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