Test Two Flashcards
what is a motor unit
neuron and all the muscle fibers it innervates
what are afferent neurons
enter spinal cord
carry info from PNS to CNS
treatment for PD
replenish dopamine
levodopa
maybe brain surgery if drug therapy does not work
what is concentric
shortening
muscle force greater than external load, against gravity
example of static/isometric muscular contractions
wall sits, planks
what muscle is under voluntary control
skeletal
in the middle stages, more plaques and tangles form and
memory becomes impaired
also form in area of speech and proprioception
most people diagnosed during this stage
what is a cross bridge
when actin and myosin come together to create a power stroke
what age do the number of muscle fibers begin to decrease
after mid 20’s
what are some mild symptoms of AD
confusion and memory loss
disorientation; getting lost in familiar settings
problems with routine tasks
changes in personality and judgement
what is the sympathetic nervous system
supply the heart, smooth muscle, sweat glands
fight or flight
accelerates breathing and heart rate; pupils dilate
AD is named after
alois alzheimer
autopsy on women, dramatic shrinkage of cerebral cortex and fatty deposits in small blood vessels, dead and dying neurons, and fatty deposits in and around neurons
what is the basic unit of the nervous system
a neuron
what is body composition
how much muscle mass in the body
what are some factors in sarcopenia
decreased levels of sex hormones decreased levels of anabolic hormones (insulin, growth hormone) increased cytokine production physical inactivity malnutrition smoking
what determines muscle action
origin and action
alpha two neuron characteristics
small, they dont require a lot of force
when using slow controlled velocities under MVC uses what fiber
both one and two
what is sarcopenic-obese
fat gain
how does motor unit remodeling occur
slower, less force production, less efficient, less precise control of movements
what are antagonist muscles
muscle groups that are opposite of each other
why would fast twitch be recruited last
low intensity exercise predominantly uses slow twitch but when there is an inccrease in intensity forces then fast twitch is needed
what is MVC
maximum voluntary contraction
how to diagnose PD
hard to do bc similar to other diseases
25% misdiagnosed
no adequate blood or lab test
in advanced stage of AD what is mostly damaged
cortex
what is a synapse
contact points between neurons (gap between)
what are some severe symptoms of AD
loss of speech
loss of appetite; weight loss
loss of bladder and bowel control
total dependence on caregiver
what acts against myelin attack causing demyelination
T cells
the interior of the muscle is divided into bundles of muscle fibers called
fascicles
is it possible for older people to build muscle
yes, but it is not as fast as younger adults with resistance training
increase activities of daily living
what accounts for the shape of the muscle
different arrangements of fascicles within a muscle
what are the types of muscular contractions
static/isometric
dynamic
isokinetic
what parts of the brain are affected by AD
cortex, hippocampus (help form memories)
where would you find cardiac muscle
in the heart
what are the most common symptoms of MS
numbness/tingling vision disturbances fatigue muscle weakness difficulty moving balance and coordination problems chronic pain cognitive function bladder and bowel dysfunction dizziness and vertigo depression abnormal temp regulations and sweating responses
can you grow more muscle fibers
no you are just born with it
what are thick filaments
myosin
a “nerve” refers to
a bundle of neurons
a group of many axons of neurons that travel in the same location
what do myofibrils contain
smaller myofilaments
can one neuron innervate both type one and two fibers
no its one or the other
what causes PD
unknown
chemicals or free radicals
toxins
genetic factors
what do myofilaments contain that help with contraction
thick and thin filaments
what is the force and endurance of long and parallel muscles
not a lot of force but a lot of endurance
when is juvenile onset of PD
occur before age 20
what are the two types of muscle fibers
slow twitch (type 1) fast twitch (type 2)
what is an axon
carries impulses away from the cell body and to muscle fibers it innervates
is muscle mass linked with mortality
yes
looks of type 1 fiber types
red, oxidated, small, produce less force
what are the primary symptoms of PD
TRAP tremor rigidity akinesia postural changes
diagnosing MS
difficult to diagnose in early stages
need evidence of two distinct exacerbations separated by 30 days (RRMS) or
slow progression of signs and symptoms over 6 months (PPMS)
how do neurons communicate
the axon of one neuron will communicate with the dendrite of an adjacent one
what is sarcopenia
intrinsic age related process
decrease in strength with age because of reduced-fat free mass
loss of function
decline in quantity and quality of muscle
what is the greek origin of sarcopenia
poverty of flesh
inactivity-induced loss of muscle mass predominantly affects the…
