Brain Flashcards
When referring to the brain what do the directional terms Rostral and caudal mean?
Rostral is towards the forehead and caudal is towards the cord .
During development what do cells from the neural crest differentiate into?
neural sensory cells,sympathetic neurons,Schwann cells, and other types of cells.
What percent of the neurons are in the cerebellum ?
Fifty percent!
How much does the brain weigh?
3 to 3.5 pounds
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What does the longitudinal fissure do?
It separates the left and right hemispheres of the cerebral cortex.
What are the gyri and sulci of the brain?
The Gyri are the folds and sulci are the grooves.
What is the surface layer of grey matter in the brain called?
Cortex
What are the deeper masses of the gray matter called?
nucei
What are bundles of axons ( white matter ) called ?
Tracts
The dura consists of what two layers? What is in between those layers?
Periosteal layer and meningeal layer , in between is the Dural venous sinuses .
True or false there is a epidural space in between the periosteal layer and the cranial bone
False the perisoteal lies close to the bone.
The meningeal layer continue son to the vertebral column and forms what structures?
falx cerebri, tentorium, cerebelli, and falx cerebelli
What is the purpose of the the dural venous sinus? Where does this fluid drain?
collects blood that has circulated throughout the brain (CSF is produced off of this used blood) . The venous sinuses drain into the jugular veins.
What are the symptoms or signs of meningitis?
High fever, stiff neck, drowsiness, and intense headache that may progress into a coma.
How is meningitis diagnosed ?
Diagnosed by examining the CSF . They look at the white blood cells to determine if the infection is viral or bacterial , gram staining will demonstrate if bacterial .
How many ventricles does the brain have ? What are they ?
There are two lateral ventricles, a third and forth
Where are the lateral ventricles located?
There is one lateral ventricle in each cerebral hemisphere .
Where is the third ventricle located?
Beneath the corpus callosum and surrounded by the thalamus
Where is the fourth ventricle located?
between the hemispheres of the cerebellum
Where is the central canal located and what type of cells line the walls?
central canal runs through the spinal cord and is lined with ependymal cells that produce CSF
What are the functions of CSF ?
Buoyancy (floats brain), protection(cushion from hitting the inside of the skull), and chemical stability (rinses away waste)
How and from where does CSF escape?
CSF escapes from the fourth ventricle and surrounds the brain, it is absorbed by arachnoid villa into the venous sinuses
What is another name for the medulla oblangata, cerebellum, pons?
Hindbrain, rhombencephalon
Where are the nuclei of sensory and motor cranial nerves (IX, X, XI, XII)
Medulla Oblangata A.K.A. hindbrain
Where are the nuclei of sensory and motor cranial nerves (V, VI, VII, VIII)
Pons
What two structures in the brain sends and receives information to the motor cortex via the thalamus?
Cerebellum and Basal Ganglia
The output of the _______ is Excitatory while the output of the _______ Inhibitory. The balance between these two systems allows smooth coordinated movement
Cerebellum Excitatory and Basal Ganglia Inhibitory. A disturbance in either system will show up as movement disorders (Parkinson)
What are the three cerebellar peduncles and where do they go?
Superior P to the midbrain, Middle P to the pons, Inferior P to the medulla oblangata
what is the purpose of the superior peduncle on the cerebellum ?
Information to the thalamus and brain stem
What is the function of the cerebellum?
sends corrective feed back to motor cortex (ease dropper) Got information from proprioceptors about actual movements
What is white matter in regards to the cerebellum ?
Arbor vitae
Define Dysmetria
The inability to correctly judge distance . This happens due to cerebellar lesions
Define dysdiadokinesis
inability to carry out fast alternating movements This happens due to cerebellar lesions .
Define Nystagmus
eye condition characterized by rapid , jerky eye movements. This happens due to cerebellar lesions
Define Dysarthria
speech disorder characterized by slow, weak imprecise , and uncoordinated.This happens due to cerebellar lesions
Define Hypotonia
Abnormally low muscle tone .This happens due to cerebellar lesions
What is the main mass of the midbrain?
The Tegmentum
Where is the Tegmentum Located?
It is between the cerebral peduncles and cerebral aqueducts
What does the red nucleus aid in and what muscles does it control ?
It aids in the unconscious regulation and coordination of motor activities. It mostly controls the muscles of the shoulder and upper arm
Why is the red nucleus pink?
Because of a rich blood supply
What do you call the tracts that are from the red nucleus to the cerebellum ?
Rubrospinal tract
Define substantia nigra
A nuclear mass between the tegmentum and cerebral peduncles.
The substantia nigra sends what kind of signals to the thalamus and basal ganglia
Inhibitory signals
Define the location of the Tectum
Roof, dorsal to the cerebral aqueduct
The superiors and inferior colliculi are called what ?
Corpora Quadrigemina
Which colliculi is responsible for reflexive turning the head toward visual input and tracking moving objects ?
Superior colliculus
Which colliculi is responsible for reflexive turning of head to sound
Inferior colliculus
What does the reticular activating system do?
