Download Nervous System 1 A neurotransmitter, i.e. a chemical compound

Nervous System 1
A neurotransmitter, i.e. a chemical compound (substance) that
transmits a nerve impulse from one neuron (nerve) to another. It is
found at the synapse and is discharged after transmission of the
impulse.
In nerve impulse transmission a stimulus must be of a certain 'size'
(threshold) before it will be transmitted. If a stimulus exceeds the
threshold all will be transmitted and if the stimulus does not exceed
the threshold nothing will be transmitted.
Long appendage coming from cell body of nerve cell (neuron).
Conducts impulses away from cell body.
Controls activities of neurons (nerve cell). Contains Nissl's granules
(composed of RNA and used in protein synthesis), nucleus and
mitochondria and produces a neurotransmitter.
A mass of nerve cells (nervous tissue) which co-ordinates the
activities of an animal. In vertebrates it is composed of the brain and
spinal cord.
acetylcholine
all or nothing law
axon
cell body
central nervous
system (CNS)
Outer layer of the cerebral hemispheres. Composed of grey matter.
cerebral cortex
That part of the human brain found above the pons and medulla
oblongata. It is made up of two halves, the cerebral hemispheres,
which are connected together by a band of nerve fibres – the corpus
callosum. It is responsible for movement, sensations, learning,
memory, intelligence and emotions.
cerebrum
Tightly bundled nerve fibres that join the two cerebral hemispheres
of the brain.
corpus callosum
A process (a piece sticking out) of the cell body of a neuron, which
transmits impulses towards the cell body.
dendron
Pairs of projections arise from the spinal cord; these are called spinal
roots of which there are two types. Which one has a swelling, and
carries sensory neurons into the spinal cord?
Carries messages from the central nervous system (CNS) to
effectors. Cell body located at end of axon, inside CNS, e.g. motor
neurons.
dorsal root
efferent neuron
Found in the spinal cord and brain. Consists of nerve cell bodies and
dendrites.
grey matter
Chemical change transmitted along a nerve fibre, which brings about
a response in an effector (muscle or gland).
impulse
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Neurons that carry messages from one or more sensory neurons to
motor neurons. They are found within the central nervous system.
interneurons
Drug used in the treatment of Parkinson’s disease. It is converted
into dopamine by the body.
levodopa
Membranes surrounding the brain and spinal cord.
meninges
Lipid covering formed by the Schwann cells of neuron. Insulation on
dendrites or axons of neurons. Speeds up impulse transmission.
myelin sheath
Chemical change transmitted along a neuron that brings about a
response in an effector.
nerve impulse
Bony projection from a vertebra for muscle attachment.
neural spine
Nerve cell. Bundles of these form nervous tissue. All are basically
similar in structure. Each consists of one axon, one or more
dendrons, neurotransmitter vesicles (pouches) and a nucleus
contained in the cell body. A myelin sheath and Schwann cells may
also be present. There are three types: sensory, motor and inter...
neuron
Constriction of myelin sheath on the axon to separate Schwann cells
on some neurons. Speeds up impulse transmission.
node of Ranvier
Loss of feeling and movement due to damage to a nerve cord or the
central nervous system.
paralysis
All nerves outside the central nervous system (CNS), i.e. all nerves
except the brain and spinal cord. They carry messages to and from
the CNS.
peripheral
nervous system
(PNS)
Nerve cell that carries the impulse (message) away from the
synapse.
postsynaptic
neuron
A structure that receives and transmits a stimulus; touch, smell,
taste, pain, etc.
receptor
The pathway from the point of stimulation to the responding
effector. It has five components. The stimulus is picked up by a
receptor (1), that sends the message along an afferent (sensory)
neuron (2), to the spinal cord (3). The reply to this stimulus is sent
from the spinal cord along an efferent (motor) neuron (4), to an
effector (muscle or gland) (5).
reflex arc
Cell found around the axon of a neuron – secretes the myelin
sheath.
Schwann cell
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Afferent neuron. Pick up and carry messages from sense organs
(receptors) to the central nervous system (CNS). Cell body at end of
a short branch to one side of the axon, outside CNS.
sensory neuron
Any change in the environment (internal or external) that causes a
cell or organism to respond.
stimulus
Neurotransmitter swelling. A swelling at the end of an axon.
synaptic knob /
terminal button
The minimum limit/level at which a stimulus is perceptible or
generated.
threshold
Pairs of projections arise from the spinal cord. These are called
spinal roots of which there are two types.
Which type carries motor neurons away from the spinal cord?
ventral root
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