BIOLOGY 1002 - CHAPTER 39

What do association neurons do?

"Decide" what to do -Integration

What are the elements of a nervous system?

1. Sensory neurons 2. Association neurons 3. Motor neurons 4. Effectors

What are the similarities between hormonal communication and nervous cell communication?

Both types of communication make "messenger" chemicals that are released into extracellualr spaces

The more frequently an action potential is triggered by a stimulus, the greater the intensity of the sensation.

TRUE

The brain is able to take sensory inputs from many neurons, integrate them, and determine an appropriate response

TRUE

What does the insulin layer allow?

-Allows nerve impulses to travel more rapidly

What is the axon & what does it carry?

-Axon is a long thin fiber extending from the cell body -Axon carries the action potentials to output terminals. -Axons are bundled together into nerves CONDUCT & CARRY

What is a cell body & what does it do?

-Cell body receives various signals from the dendrites and produces an action potential (output signal) -The cell body coordinates metabolic activity of the cell *day to day things

Nerve cell (neuron) structure and function:

-Receive information: within/without body -Integrate the information: create appropriate response -Conduct the signal to its output terminal: travel down length of the neuron -Transmit the signal to other cells: other nerve cells, other types of cells -Coordinate their metabolic activities: make proteins, repare damage

What is a synaptic terminal & what is it the site of?

-Synaptic terminals are the sites at which signals are transmitted to other cells (glands, muscles, or dendrites of another neuron) -Transmission of the signal to the next cell occurs at the synapse and usually involves a group of chemicals called neurotransmitters

What are most axons wrapped in?

-Wrapped in insulating layers of membrane called myelin interrupted at intervals with naked areas called nodes

What are the four distinct parts of the neuron?

1. Dendrite 2. Cell body 3. Axon 4. Synaptic terminals

What are the four tasks of the nervous system?

1. Determine the type of stimulus (sensory neuron) 2. Signal the intensity of a stimulus (sensory neurons & interneurons) 3. Integrate the information from many sources (interneurons) 4. Initiate and direct the response to the many body parts (interneurons, motor neurons, & effectors)

Electrical signals are transmitted to the synaptic terminals along the:

Axon

Select the path an electrical signal would take within a single neuron

Dendrite -> Cell body -> Axon -> Synaptic terminal

Which part of the neuron receives signals from other neurons?

Dendrites -Dendrite send signals to the cell body in response to specific stimuli

How is the dertermination of the type of stimulus achieved?

Determination of the type of stimulus (light, touch, sound, etc.) is achieved by the nervous system monitoring which neurons are firing (ex. optic berve stimulation indicates light)

Hormone communication vs nervous cell communication

Distance: -Hormone - contacting cells far away -Nervous - close by, much shorter distance Number of cells contacted: -Hormone - almost all cells, many -Nervous - Only a few are contacted Speed: -Hormone - "a while"; about 1 sec -Nervous - 1,000-10,000 times faster

Dendrites release neurotransmitters at synapses

FALSE

The intensity of a stimulus is indicated by the ____ of action potentials

Frequency

How does a nerve impulse travel?

From the dendrites to the cell body down the axon, where an action potential is created, to the synaptic terminals, to dendrites of other neurons

What do sensory neurons do?

Respond to stimulus -They receive information

The site where a neuron communicates with another cell is called the ____.

Synapse -A synapse consists of the synaptic terminal of an axon and a receiving cell, such as a muscle cell, a gland cell, or the dendrite of another neuron

Your neurons transmit stimuli (sound, touch, order, etc) to your brain in the form of action potentials. How then does your brain distinguish between the various types of stimuli?

The brain determines the type of receptor and the region of the brain receiving the action potentials -For example, light receptors in the retina generate action potentials that travel through the optic nerve to the occipital lobes of the brain where the stimulus is interpreted as light

What is convergence?

The integration of the incoming information from many sources in the brain is achieved by convergence

What are effectors?

They preform the behaviors -Muscles or glands

What do motor neurons receive?

They receive instructions from association neurons and activate effectors -Message deliverers

What is a dendrite & what is its function?

-Dendrites are a tangle of fibers that branch from the cell body -Receive information from the environment and convert the information to electrical signals

What are the differeces between hormone communication and nervous cell communication?

-Distance -Number of cells contacted -Speed

What is the intensity of a stimulus?

-How many neurons & how rapidly? -Identified by the frequency of action potentials in a single neuron and the number of similar neurons firing at the same time

What is divergence?

Once integration is complete, the response of many body parts at once requires divergence

What is the primary function of a neuron?

Neurons receive, process, and transmit information -Neurons vary considerably in structure, but they all have the same basic function