Nervous System 1. Relays messages, processes info, analyzes data 2. Receives information from the environment from CNS to organs and glands 3. Transmits impulses from CNS to muscles and glands 4. Transmits impulses from sense organs to the CNS 5. Regulates voluntary activities 6. Regulates involuntary activities 7. controls organs at rest 8. controls organs in stress
Nervous System Central Nervous System Relays messages, processes info, analyzes data Peripheral Nervous System Receives information from the environment from CNS to organs and glands Motor Division Transmits impulses from CNS to muscles and glands Sensory Division Transmits impulses from sense organs to the CNS Somatic Regulates voluntary activities Autonomic Regulates involuntary activities Parasympathetic controls organs at rest Sympathetic controls organs in stress
The nervous system is composed predominantly of neural tissue, but also includes blood vessels and connective tissue. Neural tissue consists of two cell types: and
Neurons have processes that receive ( ) and processes that send ( ) impulses.
Biological messenger molecules ( ) convey these impulses across spaces ( ) between neurons and the cells they affect.
Neurons can be classified by structure and function. Structural Classification of Neurons 1. 2. 3. Functional Classification of Neurons 1. 2. 3.
A structural neuron in which the cell body has many processes, one of which is an axon and the rest dendrites Most common type of neuron in the brain and spinal cord
A structural neuron in which a process arises from each end of the cell body, one an axon and one a dendrite Located in specialized parts of the eyes, nose, and ears
A structural neuron in which a single process from the cell body divides into two branches and functions as an axon Located in ganglia
Functional neurons that conduct impulses from receptors in peripheral body parts into the brain or spinal cord Mostly unipolar neurons
Functional neurons that relay information between neurons in the brain and spinal cord Multipolar neurons
Functional neurons that conduct impulses from the brain or spinal cord out to muscles or glands Multipolar neurons
CNS Neuroglia 1. 2. 3. 4.
CNS star- shaped neuroglial cells between that transport substances between blood vessels and neurons
CNS neuroglial cell that forms myelin sheaths in the brain and spinal cord
CNS neuroglial cell that function in structural support and phagocytosis for immune protection
CNS neuroglial cell that forms a porous layer through which substances diffuse between the interstitial fluid of the brain and spinal cord and the cerebrospinal fluid
PNS Neuroglia 1. 2.
PNS neuroglial cell that forms myelin sheaths by wrapping tightly around the axons of peripheral neurons
PNS neuroglial cells that surround cell bodies of neurons in ganglia
There are two ion channels and one pump in the axon that help to conduct the action potential. ü ü ü
Voltage- gated Na + channels open when the membrane potential is at.
Voltage- gated K + channels open when the membrane potential is at.
When the membrane is at rest there are more negative charges inside the cell relative to outside the cell, resulting in a negative membrane potential of.
Describe the ion distribution that creates the resting membrane potential.
When a neuron receives a stimulus, positive charged ions flow into the cell body. The positive ions diffusing into the cell body cause the membrane potential to (depolarize, repolarize, or hyperpolarize).
As the neuron depolarizes, if the membrane potential reaches - 55 mv, what will happen?
Once the threshold has been reached, the voltage- gated Na + channels open and an action potential is conducted The Na + ions flow from a high concentration to a low concentration. Therefore, the Na + ions flow in which direction?
At +40 mv, Na + channels close and K + channel.
K + ions flow from a high concentration to a low concentration. Therefore, they flow in which direction?
K + ions flowing into the cell causes the membrane potential to (depolarize, repolarize, or hyperpolarize).
The cell actually repolarizes below the resting potential to - 90 mv, a process called (depolarization, repolarization, or hyperpolarization).
After hyperpolarization the voltage- gated K + channels.
With both voltage- gated ion channels closed, how does the neuron return to the - 70 mv resting membrane potential?
Does an impulse travel faster on a myelinated or unmyelinated axon?
Why does the impulse travel faster on a myelinated axon?
Neurons communicate with each other at.
The neuron conducting an impulse to the synapse is the sender, or neuron.
The neuron receiving input at the synapse is the neuron.
The process by which the impulse in the presynaptic neuron signals the postsynaptic cell is called.
Synaptic transmission is a one- way process carried out by chemical.
When an impulse reaches the axon terminal, what type of channels open?
Calcium diffuses from a high concentration to a low concentration. Therefore, calcium flows in which direction?
This influx of calcium ions into the presynaptic neuron, initiates the release of neurotransmitters by the process of.
Once the neurotransmitters are released into the synapse, they bind to receptors on the postsynaptic neuron. The effect of the neurotransmitter binding to the receptor could be excitatory or.
An excitatory potential could be produced through depolarization by the opening of what type of channels?
An inhibitory potential could be produced through hyperpolarization by the opening of what type of channels?