Chapter 5 Flashcards
1
Q
Development of the skeletal system is not ____ and reflects the influence of both _____ and _____ factors.
A
- static
- genetic
- external
2
Q
Embryonic skeleton =
A
cartilage model of bones
3
Q
Ossification centres:
A
sites gradually appear in the cartilage model where bone is deposited
4
Q
2 types of ossification centres:
A
- primary ossification centres
- secondary ossification centres
5
Q
Primary OC appear where?
A
mid portion of shaft of long bones
6
Q
Primary OC forms…
A
- from centre outward
- forms bone shafts
7
Q
Primary OC starts when?
A
at fetus age of 2 months
8
Q
In primary OC, bone cells are formed. What does this mean?
A
cartilage model bones of fetal skeleton begin ossifying
9
Q
Secondary OC is for ______ bone growth.
A
postnatal
10
Q
Secondary OC is aka…
A
epiphyseal plate
11
Q
Where are secondary OC located? What does this mean?
A
- areas near the end of long bones where new bone cells are formed and deposited
- bones grow in length
12
Q
Active secondary OC are indicated by what on a x ray?
A
- a line
- an area not opaque
13
Q
This line seen on a x ray is actually…
A
- layer of cartilage cells
- aka pressure epiphysis
14
Q
Epiphyseal plate has many _____ layers where cartilage cells ____, _____, _____, and _____ to leave new bone in place.
A
- cellular
- form
- grow
- align
- erode
15
Q
Bone is laid down at epiphyseal plates to…
A
increase the length of the bone
16
Q
Increasing length of bone depends on…
A
- adequate blood supply
- any injury that disturbs blood supply threatens the bone’s normal growth in length
17
Q
Unlike long bones, small round bones (ex. ones in _____ and _____) ossify from…
A
- wrist and ankle
- the centre outward
18
Q
When does growth at ossification centres cease?
A
at different times in different bones
19
Q
How does bone become fixed?
A
cartilage zone eventually disappears and the shaft (diaphysis) of the bone fuses with the epiphysis
20
Q
Almost all epiphyseal plates are closed by age ___.
A
18 or 19
21
Q
Since girls mature faster than boys, ossification centres appear…
A
at younger chronological ages in girls than in boys
22
Q
Since girls mature faster than boys, epiphyseal plates close…
A
at younger chronological ages in girls than in boys
23
Q
Children at the same chronological age could vary in skeletal age by ___ years or more.
A
3
24
Q
Appositional bone growth:
A
- Addition of new layers on previously formed layers so that a bone grows in girth
- Addition of new tissue layers under the periosteum (thick outer covering of the bone)
25
Traction epiphyses:
epiphyses at the sites where the muscles' tendons attach to bones
26
Osgood-Schlatter disease:
- Irritation of the traction epiphysis where patellar tendon attaches to the shin bone below the knee
- Refrain from vigorous activities
27
Overuse injuries to traction epiphyses during the growth period can...
threaten the pain-free movement at a joint later in life
28
Give an example of overuse injury to traction epiphyses.
- traction epiphysis near elbow
| - forcefully pronating forearm in throwing
29
Because linear growth of the body is almost completely the result of _____ growth, measures of height reflect...
- skeletal
| - increase of bone length
30
In youth, new bone is ____ _____ than older bone is ______ = _____.
- formed faster
- resorbed
- growth
31
In adulthood, bone formation begins to _____ and eventually cannot keep pace with ____ =
- slow
- resorption
- loss of bone tissue
32
Loss of bone tissue starts in mid ____ averaging about ___% bone mass/year.
- mid 20s
| - 1%
33
Children have _____ amounts of ______ and _____ components in their bone tissue.
- equal
- inorganic
- organic
34
Older adults have ___x more inorganic material = more _____ bones, subject to ______.
- 7x
- brittle
- microfracture
35
What 3 factors play a role in bone loss with aging?
- changes in certain hormone levels
- dietary deficiencies
- decreased exercise
36
Why do post menopausal women tend to have bone loss?
- decreased level of estrogen = loss of bone mass
- estrogen stimulates osteoblastic (bone-forming) activity
- estrogen lowers bone resorption
37
How do dietary deficiencies play a role in bone loss?
- prolonged deficiency of calcium in diet
- calcium lowers bone resorption
- shortage of vitamins and minerals
38
How does decreased exercise play a role in bone loss?
