Reproduction and Development

POWERPOINT® LECTURE SLIDE PRESENTATIONby ZARA OAKES, MS, The University of Texas at Austin

Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings

HUMAN PHYSIOLOGYAN INTEGRATED APPROACH FOURTH EDITION

DEE UNGLAUB SILVERTHORN

UNIT 4UNIT 4

PART A

26 Reproduction and Development


Sex Determination

Dimorphism- physical differences in females and males other and reproductive organs. Physically distinct- breast, hips, muscle mass, areas

of body fat storage, etc.

Gonads produce gametes (eggs and sperm) Male gonads testes sperm

Female gonads ovaries eggs

Internal and external genitalia – glands and ducts that connect the gonads to the external genitalia

Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings Figure 26-1

Sex Determination

Chromosomes – a DNA segment that holds genes. Chromosomes come in pairs called homologous pairs Autosomes – code for

body characteristics but do not determine sex 22 pairs

Sex Chromosomes -X & Y men are XY

women are XX


Sex Determination

Inheritance of X and Y chromosomes

Each parent contributes ½ the genome to an offspring. During sex determineation; mothers always contribute the X chromosome. Father’s have a 50:50 chance of giving an X or Y

Each parent contributes ½ the genome to an offspring. During sex determineation; mothers always contribute the X chromosome. Father’s have a 50:50 chance of giving an X or Y


Sexual Differentiation

Bipotential tissues – undifferentiated tissues the can develop into male or female reproductive structures. SRY gene – sex-determining region of the Y chromosome that

will guides the development of male genitals.

Gonad - the reproductive organ that produces the gamete

Testis or ovary – primary reproductive organ, all other reproductive structures are accessory structures that make fertilization and pregnancy possible.

Wolffian duct- derived from the embryonic kidney, it develops into the vas deference once the testes release Anti-Mullerian hormone.

Mullerian duct - derived from the embryonic uterus, it develops into the fallopian tube while Wolfian duct disappear in the absence of testorone.


Development of Internal Organs

Figure 23-3a


Sexual Differentiation


Development of External Genitalia

Figure 26-3b


Gametogenesis Gamete production occurs in primary sex organs. Begins in

utero, stops during childhood, resumes in puberty and continues through adulthood. The process is timed differently in males & females

Meiosis- cell division occurring only in gametes that yields four haploid cells (different from mitosis) Primary gamete-produced at completion of Meiosis I. The

cell is genetically diverse, haploid (no chromosome pairs) and with sister chromatids (copies= 46 total)

Secondary gamete-produced at completion of Meiosis II. The cell is genetically diverse, haploid, and with no sister chromatids (23 total)

Haploid gamete- carries half the genome, matures into a viable cells that participates in fertilization


Mitosis yields two identical diploid cells. It’s happens in all body cells (somatic)

Meiosis yields four genetically diverse haploid cells. It only happens in sex cells (gametes)

Visual Summary

8.3

Mitosis Meiosis

Parentcell (2n)

Crossingover

2n

Daughtercells

2n

n n n

Parentcell (2n)

Chromosomeduplication

Chromosomeduplication Tetrad

n

Meiosis II

Daughter cells

Meiosis I

Comparing Mitosis and MeiosisComparing Mitosis and Meiosis


Gam

eto

gen

isis

in t

he

sem

inef

ero

us

tub

ule

s o

f th

e te

stes

. Ste

m c

ells

fir

st g

o

thro

ug

h m

ito

sis

& t

hen

mei

sosi

s

Gam

eto

gen

isis

in t

he

sem

inef

ero

us

tub

ule

s o

f th

e te

stes

. Ste

m c

ells

fir

st g

o

thro

ug

h m

ito

sis

& t

hen

mei

sosi

s


Spermatogenesis

Figure 26-5 (4 of 9)

Second meioticdivision

Secondary gamete divides. Rep

rod

uct

ive

adu

lt

FEMALE

MITOSIS

STAGE OF CELL DIVISION

Germ cell proliferation

46 chromosomesper cell (only two

shown here)

46(diploid)

MEIOSISDNA replicates but

no cell division occurs.

First meioticdivision

Primary gamete divides into two secondary gametes.

Em

bry

o

MALE

Sisterchromatids

Spermatogonia

Em

bry

oR

epro

du

ctiv

e ad

ult

Secondaryspermatocyte

Primaryspermatocyte

Spermatogonium

Sperm

One primary spermatocyteyields 4 sperm.

