Lab 12: Brain & Cranial Nerves (Vocab)

List the 4 major sections that the brain is composed of

1. cerebrum

2. dincephalon → thalamus, hypothalamus, epithalamus

3. cerebellum

4. brain stem - midbrain, medulla oblongata, pons

What are the names of the 3 cranial meninges

1. Dura mater

2. Arachnoid mater

3. Pia mater

What are the venous sinuses?

drain blood from the brain to the internal jugular veins

What is the falx cerebri?

extension of the dura mater that separates the 2 cerebral hemispheres & attaches to the crista galli of the ethmoid bone

What are arachnoid granulations (villi)?

the arachnoid mater penetrates through the dura mater into the venous sinuses w/ extensions of tissue called arachnoid granulations — these reabsorb CSF into the blood

List the 4 lobes of the cerebral hemispheres

1. frontal

2. parietal

3. occipital

4. temporal

The surface of the cerebrum has many convultions in the tissue; deep grooves called (1)___ & shallow grooves called (2)___ (singular: (3)___). On the either side of a (2) is a bulge of tissue called a (4)___ (plural: (5)___)

1. Fissures

2. Sulci

3. Sulcus

4. Gyrus

5. Gyri

A prominent sulcus called the (1)___ forms a key landmark on the brain as it separates the frontal & parietal lobes of the cerebrum. The gyrus anterior to the (1) is called the (2)___ and the gyrus located posterior to the (1) is called the (3)___. The right & left hemispheres are separated from each other by the (4)___

1. central cerebral sulcus

2. precentral gyrus

3. postcentral gyrus

4. longitudinal cerebral fissure

Name the sulci that separate the cerebral lobes

• parieto-occipital sulcus

• lateral cerebral sulcus (separates frontal from temporal lobe)

What separates the cerebrum from the cerebellum?

transverse cerebral fissure

What is the arbor vitae?

cerebellar white matter; structure resembles a tree

What is the interthalamic adhesion (intermediate mass)?

a bridge of gray matter that joins the right & left halves of the thalamus in ~70% of brains; center dot inside thalamus

What is the corpus callosum?

white structure inferior to cerebrum; contains axons that connect right & left cerebral hemisphere

Constrast the pineal gland and pituitary gland

pineal gland (middle of the brain) → regulates sleep-wake cycles by secreting melatonin

pituitary gland (base of the brain) → “master gland” that controls growth, metabolism, & other hormones

What is the infundibular stalk?

a ventral down growth of tissue that connects the pituitary gland to the hypothalamus

List the hormones secreted by the pituitary gland

1. Growth hormone (GH)

2. Thyroid-stimualting hormone (TSH)

3. Follicle-stimulating hormone (FSH)

4. Luteinizing hormone (LH)

5. Prolactin (PRL)

6. Adrenocorticotropic hormone (ACTH)

7. Melanocyte-stimulating hormone (MSH)

What are the functions of melatonin

regulates cicadian rhythms; induces sleep, serves as an antioxidant, ihibits reproductive functions in certain animals

List the function of the frontal lobe

• voluntary muscle movements (motor cortex)

• higher intellectual processes (problem solving, language, concentration, planning, etc.)

List the functions of the temporal lobes

• hearing & smelling (olfaction)

• memory of complex sensory forms (music, visual patterns, etc.)

List the functions of the parietal lobes

• perception of touch, pain, pressure, & heat in skin

• understanding & formulation of speech

List the functions of the occipital lobes

• vision

• blend of visual & nonvisual sensory experiences

Within the brain are cavities called ___ that are filled with ___

ventricles; CSF

What are the 2 lateral ventricles separated by anteriorly?

septum pellucidum → thin membrane

Where is the 3rd Ventricle found?

thalamus

Where is the 4th Ventricle found?

between the brainstem & cerebellum

What type of neuroglial cell produces CSF?

Ependymal Cells

What are choroid plexuses?

networks of blood capillaries within each of the ventricles; lined by ependymal cells which produce CSF

What are the 3 functions of CSF?

