Los ch 8
thalamus
-"inner chamber" -a pair of oval masses, is complicated and connected, constitutes 80% of the diencephalon. -It has seven major groups of nuclei on each side
State the function of: pineal gland
-(a gland of the endocrine system) secretes melatonin - a hormone thought to promote sleepiness and in contributing to circadian rhythms -located in the epithalamus
Substantia nigra
-(left and right) - release dopamine to help control muscle activities - loss of these neurons is associated with Parkinson's disease
red nuclei
-(left and right) - connect to cerebellum -rubro spinal -rubro=red -red nucleus to spinal chord - found in midbrain
Name three different structures found in the pons
cerebellar peduncles 1.superior 2. middle 3. inferior
?State the function of the cerebral aqueduct and identify its location
located: midbrain (mesencephalon) function:
Identify the following structures on a two-dimensional image of the medulla (myelencephalon): pyramids; olives; reticular formation; fourth ventricle
slide 21
Midbrain
- extends from pons superiorly to diencephalon
Periaqueductal gray
-midline
Name the cranial nerves with nuclei in the midbrain
CN III. Oculomotor CN IV. Trochlear
nystagmus
- eye drifting -audiologist record/measure this -eyeball positioning is under control of balance organ and CNS system
State the significance of the decussations of the pyramids(lateral corticospinal) (hint: there are two different points of significance)
- inferior to decussation is brain stem -superior to decussation medulla -white matter bulges on anterior surface of medulla; contains lateral corticospinal tracts (clinically most important descending motor pathway in the nervous system - sometimes called "pyramidal tracts"); approximately 85% of these fibers cross (R->L; L->R) -This crossing is known as the "decussation of the pyramids" 1. This is where the sensory and motor information coming from and to the cerebral cortex "crosses over" resulting in contralateral control of motor/sensory information (the right side of the brain controls the left side of the body and vice versa). This is important because damage above that will have contralateral manifestations; below it will be ipsilateral). 2. It is also a clear, visual boundary (albeit arbitrarily) between the medulla and the spinal cord. The decussations of the pyramids is located just superior to the junction between the medulla and the spinal cord.
Name the condition/disorder that occurs when there's a problem in substantia nigra
- loss of these neurons is associated with Parkinson's disease
State the main structures found in each of the divisions of the brain stem
- midbrain (mesencephalon) cerebral aqueduct, reticular formation, tracts, nuclei, cranial nerve nuclei (III, IV), "colorful" nuclei, cerebral peduncles - pons (metencephalon) cranial nerve nuclei (V, VI, VII, VIII), long tracts, reticular formation, 4th ventricle - medulla (myelencephalon) pyramids, olives, reticular formation, cranial nerve nuclei (IX, X, XI, XII)
Name the auditory system and visual system nuclei found in the thalamus
-Auditory: medial geniculate -Vision: lateral geniculate nuclei
olives
-Inferior olivary nuclei - gray matter bulges on anterolateral surfaces of medulla; contains nuclei from proprioceptors in body (muscle and joint positions) connecting to cerebellum
Pons:
-Pons ("bridge") is primary connection to it via three sets of fibers in addition to connections to cerebellum, pons has: - some cranial nerve nuclei (V, VI, VII, and VIII); - has long tracts and their relay nuclei passing through it; - reticular formation; - 4th Ventricle.
Name the two regions of the mesencephalon (midbrain)
-The posterior region is the tectum ("roof") with two large pairs of nuclei: superior colliculi (vision) and inferior colliculi (hearing). -The anterior region is tegmentum of midbrain ("covering") where most of "colorful" nuclei are.
