EMBRYOLOGY

KID VIDEO

SEXUAL REPRODUCTION

•FERTILIZATION- FUSION OF GAMETES TO FORM A ZYGOTE (FERTILIZED EGG)•** GAMETES FORMED DURING MEIOSIS

•GAMETES: SPERM & EGG

A. SPERM- MALE GAMETE•HIGHLY MOBILE

•FRAGILE; PRODUCE MILLIONS PER DAY

•PRODUCED IN TESTES FROM PUBERTY TO DEATH

OVA (EGG) – FEMALE GAMETE

LARGE, STRONG CELL BORN WITH A FINITE NUMBER OF IMMATURE EGGS – EVENTUALLY RUN OUT (MENOPAUSE)

RELEASED DURING OVULATION – 1 PER MONTH

PRODUCED IN OVARIES

SPERM STRUCTURE

SPERM STRUCTURE

MALES - SPERMATOGENESIS

DIFFERENTIATION- WHEN (STEM) CELLS BECOME SPECIALIZED (STRUCTURE & FUNCTION)

EX: SPERM CELLS, LIVER CELLS, BRAIN CELLS ETC.

Note- Differentiate into sperm cells

FEMALES - OOGENESIS• PRODUCES 1 MATURE EGG & 3 POLAR BODIES (ALLOW HAPLOID CELL)

FEMALE REPRODUCTIVE SYSTEMOVARIES (1 INCH)

WHERE OVA ARE PRODUCED

FALLOPIAN TUBES (OVIDUCTS)PASSAGEWAY FOR THE EGGWHERE FERTILIZATION TAKES PLACE

UTERUS (3 INCHES)ORGAN WHERE BABY GROWS AND DEVELOPSINNER LAYER = ENDOMETRIUM BLOOD

VESSELS

CERVIX LOWER PORTION OF THE UTERUS; ABOUT 1 INCH LONG

VAGINASTRONG MUSCULAR CHAMBER; SERVES AS A BIRTH CANAL

FEMALE REPRODUCTIVE ORGANS

FUN FACT •FEMALES BORN WITH 400,000 IMMATURE EGGS BUT ONLY SEVERAL HUNDRED WILL BE RELEASED DURING THE REPRODUCTIVE YEARS BEFORE SHE REACHES MENOPAUSE

MENSTRUAL CYCLEControlled by hormones

Ovulation releasing of the egg from the ovary

Menstruation- shedding lining of uterus

MenopauseHonors Ovulation

MALE REPRODUCTIVE SYSTEM

TESTES WHERE SPERM ARE PRODUCED

SURROUNDED BY SCROTUM, WHICH KEEPS TESTIS COOL ENOUGH FOR SPERM TO FORM

EPIDIDYMIS SPERM FULLY MATURE AND ARE STORED

Vas deferens

Passageway for sperm

GlandsAdd secretionsProstate gland – thin fluid for nourishment

Seminal vesicle – (thick fluid contains fructose) - nutrients

Bulburethral gland – basic fluid to balance acid of urine in urethra and acidity of vagina

UrethraExit for semen and urine

H

GlandsAdd secretionsProstate gland Seminal vesicle - provides fluid nourishment for sperm)Bulburethral gland

UrethraExit for semen and urine

A

WHITE BOARD CHECK!READY?

#1. WHERE IN THE FEMALE REPRODUCTIVE SYSTEM DOES THE BABY GROW?

UTERUS

#2. WHAT IS THE TERM FOR THE RELEASE OF EGGS?

OVULATION

#3. NAME FOR MALE GAMETE & WHERE ITS PRODUCED IN MALE SYSTEM

SPERM, TESTES

#4. NAME FOR FEMALE GAMETE & WHERE ITS PRODUCED IN FEMALE SYSTEM

OVA (EGG), OVARY

#5. WHERE DO SPERM FULLY MATURE?

EPIDIDYMIS

#6. FERTILIZATION IS THE FUSION OF ________ TO FORM A _________ WHICH TAKES PLACE IN THE _________ TUBES.

GAMETESZYGOTE

FALLOPIAN

WHICH ONE IS THE HUMAN

EMBRYO?

