Exam 2 Study Guide

pathway tract

pathway tract

The ________ for visual information starts with the first group of bipolar sensory neurons in the retina (back of eye) Optic nerve exits the posterior of the eye.

Tract

________ is of major importance to speech production.

joint flexes

Rubrospinal: Modulates flexor tone (the amount of tension present in our muscles when ________) in upper extremities.

Function and Parts Spinal Cord

Second order neuron arises from the dorsal horn decussates and then travels to the thalamus (which projects third order neuron to somatosensory cortex) These columns consist of two bundles

fasciculus gracilis (slender bundle) and fasciculus cuneatus (wedge-shaped bundle)

Vascularization

What are the major players in the vascularization

Processed in frontal, parietal and temporal lobe Optic

SA nerve, located at cerebrum not brainstem area, nerve deals with vision

SA nerves, General pathway of cochlear fibers

axons of neurons (bipolar) in cochlea exit as fibers of nerve going to medulla, pass through pons, make synapses in superior olivary complex, and midbrain inferior colliculus, go to thalamus (MGB medial geniculate body) to auditory cortex (temporal lobe)

Gag reflex

IX and X What two go through jugular foramen

Not

P,b, m,n,ng, f,v  motor fibers to all muscles of tongue except palatoglossus muscle (Vagus nerve) what is the limbic system known for

Amygdala

what is it

Major landmarks (label and identify motor/sensory fibers that run through there): dorsal ramus, ventral ramus, spinal nerve, dorsal root, ventral root, dorsal horn, ventral horn, anterior median fissure.

Identify the Four types of fibers

Identify the Four types of fibers Four fiber types: • GSE fibers: to skeletal muscles • GVE fibers: to smooth muscle, heart, glands • GSA fibers: from skin • GVA fibers: from lungs and digestive tract

Where is the pons, medulla, midbrain? • Midbrain – most superior portion • Pons – middle portion • Medulla – lowest portion

Where is the pons, medulla, midbrain?

Label Pons Medulla Midbrain on different views

ventral/anterior

What View is this?

Label: superior and inferior colliculus, middle, inferior, superior peduncles, pineal body, dorsal median sulcus.

Functions of the medulla

• Hosting many cranial nerve nuclei • Autonomic nervous system nuclei like respiratory and swallowing centers • Place for crossing and decussating many motor tracts and sensory tracts • reflexes like coughing, vomiting, gag (nucleus Salitarius) and swallowing (Nucleus ambiguous)

Functions of Pons:

• Bridge for tracts coming from cortex • Hosting cranial nerve nuclei CN V, VI, VII, VIII.

Location of Cerebral Peduncles and Inferior Superior Colliculus

midbrain

The tectum contains what?

• Tectum – superior (vision) and inferior (hearing) colliculi • Cerebral peduncles

Which Cranial Nerves are in the midbrain

CN III, CN IV, CN VI

What is the substantia nigra? Where is it located? What is its function? What is it involved in?

• Substantia nigra: located in midbrain, function: produces dopamine which helps in motor movement and coordination. Involved in Parkinson’s disease.

What is the tegmentum?

• tegmentum is a general area within the brainstem. It is located between the ventricular system and basal / ventral structures at each level of the brainstem. It forms the floor of the midbrain whereas the tectum forms the ceiling. It is a multisynaptic network of neurons that is involved in many unconscious homeostatic and reflexive pathways

Label parts of the brain lateral view:

What are the major players in the vascularization

• Heart • Aorta • Carotid Artery System • Vertebral/Basilar Artery System

There are two main arteries that come of the aortic arc what are they? What do they supply blood to?

External common carotid artery: the muscles of the face, eyes, oral cavity internal: goes toward the brain Left subclavian artery: supplies oxygenated blood to the brainstem

What are the three main arteries that supply blood to the midbrain pons or medulla?

MIDBRAIN (posterior cerebral artery) PONS (basilar artery) MEDULLA (vertebral artery)

Label: vertebral, basilar, posterior spinal artery, superior cerebral artery, posterior inferior cerebellar artery (PICA), anterior inferior cerebellar artery (AICA), anterior spinal artery, middle cerebellar artery, posterior communicating artery, anterior communicating artery, anterior cerebellar artery.

List of arteries and where they supply blood

Basilar artery bifurcates and becomes posterior cerebral arteries. Feeds midbrain, Internal carotid arteries have two main/major branches middle cerebral artery (provides blood for lateral surfaces of brain in frontal lobe and parietal lobe, temporal lobe and to language areas) and ACA anterior cerebral artery Pica aica: cerebellum • Internal Carotid (R/L) – Anterior Cerebral Artery • Medial zones of the frontal and parietal lobes – Middle Cerebral Artery – MCA: lateral aspects of frontal and parietal lobes• Lateral zone of the hemisphere

Major artery supplying the midbrain is the Posterior Cerebral Artery Posterior Cerebral Arteries (R/L) arise from the Basilar Artery • Medial and lateral zone of the occipital lobe • Medial and inferior lateral zone of temporal lobe

what two parts of the brain make up the diencephalon?

