Chapter 16: The Brain and Cranial Nerves

What are the 3 layers of the cerebellum?

-Molecular layer: where you find dendrites of purkinje cells -Purkinje layer: where you find cell bodies of purkinje cells -Granular layer: where you find axons of purkinje cells, and tightly packed small neurons

Where is the BBB absent?

1) Choroid plexus, has capillary endothelial ells and ependymal cells, but NO astrocytes 2) Hypothalamus, has receptors that need to sense the chemical content of our blood so it needs easy access to our blood content 3) Pituitary gland (ADH) and pineal gland (melatonin), because they need to release their hormones into the bloodstream

Made up of collagen fibers, these structures help to anchor the cerebral blood vessels to their place. Arachnoid mater has the presence of this, what is it called?

Arachnoid Trabecula

Extensions of the arachnoid mater and we have the CSF reaching the superior sagittal sinus and is the place where CSF gets back into the bloodstream.

Arachnoid granulations

Bundle of white matter and between primary and premotor cortex. Responsible for connecting areas of the cerebral cortex, some examples are the arcuate fibers and longitudinal fasiculus.

Association fibers

-Regulates substances between out blood and brain tissue. -It is made up capillary endothelial cells surrounded by astrocytes. -Allows nutrients to go in and nourish the brain tissue, nutrients like glucose and oxygen. -Allows CO2 and waste to get out of the brain tissue

Blood-brain barrier (BBB)

-Mesencephalon: processing of visual and auditory data, generating reflexive somatic motor responses, and maintains consciousness -Pons: relays sensory info to cerebellum and thalamus, and subconscious somatic and visceral motor centers -Medulla Oblongata: relays sensory information tot eh thalamus and other portions of the brainstem, autonomic centers regulate visceral function, also links the spinal cord and brain region

Brainstem

Pons can modulate the respiratory center because it deals with breathing patterns

Cardiac and respiratory centers

What does the fourth ventricle communicate with? Hint: it is underneath the fourth ventricle

Central canal of spinal cord

Frontal lobe and parietal lobe are separated

Central sulcus

-Posterior part -Coordinates complex motor patterns -Adjusts output of other somatic motor centers in brain and spinal cord

Cerebellum

The gray matter in the cerebellum is called ___________. The white mater in the cerebellum is called ___________.

Cerebellum cortex Arbor vitae

-Prevents contact of neural tissue with the surrounding bones; gives buoyancy to the CNS structures since it's inside it -Provides support of the brain -Transports nutrients to the CNS tissue -Transports waste away from the CNS

Cerebrospinal fluid

-Biggest area of our brain -Conscious thought processes, intellectual functions -Memory storage and processing -Conscious and subconscious regulation of skeletal muscle contractions

Cerebrum

Collection of neuronal cell bodies in the surface of the CNS

Cerebrum cortex

Inside of all four ventricles there is a vascularized membrane called _______, which are blood vessels surrounded by _________, type of glial cells responsible for producing the CSF at a constant rate and they take nutrients from the blood and turn it into CSF.

Choroid plexus Ependymal cells

CSF goes from the lateral to the third ventricle to the fourth ventricle, this direction is called?

Ciliated movements of the ependymal cells

If there was nothing between the cerebrum hemispheres, they wouldn't be able to communicate. So, there is a bundle of axons that decussate cross between the two hemispheres. The axons connecting the two cerebral hemispheres is called?

Corpus callosum

-Motor function; contract extra-ocular eye muscles, EXCEPT superior oblique, lateral rectus, and intrinsic muscles. -Helps us to move our upper eyelid and in changing the diameter of our pupil, and changes shape of the lens that gives us the focus.

Cranial Nerve III: Oculomotor Nerve

Motor function; controls the superior oblique muscle; passes through a ligament of trachea on its way to the insertion of the superior surface of the eye

Cranial Nerve IV: Trochlear Nerve

-Sensory AND motor functions -Sensory: taste from posterior third of the tongue, baroreceptors and chemoreceptors -Motor:swallowing (pharyngeal muscles and parotid gland)

Cranial Nerve IX: Glossopharyngeal Nerve

-Sensory AND motor function -Divides into 3 branches: ophthalmic branch, maxillary branch, and mandibular branch -Associated with the sensation from the entire face including all the teeth and voluntary control of the chewing muscles, such as masseter -Ophthalmic branch and maxillary branch ONLY have sensory function and the mandibular branch has sensory AND motor functions, so the mandibular branch innervates the muscles of mastication; maxillary branch lets you have sensation on you upper teeth and mandibular branch lets you have sensation on your lower teeth

