Human Growth

Human Growth

& Development

List a developmental

milestone in human growth &

development

What is the relevance?

• Medical professionals need to understand stages of growth of development.Growth ~ refers to the measurable physical

changes that occur throughout a person’s life.Development ~ refers to the changes in

intellectual, mental emotional, social and functional skills that occur over time

What is the relevance?

• Different periods of life present unique challenges, changes, and problems.

• How one handles those challenges influences their health and the next stage in their lives.

Growth and Development

• Each phase of growth and development contains four major parameters– Physical development– Intellectual-cognitive development– Psycho-emotional development– Social development

Physical Development

• Bodily changes• Often times measurable–Height / weight–Muscle development–Changes in body organs

Intellectual-Cognitive Development

• Thinking skills– Learning how to solve problems– Make judgments– Deal with situations

Psycho-Emotional Development

• Changes in feelings– Love– Hate– Joy– Fear– Excitement

Social Development

• Interactions and relationships with other people– Family– Friends– Business associates

Growth and Development

Each of these parameters contain numerous developmental milestones.

Developmental Milestones ~ significant points in the growth process

Developmental Milestones

• Progress from the simple to the more complex– Person learns to sit, then crawl, then stand , then

walk, and then run– Children learn “gross” motor skills such as walking

first then learn “fine” motor skills such as using a crayon

Principles of Growth and Development

• Each stage establishes the foundation for the next stage.

• Stages proceed in an orderly pattern• ****However, the rate of progress varies

among individuals.*****• Health care providers must understand that

each life stage creates certain needs in individuals.

Principles of Growth & Development

- Development is influenced by genetics- Genes ~ units of hereditary material contained in

human cells- Each person’s set of genes is unique

- Environment also influences an individual- Do you believe we are more a product of our

environment, our heredity, or both? Why? - Discuss your stance with your neighbor

Miracle of life Part 1

At what point do you believe that a fertilized egg becomes a “person”?

Conception through Teenage Years• Pregnancy lasts 10 lunar months (40 weeks/ 9

calendar months/ 266-280 days)– Consists of 3 trimesters of 3 months each(1st, 2nd, 3rd)

(Below: Fetus at 16 weeks)

(Conception)

Growth and Development During Each Trimester

Trimester Length of Time Growth and Development

First Trimester Conception through third month

Development of major organ systems

Second Trimester Fourth through sixth month

Refinement of organ systems

Third Trimester Seventh through ninth month

Weight gain and maturation

First TrimesterThe First Trimester

Key Terms (First Trimester)

• Ovum ~ human egg of the female– About the size of a pencil dot on paper

• Sperm ~ male reproductive cell – Too small to see with the human eye

• Conception = Fertilization– Union of the nuclei of the egg and the sperm

• Fallopian tube ~ tube that extends from the uterus to the ovary

Ovary, Fallopian Tube, Uterus

What Happens the First Trimester?

• Conception occurs when one sperm, traveling with millions of other sperm, penetrates the ovum.

• Conception occurs in the first third of the fallopian tube

Timing is Everything

• In the female ovulation occurs at midcycle , around day 14.

• The egg lives for about 24 hours after ovulation.

• Sperm usually live between 12 and 48 hours.– (some survive up to 72 hours)– Female sperm live longer*

Timing is Everything

• For fertilization to occur, sexual intercourse must take place around the time of ovulation, generally no earlier than 72 hours before ovulation and no later than 24 hours after ovulation.

• Reflex ovulators ~ women who ovulate in response to having intercourse– Rabbits are reflex ovulators

How Fertilization Occurs

• During intercourse, about 200-600 million sperm are released.

• Only about 100,000 survive the acidic environment of the vagina.

• Sperm swim through the uterus and into the fallopian tube towards the egg.

• Within 1-2 hours they are gathered around the egg.

How Fertilization Occurs

• One (and only one) sperm penetrates the egg and unites with the nuclei of the egg.

• Zygote ~ fertilized egg*

How Fertilization Occurs• The single-cell zygote has 46 chromosomes,

23 from the egg and 23 from the sperm.• The zygote begins to divide, forming

clusters of cells that slowly makes its way through the fallopian tube toward the uterus. (3-5 days)

• The cells (morula) look like a cluster of grapes with a root like structure on the back which will become the placenta.

How Fertilization Occurs

• When this cluster of cells reaches the uterus, it implants itself into the plush lining, where it grows and develops into a human being with billions of cells.

• Implantation ~ embryo adheres to uterus lining.• Implantation occurs when the cluster attaches

itself into the upper rear wall of the uterus

How Fertilization OccursAmniotic sac develops over this group of cells– A membrane that surrounds the fetus– The outer group of cells starts to develop into a

shape that is the head and a tail• Embryo ~ human being growing in the uterus

from the time of conception to about the eighth week.

How Fertilization Occurs

http://www.webmd.com/baby/slideshow-conception

• the great sperm race

Pro life or Pro Choice? Why???

****JUST AS YOU HAVE YOUR OWN OPINION, SO DO OTHERS!

RESPECT THEIRS AS WELL!!****

The First Trimester• 21-25 days, a heart begins to beat

and nervous system starts to develop!

• 4 weeks: embryo is ¼“ long– Arm buds bulge– Consists of head, body, and tail– Eyes and ears can be detected

• 5 weeks: a nose is visible• 6 weeks: almost ½”, floating in

amniotic sac– Leg buds appear

• 7 weeks: ¾” and can move hands– Fingers are defined, organs are visible,

skull bones are growing.

Embryo at 3 wks

Embryo at 7 wks

The End of the 1st Trimester• 8 weeks: almost 1”, liver is

large, bones are forming, testes and ovaries are distinguishable– At 8 weeks, developing

infant is called a fetus• 10 weeks: 1 ½”– 2”,

kidneys produce urine, lower trunk muscles develop– About to end the 1st

trimester– baby peeing in womb

Fetus at 10 weeks

The 2nd Trimester• 12 weeks: begins the 2nd

trimester; head is 1/3 of the entire length, ribs can be seen, hair begins to grow

• 16 weeks: 4 ½” long, weighs 3-4 oz; human looking face, testicles of males position for descent. (can tell sex of fetus)– Mother feels fetal movements,

known as “quickening”– Fetus blinks and begins sucking– Heartbeat can be heard with

fetal instruments (fetal doppler)– Hearing fetus heartbeat

Fetus at 14 weeks

Fetal doppler

2nd Trimester (cont.)

• 20-24 weeks: 12” long, major systems continue to develop, bones continue to form. – Fetus may suck its

thumb– Eyes remain sealed

closed– Survival at this point

of pregnancy is unlikely

• Fetus ~ end of 8th week till birth

3rd Trimester• 28 Weeks: 14” and 2.5 lbs– Viable with an

increased threat from infection & immaturity

• Major developments in 3rd tri: weight gain, growth in length, & maturation of organs

• Although viable, best place for growth & development is the uterus!

• 38-40 weeks = FULL TERM• Fetal influences: whatever the

mother consumes (alcohol, drugs, and tobacco can harm infant even in small amounts)

• fetus growth

The Placenta• Disc shaped structure about 7” in diameter

and 1” thick.• Highly vascular• Site where nutrients and waste are exchanged

between mother and baby.• Oxygen, food and other nutrients diffuse from

the mother’s blood to the embryo’s• Carbon dioxide and other waste diffuse from

the embryo’s blood into the mother’s blood to be excreted.

• placenta images