neural system Flashcards
central nervous system (CNS)
brain
spinal cord
peripheral nervous system (PNS)
cranial nerves- 12 pairs
spinal nerves - 31 pairs
- brain to effectors
- effectors to spinal cord
afferent nerves
- sensory neurons
- impulses from receptors to CNS
efferent nerves
- motor neurones
- impulses from CNS to effectors
the brain
cerebrum- 4 lobes (frontal, parietal, temporal and occipital)
cerebellum- little brain (coordinating movement by cerebral cortex)
diencephalon- thalamus, hypothalamus, pituitary gland (sensory integration and homeostasis regulation)
brain stem- connects brain to spinal cord (CV and respiratory control)
cranial nerves (12 pairs)
- nose, smell - sensory
- eye, vision - sensory
- upper eyelid and eyeball - motor
- movement of eyeball - motor
- touch, pair, chewing - sensory/motor
- eyeball movement - motor
sensory neurones
baroreceptors
chemoreceptors
mechanoreceptors/ proprioceptors
metaboreceptors
thermoreceptors
nociceptors
baroreceptors
stretch receptors, sensitive to changes in blood pressure
chemoreceptors
chemical receptors, chemical environment of the blood
mechanoreceptors/ proprioceptors
muscle tension and length
metaboreceptors
skeletal muscle metabolites
thermoreceptors
temperature regulation
nociceptors
pain
interneurons
pain response example - a shortcut needed
pass afferent transmission to efferent response without need to involve brain
spinal cord can control simple motor reflexes
brain controls more complex and sometimes subconscious motor reactions
myotatic/ stretch reflex
stretch sensed by M-spindles
afferent signal to spinal cord
sensory neurons transmit signal
- motor neurons
- interneurons
motor neurons send efferent impulses to agonist muscle to contract
interneurons block motor neurons signalling antagonist muscle to not contract
efferent division - control
autonomic nervous system
involuntary processes
-SNS and PNS
somatic nervous system
motor neurons
- skeletal muscle function
sensory function
to sense change in the internal and external environment through sensory receptors
afferent functions
integrative function
to analyse the sensory information, store some aspects and make decisions
interneurons
motor function
to respond to stimuli by initiation of action
efferent neurons
neurones
functional unites of nervous system
convert stimuli to nerve impulses
neuroglia (microglia)
do not generate or conduct nerve impulses
protective and supporting
oligodendrocytes
support cells in CNS
astrocytes
regulate electrical transmission in brain
motor unit
two components
- alpha-motor neuron (AMN)
- muscle fibres innervated by the AMN
three types
- slow ( type 1 fibres)
- fatigue resistant (type IIa fibres)
- fast fatiguing ( type IIx fibres)
one motor neuron innervates each single muscle cell
anatomy of a neuron
dendrites (little trees)
- picking up signals
axon hillock
- nerve impulse generated
axon
- carries electrical impulse away from cell body
synapses
- contact point
myelinated neuron
Schwann cells
- myelin sheath: most nerve fibres are surrounded by an insulating, fatty sheath called a myelin sheath
nodes of Ranvier (periodic breaks of myelin sheath)
speed of transmission of the impulses