1

2

FERTILIZATION

FERTILIZATION - OCCURS IN

FALLOPIAN TUBE 1. Sperm approaches egg2. Acrosome releases enzymes to digest

jelly layer3. Proteins on sperm head bind receptor

proteins on egg (prevents other species’ sperm)

4. Cell membranes of egg & sperm fuseNucleus Video (5min)

5. SPERM NUCLEUS ENTERS EGG

6. FERTILIZATION ENVELOPE FORMS•1 SECOND LATER, EGG IMPENETRABLE•VITTELINE LAYER (ZONA PELLUCIDA) OUTER LAYER HARDENS

7. EGG AND SPERM NUCLEUS FUSE TO CREATE A DIPLOID NUCLEUS

LABEL AND COLOR IN THE MALE AND FEMALE REPRODUCTIVE SYSTEMS IN YOUR GUIDE.* COLORED PENCILS ARE UP FRONT

CLEAVAGE/CELL DIVISION

CLEAVAGE – SERIES OF CELL DIVISIONS DNA REPLICATION, MITOSIS, & FINALLY CYTOKINESIS OCCUR RAPIDLY

NUTRIENTS IN EGG NOURISHMORULA – SOLID BALL OF CELLS

RESULTS FROM ~3 DAYS OF CLEAVAGEBLASTULA (BLASTOCYST = HUMAN) – HOLLOW BALL OF CELLS AFTER ~6-7 DAYS OF DIVISION

HOW MANY CHROMOSOMES DOES EACH HUMAN CELL HAVE AT EACH LEVEL OF EMBRYONIC DEVELOPMENT?

IMPLANTATION•DEFINITION: BLASTULA BURIES INTO THE LINING OF THE UTERUS

• 6-12 DAYS AFTER FERTILIZATION

• BLASTOCYST RELEASES ENZYMES THAT SOFTEN THE TISSUE OF THE ENDOMETRIUM

•ONCE THIS OCCURS, HORMONE HCG RELEASED PREGNANCY TESTS MEASURE THIS

GASTRULATION•PHASE DURING EARLY DEVELOPMENT – AFTER BLASTULA

•FORMS THE “GASTRULA”

•CELLS MIGRATE AND BECOME DIFFERENTIATED

•EVENTUALLY ORGANS FORM FROM THESE 3 LAYERS

•GASTRULATION PURPOSE: CREATE THE 3 PRIMARY GERM LAYERS•ENDODERM (INNER LAYER) – LININGS OF DIGESTIVE

•MESODERM (MIDDLE LAYER)–SKELETON, MUSCLES

•ECTODERM (OUTER LAYER)– SKIN

http://upload.wikimedia.org/wikipedia/commons/d/d4/Cell_differentiation.gif

PLACENTA – FORMS BETWEEN 9-12 WEEKS

Connects the mother and fetusProvides oxygen and nutrientsRemoves CO2 and wasteProvides protective antibodies

Blood of mother and baby NEVER mix – (blood barrier)

OTHER THINGS CAN STILL CROSS:- VIRUSES (HIV AND OTHERS)- MOST DRUGS (PRESCRIPTION AND NON-PRESCRIPTION)- ALCOHOL AND CHEMICALS IN CIGARETTES CROSS- FETAL ALCOHOL SYNDROME – CAN CAUSE MENTAL RETARDATION

PLACENTA

TERM FOR THE SERIES OF CELL DIVISIONS THAT OCCUR DURING DEVELOPMENT

CLEAVAGE

TERM FOR THE HOLLOW BALL OF CELLS

BLASTULA

TERM FOR THE SOLID BALL OF CELLS

MORULA

WHAT HORMONE IS RELEASED DUE TO IMPLANTATION INTO THE UTERINE WALL? HCG

TERM FOR FORMING THE PRIMARY GERM LAYERS

GASTRULATION

LIST THE 3 GERM LAYERS AND THEIR POSITION IN THE GASTRULA

ENDO – INNER

MESO – MIDDLE

ECTO- OUTER

WHAT IS/ARE THE FUNCTION(S) OF THE PLACENTA?

PROVIDE NUTRIENTS & O2/ REMOVE CO2 AND WASTE

WHAT IS THIS?

GASTRULA

WHAT IS THIS?