Cranial Nerve V: Trigeminal Nerve

Motor function; controls lateral rectus of your eyes

Cranial Nerve VI: Abducens Nerve

Sensory AND motor function -Sensory: taste from anterior two-thirds of tongue -Motor: controls muscles of the face, lacrimal gland, submandibular gland and sublingual glands

Cranial Nerve VII: Facial Nerve

-Sensory; balance and hearing -Consists of the vestibular never and cochlear nerve -Vestibular nerve: axons travel to vestibular nuclei of the medulla oblongata -Cochlear nerve: axons synapse in the cochlear nuclei of the medulla oblongata

Cranial Nerve VIII: Vestibulocochlear Nerve

-Sensory and motor functions; goes to different regions of our body including the thoracic and abdominal cavities; innervates the respiratory, cardiovascular and digestive organs. -Longest nerve out of ALL the nerves

Cranial Nerve X: Vagus Nerve

-Motor function; controls the sternocleidomastoid, trapezius, palate, pharynx, and larynx muscles -Only nerve that has a cranial root and a spinal root, and when they converge it makes this nerve

Cranial Nerve XI: Accessory Nerve

Motor funciton; controls tongue movement

Cranial Nerve XII: Hypoglossal Nerve

Sensory function; smell

Cranial nerve I: Olfactory Nerve

-Sensory function, vision, responsible for carrying the visual information to specific parts of out brain. -Only nerve that comes together then splits again

Cranial nerve II: Optic Nerve

Anchors the brain and is a point of attachment in the inferior anterior aspect of the falx cerebri

Crista galli

Sella turcica has the pituitary gland sitting and what encases the sella turcica is the _________________, another fold of the dura mater, and lines the sella turcica and anchors the dura mater to the sphenoid bone.

Diaphragm sellae

Subdivided into the epithalamus, thalamus, and hypothalamus

Diencephalon

Above the mesencephalon we have the ________ and ______. Under the mesencephalon we have the ________ and ________.

Diencephalon and cerebrum Pons and medulla oblongata

Extensions of the dura mater that goes deep inside the brain. These folds subdivide the cranial cavity and they support and limit the brain movement.

Dura septum

When the layers of the dura mater separate, there is a blood filled space, which gets filled with venous blood and a majority of blood from our brain drains into and then the jugular vein drains the blood out of our brain, gets blood supply from this space, which is called?

Dural venous sinus

Contains the pineal gland which produces melatonin

Epithalamus

Folds on the cerebellum

Folia of the cerebellum

Located between the pons and cerebellum

Fourth ventricle

Conscience control of skeletal muscles and related to trouble-solving, reasoning and planning

Frontal lobe

The dark part of the cerebrum that has neuronal cell bodies

Gray matter

When you pull back the temporal lobe you have an area called insult, which is where you can find ___________, the perception of taste

Gustatory cortex

Overproduction of CSF or obstruction at some point within the ventricular system of problems with the CSF absorption is called ________. Babies that are born with this condition is because the skull bones are not fused yet so there is an increased pressure and causes the head to be very large. In adults, because of the rigidity if the skull, it keeps pressure and could lead to brain damage. The treatment is to drain CSF from a ventricle

Hydrocephalus

-Known as the center of homeostasis -Temperature control center -Involved in emotions, behavioral drives (thirst), and body temperature. If we are hot, we sweat and if we are cold, we shiver -Main visceral center -Connects to the pituitary gland (ADH), and it controls the release of hormones -Has an area called infundibulum, which connects the pituitary gland to this particular area of brain

Hypothalamus

Between the left and right thalamus, we have the ________________ and it has the third ventricle and the two thalami surrounding it.

Inter thalamic adhesion

How does the lateral ventricles and the third ventricle communicate? How does the third ventricle and the fourth ventricle communicate?

Interventricular foramen Cerebral aqueduct

Separating the temporal lobe from all the other lobes

Lateral sulcus

Ventricles 1 and 2 and located in the cerebrum hemispheres. Extend from the anterior horn located in the frontal lobe of the posterior horn located in the occipital lobe and the inferior horn located in the temporal lobe. Most are located within the parental lobe.

Lateral ventricles

Deep depression that separates the left and right hemispheres of cerebrum

Longitudinal fissure

When CSF reaches the fourth ventricle it can leave the ventricular system through apertures found at the roof of the fourth ventricle, they are openings that communicate with the subarachnoid space in the brain and in the spinal cord.

