Flashcards in # 5. Spinal cord physiology Deck (26):
What are the 2 main functions of the spinal cord?
1. propagate nerve impulses (white matter)
2. integrates information (grey matter)
What are the 2 main sensory tracts?
1. spinothalamic tract
2. posterior column
What does the spinothalamic tract do?
conveys nerve impulses fro sensing pain, termperature, itch, tickle and deep pressure
What does the posterior column do?
conveys nerve impulses for touch, light pressure, vibration and conscious proprioception
Which to tracts make up the posterior column?
1. gracile fascilicus
2. cuneate fascilicus
What is conscious proprioception?
the awareness of the positions and movements of muscles, tendons, and joints
what are the 2 main motor tracts?
1. directs pathways
2. indirect pathways
What are the direct motor pathways?
-lateral corticospinal tract
-anterior corticospinal tract
What do the direct motor pathways do?
-convey nerve impulses that originate in the cerebral cortex
-causes voluntary movements of skeletal muscles.
What are the indirect pathways?
-lateral reticulospinal tract
-medial reticulospinal tract
What do the indirect pathways do?
-convey nerve impulses the originate in the brain stem
-cause automatic movements
-sustain contraction of postural muscles
a change in the internal or external environment
a fast involuntary, unplanned sequence of actions that occurs in response to a particular stimulus; can be inborn or learned
What are the four types of reflexes?
-autonomic (visceral) reflexes
Where does the integration happen in a spinal reflex?
in the grey matter of the spinal cord
Where does the integration happen in the cranial reflex?
in the brain stem
What is a somatic reflex?
involves contraction of skeletal muscles
What are autonomic reflexes?
not usually consciously perceived.
-involves responses of smooth muscle, cardiac muscle and glands.
What is a reflex arc (reflex circuit)?
the pathway for a nerve impulse to produce a reflex
What makes up the reflex arc? (pg. 462 in new A&P text)
1. sensory receptor
2. sensory neuron
3. integrating center (located in the CNS)
4. motor neuron
What is a sensory receptor?
-the distal end of a sensory neuron (dendrite) or an associated sensory structure
What are the two types of reflex arcs that can occur in the integrating center?
-monosynaptic reflex arc
-polysynaptic reflex arc
What is a monosynaptic reflex arc?
-the most simple
-a reflex pathway with only one synapse in the CNS
-involves 2 neurons (the sensory neuron going in and the motor neuron going out) and 1 synapse
What is a polysynaptic reflex arc?
-when the integrating center consists of at least one interneuron
-involves more than 1 synapse in the CNS
-involves 3 neurons (one sensory going in, one interneuron to relay message, and one motor neuron going out) and 2 synapses.
What is the effector in a reflex arc?
the part of the body that is responding to the nerve impulse
(ie. the muscle or gland)