1. mechanical protection → shock-absorbing; protects the brain & spinal cord from physical injuries; allows bain to float

2. chemical protection → provides optimal chemical environment for accurate neuron signaling

3. circulation → minor exchange of nutrients & waste products between blood & adjacent tissue

What is the aqeuduct of the midbrain ?(cerebral aqueduct)

narrow channel in midbran connecting the 3rd ventricle to the 4th ventricle, facilitating flow of CSF

What is the central canal?

(continuous w/ the 4th ventricle) small space in center of gray commissure; extends entire length of spinal cord and is filled with CSF

What is the interventricular foramen?

2 narrow, oval openings that CSF from the lateral ventricles flows out through

The brain does not have the ability to store ___

glucose

Oxygen & glucose must be brought to the brain via the ___ & ___

internal carotids; vertebral arteries

What is the Circle of Willis? List its 2 functions

cerebral arterial circle

• group of blood vessels that creates redundancies (duplicates/backup) in cerebral blood to ensure that if one side of the circle is damaged, the other side can compensate & maintain adequate blood supply to brain tissue

• equalizes blood pressure to the brain

Venous blood circulates through the ___ ___ that are found between the 2 layers of the ____ ___ & leaves the brain via the ____ ____

venous sinuses; dura mater; jugular veins

List the blood vessels of the cerebral arterial circle (Circle of Willis)

1. Anterior Cerebral

2. Anterior Communicating

3. Posterior Communicating

4. Posterior Cerebral

5. Middle Cerebral

6. Internal Carotid

7. Basilar

8. Vertebral

Explain the diff. between a gyrus and a sulcus

gyrus → elevated ridge of the cerebral cortex

• precentral gyrus → frontal lobe; primary motor cortex

• postcentral gyrus → parietal lobe; primary somatosensory cortex

sulcus:

• cerebral sulcus → grooves that separate cerebral gyrus

• interlobar sulcus → grooves that separate the lobes of the cerebrum

  • e.g. parieto-occipital sulcus, central cerebral sulcus, lateral cerebral sulcus

Explain the difference between a sulcus and a fissure

sulcus:

• cerebral sulcus → grooves that separate cerebral gyrus

• interlobar sulcus → grooves that separate the lobes of the cerebrum

  • e.g. parieto-occipital sulcus, central cerebral sulcus, lateral cerebral sulcus

fissure → grooves that separate the parts of the brain

• e.g. longitudinal cerebral fissure

List two tasks that demonstrate the function of the cerebellum. Exactly how do these demonstrate the function?

1. w/o looking at feet, walk in a straight line placing the heel of one food directly in from of the toe of the other foot

2. close eyes and stand erect w/ feet together for 1 min

cerebellum → coordinates voluntary movements, balance, coordination, posture, muscle tone

List 2 cerebral function tests

1. Category Clustering → read through a list of words then write down as many words as you can remember

2. Visual VS Verbal Coding → Look at words VS images sequentially and write down as many as you can remember

List the 12 cranial nerves and indicate if sensory, motor, or both

1. Olfactory I S

2. Optic II S

3. Oculomotor III M

4. Trochlear IV M

5. Trigeminal V B

6. Abducens VI M

7. Facial VII B

8. Vestibulocochlear VIII S

9. Glossopharyngeal IX B

10. Vagus X B

11. Accessory XI M

12. Hypoglossal XII M

What are the body part(s) and effect of the olfactory bulbs/tracts?

body part:

• olfactory epithelium

effect:

• convey impulses relate to smell

What is the body part(s) and effect of the optic nerve?

body part:

• retina

effect:

• vision

What is the body part(s) and effect of the oculomotor nerve?

body parts:

1. inferior rectus

2. medial rectus

3. superior rectus

4. inferior olbique

5. ciliary muscle

6. circular muscle of iris

7. upper eyelid muscle

effect:

1. moves eye superiorly & medially; rotates medially

2. moves eyes medially

3. moves eyes inferiorly and medially; rotates medially

4. moves eyes superiorlu & laterally, rotates eyes laterally

What is the body part(s) and effect of the trochlear nerve?

