Flashcards in Physio II Lecture 4 Deck (70):
the Primary somatosensory are is made up of?
Brodmann's Areas 1, 2, & 3
the Somatosensory ASSOCIATION area is made up?
Brodmann's areas 5 and 7
Bilateral excision in Somatosensory area I results in Astereognosis. A term that describes one's loss of ability to do what?
judge shapes or forms
a Bilateral cut in the Somatosensory area I will preserve these senses but they will be poorly localized
Pain and Temperature
Removal of somatosensory II has no apparent effect on the response of neurons in?
Somatosensory area I
The somatosensory area II (SSAII) receives signals from?
1. Brain stem, transmitted Up and bilaterally2. secondarily from SSAII (somatosensory area II) 3. Visual, Auditory, and other sensory areas
these layers of the Somatosensory cortex send information through the corpus callosum to the opposite hemisphere
layers II and III
the Superficial layers of the SS cortex function in?
receiving input signals from lower brain centers
Axons from layer VI in the SS cortex project into this part of the Brain
large neurons from this layer in the SS cortex project to distant areas such as basal nuclei, brain stem, and spinal cord
Receptor potentials are created in response to membrane deformation caused by touch or pressure that will open these channels
Modality gated sodium channels
if the receptor potential is strong enough, through Summation, it may generate an action potential at the first?
Node of Ranvier on the primary sensory neuron
Primary neurons are?
first order neurons. they originate from peripheral receptors and enter the spinal cord or brain via Dorsal roots of spinal/cranial nerves
Primary neurons synapse in the spinal cord with?
the cell bodies of Primary neurons are located in the?
Dorsal root ganglia
these neurons originate in spinal cord gray matter, travel through myelinated columns in the spinal cord, decussate, and synapse in the thalamus with Tertiary neurons
Tertiary neurons travel through internal capsule, which is a myelinated pathway between thalamus and basal nuclei, to synapse in?
the somatosensory cortex
this touch refers to the ability to distinguish two separate points as close as 2mm apart.
two Point discrimination travels in the?
Dorsal column-medial lemniscal pathway
why is Lateral inhibition important in the Cerebral cortex?
blocks the lateral spread of excitatory signals, thereby increasing the degree of contrast in the cerebral cortex
Lateral inhibition occurs at these three sites
Dorsal Column nuclei
Ventrobasal nuclei of thalamus
Peripheral sensory neurons originate from?
receptors in the periphery
the Dorsal Column-medial lemniscal pathway also carries these neurons
Axons from the lower limbs travel in the medial portions of the two dorsal columns called the?
axons from the Upper limbs travel in the lateral portions of the two dorsal columns called the?
axons in the fasciculus gracilis synapse in the lower medulla in the?
axons in the fasciculus cuneatus synapse in the lower medulla in the?
Secondary neurons travel through the brain stem as paired tracts referred to as the?
Secondary neurons synapse in this part of the brain with Tertiary neurons
basolateral nucleus of the Thalamus
Decussation occurs with these neurons
primary sensory neurons travel (up/down) through dorsal columns of spinal cord into (upper/lower) Medulla and synapsing with _____ in the nucleus gracilis and the nucleus cuneatus of the medulla
Secondary neurons ascend up the brainstem to the?
tertiary neurons synapse with secondary neurons in the Thalamus and travel to?
Nociceptors are what type of receptor
Fast pain is carried by?
A-Delta pain fibers
A-delta pain fibers typically terminate in____ of the dorsal horns of the spinal cord
Lamina I marginalis
Slow pain is carried by?
C type fibers
This type of pain is described as aching, slow burning, throbbing, nauseous, and chronic
Slow pain terminates in____of the dorsal horns of the spinal cord
Layers II and III (Substantia gelatinosa)
Nerve fiber type C is classified as sensory nerve? and associated with this motor function
which path does Pain travel?
anterolateral pain pathway is made up of?
Secondary fibers that decussate
fast pain fibers make up these tracts and synapse/terminate in the Ventrobasal nuclei of the Thalamus
slow pain fibers make up this pathway
A-delta fibers of the fast pain path use this amino acid as their Neurotransmitter
where do most paleospinothalamic secondary fibers terminate?
throughout the brain stem, but some pass all the way to the thalamus.
C type slow fibers release substance P faster than Glutamate. T or F?
false, substance P is released more slowly while Glutamate acts instantaneously
What occurs as the result of a Hemisection of the spinal cord?
All ____ functions are blocked on the side of the transection in all segments (above or Below) the level of the transection
In Brown-Sequard Syndrome, which sensations are lost?
pain, heat, and cold in the Spinothalamic pathway are lost on the opposite side of the body in Dermatomes 2-6 segments below the transection level.
Can you lose two-point discrimination in Brown-Sequard Syndrome?
yes, on the side of the transection in all dermatomes below the transection
Periaquaductal Gray and Periventricular regions of Brainstem and third ventricleRaphe magnus nucleus and reticular nuclei in MedullaPAIN inhibitory complex in dorsal horns of spinal cord.are three major components of this System
The Analgesia System
What type of neuron is from the Nucleus raphe magnus?
What are the three types of receptors that Discriminate thermal gradations
cold, warmth, and Pain
Warmth nerve endings are mainly transmitted by?
C type Fibers
Cold receptors are more numerous than warm nerve receptors and transmitted by?
small, type A-delta myelinated endings.
Thermal signals are transmitted in pathways parallel to?
cold and warmth receptors are thought to be stimulated by changes in?
Heat pain receptors kick in around 45 degrees celsius and send how many impulses per second?
cold receptors stop sending signals at what temp?
right before heat pain receptors kick in. ~45 celsius
this pain type occurs when visceral pain fibers are stimulated and stimulate some of the pain fibers that conduct pain signals from the skin.
All visceral pain from the Thoracic and abdominal cavities is transmitted by?
C type pain fibers
Severe Referred pain results when there is diffuse stimulation of pain nerve endings throughout the viscera caused by such things as?
Ischemia- a restriction of blood supply to tissues. usually from thrombosis and can lead to Myocardial Infarction (heart attack) or Cerebrovascular attack (Stroke)
Ascending tracts are designated on which side?
descending tracts are designated on which side?
Spinothalamic is a descending or ascending tract?
ascending. going from the SPINE to the Thalamus. see the word roots? should help you figure it out.
the result of pain referred to the surface of the head from deep head structures are called?
The Brain is Insensitive to pain. True or False
true. so don't poke it! the reason why Brain surgery is performed while the patient is under a light Anesthesia for the skin and skull
What are the three areas of Headache?
Cerebral VaultNasal sinus and eyeBrain stem and Cerebellar vault