Study Guide - Chapter 11 Flashcards
(17 cards)
What are the two main divisions of the nervous system?
Peripheral nervous system and central nervous system
The peripheral nervous system connects the central nervous system to limbs and organs, while the central nervous system consists of the brain and spinal cord.
What are the two divisions of the peripheral nervous system?
Somatic nervous system and autonomic nervous system
The somatic nervous system controls voluntary movements, while the autonomic nervous system regulates involuntary functions.
What are the two subdivisions of the autonomic nervous system?
Sympathetic division and parasympathetic division
The sympathetic division prepares the body for ‘fight or flight’ responses, while the parasympathetic division promotes ‘rest and digest’ activities.
What is the major role of the central nervous system?
Processing and integrating information
The central nervous system is responsible for interpreting sensory information and coordinating responses.
What is the major role of the peripheral nervous system?
Connecting the central nervous system to the rest of the body
It transmits signals between the brain/spinal cord and limbs/organs.
List the six types of neuroglia and their basic functions.
- Astrocytes: support and repair neurons
- Microglia: immune defense in the CNS
- Ependymal cells: produce cerebrospinal fluid
- Oligodendrocytes: myelinate CNS axons
- Schwann cells: myelinate PNS axons
- Satellite cells: support neuron cell bodies in PNS
These glial cells play various supportive roles in the nervous system.
What are the functional classifications of neurons?
Sensory neurons, motor neurons, and interneurons
Sensory neurons transmit signals to the CNS, motor neurons convey signals to muscles, and interneurons connect neurons within the CNS.
What factors establish the resting membrane potential?
Ion concentrations (K and Na), ion channels, and Na+/K+ pumps
The resting membrane potential is primarily influenced by the differential distribution of potassium and sodium ions across the membrane.
What is the concentration of K relative to Na in the membrane potential?
Higher concentration of K inside the cell compared to Na
This difference is crucial for maintaining the resting membrane potential.
What critical role does the Na/K pump play in muscle activity?
Maintains the resting membrane potential and ionic balance
The Na/K pump actively transports Na out of the cell and K into the cell, which is essential for muscle contraction.
Contrast a graded potential and an action potential.
Graded potential: variable strength, local changes; Action potential: all-or-none, uniform strength
Graded potentials can vary in magnitude, while action potentials are always the same size once they reach the threshold.
Distinguish EPSP vs IPSP.
EPSP: excitatory postsynaptic potential; IPSP: inhibitory postsynaptic potential
EPSPs depolarize the postsynaptic membrane, while IPSPs hyperpolarize it.
Where do EPSPs and IPSPs occur?
At the postsynaptic membrane of neurons
They are generated in response to neurotransmitter binding.
Is summation possible in graded potential and action potential?
Yes, summation is possible in graded potentials; No, it is not in action potentials
Graded potentials can add together, while action potentials occur as discrete events.
Describe key events at each phase of a nerve action potential.
- Depolarization: Na+ channels open, Na+ influx
- Repolarization: K+ channels open, K+ efflux
- Hyperpolarization: K+ channels remain open longer
These phases are critical for the propagation of the action potential along the axon.
What does ‘all-or-none’ mean in muscle contraction?
Muscle fibers contract fully or not at all
This principle ensures consistent force generation once the threshold is reached.
What is the difference in action potential propagation between myelinated and unmyelinated axons?
Myelinated axons: faster propagation via saltatory conduction; Unmyelinated axons: slower, continuous conduction
Myelination increases the speed of electrical signals due to insulation and nodes of Ranvier.