23 chromosomes(haploid)

2 sets of 46chromosomes

23 chromosomesduplicated

Spermatids

develop into

In males meiosis begins in adulthood after puberty, all cells generated by meiosis can develop into sperm.

In males meiosis begins in adulthood after puberty, all cells generated by meiosis can develop into sperm.


Maturation of Sperm


Spermatozoa Structure

Head Acrosome and nucleus

Midpiece Centrioles and

mitochondria

Tail (flagellum) Microtubules


Oogenesis

In f

emal

es s

tem

cel

ls g

o th

roug

h m

itosi

s an

d cr

eate

s al

l the

oo

cyte

s th

at c

ould

mat

ure

into

an

ovum

.

Mei

osis

beg

ins

befo

re b

irth,

is

arre

sted

,and

the

n re

sum

es a

fter

pu

bert

y bu

t is

not

com

plet

ed u

ntil

fert

iliza

tion

occu

rs.

In f

emal

es s

tem

cel

ls g

o th

roug

h m

itosi

s an

d cr

eate

s al

l the

oo

cyte

s th

at c

ould

mat

ure

into

an

ovum

.

Mei

osis

beg

ins

befo

re b

irth,

is

arre

sted

,and

the

n re

sum

es a

fter

pu

bert

y bu

t is

not

com

plet

ed u

ntil

fert

iliza

tion

occu

rs.


Gametogenesis & Fertilization

Figure 26-5 (9 of 9)

Second meioticdivision

Secondary gamete divides.

Disintegrates

Second polar body disintegrates.

Zygote

Rep

rod

uct

ive

adu

lt

(may notoccur)

Egg releasedfrom ovary at ovulation

One primary oocyteyields 1 egg.

FERTILIZATION

Unfertilized egg passesout of body.

FEMALE

MITOSIS

STAGE OF CELL DIVISION

Germ cell proliferation

46 chromosomesper cell (only two

shown here)

46(diploid)

Sisterchromatids

MEIOSISDNA replicates but

no cell division occurs.

First meioticdivision

Primary gamete divides into two secondary gametes.

Oögonium

Em

bry

o

Oögonia

Primaryoocyte

Secondaryoocyte(egg)

Firstpolarbody

MALE

Sisterchromatids

Spermatogonia

Em

bry

oR

epro

du

ctiv

e ad

ult

Secondaryspermatocyte

Primaryspermatocyte

Spermatogonium

Sperm

One primary spermatocyteyields 4 sperm.

23 chromosomes(haploid)

2 sets of 46chromosomes

23 chromosomesduplicated

Spermatids

develop into


Synthesis Pathways of Steroid Hormones

Steroid hormones contain cholesterol, are structurally similar and share production pathways with other steroid hormones

Ovary Progesterone Estrogen

Testis Testosterone


Regulation of Reproduction by Endocrine System

Both males and females produce the following, the primary target tissues are the gonads. The gonads produce androgens (predominate in males) and estrogens (predominate in females).

Hypothalamus: pulse generator of Gonadotropin releasing hormone (GnRH)

Anterior Pituitary Lutenizing hormone (LH)

Follicle stimulating hormone (FSH)

Inhibins and activins- influence the secretion of FSH


General PathwaysGeneral pattern of

hormonal control of reproduction

Long-loop: hormone production by gonads alters GnRH

FSH

LH

Short-loop: feedback from pituitary alters GnRH

Internal andenvironmental

stimuliCNS

Hypothalamus

Anteriorpituitary

Steroid andpeptide hormones

Gameteproduction

GnRHShort-loop negative feedback

Long-loop feedbackmay be negative

or positive

Stimulus

Integrating center

Efferent pathway

Effector

Tissue responseLH

Endocrinecells

FSH

Gonads(ovaries or testes)

KEYFem

ales only


Histology of the Testes

Seminiferous tubules contain Spermatogonia- goes through

various stages to become sperm (spermatogonia, spermatocyte, spermatids, & sperm)

Sertoli cells (sustentacular cells)- found between spermatogonia, form part of the blood-testes barrier produce inhibin & activin

Interstitial tissue (found outside of seminiferous tubules but within testicles) Leydig cells- produce testosterone,

active in fetus and after puberty


Regulation of Spermatogenesis

GnRH FSH Sertoli cells spermatocyte maturation

Inhibin feedback FSH,

testosterone

Short and long loops

LH

GnRHHypothalamus

Anteriorpituitary

Inhibin

Testes

FSH

Integrating center

Efferent pathway

Effector

Tissue response

Sertolicell

Cellproducts

Secondmessenger

Sertolicell

ABP TAndrogen-binding

protein (ABP)

