$ %rod'ced in the hy%oth"l"&'s. L$ "nd !$ "re %rod'ced in the

"nterior %it'it"ry gl"nd.3 I too &'ch testosterone is %rod'ced, there is " neg"ti*e eed"c+ ro&

the leydig cells to the r"in.3 E1cess testosterone c"'ses neg"ti*e eed"c+ to oth "nterior

%it'it"ry gl"nd "nd the hy%oth"l"&'s.3 Inhiin c"'ses neg"ti*e eed"c+ to only "nterior %it'it"ry gl"nd.

• Reg'l"tion o s%er&"togenesis "nd testosterone %rod'ction:3 #nR$ is rele"sed in %'lses ro& the hy%oth"l"&'s.3 #nR$ sti&'l"tes secretin o !$ "nd L$, ro& the sertoli cells "nd the

leydig cells res%ecti*ely.3 !$ c"'ses secretion o inhiin hile L$ c"'ses secretion o

testosterone.3 Testosterone "nd inhiin "re neg"ti*e eed"c+ reg'l"tors o #nR$ "nd

the gon"dotro%ins.3 !$ "nd high le*els o testosterone "re re/'ired or s%er&"togenesis.

• 'nction o Testosterone:3 Beore irth: Re/'ired or the de*elo%&ent o M"le e1tern"l genit"li",

M"le re%rod'cti*e tr"ct, Descent o testes into scrot'& (&"y c"'se

inertility otherise)3 Ater irth: Testosterone secretion ce"ses, testes re&"inder o

re%rod'cti*e syste& re&"in s&"ll non'nction"l 'ntil %'erty.



3 D'ring P'erty: Testosterone secretion s'rges, Testes enl"rge

s%er&"togenesis egins, Penis scrot'& enl"rge, Accessory secretory

gl"nds enl"rge egin secreting.

• Action o Testosterone:3 Androgenic "ctions: Initi"tion "nd &"inten"nce o s%er&"togenesis:

M"inten"nce o second"ry se1'"l ch"r"cteristics: This is "chie*ed

*i" the con*ersion o testosterone to D$T. Testosterone c"n "lso e

con*erted to estrogen y "ro&"t"se hich is o'nd &"inly in "di%ose

tiss'e.3 An"olic "ctions: Testosterone incre"ses "s"l &et"olic r"te "nd the

r"te o %rotein synthesis. Incre"ses &'scle &"ss. Incre"ses RBC.

• T"rget org"ns o testosterone:3 In &"les: %rostr"te "nd testes.

3 In e&"les: re"st "nd 'ter's3 In oth: r"in. $e"rt, li*er "nd ones.

• E2ects o testosterone: incl'de "cne, enl"rge&ent o l"ryn1, "ci"l h"ir,

&'scle 'l+, de%osition o "t on t'&&y inste"d o hi%s in &"les,

enl"rge&ent o %enis, scrot'& "nd %rostr"te., incre"se in one strength

"nd incre"se in height.

• !e&iniero's t''les:

3 !ite o s%er&"togenesis



3 !ti&'l"ted "nd reg'l"ted y gon"dotro%ins "nterior %it'it"ry

hor&ones.3 Initi"l de*elo%&ent in*ol*es s%er&"togoni" th"t "re loc"ted in the

"se&ent &e&r"ne.3 !ertoli cells "re the n'rsing cells th"t %ro*ide the no'rish&ent.

3 This is olloed y s%er&iogenesis.

• !%er&iogenesis ( de*elo%&ent o s%er&"to=o" ):

3 Ch"nge in sh"%e ro& ro'nd sh"%e to recogni=ed sh"%e ith " t"il.



3 Mo*es to t"il o e%ididy&is here they &"t're this t"+es "ro'nd 7F to

F7 d"ys "nd &"t're s%er& cells c"n re&"in ertile or "o't " &onth.3 The to testes o " h'&"n "d'lt %rod'ce G7F8 3 F88 &illion s%er&

e"ch d"y.

• The !ertoli cells:

3 Prod'ces inhiin, hich h"s endocrine "cti*ity > eeds "c+ to the%it'it"ry "nd hy%oth"l"&'s to ↓ !$ secretionH h"s %"r"crine "cti*ity

ithin the testis, on the Leydig cellsH "ndrogen inding %rotein >

%ro*ides "n "ndrogen rich en*iron&ent ithin the t''lesH con*erts

testosterone to estr"diol.

• Blood3 testes "rrier:3 !ertoli cell is i&%ort"nt or the de*elo%&ent o s%er&"to=o"3 or&"tion o tight 0'nctions y "d0oining !ertoli cells cre"tes " se%"r"te

l'&in"l co&%"rt&ent ithin the se&iniero's t''les (BLOOD TE!TI!