Clusters of gray matter scattered throughout the pons, midbrain & medulla. Regulates balance and posture, allows you to tract moving objects, regulates sleep and conscious attention. Injury leads to irreversible coma
What is another name for the thalamus and hypothalamus?
Diencephalon
Describe the thalamus, what it does, and what system it is involved with (hint: Emotion)
Oval mass of gray matter protruding into lateral ventricle. Receives all sensory information except olfactory. The limbic system
Describe the Diencephalon and its functions
It is the walls & floor of 3rd ventricle. Hormone secretion and pituitary control, autonomic NS control, thermal regulation, Hunger and thirst
What percentage of the brain is the gyri and the sulci?(the two hemispheres )
83%
Why are there folds (gyri) in the cortex?
To fit all dat shit in da brain , increase surface area
What is the purpose of the Frontal lobe?
Voluntary motor functions , planning,mood, smell, and social judgment.
What is the purpose of the Parietal lobe?
Sensory reception and integration of sensory information
What is the purpose of the occipital lobe?
Visual center of the brain .
What is the purpose of the temporal lobe?
Hearing, smell, learning, memory, and emotional behavior.
Most volume of the cerebrum is white matter true or false?
True
What are the three kinds of tracts in the brain
Projection, commissural, association.
Which track forms the internal capsule by extending vertically from the brain to the spinal cord ?
Projection Tracts
The corpus callosum and anterior/posterior commisures are what type of tract?
Commissural tracts , they cross from one hemisphere to the other .
Which tracts connects the lobes and gyri of each hemispheres together.
Association tracts
Which two cells are found in the cerebral cortex? Whatt are their identifying structures ?
Stellate cells, dendrites projecting in all directions and Pyramidal cells, an axon that passes out of the area
Describe the Basal Ganglia and its basic functions
masses of gray matter deep to the cerebral cortex . Its basic functions are receive input from substantia nigra and motor cortex and sends signals back to these regions.
The basal ganglia and the cerebellum are large collections of nuclei that modify what?
Movement
How do the basal ganglia and cerebellum send and receive information to the motor cortex?
They send the information via the thalamus .
The balance between what two systems allows for smooth, coordinated movement . A disturbance in either system will show up as a movement disorder .
Basal ganglia, and cerebellum
Deficit in basal ganglia tend to fall into what two categories?
The presence of extraneous unwanted movements (motor noise) or Absence or difficulty with intended movements
What are the three symptoms associated with Parkinsons ? A lesion to what would cause parkinsons?
Tremors (most apparent at rest), Rigidity (simultaneous contractions of flexors and extensors), And Bradykinesia (difficulty initiating voluntary movement)
What results from the degeneration of the caudate and putamen, also known as, chorea
Huntingtons disease, Is hereditary and causes lesions in the caudate and putamen of the basal ganglia
In the limbic system, what do the amygdala and hippocampus do?
Amygdala is important in emotions and hippocampus in memory, the others purposes are unknown (fornix & cingulate gyrus)
A lesion in the Hippocampus results in ?
Inability to form new memories
In what two regions are emotions formed?
Amygdala and Hypothalamus
Define Somesthesia
Sensory systems associated with the body; includes skin senses and proprioception and the internal organs
What gyrus is the somatosensory in ?
Postcentral gyrus
Explain sensory homunculus
Sections of the postcentral gyrus is proportional to how sensitive that part of the body is
What do association areas interpret ?
Sensory information
What gyrus is the primary motor area?
Precentral Gyrus
What is another name for pyramidal cells ?
Upper motor neurons and they supply muscles of contralateral sides due decussation (cross over)
Explain motor homunculus
Sections of the precental gyrus is proportional to number of muscle motor units in a region
In what Gyrus can you find the Wernicke’s area?
Angular Gyrus, processes text into a form we can speak
What does the Broca’s area generate?
Motor program for larynx, tongue, cheek, and lips
Define Aprosodia and how it is caused
Inability to change ones voice to express common emotions such as anger and sadness, caused right hemisphere brain damage in areas that mirror Broca’s and Wernickie’s
Define expressive Aphasia, a lesion to what area can cause this?
Drunk talk/ slurring entire vocabulary 2-3 words. A lesion to the Broca’s area
Define Receptive Aphasia, a lesion to what area can cause this?
Speech is normal and excessive but makes little sense. lesion to wernicke’s area
Define Anomic Aphasia
Speech and understanding are normal but text and pictures dont make sense
Input & output remains Ipsilateral except for which two cranial nerves?
CN II & IV
Name CN (I), its function and what is impaired if damaged
Olfactory nerve, provides sense of smell; if damaged cause impaired sense of smell
Name CN (II), its function and what is impaired if damaged
Optic nerve, provides vision; damage causes blindness in visual field
Name CN (III), its function and what is impaired if damaged
Oculomotor nerve, provides SOME eye movement (opening of eyelid, constriction of pupil, & focusing)
damage causes drooping eyelid, dilated pupils, double vision, difficulty focusing, & inability to move eye in certain directions
Name CN (IV), its function and what is impaired if damaged
Trochlear nerve, provides eye movement, damage casues double vision and inability to rotate the eye inferolaterally
Where does the CN (II) exit the skull
Optic canal
The Edinger -Westphal nucleus is the source of parasympathetic of what.