- Exercise has effect on maintenance of bone by increasing bone formation
- When someone engages in -PA, the mechanical forces applied to the bones help maintain bone thickness and density
- Significant increases in bone mass are even seen when older adults initiate exercise programs
39
Many older adults suffer from ______.
osteoporosis
40
Osteoporosis:
- major bone mineral disorder
- bone mineral density significantly below the average for young adults
- loss of bone strength
- bone becomes abnormally porous
41
What does it mean when bone becomes abnormally porous with osteoporosis?
enlargement of canals or formation of spaces in the bone
42
Osteoporosis increases risk of _______, especially at the _____.
- fractures
| - hip
43
Osteoporosis also adds difficulty to _____ _____.
fracture repair
44
Osteoporosis can lead to _______ of the ______ in the spine.
- microfractures
| - vertebrae
45
With osteoporosis, vertebrae may eventually ______, which means...
- collapse
- rib cage collapses forward
- lower edge resting on the pelvis
- posture becomes stooped
- standing height notably reduced
46
What is the key to reducing the effects of osteoporosis?
- early detection and treatment
| - increased awareness
47
Example of implementing strategies to minimize loss of bone tissue in adulthood:
women can maintain adequate calcium intake during adulthood so that they enter menopause with the highest bone mineral density possible
48
Muscular system changes over lifespan under the influence of _____ and _____ factors.
- genetic
| - extrinsic
49
Muscle fibres (cells) grow during prenatal life by what 2 ways?
- hyperplasia
| - hypertrophy
50
At birth, muscle mass accounts for ____ % of body weight.
23-25%
51
_____ continues for a short time after birth, but soon muscle growth occurs predominantly by _____.
- hyperplasia
| - hypertrophy
52
______ pattern of growth in weight reflects the growth of the muscle tissue.
sigmoid
53
Muscle cells grow in both _____ and _____.
- diameter
| - length
54
Amount of increase in muscle diameter is related to ...
the intensity of muscle activity during growth
55
Muscles must ______ ____ _______ as the skeleton grows.
increase in length
56
Lengthening of muscles is accomplished through:
- the addition of sacromeres (contractile units of muscle cells) at the muscle-tendon junction
- lengthening of sarcomeres
57
Sex differences in muscle mass during childhood:
- minimal
| - muscle mass constitutes a slightly greater proportion of body weight in boys
58
Sex differences in muscle mass during and after adolescence:
- muscle mass increases rapidly in boys up to about age 17
- girls add muscle mass only until age 13
- especially prominent in upper body musculature
59
Muscle mass ultimately accounts for ___% of men's body weight.
54%
60
Muscle mass ultimately accounts for ___% of women's body weight.
45%
61
Why are sex differences in muscle mass so dramatic in adolescence?
related to hormonal influences
62
Twitch:
Brief period of contraction of a muscle fibre (cell) followed by relaxation
63
2 main types of fibres in human muscles:
- slow twitch
| - fast twitch
64
Slow twitch:
- type I
- suited for endurance activities
- slower contraction-relaxation cycle
65
Fast twitch:
- types IIa, IIx, and IIb
| - suited to intense short duration activities
66
At birth, approximately ____% of muscle fibres have yet to differentiate into slow or fast twitch fibres.
15%
67
At birth, ____% of type II fibres cannot be clearly categorized.
15%
68
During the first postnatal year, the number of ______ fibres decreases.
undifferentiated
69
Heart = _____ tissue
muscle
70
The heart grows by _____ and _____.
- hyperplasia
| - hypertrophy
71
____ ventricle is larger than the _____ ventricle at birth.
- right
| - left
72
Left ventricle catches up after birth by...
growing more rapidly than the right
73
The heart generally follows the _____ pattern of whole-body growth.
sigmoid
74
One study found that left ventricular mass was _____ in overweight and obese children at ____ years.
- already greater
| - 2
75
Myth of early 20th century with regards to heart:
- Large blood vessels around the heart develop more slowly than the heart itself
- Implied that children who engaged in vigorous activity might be at risk
- Later shown that this myth was the result of a misinterpretation of measurements taken in the late 1800s
76
How does body comp begin changing in young adulthood?
proportion of lean body weight decreases, most often as a result of fat weight increasing
77
Only ___% of skeletal muscle mass is lost on average between the mid 20s and age 50.
10
78
How do changes in diet and PA affect shift in body composition?
- poor diet = increased fat weight
| - lack of PA = decreased muscle weight
79
After age ____, individuals begin to lose muscle mass at a greater rate.
50
80
On average, an additional ___% of muscle mass is lost by age 80.
30
81
At very old age, sedentary individuals with poor nutrition can lose as much as ___% of muscle mass they possessed in early adulthood.
