C12 9-12

Question 0

What is the cerebral white matter made of?

Answer 0

Tracts that connect areas of the cerebral cortex to each other or to other parts of the CNS.

Question 1

Where is Cerebral/central white matter found?

Answer 1

White matter of the brain between the cortex and nuclei (cerebral medulla)

Question 2

What type of fibers are found in the cerebral white matter?

Answer 2

commisure, association fiber, projection fiber.

Question 3

Commissure

Answer 3

Connect corresponding grey areas of the two hemispheres and allow the two hemispheres to function as a coordinated whole.

Question 4

What is the largest commisure?

Answer 4

Corpus callosum - lies superior to the lateral ventricles deep within the longitudinal fissure (less prominent are the anterior and posterior commissures)

Question 5

Association fiber

Answer 5

Connect areas of the cortex within the same hemisphere. Short associatioin fibers connect adjacent gyri, long fibers connect different cortical lobes.

Question 6

Projection fiber

Answer 6

Connect the cerebrum to other parts of the brain and spinal cord.
The projection fibers form the internal capsule.

Question 7

Where are the basal nuclei found?

Answer 7

Deep within the cerebral white matter

Three nuclei: globus pallidus, putamen, caudate.

Question 8

What are the major functions of the basal (cerebral) nuclei?

Answer 8

1. inhibit muscle tone
2. inhibit unwanted muscle movement
3. start/stop movement.
   Also: help initiate and terminate some cognitive processes - attention, memory, planning.

Question 9

Input/output of basal nuclei

Answer 9

input - from the cerebral cortex

output - to motor areas of the cortex via the thalamus.

Question 10

What structures are closely associated with the basal nuclei?

Answer 10

Substantia nigra (plays a role in controlling basal nuclei) of the midbrain and subthalmic nuclei of the diencephalon.

Question 11

What are some disorders associated with the Basal Nuclei?

Answer 11

Parkinson’s disease, obsessive-compulsive, schizophrenia, chronic anxiety.
-dysfunctions of circuits between the basal nuclei and limbic system.

Question 12

Location of the diencephalon?

Answer 12

Central core of the forebrain, surrounded by the cerebral hemispheres

Question 13

Divisions of the diencephalon?

Answer 13

Thalamus, hypothalmus, epithalmus

Question 14

In which ways does the Thalamus relay information?

Answer 14

1. most sensory impulses (not olfaction)
   * *spinal cord and brain stem —> primary sensory areas of the cerebral cortex**
2. motor functions
   * *cerebellum and basal nuclei —> primary motor cortex**
3. between different areas of cerebrum (maintenance of consciousness.)

Question 15

Why is the thalamus an “executive secretary?”

Answer 15

It acts as an information filter, screening out most sensory info that arrives at the thalamus and fwding only a small portion to the cerebrum.
(i.e., filters out sounds and sights when you are studying)

Question 16

What portion of the diencephalon does the thalamus occupy?

Answer 16

80%

Question 17

What is the function of the hypothalmus?

Answer 17

• Regulates ANS activity (SWEET HAT)

- Serves as a relay station for reflexes related to smell and with the limbic system emotional and behavioural patterns.

Question 18

Hypothalmus - SWEET HAT

Answer 18

Sleep Wake (circadian)
Emotional brain Hq (limbic system)
Endocrine Hq
Thirst

Hunger - Autonomic Hq - Thermostat

Question 19

Epithalamus function

Answer 19

• Includes the pineal gland which secretes melatonin and helps regulate day/night/circadian rhythms.
• Includes the habenular nuclei which help relay signals from the limbic system to the midbrain and are involved in visceral and emotional responses to odors.

Question 20

Three major regions of the brainstem? (the mesencephalon)

Answer 20

Midbrain, Pons, Medulla oblongata

Question 21

What does the midbrain include?

Answer 21

cerebral peduncles
, substantia nigra,
Tegumentum,
tectum

Question 22

What does the pons include?

Answer 22

Conduction pathways, Pontine sleep center, Pontine respiratory center

Question 23

What does the Medulla Oblongata include?

Answer 23

Pyramids, cranial nerve nuclei, part of reticular formation,

cardiac center, vasomotor center, medullary respiratory center,

nuclei that are involved in coughing, sneezing, salivation, swallowing, gagging, vomiting.

Question 24

What are cerebral peduncles (midbrain)?

Answer 24

Motor tracts (midbrain)

Question 25

What are substantia nigra (midbrain)?

Answer 25

neurons that produce dopamine.

Dopamine affects brain processes to control muscle movement, emotional response and ability to experieince pleasure/pain.

Nigra = black color which is because it contains lots of melatonin (precursor to dopamine).
Degeneration of sn = parkinson’s.

Question 26

Which structure is responsible for the startle reflex?

Answer 26

Inferior colliculi in the tectum of the midbrain

Question 27

What is tegumentum (midbrain)?

Answer 27

Houses red nuclei and part of the reticular function.

Integrates info from the cerebrum and cerebellum and issues involuntary motor command to the erector spinae muscles of the back to help maintain posture.

Question 28

What is the tectum?

Answer 28

Consists of four nuclei that form mounds on the dorsal surface called corpora quadrigemina. Each mound is called a colliculus.

Two superior mounds are called superior colliculi (involved in reflex movements of the head, eyes, and body toward visual, auditory or tactile stimuli.

Two inferior mounds are inferior colliculi (involved in hearing and are important part of the auditory pathways in the CNS. STARTLE REFLEX!)

Question 29

Pontine sleep center

Answer 29

Initiates rapid eye movement in sleep

Question 30

Pontine respiratory center

Answer 30

Works with the respiratory centers in the medulla to help control respiratory movements.

Question 31

Beyond the sleep and respiratory center, what are the other functions of the Pons?

Answer 31

Bridge between brain and spinal cord
(Contains fiber tracts that complete conduction pathways between the brain and spinal cord.)

Pontine nuclei relay information from the cerebrum to the cerebellum. House nuclei for cranial nerves V, VI, VII, VIII and IX.

Question 32

What are the pyramids of the medulla oblongata?

Answer 32

They house motor projection tracts (corticospinal/pyramidal tracts), most of which cross to the opposite side (why the cerebral hemispheres control the opposite side of the body)

Question 33

What is the function of the cardiac center and where is it located?

Answer 33

Regulates heart rate and force of contraction

medulla oblongata

Question 34

What is the function of the vasomotor center and where is it located?

Answer 34

Controls blood pressure (changes diameter of blood vessels)

medulla oblongata

Question 35

What is the function of the medullary respiratory center?

Answer 35

Regulates respiratory rate

Question 36

What makes up the corpora quadrigemina, and where are they located?

Answer 36

Located in the tectum, midbrain.

Superior colliculi - reflex movements of the head, eyes, and body toward visual, auditory or tactile stimuli

Inferior colliculi - hearing, integral part of the auditory pathways of cns

Question 37

What are the nuclei in the medulla oblongata responsible for?

Answer 37

Coughing, sneezing, salivation, swallowing, gagging, vomiting

Question 38

Hypothalmic disturbances would cause?

Answer 38

Severe body wasting, obesity, sleep disturbances, dehydration, emotional imbalances, failure to thrive.