lab 12

what are the 3 cranial meninges?

the cranial meninges are continuous with with spinal meninges

• pia mater

• arachnois mater

• dura mater

how many layers does the dura mater contain?

2 layers of the dura mater that are fused everywhere except at the dural venous sinus

what is the function of the meninges

protects the brain and spinal cord, contains CSF

dura mater function

outter most meningeal layer, 2 layers, extensions of the dura mater forms the flax cerebi which separates the two cerebral hemispheres, contains CSF

arachnoid mater function

middle meningeal layer that contains CSF in the subarachnoid space, which cushions and protects the brain and spinal cord

pia mater

inner most meningeal layer that adheres directly to the brain and spinal cord, it protects the brain and spinal cord

flax cerebi function

an extension of the dura mater that separates the two cerebral hemispheres

arachnoid granulations

extensions of the arachnoid mater that extend through the dural venous sinus to absorb CSF into the blood

subarachnoid space

located between he arachnoid mater and pia mater, contains CSF that functions as a shock absorber

venous sinus

large space of the dura mater that drains blood out of the brain and into the internal jugular veins, recieves CSF from the arachnoid granulations

cerebrum function

allows for higher level of thinking and coordinates voluntary movements, memories, and interpretation of sensory information

cerebral hemispheres desc/ fucntion

separates into the L and R cerebral hemispheres,

• left hemisphere= language

• right hemisphere = visual + spatial skill

frontal lobe function

(contains primary motor area, brocas speech area, prefrontal cortex)

anterior to the central sulcus

• controls voluntary movements

• production of speech

• decision making + personality

parietal lobe

(contains the primary somatosensory area)

posterior to the central sulcus

• receives and interprates somatosensory information (pin, touch, temp, propioreception)

temporal lobe

(contains the primary auditory area, auditory association area + primary olfactory area)

• receives and interpreation auditory information, as well aas olfactory information

occipital lobe

(contains the primary visual area, visual association area)

• receives and interprets visual information

insula function

(contains the primary gustatory area)

• receives and interprets taste information

central cerebral sulcus function

separates the frontal and parietal lobes

lateral cerebral sulcus function

separates the frontal and temporal lobes

parieto-occipital sulcus function

separates the parietal and occipital lobes

precentral gyrus function

anterior to the central sulcus, contains the primary motor area which controls the voluntary contraction of skeletal muscle on the opposite side of the body

post central gyrus

posterior to the central sulcus, contains the primary somatosensory area which is involved with touch, pain, temp, and propioreception

longitudinal fissure

separates the two cerebral hemispheres

transverse fissure

separates the cerebellum from the cerebrum

cerebral white matter

composed of myelinated axons that propagate nerve impulses to different regions of the brain

cerebral cortex

composed of grey matter, contains the motor, sensory and association areas of the brain, which is responsible for voluntary movements and processing information

what is arbor vitae? what is it’s function

it is cerebellar white matter that resembles a tree

• carries signals within the cerebellum to coordinate movements, balance + posture

cerebellum function

evaluates how well movements that are being iniated by the motor areas of the cerebrum are actually being carried out

pituitary gland

a pea sized endocrine gland that secretes hormones involved in growth, reproduction and metabolism, as well as the activity of other endocrine glands

infundibular stalk function

connects the pituitary gland to the thalamus, and allows for communication + the transportation of hormones between the two structures

midbrain function

aka: mesencephalon

extends from the pons to the diencephalon

• contains sensory and motor tracts involved with visual and auditory reflexes

pons function

located superior to the medulla oblongata

• contains nuclei and tracts

• known as a bridge because it connects regions of the brain together via tratcs

• plays a role in breathing, contains the pontine respiratory group

medulla oblongata function

continuous with the spinal cord

• contains sensory tracts + motor tracts and nuclei

• contains nuclei that regulates the cerebellum

• contains vital centers that are involved with force and rate of heart contraction, blood vessel diamter, breathing rate, as well as reflexes such as coughing, sneezing and vomiting

spinal cord function

transmits sensory and motor information between the CNS + PNS, serves as a reflex center

corpus callosum function

a band composed of white mater that contains axons that connect the left and right cerebral hemispheres

thalamus function

contains the third ventricle

• known as a relay station, receives sensory information (except olfactory infromation), filters it, then sends it to other parts of the brain such as the primary centres of the cerebral cortex

interthalamic adhesion function

a band of grey matter that connects the two halves of the thalami across the third ventricle