BARRIER)3 The tight 0'nctions or& "nd re3or& to "llo s%er&"togoni" to &igr"te

into the l'&in"l co&%"rt&ent.3 !ertoli cell secretes testic'l"r ;'id hich c"rries the s%er&"to=o" to

the e%ididy&is here they &"t're "nd g"in &otility

• E%ididy&is:3 The e%ididy&is s'rro'nds the %osterior edge o the testes "nd is "

series o coiled t'es hich &onitor "d0'st co&%osition o ;'id

%rod'ced y the se&iniero's t''les, "cts "s " recycling centre or

d"&"ged s%er&, stores "nd %rotects s%er&"to=o" hile "cilit"ting

'nction"l &"t'r"tion.3 !%er& "rri*e "s i&&"t're, non3&otile s%er&"to=o". They t"+e

"%%ro1i&"tely 7F3F8 d"ys to &o*e thro'gh the e%ididy&is, "ter hich

ti&e, they "re c"%"le o si&&ing3 I&&"t're s%er& "re stored in the t"il o the e%ididy&is or se*er"l

&onths.3 !%er& "re e0"c'l"ted ro& the e%ididy&is into the d'ct's deerens.

• 'nction o "ccessory gl"nds:

3 !ecretions o the %rost"te (8), se&in"l *esicles (J8) "nd 'lo3

'rethr"l gl"nd together ith the ;'id secreted y the sertoli cells "nde%ididy&is (78) &"+e '% the se&en.

3 The 'lo'rethr"l gl"nd secretions "ct "s " cle"nsing l'ric"nt.3 !e&in"l *esicles %ro*ide r'ctose, citric "cid, %rost"gl"ndins "nd

9rinogen. These %ro*ide n'trients or the s%er&.3 Al+"line %rost"tic ;'id hel%s to %ro*ide " ne'tr"l %$ or ertili="tion.

• -"secto&y ( &"le contr"ce%tion):

3 -"s deerens "re c't "nd the ends "re tied3 Pre*ents s%er& ro& entering the e0"c'l"te > sterile se&en3 Does not "2ect %rod'ction o testosterone, so erection "nd e0"c'l"tion

"re nor&"l

3 Ao't @8 o &en de*elo% "ntiodies to s%er& hich c"'ses ertility%role&s i the *"secto&y is re*ersed.



• M"le inertility:3 Ao't 7:F8 &en "re s'ertile3 In "o't J8 o the c"ses, no identi9"le c"'se is recognised3 @8 I- tre"t&ents "re done or &"le "ctor inertility. Uses

intr"cyto%l"s&ic s%er& in0ection IC!I

3 !'ccess'l %regn"ncy no "chie*"le in co'%les ho %re*io'sly h"d no%ros%ect o ertility → decline in donor inse&in"tion.

• C"'ses o &"le inertility:

• Pri&"ry (G78.K):3 D'e to "il're ithin testis > either o se&iniero's t''les or Leydig

cells > lo testosterone "nd high L$ "nd !$.3 lineelter<s !yndro&e (554 G7.?)3 P"st Cry%torchidis& (GJ.K) ('ndescended testes)3 P"st M'&%s Orchitis (G7.J)3 P"st irr"di"tion or cytoto1ics (G8.@)

• !econd"ry (G8.J):

3 D'e to "il're o %it'it"ry or hy%oth"l"&'s> lo gon"dotro%hins (L$ "nd !$) "nd lo testosterone.

• Other:3 #enit"l Tr"ct Ostr'ction (GK.7)3 -"ricocoele (GK8)3 Idio%"thic (G?.)

LECTURE TO (EMALE REPRODUCTION 7):

1. Describe the str!ct!re and !nction o the ema"e re%rod!cti(e

or#ans

2. E)%"ain the com%"ete o(arian and !terine cyc"es



$. Understand the hormona" mechanisms that re#!"ate ema"e

re%rod!cti(e !nctions

e&"le re%rod'cti*e syste& is &ore co&%le1 co&%"red to &"le

re%rod'cti*e syste& ec"'se they %rod'ce "nd rele"se g"&etes, n'rt'rede*elo%ing et's "nd gi*e irth.

Intern"l gent"li":

* The e&"le d'ct syste& is &"de '% o the *"gin", 'ter's "nd

'terine"llo%i"n t'es "nd they %ro*ide " %"ss"ge"y or conce%tion

"nd irth.* Unli+e the &"le syste&, the e&"le d'ct syste& is not contin'o's,

there is " g"% eteen the o*"ries "nd the "llo%i"n t'es.* The eggs "re rele"sed into the o*"ries "nd s'c+ed into the "llo%i"n

t'e y the 9&r"e.* !o&e oocytes don<t &"n"ge to &"+e it into the t'e "nd "re lost in

the %eritone"l c"*ity.

* !o&e eggs &"y get lost "nd res'lt in ecto %regn"ncy (o'tside the'ter's).

