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88 Cards in this Set

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The three overlapping functions of the nervous system.
1. Gathering SENSORY INPUT.
2. Integrating the information, INTEGRATION.
3. Causing a response, MOTOR OUTPUT.
The Nervous system is divided into the ________ and the __________ systems.
Peripheral and Central systems.
The two divisions of the peripheral nervous system.
The sensory (afferent) and the motor (efferent) systems.
The sensory (afferent) system.
Consists of nerve fibers that carry impulses to the CNS. The input comes from sensory nerves in the skin and visceral organs.
The motor (efferent) system.
Consists of impulses coming from the CNS to the effector organs (muscles and glands).
The two divisions of the peripheral nervous system.
1. Motor (efferent)
2. Sensory (afferent)
Autonomic system.
Comprised of visceral nerve fibers that regulate activity of the smooth muscles, heart, and glands.
Somatic system.
Comprised of somatic nerve fibers (axons) that conduct impulses from the CNS to skeletal muscle.
This system is also called the voluntary system.
somatic nervous system is also called this.
The system is also called the involuntary system.
autonomic nervous system is also called this.
The autonomic nervous system is divided into these two divisions.
1. Sympathetic
2. Parasympathetic
The two major cell types present in the nervous system.
1. Neurons
2. Glial Cells
The excitable cell that transmits electrical impulses.
Neurons.
The supporting cells of the nervous system.
Glial cells.
The 6 types of glial cells found in the nervous sytem.
1. Astrocytes
2. Microglia
3. Ependymal cells
4. Oligodendrocytes
5. Satellite cells
6. Schwann cells
The glial cells founds in the CNS.
1. Oligodendrocytes
2. Ependymal cells
3. Microglia
4. Astrocytes
The glial cells found in the PNS.
1. Satellite cells
2. Schwann cells
These nervous system cells surround neuron bodies of the PNS.
Satellite cells.
The nervous system cells form myrlin sheaths around the larger nerve fibers.
Schwann cells.
These PNS cells are vital to regeneration and proper nerve signal transduction.
Schwann cells.
The ratio of glial to neuron cells.
_____ cells out number neurons 10:1 and make up half the brain's mass.
These are star shaped cells. Most abundant and versatile glial cell.
Astrocytes.
These cells control the chemical environment, mop up leaked k+ ions and recycle neurotransmitters.
Astrocytes.
These cells anchor neurons and their capillaries. They secrete chemicals that help young neurons make the right connections and help determine capillary permeability.
Astrocytes.
These cells are connected by gap junctions, communicate by calcium sparks, and influence neurons so that they help the info processing in the brain.
Astrocytes.
These are small, ovoid cells with thorny processes.
Microglia.
These cells monitor neuron health. They act like immune cells and macrophages in the brain. They can be migratory.
Microglia.
These cells range in shape from sqaumous to columnar and many are ciliated.
Ependymal cells.
These cells line the central cavity of the brain and spinal cord where they are a fairly permeable barrier between the cerebrospinal fluid and the cells of the CNS. Their cilia beating helps to circulate CSF.
Ependymal cells.
These are branching cells but have fewer processes than other cells. They produce myelin sheaths around thicker neurons of the CNS.
Oligodendrocytes.
Neurons.
These nerve cells have extreme longevity. Given good nutrition, these cells function a lifetime. They are amitotic and have a high metabolic rate.
amitotic.
Means cells do not divide.
Clusters of cell bodies in the CNS are called _________.
Nuclei.
Clusters of cell bodies along the nerves in the PNS are called _________.
Ganglia.
Bundles of neuron processes in the CNS are called _______.
Tracts.
Bundles of neuron processes in the PNS are called _______.
nerves.
The two types of neuron processes.
Dendrites and axons.
Dendrites.
The receptive region of neurons that gathers input.
Axon.
The part of neurons that carries information away.
Two ways of classifying neurons.
1. Structure (multipolar, bipolar, unipolar)
2. Function (sensory, motor)
Four gate types of membrane ion channels.
1. Voltage-gated.
2. Chemically (ligand) gated.
3. Mechanically gated.
4. Leakage (non-gated).
Voltage-gated membrane ion channel.
These channels open in response to changes in the membrane potential.
Chemically (ligand) gated membrane ion channel.
These channels open when a ligand binds to them.
Mechanically gated membrane ion channel.
These channels open physically deformed. (seen in sensory receptors for touch)
Leakage (non-gated) membrane ion channels.
These channels are always open.
The resting membrane potential for most cells is _____.
- 70 is the ___________ for most cells.
The cell is polarized when it is at it's ______________.
A cell is ___________ when it is at it's resting membrane potential (-70).
Two types of membrane potentials to send signals.
