Neuro - Pain 3

Nociceptive fibres terminate in the ____ of the spinal cord

dorsal horn

Neurons in lamina 1 of the dorsal horn receive direct input from ___ nociceptive fibres and both direct and indirect input from ___ nociceptive fibres in lamina 2.

A delta; C

True or False: Lamina 5 neurons receive low-threshold input from large-diameter myelinated fibres (Aβ) of mechanoreceptors as well as inputs from nociceptive afferent fibres (Aδ, C)

true

Lamina 5 neurons send dendrites to lamina 4, where they are contacted by the terminals of ____ primary afferents

A Beta

True or False: Dendrites in lamina 3 arising from cells in lamina 5 are contacted by the axon terminals of lamina 2 interneurons

true

True or False: Aα fibres innervate motor neurons and interneurons in the ventral spinal cord

true

Lamina 5 neurons project to...

brain stem and thalamus

Convergence of visceral and somatic afferent fibers may account for _____

referred pain

True or False: Nociceptive afferent fibers from the viscera and fibers from specific areas of the skin converge on the same projection neurons in the dorsal horn

true

True or False: The terminal of a C fibre on the dendrite of a dorsal horn neuron has two classes of synaptic vesicles that contain the same transmitters

false

Small electron lucent vesicles contain ______

glutamate

Large dense-cored vesicles contain _____

neuropeptides

substance p

SP

True or False: Neuropeptides and glutamate oppose each other to regulate firing properties of secondary neurons in dorsal horn

false

The neurokinin 1 (NK1) receptor is found throughout the spinal cord but is present at the highest concentration in which lamina?

lamina 1

Sensation of pain travels from its origin to the brain via the ______ system, crossing the midline in the spinal cord before ascending to the thalamus

spinothalamic

anterolateral

True or False: Pain descends the spinothalamic system to reach the brain

false

The anterolateral (spinothalamic) pathway transmits information on (blank); while the dorsal column pathway transmits information on (blank)

pain and temp; mechanosensory

The spinothalamic system is also called the ___ system

anterolateral

True or False: Primary afferent pain fibres of the anterolateral pathway synapse on second order neurons as soon as they enter the dorsal horn

true

True or False: Lamina 1 and 5 secondary neurons immediately cross the midline (decussation)

true

Mechanoreceptor primary neurons of the dorsal column pathway synapse in the ____

medulla

True or False: Secondary neurons of the dorsal column pathway in the medulla cross the midline and ascend to the contralateral thalamus

true

True or False: Mechanoreceptor primary neurons synapse when they get into spinal cord

false

True or False: The anterolateral system crosses and ascends in the contralateral anterolateral column of the spinal cord, while the dorsal column system ascends in the ipsilateral dorsal column

true

A lesion restricted to the left half of the spinal cord results in dissociated sensory loss and mechanosensory deficits on the ___ half of the body, with pain and temperature deficits experienced on the ____.

left; right

With a lesion in the spinal cord, you would expect a loss of mechanosensation on the ____ side of the body, and a loss of pain and temp on the ____ side of body as compared to the lesion

same; opposite

True or False: Descending monoaminergic pathways regulate nociceptive relay neurons in the spinal cord

true

A serotonergic pathway arises in the _____ and projects through the dorsolateral funiculus to the dorsal horn of the spinal cord

nucleus raphe magnus

A noradrenergic pathway arises in the ____ and other nuclei in the pons and medulla

locus ceruleus

Both the sertonergic nucleus raphe magnus and noradrenergic nuclei receive input from neurons in the _____ region

periaqueductal gray

periaqueductal grey

Serotonergic (Serotonin) and noradrenergic (NE) neurons in the brainstem _____ the local interneurons and _____ the activity of the spinothalamic projection neurons

activate; suppress

Enkephalins and ______ are endogenous opioids that act at opioid receptors and their activity can be blocked by opioid antagonists

endorphins

Activation of a nociceptor leads to the release of glutamate and neuropeptides from the primary sensory neuron, producing an (excitatory or inhibitory) postsynaptic potential in the projection neuron

excitatory

Do opiates depolarize or hyperpolarize the dorsal horn neurons?

hyperpolarize

True or False: It is disputed as to whether or not the placebo affect is valid

false

Opiates close ___ channels and open ___ channels (Use the chemical symbols)

Ca; K