Development and Aging Body Systems

Question 1

What are ten classic systems?

Answer 1

1) Integumentary system (Skin)
2) Musculoskeletal
3-6) Material exchange systems
-Respiratory
-Digestive
-Urinary
-Reproductive
7-10) Four systems that extend through the body
-Cardiovascular
-Nervous
-Endocrine
-Immune

Question 2

What are body constraints?

Answer 2

Body systems are influenced by extrinsic factors

A system that lags in development is the rate limiter

Question 3

What is ossification?

Answer 3

Ossification laying down of bone cells
Prenatal:in the middle portions of the long bone
Postnatal: at the end of the bone shaft
Adequate blood supply is necessary 
There is reduced ossification postnatal

Question 4

What occurs in postnatal growth of the skeletal system?

Answer 4

Length increases
-epiphyseal, growth, or pressure epiphyses
Diameter increases (oppositional)
Traction epiphyses: where muscles’ and tendons attach to bone
Girls ossify faster

Question 5

What happens during the cessation of bone growth?

Answer 5

Growth stops at different times for different bones
All typically close by age 18
Closure occurs at a younger age in girls

Question 6

What is the skeletal system like on adults?

Answer 6

Bones under go remodeling through life
Old bone is absorbed and new bone is formed
Bone growth slows, fails to keep up with absorption
Loss of bone mass (1%/yr)
More brittle
More inorganic material than organic
Osteoporosis

Question 7

What is the skeletal structure in adulthood?

Answer 7

Structure changes little unless one has osteoporosis

Rib cage osteoporosis = collapse of rib cage= stooped posture

Question 8

What is the muscular systems?

Answer 8

Prenatal growth involves hyperplasia and hypertrophy
Postnatal mainly hypertrophy
Follows sigmoid pattern
Minimal difference in childhood
Boys rapidly increase until 17
Girls add muscle until 13

Question 9

What is the differences in muscle fiber types?

Answer 9

Adults are composed of type I and type IIa and type IIx
At birth 15-20% of fibers are undifferentiated
By age 1 similar distribution in that of an adult
Proportions vary

Question 10

What happens to muscular system in adults?

Answer 10

Loss of muscle mass is minimal until age 50
By 80 30% less muscle mass
Loss occurs in number and size of the muscle fibers

Question 11

What is happens during growth of the cardiac muscles?

Answer 11

Prenatally: hyperplasia and hypertrophy
Postnatal: heart follows sigmoid pattern
Heart and blood vessel size is appropriate for body size in childhood and adolescence
In old ages heart loses elasticity

Question 12

What happens during adipose system growth?

Answer 12

Some fat is needed for energetic storage, insulation and protection
Fat increases rapidly until age 6 months and then gradually until 8 yrs.
Girls increase fat more dramatically than boys
Growth is both hyperplasia and hypertrophy

Question 13

What is fat distribution like?

Answer 13

Body fat distribution changes with growth
Children have more internal than subcutaneous
Subcutaneous increases from 6 until 12 in boys
Subcutaneous continues to increase in girls

Question 14

What is the increase like in the adipose system?

Answer 14

Cells increase by hyperplasia at
1) six months postnatal
2) Around puberty
Adipose cells persist one formed

Question 15

What is adipose tissue like in older adults?

Answer 15

Both men and women ten to gain fat in adult hood
Increases in trunk fat are notable, subcutaneous fat in limbs tends to decrease
Body weight may remain the same due to reduction in bone and muscle mass

Question 16

What is the endocrine system?

Answer 16

Regulated growth adn maturation through chemical substances (hormones)
Excess or deficiency can alter growth
Major hormones in growth
-Pituitary growth hormone
-thyroid hormone
-two gonadal hormones
Stimulate protein anabolism
Each one has a critical role in development

Question 17

What is growth hormone?

Answer 17

Secreted by the pituitary gland
Influences growth during childhood and adolescence
Deficiency can result in growth abnormalities or cessation of linear growth

Question 18

What are thyroid hormones?

Answer 18

TSH is released by anterior pituitary gland, which acts on thyroid to release thyroid hormones
Three are secreted
one influences whole body
two play roles in skeletal growth

Question 19

What are gonadal hormones?

Answer 19

Influence on growth, sexual maturation
Men and women have both in different proportions
Androgens
-Testes in boys, Adrenal gland in girls
-Hasten epiphyseal growth
-Promote growth of muscle mass

Estrogen

• Ovaries in girls, Adrenal cortex in boys
• Hastens epiphyseal growth
• Promotes fat accumulation

Question 20

What happens to the endocrine system during aging?

Answer 20

Theory: Gradual imbalance theory

• over time nervous, endocrine and immune systems fail to function
• imbalance and increased risk of disease

Question 21

What is the nervous system?

Answer 21

Genes direct it development

Extrinsic factors exert influence, especially in the formation of synaptic connections

Question 22

What happens during prenatal development of the nervous system?

Answer 22

Includes neural formation, differentiation into general types and migration
Once migrated, neurons develop axon to carry signals to neurons, glands, organs and muscles
Teratogens can interrupt branching

Question 23

What happens during early neural development?

Answer 23

Late in prenatal period, neurons start to fire impluses
-random
-then form circuits
Experience (stimulation) might play a role in synaptic prolifertation
Neural networks become more efficient with experience

Question 24

What happen during postnatal neurological growth?

Answer 24

Brain growth increases rapidly after birth
Growth involves these factors:
-Increase size of neurons
-Prolific branching to form synapses
-Increase in glial cells for support and nourishment
-Increase myelin to insulate
Stimulation of learning increases number of synaptic connections

Question 25

What is the brain structure?

Answer 25

Myelination of axons allow faster conduction of neural impulses

Question 26

What happens to the neural system in older adults?

Answer 26

Aging involves loss of neurons , dendrites, synapses, neurotransmitters, and myelin
One theory: breaks in neural network links cause detours and therefore slows
Exercise promotes improves cognitive function