Physical and motor development of a child

1. Endocrine Glands

2. Introduction
• The endocrine system is the collection of glands that
produce hormones that regulate metabolism, growth and
development, tissue function, sexual function, reproduction,
sleep, and mood, among other things.
• Endocrine glands are glands of the endocrine system that
secrete their products, hormones, directly into the blood
rather than through a duct.

3. Hormones Function
• Reproduction and sexual differentiation
• Development and growth
• Maintenance of the internal environment
• Regulation of metabolism and nutrient
supply

8. Outline:
A. Endocrine system - body’s hormonal system
1. Endocrine gland-- secretes chemical hormones directly into blood stream
2. Pituitary gland
a. key endocrine gland located at base of brain
b. directly controlled by hypothalamus
c. “master” gland that triggers release of hormones from all other
glands and produces growth hormone
D. growth hormones-- directly regulate growth
3. Thyroid gland - growth and development
4. Testes - endocrine glands that produce testosterone and other androgens
a. testosterone-- specific male hormone important in adolescence
b. androgens-- general term for male hormones
5. Ovaries - estrogen and progesterone
a. estrogen-- key female hormone
i. keys female growth spurt
ii. responsible for development of adult sex organs
b. progesterone-- key female hormone
i. critical for menstrual cycle
ii. larger quantities in adolescence
6. Adrenal gland- contribute to maturation of bones and muscles
7. Endocrine glands continue function throughout life span

9. What do the endocrine glands secrete?
• Endocrine glands are glands of the endocrine system that secrete their
products, hormones, directly into the blood rather than through a duct. The
main endocrine glands include the pituitary gland, pancreas, ovaries, testes,
thyroid gland, and adrenal glands.
What do your glands do?
• Endocrine gland: a group of cells that makes hormones and sends
them into the blood to have effects on other cells. hormone a chemical
made in an endocrine gland in one part of the body. The hormone is
sent through the blood to another part of the body, where it helps other
cells do their job.

10. Physical and Motor
development
in
Endocrine Glands

11. The infant
A. Newborn capabilities
1. Reflexes - unlearned, involuntary response to stimuli
a. Survival reflexes—clear adaptive value
breathing, eye-blink
b. Primitive reflexes—unclear use
- Babinski reflex (toe fanning)
- typically disappear in early infancy
- useful for diagnosing neurological problems
2. Behavioral states - organized, individual patterns of daily activity
a. Sleep - wake cycle
- half of time in rapid eye movement (REM) sleep
- REM sleep may regulate levels of stimulation
b. states are highly individualized
c. sensing and learning
- infants can learn from experience
- capacity to move voluntarily limited

12. 3. Principles of growth
catch-up growth can occur following inadequate nutrition
b. cephalocaudal principle-- head to tail growth
c. proximodistal principle-- center outward to extremities
d. orthogenetic principle-- increasing differentiation

13. C. Physical behavior
1. Locomotors development
a. developmental norms - typical age of mastery
b. gross and fine motor skills
- gross - large muscle (kicking)
- fine - hand and feet (writing)
c. Crawling, walking, manipulating objects
d. global to differentiation to integration
e. crawling-- normally begins around 7 months
f. walking-- normally begins around 1 year
requires mature nervous system
requires muscle development
g. experience is critical (use of walkers may inhibit walking by restricting visual-
motor experience)

14. 2. Manipulating objects
a. innate grasping reflex weakens
b. pincer grasp-- thumb to forefinger develops
c. increased integration and differentiation
3. Emergence of motor skills
a. rhythmic stereotypes—repetitive movement common in early infancy
b. dynamic systems approach - use feedback to gain control of motor skills
c. walking is leaned not genetic with sensory feedback a key

15. The child
A. Steady growth
1. Steady but slower (ages 2 - puberty) 2-3 inches and 5-6 pounds per year
B. Physical behavior
1. Refinement of motor skills (initially awkward)
2. Improvements in eye/hand coordination often due to practice
3. Faster reaction times

16. The adolescent
A. Physical growth and sexual maturation
1. Adolescent growth spurt
2. Puberty - biological change resulting in sexual maturity and capacity to produce
children.
3. Growth spurt
a. female peak growth spurt around age 12
- females more fat in breast, hips
b. male peak growth spurt around age 13.4
- males more muscle mass
4. Sexual maturation
a. females-- menarche (first menstruation)
b. rate differs by ethnicity
c. males-- semenarche (initial ejaculation)
d. production of sperm typically comes after semenarche

17. 5. Variations in timing
a. genetic and hormonal influences
b. secular trend-- earlier maturation in industrial societies
i. better medical care and nutrition
c. anorexia nervosa-- eating disorder involving severe dieting
d. stress may delay sexual maturation
6. Psychological implications
a. concern with body image-- sex differences in concerns
i. boys more positive body images
b. both positive and negative reactions to sexual maturity
c. changes in relationships with parents

18. 7. Early versus late development
a. early maturation more advantageous for boys than for girls
i. early maturing boys more socially competent, self-assured
ii. early maturing girls less popular, in older peer group
b. late maturation more disadvantageous for boys than for girls
i. late maturing boys more anxious(balisa), less athletic
ii. late maturing girls more academic
c. impact of time of maturity fades with time
d. timing-of-puberty effect mediated by adolescent’s perceptions
B. Physical behavior
1. Strength and physical competence increases
2. Boys outperform girls-- biological and social factors
3. Gap between males and female physical skills narrowing

19. The adult
A. Physical appearance and structure
1. Most changes after 40
a. wrinkles, graying and thinning hair, changes in weight
b. osteoporosis-- disease resulting in loss of bone mass
i. female, small stature, smokers at risk
ii. calcium and exercise beneficial
c. ostheoarthritis-- aging of the joints due to use resulting
in pain and
restricted movement
B. Functioning and health
1. Large individual variation
2. Decrease in reserve capacity-- ability of organs to respond to
demand
3. Most adults can function successfully
C. Psychological implications
1. Stereotypes can lead to ageism-- prejudice against elderly
2. Reactions highly individual