Nervous System Flashcards
Roughly, how many neurons are there in an individuals body
100 billion
What nervous tissue:
- Receives information
- Communicates information
- Transmits information
- Dendrites
- Synapses
- Axons
What nerves enter into the spinal cord
Peripheral nerves
What is a nerve cell called
A ganglion
What nerves travel away (towards) the CNS
Efferent (afferent)
Where does information from the face travel directly to
The brain stem (not through the spinal cord)
How many pairs of cranial nerves exist and where do they input directly into
12 pairs; directly into the brain/brain stem
How many pairs of spinal nerves exist and where do they input directly into
31 pairs; directly into the spinal cord
What do the cranial and spinal nerves collectively make up
The peripheral nervous system
What are the 2 functional sections of the nervous system and are they voluntary/involuntary
- Somatic (information from the outside world); voluntary
2. Autonomic (information we don’t think about); involuntary
What are the lumps and bumps in the brain called
Gyrus/gyri
What are the indentations through the brain called
Sulcus/sulci
What is the most important function of the cerebellum (little brain)
Controls movement and balance
Name the 3 components that make up the brain stem (start with the most superior)
- Midbrain
- Pons
- Medulla oblongata
What does the brain stem connect
Connects the spinal cord with the cerebral hemispheres
Name the 4 lobes of the brain
- Frontal
- Temporal
- Parietal
- Occipital
What does the longitudinal fissure separate
The left and right cerebral hemispheres
What 2 cranial nerves enter directly into the brain
1 & 2
What does grey matter contain
Neurons; nerve cells/bodies
What does white matter contain
Axons (communication cables) used to talk to separate nerves
What is the region called deep in the brain that contains grey matter
Internal capsule
Where is the grey matter located in the spinal cord
Contained within the centre of the spinal cord; white matter is on the outside
Name the 2 swollen regions of the spinal cord, and why do we need them
- Cervical enlargement
- Lumbar enlargement
Due to the presence of limbs; need lots of neurons to carry out the motor functions
What do the posterior and anterior roots of the spinal cord contain
Posterior = 100% sensory Anterior = 100% motor
What do peripheral nerves consist of
Axons and their supporting cells
What benefit does a myelin sheath bring to an axon
Speed up the electrical signals neurons use to talk to each other (electrical insulator)
What cells produce myelin sheaths
Schwann cells
What does a plexus of nerves exit towards
Towards the limbs
What is a dermatome
Area of skin supplied by the sensory fibres in a given segmental somatic nerve
What is an individual peripheral nerve composed of
Fascicles, which are made up of 100s-1000s of axons
What are the 2 parts of the autonomic nervous system
Sympathetic (“fight or flight”); parasympathetic (opposes everything the sympathetic system does)
Where do the sympathetic nerves enter and exit the spinal cord
Between T1 and L2; restricted to the thoraco-lumbar outflow
What are the sympathetic chains and where do they run
Series of connected ganglia; go from the top to the bottom, and sit either side, of the vertebral column
What nerves emerge from the sympathetic chains
Splanchnic nerves
Where are the parasympathetic nerves restricted to
The cranio-sacral outflow
Where do the vertebral arteries emerge from and what do they form
Subclavian arteries and form the basilar artery
Describe the pathway of the vertebral arteries
Follow the cervical bones and enter through the foramen magnum (where they form the basilar artery)
What areas of the nervous system do the vertebral arteries supply
Much of the:
- Cerebellum
- Brain stem
- Posterior part of the cerebral hemispheres
- Upper spinal cord
What vessels supply the majority (2/3) of the cerebral hemispheres
Internal carotid arteries
What circle of blood vessels connects the vertebral and internal carotid systems
Circle of Willis
Name the 3 layers of connective tissue membrane that cover the CNS (start with deepest)
- Pia mater
- Arachnoid mater
- Dura mater
What gives the brain its shine
Pia mater (few cells thick); follows the lumps and bumps of the brain
What minor vessels drain deoxygenated blood from the brain
Dural venous sinuses
What do the dural venous sinuses drain into
Internal jugular veins
What does the choroid plexus secrete, and how much does it secrete a day
Cerebro-spinal fluid; 400-500ml/day
What is the purpose of cerebro-spinal fluid
Cushions the brain both internally (ventricles) and externally (subarachnoid space)
What allows the CSF to be reabsorbed into the dural venous sinuses
Specialised structures called arachnoid granulations