Thalamus and hypothalamus

Basal Ganglia parts (three of them)

caudate nucleus putamen and globus pallidus

The circle of willis arteries supply what?

the diencephalon and the basal ganglia

Label the areas of innervation in this image

which two arteries join the circle of willis?

• Internal carotid and basilar artery join the Circle of Willis

what is included in the circle of willis?

Posterior Communicating Artery, Internal carotid, anterior communicating artery, anterior cerebral artery, posterior cerebral artery,

what is not included in the circle of willis?

basilar artery, middle cerebral artery, superior cerebellar artery, vertebral artery

What is the venous drainage system?

• Consists of veins and dural sinuses • Cerebral veins: deep and superficial empty deoxygenated blood into the sinuses • Sinuses collect all the blood and direct it to the internal jugular veins which then take the blood back to the heart

• They can be categorized or separated in terms of function, area of service, and type of fiber. Define each

o Function includes the distinction of general or specific o area of service is divided into visceral and somatic o Type of fiber indicates whether the nerve is a motor (efferent) and sensory (afferent).

What are the twelve cranial nerves?

The twelve cranial nerves include olfactory (CN I), optic (CN II), oclomotor (CN III), trochlear (CN IV), trigeminal (CN V), abducens (CN VI), facial (CN VII), vestibulocochlear (CN VIII), glossopharyngeal (CN IX), vagus (CN X), accessory (CN XI), hypoglossal (CN XII).

What are the nerves involved in speech and hearing?

• CN- V (Trigeminal) • CN- VI (Facial) • CN- VIII (Vestibulocochlear) • CN- IX (Glossopharyngeal) • CN- X (Vagus) • CN- X (Spinal Accessory) • CN- XII (Hypoglossal

What are the sensory afferent nerves?

1 (olfactory),2 (optic),8 (vestibulocochlear)

Where is the first cranial nerve located? what type of fibers carry the information? what is the function?

Olfactory: CN I is at cerebrum, has sensory fibers that brings sensory information (smell) to the brain.

What is the second cranial nerve? where is it located? what does it do?

Optic: SA nerve, located at cerebrum not brainstem area, nerve deals with vision.

Describe the tract/pathway of the optic nerve

The pathway/tract for visual information starts with the first group of bipolar sensory neurons in the retina (back of eye) Optic nerve exits the posterior of the eye. Fibers decussate at the optic chiasm. then the fibers go to the superior colliculus (in midbrain) and some goes to the lateral geniculate body (nucleus) located in thalamus. Then they go to primary visual cortex area which is the occipital lobe.

What is the pathway for the olfactory nerve?

First group of neurons in nasal muscousa in nose and transfer to second group (located in olfactory bulbs) then to the cortex (not stopping by thalamus because that wouldn’t make sense because they would have to go back to the thalamus and back up to the cortex). Processed in frontal, parietal and temporal lobe

Where is the oculomotor nerve located?

Oculomotor: located between pons and midbrain

What are the functions of the 3rd cranial nerve?

All other muscles (superior rectus, medial rectus, inferior rectus, inferior oblique): innervated by oculomotor (CN III)  constriction of pupil - GVE  Holding eyelid open – GSE

What are some problems involving the cranial nerve 3?

 Ptosis: eyelid drooping  Strabismus: cross eyed:  tumor, stroke, brain injury can all impact eye movement  Diplopia: double vision

What is the 4th cranial nerve? where is it located? what is its functions?

Trochlear: Trochlear nerve in midbrain.  Superior oblique: moves eyes down innervated by (CN IV)  Smallest nerve (number of axons)  Greatest intracranial length  Moving the eyes downward  only cranial nerve that exits from dorsal aspect of brainstem

What is the 5th cranial nerve? where is it located? what are its branches? what type of fiber are each of these?

Trigeminal: At level of pons, opthalamic and maxillary branches are sensory, mandibular is sensory and motor. Biggest nerve among cranial nerves, general nerve, efferent and afferent functions (GVE< GVA< GSA< GSE) B1: opthalamic: provides sensory information for forehead, eyelids, nose B2: maxillary: sensory, provides for nose, lower eye, upper jaw/teeth B3: mandibular sensory and motor, muscles of chewing (masseter, temporalis, anterior belly of digastricus, pterygoid branch (one of them)), controls tongue area, opening jaw. Foramen that it passes through (middle fossa): superior (orbital fissure) foramen rodunume, foramen ovale (mandibular)

what are the three foramen that the branches pass through? which is for which branch?

