Lecture 15/ Neuro I

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Bio 220 Lecture 15: Neurobiology I
Campbell, pp.141-142, 960- mid 969

I. Nervous system
We're going to turn now the the second method of comunication that is used to coordinate your parts - the nervous system.

A. Neurons
Neuronsare the cells that transmit signals from one place to another.

48.2

Today we're going to discuss the general structure of neurons and how they work. Neurons are excitablecells; they are able tochange their membrane potential in response to a stimulus.

Ions flow across their membrane, generating an electrical signal. Most cells can't do this; neurons are able to because they have special types of ion channelsin their membrane that respond to changes in electrical activity.

Neurons are made up of a cell bodythat contains the nucleus and organelles and cytoplasmic extensions, called neuritesor processes. These neurites come in two types: dendritesthat collect info from the periphery and bring it to the center and axonsthat transmit info towards the tips.

1. cell body - the nucleus and organelles
2. neurites - extensions or processes
a. dendritescollect info and bring to center (many, short)
b. axonstransmit info towards tips (usually one, long)

Neurons generally have many dendrites, usually about 2 mm long,so that they can collect information from a large area surrounding them. In contrast, they only have one, longer axon. Once the neuron has been stimulated, there is a particular destination that it sends the information to.

A group of neurons is called a nerve.

B. Functional classes of neurons
There are 3 functional classes of neurons:
1. Sensoryneurons bring information in to the CNS from the periphery.


		Bio 220 Lecture 15: Neurobiology I Campbell, pp.141-142, 960- mid 969 I. Nervous system We're going to turn now the the second method of comunication that is used to coordinate your parts - the nervous system.
		A. Neurons Neuronsare the cells that transmit signals from one place to another.
				48.2
		Today we're going to discuss the general structure of neurons and how they work. Neurons are excitablecells; they are able tochange their membrane potential in response to a stimulus. Ions flow across their membrane, generating an electrical signal. Most cells can't do this; neurons are able to because they have special types of ion channelsin their membrane that respond to changes in electrical activity. Neurons are made up of a cell bodythat contains the nucleus and organelles and cytoplasmic extensions, called neuritesor processes. These neurites come in two types: dendritesthat collect info from the periphery and bring it to the center and axonsthat transmit info towards the tips. 1. cell body - the nucleus and organelles 2. neurites - extensions or processes a. dendritescollect info and bring to center (many, short) b. axonstransmit info towards tips (usually one, long) Neurons generally have many dendrites, usually about 2 mm long,so that they can collect information from a large area surrounding them. In contrast, they only have one, longer axon. Once the neuron has been stimulated, there is a particular destination that it sends the information to. A group of neurons is called a nerve. B. Functional classes of neurons There are 3 functional classes of neurons: 1. Sensoryneurons bring information in to the CNS from the periphery.