9.1-9.10
Neurons are more permeable to ____ ions than to ____ ions. ____ diffuses out of the cell mor easily.
-K+ -Na+ -K+
What are neurons composed of?
-cell body -dendrites -axons
In what two ways can neurotransmitters respond?
-excitatory -inhibitory
What are the four different types of neuroglia?
-microglial cells -oligodendrocytes -astrocytes -ependymal cells
What are the three major groups of neurons classified on their structure?
-multipolar neurons -bipolar neurons -unipolar neurons
What are the two types of nervous tissue?
-neurons -neuroglia
What are the two general functions of the nervous system?
-sensory function -motor function
What are the 3 groups of neurons classified based on their generalized function?
-sensory neurons -interneurons -motor neurons
What results from the diffusion of K+ out of the cell?
-slight + charge outside the cell -slight - charge inside the cell (~70mv)
What are the two categories of the peripheral nervous system?
-somatic nervous system -autonomic nervous system
Specialized masses of neurons located outside the brain or spinal cord (usually in wrists or feet, treatment= get something hard and smash it which pops it)
Ganglia
What are unipolar neurons composed of?
Ganglia
How many groups is the nervous system divided into?
2
To have a neuron conduct an impulse what needs to be reached?
A minimum signal
A short-lasting event in which the electrical membrane potential of a cell rapidly rises and falls.
Action potential
Once the threshold is reached the neuron will respond, there is no gradation to the response.
All or none response
Commonly found between neurons and blood vessels, regulate nutrients and ions in the tissue
Astrocytes
Protects the brain from many chemical fluctuations of the blood.
Astrocytes
What causes the capillaries to not be leaky?
Astrocytes
Controls involuntary effectors (examples: cardiac, digestion, breathing)
Autonomic nervous system
Send information away (only one, yet multiple connections)
Axon
Single dendrite and single axon (specialized regions such as the eyes, nose, and ears)- usually send signals in one direction
Bipolar neurons
Primary portion of the cell
Cell body
The system that includes the brain and the spinal cord
Central Nervous System
What is the cell surface of a neuron usually like?
Charged (polarized)
Similar to rough endoplasmic reticulum (protein synthesis)
Chloromatophilic substances
Receive impulses
Dendrites
Unequal distribution of + and - ions across the membrane
Distribution of ions
Responds to signals from the peripheral system (muscles, glands)
Effectors
Forms an epithelial-like layer covering brain parts, inner lining of the brain, and spaces in the spinal cord
Ependymal cells
Causing a reaction
Excitatory
Neurotransmitters that increase membrane permeability.
Excitatory
Information is transferred between neurons by electrochemical changes
Impulses
Inhibiting and reaction (stopping it)
Inhibitory
Neurotransmitters that decrease membrane permeability.
Inhibitory
Conduct impulses from one location in the brain to another
Interneurons
Found within the brain and spinal cord and are multipolar
Interneurons
What ions are located inside the membrane?
K+ (Potassium)
What does cytoplasm have that causes it to not be able to pass through the membrane?
Many negatively charged ions (PO4^-3 and SO4^-2)
Support neurons, phagocytize bacteria (swallow it), form scar tissue.
Microglial cells
Peripheral neurons conduct impulses from the CNS.
Motor function
Multipolar and conduct impulses out of the Central Nervous System to effectors
Motor neurons
Controls muscles and glands
Motor neurons and effectors
Multiple dendrites and a single axon (brain, spinal cord)
Multipolar neurons
Tightly rolled cell membranes with nucleus outside the myelin
Myelin sheath
What ions are located outside the membrane?
Na+ (Sodium)
What does it mean to say that the minimum signal needs to cross the threshold potential?
Na+ ions need to move inside the membrane
Section of the cell with the majority of the cytoplasm and nucleus
Neurilemma
Fine threads (keratin) extending into the axon, thought to regulate diameter, and add strength
Neurofibrils
Cells that support the neurons in the central nervous system.
Neuroglia
During development, they guide the differentiation of neurons (tells neurons where to grow).
Neuroglia
Provides support, insulation, and nutrition for neurons.
Neuroglia
They can divide (unlike neurons) and are more numerous (take care of all debris and infections).
Neuroglia
Primary functional units of the nervous system
Neurons
Chemical singes that cross the gap and binds to a receptor
Neurotransmitters
Gaps between adjacent Schwann cells
Nodes of Ranvier
What are groups of interneurons called?
Nuclei
Wrap around axons forming an electrical insulator (myelin) forming a myelin sheath
Oligodendrocytes
The system that includes the nerves that connect the body to the CNS.
Peripheral Nervous System
The difference between the inside and the outside charge of a nerve cell
Resting potential
Neuroglia producing myelin sheath around axons called what?
Schwann cells
Converts information into sensations, adding to memory, and producing thoughts.
Sensory function
Gathers information about the changes inside and outside the body.
Sensory function
It can detect oxygen levels, light, sound, and temperature.
Sensory function
It can integrate signals into pain, pressure, burning, or cold.
Sensory function
The body senses information with sensory receptors.
Sensory function
Conduct impulses from peripheral body parts to brain or spinal cord
Sensory neurons
Specialized receptor ends or connected to receptors on skin or organs
Sensory neurons
Controls skeletal muscles (example: running, jumping)
Somatic nervous system
Connection between axon and the postsynaptic neuron
Synapse
The synapse is not in direct contact but is separated by a small gap called what?
Synaptic cleft
The minimum signal needs to cross this threshold (~55mv)
Threshold potential
Long axon, small peripheral process is the dendrite (nucleus is set off to the side
Unipolar neurons
