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