reticular formation
-extensive functional network that runs from medulla to midbrain; actual anatomy spread out and diffuse -achieves functions by using different nuclei
State the function of: habenular nuclei
-involved in emotional responses to odors (Mom's home cooking; the fragrance of that special person) -located in the epithalamus
? thalamus
-lateral gen visual system -medi gen audiotory system
Describe the numbering system, names, and anatomical order of cranial nerves
-numbered in roman numerals *from most superior (I) to most inferior (XII) I. Olfactory II. Optic III. Oculomotor IV. Trochlear V. Trigeminal VI. Abducens VII. Facial VIII. Acoustic/vestibulocochlear IX. Glossopharyngeal X. Vagus XI. Accessory XII. Hypoglossal
Name the gland attached to the hypothalamus
-pituitary gland -pituitary is inferior to hypothalamus
lateral corticospinal
-primary path way (tracts) coming off primary motor strip (pre central gyrus) -once called pyramidal tract
Hypothalamus
-smaller part of diencephalon; located inferior to thalamus on its anterior aspect.
diencephalon
-superior end of Brain Stem - thalamic structures
Name the major nuclei found in the tectum
-tectum=roof - posterior region of the midbrain -two large pairs of nuclei: superior colliculi (vision) and inferior colliculi (hearing)
Name the three "colorful" nuclei found in the tegmentum
-tegmentum="covering" -anterior region of the midbrain 1. red nuclei 2.Periaqueductal gray 3. Substantia nigra
where does sensory stop?
-thalamus is stopping point for all sensory information, with exception of CN I. Olfactory - CN I goes straight to brain
Define cervicomedullary junction and state its significance
-the boundary between the medulla and spinal cord is known as the cervicomedullary junction and it is at the level of the foramen magnum, just inferior to the decussation of the pyramids - "significance" is simply that it is at/below this decussation that contralateral motor control is evident...meaning, motor control for structures inferior to the decussation of the pyramids originate from the contralateral cerebral hemisphere.
State the content of the pyramids
-white matter bulges on anterior surface of medulla; contains lateral corticospinal tracts (clinically most important descending motor pathway in the nervous system - sometimes called "pyramidal tracts"); approximately 85% of these fibers cross (R->L; L->R). -This crossing is known as the "decussation of the pyramids" and it is just superior to the junction of the medulla and spinal cord.
State the two cranial nerves that are technically part of the brain
1. CN I. Olfactory (telencephalon, superior to thalamus) 2. CN II. optic (diencephalon) -both contained within dura, not outside the meninges
List the two purely sensory (afferent) cranial nerves
1. CN I. olfactory 2.CN II. optic
Describe the two general functions of the reticular formation
1. In this region (medulla), RF involved in motor and autonomic functions (for example, in maintenance of respiration, cardiac function) 2. In more superior region (midbrain), RF involved in maintenance of consciousness and alertness
?List at least four functions of the thalamus
1. Thalamus is the major relay station for most sensory impulses (not olfactory) going to cerebral cortex from spinal cord and brain stem. Auditory: medial geniculate nuclei; Vision: lateral geniculate nuclei. 2. Also, relay for motor function, relaying information from cerebellum and basal ganglia to primary motor area of cerebral cortex (movement: ventral anterior and ventral lateral nuclei). 3. And, also, contributes to ANS functions, emotions, alertness, and maintenance of consciousness (anterior, medial, and lateral nuclei)
State the two main components of the metencephalon
1. cerebellum 2. pons
State the three functions of that a cranial nerve could serve.
