This document discusses hereditary influences on human growth and development. It begins by explaining that hereditary material is contained within the 46 chromosomes present in a human zygote, which is formed when an ovum released by a woman's ovary is fertilized by a man's sperm. The zygote then begins replicating through mitosis, with each new cell containing the same 46 chromosomes and genetic material as the original cell. These cells differentiate and develop into the various muscles, bones, organs and other bodily structures. The document also discusses dominant and recessive traits, sources of congenital defects, several common sex chromosome abnormalities, and some major recessive hereditary diseases.

1. HUMAN GROWTH AND DEVELOPMENT
SSYM 1023

2. HEREDITERY
INFLUENCES ON
DEVELOPMENT

3. PRINCIPLES OF HEREDITERY
TRANSMISSION
We must start at conception to understand the
working of hereditery.
 Ovum released by a women’s ovary and on its way to
the uterus via the fallapion tube .
 Then fertilized by a man’s sperm.

4. THE GENETIC MATERIAL
• Sperm cell begins to disintegrate and
releasing genetic material.
• Ovum also release genetic material.
• New cells nucleus (zygote) forms which
contain hereditery
• Zygote is about 1/20th the size of the head
of pin.

5. What hereditery material is present in
human zygote?
• Hereditery information
provided by the father’s
sperm n the mother’s ovum.
• Contains 46 elongated
threadlike bodies
called chromosomes.

9. M
Genetic XY
Genetic XX

10. GROWTH OF THE ZYGOTE
AND PRODUCTION BODY
CELLS
Zygote moves through fallopian tube
Towards uterus
Begins to replicate itself through process of
mitosis

11. Zygote divides into two cells,
then become four, become
eight, become sixteen and so
on.
New cells with has identical 23
pairs of chromosomes(46 in all).
Same genetic material as the
original cell.
Makes up muscles, bones,
organs and other bodily
structures.

12. Male germ cells in
the testes produce
sperm.
Female germ cells in
the ovaries produce
ova.
Undergo meiosis process.
Crossing over takes
places

13. DOMINANT TRAITS
RECESSIVE TRAITS
Dark hair
Blown hair
Full head of hair
Pattern baldness
Curly hair
Straight hair
Facial dimples
No dimples
Normal vision
Color blindness
Normal blood clotting
Haemophilia
Normal blood cells
Sickle-cell anemia

14. EXAMPLE:

15. HEREDITERY UNIQUENES:
MULTIPLE BIRTH
• Two people share a genotype.
• A zygote split into separate but identical cells.
• Called as monozygotic ( or identical twins) because
developed from a single zygote and have identical genes.
• Occurs in 1 of of every
125 births.

16. SOURCES OF CONGENITAL DEFECTS
Congenital defects
Inherited defects
Chromosomal
abnormalities
Too many 0r too
few
chromosomes
Broken or
damaged or
chromosomes
Environmental defects
Genetic
abnormalities
Recessive
genes for a
disorder
Dominant
genes for a
disorder
Genetic
mutation
Prenatal exposures
to damaging effects
Complications of
the birth process

17. Four common sex chromosomes
abnormalities
Female
abnormalities
Male
abnormalities
TURNER’S SINDROME
KLINEFELTER’S SYNDROME
( XO)
( XXY, XXXY )
1 in 2500 births
1 in 750 births
POLY-X or
“SUPERFEMALE”
SYNDROME
SUPERMALE SYNDROME
( XXX, XXXX, XXXXX )
1 in 1000 births
1 in 1000 births
( XYY, XYYY, XYYYY )

18. Mentally retarded
Once in every 800
births
Slopping forehead,
protruding tongue,
Extra at 21st
chromosomes
-IQ average is 55
-normal children is 100
characteristics
short stubby
Slightly flattened nose, and
almond-shaped nose.
Congenital eye, ear and heart
defects

20. Diabetes
Cystis
fibrosis (CF)
hemophilia
MAJOR
RECESSIVE
HEREDITERY
DISEASES
Duchennetype
muscular
dystrophy
Phenylketonuria
( PKU )
Tay-Sachs
disease
Sickle-cell
anemia