Foramen that it passes through (middle fossa): superior orbital fissure (opthalamic), foramen rodunume(maxillary), foramen ovale (mandibular)

Function of the trigeminal nerve

 GSA: touch, pain, temp. and vibration for face, mouth, ant. 2/3 of tongue  GVE: Chewing muscles

Problems with trigeminal nerve:

loss of above sensations, and difficulty chewing

which nerve controls the anterior 2/3 of the tongue in terms of sensory information?

Cranial Nerve V

The anterior 2/3 for taste is controlled by____

cranial nerve VII

Posterior 1/3 of tongue for sensory information AND taste is controlled by ______

the glossopharyngeal nerve

what type of nerve is the abducens? what does it control? problems that may occur?

motor nerve GSE nerve Controls movement of single muscle  lateral rectus muscle of eye.  Problem(s) = eye rotates in (strabismus) and diplopia

what type of fibers make up the facial nerve?

Facial: Mostly motor but some sensory nerves for taste. Parasympathetic proprioceptive sensors for tears. GVE: parasympathetic innervation to lacrimal, submandibular and sublingual glands. SVA: taste anterior 2/3 of tongue

where is the nuclei for the facial nerve located?

Nuclei located in pons, fibers exit at pontomedullary junction (between pons and medulla) Innervating facial muscles (speech production and swallowing)

What is the function of the facial nerve?

 muscles of facial expression  Taste anterior two-thirds of tongue

Problems that occur with facial nerve

 Bell’s Palsy  Problem(s) = Facial paralysis/paresis; taste loss Consequences for speech: weak articulation Consequences for swallowing: drooling

what is the 8th cranial nerve? location? function?

 Sound and equilibrium  Vestibular (SSA)  Cochlear  Hearing and balance  Tinnitus or ringing  Located from pons and medulla

what are the two groups of fibers that the vestibulocochlear nerve is broken up into?

 2 groups of fibers: cochlear and vestibular

What two nerves go through internal auditory meatus?

CN VII and CN VIII go through this foramen.

General pathways of cochlear fibers

General pathway of cochlear fibers: axons of neurons (bipolar) in cochlea exit as fibers of nerve going to medulla, pass through pons, make synapses in superior olivary complex, and midbrain inferior colliculus, go to thalamus (MGB medial geniculate body) to auditory cortex (temporal lobe).

Function of cranial nerve IX

 receives sensory from (GSA)  posterior one-third of tongue  Tonsils  Pharynx  middle ear  supplies parasympathetic fibers to  Gag reflex (GVA)  stylopharyngeus muscle (Elevating larynx)  GSE and GVE nerve (sensory and motor fibers)

what two nerves trigger the gag reflex?

IX and X

the jugular foramen houses what two nerves?

Jugular foramen: IX and X

Branches of the X cranial nerve

Pharyngeal branches: • Superior, middle and inferior pharyngeal constrictors • Levator veli palatini Laryngeal branches  Muscles of the larynx  Sensory above and below larynx  Starts at sides of medulla, sensory and motor fibers,  If pharyngeal branch is affected they will have issues swallowing  levator veli palatini (elevates soft palate) to block VP port so that we don’t have nasal speech in sounds that don’t need to be. For nasal sounds soft palate needs to be lowered.  Larynx branch  Cricoarytenoid, thyrovocalis and thyromuscularis  Extrinsic muscles: up and down movement mylohyoid, diagstrics, geniohyoid  Intrinsic muscles: moving cartilages of larynx,

Functions of Cranial Nerve X and issues

 Issues: paralysis of vocal folds: breathiness, cant breathe, cant change pitch (cricothyroid)  Sensory above and below vocal folds supraglottic and subglottic: if this doesn’t work properly you would have silent aspiration (can cause pneumonia)  VP closure, voice production, swallowing (pharyngeal phase)  Gag reflex  pain from the pharynx, larynx, trachea, esophagus, abdominal muscles

Accessory Nerve Function, Location, Type of Fiber

 ACCESSORY  provides motor innervation  sternocleidomastoid muscle  upper part of trapezius muscle  GSE: motor  Nuclei located in medulla, innervation for sternocleidomastoid and trapezius muscle (accessory in respiration especially expiration).  Jugular foramen

Hypoglossal Nerve, fiber type, issues, what is the exception of tongue muscles that this innervates?

Hypoglossal: Motor nerve GSE intrinsic and extrinsic of tongue Issues: articulation of lingual sounds, formation of bolus, transition of bolus during swallowing bilabial, labial not affected Hypoglossal canal Idea about someone who has tumor on hypoglossal nerve, what speech sounds are involved? What are not? Not: P,b, m,n,ng, f,v  motor fibers to all muscles of tongue except palatoglossus muscle (Vagus nerve)

what is the limbic system known for?

