Studied by 10 people
Functions of Nervous System
1.) Sensory Input 2.) Integration 3.) Control of muscles and glands 4.) Homeostasis 5.)Mental Activity
Central Nervous System
Brain and spinal cord.
Peripheral Nervous System
Sensory receptors and nerves
Sensory Division
(Afferent Division) Sends action potentials from sensory receptors to CNS.
Motor Division
(Efferent Division) Sends action potentials from CNS to muscles, organs, or glands.
Somatic Motor
Sends action potentials from CNS to skeletal muscles (voluntary).
Autonomic NS
Sends action potentials from CNS to cardiac muscle, smooth muscle, and glands (involuntary).
Sympathetic Division
Active during physical activity, "fight or flight" NS during emergencies.
Parasympathetic Division
Active during resting, regulates some digestion and other "vegetative" functions.
Enteric Division
Located in digestive tract, runs most of digestion independent of the CNS.
Neuron
(Nerve cells) Cells that actually receive and transmit action potentials.
Neuroglia
(Glial Cells) Cells that support the neurons. They do NOT transmit and receive APs, they have functions to help the neurons transmit and receive APs.
Yes
Can you label this picture?
Soma
Main cell body
Trigger Zone
Beginning of axon and place where a new action potential originates.
Dendrites
Extensions of the cell membrane which have dendrite spines.
Dendrite Spines
Allow axons from other cells to form synapses.
Axon
Long tail of cell, often called the nerve fiber.
Synapse
Any connection point between an axon and another cell.
Presynaptic Terminal
An ending of an axon at the synapse.
Bipolar
1 dendrite & 1 axon Found in retina of eye and in nasal cavity.
Unipolar
Has axon but the other end is not actually dendrites. Often has a receptor instead of the dendrite, most sensory neurons are like this.
Multipolar
Many dendrites and 1 axon. Most CNS and motor neurons are like this.
Types of CNS Glial Cells
1.) Astrocytes 2.) Ependymal Cells 3.) Microglial 4.) Oligodendrocytes
Types of PNS Glial Cells
1.) Schwann Cells 2.) Satellite Cells
Astrocytes
Forms link between blood vessel & neuron, can dilate or contract nearby blood vessels, help form synapses, regulate amount of ions available (needed for APs), and produces lactic acid for "back up energy" when glucose is low for neurons.
Reactive Astrocytes
Production of many astrocytes after a CNS injury. They wall of injury sites and limits inflammation, and limits regeneration of the damaged axons.
Ependymal Cells
Line ventricles of brain and spinal cord, (with blood vessels) form choroid plexus.
Choroid Plexus
Produces cerebrospinal fluid.
Microglia
The CNS's version of white blood cells, breaks down dead cells and invading microoganisms.
Oligodendrocytes
Wrap around axons and form myelin sheaths, only in the CNS.
Schwann Cells
Form myelin sheaths of PNS.
Satellite Cells
Surround soma (cell body), also helps gen nutrients to cell and absorb poisons away from it.
Functions of Myelin
1.) Insulates the signal (prevents signal from jumping to nearby axons). 2.) Encourages faster action potential propagation.
surrounded
Myelinated and unmyelinated axons are different based on how they are ____________ by Schwann cells or oligodendrocytes.
Myelinated Axons
Schwann cells or oligodendrocytes wrap around axon.
Unmyelinated Axons
Axons are "buried" within Schwann cells or oligodendrocytes but are not individually wrapped.
Action Potential
The electrical signal of the body.
Ligand-gated ion channels
Opens only for a specific ligand (molecule).
Voltage-gated ion channels
Opens only when a specific membrane potential is reached.
Leak channels
Always open and slowly leak one type of ion.
Sodium-Potassium Pump
Uses energy (ATP) to force K+ inside the cell and force Na+ outside the cell.
Resting Membrane Potential
The membrane potential in a normal or unstimulated cell.
Membrane Potential
Difference in charges between the sides of the membrane.
Polarized
When one side of the membrane is + and the other is -, the membrane is said to be _________.
-70 mV
The resting membrane potential of neurons.
Items Affecting Membrane Potential
1.) Ions 2.) Depolarization 3.)Hyperpolarization
Ions Affecting Membrane Potential
Na+, K+, Ca+2, Cl-
Depolarization
Decrease in the membrane potential, charges difference is becoming closer to 0 mV.
Hyperpolarization
Increase in the membrane potential, charge difference is becoming further from 0 mV.
Graded Potential
Any change in the resting membrane potential, or any stimulus that can affect an ion pump or channel. Ex.) ligand binding to receptor, voltage change, mechanically opening a gate, temperature change, pH change
Summation
The adding up effect of multiple graded potentials.
proportional
Graded potential strength is ___________ to the stimulus.
Threshold
The level of voltage that must be reached for the change in membrane potential to spread to nearby parts of the cell membrane.
