Development and Aging Body Systems Flashcards
What are ten classic systems?
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
What are body constraints?
Body systems are influenced by extrinsic factors
A system that lags in development is the rate limiter
What is ossification?
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
What occurs in postnatal growth of the skeletal system?
Length increases
-epiphyseal, growth, or pressure epiphyses
Diameter increases (oppositional)
Traction epiphyses: where muscles’ and tendons attach to bone
Girls ossify faster
What happens during the cessation of bone growth?
Growth stops at different times for different bones
All typically close by age 18
Closure occurs at a younger age in girls
What is the skeletal system like on adults?
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
What is the skeletal structure in adulthood?
Structure changes little unless one has osteoporosis
Rib cage osteoporosis = collapse of rib cage= stooped posture
What is the muscular systems?
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
What is the differences in muscle fiber types?
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
What happens to muscular system in adults?
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
What is happens during growth of the cardiac muscles?
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
What happens during adipose system growth?
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
What is fat distribution like?
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
What is the increase like in the adipose system?
Cells increase by hyperplasia at
1) six months postnatal
2) Around puberty
Adipose cells persist one formed
What is adipose tissue like in older adults?
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
What is the endocrine system?
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
What is growth hormone?
Secreted by the pituitary gland
Influences growth during childhood and adolescence
Deficiency can result in growth abnormalities or cessation of linear growth
What are thyroid hormones?
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
What are gonadal hormones?
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
What happens to the endocrine system during aging?
Theory: Gradual imbalance theory
- over time nervous, endocrine and immune systems fail to function
- imbalance and increased risk of disease
What is the nervous system?
Genes direct it development
Extrinsic factors exert influence, especially in the formation of synaptic connections
What happens during prenatal development of the nervous system?
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
What happens during early neural development?
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
What happen during postnatal neurological growth?
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
What is the brain structure?
Myelination of axons allow faster conduction of neural impulses
What happens to the neural system in older adults?
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
