100% Verified Answers | Latest Update | Graded A+ |
Assured Pass.
What are the 8 steps of motor control? - --- Answers ---- 1. Premotor
cortex says "I want to do this"
2. Precommand areas provide timing and patterns to execute the
desired movements
3. Basal nuclei are REQUIRED to start movements
4. Cerebellum calculates the best way to perform the action, and sends
information to motor cortex while constantly monitoring
proprioceptive feedback
5. Primary motor cortex sends signals down the direct motor pathways
6. Indirect pathways assist with balance, eye movements, muscle tones
7. Lower motor neurons receive signals from both pathways
8. Sum total of all inhibitory and excitatory signals determines final
response of the lower motor neuron & the skeletal muscles
What are the two types of reflex arcs? - --- Answers --- Inborn and
Learned
What are inborn reflexes and what do they do? - --- Answers --
Unlearned, unpremeditated and involuntary reflexes.
They help us maintain posture, avoid pain and control visceral activities
What are learned reflexes and what do they do? - -- Answers --- Learned
,reflexes are reflexes that come from practice or repetition. They can
modify an inborn reflex by learning and conscious effort.
How is muscle stretch detected? - --- Answers ---- Increased number of
action potentials
why is alpha and gamma coactivation important? - -- Answers ---- the
intrafusal muscle shortens so messages can be sent to tell the brain it
is shortened, while the extrafusal muscle shortens so the muscle can
actually do its job.
How does the stretch reflex work? - --- Answers ---- 1. stretch activates
the muscle spindle
2. sensory neurons synapse directly with alpha motor neurons in the
spinal cord which excite the extrafusal fibers and inhibit motor neurons
controlling antagonistic muscles
3. motor neurons cause the stretched muscle to contract which
resists or reverses the stretch while efferent impulses of alpha
neurons to the antagonistic muscles are reduced.
In stretch reflexes, what pathway has an interneuron? - -- Answers ---
The pathway to the antagonist muscle
How does the tendon reflex work? - --- Answers ---- 1. When a muscle
strongly contracts, the tendon organs are activated.
2. Afferent fibers synapse with interneurons in the spinal cord
,3. Efferent impulses to the muscle with the stretched muscle decrease,
causing muscle relaxation while additionally efferent impulses are
sent to the antagonist muscle, causing it to contract.
What do somatic reflexes target? - --- Answers ---- Skeletal muscle
What do autonomic reflexes target? - --- Answers ---- smooth muscle,
cardiac muscle or glands
What do stretch and tendon reflexes do? - --- Answers --- Help you
smoothly coordinate activity of skeletal muscles
What does the nervous system need to know for stretch and tendon
reflexes and why? - --- Answers ---- length of the muscle, and tension
in the muscles and tendons.
Both of these are important for spinal reflexes, and also give
information to the cortex and cerebellum.
What is the receptive part of the muscle spindle? - -- Answers ---
Central region of intrafusal fiber (no myofilaments here).
What are the two types of afferent nerve endings in muscles and what
do they do? - --- Answers ---- Anulospiral endings: monitor degree and
rate of stretch
Flower spray endings: Monitor degree if stretch only
What stimulates intrafusal fibers to contract? - --- Answers --- gamma
(y) efferent fibers
, What stimulates extrafusal fibers to contract? - --- Answers --- alpha
efferent fibers
Why is the tendon reflex important? - --- Answers ---- Protects against
tearing of the tendon, also allows for a smooth on/off contraction.
How does the flexor and crossed extensor reflex work? - -- Answers ---
A painful stimulus is sent to the spinal cord. This nociceptor synapses
with interneurons which cause the flexor to contract and the extensor
to relax (On the side of pain), all while on the other side, the extensor
contracts and the flexor relaxes.
What does the abdominal reflex check for? - --- Answers --- Integrity of
T8- T12.
What happens if norepinephrine binds to a nicotinic receptor? - --
Answers ---- Stimulation
Where are nicotinic receptors found? - --- Answers ---- all ganglionic
neurons of the SNS & PNS, and adrenal medulla cells
Where are muscarinic receptors found? - --- Answers ---- All PNS
target organs
What happens if ACh binds to a muscarininc receptors - -- Answers --- It
depends. Might be stimulatory, might be inhibitory
What does norepinephrine bind to? - --- Answers --- adrenergic
receptors