anatomy somatic nervous system study for test 2

somatic nervous

general sensations (skeletal muscles)

autonomic

smooth muscle, cardiac tissue, and glands

sensation

arriving information(whether or not you know it)

perception

Conscious awareness of sensation

would you feel a spider moving up your back if so why

yes, because it would trigger hair receptors

How are receptors classified?

by modality (what kind of stimulus , by origin(where stimuli occurs), specificity(the sensitivity), and adaptation (reduced sensitivity by constant stimulus)

what is the area monitored by a single receptor

receptive field

which field has a better discrimination of pain

small receptive field

what information is transmitted by nueral pathway for stimulus

the type and location of stimulus

what information is transmitted by the action potential frequency

strength and duration of stimuli

phasic receptors

Normally inactive but become active for a short time when a stimulus activates receptor which then quickly adapts (smell and hair receptors)

tonic receptors

always active and generate impulses continually and adapt slowly(pain and proprioceptors)

where are the types of receptors processed

brainstem or spinal cord

nociceptors

pain receptors

is nociceptors tonic or phasic and can they adapt

tonic and cannot adapt but CNS can reduce pain sensation

someone has a heart attack and also feels pain in left arm not just chest

referred pain

how can pain perception be reduced and exaggerated

by endorphins and nuerotransmitters

does eating spicy food stimulate both chemoreceptors and thermoreceptors

yes

thermoreceptors phasic or tonic?

phasic

what are the 3 types of mechanoreceptors

tactile, baroreceptors, proprioceptors

what causes mechanoreceptor ion channels to open

pressure, stretch, or vibration

tactile receptors

touch and vibration in the epithelia

baroreceptors

detect changes in blood pressure and adapt rapidly

proprioceptors

monitor tension and position of joints mostly done without thought

chemoreceptors

detect change in PH, CO2, O2 in the blood and happens autonomic

gray matter

cell bodies of neurons and unmyelinated axon in "butterfly"

white matter

bundles of axons outside of gray matter

descending motor tracts

are motor instructions to outer body processes

ascending motor tracts

carry sensory information to brain

1st order neuron

sensory neuron detects a stimulus and transmits a signal to the CNS

2nd order neuron

receives signal from 1st order, is found in the brain stem and spinal cord, may crossover or decussate it CNS before going to thalamus

how many parts of ascending sensory tract

3

3rd order neuron

located in the thalamus and projects to the cerebral cortex, where perception of the sensory stimulus occurs

what does the cuneate /gracile fascicules tract carry

deep touch and visceral pain from upper limbs, chest, and proprioception of lower limbs

cuneate/gracile fasciculus tract order

goes from sensory neuron to medulla oblongata and then decussates to other side of the medulla then goes to the thalamus and finally goes to the cerebral cortex

spinothalamic tract carries what

light touch, pain, temp, tickle, itch, and pressure

order of spinothalamic tract

somatic receptors to spinal cord and decussates and then goes to thalamus and then to cerebral cortex for awareness

what is phantom limb pain

Pain felt in an area that has been amputated due to the brain still being able to process signals as if the limb were still there

spinocerebellar pathway carries

proprioception from muscles, tendons, and joints

spinocerebellar pathway

sensory neuron to spinal cord and then may decussate and then goes to cerebral cortex

primary somesthetic cortex

found in the postcentral gyrus and conscious sensation is processed here

Why do the hands and lips have a larger representation in the Primary somesthetic cortex compared to the back or legs?

They have more sensory receptors

primary motor cortex where and what does it do

precentral gyrus and conscious movement is controlled here

Why do some body parts have a bigger area in the primary motor cortex?

Body parts that require more precise control, like the hands and face, have a larger area in the primary motor cortex

general organization of motor pathway

from the upper motor neuron to the lower motor neuron that then excites or inhibits the muscle but the upper motor neuron controls if this occurs

what is ALS

a disease that destroys motor neurons, causing muscle weakness, paralysis, and eventually respiratory failure.

What is poliomyelitis?

viral disease received from polio that destroys spinal motor neurons, leading to muscle weakness and paralysis(similar to ALS but much quicker moving)

corticospinal tract

rapid conscious control of limbs and finely coordinated movements, the UMN synapses with LMN in the brain or spinal cord

tectospinal tract

controls subconscious reflexive head movements in response to noise

reticulospinal tracts

tract originates in the reticular formation and has control of upper and lower limbs to maintain posture

what can the vestibulospinal tract do if PMC is damaged

can compensate and control movement but will be awkward

how does coordination by the cerebellum work

monitors proprioceptive, visual, vestibular sensations and adjusts UMN by comparing to previous movement

what is a nerve

a bundle of axons

what are ganglia

neuron cell bodies

What is a nerve plexus, and where are they found

network of interwoven spinal nerves. They are found in the cervical, brachial, lumbar, and sacral regions, supplying the skin and muscles of the limbs and trunk

why do we not do shots near the armpit

it is closer to the brachial plexus and contains many nerves