Ch 5

What else does bone porosity affect? • because cortical bone is stiffer than trabecular bone, it can withstand greater ______ but less ______. • because trabecular bone is spongier than cortical bone, it can undergo more ______ before fracturing

stress, strain; strain

Cerebral Subcortex includes:

- Cerebellum - Medulla Oblongata - Pons - Diencephalon • Thalamus • Hypothalamus

Nervous System: • ______ direct its development. • _______ exert influence, especially in the formation of synaptic connections

- Genes - extrinsic factors

Brain Structures: • _________________ centers are more advanced at birth than higher brain structures • ___________ gradually becomes more functional after birth (specialization of areas of this continue well into adulthood) • _______ of axons allows faster conduction of neural impulses • Direction of myelination tends to follow direction of conduction.

- Spinal cord and lower brain - cerebral cortex - myelination (improves speed and frequency of firing)

Nervous System in Older Adults: • ______ involves loss of neurons, dendrites, synapses, neurotransmitters, and myelin. - Neurogenesis: • One theory of aging suggests that breaks in neural network links cause detours and therefore slowing. • ______ promotes improved cognitive function.

- aging - division and propagation of neurons - exercise (minimizes loss of neurons and synapses with aging)

Growth Hormone (GH)" • Growth hormone is secreted by _________. • It is necessary for _____ growth. • _______ can result in growth abnormality.

- anterior pituitary gland - normal - deficiency

Adipose System- Early Development: • Some ___ is needed !! - Fat plays vital role in: • Fat increases rapidly until age ______; then gradually until age _____. • In adolescence, _____ increase fat more dramatically than _____ do. • Growth is by _______ & _______(the latter more dramatic in adolescence). • Individual variability is great

- fat - energy storage, insulation, and protection - 6 months, 8 years - girls, boys - hyperplasia and hypertrophy

Prenatal Neural Development: • Process generally includes neuron: (Neurons proliferate __________/min) - During the __________ prenatal months, almost all the neurons in the human brain are formed - neurons contain a cell body, 100,00 dendrites which receive impulses from other neurons • Once in place, neurons develop _____ to carry signals to neurons, glands, organs, muscles. - neurons are in final location by the ____ prenatal month - neurons specialize • ______ might disturb normal migration and branching.

- formation, differentiation into a general type, and migration(migration process is vital to normal brain development) - 250,000 - third and fourth - axons - 6th - teratogens

Adipose Tissue in Older Adults: • Both men and women tend to ____ fat during adulthood, but this is not inevitable - Avg american woman gains 11.8 kg (26lbs) and men gain 8.2 kg 18 lbs) • Increases in ______ are notable, but ______ fat on ______ tends to decrease. * total body weight declines after age 50 but it reflects loss of bone and muscle, as body fat continues to increase

- gain - trunk fat, subcutaneous, limbs

Endocrine System in Older Adults: • Imbalances may develop among the nervous, endocrine, and immune systems (may occur at different rates in the 3 systems)- called: • ________ are more prevalent. • Decreasing _______ levels are associated with loss of bone and muscle tissue. - older adults maintain secretion levels of _____ comparable with those of younger adults

- gradual imbalance theories - thyroid disorders (thyroid function declines with aging) - gonadal hormone - insulin (type 2 diabestes increases a lot with age tho)

Fat Distribution: • Body fat distribution changes with ______. • Children have more ________ than subcutaneous fat. • Subcutaneous fat increases from age ___ or ___ years until age __ or __ in boys and girls. • Subcutaneous fat then continues to increase in _____

- growth - internal - 6 or 7; 12 or 13 - girls

Endocrine System: • Plays role in regulating growth and maturation through chemical substances called ________. • Excess or deficiency can alter _______. • Major hormones involved in growth: • These hormones stimulate __________ (tissue building) • _________ feedback loops regulate hormone levels. • Each hormone may have a critical role in development at specific phases in life span. • ______ plays indirect role (decrease protein synthesis), and is vital for ________ metabolism; also necessary for full functioning GH

- hormones - growth • Growth hormone • Thyroid hormones • Two gonadal hormones - protein anabolism - Endocrine-neurological - insulin, CHO

Cardiac Muscle: • Prenatally, the heart grows by ______ & _____ • Postnatally, heart follows _______ pattern. • _______ & ______ size is appropriate for body size in childhood and adolescence. • In old age, heart can lose ______ and valves can become more ______ (depending partly on lifestyle).

- hyperplasia and hypertrophy - sigmoid growth -heart and blood vessel - elasticity, fibriotic

Early Neural Development: • Late in prenatal period, neurons start to fire electrical impulses (first at ______, then forming ______) • Experience might play a role in _____________ (strengthening some connections, weakening others). • Neural network becomes more efficient with experience.

- random, circuits - synaptic proliferation

*Diencephalon (hypothalamus and and thalamus):

- regulate emotion

Muscular System in Adults: • Loss of muscle mass (__________) is minimal until age ______ (loss 1% of bone mass/yr: starting as early as the mid 20s) • By ____, average ___% of muscle mass is lost • Loss occurs in number of muscle fibers after ____ and fiber size (the latter usually after age ____). • Whether type II fibers undergo greater loss is unclear

- sarcopenia, 50 - 80, 30% - 50, 70

Postnatal Neurological Growth: • Brain growth increases rapidly after birth. • Rapid growth involves these factors: 1) Increases in ________. 2) Prolific branching to form ________. 3) Increases in ______ for support and nourishment of neurons 4) Increases in _______ to insulate axons • _____% of its adult weight at birth / _____% at 4 • Stimulation of learning increases number of synaptic connections.