Limbic system = the brain’s emotional system

What is the acronym that helps you remember the functions of the limbic system

• H = Homeostasis • O = Olfaction: (not involved is the thalamus) • M = Memory • E = Emotion

Cingulate Cortex: also known as, what is it? where is it?

• Also known as cingulate gyrus • Arch-shaped band of cortical tissue between the corpus callosum and the lobes of the brain • Functionally, helps identify negative emotions

James Papez (1883–1958) proposed the Papez circuit, made up of the following structures:

• Limbic Lobe (Cingulate cortex +Uncus+ parahippocampal gyrus) • Hippocampus (memory) • Hypothalamus • Amygdale • Anterior Thalamic Nuclei • Brainstem (reticular formation)

Label the above on this diagram: Limbic Lobe (Cingulate cortex +Uncus+ parahippocampal gyrus) • Hippocampus (memory) • Hypothalamus • Amygdale • Anterior Thalamic Nuclei • Brainstem (reticular formation)

Limbic Lobe (Cingulate cortex +Uncus+ parahippocampal gyrus) • Hippocampus (memory) • Hypothalamus • Amygdale • Anterior Thalamic Nuclei • Brainstem (reticular formation)

Limbic Lobe (Cingulate cortex +Uncus+ parahippocampal gyrus) • Hippocampus (memory) • Hypothalamus • Amygdale • Anterior Thalamic Nuclei • Brainstem (reticular formation)

Label the Papez Circuit

Amygdala: what is it? Where is it?

• What is it? – Nuclear mass • Where is it? – Buried in the white matter of the temporal lobe, in front of the hippocampus

what part of the limbic system in our ability to preserve ourselves and respond to danger

amygdala

• Specific behaviors the amygdala regulates:

Feeding and drinking – Fighting – Mating – Providing maternal care – Responding to physical/environmental stress – The brain’s shortcut for fear and self-preservation

Damage to the amygdala can cause the following:

– Flattened emotions – Abnormal fear – Aggression – Anxiety • Dysfunction may be connected to depression, anxiety, and posttraumatic stress disorder (PTSD)

Damage to the cingulate cortex results in:

– Decreased social behavior – Reduced time spent with others – Decreased vocalizations

Limbic connection

• There are numerous connections between the prefrontal cortex and the limbic system. • Cingulate cortex does appear to play a role in cognition. – Attention – Theory of Mind (ToM): the ability to understand that I have a mind, you have a mind, and that our minds are different from one another

Hypothalamus: what is it? where is it? what does it do?

Hypothalamus: • What is it? – A deep brain structure made up of a number of nuclei • Where is it? – Base of the fore brain – Just above the brainstem – Forms part of the walls of the 3rd ventricle • What does it do? – Linker : nervous system to endocrine system – Regulator : Circadian cycles

• Sexual response

• Temp, hunger, thirst, anger, and fatigue

What shape is the thalamus?

almond shape

WHAT GOES INTO THE THALAMUS?***

• Processing station in the center of the brain – All sensory systems (except olfaction) – Motor inputs from cerebellum and basal ganglia – Limbic inputs – Blood supply – Strokes lead to (Thalamic syndrome) – Damage leads to coma, excessive daytime sleepiness – Thalamic aphasia (Fluent, intact repetiotin) – Sensory processing difficulties

Function of Brainstem

Brainstem: recticular formation • Receives hypothalamic and cortical output – separate descending projections that run parallel to volitional motor system • Output to somatic and autonomic effector systems – cardiac, respiratory, bowels, bladder – Coordinates brain-body response

Match the Cranial Nerve and its Function A. innervating muscles of chewing B. levator veli palatini C. transverse muscles of the tongue

a. trigeminal b. vagus c. hypoglossal

Cranial Nerves ____ and ____ pass through the internal foramen

VII and VIII

which cranial nerve is not SA a. II b. I c. VIII d. V

Cranial Nerve V

What are the two branches of CN VIII

Vestibular and Cochlear

Which cranial nerve is responsible for mediating taste sensation to the posterior 1/3 of the tongue?

hypoglossal (CN IX)

. Which cranial nerve gives rise to the recurrent laryngeal nerve that innervates the larynx?

Vagus Nerve

What two (2) cranial nerves are involved with the “gag-reflex”?

X and XI

Which cranial nerve innervates motor functions to the intrinsic muscles of the tongue?

Hypoglossal (CN XII)

A lesion of CN-________ could result in deviation of the jaw to the same side of the lesion.

Trigeminal