BLASTULA

WHAT IS THIS?ASSUME IT’S SOLID

MORULA

GESTATION•PERIOD OF TIME IT TAKES FOR GROWTH AND DEVELOPMENT

•40 WEEKS OR 9 MONTHS

•3 TRIMESTERS

•Fertilization•Cleavage•Implantation•Development •Growth•Parturition

- Length of gestation varies depending on organism

Humans 266 days

Rodents 21 days

Dogs and cats 60 days

Cows 270 days

Giraffes 420 days

Elephants 600 days

FIRST TRIMESTER

Month 1Fertilization, Cleavage, implantation

HCG (hormone) is produced signaling pregnancy

Embryo until 8 weeks

FIRST TRIMESTERMonth 2 – ¼ inch to 1 inch (bean)

Nervous system is first organ system to form

Heart develops and is the first organ to begin working

Called a FETUS at 8 weeks Legs and arms start to form Eyes and ears become visible Placenta begins to form Umbilical cord connects mother and embryo Every essential organ has begun to form Bones begin to form, muscles can contract

FIRST TRIMESTERMonth 3 – 1 ½ to 3 inches

Baby is 1.5 inches long Organ systems continue to develop.

Genitalia clearly form (not always visible in ultrasound)

Eyelids close (won’t open until week 28)

Teeth buds form

SECOND TRIMESTER (4-6 MONTH)

• MONTH 4: 6 INCHES • SKIN IS TRANSPARENT, THIN

LAYER OF HAIR FORMS ON THE HEAD

• BABY CAN SUCK ITS THUMB, KICK AND PUNCH (MORE MOVEMENT)

• DOCTORS CAN TELL IF IT IS MALE OR FEMALE ON ULTRASOUND

• BABY DRINKS AMNIOTIC FLUID

• FINGERPRINTS FORM

Month 5: 8 inchesMother can feel baby movingNails, eyelashes and eyebrows formSkin is covered by soft hairHeartbeat of baby can be heard by doctor

SECOND TRIMESTER (CONT’D)

•MONTH 6 – 10-14 INCHES• AIR SACS OF LUNGS BEGIN TO DEVELOP

• LANUGO (THIN HAIR) COVERS THE WHOLE BODY

• LAYER OF FAT DEVELOPS

• EYES COMPLETELY DEVELOP

• LIVER AND PANCREAS WORK HARD TO DEVELOP

• WEEK 24-26 IF THE BABY WERE BORN IT COULD SURVIVE WITH THE HELP OF MEDICAL TECHNOLOGY

SECOND TRIMESTER

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THIRD TRIMESTER (7-9 MONTH)

•MONTH 7 (15-17 INCHES)

• STORES FAT

• LUNGS NOT FULLY DEVELOPED, BUT RHYTHMIC BREATHING BEGINS TO OCCUR

• BONES FULLY DEVELOPED (SOFT)

• EYELIDS OPEN

•MONTH 8• FETUS DESCENDS INTO THE HEAD DOWN POSITION

• LANUGO HAIR DISAPPEARS, SKIN LIGHTENS FROM RED COLOR

• PERIOD OF RAPID GROWTH

THIRD TRIMESTER•MONTH 9: 19-21 INCHES

•WEEK 38 – CONSIDERED “FULL TERM” AND IS READY TO LIVE OUTSIDE THE MOTHER’S BODY

•MOTHER PROVIDES BABY WITH ANTIBODIES FOR PROTECTION

• ALL ORGANS ARE DEVELOPED

Embryo Pictures

STEPS OF PARTURITION (DELIVERY)1.DILATIONOXYTOCIN IS RELEASED CAUSING:CONTRACTIONS TO BEGINCERVIX TO DILATE

BABY’S HEAD PUSHED DOWN

AMNIOTIC SAC BURSTSH

2. EXPULSIONCERVIX IS FULLY DILATED (10 CM)CONTRACTIONS OCCUR EVERY 1-2 MINSTHE CHILD IS DELIVERED

3.AFTERBIRTHTHE PLACENTA (AFTERBIRTH) IS DELIVERED

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TWINS1. FRATERNAL TWINS

• RESULT FROM TWO EGGS AND TWO SPERM

2. IDENTICAL TWINS• RESULT FROM ONE EGG AND ONE

SPERM

• DURING CLEAVAGE THE ZYGOTE SEPARATES INTO 2 CLUSTERS

3. CONJOINED TWINS• RESULT FROM ONE EGG AND ONE

SPERM

• DURING CLEAVAGE THE ZYGOTE

ALMOST SEPARATES