Midterm 1 Flashcards
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What is a Homeostatic response
a body RESPONSE to get back to a resting or steady state
Is getting hot while you exercise a homeostatic or allostatic response
homeostatic; it is a response
What is a Allostatic resopnse
an ANTICIPATORY reaction to an activity
Is heart rate increasing before exercise a homeostatic or allostatic response
allostatic; it is an anticipation
What is the function of the Cerebral Cortex?
-Language
- reasoning and abstract thinking
- sensory and voluntary motor control
What is the function of the Basal Ganglia
- initiates and controls movements
- makes movement efficient
- cognitive, emotions and movements
- addiction and dopamine
What’s the function of the Hypothalamus
-metabolism and temperature
- cardio vascular/respiratory rhythm (ans)
-sleep
What’s the main functions of the limbic system
-processing and interpreting sensory info
- neurotransmitters release
-better mood and pain
-motivation
- stress
What parts makes up the brain stem
-midbrain
-pons
-medulla oblongata
What is the function of the brain stem
- connect neurons to spinal cord
- nuclei have cardiac and respiratory functions (thermoregulation)
-reduces vagal tone
-symp nerve activation
What is the function of the cerebellum
-body posture and equilibrium
-receives sensory info from afferents
- sends info to thalamus (then cerebral cortex)
What is the difference between efferent and afferent nerves
-Efferent> Motor
- Afferent> Sensory
What is an Interneurons role?
middle man to connect sensory and motor neurons
What ratio contributes to variation in motor skills?
Motor Neuron-Muscle fiber ratio
What is the All or None Principle?
all the muscle fibers innervated in a motor neuron are simulated to contract
What is the Motor Unit Size Principle?
there is an anatomic basis that determines the order of motor units to produce smooth muscle action
What’s an Action Potiential?
-wave of depolarization
- made by changes in membrane potential
What are the 3 Action Potential Stages
- Depolarization (Na+ entering)
- Repolarization (K+ leaving)
- Ions returning with Na+/ K+ pumps
What do Nodes of Ranvier do?
-ion diffusion in and out of neuron
What do Myelin Sheaths do?
- protect axons
- faster node transmissions
Explain how skeletal muscle contracts
- Vesicles in terminal axon release ACh > attach to receptors in sarcolemma
- Receptor depolarizes > t-tuble causes Ca release
- Ca binds to troponin-tropomyosin in actin> inhibition of actin with myosin
- Actin+myosin ATPase makes ATP to produce crossbridge movement
- muscle shortens, bond breaks, sliding filaments
- when Ca is high crossbridge is activated, Ca moves back, everything moves back
What order do muscle fibres innervate?
I > IIa > IIx
Explain the characteristics of Type I fibres
-Slow
- Low Force
- Slow cotract speed
-high fatigue resistance
-no sag
- Slow Oxidative fibre
Explain the characteristics of Type IIa fibres
- Fast- fvatigue resistant
- moderate force
- fast contraction
- moderate fatigue resitance
-yes sag - fast oxidative glycotic
Explain the characteristics of type IIx fibres
- Fast Fatigable
- High force
-fast contraction - low fatigue resistance
-yes sag
-fast glycolytic
What is Motor Unit Recruitment
Increasing the number of motor units recruited
What is Motor unit rate coding
Increasing the frequency of motor unit discharge
What do muscle spindles do
- responds to any stretch of muscle
- provides info about changes in fibre length and tension
- increase the level of muscle contraction
What do nuclear bag fibers do
- in muscle spindles
- respond to phasic stretch
what do nuclear chain fibers do
- in muscle spindles
- respond to static stretch
What do golgi tendon organs do
- respond to tension from CONTRACTION
- protective mechanism (sensory)
- reduces level of muscle contraction
Explain the stretch/ myotatic reflex
- involuntary contraction from fast muscle stretch
-reflex arc> two nerves and one synapse - helps to maintain body balance
- happens even when standing still
what is the shape of the length-tension curve
exponential
What determines the length tension curve
- number of cross bridge formations
- enviromental conditions (pH, ATP, Ca)
What makes an isometric contraction
amount of overlap depend on length of muscle before activation
What makes a shortening contraction
sliding movement makes myosin be overlapped by actin
what makes a lengthening contraction
crossbridge has less tension than stretching force. actin and sarcomeres are pulled away from each other
Explain the Popping Sarcomere Hypothesis
-extension of individual half-sarcomeres
-weakest to strongest
- sarcomere stretched until passive tension can support the tension and sarcomere is popped
Why do we experience muscle soreness
- group iii fibers (afferents) respond to deformation and intramuscle substance which cause pain
-they project to the CNS and promote pain and muscle soreness
What is the shape of the force-velocity curve
Hyperbolic
what is the shape of the power curve
Parabolic
What’s the role of velocity and force in power production
- force and velocity are inverse
-increase in muscle shortening(V) causes force to decrease
-isometric (0 V) there is max force
What is optimum force and velocity
P=F*V
around below 50% of max values for each
T/F: sarcomere in series and in parellel produce the same work, power potential and force
False. They only produce the same work and power potential.
What are the advantages of sarcomeres in series vs in parallel
Parallel: force production
Series: Velocity and Displacement
Whats the difference between Anatomical (ACSA) cross section area and Physiological (PCSA) cross section area
ACSA: largest cross sectional area along the length of the muscle
PCSA: total cross section area of all fibers with a muscle
What are the 3 training principles
- Individuality
- Specificty
- Reversibility
What is exercise volume
the amount of work done in a workout
What is the progressive loading principle
the workout gets more difficult over time
What are the results of progressive overloading in different populations
- limited progress in elite weight lifters
- any method with work in untrained individuals
- adaptations are limited in clinical populations
In resistance training, changes in muscle strength and power is due to:
-neural adaptations
-muscle hypertrophy
in untrained individuals, the influence of strength training can be seen as an increase in _____ to muscles. It is then followed by increase in ________, and this ______ effect may be more pronounced in _____ fibres
- neural activation
- Muscle fibre size
- hypertrophic
- fast twitch
Explain Neural Control of Strenght Gain
- greater # of motor units will activate at a time
- rest>sub max>MVC before training> MVC after training
- reduce of contract inhibition in golgi
- inhibit antagonist increases agonist
What is cross education
an increase in strength is witnessed within an untrained limb following unilateral strength training in the opposite, contralateral limb
What mechanisms determine cross education
increase of central motor output to the muscle
