Nervous System Flashcards
What is the definition of the nervous system?
A highly complex system that reacts to stimuli and directs the body to respond in an appropriate manner
What are the 3 components of the nervous system?
- Sensory
- Integrative
- Motor
What is the sensory function of the nervous system?
Receptors which detect changes inside and outside of the body and transfer the information to spinal and cranial nerves
What is the integrative function of the nervous system?
Convert information in the sensory neurons to impulses and transmit the impulses to the CNS via peripheral nerves
What is the motor function of the nervous system?
Elicit an appropriate response to stimuli via PNS and effectors
Name 2 examples of effectors
- Muscle
2. Gland
Give a brief account of the reflex arc
- Stimulus arrives at a receptor
- Activation of a sensory neuron
- Information processed in CNS
- Activation of a motor neuron
- Response by an effector
What are the two parts of the nervous system?
- Central Nervous System (CNS)
2. Peripheral Nervous System (PNS)
What parts of the body is the CNS composed from?
- Brain
2. Spinal Chord
What are the three main areas of the brain?
- Cerebrum
- Cerebellum
- Brainstem (Medulla Oblongata / Pons / Midbrain)
How many cranial nerves are found in the PNS?
12 pairs
How many spinal nerves are found in the PNS and where are they located?
31 pairs 8 Cervical 12 Thoracic 5 Lumbar 5 Sacral 1 Coccygeal
Where do the 12 pairs of cranial nerves originate from?
Nuclei present in the brain stem
What is the basic functional unit of the nervous system?
Neuron
What is the role of a dendrite?
Provide receptive surfaces to permit communication by interfaces with processes from other neurons
What is the role of an axon?
Conduct nerve impulses away from the cell body to the synaptic knob where the signal is passed onto adjoining cells
What is the definition of a peripheral nerve?
A bundle of myelinated axons that travel outside the CNS
What is the definition of grey matter?
A number of cell bodies grouped together which appear grey
Where is grey matter found?
The area of the spinal chord surrounding the central canal and on the surfaces of cerebral and cerebellar hemispheres
What is the definition of white matter?
Matter of the nervous system which appears white due to the presence of myelin
What is the definition of a tract?
A group of myelinated axons which travel together within CNS and share a common origin, destination and function
What is the definition of a neucleus?
A group of neuronal cells located in the same area of CNS and sharing the same function
What is the definition of ganglia?
A group of neuronal cell bodies found outside of the CNS as a discrete swelling
What is the difference between a tract and a neucleus?
Tract = Axons Neucleus = Bodies
What is the definition of afferent fibres?
Axons which carry impulses towards the CNS
What is the definition of efferent fibres?
Axons which carry impulses away from the CNS
What is the definition of sulci?
Depressions between the ridges of cerebral hemispheres
What is the definition of gyri?
Ridges between the depressions of the cerebral hemispheres
What are the types of white matter which connect different parts of the brain with each other?
- Association fibres
- Commissural fibres
- Projection fibres
What are association fibres?
Fibres which interconnect areas of the cortex within one hemisphere
What are commissural fibres?
Fibres which cross the midline to connect areas of the cortex in one hemisphere with the same areas in the other hemisphere
What is the biggest use of commissural fibres?
It allows for co-ordination
What are projection fibres?
Fibres which connect cerebral cortex with other centres in the brain and spinal chord
Where do the projection fibres converge?
Converge into a compact bundle called the internal capsule
What does the term mixed nerve mean?
Nerve have both motor and sensory components
Give 2 examples of mixed nerves
- Spinal Nerves
2. Cranial nerves bar those associated with specific senses e.g. CN1 and CN2
Where does the spinal chord typically end?
Inferior boarder of L1
What are the nerve roots which descend past the termination of the spinal chords called?
Cauda Equina
What is the posterior root of a spinal nerve?
The afferent sensory root that carries sensory information to the brain
What is the anterior root of a spinal nerve?
The efferent motor root which carries motor information from brain
Where does the spinal nerve emerge from?
Intervertebral Foramen
From the outside in, what are the three meningeal layers which cover the spinal chord?
- Dura Mater
- Arachnoid Mater
- Pia Mater
What happens to the nerve outside the vertebral column?
It divides into two branches - Posterior and Anterior Ramus
What is the posterior ramus function?
Contains nerves which serve the posterior portions of the trunk and the skin and muscles of the back
What is the anterior ramus function?
Contains nerves which serve the anterior parts of the trunk and upper and lower limbs