50%
82
With old age, both ____ and ____ of muscle fibres appear to decrease.
- number
| - diameter (size)
83
Loss in numbers of muscle fibres is small before 50s (___%), and ____% after.
- 5%
| - 35%
84
Muscle fibres do not seem to decrease in size until the ____s..
70s
85
With old age, the heart's ability to .... declines.
adapt to an increased workload
86
The heart decreasing in adaptability as we get old may relate to:
- degeneration of the heart muscle
- Decrease in elasticity
- Changes in the fibres of the heart valves
- Major blood vessels lose elasticity
87
Most changes in the heart muscles of individuals are related to changes in ____ and resulting _____ rather than ...
- lifestyle
- pathology
- aging of the cardiac muscle fibres
88
____ and ____ mass are related to one another throughout the lifespan.
- bone
| - muscle
89
Use of the _____ stimulates the ____ to respond with increased ____ formation.
- muscle
- bone
- bone
90
Decline in bone and muscle mass is a ______ in the movement of older adults.
constraint
91
Any loss of muscle strength accompanying decreases in muscle mass with aging can lead to...
decrease in PA that is important to CV health
92
Adipose tissue plays a vital role in:
- energy storage
- insulation
- protection
93
Amount of adipose tissue ____ in early life.
increases
94
Adipose tissue first appears in the fetus at ____ months.
3.5
95
Adipose tissue increases rapidly during the last ___ prenatal months.
2
96
Adipose tissue accounts for only ___ kg of body weight at birth.
0.5
97
Rapid increase of fat in the firs ___ months after birth.
6
98
Highest peak weight velocity occurs in the ___ month.
first
99
Greater than average peak weight velocities =
increased risk of overweight and obesity
100
After 6 months, fat mass increases gradually until age ____ in both boys and girls.
8
101
____ tend to have slightly more fat mass at age 2.
Girls
102
In boys, what happens to adipose tissue throughout adolescence?
continues to increase gradually
103
In girls, what happens to adipose tissue throughout adolescence?
- experience a more dramatic increases
| - adult women have more fat weight than adult men
104
Fat weight during growth increases by both ____ and ____.
- hyperplasia
| - hypertrophy
105
After ___ years of age, it is more likely to maintain their relative fatness.
7-8 years
106
In childhood, ____ fat increases faster than _____ fat.
- internal (fat around the viscera)
| - subcutaneous fat (fat under the skin)
107
Subcutaneous fat decreases until age ____, then increases until age ____.
- 6-7
| - 12-13
108
Increase in subcutaneous fat ______ in girls, but boys typically _____ subcutaneous fat in midadolescence.
- continues
| - lose
109
Increases in fat cell number are significant because...
adipose cells persist once they are formed, even with malnutrition
110
2 periods are critical in the control of obesity:
- first 6 postnatal months
| - around puberty
111
Both sexes tend to gain _____ weight during the adult years. This reflects changes in _____ and ______ _____.
- nutrition
| - activity level
112
Total body weight begins to decline after age ____. This reflects _____ and ____ loss. _____ continues to increase.
- 50
- bone
- muscle
- body fat
113
How does body fat redistribute with aging?
- Subcutaneous fat on the limbs tends to decrease
| - Internal fat in the abdomen tends to increase
114
Abdominal obesity =
risk of CV disease
115
How is overweight and obesity a constraint to movement at any age?
- Movement is more effortful
- Joint movement can be restricted
- Social pressure related to body image and self-esteem can discourage participation in PA
116
2 control systems:
- nervous system
| - endocrine system
117
Hormones:
- Chemical substances secreted into body fluids by a gland
| - Have specific effects on the activities of target cells, tissues, or organs
118
Endocrine system’s regulation of growth is a complex and delicate interaction of ...
- hormones
- genes
- nutrients
- environmental factors
119
Why must hormone levels be delicately balanced?
Excess or deficiency of hormones may disturb the normal process of growth and development
120
4 hormones that we focus on:
- GH
- TH
- Gonadal hormones
- Insulin
121
All 4 hormones promote growth in the same way:
stimulate protein anabolism (constructive metabolism) resulting in the retention of substances needed to build tissues
122
GH influences growth during childhood and adolescence by...
stimulating protein anabolism so that new tissue can be built
123
GH is under control of ...
the CNS
124
GH is secreted by ....
anterior pituitary
125
GH is needed for _____ ____ after birth.
normal growth
126
Deficiency or absence of GH results in...
