Bio 264 Unit 11.5

Meninges are found                               . 

associated only with the brain

associated only with the spinal cord

associated only with the brain and cranial nerves

associated with the CNS

covering peripheral nerves

associated with the CNS

Which of the following is true of cerebral spinal fluid?

It is found in and around the brain but not the spinal cord.

It is produced by the choroid plexus.

It is produced by the pineal gland.

It is found between the dura mater and the arachnoid mater.

It is produced by the choroid plexus.

Cerebrospinal fluid is produced by                              .

ependymal cells

Cerebral spinal fluid exits the fourth ventricle via the                             .

median aperature

Which of the following cranial nerves would have a function that does not affect eye movement?

Cranial Nerve 2 (CN II)

Cranial Nerve 4 (CN IV)

Cranial Nerve 6 (CN VI)

Cranial Nerve 3 (CN III)

Cranial Nerve 2 (CN II)

Which of the following is not a meningeal layer?

Dura mater

Pia mater

Subarachnoid mater

Arachnoid mater

Subarachnoid mater

The dura mater                               .

is subdivided into two layers

is the most inner layer

is the thinnest layer

is all of the above

is subdivided into two layers

The arachnoid mater                               .

is the most superficial and thickest layer

is the membrane bound very tightly to the surface of the brain

is a thin, wispy membrane

is none of the above

is a thin, wispy membrane

The pia mater                              .

is the most superficial and thickest layer

is the membrane bound very tightly to the surface of the brain

is a thin, wispy membrane

is none of the above

is the membrane bound very tightly to the surface of the brain

A hemorrhagic brain injury, characterized by bleeding outside the dura is termed                              .

an epidural bleed

A hemorrhagic brain injury, characterized by damage to small vessels within the brain and often associated with contusions, are known as                              .

an intracerebral bleed

A hemorrhagic brain injury, characterized by bleeding due to tears in the cortical veins or dural venous sinuses, is called                              .

subdural bleed

What cranial nerve would contain the most axons that carry information for the parasympathetic nervous system?

Cranial Nerve 10 (CN X)

Which is not a function of CSF?

It provides nutrients to the CNS tissues.

It provides a protective cushion around the brain and spinal cord.

It provides some nutritive factors to the PNS.

It protects the brain against the shock of rapid head movements.

None of the above; all are functions of CSF.

It provides some nutritive factors to the PNS.

The majority of the CSF is made in the                            

lateral ventricles

CSF                              .

is similar to plasma, but with most of the proteins removed

Cerebrospinal fluid is produced by the                             , circulates through the ventricles, and enters the subarachnoid space. The cerebrospinal fluid leaves the subarachnoid space through the                              .

chorid plexuses, arachnoid granulations

Hayes E. Daise has not been himself lately. He banged his head really hard and sustained an epidural bleed. Which of the following is likely true of Hayes?

His dura mater is likely contacting hemorrhaging blood

His pia mater has likely been compromised or torn

There will likely be no visible sign of damage on the scalp or skull

There will likely be bleeding into the deep brain tissues like the basal nuclei

All of the above are true

None of the above are true

His dura mater is likely contacting hemorrhaging blood

A patient tries to speak, but their words are garbled and hard to understand. What cranial nerve is most likely impaired?

The vestibulocochlear nerve

The trochlear nerve

The hypoglossal nerve

The abducens nerve

The hypoglossal nerve

Which of the following separates the two cerebral hemispheres?

Periosteal layer

Meningeal layer

Tentorium cerebelli

Falx cerebri

Falx cerebri

Describe the details of the layers of the meninges and how it protects the brain.  Can you name the layers from the outside in?

Skull bone, dura mater (thick, tough, and durable membrane composed of dense connective tissue), arachnoid mater, and pia mater

Define the periosteal layer and meningeal layer of the dura mater.

• Periosteal layer: Outer layer of dura mater, adheres to skull.

• Meningeal layer: Inner layer of dura mater, closer to brain and spinal cord.

§  In what areas of the brain do the following three structures of the meninges separate?

·       Falx cerebri

·       Tentorium cerebelli

·       Falx cerebelli

the falx cerebri separates the two cerebral hemispheres, the tentorium cerebelli separates the occipital lobes of the cerebrum from the cerebellum and the falx cerebelli separates the two cerebellar hemispheres

What is in the subarachnoid space beneath the arachnoid mater?

cerebrospinal fluid

What is the purpose or function of the arachnoid mater and subarachnoid space?

helps to cushion the central nervous system and fits like a loose sac over it

Why is it called the “arachnoid” mater?

