Brain And Cranial Nerves Flashcards
Diencephalon 3 regions
- Epithalamus
- Thalamus
- Hypothalamus
Epithalamus
-anterior boundary marked by anterior commissure
(Decussion of cerebral hemisphere)
-Roof of Diencephalon
•Superior to the third ventricle
•Anterior portion contains area of choroid plexus
Pineal gland
-Lies in posterior, inferior portion of Epithalamus
-Endocrine structure that secretes melatonin
•important hormone in regulation of day-night cycles and reproductive functions
Thalamus
- Paired structure forms the walls of the third ventricle
- Final relay point for ascending sensory information that will be projected to the cerebral cortex
- Act as a filter, passing only small portion of arriving sensory information
- Each thalamic region contains nuclei that connect to specific regions of cerebral cortex
Lateral geniculate nucleus
- Receives visual information over the optic tract
- Sends signals to midbrain and occipital lobe (visual cortex)
- Filters our unnecessary visual stimuli
Medial geniculate nucleus
- Relays auditory information from Specialized receptors of the inner ear to auditory area in cerebral cortex (auditory cortex)
- Filters our unnecessary auditory stimuli
Hypothalamus
-The floor of the third ventricle
-A critically important control and integration center
•Monitors several types of sensory input:
1) Visceral sensory information
2) Changes in the composition of the CSF and interstitial fluid.
3)Chemicals in the circulating blood
•Blood rapidly enters the hypothalamus, since region lacks of complete blood-brain barrier
Hypothalamus Functions
- Control cardiovascular and respiratory centers of the Medulla oblongata and pons
- Regulates body temperature
- Secrete hormones that control secretions of the pituitary gland
- Controls hunger thirst
- Subconscious Control of motor patterns associated with rage, pleasure, sexual arousal, feeding
Infundibulum
- Hypothalamic structures
- Narrow stalk extending inferiorly from the hypothalamus
- Connects the floor of the hypothalamus to the pituitary gland.
Mammillary bodies
- Hypothalamic structures
- Control feeding reflexes such as licking and swallowing
Arbor vitae “tree of life”
- branching array of white matter (myelinated axons) of cerebellum
- Axons carry information to/from cerebral neurons and other portions of the CNS
Cerebellar peduncles
- Collections of tracts
- Link the cerebellum with the brain stem, Cerebrum, and spinal cord
Cerebellum two primary functions
1)Adjusting the postural muscles of the body
•Coordinates proprioceptor sensory information and motor activity that support posture
2)Programming and fine-tuning movements
•Compares motor commands for learned movement patterns (muscle memory) with perception of muscle and joint position
•Makes necessary adjustments so action matches intent
Ataxia
- Damage to Cerebellum that can cause disturbance in muscular coordination
- Severe ataxia, individual cannot sit or stand without assistance
-Can result from:
•Permanent damage by trauma or stroke
•Temporary damage by drugs, such as alcohol
Cerebrum
-Largest region of the brain
•Highly developed in primates
-Divided into five lobes on each side:
•Frontal, Parietal, Occipital, Temporal, Insula (only visible from midsaggital)
Gyri and Sulci
-bulges and grooves in surface
Central sulcus
-Deep sulcus dividing frontal lobe from Parietal lobe
Precentral gyrus
-Anterior to the central sulcus
-Contains primary motor cortex
•Controls voluntary movements
Postcentral gyrus
-Posterior to the central sulcus
-Contains primary sensory cortex
•Receives sensory information we are aware of
Lateral sulcus
- Nearly horizontal
- Separates frontal lobe from temporal lobe
Parieto-occipital sulcus
- Visible on medial surface
- Separates The Parietal lobe from the occipital lobe
Decussation & Corpus callosum
- Decussation: occurs in brain stem and spinal cord
- Corpus callosum: is one prominent place where decussation occurs between the hemispheres
How many cranial nerves are there?
12 pairs
Name Cranial nerves in order
1) Olfactory Nerve
2) Optic Nerve
3) Oculomotor Nerve
4) Trochlear Nerve
5) Trigeminal Nerve
6) Abducens Nerve
7) Facial Nerve
8) Vestibulocochlear Nerve
9) Glossopharyngeal Nerve
10) Vagus Nerve
11) Accessory Nerve
12) Hypoglossal Nerve
1) Olfactory Nerve
- Function: sensory (smell) only
- Origin: olfactory epithelium
-Destination: olfactory bulbs
•Axons pass through olfactory foramina of cribriform plate (ethmoid)
2) Optic Nerve
- Function: sensory (vision) only
- Origin: retina
- Destination: Diencephalon, via optic canal (sphenoid) then to occipital lobe
3) Oculomotor Nerve
-Functions: Controls extra-ocular eye muscles
•motor function only
-Destination: extra-ocular eye muscles
•Superior, inferior, and medial rectus
•Inferior oblique
•Levator palpebrae superioris
4) Trochlear Nerve
-Function: controls extra-ocular eye muscles
•Motor Function
-Destination: Superior oblique muscle
5) Trigeminal Nerve
-Function:
• Mixed (sensory and motor) function
•Opthalmic (sensory): sensations from the forehead, eyelids, and nose
•Maxillary (sensory): sensations from lower eyelid, upper lip, and cheek
•Mandibular (motor): controls muscles of mastication
6) Abducens Nerve
-Function: controls eye movements
•Motor Function
-Destination: Innervates the Lateral rectus eye muscle
7) Facial Nerve
-Function: Mixed (sensory and motor)
•Sensory: sensations from the face/ taste
•Motor: controls muscles of the face
-Sensory Origin:
•taste buds
-Motor Destination:
•Somatic motor: muscles of facial expression
•Visceral Motor: lacrimal glands, nasal mucous glands, submandibular/submaxillary salivary glands, middle ear
8) Vestibulocochlear Nerve
-Function:
•sensory: balance and hearing
-Origin: receptors of the vestibule and cochlea
•Vestibular branch: balance
•Cochlear branch: hearing
9) Glossopharyngeal Nerve
-Function: mixed (sensory & Motor)
•Sensory Function: tongue pain, blood pressure, dissolved gasses
•Motor Function: Involuntary muscles of swallowing
-Sensory Origin:
•Sensory: posterior 1/3 of the tongue, carotid sinus (blood pressure, dissolved gasses)
-Motor Destination:
•Visceral Motor: parotid salivary gland
•Somatic motor: pharyngeal muscles for swallowing
10) Vagus Nerve
-Function:
•Sensory: information from organs
•Motor: sends information to the organs
-Sensory Origin:
•Sensory: from the visceral organs (to autonomic centersof Medulla Oblongata)
-Motor Destination:
•Visceral Motor: respiratory, cardiovascular, and digestive organs
11) Accessory Nerve
-Function:
•Motor only
-Destination: •Sternocleidomastoid •Trapezius •Pharynx (voluntary muscles of swallowing) •Vocal cords
12) Hypoglossal Nerve
-Function:
•Motor: controls tongue movement
