chapter 14

Question 1

what did aristotle think about the brain

Answer 1

he thought it just cooled blood

Question 2

what does rostral mena

Answer 2

toward the forehead = superior / anterior

Question 3

what does caudal mean

Answer 3

it means toward the spinal cord

=posterior/inferior

Question 4

what are the three major portions of the brain

Answer 4

cerebrum

cerebellum

brainstem

Question 5

cerebrum

Answer 5

83% of brain volume

2 cerebral hemispheres

it has gyri and sulci

it has the longitudnal fissure and the corpus callosum

Question 6

cerebellum

Answer 6

contains 50% of the neurons from the brain

10% brains volume

second largest brain region

located postereior cranial fossa

has gyri, sulci, and fissures

Question 7

brain stem

Answer 7

portion of the brain that remains if the cerebrum and cerebellum are removed

contains:

• diencephalon
• midbrain
• pons
• and medulla oblongata

foramen magnum is the boundary

Question 8

what is gyri vs sulci

Answer 8

gyri are the thick folds

sulci are the shallow grooves between them

Question 9

what is the longitudinal fissure

Answer 9

deep groove that separates cerebral hemispheres

Question 10

what is the corpus callosum

Answer 10

thick nerve bundle at bottom of longitudinal fissure that connects hemispheres

horses dont have

Question 11

what separates the cerebellum from the cerebrum

Answer 11

transverse cerebral fissure

Question 12

what is grey matter

Answer 12

processing region

lots of nisel bodies, neurosomas , dendrites, and synapses

Dull color due to little myelin

Forms surface layer (cortex) over cerebrum and cerebellum

Forms basal nuclei deep within brain

Question 13

what is white matter

Answer 13

info transver

bundles of axons

(sandwhiched between gray) Lies deep to cortical gray matter, opposite relationship in the spinal cord

Pearly white color from myelin around nerve fibers

smaller neruosomas

bigger in general

Composed of tracts, or bundles of axons, that connect one part of the brain to another, and to the spinal cord

Question 14

how is the grey/white matter organized in the brain stem

Answer 14

mixed together

Question 15

how is the grey/white matter organized in the spinal cord

Answer 15

opposite the cerebrum

white is superficial

Question 16

what are meniges

Answer 16

three connective tissue membranes that envelop the brain

Lie between the nervous tissue and bone

As in spinal cord, they are the dura mater, arachnoid mater, and the pia mater

Protect the brain and provide structural framework for its arteries and veins

Question 17

cranial dura mater

Answer 17

most superficial

it has two layers

dura mater is pressed closely against cranial bones (no epidural space)

has the most collagen/heaviest/thickest

not directly attached to bone except: around foramen magnum , sella turcica, crista galli, and sutures of the skull

folds inward to extend between parts of the brain

Question 18

what are the two layers of the cranial dura mater

Answer 18

outer periosteal
-equivalent to periosteum of cranial bones
connects to the cranial bones

inner meningeal layer
-continues into vertebral canal and forms dural sheath around spinal cord

Question 19

what are the two layers of dura mater separated by

Answer 19

they are separated by dural sinuses

collect blood circulating through the brain

Question 20

what are the

flax cerebri

tentorium cerebelli

flax cerebelli

Answer 20

inward folds of the cranial dura mater

Falx cerebri separates two cerebral hemispheres

Tentorium cerebelli separates cerebrum from cerebellum

Falx cerebelli separates right and left halves of cerebellum

Question 21

arachnoid mater

Answer 21

Transparent membrane over brain surface

Subarachnoid space separates it from pia mater below
( contains cerebral spinal fluid)
modified reticular tissue (loose connective tissue)

Subdural space separates it from dura mater above in some places (blood vessels)

aka the middle layer

Question 22

pia matter

Answer 22

Very thin membrane that follows contours of brain, even dipping into sulci

deepest layer

Not usually visible without a microscope

loose connective tissue(mod reticular/aerolar tissue)

not a lot of collagen

separates active neuorns from any cerebral spinal fluid

Question 23

meningitis

Answer 23

inflammation of the meniges

serious for infancy and childhood especially 3 months to 2 years of age

caused by bacterial or viral invasion of the CNS (nose/throat)

pia and arachnoid are most affected

Question 24

what are the side effects of meningitis

Answer 24

swelling of the brain

enlargement of the ventricles

hemorrhage

signs: high fever, stiff neck, drowsiness, intense headache

can cause coma or death

diagnosed via examination of the cerebral spinal fluid obtained by lumbar puncture (spinal tap)

Question 25

ventricles

Answer 25

the second form of protection for the brain it has four internal chambers allows for exchange of nutrients to deeper layers

Question 26

name the four ventricles

Answer 26

two lateral ventricles -one in each cerebral hemisphere third ventricle -narrow medial space beneath corpus collasum fourth ventricle -small triangluar champber between pons and cerebellum

Question 27

how are all the ventircles connected

Answer 27

interventricular foramen connects the lateral ventricles to the third ventiricle cerebral aqueduct runs through midbrain and connects third to fourth the fourth connects to central canal that runs through spinal cord

Question 28

what is the choroid plexus

Answer 28

spongy mass of blood capillaries on the floor of each ventricle where cerebra spinal fluid is made

Question 29

what is the ependyma

Answer 29

type of neuroglia that lines ventricles and covers choroid plexus Produces cerebrospinal fluid

Question 30

what is cerebrospinal fluid

Answer 30

clear, colorless liquid that fills the ventricles and canals of CNS brain produces and absorbs 500 ml/day (most formed in subarachnoid space, but also formed in general epedymal lining, and the choriod plexuses) production begins with filtration of blood plasma through capillaries of the brain (modified with increase sodium and chloride, less potassium/calcium/glucose)

Question 31

what is the function of CSF

Answer 31

buoyancy protection -prevents jolting from hurting cranium chemical stability -flow of it rinses away metabolic waste and regulates chem enviro

Question 32

blood brain barrier

Answer 32

protects blood capillaries throughout brain tissue consists of tight junctions between endothelial cells = capillary walls astorcytes reach out and contract capillaries with perivascular feet anything leaving blood must pass through the cells (not between) help exclude harmful substances from passing into brain tissue

Question 33

Blood CSF barrier

Answer 33

protects brain at the choroid plexus forms tight junctions between ependymal cells highly permeable to water, glucose and lipid souluble substances (O2, CO2, alcohol, caffeine, nicotine, anesthetics) slightly permeable to sodium, potassium, chloride, waste products (urea)

Question 34

blood brain system

Answer 34

The brain barrier system (BBS) can be an obstacle for delivering medications such as antibiotics and cancer drugs Trauma and inflammation can damage BBS and allow pathogens to enter brain tissue

Question 35

Circumventricular organs (CVOs)

Answer 35

places in the third and fourth ventricles where the barrier is absent Blood has direct access to the brain Enables the brain to monitor and respond to fluctuations in blood glucose, pH, osmolarity, and other variables CVOs afford a route for invasion by the human immunodeficiency virus (HIV)