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
Symptoms of activation of sympathetic nervous system
Dilated pupils
Increased cardiac output
Increased blood flow to skeletal muscle and brain
Slow digestion
Parasympathetic nervous system function
‘Rest & Digest’ system
Symptoms of activation of parasympathetic nervous system
Constriction of pupils
Decreased cardiac output
Promotion of digestive functions
Where are cell bodies found in sympathetic NS ?
T1 and L3
Where are cell bodies found in parasympathetic NS ?
S2 and S4
What is the axial skeleton ?
Skull, vertebrae, Sacrum, Ribs, Coccyx, Hyoid and Sternum
What is the appendicular skeleton ?
Limbs, Clavicle, Scapula and Hip bones.
