Chapter 48 (1)

the nerve cells that transfer information within the body

Communication by neurons consists of two distinct types of signals: __ and __.

The specialized structure of __ allows them to use pulses of electrical current to receive, transmit, and regulate the flow of info over long distances within the body. In transferring info from one cell to another, __ often rely on chemical signals taht act over very short distances.

What types of info do neurons transmit?
- All of this info is transmitted within neurons as an __, consisting of the movement of ions. The connections made by a neuron specify what info is transmitted. Interpreting signals in the nervous system therefore involves sorting a complex set of neuronal paths and connections. In more complex animals, this higher-order processing is carried out largely in groups of neurons organized into a __ or into simpler clusters called __.

What are the three stages in information processing?

__ transmit info from eyes and other sensors that detect external stimuli (light, sound, heat, touch, smell, and taste) or internal conditions (BP, CO2, muscle tension).
This info is sent to processing centers in the __ or in __.

Neurons in the __ or __ integrate (analyze and interpret) the sensory input, taking into account the immediate context and the animal's experience.

The vast majority of neurons in the brain are __, which makeonly local connections. Motor output relies on neurons that extend out of the processing centers in bundles called __ and generate output by triggering muslce or gland activity.
- For example, __ transmit signals to muscle cells, causing them to contract.

In many animals, the neurons that carry out integration are organized in a __, which includes the brain and a longitudinal nerve cord.

THe neurons that carry info into and out of the (other system) constitute the __.

The ability of a neuron to receive and transmit info is based on a highly spevcialized cell organization. Most of a neuron's organelles, including its nucleus, are located in the __. A typical neuron has numerous __, highly branched extensions that receive signals from other neurons.

A neuron also has a signle__, an extension that transmits signals to other cells. __ are often much longer than __, and some, are over a meter long.

The cone-shaped region of an axon where it joins the cell body is calledd the __; this is typically the region where the signals that travel down the axon are generated. Near its other end, the axon usually divides into several branches.

Each branched end of an axon transmits info to another cell at a junction called a __. The part of each axon branch that forms this specialized junction is a __.

At most synapses, chemical messenges called __ pass info from the transmitting neuron to the receiving cell. Ind escribing a synapse, we refer to the transmitting neuron as the __ and the neuron, muscle, or gland cell that receives the signal as the __.

To function normally, the neurons of vertebrates and most invertebrates require supporting cells called __. Depending on the type, __ may nourish neurons, insulate the axons of neurons, or regulate the extracellular fluid surrounding neurons. Overall, __ outnumber neurons in the mammalian brain 10-to-50 fold.