lower body and is most rapid in the initial days/weeks of inactivity
can an axon of neuron communicate with other parts of a neuron
yes
what system signals the muscle fiber to begin cross bridge cycling
nervous system
what is the all or none law for motor units
a motor unit is either activated completely or not at all
action potential must be large enough
all muscle fibers in unit must contract
treatments for MS
focus on speeding recovery from attacks, slowing progression of disease, and managing symptoms drug therapy exercise no cure meditation, diet, accupuncture
are males or females more likely to get parkinsons
males, but coffee helps decrease likelihood in men
what is the pathophysiology of ALS
motor neurons degenerate and die
cease communication with skeletal muscle, atrophy of skeletal muscle or voluntary muscle
what are the three types of muscles in humans
skeletal, cardiac, smooth
each fiber is innervated by how many neurons
1
what happens when muscles age
loss in fiber size and fiber number
more pronounced type 2 fiber atrophy
loss of motor units
collectively leads to a loss of strength and power
what is PPMS
primary progressive MS
slow but nearly continuous worsening of their disease from onset, with no remission
variations in rates of progression over time, occasional plateaus and temp minor improvements
how much of muscle mass is appendicular (arms and legs)
75%
what is eccentric
lengthening
muscle force less than external load, with gravity
do the myosin and actin attach if the muscle is over stretched and has little overlap
no
how does sarcopenia occur
in absence of disease
accelerated by inactivity and poor nutrition
why use CT or MRI to diagnose PD
rule out other disorders with similar symptoms
the generation of tension that happens in a muscle is due to
to binding of myosin to actin
what is familial ALS
occurs more than once in family, genetic dominant inheritance
faulty genes
50% chance offspring gets it
what is muscle atrophy
the wasting away or loss of muscle
wha fiber is used for anaerobic activities
type two
when is MS usually diagnosed
between ages of 15 to 59
what is the quickest way to lose muscle
bed rest
and poor nutritional habits as well
what happens if we lose ~ 40% of lean body mass?
death, including organs in lean body mass
what is flexion
bending movement that results in a decrease in the angle of a joint
as PD develops neurons…
degenerate and can no longer produce adequate amounts of dopamine which cant move from cortex to spinal cord
what is SPMS
secondary progressive MS
start out with RRMS followed by steadily worsening disease course with or without occasional flare ups, minor remissions, or plateaus
most people with RRMS develop this form 10 year after initial diagnosis
what are some risk factors to PD
advancing age sex family history declining estrogen levels agricultural work low levels of folate in diet head trauma
what does ALS stand for
amyotrophic lateral sclerosis
lou gehrigs disease
what fiber is the first to be recruited for any activity
type one
what parts of the brain are minimally affected by AD
medulla, pons, midbrain, and thalamus
function of pennate muscles
less ability to shorten but more sarcomeres
look like feathers and attach to multiple spots on the bone
where are skeletal muscles connected to
bone
when do you see tremors in PD
seen at rest
in 75% of patients
begins on one side of body
general function of nervous system
control of internal and external environments
body’s master control and communication
somatic and autonomic systems
what is parkinsons disease (PD)
a motor system disorder resulting from the loss of neurons which produce the neurotransmitter dopamine
what creates the striated appearance in muscle
myofilaments run in repeating patterns along the length of the myofibril
when does EARLY onset of dementia/ AD occur
before age 65
very rare
what is guamanian ALS
ALS in guam and trust territories
ingestion of particular plant that has neurotoxin
what do sarcomeres mean
force
when does the onset of AD occur
later stages of life
what do the neurons do that innervate skeletal muscle fibers
signal them to contract
atrophy
decrease in size
the loss of neurons is thought to be caused by what in AD
plaques and tangles
pennation results in a loss of force within each fiber because
decrease of fiber length
diagnosis of AD
medical history (family)
physical exam
neurological exam (reflexes, speech, coordination)
brain imaging
what separates adjacent sarcomeres
Z disc (line)
list the cross bridge cycle in order
cross bridge formation
power stroke
release
return to “loaded” position
is there a cure for AD
no
what else does DEXA show
bone density
what fibers make up all skeletal muscles
both type one and two
what surrounds the muscle fascicles
perimysium
what is the inflammatory cascade in MS
inflammation
demyelination
axonal loss
what are the two major components of the nervous system
central and peripheral nervous system
looks of type 2 fibers
white, anaerobic
is sarcopenia a slow or fast process
fast during a catabolic crisis
what fiber is slow to fatigue
type one
what is efferent
