Nervous System Flashcards
Neurones are arranged so that they make up the CNS consisting of what? name items that make up CNS
Brain Spinal cord Peripheral nervous system Ganglia
The Nervous system is formed from specialist cells called what
Neurones
Neurones can be either
sensory (afferent)
or
motor (efferent) in function
Sensory neurones take messages from where
Sensory neurones take messages from the environment via the skin, or sense organs like muscles and joints, and transmit them via the spinal cord to the brain
Motor neurones transmit impulses from where?
Motor neurones transmit impulses from the brain via the spinal cord to the effector, perhaps a muscle, to initiate movement.
There are three main component parts to a neurone:
what are they?
Cell Body
Axon
Dendrites
There are how many types of neurones, all containing the three major components. However they have different appearances and functions
4
Association neurones are responsible for what?
Association neurones are responsible for joining sensory (aferent ) and motor (efferent ) neurones together.
They are found only in the brain and spinal cord and play an important role in reflex processes.
Unipolar neurones
This type of neurone has only ——- —————– process, shared by both —— and ———–.
They are ————– in function and are found primarily within the ——— of ——— and ——— nerves.
Unipolar neurones
This type of neurone has only one cytoplasmic process, shared by both axon and dendrite .
They are sensory (aferent ) in function and are found primarily within the ganglia of cranial and spinal nerves.
Multipolar neurones
This type of neurone has many cytoplasmic processes, only one of which is an axon, there will be several more as dendrites .
These neurones are ——————in function and the majority of neurones within the ——-and ——— are of this type
Multipolar neurones
This type of neurone has many cytoplasmic processes, only one of which is an axon, there will be several more as dendrites .
These neurones are motor in function (efferent ) and the majority of neurones within the brain and spinal cord are of this type
Bipolar neurones
This type of neurone has ——- ———— processes, one —-and one ———-
Bipolar neurones are usually —————) and are found mainly in the ——– of the ——-, the ————–( and the inner—–.
Bipolar neurones
This type of neurone has two cytoplasmic processes, one axon and one dendrite.
Bipolar neurones are usually sensory (afferent ) and are found mainly in the retina of the eye, the olfactory region (nose) and the inner ear.
What do I need to know about neuroglia?
Neuroglia
Cells of the nervous system that are specialised to perform the functions of connective tissue. The neuroglia of the central nervous system are the astrocytes, oligodendrocytes, microglia and ependyme; neuroglia of the peripheral nervous system include the neurolemmocytes (Schwann cells) and the ganglion satellite cells. Also called glial cells.
Neuroglia has two specific properties
1 Irritability ability to generate impulses as a result of stimuli from inside or outside the body
2 Conductivity ability to transport the impulses from one part of the body to another
Synapses and neurotransmitters
Synapses and neurotransmitters
More than one neurone is required to transport an impulse from its origin to its destination, whether it is sensory (afferent) or motor (efferent ). However neurones are not anatomically joined in any way to each other, there is always a minute gap, the synaptic cleft, between them. The synaptic end bulb of each axon terminal is in close proximity to the dendrite receptors or cell bodies of the next neurone in the process, separated only by the synaptic cleft.
(afferent) means what?
sensory
(efferent ).means what?
motor
Neurilemma
The fibres of the ———- ———-are covered in a ———- called neurilemma.
This neurilemma is responsible for the regeneration of fibres that have become injured.
Fibres of the ——- ——— ———— do not have this layer and so do not have any powers of regeneration.
Neurilemma
The fibres of the peripheral nerves are covered in a membrane called neurilemma.
This neurilemma is responsible for the regeneration of fibres that have become injured.
Fibres of the central nervous system do not have this layer and so do not have any powers of regeneration.
Myelin sheath
Some neuroglia produce a phospholipid substance called myelin sheath that surrounds the nerve fibres of the system.
Its function is to increase the ——– at which impulses travel along the fibres, whether they are ——— or ——-.
The myelin sheath has gaps along its length called “—— of ——-“ which also help rapid transmission of impulses along the length of the fibre.
Myelin sheath
Some neuroglia produce a phospholipid substance called myelin sheath that surrounds the nerve fibres of the system.
Its function is to increase the speed at which impulses travel along the fibres, whether they are dendrite or axon .
The myelin sheath has gaps along its length called “nodes of Ranvier” which also help rapid transmission of impulses along the length of the fibre.
Schwann cell
——— and ——— are both formed from the same cell, the Schwann cell.
This Schwann cell encircles the fibre as it develops and continues to wrap itself around the fibre in a swiss roll effect. The nucleus and the cytoplasm of the cell are forced to the outside of the roll and it is this layer that forms the neurilemma.
The myelin sheath is merely many layers of Schwann cell membrane.
Schwann cell
Myelin sheath and neurilemma are both formed from the same cell, the Schwann cell.
This Schwann cell encircles the fibre as it develops and continues to wrap itself around the fibre in a swiss roll effect. The nucleus and the cytoplasm of the cell are forced to the outside of the roll and it is this layer that forms the neurilemma.
The myelin sheath is merely many layers of Schwann cell membrane.