These processes are very fine and look a bit like spider web fibers.

What is the purpose or function of the pia mater?

Protects and nourishes the brain and spinal cord.

How are the meninges of the brain different from the meninges of the spinal cord?

dura mater of spinal cord is one layer, rather than two in the brain. The dura mater has a space between the vertebra called the epidural space that helps act as a fatty cushion for the spinal cord

Describe where the cerebral spinal fluid is in relation to the meninges.

Cerebrospinal fluid is in the subarachnoid space, between the arachnoid mater and pia mater.

Discuss the function and production of cerebral spinal fluid.

it is the “blood” of the brain and spinal cord,

Function: Cushions, nourishes, and removes waste from the brain and spinal cord.

Production: Produced by the choroid plexus in the brain's ventricles.

Where is cerebral spinal fluid produced and from what type of cells?

It is produced in a structure called the choroid plexuses by ependymal cells

What are the five functions of CSF?

buoyancy (helps brain to suspend which reduces its weight), electrolyte and circulatory balance, protection, circulation, waste removal

What can happen if there is a decrease or leak of the CSF?

This can change the pressure and allow the brain to not be as buoyant, which squishes on nerves and causes a variety of symptoms. I

What is hydrocephalus?

the accumulation of CSF because of impaired flow or excessive production of CSF. This can also result in pressure changes and if it occurs in the fetus it can result in an enlarged head.

Epidural Bleed- location of bleed, common mechanisms of injury, and effect on brain

occur between the dura mater and the skull, they are very rapid because bleeding comes from arteries along the inside of the skull, it results in hematoma which strips the dura membrane off the skull as it expands, which causes bad headaches.

subdural bleed- location of bleed, common mechanisms of injury, and effect on brain

occur between the dura mater and the brain, they result from tears in the veins that cross the subdural space in response to a head injury, especially rotational or linear forces. Can come from shaken baby syndrome and severe whiplash, and people taking aspirin can get them more because of the inhibition of blood clotting.

subarachnoid bleed- location of bleed, common mechanisms of injury, and effect on brain

occur in the area between the arachnoid membrane and the pia mater that surrounds the brain, the bleeding may occur by spontaneous rupture of the arteries or as a result of a head injury. The most common symptom is called the thunderclap headache or one that develops immediately.

intracerebral bleed- location of bleed, common mechanisms of injury, and effect on brain

occur within the brain tissue itself and usually involve very small blood vessels, can be caused by trauma or spontaneous rupture, can cause stroke. Chances can increase with high blood pressure and diabetes.

Describe what is happening in each of the following clinical conditions, and how the proper function of that nerve can be tested: the Pupillary Light Reflex

The pupil will dilate in a dark environment to allow in more light and constrict in a light environment to restrict the amount of light entering the eye. When you shine a light into a patient's left eye the optic nerve should increase signals to the midbrain which will then cause the oculomotor nerve to stimulate the constrictor pupillae muscle to contract, thus constricting the pupil of the left eye.

Describe what is happening in each of the following clinical conditions, and how the proper function of that nerve can be tested: The Trigeminal Neuralgia (Tic Douloreux)

V1 (ophthalmic) supplies sensory innervation to the forehead down to the nose.

V2 (maxillary) supplies sensory innervation to the maxillary region inferior to the nose and superior to the lower jaw.

V3 (mandibular) supplies sensory innervation to the mandibular region or the lower jaw and anterior to the ear, as well as somatic motor innervation to the muscles involved in chewing

Trigeminal neuralgia involves intense episodic pain in any or all three facial areas supplied by CN V.

Describe what is happening in each of the following clinical conditions, and how the proper function of that nerve can be tested: Facial Palsy (Bell’s Palsy)

Bell's palsy is a condition that results in partial or complete facial paralysis on one side of the face, although some cases can manifest bilaterally. This is a result of a lesion of the Facial Nerve (CN VII), most likely due to inflammation

name the layers of the head in order

epidermis, bone, epidural space, dura mater- periosteal layer, dura mater- meningeal layer, subdural space, arachnoid layer, subarachnoid space (CSF), and the pia mater

simple epidural hemorrhages def

rupture arteries, usually from physical trauma, intense headaches

simple subdural hemorrhage def

venous bleed, slow leakage, shaken baby syndromes, whiplash

simple subarachnoid hemorrhages def

csf, thunderclap headaches

simple intracerebral hemorrhages def

strokes, damage to brain where it occurs, high blood pressure and diabetes can be a cause