The eye, which constricts the pupil and accommodates the lens
Damage to cranial nerve (III) does what to the pupil? why?
The pupil will dilate because the fibers from the Edinger Westphal travel along the (III) CN . Damage could also result in ptosis, and difficult accommodation
Define ciliary muscle and its action, which CN is it associated with?
Thickens the lends when it relaxes , when its flexes the ligaments pull on the lens making it flat (a curved or “thick lens “ bends light in order to see up close , a flat lens is to see a further distance.) CN (III)
Define pupillary constrictor and its action. Which CN is it associated with ?
like a butthole, controls amount of light not the retina by constricting (reducing its diameter). CN (III)
Define Ptosis
Drooping of the eyelid
Define Lateral Strabismus (Exotropia)
Misaligned eye, medial rectus is paralyzed
Define Diplopia
Double vision
Define Mydriasis
Dilated pupil
What CN is the ONLY nerve attached to the dorsal aspect of the brain stem?
CN (IV) Trochlear nerve
Where does the CN IV exit the skull?
superior orbital fissure
Name CN (V), its function and what is impaired if damaged?
Trigeminal Nerve, Main sensory nerve to the face(touch, pain, temperature) and muscles of mastication . Damage produces loss of sensation and impaired chewing.
The CN(V) is a mixed nerve meaning it has both motor and sensory, however it is primarily which one?
Sensory
What forms the trigeminal ganglia?
CN (V)
What three major branches emerge from the trigeminal ganglion ?
Ophthalmic nerve (v1) Maxillary nerve(v2) and mandubular nerve(v3)
Where do the nerves of the trigeminal ganglian exit the skull?
Opthalmic v1 exits through the superior orbital fissure . Maxillary nerve(v2) exits through the foremen rotundum and mandibular nerve exits the skull through foremen ovale
Name CN (VI), its function and what is impaired if damaged?
Abducens nerve , provides eye movement , damage results in inability to rotate eye laterally and at rest rotates medially.
What muscle in the eye does CN (VI) supply? Damage to this eye causes what gaze issue?
Lateral rectus muscle . Medial strabismus
Name CN (VII), its function and what is impaired if damaged?
Facial nerve, provides facial expressions, sense of taste on anterior 2/3 of tongue, salivary glands, and tear, and nasal and palatine glands . Damage produces sagging facial muscles and disturbed sense of taste.
The facial motor nucleus houses what kind of cell bodies?
Muscular efferent nerves
The superior salivatory nucleus houses what kind of cell bodies?
parasympathetic efferent nerves
What kind of cell bodies are found in the geniculate ganglion?
general afferent sensation and taste.
What of all the foremen is the main one the facial nerve(VII) exits ?
stylomastoid foramen
What results in a lower motor neuron lesion to the CN (VII) [facial nerve] ? What is this condition called?
Results in the paralysis of all muscles of facial expression (including those of the forehead) ipsilateral to the lesion. Bell’s Palsy
Name CN (VIII), its function and what is impaired if damaged?
Vestibulocochlear Nerve provides hearing and sense of balance. Damage produces deafness, dizziness, nausea, loss of balance & nystagmus
Name CN (IX), its function and what is impaired if damaged?
Glossopharyngeal nerve, controls swallowing, salvation, gagging, & sensations from posterior 1/3 of the tongue. Also controls blood pressure and respiration. Damage results in loss of bitter and sour taste & impaired swallowing
Name the 5 components of CN (IX) and the foramen it exits the skull from
- Brachial motor 2. Visceral motor 3. Visceral sensory 4. General sensory 5. Special sensory. Jugular foramen
Name CN (X), its function and what is impaired if damaged?
Vagus nerve provides swallowing, speech, & regulation of viscera. Damage causes hoarseness or loss of voice, impaired swallowing, & fatal if both are cut. Exits the skull through the jugular foramen
What CN is the most extensive nerve, consisting of many fibers?
CN (X) Vagus nerve
Does the Vagus effect internal organs ? True or False
True
Name CN (XI), its function and what is impaired if damaged?
Accessory Nerve provides swallowing, head, neck, and shoulder movement. Damage causes head, neck, &shoulder movement [head turns toward injured side] Exits the jugular foramen [along w/vagus]
What CN begins outside of the skull rather than the inside?
CN (XI) Accessory nerve. Enters foramen magnum and exits the jugular foramen. Only nerve to enter and exit the skull
What CN are involved in the gag reflex and how can it be tested?
CN (IX) & (X)
Name CN (XII), its function and what is impaired if damaged?
Hypoglossal nerve provides tongue movements of speech, food manipulation, and swallowing. Damage results in inability to protrude tongue, difficulty speaking, & swallowing