hypothalamus function

known as one of the major regulators of homeostasis

• regulates body temperature, works with the limbic system to regulate emotional behaviours, produces hormones such as oxytocin and antidiuretic hormone, and controls the ANS (cardiac + smooth muscle + secretion from glands)

epithalamus function

superior to the thalamus, contains the pineal gland and habenular nuclei which is involved with sleep cycles and influences emotional and behavioural processes

pineal gland function

an endocrine gland that produces the hormone melatonin during darkness which influences sleep cycle

what type of neuroglial cell produces CSF

ependymal cells

what are the 3 functions of CSF

#1: mechanical function

• absorbs shock and protects the delicate tissues of the brain and spinal cord from jolts

#2: chemical function

• provides an optimal environment for neuronal signalling

#3: circulation

• fluid serves a medium for the exchnage of waste products and nutrients between the blood and the nervous tissue

briefly describe the flow of CSF

lateral ventricles —> interventricular formina —> third ventricle —> aqueduct of the midbrain —> fourth ventricle —> subarachnoid space + central canal of the spinal cord

lateral ventricles

2 ventricles one located in each cerebral hemisphere, contain CSF

septum pelucidum

seprarates the two lateral ventricles

third ventricle

located between the two hlaves of the thalamus, contains and circulates CSF

aqueduct of the midbrain

connects the third anf fourth ventricles, allowing for the flow of CSF

interventricular foramen

connects the lateral ventricles to the third ventricle, allows for the flow of CSF

choroid plexuses

blood capillaries covered in ependymal cells that are found in the ventricles of the brain that produce CSF

central canal

carries and circulates CSF through the center of the spinal cord

what structures form the circle of willis

the circle of willis is formed by the union of the internal carotid arteries and the vertebral arteries, which connect to the cerebral arterial circle, aka: the circle of willis

internal carotid artery function

ascends from the common carotid artery, supplies blood to the anterior region of the brain

anterior cerebral artery function

a branch of the internal carotid artery, supplies blood to the medial surface of the frontal + partial lobes

anterior communicating artery function

connects the L + R anterior cerebral arteries, allowing for collateral blood flow

vertebral artery function

ascends through the brain stem, forms the basilar artery, supplies blood to the brain stem, cerebellum + posterior region of the brain

basilar artery function

formed by the union of the vertebral arteries, located at the base of the brain, supplies blood to the brain stem, cerebellum + posterior regions of the brain

posterior cerebral artery function

terminal branches of the basilar artery, supplies blood to the temporal + occipital lobes

posterior communicating artery function

connects the internal carotid artery and the posterior cerebral artery, allowing for collateral blood flow in the circle of willis

What is a choroid plexus and why are choroid plexuses important to the nervous system?

the choroid plexus are blood capillaries covered in eyedymal cells, which produce CSF. this is important because CSF has a vartiey of functions such as shock absorption, chemical function as well as a circulatuon fucntion

where are choroid plexuses found?

in the ventricles of the brain: lateral, third + fourth

gyrus vs sulcus

gyrus: raised bumps on the surface of the brain

sulcus: shallow grooves/ depressions found on either side of the gyrus

fissure vs sulcus

fissure = deep grooves between the gyri

sulcus = shallow grooves between the gryi

2 functions of the cerebral arterial circle

#1= provides a redundant blood flow to the brain so that if one side of the circle was damaged, the other side can still adequately supply blood to the brain tissue

#2= equalizes blood pressure to the brain

name 3 examples of the cerebellar experiments preformed in the lab

#1- abduct both arms and snap your fingers

#2- close your eyes and stand erect for 1 minute

#3- close you eyes and touch your nose with your index finger

Explain how these procedures demonstrate the function of the cerebellum

the cerebellum is responsible for evalutaing how well the movements bring intiated by the motor area of the cerebrum are actually being carried out

• on top of that the cerebrum is responsible for fine tuning voluntary and involuntary movements

cerebral function: explain the experiment

read through 30 words, then recall and write down as many words as you can remember

• recalled 11 words

cerebellar function: Did you notice any trends with regards to which terms you recalled more easily? If so, were they at the beginning of the list, the middle or the end? In which section of the list did you have the fewest correct responses?

yes there was a trend, words that were at tghe beginning were easier to recall, as well as words at the end. words that were in the middle of the list werer the hardest to recall.