The *"gin":

* %ro*ides " %"ss"ge"y to eli&in"te &enstr'"l ;'ids, recei*e the %enis

d'ring interco'rse, e1%el et's d'ring child irth.* It is " thin "lled t'e, 378c& long* Both &'sc'l"r (s&ooth &'scle) "nd el"stic* Acidic en*iron&ent hel%s +ee% the *"gin" ree o inection 't &"+es it

hostile to s%er&. Interestingly, teen"gers h"*e not de*elo%ed "n "cidic

en*iron&ent, &"+ing the& &ore s'sce%tile to !TDs.



• The cer*i1 is the o%ening o the otto& o the 'ter's. It needs to o%en to

e1%el "ies.

• The 'ter's:3 $ollo, thic+ &'sc'l"r org"n th"t recei*es, ret"ins "nd no'rishes

o2s%ring

3 Consists o the ody (&"0or region), 'nd's (to% region) "nd cer*i1(0oins to the *"gin")

3 #l"nds in the &'cos" o the cer*i1 secrete &'co's th"t loc+ s%re"d o

"cteri" into 'ter's ro& *"gin"3 Also loc+s entry o s%er& e1ce%t "t &idcycle hen &'co's eco&es

less *isco's.3 The 'terine "ll h"s l"yersH the Peri&etri'& (o'ter&ost l"yer),

Myo&etri'& ('l+y, &'sc'l"r &iddle l"yer, contr"cts to e1%el "y)

"nd the Endo&etri'& (&'cos"l inner l"yer hich "llos or

i&%l"nt"tion o the ertilised egg. This is the l"yer shed d'ring

&enstr'"tion. )

3 The endo&etri'& in t'rn h"s to l"yersH the 'nction"l l"yer(Undergoes cyclic ch"nges d'e to o*"ri"n hor&ones "nd is shed d'ring

&enstr'"tion) "nd the B"s"l l"yer (Unres%onsi*e to o*"ri"n hor&ones).

3

• The "llo%i"n t'es o*id'cts 'terine t'es:3 !ite o ertilis"tion.3 Recei*e o*'l"ted oocytes3 inger3li+e %ro0ections (9&ri"e) see% o*er the o*"ry to c"%t're the

oocyte



3 M'sc'l"r &o*e&ents "nd e"ting cili" c"rry the oocyte to"rds the

'ter's

• The o*"ry:3 F s&"ll, "l&ond sh"%ed org"ns th"t %rod'ce e&"le g"&etes (o*"

oocyteseggs) "nd secrete e&"le se1 hor&ones (estrogen "nd

%rogesterone)3 E"ch o*"ry consists o the Med'll" (Inside region hich is highly

*"sc'l"rised) "nd the Corte1 (O'tside region here ollicles "re

&"t'red to rele"se oocytes).

• The o*"ri"n cycle (e*ents th"t &"t're "n egg) ( h"s to %h"ses):3 ollic'l"r %h"se (d737K): ollicle groth. O*'l"tion occ'rs "t the end o

this st"ge3 L'te"l %h"se (d7@3F): %eriod o cor%'s l'te'& "cti*ity3 Dri*en y hor&ones rele"sed y the "nterior %it'it"ry gl"nd

(gon"dotro%ins).3 Only 78 o o&en h"*e " Fd cycle. Irres%ecti*e o cycle length,

l'te"l %h"se is nor&"lly 7Kd

• The ollic'l"r %h"se:

3 The %ri&ordi"l ollicle is &"de '% o " s&"ll oocyte s'rro'nded y "single l"yer o gr"n'los" cells.



3 The %ri&"ry ollicle is &"de '% o " 'lly gron oocyte s'rro'nded y

the =on" %ell'cid" "nd the single l"yer o gr"n'los" cells.3 The %re"ntr"l ollicle "nd the e"rly second"ry ollicle h"s the 'lly

gron oocyte s'rro'nded y l"yers o the gr"n'los" cells "nd " single

l"yer o the thec" cells

3 The e"rly "ntr"l ollicle or the l"te second"ry ollicle cont"ins the 'llygron oocyte s'rro'nded y the =on" %ell'cid", olloed y &'lti%le

l"yers o the gr"n'los" cells hich "lso cont"in " s&"ll "tri'& 9lled

ith ;'id. The gr"n'los" cells "re s'rro'nded y &'lti%le l"yers o the

thec" cells3 The #r""9"n or &"t're ollicle is si&il"r to e"rly "ntr"l cell, only the

"ntr'& is l"rger ith &ore ;'id, &ore thec"l cells "nd cont"ins

c'&'l's oo%horo's hich "re so&e g"n'los" cells connected to the

oocytes.

