Class 7 - Somatic Sensations Flashcards
Somatic sensory pathways consist of sets of __ neurons
3
First order sensory neurons are found in the _____ and travel to the ___
PNS
brain stem & spinal cord
2nd order neurons travel from the ___ to the ___
brain stem and spinal cord TO the thalamus
Which neuron in the 3 neuron pathway decussates?
2nd order neurons
T/F: all somatosensory information from one side of the body reaches the same side of the thalamus.
False
Where are 3rd order neurons found and where do they travel to?
in the thalamus, to the primary somatosensory area of the cortex on the SAME SIDE
The postcentral gyrus is found in the ___ lobe and contains the ____
PARIETAL, primary somatosensory area
The thalamus is joined by the ___ in 70% of brains
interthalamic adhesion
Which sense does NOT travel through the thalamus?
olfaction
Axons between the thalamus and cortex pass through the…
internal capsule
The ventral group nuclei function in ____
movement control
The midline thalamic nuclei plays a role in…
memory and olfaction
The anterior, medial and lateral thalamic nuclei all are involved in…
emotional memory
Which of the posterior column nuclei is responsible for the lower limb & trunk?
gracile nucleus
The posterior column neurons decussate ____ entering the medial lemniscus
BEFORE
What sensory information is relayed by the spinothalamic tracts?
pain, temperature, crude touch, itch & tickle
What are the epicritic sensations?
discriminative touch, pressure, vibration, conscious proprioception
Where does the spinothalamic tract decussate?
near where it enters the spinal cord, before ascending
The lateral spinothalamic tract is responsible for _____ and ____
pain and temperature
The 1st order neuron of the trigeminothalamic pathway has its body found in the ____
trigeminal ganglion
Where do the 1st order axons of the trigeminothalamic pathway synapse with 2nd order neurons?
in the pons OR they will descend to the medulla oblongata to synapse there
Where is the trigeminal nuclei?
in the pons and medulla
Where is the cell body of 2nd order trigeminothalamic pathway neurons?
in the trigeminal nuclei
True or false: trigeminothalamic 2nd order neurons will decussate in the ___ and then synapse with 3rd order neurons in the opposite side thalamus.
fix
Where are the anterior & posterior spinocerebellar tracts found?
lateral white matter of spinal cord
Bowman’s glands are found in the ___ and produce ____
olfactory epithelium
mucus to dissolve odorants
Olfactory cells have a ___ lifespan
1 month
Supporting cells & olfactory glands are innervated by the…
facial nerve
Olfactory receptor cells are ___ neurons (structural type) that synapse with 2nd order neurons in the olfactory bulb.
bipolar neurons with a bare dendrite
Olfactory receptors adapt by __% in the first second and __ thereafter
50%
slowly
Complete insensitivity to some strong odors can occur in about __ after exposure
1 minute
The olfactory nerves are a bundle of about __ unmyelinated axons from the olfactory receptors
40
The olfactory nerve (CN I) is the __ order neuron in the olfactory pathway
1st order`
Where is the primary olfactory area found in the brain?
inferior & medial surface of temporal lobe AND limbic system
True or false: the special senses have 3 order neuron pathways
FALSE
Meibomian glands purpose is to…
prevent the eyelids from sticking to each other
Infection of a meibomian gland is called a…
chalazion
The bulbar conjunctiva extends from the…
eyelid to anterior eyeball, NOT covering the cornea
