Textbook
page 351-353
Structure
of neurons
- has
cell membrane, cytoplasm, mitochondria, nucleus
-
transmits nerve impulses
- different
neurons = different shapes and sizes
4 common features = dendrites, cell
body, axon, branching ends
Dendrites
- receive nerve impulses from neurons/sensory receptors and passes the impulse
to cell body
Cell
Body - contains nucleus; site of metabolic reactions; processes input of
dendrites (if large enough, passes to axon)
Axon
- conducts impulse away from body
Myelin sheath = insulating layer
around axon of some neurons
protects neurons and speeds rate
of nerve impulse transmission
Schwann cells = type of glial cell,
form myelin by wrapping around axon
Classifying
Neurons
1.
Structure - 3 types: multipolar,
bipolar, unipolar neurons
2.
Function -3 types: sensory neurons,
interneurons, motor neurons
The
Reflect Arc
Reflexes - involuntary responses to certain stimuli
Reflex arcs - connections of neurons explaining reflexive
behaviour
- 3 neurons to transmit messages = fast reflexes
(from brain to spinal cord)
1. stimulus (cactus needle) - receptors in skin sense
pressure
2. initiates impulse in sensory neuron
3. activates interneuron in spinal cord
4. signals motor neuron to withdraw hand
