Podcast
Questions and Answers
Which of the following statements about the absolute refractory period is true?
Which of the following statements about the absolute refractory period is true?
A new action potential can occur during the relative refractory period with a normal stimulus.
A new action potential can occur during the relative refractory period with a normal stimulus.
False
What neurotransmitter is key to initiating the long-term potentiation (LTP) process?
What neurotransmitter is key to initiating the long-term potentiation (LTP) process?
Glutamate
In the LTP mechanism, the influx of __________ through AMPA receptors causes depolarization.
In the LTP mechanism, the influx of __________ through AMPA receptors causes depolarization.
Signup and view all the answers
Match the following terms to their definitions:
Match the following terms to their definitions:
Signup and view all the answers
What occurs in the NMDA receptor during LTP when depolarization happens?
What occurs in the NMDA receptor during LTP when depolarization happens?
Signup and view all the answers
K⁺ channels remain open during the relative refractory period.
K⁺ channels remain open during the relative refractory period.
Signup and view all the answers
What role does calcium (Ca²⁺) play in the long-term potentiation mechanism?
What role does calcium (Ca²⁺) play in the long-term potentiation mechanism?
Signup and view all the answers
During LTP, increased __________ release enhances synaptic transmission.
During LTP, increased __________ release enhances synaptic transmission.
Signup and view all the answers
Which of the following is NOT a characteristic of the refractory periods?
Which of the following is NOT a characteristic of the refractory periods?
Signup and view all the answers
Which division of the peripheral nervous system is responsible for voluntary movements?
Which division of the peripheral nervous system is responsible for voluntary movements?
Signup and view all the answers
Microglia are responsible for myelinating axons in the central nervous system.
Microglia are responsible for myelinating axons in the central nervous system.
Signup and view all the answers
What is the function of astrocytes in the central nervous system?
What is the function of astrocytes in the central nervous system?
Signup and view all the answers
The __________ Division of the autonomic nervous system is known for its 'rest and digest' response.
The __________ Division of the autonomic nervous system is known for its 'rest and digest' response.
Signup and view all the answers
Match the following glial cells with their primary function:
Match the following glial cells with their primary function:
Signup and view all the answers
What is the primary role of the sympathetic division of the autonomic nervous system?
What is the primary role of the sympathetic division of the autonomic nervous system?
Signup and view all the answers
Graded potentials are all-or-nothing responses, whereas action potentials vary in strength.
Graded potentials are all-or-nothing responses, whereas action potentials vary in strength.
Signup and view all the answers
What changes occur in ion permeability during an action potential?
What changes occur in ion permeability during an action potential?
Signup and view all the answers
The relative refractory period occurs __________ an action potential when a neuron is less likely to fire another action potential.
The relative refractory period occurs __________ an action potential when a neuron is less likely to fire another action potential.
Signup and view all the answers
Which of the following best describes the function of the enteric nervous system?
Which of the following best describes the function of the enteric nervous system?
Signup and view all the answers
Study Notes
Nervous System Organization
- The central nervous system (CNS) is comprised of the brain and spinal cord, processing and coordinating information.
- The peripheral nervous system (PNS) carries signals to and from the CNS.
- The afferent division of the PNS carries sensory input from receptors to the CNS.
- The efferent division of the PNS carries motor output from the CNS to effectors.
- The somatic nervous system (SNS) controls voluntary movements of skeletal muscles.
- The autonomic nervous system (ANS) controls involuntary functions like smooth muscle, cardiac muscle and glands.
- The sympathetic division is responsible for "fight-or-flight" responses.
- The parasympathetic division is responsible for "rest-and-digest" responses.
- The enteric nervous system (ENS) is a network of neurons in the gastrointestinal tract.
Glial Cells
- In the CNS:
- Astrocytes maintain the blood-brain barrier, support structure, and regulate ion and neurotransmitter concentrations.
- Oligodendrocytes myelinate CNS axons, increasing signal transmission speed.
- Microglia act as immune cells, removing debris and pathogens.
- Ependymal cells are a source of neural stem cells.
- In the PNS:
- Schwann cells myelinate PNS axons, aiding in repair after injury.
- Satellite cells surround neuronal cell bodies in ganglia, providing support and nutrient exchange.
Graded and Action Potentials
- Graded potentials are input signals that occur in dendrites and cell bodies, initiated by stimuli and can be summed.
- They are usually depolarizing or hyperpolarizing.
- Action potentials are regenerating conduction signals that travel through the axon, triggered by above-threshold graded potentials.
- They are all-or-none phenomena.
Action Potential Changes
- Resting phase: Resting membrane potential (approximately -70 mV) is maintained by the Na+/K+ pump and leak channels.
- Depolarization: Voltage-gated Na+ channels open, causing Na+ influx and a more positive membrane potential.
- Repolarization: Voltage-gated Na+ channels close, and voltage-gated K+ channels open, leading to K+ efflux and a return to resting potential.
- Hyperpolarization: K+ channels close slowly, resulting in an overshoot below resting potential before stabilizing.
Refractory Periods
- Absolute refractory period: No new action potential can be triggered due to inactivated Na+ channels.
- Relative refractory period: A stronger-than-normal stimulus can trigger a new action potential, as some Na+ channels are returning to their resting state, and K+ channels remain open.
Synaptic Communication
- Ionotropic receptors are ligand-gated ion channels mediating fast synaptic transmission. (e.g., AMPA receptors)
- Metabotropic receptors are G-protein-coupled receptors mediating slower, longer-lasting effects.
- Neurotransmitters are chemical messengers.
- Neuromodulators affect neurotransmitter release or receptor sensitivity.
- Fast synaptic potentials are brief changes in membrane potential due to ion flow.
- Excitatory postsynaptic potentials (EPSPs) depolarize the membrane.
- Inhibitory postsynaptic potentials (IPSPs) hyperpolarize the membrane.
- Slow synaptic potentials are longer-lasting changes mediated by second messengers.
Long-Term Potentiation (LTP)
- LTP is a strengthening of synaptic transmission through mechanisms involving AMPA and NMDA receptors.
- Initial signal involves glutamate binding to both AMPA and NMDA receptors.
- AMPA activation triggers Na+ influx, causing depolarization.
- NMDA activation, following depolarization, removes Mg2+ block and allows Ca2+ influx, leading to intracellular signaling and enhanced glutamate release.
- Result: Enhanced synaptic transmission, related to learning and memory.
Studying That Suits You
Use AI to generate personalized quizzes and flashcards to suit your learning preferences.
Related Documents
Description
Test your knowledge on the organization of the nervous system, including the structures and functions of the central and peripheral nervous systems, afferent and efferent divisions, and various nervous systems. This quiz also covers the roles of glial cells in the CNS. Challenge yourself and learn more about how our bodies process information!
