The Nervous System Flashcards
What does the CNS consist of?
Spinal cord and brain
What does the PNS consist of?
Somatic nervous system
Autonomic nervous system
What can the autonomic nervous system be split into?
Sympathetic
Parasympathetic
What sort of actions is the somatic nervous system involved in?
Conscious/voluntary actions
What sort of actions is the autonomic nervous system involved in?
Involuntary actions
Which part of the nervous system conveys sensory information to the CNS and motor output to the effectors?
The PNS
What is a collection of neuronal cell bodies in the CNS called?
Nucleus
Where is the cerebellum located? What is function of the cerebellum?
At the back and bottom of the brain
For motor control
What are nerves running along the length of the CNS (spinal cord) called?
Tracts
How do nerves emerge from the CNS?
Around 30 pairs of nerves emerge from the the CNS, 1 on each side of the spinal cord
What is a ganglion?
A collection of neuronal cell bodies in the PNS
What is the cerebral cortex?
The layer of grey matter forming the superficial layer of the brain
What is the structure of the brain with regards to grey and white matter?
Grey matter in the middle of each hemisphere of the brain
White matter on the outside of that
A further thin layer of grey matter outside of that
What does grey matter consist of?
Neuronal cell bodies
What does white matter consist of?
Nerve fibre axons
What is the purpose of white and grey matter? Where does the majority of information processing happen?
To send information along the CNS
Majority in the grey matter
What is the structure of the spinal cord with reference to grey and white matter?
Grey forms a ‘butterfly’ structure in the centre of the spinal cord around a central canal
White matter on the outside of this
What are the two aspects of the spinal cord?
Dorsal and ventral aspects
Which root of the spinal cord do sensory neurones run in?
The dorsal root
Where are cell bodies of sensory neurones found?
Dorsal root ganglion
What do the dorsal and ventral roots of the spinal cord combine to form? Which neurones run here?
A spinal nerve
Both sensory and motor neurones
What neurones run in the ventral root?
Motor neurones
What type of neurones are sensory neurones? What is the advantage of this?
Pseudounipolar cells
Faster transmission of impulses, cell body doesn’t get in the way
What type of neurone is a motor neurone?
Multi polar neurone
Which neurones run between sensory and motor neurones in the grey matter of the spinal cord?
Inter-neurones.
What are the extensions of the cytoplasm of the cell body of a motor neurone called?
Dendrites
What is the structure of a spinal fibre?
Consists of many nerve fibres in bundles called fascicles
Around each fascicle of nerve fibres there is…
Perineurium
Around each individual nerve fibre there is…
Endoneurium
Around the whole spinal fibre there is…
Epineurium
Epineurium, perineurium and endoneurium are examples of which type of tissue?
Loose CT
The cells of the nervous system can be grouped into which two categories?
Neurones
Glial cells
What are 4 examples of glial cells?
Astrocytes
Microglia
Schwann Cells
Oligodendrocytes
What role do microglia play in the nervous system?
They survey the CNS for pathogens and effectively become macrophages when activated
What role do Schwann cells play in the nervous system?
They myelinate axons in the PNS
How many axons can one Schwann cell myelinate?
1 axon
What are the roles of non-myelinating Schwann cells?
They surround many axons for support
Axons become invaginated into Schwann cell structure but not insulated
What are oligodendrocytes?
Found in the CNS
Myelinate multiple axons
What role do astrocytes play in the nervous system?
Act as cellular vacuums
e.g can act at synapses with its long processes to vacuum excess transmitter
How is the blood brain barrier formed?
By interaction of astrocytes with endothelial cells to form tight junctions
