This document presents an overview of human embryology and fetal development from conception to birth in 3-sentence stages. It describes the key events from fertilization through cell division and implantation in the first few weeks. The major organ systems then develop throughout the subsequent weeks, with the fetus growing in length and weight. By week 35, the fetus is near its birth length and continues gaining fat in preparation for birth from week 36 to 40, when the fully developed fetus is ready to be delivered.

1. EMBROLOGY
AND DEVELOPMENT STAGES
PPT PRESENTATION BY 1st YR BPT
STUDENT
UZMA TAMBE
SHUBHAM MISHRA

2. DEFINITION OF EMBRYOLOGY
• EMBRYOLOGY IS THE STUDY OF
DEVELOPMENT EVENTS THAT OCCUR DURING
PRENATAL STAGE.

3. DEVELOPMENT STAGES OF FETUS
• 1ST ocuur the maturation where ogenesis and
spermatogenesis occur
• Fertilization occurs where the sperm enters
the ovum, means the fusion of sperm cell with
oocyte and form zygote

5. 1st week
• Zygote undergoes mitotic cellular replication
as CLEAVAGE.
• Cleavage is the formation of smaller cell called
BLASTOMERES

6. • FORMATION OF MORULA
• Zygote undergoes into cell
division.
• 4 cells- at 2days
• 8 cells - at 2.5 days
• 16 cells - at 3 days

7. 2nd week and 3rd week
• No development occurs since fertilization
hasn’t actually occurred
• At 3rd week – embryo will implant to the wall
of uterus . Fertilized egg ( zygote ) begins to
develop into a hollow ball of cells blastocyte.

8. 4TH WEEK AND 5TH WEEK
• FROM PLACENTA AND EMBRYONIC SAC MEMBRANE .
• FORMATION OF YOLK SAC.
• PRIMITIVE STREAK
• DEVELOPS.
• PRIMARY STEM VILLI APPEARS.
• DEVELOPMENT OF BRAIN,
SPINAL CORD,VERTEBRA,
HEART, GASTROINTESTINAL TRACT.

9. WEEK 6TH TO 7TH
• EMBRYO GROWS 4mm TO 9mm IN LENGTH
• BEGINS TO CURVE INTO C- SHAPE
• THE FETAL HEART BULGES , DEVELOPES
FURTHER AND BEGINS TO BEAT IN A REGULAR
RHYTHM.

10. 8TH TO 9TH WEEK
• THE EMBRYO MEASURES ABOUT 13mm TO 18mm
• DURING 8TH WEEK LUNGS BEGINS TO FORM AND ALSO LYMPHATIC
SYSTEM.
• DEVELOPMENT OF EXTERNAL GENITALIA BEGINS AND UPPER AND LOWER
LIMBS CAN BE CLEARLY DISTINGUISH.
• 9TH WEEK ELBOW AND TOES ARE VISIBLE, HAIR FOLLICLES BEGINS TO
FORM.
AFTER 10TH WEEK OF DEVELOPMENT , THE ORGANISM IS CALLED FETUS.
MAJOR STRUCTURE WILL CONTINUE TO GROW.

11. WEEK 10TH TO 12TH
• EMBRYO MEASURES 30-80MM
• Baby's nose, mouth, and eyes starts taking shape. Tooth buds and caps are
becoming recognizable.
• Baby's fingers will soon begin to open and close, his toes will curl, his eye
muscles will clench, and his mouth will make sucking movements.
Your baby has ten fingers and ten toes (no more webbing), and peach-fuzz
hair begins to grow on tender skin.

12. 13TH TO 16TH WEEK
• The baby's fingers and toes have now separated, nails begin to form and
some hair may even be growing. The baby's head can now move and facial
features continue to develop. At this stage, the baby weighs around 25
grams. The mother's uterus is expanding and changing position to be
above the pelvis.

14. 17TH TO 21 WEEK
• Seventeen weeks into your pregnancy, or 15 weeks after conception,
toenails begin developing. Your baby is becoming more active in the
amniotic sac, rolling and flipping. His or her heart is pumping about 100
pints of blood each day.
• FETUS lengths ABOUT 20cm.
• MOTHER CAN FEEL THE FETUS MOVING.

16. WEEK 23
• FETUS IS ABOUT 28cm
• 23 weeks after conception, your baby might be able to
respond to familiar sounds, such as your voice, with
movement.
• Your baby is spending most of his or her sleep time in rapid
eye movement (REM), when the eyes move rapidly even
though the eyelids are closed.

17. WEEK 27
• THE baby weighs almost 2 lbs – about as much
as a head of cauliflower – and is around
15inches long. At this stage, babies sleep and
wake at regular intervals, opening and closing
their eyes and maybe even sucking their
fingers. With more brain tissue developing,
THE baby's brain is very active now.

19. WEEK 31
• THE FETUS IS ABOUT 38-43 CM AND WEIGHS ABOUT 1.5KG.
• BREATHING OCCURS , BONES ARE FULLY DEVELOPED .
• THE AMOUNT OF BODY FATS INCREASE MEANS THE PREGNANT LADY WILL
GAIN WEIGHT.

20. WEEK 35
• During the 35th week of pregnancy, she already might be close to her
birth length, near 18 inches from head to toe, and she continues to build
up necessary fat, especially in her shoulders. Within your now-crowded
uterus, your baby might shift her movements from kicks and punches to
more rolls and wiggles.

21. WEEK 36- 40
• THE FETUS IS FULLY DEVELOPED AND IS ABOUT 48 TO 53CM
• FINGERNAILS EXTEND BEYOND FINGERTIPS
• SMALL BREAST BUD ARE PRESENT ON BOTH SEXES.
• HEAD HAIR IS NOW COARSE AND THICKEST.
• In the last weeks of pregnancy
the rapidly growing fetus turns
head- down:a baby ready to be born.

23. Thank you
• From Uzma & Shubham