• O*'l"tion:3 The 'lging ollicle e*ent'"lly r'%t'res the "ll o the o*"ry "nd the

oocyte is rele"sed3 !o&e o&en c"n eel o*'l"tion "s " tinge o %"in3 A n'&er o ollicles "re eing %re%"red ithin the o*"ry "t "ny one

ti&e > not s're ho one ollicle is selected or o*'l"tion (r"tern"l tins

res'lt hen &ore th"n one is rele"sed)3 Incre"ses in L$ ("nd !$) sign"ls ti&e or o*'l"tion

• L'te"l %h"se:



3

• Cor%'s l'te'&:

3 M"de o l'teinised gr"n'los" "nd thec" cells.3 R"%id *"sc'l"ris"tion o l'te"l cells3 The CL %rod'ces Progesterone ("nd so&e oestrogen)3 M"inten"nce o the CL de%ends on L$ "nd, i %regn"nt, hC#3 I no %regn"ncy, CL regresses to eco&e " Cor%'s Alic"ns, hich is

the degr"ded CL. !to%s %rogesterone secretion.• The "tresi" %"th in*ol*es the oocytes "nd ollicles th"t ere not &"t'red

%ro%erly "nd their 'lti&"te degener"tion inside the o*"ries.

• Uterine &enstr'"l cycle:

3 Cyclic ch"nges o the endo&etri'& in res%onse to hor&onesH

endo&etri"l ch"nges "re coordin"ted ith the o*"ri"n cycle3 hile the o*"ri"n cycle is dri*en y hor&ones rele"sed y the "nterior

%it'it"ry, the 'terine cycle is dri*en y steroid hor&ones rele"sed y

the o*"ry.



• D"y 73@: Menstr'"l %h"se (&enses) >3 shedding o the 'nction"l l"yer o the endo&etri'&3 estrogen "nd %rogesterone "re lo

• D"y J37K: Prolier"ti*e (%re3o*'l"toryollic'l"r) %h"se 33 Re'ilding o the 'nction"l l"yer o the endo&etri'&3 Prolier"tion incre"se o gl"nd'l"r, stro&"l "nd *"sc'l"r endotheli"l

cells3 Thic+ening o cer*ic"l &'co's, eco&es less *isco's "nd stic+y to

"llo entry o s%er&

3 !ti&'l"ted "nd s'st"ined y o*"ri"n estrogens.3 O*'l"tion occ'rs "t the end o this %h"se* Under the in+!ence o estro#en.

D"y 7@3F: !ecretory (%ost3o*'l"tory) %h"se* Begins i&&edi"tely "ter o*'l"tion* Prolier"tion ce"ses* !ecretory "cti*ity o gl"nd'l"r cells incre"ses* Endo&etri'& %re%"res or i&%l"nt"tion (gl"nds enl"rge, "rteries

elong"te, n'tritio's glycogen is secreted)* !ti&'l"ted y %rogesterone "nd estrogens ro& cor%'s l'te'& > I

ertilis"tion does not occ'r, CL degener"tes. Lo %rogesterone le"ds to

s%"s& o "rteries, "nd lo o1ygen le*els

* Blood enters r"g&ented c"%ill"ries "nd &enses egins "g"in* ,aintained by %ro#esterone



LECTURE T$REE (EMALE REPRODUCTI-E !4!TEM F):

• #nR$ ( gon"dotro%hin rele"sing hor&ones):3 Also +non "s l'teinising hor&one3rele"sing hor&one (L$R$)3 Controls the re%rod'cti*e cycle

3 78 "&ino "cid %e%tide hy%o%hysiotro%hic hor&one3 Rele"sed ro& 7888<s ne'rons ithin the hy%oth"l"&'s in " %'ls"tile

&"nner3 Prod'ced in ne'rones in the r"in (%re3o%tic "re" "nd &edio"s"l

hy%oth"l"&'s)3 #nR$ ne'rones secrete #nR$ into hy%o%hysi"l %ort"l syste& in %'lses.3 The %'lses "re controlled y #nR$ %'lse gener"tor3 #nR$ %'lses sti&'l"te the synthesis "nd secretion o L$ "nd !$ ro&

the "nterior %it'it"ry

• !e1 steroids:3 Androgens, oestrogens "nd %rogestogens3 !teroid hor&ones (li%id sol'le)3 In e&"les, "ndrogens "re %rod'ced in the o*"ry y thec"l cells3 Androgens "re con*erted to estrogens in the o*"ry y gr"n'los" cells



3 The cor%'s l'te'& o the o*"ry %rod'ces %rogesterone3 !e1 steroids "re "lso %rod'ced y the corte1 o the "dren"l gl"nd3 !e1 steroids h"*e "ctions ithin the o*"ry "nd "re secreted into the

%eri%her"l circ'l"tion3 I&%ort"nt roles in " r"nge o re%rod'cti*e 'nctions incl'ding %rod'ction

o the g"&etes "nd eed"c+ "ctions on the re%rod'cti*e "1is3 In e&"les, oestrogens e1erts neg"ti*e or %ositi*e eed"c+ e2ects3 Progesterone e1erts only neg"ti*e eed"c+ e2ects

• #on"dotro%hins:3 Incl'des the L'teinising $or&one (L$) "nd ollicle !ti&'l"ting $or&one