- size of neurons - synapses - cells (glia) - myelin - 25%; 80%

Gonadal Hormones: • Androgens: * Secreted by ______ (boys) and ______ (boys, girls). * Hasten _______ closure. * Promote growth of _______ (↑nitrogen retention and protein synthesis). • Estrogen: * Secreted by ______ (girls) and ______ (girls, boys). * Hastens _________ closure. • Promotes accumulation of _____.

- testes; adrenal gland - epiphyseal growth plate - muscle mass - ovaries, adrenal gland - epiphyseal growth plate - fat

Thyroid Hormones: • These are secreted by the _______. • Two influence _______ growth. • One plays a role in ______ growth.

- thyroid gland - whole body - skeletal

Muscle Fiber Type: • Adult muscle is composed of ___________________ fibers • At birth, ________% of fibers are undifferentiated and ______% of type 11 fibers cannot be clearly categorized • By age ____, distribution of muscle fiber type is similar to adult distributions • Exact proportions vary among individuals

- type I (slow‐twitch; endurance activities) and type IIa, IIx, and IIb (fast‐twitch; intense short duration activities) - 15-20%; 15% - age one

Cessation of Bone Growth: • Growth at the epiphyseal plates stops at different times for different bones • All typically close by age _______. • Closure occurs at a younger age in girls: * Humerus: _______.

18 or 19; 15.5 years for girls and 18.1 for boys

At birth, muscle accounts for ___ to ___% of body weight

23-25

Appositional bone growth:

addition of new layers on previously formed layers so that a bone grows in girth

Two major functional components of the brain:

cerebral cortex and cerebral subfortex

Osteoporosis:

characterized by bone mineral density significantly below the average for young adults and by a loss of bone strength; increases risk of fractures

Synapses:

connection between two neurons; made by the release of neurotransmitters from the axon. the neurotransmitters cross a small gap between neurons, then permeate the cell wall at the dendrite, or cell body, of a receiving neuron to trigger an electrical pulse

Cerebellum:

coordinating body movement (posture, balance, coordination)

A system that lags in development can be a:

developmental rate limiter. • Give an example of a system (skeletal, muscle, adipose, neurological, endocrine) acting as a developmental rate limiter.

The ______ has many cellular layers where cartilage cells form, grow, align, and finally erode to leave new bone in place

epiphyseal plate

Traction Epiphyses:

epiphyses at the sites where muscles tendons attach to bone

Early development: Growth centers where new bone cells are produced until the _______ during late adolescence or early adulthood

epiphysis closes

Cerebral Cortex includes:

frontal lobe, occipital lobe, parietal lobe, and temporal lobe

Ossification centers:

gradually appear in the cartilage model where bone is deposited

Prenatal growth involves ____________ & __________

hyperplasia(increase in number of muscle cells) and hypertrophy(increase in muscle cell size)

Postal growth mainly involves __________ which is predominately how muscle growth occurs

hypertrophy

Muscle cells grow(increase) in diameter and length: - The amount of increase in muscle fiber diameter is related to ______________ during growth - Muscles must also increase in length as skeleton grows, and this increase is accomplished through the addition of _____________.

intensity of muscle activity; sarcomere

Skeletal Structure in Adulthood: • Structure itself changes ______ unless one has osteoporosis • __________ leads to rib cage collapse, stooped posture, and reduced height • Extent of bone loss is influenced by:

little; osteoporosis; hormone levels, diet, and exercise (exercise increases bone formation and calcium and estrogen supplementation lower bone resorption; women can maintain adequate calcium intake during adulthood so they enter menopause with highest bone mineral density as possible)

Sex differences in muscle mass are _______ during childhood: • Differences between the sexes become marked in adolescence (especially in upper body musculature)

minimal ( muscle mass increases rapidly in boys until about age 17 and accounts for 54% of body weight and girls add muscle until age 13 and makes up 45% body weight)

Temporal lobe:

primary auditory cortex (perception, memory, speech)

early development: Ossification begins at ___________ in the midportions of long bones (humerus &femur) and begin to form bone cells starting at fetal age of _____.

primary centers; 2 months

Frontal lobe:

reasoning, planning, movement, emotion, motor skills, higher level cognition

medulla oblongata:

regulates breathing, heart rate and physiological process

*Pons:

regulates sleep

Skeletal System in Adults: • Bone undergoes ________ throughout the life span • Old bone is absorbed __________; new bone is formed _________ (old bone is replaced by new bone) • In adulthood, bone growth slows, fails to keep pace with reabsorption. • Bone composition also changes over life span; Bone becomes more brittle (older adults have 7 times more inorganic material, making bone more brittle and subject to microfracture) - The result is loss of _________, starting early as the mid 20s and averaging about ___% of bone mass per year

remodeling; osteoclasts, osteoblasts; bone tissue

early development: Postnatal bone growth occurs at _________ at the ends of bones

secondary centers (also called epiphyseal plates/pressure epiphyses)

Parietal Lobe:

sensory information (pressure, touch, pain); movement orientation

The ____________ pattern of growth in weight reflects the growth of muscle tissue:

sigmoid

Bone is thus laid down at the epiphyseal plates to increase _________.

the length of the bone

Bone is thus laid down at the epiphyseal plates to increase _________.

the length of the bone; - process of laying down new bone depends on blood supply. an injury that disturbs this blood supply threatens the bones normal growth in length

Occipital lobe:

visual stimuli and info

Body Systems (Individual Structural Constraints):

• Body systems are influenced by both genetic and extrinsic factors. • It is important to know -the average pattern of change within each system -the range of individual variations for a system

Skeletal System- early development:

• Prenatally, the embryo has a cartilage model of the skeleton