Nervous System Flashcards
What are the 2 divisions of the nervous system ?
The CNS and the PNS
CNS
Central Nervous System
PNS
Peripheral Nervous System
What does the CNS consist of ?
The brain and the spinal cord
What does the PNS consist of ?
Cranial and spinal nerves (the remainder of the nervous system outside of the CNS)
What are neurones ?
Functional cells of the nervous system, which conduct small electrical signals based on charge differences across their membranes.
Describe the structure of neurones
Cell body - houses the nucleus
Dendrites - short projections from the cell body
Axons - a single long extension
How do neurones communicate ?
Via neurotransmitter release at synapses
What is a collection of cell bodies called ?
Ganglion (ganglia)
What are axons covered by ?
A myelin sheath, which is made up of lipids
Function of myelin sheath
Speeds up the conduction of electrical impulses
What are structures in the CNS covered in ?
Protective layers of meninges
What are the 3 layers of meninges ?
Dura mater
Arachnoid mater
Pia mater
Dura mater
Tough outer layer
Arachnoid mater
Middle layer, creates a subarachnoid space for cerebrospinal fluid.
Pia mater
Closely adhered to brain/spinal cord
How many paired spinal nerves are there ?
31 pairs
What are the 31 spinal nerves ?
8 cervical
12 thoracic
5 lumbar
5 sacral
1 coccygeal
How many paired cranial nerves are there ?
12 pairs
Where do the cranial nerves arise from ?
The brain/ brainstem
Where do the cranial nerves function ?
Mostly occur in the head and neck, with the exception go the vagus nerve.
What can the PNS be further divided into ?
Autonomic nervous system
Somatic nervous system
Autonomic nervous system
Self governing
Sympathetic and parasympathetic divisions
Sympathetic nervous system function
Activated by ‘fight or flight’ situations
