Neurology #2 Flashcards
What are the three meninges connective tissue layers that protect the Central Nervous System from rubbing against the bones of the skull and spine?
Dura Mater
Arachnoid mater
Pia Mater
What is the more tough and fibrous outer layer of the meninges?
Dura Mater
What layer anchors to the skull?
dura mater
What is the more delicate fibrous middle membrane of the meninges?
arachnoid mater
What does the name arachnoid refer to?
It refers to its delicate spider web-like network of collagen fibers.
Which meninges layer is vascularized?
the meninges layer that is vascularized is the pia mater
Which meninges layer firmly adheres to the brain?
pia mater
Where are ependymal cells located?
they line the ventricles of the brain and the central canal of the spinal cord.
How many connecting ventricle cavities are there in the brain?
Four connecting Ventricle Cavities
What are the connecting ventricle cavities of the brain filled with?
Cerebral Spinal Fluid
What is Cerebral Spinal Fluid?
It is a clear, colorless liquid that acts to lesson the impact of a blow to the head
It also serves to transport hormones to other areas of the brain.
What produces cerebral spinal fluid and where does it come from?
Ependymal cells produce
Comes from filtered blood in the ventricles
Where does cerebral spinal fluid circulate?
It circulates in subarachnoid space of the brain and spinal cord.
What moves the cerebral spinal fluid along?
Cilia on the surface of the ependymal cells that extend into the ventricular cavities and move CSF
What is the normal total volume of cerebral spinal fluid?
125-150 ml
How much cerebral spinal fluid is produced a day?
400-500 ml/day
What do dural sinuses do?
they carry reabsorbed CSF back to the blood via the internal jugular veins of the neck.
What is the aka for dural sinuses?
cranial sinuses
Where are dural sinuses located?
They are found between the two layers of the dura mater.
What do the dural sinuses lack?
They lack the 3 tunics of arteries and veins.
When cerebral spinal fluid builds up within the ventricles what is the condition called?
Hydrocephalus
What is the Calvaria made up of?
It is made up of two layers of compact bone separated by a layer of spongy bone called the diploe.
What is the spongy bone between the two layers of compact bone in calvaria called?
diploe
What is the Calvaria?
Is the upper dome like portion of the skull.
What does the calvaria consist of?
frontal, parietal and occipital bones
How is the diploic space drained?
It is drained through the diploic veins and are in turn drained by emissary veins travelling in the parietal and occipital foramina.
Where is the flow of emissary veins always coming from?
the brain
How does the skull cool itself?
by allowing fluids to cool on the surface and then havening them flow back inward to cool the skull
Where can hematoma occur?
Subdural and epidural spaces
What is hematoma?
is a localized mass of extravasated blood, usually clotted.
What is a possible outcome of hematoma?
increase in intracranial pressure can lead to fatal brain tissue damage
What are some symptoms of cerebral hematoma?
Severe headache
deterioration of consciousness
motor dysfunction.
How is hematoma treated?
Holes are promptly drilled for evacuation of the extradural clot.
What can be a cause of hematoma?
A blow to the skull can create an epidural hematoma between the skull and the dura. It can cause a fracture that transects a blood vessel
Which cranial artery is the most susceptible to taking damage?
The meningeal artery
It lies in a groove in a part of the parietal bone that is very thin in the region of the temple.
At what age is a subdural hematoma more common and why?
More common in the elderly because of normal brain shrinkage that occurs. The shrinkage stretches and weakens the bridging veins leaving it more susceptible to leakage
What is a chronic subdural hematoma?
an old collection of blood and blood breakdown products between the surface of the brain and the dura. Blood leaks from the veins slowly overtime.
Does sensory or afferent information get sent or from the PNS?
From the PNS to the CNS
What is proprioception?
the sense of the relative position of neighboring parts of the body without the use of vision.
What is Romberg’s test?
It is a test of the proprioception receptors and pathway function. The patient is asked to close their eyes while standing and if they fall it is considered a positive Romberg’s test
What is exteroception?
It is the perception of the outside world
What is interoception?
Is the perception of bodily sensations including pain, temperature, itch, sensual touch, visceral sensations, hunger, thirst, air hunger, and emotional awareness.
What form does internal and external information take once it reaches the CNS?
Action potential aka neve impulses
What is a sensory receptor?
Sensory receptor is a structure that recognizes a stimulis in the internal or external environment of an organism and converts it into an AP
What is habituation?
Is a decreased CNS response to a repeated stimulus
What sensitization?
Is an increased response to a repeated stimulus
What type of neuron are most sensory receptors attached to?
Unipolar
All Unipolar neurons are attached to what type of receptor?
Afferent receptors/ Sensory receptors
In a unipolar neuron the peripheral axon is always associated with what part?
Sensory receptor
Ina unipolar neuron the central axon always enters where?
The Central Nervous System
What is transduction?
sensory receptors ability to convert stimulus energy into action potentials.
What does depolarization mean?
Signifies that a neuron is in the process of sending a nerve impulse
What is adaption?
The decrease in sensory receptors (PNS) sensitivity during a long last stimulus
Which receptors are termed slow adapting?
receptors which continue to respond throughout the duration of a prolonged stimulus example: nociceptors / pain receptors
What would be some examples of fast adapting cells?
Olfactory receptors
Smell
What is the point in which a sensory receptor can no longer detect a sensation known as?
The absolute threshold
If you can barely hear a sound it is known as?
the absolute threshold
What is a difference threshold?
the smallest amount of change needed in a stimulus before we notice the change.
What does Weber’s law state about what is needed for us to notice a difference between two stimuli?
States the more intense the stimulus, the more it will need to change before we notice the difference
What is a receptive field?
Every receptor has a defined area in the periphery, over which it can receive input
What is spatial discrimination?
The ability to accurately locate the site of stimulation and to detect that neighboring stimuli are actually seperate
Areas with smaller receptive fields and a higher concentration would be more or less sensitive?
More sensitive
What is the two point threshold?
It is the minimal distance in which two separate stimuli can be distinguished as separate
