Term
| Describe the levels of control of movement by the CNS |
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Definition
Higher centers - cerebral cortex
Middle level - sensorimotor cortex, cerebellum, basal ganglia
Lower level - spinal cord where motor neurons exit |
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Term
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Definition
| an unvoluntary, unvarying response of effector organs to a stimulus (doesn't involve the cerebral cortex) |
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Term
| What are the five fundamental components involved in a reflex? |
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Definition
Sensory cells (receptor)
Sensory nerve fibres
Coordinating center (CNS)
Motor nerve fibers
Effectors (muscle/gland cells) |
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Term
| What is the role of a receptor in a reflex? |
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Definition
| -transduces environmental energy into an AP |
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Term
| What is frequency coding? |
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Definition
| the frequency of APs generated by a receptor cell is proportional to the intensity of the environmental energy being transduced |
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Term
| What is the role of a sensory nerve in a reflex? |
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Definition
conducts the AP from the receptor to
-cell body is in ganglion outside of the spinal cord, enters spinal cord via dorsal roots |
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Term
| What is the role of CNS synapses in a reflex? |
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Definition
-coordinating center
-can be monosynaptic or multisynaptic |
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Term
| What is the role of a motor nerve in a reflex? |
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Definition
| -carries AP from CNS to targeted effectors via ventral roots |
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Term
| Where are the cell bodies of motor nerves found? |
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Definition
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Term
| Where are the cell bodies of sensory nerves found? |
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Definition
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Term
| What are muscle spindles? |
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Definition
| modified muscle fibers with a middle segment which acts as a stretch receptor, will send a reflexive signal to motor neurons to promote contraction |
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Term
| What detects changes in tendon length? |
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Definition
| the golgi organ of tendon cells |
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Term
| Describe the events involved in a tendon reflex |
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Definition
-muscle contracts, pulls tendon
-receptors are squeezed
-sensory nerve contacts inhibitory neuron in spinal cord
-inhibitor motor neurons for the same muscle are stimulated |
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Term
| Describe the action of a knee jerk reflex |
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Definition
-quadriceps muscle contracts in response to tapping of patella ligament
-opposing flexor muscles relax in response to activation of inhibitory motor neurons |
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