- growth abnormalities
| - in some cases the cessation of linear growth
127
TH secreted by...
thyroid gland
128
2 types of TH influence _____ ____ growth after birth. 3rd type plays a role in _____ growth.
- whole body
| - skeletal
129
_____ gland secretes ____ that regulates thyroid hormones.
- pituitary
| - TSH
130
TSH is increased by....
a releasing factor found in the brain's hypothalamus
131
Gonadal hormones affect ____ and ____ maturation, particularly during ______, by stimulating development of the ____ _____ ______ and ____ ____.
- growth
- sexual
- adolescence
- secondary sex characteristics
- sex organs
132
Androgens (specifically _____ and _____) hasten fusion of the _____ ____ _____ in the bones.
- testosterone
- androgens
- epiphyseal growth plates
133
Testosterone secreted by...
testes
134
Androgen secreted by...
cortex of adrenal glands
135
Testosterone and androgens promote _____ maturation (_____) at the expense of _____ growth. This explains why early maturers tend to be _____ in stature than late maturers.
- skeletal
- fusion
- linear
- shorter
136
Androgens play a role in the adolescent growth spurt of muscle mass by...
increasing nitrogen retention and protein synthesis
137
Why is muscle mass more pronounced in young men than young women (hormones)?
- men secrete both testosterone and adrenal androgens
| - women produce only the adrenal androgens
138
_____ and ____ ____ secrete estrogens.
- ovaries
| - adrenal cortex
139
Women have increased _____ secretion during adolescence, as with _____, it speeds ____ closure.
- estrogen
- androgens
- epiphyseal
140
Estrogen promotes ____ accumulation (primarily in ____ and _____).
- fat
- breasts
- hips
141
Insulin has a ____ role in growth.
indirect
142
Insulin is produced in _____.
pancreas
143
Insulin is vital to ______ metabolism, stimulating the transportation of ____ and _____ _____ through membranes.
- carbohydrate
- glucose
- amino acids
144
Presence of insulin is necessary for the full functioning of ____.
GH
145
Deficiency of insulin can ...
- decrease protein synthesis
| - detrimental at any time in life but especially at growth
146
One theory about cause of aging:
- Suggests that over time the nervous system, endocrine system, and immune system gradually fail to function
- Gradual failure can occur at different rates in the 3 systems
- Imbalances and reduced effectiveness within systems leave older individuals at increased risk of disease
147
____ function tends to decline with aging, making ____ disorders more prevalent among older adults. Long term increase in _____ hormone levels can be related to...
- thyroid
- thyroid
- thyroid
- congestive heart failure
148
Hypothyroidism is associated with ....
acceleration of aging systems
149
_____ hormone levels decrease with age, and _____ ______ therapy can counteract this.
- gonadal
| - hormone replacement theory
150
Hormone replacement theory:
- Ex. prescribing androgen supplements has been successful in countering muscle wasting and osteoporosis
- Need more info on the side effects
151
Incidence of ____ ____ diabetes increases markedly with age. Why?
- type 2
| - possible that older adults do not utilize insulin as effectively as younger adults to promote glycogen storage
152
Nervous system is the site of ____, _____ and _____.
- thinking
- analysis
- memory
153
Development of nervous system is important to...
- social
- cognitive
- motor development
154
Genes directs the development of the nervous system’s ...
structures and its main circuits
155
Extrinsic factors effect the development of the nervous system by...
fine tuning finer connections between nervous system cells
156
What 3 events occur prenatally in nervous system development?
- Formation of immature neurons
- Differentiation into general type
- Migration to a final position in the nervous system
157
Neurons:
cells of nervous system that receive and transmit information
158
By______, almost all the neurons that human brain will ever have are formed
third and fourth prenatal months
159
_____ receives impulses from other neurons.
dendrites
160
_____ transmits impulses to other neurons, glands, organs, or muscles.
axons
161
New neurons travel to a final destination during the ____ period. Some form the...
- prenatal
| - brainstem, cerebellum, cerebral cortex
162
Generally, neurons are in their final location by ...
the 6th prenatal month
163
Neurons _____, then grow an _____.
- specialize
| - axon
164
Synapse:
- Connection between 2 neurons
- Made by the release of chemicals called neurotransmitters from an axon
- These 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 impulse
165
Because of overproduction of neurons, ____ compete for the chemical trails. Some _____ and their ____ die off.
- axons
- axons
- neurons
166
Neurons fire _____ ____ that strengthen some of the connections between neurons. This is somewhat _____ prenatally and gets more organized as they grow and receive input from the ______.
- electrical impulses
- random
- environment
167
Describe how natural pruning occurs of both neurons and their branches and connections.
