sensory (afferent) division inputs info into..
brain and spinal cord (control centres)
brain and spinal cord integrate info and control effectors though..
motor (efferent) division (output)
Reflexes on the spinal cord
rapid automatic response to stimuli, always causes the same motor response, usually protective and involves 2 or more neurons
Reflex pathway or arc =
pathway of impulses
Reflexes are categorized according to..
- effector
- which sides of the boys the sensory and motor neurons are located
- number if synapses and neurons in arc
2 ways reflexes are sorted by effectors
- somatic reflex= effector is skeletal muscle
- visceral (autonomic) reflex - effector is smooth muscle, cardiac muscle or glands
2 ways reflexes are sorted by which sides of the body the sensory and mother neurons are located
- ipsilateral reflex = sensory and motor neurons are on same side
- contralateral = sensory and motor neurons are on opposite sides
2 ways reflexes are sorted by number of synapses and neurons in arc
- monosynaptic reflex = one synapse between 1 sensory and 1 motor neuron
- polysynaptic reflex= 2 or more synapses between 3 or more neurons
3 somatic spinal reflexes
- stretch reflex
- flexor reflex
- crosses extensor reflex
Stretch reflex
ex: knee jerk reflex. extensor muscle contacts. ipsilateral, monosynaptic
- stimulus= tapping patellar ligament, which stretches the quadriceps fears muscle
- receptor= muscle spindle
- effector- skeletal muscle contacts
Flexor reflex
ex: in leg ipsilateral, polysynaptic -stimulus= stepping on nail -receptor= touch, pressure, pain -effector= hamstrings contacts
Crosses extensor reflex
ex: in leg
contralateral, polysynaptic, keeps you from falling
-stimulus= stepping on nail
-receptor= touch, pressure, pain
-effector= quadriceps femoris in opposite leg contacts
Reciprocal inhibition
skeletal muscle (or group) contracts (agonist), at same time, antagonist prevented from contracting.
Example of reciprocal inhibition
stretch reflex
- quadriceps femoris (agonist) contacts
- hamstrings (antagonist) contraction inhibited
Autonomic spinal reflexes
effector = smooth muscle, cardiac muscle or glands
Example of autonomic spinal reflexes
micturition reflex- urinary bladder
- stimulus = stretch of the bladder
- receptor = stretch receptors in the bladder wall
- CNS = sacral segment of spinal cord (PSNS)
- effector= detrusor muscle contacts and internal urethral sphincter opens (both smooth muscle)
Cerebrums 4 tasks
- interpreting sensory info from general and special sense
- initiating and controlling skeletal muscle movement
- memory, intellect
- relaying info between different parts of the brain and/or spinal cord
Brain stem
- controls life sustaining processes
- if brain stem functional but high centres damaged then your alive but not aware, no conscious control
3 parts of the brainstem
- midbrain
- pons
- medulla oblongata
Midbrain
auditory and visual reflexes, movement of eyes, had, and neck in response to stimuli
Pons
functions with medulla to regulate breathing
3 functional regions of the medulla oblongata
- decussation of sensory and motor tracts
- autonomic vital reflex centres
- other non vital areas
Decussation (crossing) of sensory and motor tracts
left brain controls right skel. muscles, receives sensory input from right side
2 Autonomic vital reflex centres
- respiratory area (drives breathing rate
- cardiovascular centre (cardiac area= heart rate) (vasomotor area= controls blood vessel diameter)