motor neuron, delivers impulse from CNS to effector
what is dementia
general term for memory loss and mental deterioration serious enough to interfere with daily life
what are neurotransmitters
chemical messengers released at terminal end of nerve to pass signal on to another cell
diffuse across synapse
what are thin filaments
actin
muscle cells are also known as
muscle fibers
what are some showings of akinesia in PD
small handwriting
reduced arm swing when walking
absence of facial expressions
what does amyotrophic mean
wasting of muscle
what is progressive relapsing MS
steadily worsening disease from the onset but also have a clear acute relapse with or without remission
continuous disease progression
circumduction
movement of limb in a circular motion
what are the contractile structure of the cells
myofibrils
what fiber is used first during MVC
type one then type two
alpha one neurons innervate what type of fiber
2
what fiber generates force quickly
type two
what is multiple sclerosis
an INFLAMMATORY, demyelinating disorder of CNS causing plaques in white matter of CNS
chronic auto immune inflammatory disorder
what are some consequences of sarcopenia
lower metabolism= fat gain increase risk for disability loss of balance increased risk of falls increased mortality
anabolic resistance is also known as
blunted muscle protein synthesis
is progression slow or fast in MS
slow, over 10 to 25 years
which fiber type is recruited first
slow twitch then fast
who has a lot of type 1 muscle fibers
endurance athletes due to aerobic activity
can you grow new muscle fibers
no you are born with a certain number
the degree of pennation directly affects what
the number of sarcomeres per cross sectional muscle area
repeating myofilaments are called
sarcomere
muscle loss during bed rest appears to be driven by
a reduction in muscle protein synthesis
what is the structure of muscle fibers
long cylinder shaped cells
the ratio of muscle fibers to motor neurons affects what
the precision of movement
what causes loss of strength
selective atrophy in type 2 fibers
motor units are recruited based on…
order of fiber type
what are dendrites
receive and conduct impulses toward the cell body
what happens when myostatin is reduced or absent
skeletal muscle hypertrophies
what is average age people are diagnosed with PD
60 but increased risk with advancing age
what does the peripheral nervous system contain
cranial and spinal nerves
how are muscle fibers oriented
along the longitudinal axis of the muscle
symptoms of MS are
unpredictable and vary from person to person
depends on where lesions occur on myelin sheath
what is alzheimers diease (AD)
is a progressive and fatal brain disease which destroys brain cells (neurons)
shrinkage of brain
what is bradykinesia
slowness of movement
what neuron makes up the motor division
efferent
do most people with MS have the relapsing form of the disease or not
most do
so PD affects what
motor output which is movements and coordination
when does early onset of PD occur
between ages of 21 and 40
risk fact for familial ALS
inherited genetic defect SOD-1 gene
what is a motor unit
the neuron and all the muscle fibers it innervates
which fiber contains more mitochondria and is used in everyday activities
type one
what is a power stroke
shortening occurs as the myosin heads snap back pulling on the actin filaments
rotation
movement around a central axis
how do you assess sarcopenia
dual energy X-Ray absorptiometry (DEXA) assessment to determine appendicular lean mass
what are some risk factors for AD
age
family history
certain rare genes almost guarantee AD
younger onsent AD is inherited
who is affected by MS
Caucasians of northern European descent
mostly women
function of long and parallel muscle fibers
“longitudinal muscles” greater ability to shorten but less sarcomeres
what sheath of connective tissue binds the MUSCLE together
epimysium
PD symptoms progress…
slowly
rate depends on person
doctors believe what is required to diagnose someone with PD
tremor
where would you find the smooth muscle
surrounds various organs and tubes
blood vessels, bronchial tubes, uterus
AD accounts for how many cases in dementia
50 to 80%
what are the three types of ALS
sporadic
familial
guamanian
what is wasting
unintentional loss of weight including both fat and fat free mass
when age are people diagnosed with ALS
40 to 70
how much body weight does skeletal muscles make up
around 45%
MVC at fast velocities uses what fibers
only type one
what is sporadic ALS
most common
no exact known cause
what is ALS
rapidly progressive neurological degenerative disease that attacks the nerve cells responsible for controlling voluntary muscles
loss of ability to initiate and control muscle movement
leads to paralysis and then death
what is dynamic muscular contraction
muscle contraction that produces movement of the skeleton
what are efferent neurons
conduct impulses away from brain or spinal cord (CNS) to glands and muscles (PNS)
what are the two subdivisions of the autonomic nervous system
sympathetic and parasympathetic nervous system
what are the types of MS