Weak or incorrect connections are sacrificed to make the neural network more efficient
168
What parts of nervous system development is susceptible to effects of environmental factors delivered via the fetal nourishment system?
- migration of neurons
| - branching of their processes
169
Faulty migration of neurons =
some disorders (epilepsy, autism, dyslexia)
170
Nicotine might affect...
- migration, branching, pruning of neurons
| - increased risk of mental retardation
171
Alcohol affects....
- improper neuron migration
| - babies with FAS known to exhibit lower IQ
172
At birth, the brain is about ___% of its adult weight.
25%
173
Brain growth increases rapidly after birth and reaches 80% of adult weight by age __. How does this happen?
- 4
| - Increase in the size of neurons, further branching to form synapses, increase in glia and myelin
174
Glia:
Cells of the nervous system that support and nourish the neurons
175
Myelin:
Insulating sheath around the axons
176
Rapid growth in early postnatal period continues to make neurological development...
very susceptible to extrinsic factors
177
Cerebral cortex:
Wrinkled surface of the brain containing millions of neurons and regulating many human functions and behaviours
178
____ is one of the most significant extrinsic factors influencing postnatal development of the nervous system. The brain restructures itself with _____.
learning
179
From early weeks of life and continuing over the lifespan, neural connections and pathways that are ______ are strengthened, those that are not used are _____.
- stimulated
| - weakened
180
_____ ____ and _____ brain structures are more advanced at birth than _____ brain structures.
- spinal cord
- lower
- higher
181
Lower brain centres involved in vital tasks:
- respiration
- food intake
- relatively mature
- mediate many reflexes and reactions
182
____ movement responses dominate fetus and newborn movements.
fetus
183
____ is involved in purposeful, goal-directed movement.
cortex
184
First clear evidence of successful intentional movement (reaching) occurs at ____ ____ months. Researchers assumed this signalled the first functioning of the ____.
- 4-5 postnatal months
| - cortex
185
Most recently used ____ scans and found activity in the ____ _____ at ___ age, increased activity at ____ , and adult levels at _____.
- PET
- frontal cortex
- 5 days
- 11 weeks
- 7-8 months
186
Development of myelin in the myelin contributes to....
speedy conduction nerve impulses
187
Myelin cells are made mostly out of ____.
fat
188
Myelin cells:
- Wrap around the outgoing neuron cell process (axon)
| - myelinated axons can fire nerve impulses at higher frequencies and speeds for longer periods than those not myelinated
189
Myelination:
The process whereby the axons of the neural cells are insulated when insulating myelin sheaths formed by Schwann (glial) cells wrap themselves around the axon
190
Spinal cord at birth:
- relatively small and short
- Central area contains tightly packed neuron cell bodies
- Roots lie just outside the cord, contain axons of the cord’s neurons and nerve cell bodies (sensory roots)
191
Marked increase in the myelination of the peripheral nerves occurs ____ weeks after birth
2-3
192
Nerve tracts = major _____ _____.
neurological pathways
193
2 major motor tracts:
- extrapyramidal
| - pyramidal
194
Extrapyramidal motor tract:
Involved in delivering the commands for both the random and postural movements made by the infant in the first days after birth
195
Pyramidal motor tract:
- Myelinates after birth
| - Functioning by 4-5 months and controls the muscles for finger movements
196
2 directions in the cord:
- cervical portion
| - lower portions
197
2 horns:
- motor (ventral) horns
| - sensory (dorsal) horns
198
Direction of myelination tends to be away from the ____ in the motor tracts.
brain
199
_____ pathways mature slightly faster than ____ pathways.
- sensory
| - motor
200
Neurogenesis:
division and propagation of neurons
201
Repercussions of age-related losses in the nervous system are wide spread:
- Can effect movements in recreational activities, ADL
| - Performance of cognitive tasks
202
Neural network model:
- Nervous system is seen as a neural network of links and nodes
- To respond to a stimulus, a signal begins at the input end of the individual’s nervous system and travels through the network to the output end
203
What happens to the neural network model with aging?
- Links break at random
- Signal must detour
- Increased response time
204
Broken links in the neural network model is the result of:
- Loss of neurons, dendrite, synapses
| - Decline in neurotransmitters
205
How does exercise help neural development?
- Reduced risk of stroke
- Increased branching of dendrites
- Maintenance of the neuron’s metabolism
- Maintains level of blood flow to brain
- Lessens loss of dendrites
- Stimulates neurogenesis
- Promotes new synaptic connections
- Improved cognitive function in older adulthood
