Nervous System Flashcards
What 3 parts make up a neuron?
- Cell body
- Dendrites
- Axon
What do Dendrites do?
Receptive part of the neuron cell. Respond to incoming signals.
What do Axon’s do?
- Send action potentials away to another tissue
- Have synaptic vesicles at the end which release neurotransmitters into synaptic cleft
What is a nerve?
Bundle of axons (motor and sensory) in PNS (peripheral nervous system)
Ex. Sciatic nerve, radial nerve
What is a tract?
Bundle of axons in CNS (central nervous system)
Ex. Brain and spinal cord - ex. lateral spinothalamic tract
What is a ganglion?
Cluster of cell bodies in peripheral nervous system i.e. doral root ganglion
What are neuroglia?
They are the supporting cells of the nervous system. Support neurons. Protect, nourish, remove debris from neurons.
List the six type of neuroglia
- Astrocytes - Form blood/brain barrier
- Oligodendrocytes - Form myelin in CNS
- Schwaan Cells - Form myelin in PNS
- Microglia
- Ependymal Cells
- Satelitte cells
How does a neuron conduct action potential?
- Na+ influx = depolarization
- K+ efflux = repolarization
What are the four main parts of the brain?
- Cerebrum
- Cerebellum
- Diencephalon
- Brainstem
How many hemispheres are in the cerebrum?
Two
What are the 4 lobes in each of the cerebrum hemispheres?
- Frontal
- Temporal
- Parietal
- Occipital - visual cortex
What is Wernicke’s area responsible for in the cerebrum?
Understanding of written and spoken language
Injury causes fluent aphasia - they can respond, but they cannot understand the incoming language
What is Broca’s area responsible for in the cerebrum?
Speech output or speech production.
Injury causes expressive aphasia - they start speaking jibberish
What is the cerebellum responsible for?
It is responsible for coordination, equilibrium and proprioception
What does the Diencephalon contain?
Thalamus
Hypothalamus
Pituitary Gland
Pineal Gland
What is the brainstem responsible for?
Organ regulation
Involuntary - autonomic nervous system
What are the three parts of the brainstem?
- Midbrain (Superior)
- Pons
- Medulla Oblongata (Inferior)
What are the steps of the motor pathway?
- Primary Motor Cortex
- Pyramids of Medulla Oblongata
- Down the spinal cord via corticospinal/pyramidial tracts
- Anterior/Ventral horn
- Anterior/Central Root
- Spinal Nerve
- Peripheral Nerve
- Muscle
What is the neurotransmitter that stimulates the muscle to contract?
Acetylcholine
What is the name of the tract that carries motor impulses down the spinal cord?
The Corticospinal tract or pyramidial tract
Motor nerve impulses exit the spinal cord via which of the following:
A. The Ventral Root
B. Dorsal Root
A. The ventral root
What is the neurotransmitter that motor neurons release?
Acetylcholine
Where do motor tracts cross?
In the pyramids of the medulla oblongota
What are the steps of the sensory pathway?
- Peripheral receptor
- Peripheral nerve
- Spinal nerve
- Posterior/Dorsal Root
- Posterior Dorsal Horn
- Up Spinal cord via Spinothalamic Tract
- Thalamus (Relay Station)
- Somatosensory Cortex
Where do tracts cross?
- Corticospinal tracts cross in the pyramids of medulla oblongata
- Lateral Spinothalamic tract (pain and temperature) cross at the spinal cord level
What makes up the central nervous system?
The brain and the spinal cord
What connective tissue protects the brain and the spinal cord?
The Meninges
What are the 3 layers of the Meninges?
Pad
1. Pia Matar (deepest)
2. Arachnoid Matar
3. Dura Matar (most superficial, thickest, toughest)
What layer of the meninges is the toughest, thickest, strongest?
The Dura Matar
How is Cerebrospinal Fluid formed?
Choroid plexus (capillaries) in ventricles of the brain makes the Cerebrospinal Fluid
How is the cerebrospinal fluid reabsorbed?
Arachnoid villi
What nerves attach directly to the CNS?
- Spinal Nerves
- Cranial Nerves
Which vertebrae is the spinal nerve named for?
General Rule: If you are in the cervical spine the nerve will be above it’s corresponding vertebrae.
Ex. C1 nerve exits above C1 vertebrae.
Thoracic and lumbar spine - the nerve exits below the corresponding vertebrae.
Ex. T1 nerve exists below T1 vertebrae
Olfactory Nerve - Cranial Nerve I
Sense of smell
Optic Nerve - Cranial Nerve II
Sense of vision
Oculomotor Nerve - Cranial Nerve III
Moves eye every other direction, raises eyelid, and constricts the pupil
Trochlear Nerve - Cranial Nerve IV
Moves eye down and in
Which cranial nerves have to do with eye movement?
Cranial Nerves, 3, 4, and 6
Oculomotor nerve - cranial nerve 3
Trochlear nerve - cranial nerve 4
Abducens nerve - cranial nerve 6
Trigeminal Nerve - Cranial Nerve V
Facial sensation, motor for mastication (chewing)
Abducens Nerve - Cranial Nerve VI
Moves eyeball laterally
Facial Nerve - Cranial Nerve VII
Motor for face (expression), Sensory for taste on anterior 2/3 of tongue
Vestibulocochlear Nerve - Cranial Nerve VIII
Hearing and equilibrium (inner ear)
Glossopharyngeal Nerve - Cranial Nerve IX
Motor for swallowing (pharynx) and sensory for taste on posterior 1/3 of the tongue.
Vagus Nerve - Cranial Nerve X
Longest cranial nerve in body. Parasympathetic control of organs. Slows HR, promotes digestive activity/peristalsis
What is the longest AND thickest nerve in the body?
Sciatic Nerve
Accessory Nerve - Cranial Nerve XI
Controls SCM and trapezius (shrug shoulder and turn head)
Hypoglossal Nerve - Cranial Nerve XII
Movement of the tongue
List all 12 cranial nerves
- Olfactory
- Optic
- Oculomotor
- Trochlear
- Trigeminal Nerve
- Abducens
- Facial Nerve
- Vestibulocochlear Nerve
- Glossopharyngeal Nerve
- Vagus Nerve
- Accessory Nerve
- Hypoglossal Nerve