(!$)3 $eterodi&eric %oly%e%tides (3s''nit "nd 3s''nit lin+ed y dis'lide

onds)3 3s''nit is co&&on to oth L$ "nd !$3 3s''nit is 'ni/'e "nd coners iologic"l s%eciicity3 #on"dotro%hins "re synthesised "nd stored in gon"dotro%h cells in the

"nterior %it'it"ry3 #on"dotro%hins "re secreted into the %eri%her"l circ'l"tion3 L$ secretion is %'ls"tile hile !$ secretion is not %'ls"tile (%"ssi*e)3 #on"dotro%hins "ct on the gon"ds to sti&'l"te the %rod'ction o the

g"&etes (s%er& in &"les "nd oocytes in e&"les) "nd to sti&'l"te the

%rod'ction o gon"d"l hor&ones s'ch "s the se1 steroids.

• Inhiins:3 #lyco%rotein hor&one3 In e&"les, inhiin is %rod'ced in the o*"ry y gr"n'los" cells3 The cor%'s l'te'& "lso %rod'ces inhiin3 Inhiin is secreted into the %eri%her"l circ'l"tion3 A2ects !$ secretion (eed"c+ "ctions on the re%rod'cti*e "1is.

Neg"ti*e eed"c+ "ctions on !$ secretion y direct "ctions "t the

"nterior %it'it"ry)3 Also in*ol*es "cti&ines3 Is o to ty%es: inhiin A "nd inhiin B (s"&e "l%h" s''nit, 't

di2erent et" s''nits)

• Reg'l"tion o hor&ones in the re%rod'cti*e "1is:

7) $y%oth"l"&'s3 %it'it"ry "1is (

LECTURE OUR (#AMETE!):

1. Understand the %rocesses in(o"(ed in %rod!ction o s%ermato-oa

2. Understand the %rocesses in(o"(ed in %rod!ction and mat!ration o

o(a

Mitosis: Cell Re%lic"tion



3 Nor&"l cell di*ision3 Mitosis is the n'cle"r di*ision in "ll non3g"&ete cells in hich the

n'&er o chro&oso&es is &"int"ined (ro& n to n)3 In*ol*es Inter%h"se, %ro%h"se, &et"%h"se, "n"%h"se, telo%h"se.

• Meiosis:

3 In*ol*es M"+ing g"&etes3 #"&ete (s%er&o*") or&"tion in*ol*es &eiosis3 Meiosis is the n'cle"r di*ision in the gon"ds in hich the n'&er o

chro&oso&es is h"l*ed (ro& Fn to n)3 To consec'ti*e cell di*isions (&eiosis I "nd II) olloing one ro'nd o

DNA re%lic"tion3 hen ertili="tion occ'rs, the nor&"l di%loid chro&oso&"l n'&er is

restored (in h'&"n , Fn KJ)3 Prod'ces o'r d"'ghter cells3 Introd'ces genetic *"ri"tion thro'gh r"ndo& "lign&ent (&'ddles '%

chro&oso&es ro& to di2erent %"rents) "nd crosso*er (s"%%ing o

chro&oso&"l sections)



• !%er&"togenesis:



3 > Occ'rs in the se&iniero's t''les3 > Prod'ces s%er&3 > !t"rts to occ'r "t "%%ro1i&"tely 7K ye"rs o "ge3 > Res'lts in K88 &illion ne s%er& %er d"y3 > Contin'es thro'gho't "d'lt lie > E"ch &"t're s%er& t"+es "o't 78

ee+s (JK d"ys) to &"+e

• !%er&"togoni" "re ste& cells.3 Mitosis %rod'ces " ste& cell (ty%e A) "nd " 't're s%er& (ty%e B)

3 Meiosis I occ'rs: > Pri&"ry s%er&"tocyte (Fn) → to second"ry

s%er&"tocytes (n)

3 Meiosis II occ'rs > E"ch second"ry s%er&"tocyte (n) → to s%er&"tids

(n).!%er&"tid "re s&"ll non&otile cells close to the l'&en o the t''le

3 !%er&"tids lose e1cess cyto%l"s& "nd or& " t"il, eco&ing

s%er&"to=o" (s%er&)

3

LECTURE I-E (ERTILI!ATION AND PRE#NANC4):

Describe the ste%s in(o"(ed in erti"isation

* At the ti&e o o*'l"tion, the o*'& is "rrested "t the &et"%h"se (M%h"se in cell cycle) Fnd &eiotic di*ision.



