Chapter 11: The Nervous System Flashcards
peripheral nervous system (PNS)
consists of nerves that connect CNS to other parts of the body; includes cranial and spinal nerves
cranial nerves
arising from brain
spinal nerves
arising from spinal cord
the PNS is also divided into..
autonomic & somatic
autonomic
cranial & spinal nerves that connect CNS to viscera (subconscious activity)
somatic
cranial & spinal nerves that connect CNS to skin & skeletal muscles (conscious activity)
sympathetic
ANS; fight or flight
parasympathetic
ANS; rest & digest, feed & breed
nerves
bundles of axons
connective tissue coverings (3)
- endoneurium
- perineurium
- epineurium
endoneurium
covers single axon
perineurium
covers group of axons
epineurium
covers whole nerve
sensory nerves
conduct impulses to brain or spinal cord
motor nerves
conduct impulses to muscles or glands
mixed nerves
sensory & motor, most mixed, all spinal nerves are mixed (except first pair)
general somatic efferent
carry motor impulses from CNS to skeletal muscles
general visceral efferent
carry motor impulses from CNS to smooth muscles & glands
general somatic afferent
carry sensory impulses to CNS from skin & skeletal muscles
general visceral afferent
carry sensory impulses to CNS from blood vessels & internal organs
sensory
afferent
motor
efferent
special somatic efferent
carry motor impulses from brain to muscle used in chewing, swallowing, speaking, & facial expressions
special visceral afferent
carry sensory impulses to brain from olfactory & taste receptors
special somatic afferent
carry sensory impulses to brain from receptors of sight, hearing, & equilibrium
2 types of autonomic neurotransmitters
cholinergic neurons & adrenergic neurons
cholinergic neurons
- release Ach
- all preganglionic sympathetic & parasympathetic fibers
- post ganglionic parasympathetic fibers
adrenergic neurons
- release norepinephrine
- most postganglionic sympathetic fibers
autonomic neurotransmitter action
result from binding to protein receptors in the membrane of effector cells in synapses or neuromuscular junctions
cholinergic receptors
- bind to Ach, two types
two types of cholinergic receptors
- muscarinic
- nicotinic
muscarinic
excitatory, slow, activated by fungal toxin
nicotinic
excitatory, rapid, activated by tobacco toxin
adrenergic receptors
- bind to epinephrine & norepinephrine; two types
two types of adrenergic receptors
- alpha
- beta
- both have different responses on various effectors
what occurs after acting at synapse or neuromuscular junction?
neurotransmitters must be removed/inactivated, to prevent continued stimulation of the postsynaptic cell
AchE
decomposes the acetylcholine that cholinergic fibers release
norepinephrine
from adrenergic fibers; removed from synapse by active transport, and inactivated by monoamine oxidase (MAO)
control of autonomic activity
- controlled largely by hypothalamus
- control of ANS is involuntary
- medulla oblongata regulates cardiac, vasomotor, and respiratory activity
- hypothalamus regulates homeostasis
- autonomic reflex centers occur in medulla oblongata & spinal cord
- reflex centers in medulla oblongata control cardiac, vasomotor, & respiratory activity
- limbic system & cerebral cortex control emotional responses