chapter 14

Question 1

where is the majority of the body’s neural tissue?

Answer 1

in the brain (97%)

Question 2

how much does the brain weigh?

Answer 2

1.4 kg (3 lbs)

Question 3

what is the typical brain volume?

Answer 3

750 ml to 2100 ml

Question 4

what are the six regions of the brain?

Answer 4

cerebrum, cerebellum, diencephalon, midbrain, pons and medulla oblongata

Question 5

where in the brain is conscious thought and intelligence produced?

Answer 5

neural cortex

Question 6

cerebrum

Answer 6

• largest portion of the brain
• origination of conscious thoughts, sensations, memory, complex movements
• made of two cerebral hemispheres

Question 7

cerebellum

Answer 7

• 2nd largest part of the brain
• adjusts ongoing movements
• coordinates repetitive body movements
• covered by cerebellar cortex
• coordinates skeletal muscle contractions
• maintains muscle tone and posture

Question 8

diencephalon

Answer 8

• made of thalamus (3 divisions)
• links the cerebrum with the brain stem

Question 9

thalamus

Answer 9

relays and processes sensory information

Question 10

hypothalamus

Answer 10

floor of diencephalon
- controls hormone production, emotions and autonomic function

Question 11

what connects the hypothalamus to the pituitary gland?

Answer 11

the infundibulum

Question 12

pituitary gland

Answer 12

major endocrine gland that integrates nervous and endocrine systems

Question 13

what does the brainstem do?

Answer 13

processes information between the spinal cord and cerebrum or cerebellum

Question 14

what does the brainstem consist of?

Answer 14

the brainstem is made up of the midbrain, pons and medulla oblongata

Question 15

midbrain

Answer 15

aka mesencephalon
- processes visual and auditory information/reflexes
- maintains consciousness
- controls reflex responses

Question 16

pons

Answer 16

connects the cerebellum to the brain stem
- houses tracts involved in somatic and visceral motor control

Question 17

medulla oblongata

Answer 17

connects the brain to the spinal cord
- relays information
- regulates autonomic functions (HR, BP, vasoconstriction, digestion)
- contains portions of motor and sensory tracts

Question 18

reticular formation

Answer 18

regulates muscle tone
alerts cortex to incoming signal
maintains consciousness

Question 19

what is the brain protected by?

Answer 19

cranium bones, cranial meninges and CSF
and BBB

Question 20

dura mater

Answer 20

consists of outer and inner fibrous layers
- meningeal and periosteal layer
- venous sinuses between two layers

Question 21

arachnoid mater

Answer 21

covers the brain, comes in contact with the dura mater
weblike, avascular

Question 22

pia mater

Answer 22

attached to the brain by astrocytes

Question 23

dural folds

Answer 23

inward folds in the meningeal dura mater
provide stabilization for the brain
contain dural sinuses (collecting veins)

Question 24

what are the three dural folds?

Answer 24

falx cerebri
tentorium cerebelli
falx cerebelli

Question 25

falx cerebri

Answer 25

- projects between cerebral hemispheres - contains superior and inferior sagittal sinuses (venous sinuses)

Question 26

tentorium cerebelli

Answer 26

- separates cerebellum and cerebrum - transverse sinus which runs across the occipital bone to drain blood from the back of the head

Question 27

falx cerebelli

Answer 27

divides the cerebellar hemispheres into two

Question 28

cerebrospinal fluid

Answer 28

- surrounds the CNS - cushions delicate neural structures - supports the brain - transports nutrients, chemical messengers and waste

Question 29

what is a choroid plexus?

Answer 29

area within each brain ventricle that produces CSF - made of special ependymal cells - produces about 500 mL of CSF a day

Question 30

CSF circulation route

Answer 30

choroid plexus - ventricles- central canal- subarachnoid space through apetures

Question 31

a problem with CSF resorption in infants can cause what?

Answer 31

hydrocephaly

Question 32

cranial trauma

Answer 32

head injury resulting from impact with another object

Question 33

what absorbs CSF into venous circulation?

Answer 33

arachnoid granulations

Question 34

how does arterial blood reach the brain?

Answer 34

though internal carotid arteries and vertebral arteries

Question 35

how does venous blood leave the brain?

Answer 35

through internal jugular veins in the dural sinuses

Question 36

importance of blood flow to the brain

Answer 36

- uses about 20% of body's oxygen supply - lack of oxygen can result in weakening or permanent damage of brain cells

Question 37

glucose deficiency may produce

Answer 37

mental confusion, dizziness and unconsciousness

Question 38

cerebrovascular disease

Answer 38

cardiovascular disorders that interfere with blood circulation to the brain

Question 39

CVA

Answer 39

aka a stroke is when blood supply to a part of the brain is shut off neurons will die

Question 40

how is nervous tissue in the CNS isolated?

Answer 40

by the BBB

Question 41

What forms the BBB?

Answer 41

capillary endothelial cells interconnected by tight junctions

Question 42

what kind of compounds can cross the BBB?

Answer 42

- lipid soluble - CO2, O2, ammonia, steroids, prostaglandins

Question 43

what do astrocytes do for the BBB?

Answer 43

release chemicals that control endothelium permeability (nutrients, ions)

Question 44

blood CSF barrier

Answer 44

- made of specialized ependymal cells that surround the choroid plexus capillaries - limit compound movement into the CNS - allow chemical comp. of blood and CSF to differ

Question 45

where won't you find the BBB?

Answer 45

1. parts of the hypothalamus 2. posterior lobe of pituitary gland (secretes ADH and oxytocin) 3. pineal gland 4. choroid plexus because ependymal cells maintain the blood CSF barrier