Neurons communicate quickly Flashcards
(19 cards)
What does the nervous system do?
Coordinates all our voluntary and involuntary actions
In a neuron what are the dendrites?
Short extensions that receive and carry nerve impulses/ messages/ signals from other cells
In a neuron what is an axon?
A single, long extension of the cell body. The axon carries nerve impulses away from the cell body. The length varies greatly. Closer to the brain they can reach up to a few mm and from the spinal cord to the foot they can be up to a m to a foot.
What is the myelin sheath?
A fatty material that most axons are covered by. These axons are called the myelinated axons, while some axons dont have it these axons are called the unmyelinated axons.
Where is the myelin sheath formed?
Outside the brain and spinal cord, this sheath is formed by the Schwann cells, those produced and wrap around an axon
What does a myelin sheath do?
Speeds up the action potential, by the nerve impulse jumping from one node of Ranvier to another node of Ranvier (The intervals in the
What is a synapse?
Occurs where the axon terminal of one neuron joins with a dendrite or cell body of another.
At the synapses how are messages carried between the neurons?
The neurons dont actually touch at the synapses, there is a tiny gap, so messages are carried between them through the movement of chemicals called neurotransmitters.
What are the three types of neurons?
sensory/ motor/ and Interneurons
What are sensory neurons?
Afferent or receptor neurons carry messages from the receptor in the sense organs, or in the skin, tot he central nervous system.
What are motor neurons?
Efferent or effector neurons, which carry messages from the central nervous system to the effects, the muscles and glands.
What are interneuron?
Links between the sensory and motor neurons.
What are the 4 structural types of neurons?
Multipolar
Unipolar
Bipolar
Pseudo unipolar
What is a multipolar neurons?
1 axon, multiple dendrites, extending from the cell body. Majority of interneurons in brain and spinal cord, as well as motor neurons that carry messages to skeletal muscles
What is bipolar neuron?
1 axon, 1 dendrite, occurs in the eyes, ears and nose, where they will take impulses from the sense receptors to other cells.
What are unipolar neurons?
1 axon. Not found in humans or any other vertebrates, they carry messages between neurons, and are found mainly insects.
What are pseudo unipolar neurons?
1 axon, 2 extensions, have both attributes of unipolar and bipolar neurons. They carry messages to the spinal cord and are found in the spinal cord.
What is the conduction of a nerve impulse?
A nerve impulse is an electrochemical change that travels along a nerve fiber. It involves a charge in electrical voltage, and it is bought about by changes in chemicals (Specifically the concentration of ions inside and outside the cell membrane of the neuron)
