The Nervous System: Intro Flashcards
White Matter
- Neurons myelinated axon pathway
Gray Matter
- Cluster of neuron cell bodies
Schwann Cells
- Provide the myelin in the peripheral nervous system
Oligodendrocytes
- Myelinate the central nervous system
Disease that Affect Myelinated Cells
- Multiple Sclerosis
2. Gullain-Barre syndrome
Sensory Nerve Fibers (Afferent)
- Cranial nerves and peripheral nerves send information from the head and body to the brain
Sensory Nerves (Afferent) -Cranial Nerves
- Transmit sensory information from the head to the brain
Sensory Nerves (Afferent) -Peripheral Nerves
- Transmit sensory information from the rest of the body to the brain by the spinal cord
Motor Nerves (Efferent)
- The motor output of the brain to the rest of the body
- Cranial nerves innervate various parts of the head
- Peripheral nerves innervate the rest of the body
Motor Nerves
-Vagus Nerve
- Cranial nerve X is an exception:
- One of its roles is communication between the brain and the thoracic and abdominal viscera
Cranial Nerve 1?
-How is it Tested?
- Olfactory
2. Person is asked to sniff aromatic substance like oil or vanilla
Cranial Nerve 2?
-How is it Tested?
- Optic
- Tested with eye chart
- testing point at which person first seen an object
- Inside eye is viewed with ophthalmoscope to observe Blood vessels of interior eye
Cranial Nerve 3?
-How is It tested?
- Occulomotor
- Pupils examined for size, shape, and equality with PENLIGHT
- Ability to follow moving objects
Cranial Nerve 4?
-How is It tested?
- Trochlear
2. Tested in common with Cranial nerve 3 relative to ability to FOLLOW MOVING OBJECTS
Cranial Nerve 5?
-How is It tested?
- Trigeminal
- Sensation of pain, touch and temperature tested with SAFETY PIN & HOT & COLD OBJECTS
- Corneal reflex tested with a wisp of cotton
Cranial Nerve 6?
-How is It tested?
- Abducens
- Tested in common with cranial nerve 3 relative to ability to move each eye laterally
Cranial nerves 3, 4 and 6 are tested together Eye movement
Cranial Nerve 7?
-How is It tested?
- Facial
- Anterior 2/3 of tongue tested for ability to taste:
- Sweet (sugar
- Salty, sour (vinigar)
- Bitter (Quinine) - Check symmetry and facial expressions
Cranial Nerve 8?
-How is It tested?
- Vestibulocochlear (Acoustic)
2. Use a tuning fork to check bone conduction
Cranial Nerve 9?
-How is It tested?
- Glossopharyngeal
- Gag and swallow reflexes checked (tongue blade)
- Posterior 1/3 of tongue may be tested for taste
Cranial Nerve 10?
-How is It tested?
- Vagus
- Same testing as cranial nerve 9.
- Gag reflex… Tongue blade
Cranial Nerve 11?
-How is it Tested?
- Spinal Accessory
- Sternocleidomastoid and trapezius muscles checked for strength by asking subject to rotate head and shrug shoulders against resistance
Cranial Nerve 12
-How is it Tested?
- Subject is asked to stick out tongue
- Any position abnormalities are noted
Upper Motor Neurons
- Travel from the Brain to the Spinal Cord
Lower Motor Neurons
- Travel from the Spinal Cord to the muscle
Upper Motor Neuron Injury
-Signs
- Weakness
- Paralysis
- Spasticity (Muscle is still ok)
- Increased Reflexes (nothing modulates reflexes)
- Babinski Sign (Big toe goes up)
Lower Motor Neuron Injury
-Signs
- Flaccidity (Muscle doesn’t receive any message)
- Decreased reflexes
- Muscle atrophy
- Paralysis
- Weakness
Lesions Above Decussation
-Manifestation
- If a lesion occurs above the decussation of the corticospinal tract in the pyramids, the motor deficit will be on the OPPOSITE SIDE of the body from the lesion
Lesion Below Decussation
-Manifestation
- If a lesion occurs below the decussation EX. (spinal cord or a peripheral nerve), the motor deficit will be on the SAME (ipsilateral) side of the body as the lesion
Sensory Pathways
-2 main Pathways
- Posterior columns
2. Spinothalmic Tracts
Sensory Pathways
-Posterior Columns
- Deals with sensory information
Sensory Pathways
-Spinothalmic Tracts (anterior)
- Motor information communicated through spinothalmic tracts
Proprioception
- Recognizing your body in relation to space
ANS
-Sympathetic
- Adrenergic
2. Mobilizes energy in times of need
ANS
-Parasympathetic
- Cholinergic
2. Conserves and restores energy
Intracranial Pressure
- The Intracranial space is limited, so tumors, edema, and bleeding can elevate intracranial pressure
Intracranial Pressure (Increased) -S/S
- Nausea
- Headache
- Visual changes
- Seizures
- Behavioral changes
- Neurological deficits
Intracranial Pressure
-Treatment
- IV mannitol
- Osmotic that increases osmolarity of blood and draws water from edema into the blood
Increased Intracranial Pressure
-Contraindication
- Lumbar puncture can be dangerous since it can create a negative pressure in the spinal canal
- can precipitate herniation
Cerebral Edema
-Vasogenic Edema
- Caused by INCREASED PERMEABILITY of capillary endothelium of the brain after injury to the vascular structure
CLINICALLY THE MOST IMPORTANT TYPE
Cerebral Edema
-Cytotoxic Edema
- Affect the cellular elements of the brain tissue
-Causes failure of active transport systems
-Cells lose their potassium and gain large amounts of sodium
(mostly happens in gray matter)
Cerebral Edema
-Interstitial Edema
- Caused by transependymal movement of CSF from the ventricles into the extracellular spaces of teh brain tissue
- Increases hydrostatic pressure w/in the WHITE MATTER. Seen most in noncomunicating HYDROCEPHALUS
Hydrocephalus
- Refers to various conditions characterized by excess fluid in the cerebral ventricles, subarachnoid space, or both
Non-Communicating Hydrocephalus
- Congenital Cause
- Obstruction of CSF flow between ventricles
- aqueduct stenosis
- tumor
Communicating Hydrocephalus
- Caused by Infection w/ inflammatory adhesions
2. Impaired absorption of CSF w/in subarachnoid space