Median and lateral apertures

Located under the pons and is the part that connects the brain and spinal cord. Also is a relay station between the spinal cord and the thalamus. has the vagus nerve leaving this area of the brain, so it is related to the autonomic control of organs in the thoracic and abdominal cavities.

Medulla oblongata

inflammation of the meninges, and happens when there is no reabsorption of the CSF. Since there is no communication between where the CSF is made and where it is absorbed, it can raise the intercranial pressure and can be fatal.

Meningitis

Moves our eyes because almost all extrinsic eye muscles are inverted by cranial nerves that leave this area. Also, plays a role in processing sight, sound, and associated reflex, so when you hear a loud noise, you jump

Mescencaphalon

Related to vision, has a visual cortex.

Occipital lobe

Where the optic nerves cross, and is exactly on top of the superior part of the pituitary gland. The fibers of each nerve they cross the opposite side of the brain which is important because thats what allows our visual sensory information from each eye to be received on both sides of the brain simultaneously.

Optic Chiasm

Related to sensations

Parietal lobe

Between the parietal lobe and occipital lobe

Parieto-occipital sulcus

Underneath the arachnoid mater and is the softest of the meninges and nourishes the brain

Pia mater

Relay station between cerebellum and cerebrum. Plays a role with the cerebellum in coordinating skeletal muscle activity. Also, has a role in our breathing pattern because it has centers that regulate the activity of the respiratory reflux center in the medulla oblongata

Pons

Where the thinking, trouble solving, concentration, behavior, personality, morality, and judgment happens. If something goes wrong in this area, we can have different psychological disorders.

Prefrontal cortex

Anterior to the primary motor cortex, related to planning motor movements, like when you think about grabbing a pen to write

Premotor cortex

In front of the central sulcus we have the __________, the part of the brain that sends the nerve impulses down the spinal cord toward the muscle, when you was to control any specific movements. You will find pyramidal cells.

Primary motor cortex

Located in the parietal lobe, an area where we feel sensations like skin, muscles and joints

Primary somatosensory cortex

When groups of axons link the cerebrum with other regions of the brain spinal cord

Projection fibers

Neurons responsible for our coordinated movements

Purkinje cells

What is the order of the layers that protect the brain?

Scalp to epicranial aponeurosis to periosteum of cranium to cranium to cranial meninges (dura mater, arachnoid mater and pia mater)

Lateral ventricles do not communicate with each other, there is no direct communication between the two lateral ventricles, they are separated by a partition called?

Septum pellucidum

Allows you to understand the texture in the size and shape of something you are holding in your hands

Somatosensory association area

The space between the arachnoid mater and pia mater, is a true space, and is where we find the CSF flowing through it. If there is not enough CSF then we can get a headache.

Subarachnoid space

The sinus between the right and left cerebral hemispheres in the superior side

Superior sagittal sinus

Has an auditory cortex and an olfactory cortex. Related to hearing and smell

Temporal lobe

-Has a right and left thalamus separated by a fluid filled space called third ventricle -Largest uncle in CNS because it has a group of neuronal cell bodies -Relays information to the cerebrum/ processes sensory information

Thalamus

Located in the diencephalon

Third ventricle

Capillary endothelial cells are attached to each other by _____, which block the passage of material between the cells.

Tight junctions

What is the point of having gyri in the cerebrum?

To increase the surface area in the cerebrum

Deep depression that separates the cerebrum and cerebellum

Transverse cerebral fissure

Fluid filled cavities are called ventricles. Inside the ventricles, we have CSF. There are four ventricles, and together they form the?

Ventricular system of the brain

Separates the right and left hemispheres of the cerebellum

Vermis

When you associate a face to a person

Visual association area

Under the gray matter and is composed of myelinated axons

White matter

Arachnoid mater

acts as a roof to protect cranial blood vessels that supply the brain

If the dura mater fold is located between the right and left cerebellum hemispheres we call it?

falx cerebelli

If dura mater fold is located between the right and left hemispheres of the cerebrum we call it?

falx cerebri

What are the layers of the dura mater?

periosteal layer (attached to inner surface of the skull) and meningeal layer (true layer the covers the brain and extends to the vertebral canal)

The anterior lobe and posterior lobe of the cerebellum is separated by?

primary fissure

Subdural space

space between the arachnoid and dura mater layers of the meninges; a potential space that can be filled with fluid is necessary. An example is the subdural hematoma

If the dura mater folds are located along the transverse cerebral fissure we call it?

tentorium cerebelli

Dura mater

toughest and outermost layer of the meninges