Flashcards in List #7 Deck (46)
-lipid material that forms a sheath like covering around some axons
- movement occurs in both directions between the cell body and the ends of the axon.
-enzymes required for neurotransmitter synthesis are produced in the cell body and transported to the axon terminals.
- The potential difference across the cell membrane(measured in millivolts)
resting membrane potential
- one that is not sending impulses or responding to other neurons(-70 millivolts)
- a rapid change in the membrane potential, first in a positive direction, then in a negative direction, returning to the resting potential
- all or nothing
- if the membrane becomes more positive than the resting potential
-can be caused by Sodium entering
- means the threshold is lowered for an action potential
- if the membrane potential becomes more negative than the resting potential
-the threshold is raised
- During the absolute refractory period which lasts about 1/1,000 of a second, the axon's voltage-gated sodium channels are temporarily not responsive at all, and the axon cannot be stimulated.
-Then the relative refractory period follows, as the membrane reestablishes its resting potential.
-Action potentials appear to jump form node to node
- conduction on myelinated axons is many times faster than conduction on unmyelinated axons
- enable one neuron the affect another
- A neuro transmitter binds to a post-synaptic receptor and opens sodium ion channels, the ions diffuse inward, depolarizing the membrane possibly triggering an action potential.
- lasts for about 15 milliseconds
-A different neurotransmitter binds other receptors and increases membrane permeability to potassium ions, these ions diffuse outward hyperpolarizing the membrane
- modified amino acids
- These peptides act as neurotransmitters or a neuromodulators, which are substances that alter a neurons response to a neurotransmitter or block the release of a neurotransmitter.
-enkephalins and endorphins
-Generally inhibitory; reduce pain by inhibiting substance P release (CNS)
glutamic acid (glutamate)
-Generally excitatory (CNS)
- Inactivates the monoamine neurotransmitters epinephrine and norepinephrine after reuptake
- It is found in the mitochondria in the synaptic knob
-Primarily inhibitory; leads to sleepiness; action is blocked by LSD, enhanced by selective serotonin reuptake inhibitor antidepressant drugs (CNS)
- Neurotransmitter affected: Serotonin
-Mechanism of Action: Stimulates neurotransmitter synthesis
- Creates a sense of well-being; deficiency in some brain areas associated with Parkinson disease (CNS)
- Generally inhibitory (CNS)
-Any group of neuropeptides synthesized in the pituitary gland and hypothalamus that suppress pain
-located between the bone and the soft tissues of the nervous system
-They have three layers the dura mater, arachnoid mater, and the pia mater
-Nerves that arise from the spinal cord
- Components of a reflex, consisting of a sensory receptor, sensory neuron, interneuron, motor neuron, and effector
patellar knee jerk reflex
- example of a simple monosynaptic reflex, so-called because it uses only two neurons- a sensory neuron communicating directly to a motor neuron.
ascending and descending tracts of the spinal cord
-ascending tracts of the spinal cord are afferent information dealing with sensory neurons
-descending tracts of the spinal cord deal with efferent information and motor neurons
central nervous system
-Consists of the brain and spinal cord.
peripheral nervous system
-Consists of cranial and spinal nerves