Chapter 12 Flashcards
Which nervous system is composed of the brain and spinal cord?
The central nervous system (CNS) is composed of the brain and spinal cord.
Which system controls the skeletal muscles?
The somatic nervous system controls the skeletal muscles.
What are the differences between afferent, efferent, autonomic, and peripheral functions?
Afferent pathways carry sensory information to the CNS, while efferent pathways carry motor commands away from the CNS. The autonomic nervous system regulates involuntary functions, and the peripheral nervous system connects the CNS to limbs and organs.
How does motor information get to peripheral effectors?
Motor information travels through motor neurons from the CNS to peripheral effectors.
Which nerves connect to the spine vs brain?
Spinal nerves connect to the spine, while cranial nerves connect to the brain.
What comprises the axoplasm of the axon?
The axoplasm consists of cytoplasm within the axon, containing organelles and proteins.
What happens when the axoplasm is blocked?
Blocking the axoplasm disrupts the transport of materials along the axon.
What is the structural classification for neurons?
Neurons can be classified structurally as unipolar, bipolar, multipolar, or anaxonic.
What is the cytoplasm of a neuron called?
The cytoplasm of a neuron is called the perikaryon.
What are Nissl bodies?
Nissl bodies are rough endoplasmic reticulum and ribosomes found in the cell body of neurons.
How do axons connect to the soma?
Axons connect to the soma at the axon hillock.
What are axon branches called?
Axon branches are called axon collaterals.
How are axons terminated?
Axons terminate at synaptic terminals.
Where does intercellular communication between a neuron and another cell occur?
Intercellular communication occurs at synapses.
How does the rabies virus reach the CNS?
The rabies virus travels retrogradely along axons to reach the CNS.
What are the structural and functional variations between anaxonic, unipolar, bipolar, tripolar, and multipolar neurons?
Anaxonic neurons have no distinct axon, unipolar neurons have one process, bipolar neurons have two processes, tripolar neurons have three processes, and multipolar neurons have multiple processes.
What is the most numerous type of neuron in the CNS?
The most numerous type of neuron in the CNS is the multipolar neuron.
What are the functional variations of internoceptors, exteroceptors, and proprioceptors?
Internoceptors detect internal stimuli, exteroceptors detect external stimuli, and proprioceptors provide information about body position and movement.
What is the plasma membrane of an axon?
The plasma membrane of an axon is called the axolemma.
What is the functional unit of the nervous system?
The functional unit of the nervous system is the neuron.
What is the most common neuron of the nervous system?
The most common neuron in the nervous system is the multipolar neuron.
Do neurons undergo cell division? Why or why not?
Neurons generally do not undergo cell division due to their specialized function and structure.
What happens upon Wallerian degeneration?
Wallerian degeneration occurs when a nerve fiber is damaged, leading to degeneration of the axon distal to the injury.
What is the function and quantity of neuroglia?
Neuroglia support, protect, and maintain homeostasis for neurons; they outnumber neurons significantly.
What are the types of neuroglia?
Types of neuroglia include astrocytes, satellite cells, oligodendrocytes, microglia, and ependymal cells.
How is the myelin sheath formed?
The myelin sheath is formed by oligodendrocytes in the CNS and Schwann cells in the PNS.
How are the neurilemma of axons in the peripheral nervous system formed?
The neurilemma is formed by Schwann cells wrapping around the axon.
What happens upon damage to ependymal cells?
Damage to ependymal cells can disrupt the production and circulation of cerebrospinal fluid.
What happens when pressure is applied to neural tissue?
Applying pressure to neural tissue can disrupt blood flow and neuronal function.
How do Schwann cells participate in the repair of damaged nerves?
Schwann cells help repair damaged nerves by forming a regeneration tube.
What is the space between Schwann cells called?
The space between Schwann cells is called the internodal region.
What is the difference between gray and white matter composition?
Gray matter contains neuronal cell bodies, while white matter contains myelinated axons.
What are the causes of demyelination?
Demyelination can be caused by autoimmune diseases, infections, and genetic disorders.
What happens during the establishment of a neuron’s resting membrane potential?
During resting membrane potential establishment, sodium ions are pumped out and potassium ions are pumped in, typically in a 3:2 ratio.