relapsing- remitting MS secondary progressive MS primary-progressive MS progressive-relapsing MS can either be mild, moderate or severe
when you get older what else decreases in number that helps control skeletal muscle
motorneurons
the distribution of a fiber type in a muscle is due to
the tasks that muscle performs
varies with individuals as well
what is the cell body
cell maintenance, “control center”
the term contraction refers to
the activation of the muscle to produce force (tension)
what is the amount of protein per day
25 to 30 g of protein 3x/day
how many skeletal muscles are in the human body
about 700
a decrease in dopamine causes
slow movement, tremors and rigidity
what is the diameter of the muscle fiber
between 10 and 100 micrometers
what is the break down of muscle components from largest to smallest
muscle, fascicle, fiber, myofibril, sarcomere, myofilaments
what are the two types of neurons in the PNS and CNS
afferent and efferent neurons
what is a myelin sheath
encircles the axon, electrical insulator, increases the speed of neural impulses
where does rigidity occur in PD
typically in limbs
what are some moderate symptoms of AD
difficulty with activities of daily living, such as eating and bathing
anxiety, suspiciousness, agitation
sleep disturbances
wandering, pacing
difficulty recognizing family and friends
what do neurons need to survive
O2 and glucose
what is the smallest functional unit of a skeletal muscle fiber
sarcomere
what is muscle composition
fiber type, fiber size, fiber number, etc
where can you get folate in your diet
dark, leafy greens, citrus fruits, beans/lentils
when the cortex is damaged what is affected
ability to communicate
unable to recognize family members
unable to care for themselves
what changes in size when muscle size changes
change in size of cells
what is a nere
bundle of neurons
treatment for MS
no cure
medications (rilutek/riluzole)
therapy
experimental (stem cell, gene therapy)
what is extension
straitening movement that results in a increase in the angle of a joint
treatment for AD
drug and non-drug
exercise
nutritional supplements
working on vaccine to prevent plaque build up
what are the exercise factors for to help decrease muscle loss
resistance exercise: needs adequate nutrition
high intensity resistance exercise not feasible for certain populations but you can walk and low intensity activity
action potential
a nerve impulse; an electrical charge
what are the three basic principles of the sliding filament theory of muscle contraction
- force is generated as actin filaments slide over myosin filaments
- the lengths of the filaments do not change during contraction
- the length of the sarcomere decreases as the myosin filaments pull the z discs together
what is cytokine production
signaling proteins which trigger inflammation
in MS, the plaques form and destroy what
axons
what are some environmental risk factors for AD
traumatic brain injury
diet: link between diabetes and cardiovascular disease
adequate folate and calcium levels decrease risk
who has a lot of type 2 fibers
football players, weightlifters
a skeletal muscle cell is known as a
muscle fiber
risk factor for sporadic ALS
high levels of glutamate
glutamate found in red meat, processed meat, lunch meat, cheese
neurotransmitter that causes neuron death
a neuron is also called
a nerve cell
abduction
bringing a limb away from the midline of the body
what is akinesia
absence to move at a spontaneous rate
how do neurons function
generate electrical signals that move from one part of the cell to the other and then to other cells
where do plaques first start forming in early stages
forming in areas of the brain used for learning, memory, and planning
what is the rate of progression in ALS
vary
usually 3 to 5 years
some more than 5 or even 10
possible to go into remission but very rare
how does wasting occur
result of inadequate diet
what is static/isometric muscular contractions
no movement occurs
load=tension
holding position to create tension
what is the parasympathetic nervous system
exits brain stem to supply the thorax, abdomen, and pelvic regions
opposite of symp sys because stimulation slows down HR
the amount of tension is related to what
the initial length of the muscle
what are dietary factors to help decrease muscle loss
focus on protein intake
ensure maximum stimulation of muscle protein synthesis occurs at each meal
what is isokinetic muscular contraction
speed of motion remains the same
how is muscle mass determined
by the rates of muscle protein synthesis and muscle protein degradation
do all contractions produce movement
no
does PD have to do more with loss of brain cells or decrease of dopamine
decrease of dopamine
what is cachexia associated with
disease
cant be reversed by nutrition
what is the autonomic nervous system
involuntary control
innervates smooth muscle, intestines, sweat and salivary glands, myocardium, endocrine glands
consist of efferent neurons
what is the force and endurance of pennate muscles
generate a lot of force but not a lot of endurance
how does muscle connect to the bone
tendons