Spermatogonium

Spermatocyte

KEY


Regulation of Spermatogenesis

GnRH LH Leydig cells testosterone sex characteristics

Inhibin feedback FSH,

testosterone

Short and long loops


Male Reproductive Structures Male reproductive structures are designed to create sperm, deliver it

internally, and provide it with chemicals to allow it to survive outside the body

Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings Figure 26-9b

Male Reproductive Structures

Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings Figure 26-8 (1 of 2)

Male Reproductive Structures Accessory glands: produce secretions that in addition to sperm, form semen.1. Seminal vesicles: secrete a fluid that contains fructose (sugar), nutrients, prostagladins to stimulate the urethra to contract, substances that suppress the immune system against sperm in females, enzymes the enhance sperm mobility, and enzymes that thicken the ejaculate. 2. Prostate gland: release a milky white fluid that enhances sperm mobility & thickens ejaculate. Susceptible to tumors & STDs.3. Bulbourethral glands: secrete a mucus for lubrication and neutralizes acid in urethra.

Accessory glands: produce secretions that in addition to sperm, form semen.1. Seminal vesicles: secrete a fluid that contains fructose (sugar), nutrients, prostagladins to stimulate the urethra to contract, substances that suppress the immune system against sperm in females, enzymes the enhance sperm mobility, and enzymes that thicken the ejaculate. 2. Prostate gland: release a milky white fluid that enhances sperm mobility & thickens ejaculate. Susceptible to tumors & STDs.3. Bulbourethral glands: secrete a mucus for lubrication and neutralizes acid in urethra.


Female Reproductive Structures

External genitalia Vulva

Labia Majora & Minora

Clitoris

Urethral & Vaginal opennings

Passageway Urethra

Vagina Hymen

Birth canal


Female Reproductive StructuresThe female reproductive system is designed for ova(egg) production, fertilization, fetal development, and fetal delivery. It involves a uterine and ovarian cycle


Female Reproductive Structures

These structures are supported by the broad ligament. The uterus is not the place of fertilization, thus changes to the lining of the uterus occur in preparation of implantation and then development of the fetus


Ovaries: Structures

Follicle: primordial, primary, secondary, matured (antrum), ruptured

Oocyte

Follicular cells

Thecal cells

Granulosa cells

Corpus luteum

Corups albicans


Phases of the Ovarian & Uterine Cycle Primary hormones

GnRH from the hypothalamus FSH and LH from the anterior pituitary Estrogen, progesterone, and inhibin from the ovary

Ovarian Cycle: Follicular phase: Follicle growth in ovary (egg matures) Ovulation: Ripened follicles and release of oocyte(s) Luteal phase: Ruptured follicle becomes corpus luteum in preparation

for pregnancy

Uterine Cycle: Menses: No pregnancy, Bleeding from uterus Proliferative phase: New layer of endometrium in preparation of

pregnancy Secretory phase: Conversion of endometrium to secretory structure


Hormonal Control of the Menstrual Cycle:Follicular Phase and Ovulation

LHFSH

GnRH

Androgens

Estrogens

Follicle

Granulosacells

Thecalcells

Corpus luteum

Progesterone

Ovum

LH

FSH

Follicle

Stimulus

Integrating center

Efferent pathway

Tissue response

Early to mid-follicular phase Late follicular phase and ovulation

EstrogenInhibin

Follicle

Granulosacells

Thecalcells

Inhibin

High estrogenoutput

Small amount ofprogesterone

Androgens

LHFSH

GnRH

KEY

Pituitary Hypothalamus

(a) (b)


The Menstrual Cycle: Ovarian & Uterine Cycle FSH stimulates follicular

development Maturation to secondary

and tertiary follicle

Granulosa cells produce estrogen

Positive feedback limits more follicles

Negative feedback decreases FSH and LH secretion

LH stimulates thecal cells to produce androgens

Follicular Phase

Phases of theUterine Cycle

Primaryfollicle Theca

Phases of theOvarian Cycle

Basal bodytemperature

(˚C)

