Brain Flashcards
The hemispheres are connected by a thick bundle of nerve fibers called the?
Corpus callosum
The brain has how many internal chambers? And what are they called?
4, ventricles
How many % of the blood goes to the brain?
15%
How many % of the total oxygen and glucose is consumed by the brain?
20%
Which substances does the brain barrier system (BBS) allow to pass through?
Water, glucose, oxygen, carbon dioxide, alcohol, caffeine, nicotine and anesthetics
The embryonic hindbrain differentiate into two subdivisions, which 2?
The myelencaphalon and metencephalon
How many of the nerve fibers travelling between the brain and spinal cord are found in the medulla oblongata?
All of them
Which 4 centers does the medulla contain which are responsible for basic physiological functions?
- Cardiac center - which regulates the rate and force of the heartbeat
- Vasomotor center - Regulates blood pressure and flow by dilating and constricting blood vessels
- 2 respiratory centers - Regulates the rate and depth of breathing and others involved in speech, coughing, sneezing, salivation, swallowing, gagging, vomiting and sweating
About 90% of the corticospinal tract cross over to the opposite side of the brainstem (medulla oblongata) at the point called the?
Pyramidal descussation
What is the tectospinal tract responsible for?
- Carrying motor signals to the cervical spinal cord
* Mediating movement of the head and neck
What is the posterior spinocerebellar tract responsible for?
Carrying sensory information destined for the cerebellum
What is the 4th ventricle?
A CSF- filled space between the medulla and cerebellum
The 9-12th cranial nerves begins or ends in?
Medulla oblongata
Where does the trigeminal nerve emerge from, and where does it extend through?
- Pons
* Extends into the medulla
What are the sensory functions of cranial nerve IX to XII?
Touch, pressure, temperature, taste and pain
What are the motor functions in cranial nerves IX to XII?
Chewing, swallowing, speech, respiration, cardiovasuclar control, gastrointestinal motility and secretion, head, neck and shoulder movements
What is the Olfactory nerve (CN1) responsible for?
Sense of smell
Where does the fasicles from the olfactory nerve (CN1) attach to?
In the roof of the nasal cavity
What is the optic nerve (CN2) responsible for?
Vision
What is the oculomotor nerve (CN3) responsible for?
- Controls the muscles that turn the eyeball up, down, medially
- Controls the iris, lens and upper eyelid
What is the origin of the olfactory nerve (CN1)?
Olfactory muscosa in nasal cavity
What is the effect of damage of the olfactory nerve (CN1)?
Impaired sense of smell
What are clinical tests for olfactory nerve?
Test if they can identify smells, such as coffee, vanilla, soap etc.
What is the origin of the optic nerve?
Retina
What is the termination point for the optic nerve (CN2)?
Thalamus and midbrain
What is the cranial passage for the optic nerve (CN2)?
The optic foramen
Signs of damage the the optic nerve (CN2)?
Blindness in part or all of visual field
Where is the origin of the oculumotor (CN3) nerve?
Midbrain
Where is the termination of the oculomotor nerve (CN3)?
Somatic fibers to levator palpebrae superioris, superior, medial and inferior rectus muscles; and inferior oblique muscles of the eye
Where is the cranial passage for the oculomotor nerve? (CN3)
Superior orbital fissure
What are signs of damage to the oculumotor nerve? (CN3)
- Drooping eyelid
- Inability to move eye in some directions
- Tendency of eye to rotate laterally at rest
- Double vision
- Difficulty focusing
What are some clinical tests which could be done for the oculomotor nerve? (CN3)
- Look for difference in size, and shape of right and left pupils
- Test pupillary response to light
- Test ability to track moving objects
What is the trochlear nerve (CN4) responsible for?
Controls a muscle that rotates the eyeball medially and slightly depresses the eyeball when the head turns
Where does the trochlear nerve (CN4) originate?
Midbrain
Where does the trochlear nerve (CN4) terminate?
Superior oblique muscle of eye
What is the cranial passage for the trochlear nerve (CN4)?
Superior orbital fissure
What are signs of damage to the trochlear nerve (CN4)?
- Double vision
- Inability to rotate eye inferolaterally
- Eye points superolaterally
- Subject tends to tilt head towards the affected side
What are the clinical test to test the trochlear nerve (CN4)?
Test ability of eye to rotate inferolaterally
What is the function of the trigeminal nerve (CN5)?
It is the most important sensory nerve of the face. Also the largest nerve except for the optic nerve
The trigeminal nerve (CN5) forks into three divisions, which?
- Ophthalmic
- Maxillary
- Mandibular
Is the ophthalmic divison of the trigeminal nerve (CN5) primarily motoric, or sensoric?
Sensoric
Is the maxillary divison of the trigeminal nerve (CN5) primarily motoric, or sensoric?
Sensoric
Is the mandibular divison of the trigeminal nerve (CN5) primarily motoric, or sensoric?
Mixed
What is the function of the ophthalmic nerve?
- Touch
- Temperature
- Pain sensation from upper face
What is the function of the maxillary nerve?
- Touch
- Temperature
- Pain sensation from lower face
What is the function of the mandibular nerve?
- Touch
- Temperature
- Pain sensation on lower face
- Motor function of mastication
What is the origin of the ophthalmic nerve?
Superior region of face
- Surface of eyeball
- Lacrimal (tear) gland
- Superior nasal mucosa
- Frontal and ethmoid sinuses
What is the origin of the maxillary nerve?
Middle region of face
- Nasal mucosa
- Maxillary sinus
- Palate; upper teeth and gums
What is the origin of the mandibular nerve?
Inferior region of face
- Anterior 2/3 of tongue
- Lower teeth and gums
- Floor of mouth; dura mater
- Motor: Pons(??)
Where is the termination of the ophthalmic nerve (CN5)?
Pons
Where is the termination of the maxillary nerve?
Pons
Where is the termination of the mandibular nerve division?
Sensory: Pons Motoric: * Anterior belly of diagstric * Masseter * Temporalis * Mylohyoid * Pterygoid * Tensor tympani muscle of middle ear
Signs of damage to the opthalmic nerve?
Loss of sensation of upper face
Signs of damage to the maxillary nerve?
Loss of sensation from middle face
Signs of damage to the mandibular nerve?
Loss of sensation lower face, impaired chewing
Clinical tests for ophthalmic nerve?
Test corneal reflex (blinking in response to light touch to eyeball)
Clinical test for maxillary nerve?
Test sense of touch, pain, and temperature
Clinical test for mandibular nerve?
- Assess motor function by palpating masseter and temporalis while subject clenches teeth
- Test ability to move mandible from side to side and to open mouth against resistance
What is the primary function of abducens nerve (CN6)?
Controls a muscle that turns the eyeball laterally
Where is the origin of the abducens nerve?
Inferior pons
Is the abducens nerve primarily motor or sensoric?
Motor
Where does the abducens nerve terminate?
Lateral rectus muscle of eye
Signs of damage to the abducens nerve?
- Inability to turn eye laterally
* At rest the eye turns medially because of action of antagonistic muscles
Clinical test for abducens nerve?
Test lateral eye movement
What is the primary function of the facial nerve (CN7)?
Major motor nerve of the facial muscles
The facial nerve divides into 5 braches, which?
Temporal, zygomatic, buccal, mandibular, and cervical
Is the facial nerve primarily motoric, or sensoric?
Mixed
What are the functions of the facial nerve?
Sensory: Taste
Motor: Facial expression
Secretion of tears, saliva, nasal and oral mucus
Where is the origin of the facial nerve?
Sensory: Taste buds of anterior 2/3 of tongue
Motor: Pons