what is hypertrophy
increase in size
purpose of skeletal muscle
responsible for moving the skeleton
supination
rotation of the forearm so palms face up
AD causes
memory loss, problems with thinking and behavior and can cause an impairment in performing everyday activities
symptoms of ALS
muscle weakness
twitching and cramping of muscles (hands and feet)
impairment of the use of the arms and legs (balance issues)
thick speech and difficulty projecting voice
respiratory muscles become affected (ventilation)
sense of sight, touch, hearing, taste and smell are not affected and neither is bladder or eyes
cognitive function is not impaired
what is muscle quality
ratio of strength to mass in upper and lower extremities
functional properties of the muscle (strength, power, etc)
what is one of the body’s communication system
neurons sending electrical signals
alpha one neuron characteristic
larger neuron bc they require a lot of force
does human skeletal muscle undergo hyperplasia
no
what are the two subdivisions of the motor division
somatic and autonomic nervous system
each muscle fiber is surrounded by
endomysium
what is origin
refers to the end of the muscle that is attached to a bone that does not move when the muscle contracts
closest to the heart
during a muscle contraction what happens to myosin and actin
actin moves and myosin stays
what are some normal neurological changes with aging
brain mass slowly declines
slowed thinking and occasional memory lapses
pennation allows for more sarcomeres to be packed into a given area which increases what
force overall
what is the order of brain parts that are affected by AD
hippocampus and amygdala temporal lobe parietal lobe frontal lobe occipital lobe
the ability of fiber types to contribute to force production depends on what
the speed of the movement
how to prevent sarcopenia
physical activity (overload to muscle) diet (adequate protein intake) hormone replacement therapy
what are some characteristics of MS
muscle weakness
fatigue
motor function difficulties
cognitive disability
what is an effector
part of the body effected by a nerve impulse
what type of person is diagnosed with ALS
caucasian
more men
what happens when multiple cross bridges form
create constant tension
what are examples of muscular contraction
eccentric and concentric
what are plaques
abnormal clusters of protein fragments that build up between neurons
what is the length of muscle fibers
can be up to 20cm
what is afferent
sensory neuron, deliver impulse to CNS
alpha 2 neuron innervates what type of fiber
1
what neuron makes up the sensory division
afferent
adduction
bringing a limb closer to the midline of the body
what does dopamine do
the chemical that controls the smooth movement in the human body
communicate from neuron to neuron
what determines muscle fiber type
based on the characteristics of the neuron that controls the fiber
do neurons have longevity
yes
pronation
rotation of the forearm so palms face down
after age 30, adults will lose approx how much of their muscle mass per decade
3-8%
what is cachexia
loss of weight, muscle, and appetite from someone who is not trying to lose weight
what happens to the sarcomere when the muscle contracts
the sarcomere shortens bringing the Z discs closer together
what does sclerosis mean
hardening or scarring from demyelination process
what is insertion
refers to the end of the muscle that is attached to a bone that will be moved when the muscle contracts
furthest from heart
what could be a reason why someone has more of one fiber than the other
genetics
what provides the basis for all human movement
muscular contractions
more people die every year of ALS than
huntingtons disease or MS
can stress help with gaining muscle
no
what are the gaps of myelin sheath called
nodes of ranvier
what is the mean age for ALS diagnosing
65
AD ultimately leads to fewer
neurons in the brain and fewer synapses (less communication)
what do myelin sheath look like
white, fatty segmented substance found on axon
what does the central nervous contain
brain and spinal cord
what is RRMS
relapsing remitting MS
most common form
relapsing, possible acute worsening of neurological functioning, followed by remission with no progression of disease
what diagnostic tests can be used to diagnose MS
MRI scan (can show lesions in brain) Evoked response testing (nervous system response to stimulation) CT Scan (cross section of tissue)
what is the somatic nervous system
conscious control
voluntary muscle
innervate skeletal muscle
consists of efferent neurons
what is hyperplasia
an increase in the number of cells
what are some other functions of the skeletal muscles
site of energy storage and utilization
maintain posture
stabilize joints
generate heat
2 purposes of neurons
to receive incoming information
send a signal to other neurons, muscles or glands
what is the function of myostatin
suppresses the growth of skeletal muscle
what happens with a fully shortened muscle
can’t shorten anymore creating no force of contraction
purpose of cardiac muscle
spontaneous contractions regulated by autonomic nervous system