Uterinecycle

Ovarianhormone

levels

Ovariancycle

Gonadotrophichormone

levels

MENSES

Estrogen

FSH

36.4

36.7

DAYS 28/0 7 14 21 28/0

ProgesteroneInhibin

LH


The Menstrual Cycle: Ovarian & Uterine Cycle High levels of estrogen

LH surge and FSH spike

Egg release

High levels of inhibin Inhibits production of

FSH

Decrease new follicle development

Low levels of progesterone Positive feedback

GnRH and LH

Follicular Phase Luteal Phase


Primaryfollicle Theca



(˚C)

Uterinecycle

Ovarianhormone

levels

Ovariancycle


levels

MENSES PROLIFERATIVEPHASE

InhibinEstrogen

Antrum

FSH

36.4

36.7

DAYS 28/0 7 14 21 28/0

Progesterone

LH


Hormonal Control of the Menstrual Cycle: Early to Mid-Luteal Phase

LHFSH

GnRH

Androgens

Estrogens

Follicle

Granulosacells

Thecalcells

Corpus luteum

Progesterone

Ovum

LH

FSH

Follicle

Stimulus

Integrating center

Efferent pathway

Tissue response

FSH LH

Corpus luteum(from ovulated

follicle)

EstrogenProgesteroneInhibin

GnRH

secretes

Early to mid-follicular phase Late follicular phase and ovulation Early to mid-luteal phase

EstrogenInhibin

Follicle

Granulosacells

Thecalcells

Inhibin

High estrogenoutput


Androgens

LHFSH

GnRH

KEY


(a) (b) (c)


The Menstrual Cycle: Ovarian & Uterine Cycle

Granulosa cells Form corpus luteum

Secretes progesterone

High levels of progesterone and estrogen maintain endometrium

Inhibin continues to limit new follicular development



Primaryfollicle Theca Ovulation

Corpusluteum

formation



(˚C)

Uterinecycle

Ovarianhormone

levels

Ovariancycle


levels


SECRETORY PHASE

InhibinEstrogen

Antrum

FSH

36.4

36.7

DAYS 28/0 7 14 21 28/0

LH

Progesterone


Hormonal Control of the Menstrual Cycle: Late Luteal Phase

LHFSH

GnRH

Androgens

Estrogens

Follicle

Granulosacells

Thecalcells

FSH LH

New folliclesbegin todevelop

Corpusluteum

dies

Tonic secretionresumes

Corpus luteum

Progesterone

Ovum

LH

FSH

Follicle

Estrogen andprogesterone

Stimulus

Integrating center

Efferent pathway

Tissue response

FSH LH

Corpus luteum(from ovulated

follicle)

EstrogenProgesteroneInhibin

GnRH GnRH

secretes

Early to mid-follicular phase Late follicular phase and ovulation Late luteal phaseEarly to mid-luteal phase

EstrogenInhibin

Follicle

Granulosacells

Thecalcells

Inhibin

High estrogenoutput


Androgens

LHFSH

GnRH

KEY


(a) (b) (d)(c)


The Menstrual Cycle: Ovarian & Uterine Cycle

Pregnancy Maintains high levels of

progesterone, estrogen, and inhibin

No pregnancy Decreased levels of

progesterone, estrogen, and inhibin

Menses

High levels of FSH and LH

New follicle development



Primaryfollicle Theca Ovulation

Corpusluteum

formation

Maturecorpusluteum



(˚C)

Uterinecycle

Ovarianhormone

levels

Ovariancycle


levels


SECRETORY PHASE

InhibinEstrogen

Antrum

FSH

36.4

36.7

DAYS 28/0 7 14 21 28/0

Corpusalbicans

LH

Progesterone


Procreation: Sexual Response

Phases of coitus (sexual intercourse or copulation) Excitement

Plateau

Orgasm

Resolution

Erection reflex CNS and spinal integration

Emission

Ejaculation

Erectile dysfunction (ED)


Erection and Ejaculation in Males

Figure 26-15 (5 of 7)

SensoryneuronMechanoreceptor

Erection

Penile arteriolesvasodilate.

Parasympatheticstimulated

Sympatheticinhibited

Tactilestimuli

Spinalcord

Stimulus

Receptor

Afferent pathway

Integrating center

Efferent pathway

Effector

Tissue response

KEY

Penis



Figure 26-15 (6 of 7)

Eroticstimuli

Higher braincenters

Ascending sensorypathway


Erection


Thoughtsof Sex!!



