Chapter 12 Flashcards
(23 cards)
What are the two major divisions of the nervous system?
CNS and PNS
What are the two types of cells found in the nervous system?
Neurons and glial cells
Define nucleus, ganglion, tract, and nerve.
Nucleus – localized cell bodies in CNS
Ganglion – localized cell bodies in PNS
Tract – bundle of axons in CNS
Nerve – bundle of axons in PNS
The enteric nervous system is part of which division of the nervous system and is it under somatic or autonomic control?
PNS and under autonomic control
List and define all parts of the neuron.
Cell body (soma) – contains nucleus and organelles
Dendrites – receive information at synapses
Axons – carry neural signal to synapse
Axon hillock – tapering of cell body to axon where neural signal initiates
Nodes of Ranvier – gaps in myelin covering along length of axon to speed up propagation
Axon terminal – at end of axon that makes connections with target cell at synapse
Where are unipolar, bipolar, and multipolar neurons found?
Unipolar – not found in vertebrates
Bipolar – olfactory epithelium and retina
Multipolar – all other neurons
List the 6 types of glial cells, where they are found, and functions of each.
Astrocyte – CNS – support
Microglia – CNS – immune surveillance and phagocytosis
Oligodendrocyte – CNS – produce myelin covering
Ependymal cell – CNS – create CSF and part of BBB
Satellite cell – PNS - support
Schwann cell – PNS – produce myelin covering
Which part of the nervous system does multiple sclerosis and Guillain-Barre affect?
Multiple sclerosis – CNS
Guillain-Barre – PNS
Demyelination diseases
What part of the neuron is where the action potential originates?
Axon hillock
What is the relay center of the brain that receives incoming sensory information and sends it to the cerebral cortex for integration and processing?
Thalamus
List the different types of gated channels and how they operate.
Ligand-gated – opens when signaling molecule (ligand) binds to receptor on membrane
Mechanically gated – opens in response to physical distortion of membrane
Voltage-gated – respond to change in electrical potential of the membrane
Leakage channels – randomly open and close
What is the resting membrane potential, its value, and how is it restored?
When the neuron is at rest and ion channels are not open, at -70 mV, and restored by the Na+/K+ ATPase
What are the threshold value and value of maximum depolarization?
-55 mV and +30 mV
What happens to the action potential when a stronger stimulus is applied?
Increased frequency of action potentials
What are the activation and inactivation gates in the voltage-gated sodium channels and their purpose?
Activation gate – opens when membrane passes -55 mV (threshold)
Inactivation gate – closes after specific period of time
What is the difference between relative and absolute refractory periods?
Absolute refractory period cannot generate another action potential no matter how strong the stimulus is due to the presence of the inactivation gate of the voltage-gated sodium channels
Relative refractory period can regenerate another action potential but requires a larger stimulus
What kind of propagation does unmyelinated axons undergo, and myelinated axons? How does the axon diameter affect the rate of conduction?
Unmyelinated – continuous conduction
Myelinated – salutatory conduction
Larger the diameter – faster the rate of conduction
What are IPSPs and EPSPs and where do they summate in the neuron?
IPSPs – hyperpolarizing graded potentials
EPSPs – depolarizing graded potentials
Summate at axon hillock/initial segment
What are the characteristics of the synapse and how do they relate to the NMJ?
Presynaptic element – motor neuron axon terminal
Neurotransmitter – acetylcholine
Synaptic cleft – space between cells that NT diffuse
Receptor proteins – nicotinic ACh receptors
Postsynaptic element – sarcolemma of muscle cell
NT elimination/re-uptake – eliminated by acetylcholinesterases
List the different neurotransmitter systems, their neurotransmitter, receptor, whether it is excitatory or inhibitory.
Cholinergic – acetylcholine – nicotinic and muscarinic – excitatory
Amino acid NT group – glutamate, GABA, glycine – glutamatergic, GABAergic, glycinergic – glutamate excitatory; GABA and glycine inhibitory
Biogenic amine group – dopamine, norepinephrine, epinephrine – dopaminergic (D1 and D2), adrenergic – D1 excitatory, D2 inhibitory, norepi and epi excitatory
Neuropeptides – met-enkephalin, beta-endorphin - unspecified
List the two types of receptors and how they function.
Ionotropic – ligand-gated ion channels
Metabotropic – G protein – 2nd messenger system
What are the two 2nd messengers and what makes them?
cAMP – made by adenylate cyclase
inositol triphosphate (IP3) – made by phospholipase C
What misfolded proteins are associated with AD and PD?
AD – beta-amyloid
PD – alpha-synuclein