* Meiosis I is co&%leted y one oocyte e"ch &onth* C"lci'& rele"se "t ertilis"tion this hel%s in the co&%letion o the Fnd

&eiotic di*ision, only hen s%er& %enetr"tes.* The ste%s in*ol*ed "re:

7. !%er& e"*e thro'gh gr"n'los" cells

F. !%er& ind to =on" %ell'cid", c"'sing incre"sed c"lci'& le*els inthe s%er& > this le"ds to the re"+don o &e&r"nes ("croso&"l

re"ction). Acroso&"l en=y&es digest holes in the =on" %ell'cid"K. An "croso&"l %rocess is or&ed "t the ti% o the s%er&, "lloing it to

ind to rece%tors on the egg@. The s%er& "nd oocyte &e&r"nes 'se, rele"sing s%er& DNA into

eggJ. Entry o s%er& contents c"'ses incre"sed c"lci'& le*el in egg. This

triggers the cortic"l re"ction hich destroys s%er& rece%tors "nd

h"rdens the =on" %ell'cid". This loc+s %olys%er&y (egg dies ro& too &'ch DNA) Tins "re s%lit e&ryos or to eggs.

Pol"r odies ill 's'"lly 'ndergo "%o%tosis in "o't 76 to FK ho'rs "ter

the egg or&s (the 9n"l st"ges o telo%h"se II (cyto+inesis)) ec"'se they

h"*e rel"ti*ely little cyto%l"s& "nd sh'nted org"nelle de*elo%&ent.

E&ryonic De*elo%&ent: Qygote to l"stocyst

* As soon "s the oocyte is ertilised, it eco&es " -y#ote* The =ygote 'ndergoes contin'o's di*ision (F cells, K cells, cells etc) >

This occ'rs in the "sence o groth* Once the collection o cells e1ceeds 7J mor!"a

* The cells o the &or'l" contin'e to di*ide. A ;'id 9lled c"*ity or&s"nd the the =on" %ell'dic" (o'tside l"yer) st"rts to re"+ don or&ing

the b"astocyst. * The l"stocyst consists o "n inner cell &"ss, ;'id 9lled c"*ity "nd "

l"yer o tro%hol"st cells.

This is o""owed by im%"antation* The -y#ote/mor!"a/b"astocyst is ree ;o"ting "nd tr"*els don the

"llo%i"n t'e "nd into the 'ter's > No'rished y glycogen ithin

'ter's* I&%l"nt"tion o the b"astocyst occ'rs "o't J36 d"ys "ter ertilis"tion* Inte#rins on the tro%hob"ast ce""s "llo the l"stocyst to "tt"ch to

rece%tors in the endo&etri'&* I the endo&etri'& is not &"t're, the l"stocyst det"ches "nd ;o"ts to

" loer le*el o the 'ter's > tries to i&%l"nt "g"in

Tro%hol"st "dheres to site in the endo&etri'& ith &"t're rece%tors "nd

che&ic"l sign"ls

Tro%hol"sts %rolier"te "nd or& F l"yers

• 7. Cytotro%hol"st: inner l"yer o cells

• F. !yncytiotro%hol"st: cells in the o'ter l"yer lose their %l"s&"

&e&r"nes, in*"de "nd digest the endo&etri'&

'rther digestion occ'rs 'ntil the l"stocyst h"s 'ried itsel in the rich

endo&etri"l en*iron&ent. Endo&etri"l cells co*er l"stocyst or&ing se"l



I the im%"antation is s!ccess!"* M"t'r"tion t"+es J36 d"ys "nd s'ccess'l i&%l"nt"tion t"+es "nother @

d"ys ('s'"lly co&%lete y the 7Fth d"y "ter o*'l"tion)

* The e&ryo sign"ls to the cor%'s l'te'& to contin'e to %rod'ce%rogesterone "nd estrogen > %re*ents &enstr'"tion > This sign"lling

occ'rs *i" the h'&"n chorionic gon"dotro%in (hC#) hor&one* hC# le*els "re %resent in the &other<s lood one ee+ "ter

ertilis"tion "nd contin'e to rise 'ntil the end o the second &onth* Me"s're&ent o hC# le*els in 'rine is st"nd"rd %regn"ncy test

Describe the str!ct!re and !nctions o the %"acenta and amniotic

+!id* PL0CENT0* The h'&"n %l"cent" is discoid (i.e. ;"t, circ'l"r or&H dis+3sh"%ed),

eighs G@88 gr"&s "nd is he"*ily s'%%lied ith et"l "nd &"tern"llood *essels

* It is " te&%or"ry org"n th"t origin"tes ro& et"l "nd &"tern"l tiss'e* At irth %l"cent" eco&es se%"r"ted "nd is e1%elled h"r&lessly

des%ite eing highly *"sc'l"rised.* Pl"cent"l 'nctions:* 'nctions to tr"ns%ort eteen &'& "nd et's: > %ro*ides s'str"tes

or et"l &et"olis&3 "cts "s g't > dis%oses o "ste3 "cts "s +idney. >

E1ch"nges res%ir"tory g"ses3 "cts "s l'ng.* P"rti"l i&&'nologic"l "rrier (et"l genoty%e is oreign to &other)* Prod'ces hor&ones i&%ort"nt or %regn"ncy: %rogesterone, estrogens

"nd %rotein hor&ones (inc. hC#3h'&"n chorionic gon"dotro%hin)