1. Graded potentials
2. Action potentials
Graded potentials.
Used for sending incoming messages over a short distance.
Action potentials.
Long distance signals used by axons.
Depolarization.
A reduction in membrane potential. The inside of the cell becomes less negative. (moves closer to zero)
Hyperpolarization.
When the inside of the cell becomes more negative. (makes the cell inhibitory to function)
Short-lived localized changes in the membrane potential that can either be depolarizing or hyperpolarizing. Essential to triggering action potentials.
Graded potentials.
The states of an action potentials.
1. Resting state.
2. Depolarizing phase.
3. Repolarizing phase.
4. Hyperpolarizing phase.
The relative refractory period occurs during the _________ phase.
The _____________ period occurs during the hyperpolarization phases.
Action potentials can occur in nerves only if ________________.
Another _________ can occur in nerves only if the started AP is completed and the cell has returned to it's resting potential.
The speed of transmission of an action potential signal.
The conduction velocity.
The conduction velocity is determined by the:
1. Axon diameter (larger=faster)
2. Myelination degree (no myelin sheath=slow conduction velocity)
Saltatory conduction.
In myelinated axons where AP are triggered at nodes and jump from node to node along the axon.
Multiple Sclerosis.
An autoimmune disease that causes demyelination. The destoryed myelin sheaths result in hardened leasions called 'scleroses.'
Symptoms of MS.
Causes blindness, muscle control problems including weakness and paralysis, speech problems, and urinary incontinence.
Treatment of MS.
Treated with Copaxone. helps with symptoms but doesn't stop the disease.
Three ways to classify nerve fibers.
1. Degree of myelination.
2. Diameter.
3. Conduction speed.
Group A Fibers.
Have the largest diameter, thick myelin sheaths, and the highest conduction velocity.
Group B Fibers.
Intermediate diameter, lightly myelinated fibers, transmit at 15 s/mm.
Group C Fibers.
The fibers with the smallest diameter, unmyelated, have the slowest conduction rate.
Group ___ Fibers are mostly somatic sensory and motor fibers serving skin, joints, and skeletal muscles.
Group A fibers are mostly ________________.
The junction between neurons or neurons and their effectors.
Synapse.
Synapses can be ___ or ____ and have a ______ side and _____ side.
electrical or chemical, have a postsynaptic and presynaptic side.
First event of depolarization at a chemical synapse.
Arrival of depolarization wave. Voltage-gated Ca2+ channels open to let Ca2+ enter axon terminal.
Second event of depolarization at a chemical synapse.
Synaptic vesicles fuse with the presynaptic membrane. Neurotransmitter is released into the synaptic cleft.
Third event of depolarization at a chemical synapse.
Neurotransmitter fuses across synaptic cleft and fuses to postsynaptic membrane.
Fourth event od depolarization at a chemical synapse.
Binding of neurotransmitter opens ion channels in postsynaptic membrane. This causes a graded potential.
Fifth event of depolarization at a chemical synapse.
Neurotransmitter is quickely destroyed by enzymes at synapse or taken back to presynaptic terminal. Depletion of neurtotransmitters close ion channels and terminate synaptic response.
EPSP's.
Excitatory postsynaptic potentials. Local graded depolarization response that helps to trigger action potentials.
IPSP's.
Inhibitory postsynaptic potentials. Inhibits the ability to produce action potentials by hyperpolarizing the cell locally. Graded response.
Direct response of neurotransmitters.
Response of neurotransmitters involving rapid and open ion channels.
Neurotransmitters can be _______ or ________ and can act through ________ or _______ mechanisms.
Excitatory or Inhibatory, Direct or indirect.
Indirect response of neorotransmitters.
Usually involve release of neuromodulators and G-protein signaling cascades. Slower responses.
Serial processing.
The whole system works in a predictable all or nothing response. (reflexes)
Reflexes.
Rapid and automatic responses to a particular stimuli.
Reflexes occur over neural pathways called _________.
Reflex arcs.
Important for higher functions where the stimuli is processed in the CNS and a response or series of responses are triggered.
Parallel Processing.
The two receptors for ACh.
1. Nicotinic ACh receptors. (on skeletal muscles, autonomic ganglia, and in CNS)
2. Muscarinic ACh receptors. (On visceral effectors and in the CNS)
Subthreshold, No Summation.
The EPSP graded response does not meet theshold and no AP is triggered.
Spatial Summation.
More then one EPSP graded respose and sent to the cell at the same time, an AP is triggered because the threshold is met.
Temporal Summation.
A EPSP graded respose is sent before the first EPSP graded response finished so the threshold is met and the AP is triggered.
Spatial summations of EPSP and IPSP.
When an IPSP and an EPSP are triggered at the same time, they cancel eachother out and nothing happens.