Module 5:Neurones Flashcards
Different neurones and their structures
State the function of neurones in the body
to transmit electrical impulses rapidly around the body so that the organism can respond to changes in its internal and external environment
Name the 7 components of neurones
the cell body
the axon
dendrons-dendrites
myelin sheath
axon terminals
nodes of Ranvier
nucleus
Give the function of dendrons/dendrites
they extend from the cell body and receive impulses from other neurones as well as transmitting impulses towards the cell body
dendrites are the smaller branches attached to dendrons
State the structure of the cell body
make 3 points
it contains the nucleus
the nucleus is surrounded by cytoplasm
it also contains large amounts of endoplasmic reticulum and mitochondria which are involved in producing neurotransmitters
State the structure and function of axons
they are singular , elongated nerve fibres that have a plasma membrane
they transmit nerve impulses away from the cell body
State the function of the myelin sheath
Describe its structure
it insulates the axon which increases the speed of nerve transmission
its made of many layers of plasma membrane
State the function of the axon terminals
these are the points where the neuron communicates with other cells
Name the cells that produce the layers of plasma membrane to form the myelin sheath and how do they do this?
Schwann cells , they do this by continuously growing around the axon
What are the nodes of Ranvier?
What effect do they have on nerve transmission in myelinated neurones?
small gaps located between adjacent Schwann cells
they cause the electrical impulse to ‘jump’ from one node to the next along the axon so the impulse is transmitted much faster
Name the 3 different types of neurone
sensory , relay and motor
Describe the function of sensory neurones and give three features of them
they transmit impulses from a sensory receptor cell to a relay/motor neurone or the brain
-they have one dendron that carries the impulse to the cell body
-they have one axon that carries the impulse away from the cell body
-the cell body is located in the middle of the neurone
Describe the function of relay neurones
-do they have short or long axons and dendrons?
they transmit impulses between neurones
they have short axons and dendrons
Describe the function of motor neurones and give 2 features of them
they transmit impulses from a sensory or relay neurone to an effector
they have one long axon and many short dendrites
All sensory receptors have two main specific features , what are they?
they are specific to a single type of stimulus
they act as a transducer
What is meant by a transducer
they convert a stimulus into a nerve impulse