* 0,NIOTIC LUID



* C'shions et's ro& tr"'&" "nd %ro*ides s%"ce to e1ercise groing

&'scles* Pre*ents 'ter's ro& co&%ressing the et's "nd "llos nor&"l l'ng

de*elo%&ent > "llos sy&&etric"l groth* M"int"ins const"nt te&%er"t're

* Pro*ides " ;'id reser*oir ro& hich the et's s"llos (sti&'l"tes g'tde*elo%&ent)* Consists &ostly o et"l 'rine ("lso l'ng li/'id, n"s"l secretions, s+in

cells etc) > 78&l "t + to 7L "t F +s3

Understand hormona" contro" o %re#nancy and materna"

ada%tations

> E&ryo sign"ls to the cor%'s l'te'& to contin'e to %rod'ce

%rogesterone "nd estrogen > -i" hC# hich is 'sed to detect %regn"ncy >

L"c+ o %rogesterone or estrogen sign"lling ind'ces &enstr'"tion >

Progesterone is then %rod'ced y %l"cent" to &"int"in %regn"ncy

*

* Progesterone is essenti"l or &"inten"nce o %regn"ncy3 +ee%s 'terine

&'scle /'iescent* Progesterone is %rod'ced y cor%'s l'te'& in 7st @8 d"ys, then ro&

%l"cent".

* Loss o Progesterone "ction ter&in"tes %regn"ncy3 eg Mie%ristone (orRU3KJ), " %rogesterone rece%tor loc+er.



* Medic"l "ortion 'sing &ie%ristone is the &ost e2ecti*e &ethod o

"ortion "t gest"tions o less th"n 6 ee+s.

Describe the hormona" contro" o "actation

* ♣ L"ct"tion c"n e di*ided into @ st"ges:* 7. ,ammo#enesis > De*elo%&ent o re"sts to 'nction"l st"te.* F. Lacto#enesis > !ynthesis "nd secretion o &il+ ro& the re"st

"l*eoli.* . a"acto3inesis > E0ection o &il+ o'tside the re"st.* K. a"acto%oiesis > M"inten"nce o l"ct"tion. @. In*ol'tion >

Regression "nd "tro%hy %ost l"ct"tion.* @. In(o"!tion > Regression "nd "tro%hy %ost l"ct"tion.

4hat ca!ses materna" ada%tations5

♣ M"ny o the &"tern"l "d"%t"tions "re dri*en y hor&on"l ch"nges d'ring

%regn"ncy

♣ $'&"n chorionic gon"dotro%in (hC#) > !ecreted y tro%hol"st cells, "nd then

%l"cent" > Pro&%ts cor%'s l'te'& to contin'e secretion o %rogesterone "nd

estrogen > hC# le*els rise 'ntil the end o the second &onth, then decline "s the%l"cent" egins to secrete %rogesterone "nd estrogen

♣ Progesterone "nd estrogen incre"se &ore sloly "t the st"rt o %regn"ncy 't

contin'e to incre"se thro'gho't gest"tion

♣ Morning sic+ness res'lts d'ring " ti&e hen the &"tern"l org"ns "re "d"%ting

to the incre"sed concentr"tions o circ'l"ting %rogesterone "nd estrogen.

LECTURE !I5 (PUBERT4):



1. Describe the sta#es o %!berty

* P'erty is the %rocess thro'gh hich " child &"t'res "nd eco&es c"%"le o

se1'"l re%rod'ction

3 Res'lt in the "tt"in&ent o second"ry se1'"l ch"r"cteristics "nd re%rod'cti*e

co&%etence

3 Inter"ction eteen #$ "nd gon"d"l steroids %rod'ces groth s%'rt "nd

"cti*"tion o re%rod'ction

6 Tanner Sta#es o %!berty 7,a"e8

T"nner I %re%'ert"l (testic *ol'&eS 7.@&l, s&"ll %enis c& or less 's'"lly S

?yo)

T"nner II testic'l"r *ol'&e eteen 7.J "nd J &lH s+in on scrot'& thins, reddens

"nd enl"rgesH %enis length 'nch"nged ?377yrs

T"nner III testic'l"r *ol'&e eteen J "nd 7F &lH scrot'& enl"rges 'rtherH %enisegins to lengthen to "o't J c& 7737F.@ yrs

T"nner I- testic'l"r *ol'&e eteen 7F "nd F8 &lH scrot'& enl"rges 'rther "nd

d"r+ensH %enis incre"ses in length to 78 c& "nd circ'&erence 7F.@37K yrs

T"nner - testic'l"r *ol'&e gre"ter th"n F8 &lH "d'lt scrot'& "nd %enis o 7@ c&

in length 7K

6 Tanner Sta#es o %!berty 7ema"e8

T"nner I no gl"nd'l"r tiss'e: "re"ol" ollos the s+in conto'rs o the chest(%re%'ert"l) ty%ic"lly "ge 78 "nd yo'ngerV

