Unit Three: The Meninges

Question 1

What are the three connective tissue layers surrounding the brain?

Answer 1

1. Dura. 2. Arachnoid. 3. Pia.

Question 2

What are the functions of the cranial meninges? (4)

Answer 2

1. Cover and protect brain. 2. Enclose and protect blood vessels. 3. Stabilize the brain in the skull. 4. Contain cerebralspinal fluid.

Question 3

How do the meninges cover and protect the brain? (2)

Answer 3

1. Protect against foreign substances and trauma. 2. Separate the soft tissue of the brain from the bones of the skull.

Question 4

Are the meninges anchored to the skull? What is the brain suspended in?

Answer 4

Yes. The meninges.

Question 5

What is the outer, thickest layers of the meninges?

Answer 5

The dura mater.

Question 6

What are the two layers of the dura mater?

Answer 6

1. Periosteal. 2. Meningeal.

Question 7

Which layer of dura mater is fused to the periosteum on the inner aspect of the skull?

Answer 7

The periosteal layer.

Question 8

What does space between the periosteal and meningeal dura form?

Answer 8

Large collecting veins. Where veins of the brain empty into the sinuses.

Question 9

What are cranial dural reflections?

Answer 9

Where the meningeal layer of dura extends deep into the cranial cavity between sections of the brain.

Question 10

What are the functions of the cranial dural reflections? (3)

Answer 10

1. Subdivide cranial cavity. 2. Support brain. 3. Limit movement of the brain.

Question 11

Where is the falx cerebri?

Answer 11

Within the longitudinal fissure between the hemispheres.

Question 12

What does the falx cerebri contain? (2)

Answer 12

1. Inferior sagittal sinus. 2. Superior sagittal sinus.

Question 13

Where is the tentorium cerebelli located?

Answer 13

Between the occipital lobes of the cerebrum and the cerebellum.

Question 14

What is the thin, avascular, semitransparent membrane covering the brain?

Answer 14

Arachnoid mater.

Question 15

What is contained within the arachnoid mater?

Answer 15

Arachnoid granulations.

Question 16

What is the function of arachnoid granulations?

Answer 16

Send CSF from the subarachnoid space into the blood within the superior sagittal sinus.

Question 17

What is the thin, delicate connective tissue tightly attached to the brain?

Answer 17

The pia mater.

Question 18

Where does the pia mater follow?

Answer 18

All contours of the sulci and gyri.

Question 19

What does the pia mater do?

Answer 19

Supports large cerebral blood vessels.

Question 20

Where is the subarachnoid space?

Answer 20

Between the arachnoid and pia mater.

Question 21

Where are arachnoid trabeculae found and what are they?

Answer 21

In the subarachnoid space. They are web like threads

extending across the subarachnoid space from arachnoid mater to pia mater.

Question 22

What does the subarachnoid space contain? (2)

Answer 22

1. Cerebrospinal fluid. 2. Blood vessels.

Question 23

What is cerebrospinal fluid?

Answer 23

Colorless fluid that circulates in the ventricles and

subarachnoid space.

Question 24

What produces cerebrospinal fluid?

Answer 24

Choroid plexus found within all ventricles of the brain.

Question 25

What do choroid plexes contain?

Answer 25

Specialized ependymal cells and highly permeable capillaries.

Question 26

Is cerebrospinal fluid always being produced?

Answer 26

Yes.

Question 27

What is another function of choroid plexes?

Answer 27

Removes waste from CSF and alters its composition if needed.

Question 28

How does CSF move through the brain? (3)

Answer 28

1. Movement of cilia on the ependymal cells. 2. Movements of the vertebral column moving it around the spinal cord. 3. Pressure from the constant production forcing it out through the arachnoid granulations.

Question 29

What are 4 functions of CSF?

Answer 29

1. Buoyancy. 2. Protection. 3. Environmental stability. 4. Transports hormones, waste, nutrients, and chemicals.

Question 30

What is the function of the blood brain barrier?

Answer 30

Tightly regulates what can leave the blood vessels and enter the space surrounding the brain tissue.

Question 31

What kind of capillaries are found in the blood brain barrier?

Answer 31

Continuous.

Question 32

What prevents materials from diffusing between epithelial cells in the blood brain barrier?

Answer 32

Extensive tight junctions.

Question 33

What surrounds the capillaries of the blood brain barrier?

Answer 33

Astrocyte perivascular feet.

Question 34

What restricts the permeability of the capillary epithelial cells in the blood brain barrier?

Answer 34

Astrocytes.

Question 35

Where is there increased permeability in the blood brain barrier and why? (3)

Answer 35

1. By the hypothalamus and pituitary glands in order to allow for hormone diffusion. 2. By the pineal gland. 3. Choroid plexes.

Question 36

Where are the lateral ventricles? What are they separated by?

Answer 36

In each hemisphere. They are separated by the midline septum pellucidum.

Question 37

Where is the 3rd ventricle?

Answer 37

Midline, between the right thalamus and left thalamus.

Question 38

Where is the 4th ventricle?

Answer 38

Between the pons and cerebellum, extending into the superior portion of the medulla oblongata.

Question 39

What connects the lateral ventricle to the 3rd ventricle?

Answer 39

Interventricular foramen.

Question 40

What connects the 3rd ventricle to the 4th ventricle?

Answer 40

The cerebral aqueduct.

Question 41

How can CSF leave the 4th ventricle? (3)

Answer 41

1. Lateral aperture. 2. Median aperture. 3. Central canal of the spinal cord.

Question 42

Describe the first step of the longest possible path that CSF can take. (3)

Answer 42

1. Lateral ventricles. 2. Interventricular foramen of | Monro. 3. 3rd ventricle

Question 43

Describe the second step of the longest possible path that CSF can take. (3)

Answer 43

1. 3rd ventricle. 2. cerebral aqueduct. 3. 4th ventricle

Question 44

Describe the third step of the longest possible path that CSF can take. (2)

Answer 44

1. 4th ventricle. 2. One of these routes into the | subarachnoid space: Paired lateral apertures, midline median aperture, central canal of the spinal cord.

Question 45

Describe the fourth step of the longest possible path that CSF can take.

Answer 45

CSF enters the arachnoid space.

Question 46

Describe the fifth step of the longest possible path that CSF can take.

Answer 46

CSF flows into arachnoid granulations, which | transport it into the dural venous sinuses.

Question 47

What are the major dural venous sinuses? (5)

Answer 47

1. Superior sagittal sinus. 2. Inferior sagittal sinus. 3. Transverse sinus. 4. Straight sinus. 5. Confluence of sinuses.