Term
| Muscle spindles are located in ____________ with muscles fibers while ________ ________ are located in series. |
|
Definition
|
|
Term
| Primary afferent fibers of the muscle spindle respond to what two things? |
|
Definition
| Stretch of regular fibers and contraction of the ends of the intrafusal fibers |
|
|
Term
| Stimulation of muscle spindle primary afferent fibers results in _________ of the motor neurons to the same muscle and _________ of antagonist muscles. |
|
Definition
|
|
Term
| In muscle spindles, gamma motor neurons receive input from descending motor systems and _______ ________ to exert influence over the stretch reflex. |
|
Definition
|
|
Term
| The muscle spindle (Ia) exerts negative feedback to maintain muscle _______ while golgi tendons (Ib) maintain muscle _________. |
|
Definition
|
|
Term
| Which of the following is true regarding the flexor withdrawal reflex - there is polysynaptic excitation of agonist muscles, polysyn inhibition of antag muscles, and an opposite pattern on the contralateral side leading to a crossed extension response. |
|
Definition
|
|
Term
| This neurological pathway conveys proprioception, touch, pressure, and vibration sense from the body to the cerebral cortex. |
|
Definition
| Ascending pathway - dorsal column/medial lemniscal pathway |
|
|
Term
| This neurological pathway conveys sensations of pain, temp, and crude touch from the periphery to the cortex and includes the spinothalmic path. |
|
Definition
|
|
Term
| This descending neurological pathway is involved in facilitatory effects on flexor muscles, skilled movements of the digits, and is concerned with voluntary movements. |
|
Definition
| The lateral corticospinal tract |
|
|
Term
| How does nicotine enhance excitatory synaptic transmission? |
|
Definition
| By activating presynaptic Ca channels |
|
|
Term
| What neurotransmitter is used for fast synaptic transmission in the CNS and what are its 3 receptors? |
|
Definition
| Glutamate; AMPA, KA, NMDA |
|
|
Term
| What is the role for glutamate’s 3 receptors? |
|
Definition
| AMPA- responsible for transmission at most excitatory synapses, KA- they slow postsynaptic potentials and modulate presynaptic transmission, NMDA- Ca permeable Glu receptors and require glycine as co-agonist |
|
|
Term
| What is the difference in neuron control of Cl concentration in young versus old cells? |
|
Definition
| Young cells have high Cl concentrations and opening of GABA receptors causes a loss of Cl and depolarization, whereas the opposite is true for mature cells |
|
|
Term
| What is the difference between the two theories or types of GABA-A mediated inhibition? |
|
Definition
| Phasic says that GABA receptors are stimulated by quantal packets of transmission whereas Tonic says that there is a basal tone that is modulated by GABA transmission |
|
|
Term
| What is the effect of benzos and barbiturates on GABA receptor function? |
|
Definition
| They potently enhance its function |
|
|
Term
| How does low dose ethanol affect GABA receptors? |
|
Definition
| It enhances tonic inhibition |
|
|
Term
| What is a depolarization-induced suppression of inhibition? |
|
Definition
| There is a retrograde synaptic transmission from the postsynaptic neuron caused by increased levels of calcium that inhibits pre-synaptic release of calcium and therefore GABA; endocannabinoids are one such retrograde transmitter |
|
|
Term
| What is spinal shock following a spinal chord injury? |
|
Definition
| Depression of spinal reflexes accompanying a rostral spinal chord injury in phase 1, followed by hypersensitivity in phase 2, then hyperreflexia in phases 3 and 4 |
|
|
Term
| Which of the following occur when a spinal chord injury occurs between the pontine micturition center and the sacral spinal chord causing urinary dysfunction - bladder hyper-reflexia, detrusor-sphincter dyssynergia, poor detrusor contraction, increased post-micturition volume? |
|
Definition
|
|
Term
| After a patient has a spinal chord injury, why is the presentation of autonomic dysreflexia a medical emergency? |
|
Definition
| Because its an acute syndrome of excessive sympathetic output triggered by distended bladder, UTI, constipation or tight fitting clothes |
|
|
Term
| Which of these are components of the BBB- Microvascular endothelial cells, basement membrane, astrocyte end feet, perictyes? |
|
Definition
|
|
Term
| What is the importance of the P-glycoprotein efflux pump? |
|
Definition
| It reverse transports certain classes of drugs out of the brain resulting in reduced efficacy |
|
|
Term
| What is significant about the area postrema other than it sits outside the blood-brain barrier? |
|
Definition
| It houses the Chemotrigger zone at the base of the 4th ventricle that causes emetic effects when stimulated |
|
|
Term
| What 3 nuclei are in the vomiting center (medulla)? |
|
Definition
| Nucleus tractus solitarius, dorsal motor nucleus, and nucleus ambiguous |
|
|
Term
| Why is fluorodeoxyglucose used in PET scans? |
|
Definition
| It is transported to tissues via the glucose transporter and accumulates in tissues proportionate to metabolic activity |
|
|
Term
| What molecule is used as a tracer for various drugs in PET scans? |
|
Definition
|
|
Term
| If there is damage to the Edinger-Westphal nucleus what clinical findings do you see? |
|
Definition
| Papillary dilation and lack of papillary light reflex. |
|
|
Term
| Where do the lateral and medial motor pathways of the brainstem exert their greatest influence? |
|
Definition
| Lateral - flexor muscles, fine control, upper limbs; Medial - extensor muscles, postural |
|
|
Term
| The rubrospinal tract originates in the magnocellular region of the red nucleus, what motion does it facilitate? |
|
Definition
| Flexors of the upper limb |
|
|
Term
| How does the lateral and medial reticulospinal tracts influence extensor muscles? |
|
Definition
| The lateral tract inhibits extensor muscles while the medial tract facilitates them |
|
|
Term
| How do lesions above and below the red nucleus present differently? |
|
Definition
| Above - decorticate spasticity, flex upper and extend lower limbs; below - decerebrate spasticity, extension of body and all limbs |
|
|