body part:

• superior oblique muscle

effect:

• moves eyes inferiorly & laterally; rotates medially

What is the body part(s) and effect of the trigeminal nerve?

body parts:

• Masseter

• Temporalis

Effect:

• clench teeth (onto tounge depressor)

• clench jaw (temporal region)

What is the body part(s) and effect of the abducens nerve?

body parts:

• lateral rectus muscle

effect:

• moves eyes laterally (abduction)

What is the body part(s) and effect of the facial nerve?

body parts:

• taste buds (anterior 2/3 of tongue)

• frontalis

• orbicularis oris

effect:

• wrinkle forehead; raise eyebrows

• inflate cheeks, pucker mouth

• saliva & tear production; taste

What is the body part(s) and effect of the vestibulocochlear nerve?

body parts:

• cochlear branch → cochlea (& auricles)

• vestibular branch → vestibule

effect:

• hearing

• balance; posture

What is the body part(s) and effect of the glossopharyngeal nerve?

body parts:

• taste buds (posterior 1/3 of tongue)

• throat muscles

effect:

• swallowing; gag reflex

• saliva production

What is the body part(s) and effect of the Vagus nerve?

body parts:

• throat muscles

effect:

• swallowing; “Ahhh” test

• speech

What is the body part(s) and effect of the Accessory nerve?

body parts:

• Trapezius muscles

• Sternocleidomastoid muscle

effect:

• shrugging shoulders

• rotating head

What is the body part(s) and effect of the Hypoglossal nerve?

body part:

• muscles of the tongue

effect:

• movement of tongue during speech & swallowing

Identify the test for the olfactory I nerve

1. eyes closed, one nostril pugged

2. identify garlic powder or ground coffee smell one at a time

olfactory epithelium

Identify the test for the optic II nerve

1. Read paragraph for one minute

2. Count # of words read

Retina

Identify the tests for the oculomotor III neve

A:

1. cover one eye with hand

2. shine pen light in other eye and note change in pupil diameter

muscles of the iris

B:

1. open both eyes as wide as possible

2. note any eyelid drooping

upper eyelid muscles

Identify the test for the trochlear & abducens muscles

A: Trochlear & Abducens

1. Partner hold pencil in front of subject & slowly moves it up,down, medially, laterally, upper laterally, lower laterally

2. Subejct follows pencil w/o moving head

lateral rectus, superior oblique

B: Abducens

1. Cover left eye

2. Look laterally w/ right eye

3. Switch eyes & repeat

lateral rectus

Identify the test for the trigeminal nerve

A: Masseter

1. clench teeth on tongue depressore while partner tries to pull it out

B: Temporalis

1. partner holds on hand firmly under chin

2. subject tries to open mouth

Identify the test for the facial nerve

A: frontalis & orbicularis oris

1. smile & show teeth

2. inflate cheeks

3. wrinkly forehead

4. raise 1 or both eyebrows

B: salivary glands & taste buds of 2/3 anterior tongue

1. dip cotton swab in sweet liquid & swab front of tongue

Identify the test for the vestibulocochlear nerve

A: cochlear branch (cochlea & auricles)

1. sit w/ eyes closed

2. partner holds ticking clock 1m from right then left ear

3. is sound heard from both ears & can u determine the direction

B: vestibular branch:

1. stand w/ feet together and eyes closed; maintain balance

Identify the test for the glossopharyngeal & vagus nerves

1. open mouth and carefully touch uvula w/ swab

2. open mouth & have partner hold tonguedown w/ tongue depressor; say “Ahhh”

throat muscles

Identify the test for the accessory nerve

A: trapezius

1. sit & have partner push down o shoulders

2. try to raise shoulders

B: sternocleidomastoid

1. partner hold sides of head

2. try to rotate head

Identify the test for the hypoglossal nerve

1. stick tongue out then retract tongue

2. note any deviation from midline

tongue muscles