Looking at your answers, can you see any patterns with respect to the way you ordered your responses? Do you see any categories or groups of words that are related to each other which are next to each other in your list of answers?

yes, my recalled words tended to be in related categories. these categories were often written together in my response, showing that i remebered words by grouping similar items rather than recalling individual words

While you were writing down your answers, were you aware that you were categorizing or grouping the terms?

yes i recognized that i tended to group similar words together when recalling them even if i was not intentionally trying to categorize them

cerebral experiment: : Visual versus Verbal Coding

Which column had more correct responses?

Was there any consistency between the responses of your partner and yourself?

the visual column had more correct responses

yes, there was a general consistency as my lab parter and i both recalled more anatomical images rather than terms

Visual versus Verbal Coding : what conclusions do you draw form this experiment?

#1 = the cerebrum is responsible for memory and information processing

#2 = information is more easily recalled if its visual rather than auditory

#3 = the brain uses visual coding more effectively than word - based encoding

what were the two cerebral experiments preformed?

#1- category clustering

• reading 30 terms, then recalling as many as possible

#2 - visual vs verbal coding

• looking at 30 anatomical images vs anatomical terms, then seeing how many images vs terms were recalled

CN I

• name

• sensory/motor/ mixed

• body part innervating/ arising from

• effect on body part

olfactory nerve

sensory

olfactory epithelium of the olfactory nerve

conveys impulses related to smell

CN II

• name

• sensory/motor/ mixed

• body part innervating/ arising from

• effect on body part

optic nerve

sensory

retina

connects with the retina to produce vision

CN III

• name

• sensory/motor/ mixed

oculomotor

motor

oculomotor nerve

• superior rectus function

moves eye superiorly and medially, rotates them medially

oculomotor nerve

• medial rectus function

moves eye medially

oculomotor nerve

• inferior rectus function

moves eye inferiorly and medially, rotataes them laterally

oculomotor nerve

• inferior oblique

moves eyes superiorly and laterally, rotates eyes laterally

oculomotor nerve

• ciliary muscle of the eye function.

adjuts the lens for near and far sighted vision

oculomotor nerve

• circular muscle of the eye of the iris function

contricts the pupil to control the amount of light that enters the eye

oculomotor nerve

• muscle of the upper eyelid function

elevates the upper eyelid to open the eye

CN IV

• name

• sensory/motor/ mixed

• body part innervating/ arising from

• effect on body part

trochlear

motor

superior oblique muscle

moves eye inferiorly and laterally, rotates them medially

CN V

• name

• sensory/motor/ mixed

• body part innervating/ arising from

• effect on body part

trigeminal

mixed

face, scalp and oral cavity, muscles of mastication

sensory = pain touch + temp for the face, scalp and oral cavity (teeth + anterior 2/3 of the tongue)

motor= muscles of mastication

CV VI

• name

• sensory/motor/ mixed

• body part innervating/ arising from

• effect on body part

abducens

motor

lateral rectus muscle

moves eye laterally (abduction)

CN VII

• name

• sensory/motor/ mixed

• body part innervating/ arising from

• effect on body part

facial nerve
mixed

muscles of facial expression, taste buds for the anterior 2/3 of the tongue, lacrimal, nasal and salivary glands

sensory = taste buds for the anterior 2/3 of the tongue

motor = muscles of facial expression, lacrimal, nasal and salivary glands

CN VIII

• name

• sensory/motor/ mixed

• body part innervating/ arising from

• effect on body part

vestibulocochlear

special sensory

inner ear

hearing and equilibrium (balacne and vertigo)

CN IX

• name

• sensory/motor/ mixed

• body part innervating/ arising from

• effect on body part

glossopharyngeal

mixed

posterior 1/3 of tongue, pharynx, tonsils, parotid salivary gland

taste buds for the posterior 1/3 of the tongue, involved with speech and swallowing, produces saliva

CN X

• name

• sensory/motor/ mixed

• body part innervating/ arising from

• effect on body part

vagus nerve

mixed

pharyx, larynx, heart and lungs

controls the muscles of the pharynx, larynx, heart rate and breathing

CN XI

• name

• sensory/motor/ mixed

• body part innervating/ arising from

• effect on body part

accessory nerve

motor

pectoral girdle, sternocledmatotoid

muscles of the pectoral gridle, allows for movement of the neck

CN XII

• name

• sensory/motor/ mixed

• body part innervating/ arising from

• effect on body part

hypoglossal

motor

muscles of the tongue

controls movement of the tongue during speech and swallowing