Unit 3, NERVOUS SYSTEM, (MODULE 11.3) BIOLOGY 106
What are Efferant Fibers?
Axons that carry instructions from the CNS to Peripheral tissues. **Somatic Effectors**
What are Afferant Fibers?
Axons that carry sensory information to the CNS>
Are unipolar neurons in a tissue sample of the PNS more likely to have a sensory or a motor function?
Because most sensory neurons of the PNS are Unipolar---These neurons are more likely have a sensory function. **Motor Neurons which are Multipolar have a motor function and are found in the CNS.
What are Somatic Motor Neurons?
The cell body of a Somatic Motor Neuron lies in the CNS and its axon extends within a Peripheral nerve to innervate skeletal muscle fibers at neuromuscular junctions. **Innervate Skeletal Muscles** *Conscious control over the activity of neurons*
What is Bipolar Neuron?
They are small and rare and occur in special sense organs where they relay information about sight, smell, hearing from receptor cells to other neurons.
What do Somatic Sensory Neurons do?
They monitor the outside world and our position within it.
What is an Interneuron?
They receive sensory information from the PNS as well as input from other Interneurons in the CNS. **Also responsible for higher functions such as: Memory, Planning, and Learning.**
Where are Interneurons located?
They usually lie between sensory neurons and motor neurons. **CNS**
What are proprioceptors?
UNCONSCIOUS information received. Detect BODY POSITION in space and movement. Located in the muscles, tendons, and joints inside the body and semicircular canals of the inner ear
What are Sensory Neurons?
Unipolar Neurons whose cell bodies are located in Sensory Ganglia in the PNS. **Sensory Neurons form the Afferent division of the PNS---They also deliver information from sensory receptors to the CNS.
What are Visceral Motor Neurons?
Visceral Motor Neurons in the CNS control a 2nd set of visceral motor neurons and are locacted in the PNS. *Innervate all Peripheral effectors other than skeletal muscles that are Smooth, glands, cardiac muscle and adipose tissue throughout the body.
What is a Ganglion?
collection of neuron cell bodies in the PNS
What are the 2 distinct processes of Bipolar Neurons?
1) One dendritic process that branches extensively at its distal tip. 2) One axon with the cell body between the two.
What are the two divisions of the autonomic nervous system?
1) Parasympathetic Division 2) Sympathetic Division
What are the two types of Ganglia in the PNS?
1) Sensory Ganglia- cell bodies of sensory neurons. 2) Autonomic Ganglia- cell bodies of efferent neurons from the autonomic nervous system.
What are the 4 structural classifications of Neurons?
1. Anaxonic Neuron 2. Unipolar Neuron 3. Bipolar Neuron 4. Multipolar Neuron
What is a Multipolar Neuron?
2 or more dendrites and a single axon. They can be as long as Unipolar Neurons. **They are the longest and carry motor commands from spinal cord to small muscles that move the toes.** **All Motor Neurons that control Skeletal Muscles are Multipolar Neurons.** **Most common neurons in CNS**
What is a nerve?
A nerve is a bundle of axons in the PNS.
What is Parasympathetic Division?
Conserves energy as it slows the heart rate and increases intestinal and gland activity and relaxes sphincter muscles in the gastrointestinal tract. **The visceral effectors of this division is:** 1)Smooth Muscles 2)Glands 3)Cardiac Muscles
What is a Unipolar Neuron?
Dendrites and axon are continuous basically fused and the cell body lies off to one side. In this neuron the Initial Segment is the 1st portion of the axon and lies where dendrites converge. ***The rest of the process, which carries ACTION POTENTIALS is usually considered to be an Axon.
What are sensory receptors?
Either cells monitored by sensory neurons or processes of specialized sensory neurons.
What is an Anaxonic Neuron?
It is small and lacks anatomical features that distinguish dendrites from axons and all the cell processes look alike. They are located in the brain and in special sense organs and there functions are poorly understood.
What are Autonomic Ganglia?
It is the 2nd set of visceral motor neurons that innervates the peripheral effectors. **These neuron cell bodies are found in peripheral autonomic ganglia**
What type of neurons are linked to the Unipolar Neuron?
Most Sensory Neurons of the PNS are Unipolar. They may extend a meter or more ending at synapses in CNS and they are the longest carrying sensations from tip of toes to spinal cord.
How do you classify neurons based on their function?
Neurons are functionally classified as: 1) Sensory Neurons 2) Interneurons 3) Motor Neurons
How do you classify neurons based on their structure?
Neurons are structurally classified as: 1) Anaxonic 2) Bipolar 3) Unipolar 4) Multipolar
What is Sympathetic Divison?
Primary process is to stimulate the bodys fight-flight-or freeze response. **The visceral effectors of this division:** 1)Smooth Muscles 2)Glands 3)Cardiac Muscles 4)Adipose Tissue
What are interoceptors?
Receive sensory information from inside the body. Detect internal body sensation. Examples: from the viscera (hollow organs), stomach pain, pinched spinal nerves, and deep skin inflammation
What are exteroceptors?
Receive sensory information from outside of the body. Examples: Visual, auditory, tactile, gustatory, and olfactory **More complex senses are: Sense of taste, smell, sight, equilibrium, hearing.**
What are Sensory Ganglia?
Sensory Ganglia are neurons and glial cells that transmit sensory information from the periphery to the CNS.
What do Visceral Sensory Neurons do?
monitor internal conditions and the status of other organ systems.