What are active, gated, and leak channels?
Active channels require energy to transport ions, gated channels open in response to stimuli, and leak channels allow ions to pass freely.
What are the effects of open sodium channels in the axon membrane?
Open sodium channels lead to depolarization of the neuron.
Where are voltage-gated channels found?
Voltage-gated channels are found along the axon membrane.
What is the function of the sodium-potassium ion exchange pump?
The sodium-potassium pump maintains the resting membrane potential by moving sodium out and potassium into the cell.
What are chemically gated, voltage-gated, and mechanically gated channels?
Chemically gated channels open in response to neurotransmitters, voltage-gated channels open in response to changes in membrane potential, and mechanically gated channels open in response to physical deformation.
What happens when chemically gated, voltage-gated, or mechanically gated channels are blocked?
Blocking these channels prevents the normal flow of ions, disrupting neuronal signaling.
What contributes to creating the resting membrane potential of a neuron?
The resting membrane potential is created by the distribution of ions, particularly sodium and potassium, across the membrane.
What are the effects of sodium-potassium pumps in the plasma membrane functional failure?
Failure of sodium-potassium pumps can lead to depolarization and loss of resting potential.
What are graded potentials?
Graded potentials are changes in membrane potential that vary in size and can lead to action potentials.
How do ions move across the plasma membrane?
Ions move across the plasma membrane through channels and pumps.
What is the difference between activation gate and inactivation gate?
The activation gate opens in response to depolarization, while the inactivation gate closes to stop ion flow.
If acetylcholine (ACh) causes inhibition of a postsynaptic neuron, to what type of membrane channel did the ACh bind?
ACh binds to chemically gated channels to cause inhibition.
What is the difference between current, action potential, and electrochemical gradient?
Current refers to the flow of electric charge, action potential is a rapid change in membrane potential, and electrochemical gradient is the difference in ion concentration across a membrane.
What are the effects of depolarization, hyperpolarization, polarization, and repolarization on neurons?
Depolarization makes the inside of the neuron more positive, hyperpolarization makes it more negative, polarization refers to the resting state, and repolarization returns the membrane potential to resting state.
What is the equilibrium potential of potassium vs sodium?
The equilibrium potential for potassium is typically around -90 mV, while for sodium it is around +60 mV.
What is the all-or-none principle?
The all-or-none principle states that an action potential occurs fully or not at all.
How would the absolute refractory period be affected if voltage-regulated sodium channels failed to inactivate?
If sodium channels failed to inactivate, the absolute refractory period would be prolonged, preventing subsequent action potentials.
How would a chemical that prevents the opening of voltage-regulated Na+ channels affect the function of a neuron?
It would prevent depolarization and inhibit action potential generation.
What is a threshold stimulus?
A threshold stimulus is the minimum level of stimulus required to trigger an action potential.
What are the differences between spatial, saltatory, and divergent continuous propagation?
Spatial propagation involves multiple neurons, saltatory propagation occurs along myelinated axons, and divergent propagation spreads signals to multiple targets.
What conditions influence the time necessary for a nerve impulse to be transmitted?
Factors include axon diameter, myelination, and temperature.
What are the structures and functions of type A, B, C, D, and E nerve fibers?
Type A fibers are large and myelinated for fast conduction; type B fibers are medium and myelinated; type C fibers are small and unmyelinated for slow conduction.
What conditions affect the rate of impulse conduction?
The rate of impulse conduction is affected by myelination, axon diameter, and temperature.
What are relative refractory, absolute refractory, resting, lag, and stationary periods?
Relative refractory period is when a stronger stimulus can initiate an action potential; absolute refractory period is when no stimulus can initiate one; resting is the stable state; lag is the time after an action potential; stationary is when the membrane potential is stable.
How does myelin affect action potential?
Myelin increases the speed of action potential propagation through saltatory conduction.
What are the effects of neurotransmitters on presynaptic vs postsynaptic neurons?
Neurotransmitters can excite or inhibit postsynaptic neurons, while presynaptic neurons release them.
Which type of synapse is most common in the nervous system?
Chemical synapses are the most common type in the nervous system.
Which ion triggers the release of acetylcholine into the synaptic cleft?
Calcium ions trigger the release of acetylcholine.