T"nner II Bre"st 'd or&s, ith s&"ll "re" o s'rro'nding gl"nd'l"r tiss'eH

"reol" egins to iden 78377.@V

T"nner III re"st egins to eco&e &ore ele*"ted, "nd e1tends eyond the

orders o the "reol", hich contin'es to iden 't re&"ins in conto'r ith

s'rro'nding re"st 77.@37V

T"nner I- incre"sed re"st si=e "nd ele*"tionH "reol" "nd %"%ill" or& "

second"ry &o'nd %ro0ecting ro& the conto'r o the s'rro'nding re"st 737@V

T"nner - re"st re"ches 9n"l "d'lt si=eH "reol" ret'rns to conto'r o the

s'rro'nding re"st, ith " %ro0ecting centr"l %"%ill". 7@V

2. Understand the hormona" chan#es that occ!r d!rin# %!berty 9

0drenarche and #onadarche

♣ Adren"rche: "cti*"tion o "dren"l "ndrogen secretion th"t egins in the %re3

%'ert"l %h"se

3 Adren"rche %recedes %'erty



3 An endocrine de*elo%&ent"l %rocess herey h'&"ns "nd select

nonh'&"n %ri&"tes incre"se "dren"l o't%'t o " series o steroids,

es%eci"lly D$EA "nd D$EA!.3 In h'&"ns ser'& le*els o D$EA! incre"se "t "ro'nd J3 ye"rs o "ge.3 This corres%onds ith the de*elo%&ent "nd e1%"nsion o the "dren"l

gl"nd.3 h"t triggers the onset o "dren"rche is 'n+non3 The %henoty%ic h"ll&"r+ o "dren"rche is "ndrogen3de%endent groth

o "1ill"ry "nd %'ic h"ir

♣ P'"rche: "%%e"r"nce o %'ic h"ir

♣ #on"d"rche: "cti*"tion o $P# "1is sign"lling, "ssoci"ted ith the %'ert"l

groth s%'rt "nd gon"d"l de*elo%&ent

3 The "cti*"tion o the o*"ry "nd testis "t the end o the %re%'ert"l

%h"se o de*elo%&ent "nd le"ds to the incre"se in gon"d"l steroid

%rod'ction "nd the co&%letion o g"&etogenesis.3 #on"d"rche is &"niest y re"st de*elo%&ent "nd &en"rche in girls,

"nd y testic'l"r enl"rge&ent "nd *irili="tion in oys.3 It is elie*ed th"t the hy%oth"l"&'s is "cti*"ted or rele"sed ro&

inhiition3 e do not +no h"t does this 3 c"ndid"tes incl'de: Nor"dren"line,

#ABA, W3endor%hin, NMDA, Do%"&ine, #roth "ctors, Le%tin3

♣ Thel"rche: "%%e"r"nce o re"st tiss'e

♣ Men"rche: onset o &enses

$. Understand the actors that contro" the timin# o %!berty

♣ Pri&"rily deter&ined genetic"lly (tins st'dies)

♣ Most signi9c"nt en*iron&ent"l "ctor 3 %ossily e1%l"ining "s &'ch "s F@ o

the *"ri"tion in the ti&ing o %'erty > is n'trition"l st"t's in childhood.

♣ E"rlier %'erty "ssoci"ted ith

> Childhood o*er n'trition "nd oesity

> Undereight children oten e1%erience del"yed %'erty

> $ighlights " Xcritc"l eight< theory

It is gener"lly "cce%ted th"t the decre"sing "ge o 9rst %eriod "nd the

onset o %'erty c"n e rel"ted to ch"nges in the n'trition"l st"t's o

children

• #nR$ P'lses Deter&ine P'erty ♣ Pre%'ert"l %eriod > Restr"int i&%osed

on %'ls"tile #nR$ rele"se d'ring childhood (F>78 ye"rs o "ge) > !$ "nd

L$ lo > Mini&"l to no ollic'l"rgenesis or s%er&"togenesis ♣ P'erty >



Incre"se in the %'lse re/'ency "nd "&%lit'de o #nR$ rele"se > Incre"se

in !$ "nd L$ %'lses > ollic'logenesis "nd s%er&"togenesis occ'r

LECTURE !E-EN:

18 To !nderstand what a trans#enic mo!se and how they are #enerated.

3 #enetic"lly &odi9ed Xengineered< &ice

3 irst genetic"lly &odi9ed "ni&"l y inserting " DNA *ir's into "n e"rly3st"ge

&o'se e&ryo

3 The inserted genes ere %resent in e*ery "d'lt cell

6 Ty%es o trans#enic a%%roaches:3 noc+3o't: insertion o " oreign se/'ence to disr'%t the gene to delete or

eli&in"te its 'nction (ho&o=ygote)

3 noc+3in: insertion o " %rotein encoding cDNA se/'ence > re%l"ces " gene ith

"nother, inste"d o deleting it.

2. To a%%reciate how trans#enic anima"s are !sed to mode" h!man

diseases

reproduction notes.docx

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