introduction to the CNS Flashcards
what is the CNS
the center of all mental activity (thought, learning, memory)
____________ and _____________ are responsible for regulating and maintaining homeostasis
CNS; endocrine system
CNS components
- the brain
- spinal cord
- nerves
- ganglia
sensory receptors
detect internal or external stimuli and relay information to the CNS
integration
analysis, storage, decision making, perception
motor
- muscular contraction
- glandular secretion
CNS v PNS
- CNS: brain and spinal cord
- PNS: nerves and ganglia
brain lobes
- frontal
- temporal
- parietal
- occipital
- insular
frontal lobe
- decision making
- control of voluntary movement
what part of the brain contains Broca’s area
left side of the frontal lobe
parietal lobe
processing sensory and spatial information
temporal lobe
processing memories and integrating them with emotion and taste, sight, touch, sound
what part of the brain contains Wernicke’s area
left side of the temporal lobe
occipital lobe
vision
does the spinal cord extend the entire length of the vertebral column
no
how long is the spinal cord in men and women
- men: 45 cm (18 in)
- women: 43 cm (17 in)
spinal cord width in the cervical region
1/2 inch
spinal cord width in the lumbar region
1/2 inch
spinal cord width in the thoracic region
1/4 inch
how many segments in the spinal cord
30
spinal cord functions
- conduit of motor information that travels down the spinal cord
- conduit of sensory information in the reverse direction
- center for coordinating certain reflexes
embryonic and evolutionary development of the CNS
nerve cell parts
- cell body
- dendrites
- axon
- axon terminals
nerve cell body
- receptive region
- biosynthesis
nerve cell dendrites
- single or multiple
- receptive region
nerve cell axon
- one per nerve cell
- collaterals
- sometimes covered in myelin sheath
- nodes of ranvier
which nerve cells have myelin sheaths
- schwann cells
- oligodendrocytes
nerve cell axon terminals
- synaptic end bulbs
- neurotransmitters
white matter v gray matter
neuroglia of the CNS (support cells)
- astrocytes
- oligodendrocytes
- microglia
- ependymal cells
neuroglia : nerve cell ratio
10:1
astrocytes
- physical support
- blood-brain barrier
- regulation of neurogenesis and synaptogenesis
- regulation of chemical environment
microglia
phagocytes
ependymal cells
produce CSF
how do neurons communicate
- action potential
- neurotransmitter release
- neurotransmitters
action potential
- resting potential in neurons is -70 mV
- depolarization occurs after action potential is fired
- depolarization spreads in one direction
what happens when the action potential reaches axon terminals
- action potential reaches the presynaptic axon terminal (neuron 1)
- action potential stimulates chemical neurotransmitter from synaptic vesicles
- neurotransmitter cross synaptic cleft and reaches postsynaptic neuron (neuron 2)
- neurotransmitter binds a receptor
- receptor is activated and transmits a signal inside the postsynaptic neuron
a chemical synapse is either …. or …
excitatory; inhibitory
excitatory
- triggers influx of Na+ ions
- triggers a nerve impulse in the second neuron
inhibitory
- increases membrane permeability to K+ or Cl- ions
- inhibits action potential in the second neuron
agonists
stimulate the receptor
antagonists
inhibit the receptor by blocking the neurotransmitter action
action of neurotransmitters is carefully regulated by __________, _________, or _______________
diffusion; reuptake; degradation
neuromuscular junction
- specialized synapse between a motor neuron and a muscle fiber
- occurs mid-length of muscle fiber
neuromuscular junction neurotransmitter
acetylcholine
where is the acetylcholine receptor in a neuromuscular junction
motor end of the muscle fiber
what does the binding of acetylcholine to its receptor trigger
influx of Na+ ions and generation of a muscle action potential