Tactilestimuli

Spinalcord

Stimulus

Receptor

Afferent pathway

Integrating center

Efferent pathway

Effector

Tissue response

KEY

Penis



Figure 26-15 (7 of 7)

Eroticstimuli

Higher braincenters

Descending autonomicpathways

Ascending sensorypathway


Erection


Thoughtsof Sex!!



Tactilestimuli

Spinalcord

Stimulus

Receptor

Afferent pathway

Integrating center

Efferent pathway

Effector

Tissue response

KEY

Penis


Pregnancy Prevention

Contraceptives Abstinence-also

prevents STDs Barriers-prevent

sperm from entering cervix

Surgical- prevent the entry of gametes

Pills- affect uterine lining and ovulation

http://portal.stii.dost.gov.ph/sntpost/frames/OcttoDec03/grapix/contraceptives.jpg

http://portal.stii.dost.gov.ph/sntpost/frames/OcttoDec03/grapix/contraceptives.jpg


Pregnancy Prevention


Fertilization

Sperm capacitation

Swimming and attractants

Egg contact

Penetration

Acrosomal reaction

Nuclear fusion

Cortical reaction

Zygote


Fertilization

Figure 26-16a


Fertilization When fertilization occurs the sperm does not enter the egg but the

fusion of the membranes causes the removal of receptors on the egg so no other sperm can fuse. Notice that meiosis II is only completed if the egg is fertilized

Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings Figure 26-18, steps 1–5

Zygote Development: Ovulation, Fertilization, and Implantation

Blastocyst

Inner cell

Days 5-9:Blastocyst implants.

Ovulation

Day 1:Fertilization

Days 2-4: Cell division takes place.

Days 4-5: Blastocyst reaches uterus.

Zygote Fallopiantube

Egg

UterusOvary

32 4

1 5


Embryonic Development


Further Embryonic Development

Chorion and amnion

Placenta Exchange site

Hormones

Human chorionic gonadotropin (hCG)

Human placental lactogen (hPL)

Estrogen and progesterone

Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings Figure 26-19a

The Placenta


Development of a Fetus






Regulators of Parturition

Labor onset

Stretch stimulus

Oxytocin

Prostaglandins

Positive feedback loop of parturition


Parturition: Birth Process Labor

Rhythmic

Uterine contractions

Cervical dilation

Delivery Baby

Placenta


Mammary Development

Modified sweat glands that are active in pregnant females to produce milk for the infant. These first appear as rudimentary structures in both men and women. When females reach puberty estrogen & progesterone cause the ducts grow but the glands do no fully develop. During pregnancy glandular alveoli form and produce milk shortly after childbirth.

Progesterone secreted in pregnancy actives secretion by the glands

High levels of prolactin after delivery stimulate the production of milk


Lactation: Milk Secretion

Prolactin-inhibiting hormone (PIH)

Prolactin

Milk production

Suckling

Inhibits PIH

Oxytocin

Let-down reflex


STD STATS Chlamydia- (bacteria) 3 million new cases per year- 75% have no symptoms. Painful

frequent urination, discharge, painful sex, sore throat, fever, nausea

Gonorrhea- (bacteria) 700,000 cases/year 50% have no symptoms or the same simptoms as Chlamydia

Herpes (virus) 1 million new cases/year, 45 million already have it. 1 in 4 pregnant women have herpes HSV-1 (oral sores) HSV-2 genital

HIV- 7,000 women give birth per year. 20% of infected babies develop AIDS and die by age 4

HPV- 75% of the reproductive population is infected ( 3 in 4 people)

Syphilis- 32,000 new cases/year. A pailess sore is followed by a rash, followed by rough “copper penny” spots on the palm and bottom of feet

Trichomoniasis- a bacteria that affects 5 million women/year. Foul smell, green discharge, itching,redness


http://picasaweb.google.com/mcmumbi/USMLEIIImages/photo#5089143973170425826http://picasaweb.google.com/mcmumbi/USMLEIIImages/photo#5089143973170425826

SyphillisSyphillis GonorrheaGonorrhea

Genital HerpesHealth.cdwriter.comGenital HerpesHealth.cdwriter.com

Trichomoniasiskiesbeter.nl

Trichomoniasiskiesbeter.nl


Chlamydia www.medinfo.ufl.edu

HPV –genital warts www.4healthyliving.org

HPV- abnormal cervix & penis

ispub.com

www2.hu-berlin.de

hopkinskimmelcancercenter.org

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