1. sensory 2. motor 3. both
Name the three tracts that connect the cerebellum to the brain stem
1. superior 2. middle 3. inferior *cerebellar peduncles
State the three cranial nerves that control the eyeball muscles and state why these are particularly relevant to audiologists
1.CN III. Oculomotor 2.CN IV. Trochlear 3. CN VI. Abducens
State the number of pairs of cranial nerves
12 pairs
State the total number of cranial nerves
24
Identify the following structures on a two-dimensional image of the mesencephalon (midbrain): tectum, tegmentum
31 and 32
Identify these three functions for all twelve cranial nerves
CN I Olfactory - sensory CN II Optic - sensory CN III Oculomotor - primarily motor CN IV Trochlear - primarily motor CN V Trigeminal - mixed CN VI Abducens - primarily motor CN VII Facial - mixed CN VIII Vestibulocochlear - primarily sensory CN IX Glossopharyngeal - mixed CN X Vagus - mixed CN XI Spinal accessory - primarily motor CN XII Hypoglossal - primarily motor
1st cranial nerve and its functions
CN I. Olfactory - Major sensory function -smell (olfaction): sends info from nasal mucosa to olfactory bulb - sensory -part of brain telencephalon
2nd cranial nerve and its functions
CN II. Optic -Major Sensory Function -Vision: sends message from retina to visual cortex (vision) and superior colliculus (reflexes) - sensory
3rd cranial nerve and its functions
CN III. Oculomotor -major motor function: eye movement; regulation of pupil(constriction), accommodation of lens for near vision, upper lid elevation -primarily motor
4th cranial nerve and its function
CN IV. Trochlear - major motor function: eye movement -primarily motor
Name the cranial nerves with nuclei in the medulla
CN IX Glossopharyngeal CN X Vagus CN XI Accessory CN XII Hypoglossal
9th cranial nerve and its function
CN IX. Glossopharyngeal -major motor function: swallowing - major sensory function: - Taste: posterior third of the tongue; visceral sensation from oral function - mixed sensory and motor
State the cranial nerves that innervate structures that contribute to speech production and swallowing
CN V Trigeminal CN VII Facial Nerve CN IX Glossopharyngeal CN X Vagus CN XII Hypoglossal
5th cranial nerve and its function
CN V. Trigeminal - major motor function: mastication -Major sensory function: -sensation:face, orbit,and oral structures - mixed sensory and motor
Name the four cranial nerves that have their nuclei in the pons
CN V. Trigeminal CN VI. Abducens CN VII. Facial CN VIII. Acoustic/vestibulocochlear
6th cranial nerve and its function
CN VI. Abducens -major motor function: eye movement - primarily motor -controls one muscle: lateral rectus (pulls eye ball to midline/lateral)
7th cranial nerve and its function
CN VII. Facial -major motor function: - facial expressions: secretion of saliva and tears -major sensory function: -taste: anterior 2/3 of the tongue - mixed sensory and motor
State the cranial nerve that innervates most of the muscles of the face
CN VII. Facial Nerve
State the cranial nerve that supports hearing
CN VIII Acoustic/vestibulocochlear
8th cranial nerve and its function
CN VIII. Acoustic/vestibulocochlear -major sensory function: equilibrium and audition - primarily sensory -carries info from auditory system -1/3 comes of auditory
10th cranial nerve and its function
CN X. Vagus -major motor function: phonation & swallowing -major sensory function: -sensation:thoracic and abdominal organs -mixed sensory and motor
11th cranial nerve and its function
CN XI. Accessory -major motor function: head movement and shoulder elevation -primarily motor
12th cranial nerve
CN XII. Hypoglossal -major motor function: tongue movement -primarily motor -nerve below the tongue
Name the two main structures of the diencephalon...and a third as well
Main structures: Thalamus and Hypothalamus Third structure: epithalamus
Name at least one of the nuclei found in the hypothalamus.
Four major regions of nuclei: mammillary; tuberal; supraoptic; and preoptic
List at least four functions of the hypothalamus
Hypothalamus controls many body activities and is a major regulator of homeostasis: Control of the ANS; Production of hormones and connection to pituitary gland; Regulation of emotional and behavioral patterns (rage, agression, pain, pleasure, sexual arousal); Regulation of eating and drinking (contains a thirst center); Control of body temperature (thermostat for blood); Regulation of circadian rhythms and states of consciousness.
which system are the bulk of the cranial nerves in?
Peripheral Nervous System (PNS)
Name the three parts of the epithalamus
Pineal Gland ("pine cone") Habenular nuclei posterior commissure
State the main divisions (i.e., from superior to inferior) of the brain stem.
Superior: Midbrain (mesencephalon) Middle: Pons (metencephalon) Inferior: Medulla (myelencephalon)
? cerebral peduncles
brain stem to brain
what makes up boarder between medulla and spinal chord?
foramen magnum is boarder of medulla and spinal chord
cerebellum
large structure that coordinates motor function; Pons ("bridge") is primary connection to it via three sets of fibers