Unit I Review Flashcards
What are the anatomical components of the central nervous system?
Brain and spinal cord
What are the anatomical components of the peripheral nervous system?
All neural tissue outside of the CNS
What is the difference between spinal nerves and cranial nerves?
Point of origin
What type of information is carried by the afferent division of the PNS?
Sensory information
What type of information is carried by the efferent division of the PNS?
Motor commands
What is the difference between the somatic and autonomic nervous systems?
We have control over somatic system, which is skeletal muscle.
Most sensory neurons of the PNS are this type of neuron
Unipolar neuron
All motor neurons control skeletal muscle are this type of neuron
Multipolar neuron
Where are chemically gated sodium channels located on a neuron?
For the most part, the dendrites and cell body
What are the characteristics of Type A, Type B, and Type C fibers?
Type A - Largest myelinated axons, and fastest at approximately 268 mph
Type B - Smaller myelinated axons, traveling approximately 40 mph
Type C - Unmyelinated and slow, traveling only 2 mph
What are the main characteristics of excitatory and inhibitory neurotransmitters
Excitatory - Cause depolarization and promote action potentials
Inhibitory - Cause hyperpolarization and suppress action potentials
Explain the main events at a cholinergic synapse
- Action potential arrives at the presynaptic terminal
- Voltage-gated calcium channels open, and Ca2+ rushes in cause the release of ACh
- ACh diffuses across the synaptic cleft and binds to receptors on the postsynaptic terminal, causing chemically-gated Na+ channels to open resulting in a graded depolarization
- ACh is broken down into acetate and choline by AChE, and the choline is reabsorbed by the axon terminal to make more ACh.
What is the role of norepinephrine
Released at adrenergic synapses, has an excitatory effect. Found in portions of the ANS
What is the role of dopamine
May have inhibitory or excitatory effects. It inhibits muscle movements to prevent over-stimulation. Without dopamine Parkinson’s disease develops. In some areas of the brain, it causes excitatory effects.
What is serotonin
Affects attention and emotional states
What is GABA
Not fully understood. Generally inhibitory and used in some anti-anxiety medications.
What is nitric oxide
Generated by axon terminals that innervate smooth muscle in the walls of blood vessels.
What are neuromodulators
Alter the rate of release of neurotransmitters or change the postsynaptic response
What are the four classes of opioids and what are their primary functions?
- Endorphins
- Enkephalins
- Endomorphins
- Dynorphins
Primary use is to relieve pain by inhibiting release of substance P at pain synapses
What are postsynaptic potentials
Graded potentials that develop at the postsynaptic membrane
What is an EPSP
A graded depolarization caused by the arrival of a neurotransmitter at the postsynaptic membrane
What is an IPSP
A grade hyperpolarization of the postsynaptic terminal. For example, could result from the opening of chemically-gated K+ channels.
What is temporal summation?
Additional stimuli occurring in rapid succession at a single synapse
What is spatial summation?
Stimuli arrive simultaneously at different locations, causing a cumulative effect on the membrane potential.