What are the two main forms of coordination in animals as a whole?
The nervous system and hormonal system.
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What is the nervous system?
They use nerve cells to pass electrical impulses along their length. They stimulate their target cells by secreting chemcials, known as neurotransmitters, directly onto them.
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What is the hormonal system?
The hormonal system produces chemcials (hormones) that are transported in the blood plasma to their target cells.The target cells have specific receptors on their cell-surface membranes and the change in the concentration of hormones stimulates them.
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3 features of the hormonal system?
Hormonal system - transmission by blood stream, response is slow, response is often long-lasting.
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3 features of the nervous system?
Nervous system - transmission is by neurones, response is rapid, response is short-lived.
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What 7 things is the mammalian motor neurone made up of?
A cell body, dendrons (and dendrites), an axon, Schwann cells, a myelin sheath and nodes of Ranvier.
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What is a cell body?
Contains all the usual cell organelles, including a nucleus and large amounts of rough endoplasmic reticulum. This is associated with the production of proteins and neurotransmitters.
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What are dendrons?
These are extentions of the cell body which subdivide into smaller branched fibres, called DENDRITES, that carry nerve impulses towards the cell body.
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What is the axon?
A single long fibre that carries nerve impulses away from the cell body.
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What are Schwann cells?
These surround the axon, protecting it and providing electrical insulation. They also carry out phagocytosis (the removal of cell debris) and play a part in nerve generation.
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What is the myelin sheath?
This forms a covering to the axon and is made up of the membranes of the Schwann cells. These membranes are rich in a lipid known as myelin. Neurones with a myelin sheath are called myelinated neurones.
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What are the nodes of Ranvier?
These are constrictions between adjacent Schwann cells where there is no myelin sheath. These constrictions are 2-3µm long and occur every 1-3mm in humans.
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What three different types of neurones are neurones classified into?
Sensory neurones, motor neurones and intermediate or relay neurones.
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What are sensory neurones?
These transmit nerve impulses from a receptor to an intermediate or motor neurone. They have one dendron that is often very long. It carries the impulse towards the cell body and one axon that carries it away from the cell body.
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What are motor neurones?
These transmit nerve impulses from an intermediate or relay neurone to an effector, such as a gland or a muscle. Motor neurones have a long axon and many short dendrites.
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What are intermediate or relay neurones?
These transmit impulses between neurones, for example, from sensory to motor neurones. They have numerous short processes.
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Other cards in this set
Card 2
Front
They use nerve cells to pass electrical impulses along their length. They stimulate their target cells by secreting chemcials, known as neurotransmitters, directly onto them.
Back
What is the nervous system?
Card 3
Front
The hormonal system produces chemcials (hormones) that are transported in the blood plasma to their target cells.The target cells have specific receptors on their cell-surface membranes and the change in the concentration of hormones stimulates them.
Back
Card 4
Front
Hormonal system - transmission by blood stream, response is slow, response is often long-lasting.
Back
Card 5
Front
Nervous system - transmission is by neurones, response is rapid, response is short-lived.
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