The Human Nervous System Flashcards
(50 cards)
What is the human nervous system split into?
The central nervous system
The peripheral nervous system
What is the central nervous system?
Brain
Spinal cord
What is the peripheral nervous system?
Somatic nervous system
Autonomic nervous system
What are the main regions of the central nervous system?
Cerebrum
Cerebellum
Brain stem
Spinal cord
What splits the cerebrum?
Deep sagital fissure
What does the cerebellum do?
Movement centre
Has connections to both brain cerebrum and spinal cord
What does the brain stem do?
Relays information from the cerebrum to the spinal cord and cerebellum and vice versa
Regulates functions such as breathing, consciousness and temperature
Most vital for life, damage here causes rapid death
What does the spinal cord do?
Information from the skin, joints and muscles to the brain and vice versa
Spinal cord communicates via spinal nerves
What does the dorsal root of a spinal nerve do?
Brings information into the spinal cord
What does the ventral root of the spinal nerve do?
Carries information away from the spinal cord
What is the Magendie-Bell law?
The finding that the anterior spinal nerve roots contain only motor fibers and posterior roots only sensory fibres Also that nerve impulses are conducted in only one direction in each case
What is the somatic nervous system?
The system which controls voluntary actions
What is the autonomic/visceral nervous system?
The system which controls automatic actions such as breathing
What do visceral sensory axons do?
Bring information about visceral functions to the CNS
Eg. pressure and oxygen content of blood
What do visceral motor fibres do?
Command the contraction and relaxation of muscles in the walls of the intestines and blood vessels
Control the rate of cardiac muscle contraction
Control secretory function of various glands
Where do somatic motor axons derive from?
Motor neurons in the ventral spinal cord
Where do somatic sensory axons enter the spinal cord?
Via the dorsal roots
What is a dorsal root ganglion?
The somata of the dorsal roots which lie outside the spinal cord in clusters
One for each spinal nerve
Structure of a peripheral nerve
Each axon is wrapped and bundled with others in fascicles
Myelinated by Schwann cells
Surrounded by endometrium
Bundled into fascicles by perineurium
What myelinates nerves in the peripheral nervous system?
Schwann cells
What is the peripheral nerve axon surrounded by?
Endoneurium
What bundles axons into fascicles?
Perineurium
What encloses the fascicles and with what?
Enclosed by epineurium
With blood vessels
How many cranial nerves are there?
12 pairs
