Chapter 14 - Brain

Question 1

What is the function of CSF?

Answer 1

1. Buoyancy - floats brain so that it doesn’t crush under its own weight
2. Protection - protects brain from bumping into cranium during jolting movement
   - -Concussion is a case of failed brain protection!
3. Chemical Stability - carries metabolic waste –> filters it through kidneys –> reabsorbed into blood plasma)

Question 2

Where is CSF made?

Answer 2

CSF is made by Ependymal cells in the…

• -Choroid plexus (in each ventricle)
• -Subarachnoid space

Question 3

Describe the the pathway of CSF

Answer 3

Lateral ventricles –> third ventricle –> fourth ventricle –> subarachnoid space –> dural sinus –> *circulatory system (heart + lungs) –> choroid plexuses (reabsorbs CSF as blood plasma)

Question 4

What are the four fluid-filled chambers in the brain?

Answer 4

Ventricles - four chambers containing CSF
Lateral ventricles (2)
Third Ventricle
Fourth Ventricle

Question 5

Regulates the entry of substances into the brain (blocks potentially harmful substances…toxins, pathogens, etc.)

Answer 5

Blood Brain Barrier (BBB)

Question 6

Where is the Blood Brain Barrier missing + why?

Answer 6

BBB missing in…

• -Circumventricular organs (CVOs)
• -Third + Fourth ventricles - route for HIV invasion!

Why?
–These locations must monitor physiological conditions (glucose, pH, osmolarity, etc.)

Question 7

What three brain parts are considered to be the brain stem?

Answer 7

1. Midbrain
2. Pons
3. Medulla oblongata

Question 8

Nuclei that extend up through the brainstem and into the midbrain

Answer 8

Recticular formation

Question 9

What important physiological functions are controlled by the reticular formation?

Answer 9

1. Somatic motor control - muscle tone, balance, posture, breathing, etc.
2. Cardiovascular control
3. Pain modulation - descending analgesic (painkiller) pathways block pain transmission
4. Sleep/Consciousness - controls alertness
   - -Reticular activating system - arouses + maintains consciousness
5. Habituation - learning to ignore repetitive stimuli

Question 10

What is the corpora quadrigemina?

Answer 10

Tectum - contains the corpora quadrigemina (4 baby bodies)

• -Superior colliculi (2) - visual attention + “eye tracking”, involved in reflex response
• -Inferior colliculi (2) - receives signals from inner ear, involved in balance + hearing`

Question 11

A region of gray matter on either side of the cerebral aqueduct in the midbrain.

Answer 11

Tegmentum

Question 12

Dorsal part of the midbrain

Answer 12

Tectum

Question 13

What are the parts of the Tegmentum?

Answer 13

1. Red nucleus - fine motor control (along w/ cerebellum)
2. Substantia nigra - sends inhibitory signals –> thalamus
   - -Prevents unwanted body movements
   - -Degeneration of this = muscle tremors

Question 14

What are the three parts of the Diencephalon? What do they do?

Answer 14

1. Thalamus “Gatekeeper” - filters stimuli + relays signals from cerebellum –> cerebrum
   - -Involved in senses
2. Hypothalamus “Master Gland” - controls ANS and endocrine system
   - -Involved in hormones, heart rate, BP, thermoregulation
3. Epithalamus (Pineal Gland) - controls diurnal rhythms
   - -Involved in production of melatonin, and ultimately sleep

Question 15

What does the Cerebellum control?

Answer 15

Complex movements (motor control, “muscle memory” etc.)

Question 16

What are the consequences to injury of the Cerebellum?

Answer 16

• -Cerebellar lesions - deficit in coordination, locomotion, linguistics, emotions + non-motor functions like difficulty planning
• -Small cerebellums - related to ADHD in children

Question 17

Worm-like structure that separates the cerebellum into two hemispheres

Answer 17

Vermis

Question 18

What is the function of the Vermis?

Answer 18

Maintains equilibrium

Question 19

What are the three nerve tracts of the brain?

Answer 19

1. Projection fibers - connect inferior + superior regions of the brain
2. Association tracts - connect parts of a lobe that communicate w/ one another (usually for the same purpose)
3. Commissural tracts - connect L + R hemispheres, pass through the corpus callosum

Question 20

Part of the cerebral cortex involved in high-order brain functions in mammals

Answer 20

Neocortex

Question 21

What are the different roles played by Stellate and Pyramidal neurons?

Answer 21

1. Stellate - SENSORY
   - -Take in sensory info
2. Pyramidal - MOTOR (OUTPUT)
   - -Respond to stimuli

Question 22

In which cerebral lobe does motor function and personality reside?

Answer 22

Frontal

Question 23

Which cerebral lobe provides sensory information about your skin and muscles?

Answer 23

Parietal

Question 24

Which cerebral lobe receives and processes visual stimuli?

Answer 24

Occipital

Question 25

In which cerebral lobe are auditory signals processed?

Answer 25

Temporal

Question 26

What two cerebral locations are responsible for speech?

Answer 26

Cerebral Cortex: - -Broca's Area - motor-speech (Frontal lobe) - -Wernicke's Area - interprets speech (where Parietal + Temporal lobe meet)

Question 27

What cerebral lobe is buried deep inside the transverse sulcus? What is its job?

Answer 27

Insula - understanding spoken language, taste, visceral sensation

Question 28

What are the parts of the Limbic system?

Answer 28

1. Cingulate gyrus - coordinates sensory info w/ emotions 2. Mammillary bodies 3. Fornix 4. Hippocampus - organizes long-term memory (memory consolidation) - -Dentate gyrus - place where new memories are established (new neurons --> new memories) 5. Amygdala - draw attention to novel stimuli

Question 29

Place where new memories are established

Answer 29

Dentate gyrus of Hippocampus

Question 30

What dire consequence for survival might occur if the Amygdala is damaged by a brain injury?

Answer 30

Inability to feel fear - -Creates a safety hazard; unable to be cautious of dangerous situations ex: crossing the street

Question 31

Coma-like state in which we can be aroused by stimulation

Answer 31

Sleep

Question 32

Sleep + comas are similar in ____ ____ activity.

Answer 32

brain wave

Question 33

What are the stages of sleep?

Answer 33

1, 2, 3, 4, REM, 4, 3, 2, 1 Shallow: 1 - 3 Deep: 4

Question 34

In what stage of sleep does dreaming occur + body muscles become paralyzed?

Answer 34

REM - Rapid Eye Movement

Question 35

What are some side effect from a lack of sleep?

Answer 35

- -Increased risk of stroke, heart attack, and psychosis | - -Immune system depression --> death!

Question 36

Type of brain waves during mental activity + sensory stimulation Where are they located?

Answer 36

Beta | Frontal - Parietal

Question 37

Type of brain waves during awake, but relaxed phases Where are they located?

Answer 37

Alpha | Parietal - Occipital

Question 38

Type of brain waves used during deep relaxation or meditation What is this brain wave also associated with?

Answer 38

Theta | Also associated w/ emotional stress + brain disorders

Question 39

Type of brain waves used during deep sleep in adults Does dreaming take place in this state?

Answer 39

Delta | NOT associated w/ dreaming

Question 40

What three cranial nerves are responsible for your sense of smell, vision, and hearing?

Answer 40

1. Olfactory (I) - smell 2. Optic (II) - vision 3. Vestibulocochlear (VIII) - hearing

Question 41

What three cranial nerves are responsible for eye movements?

Answer 41

1. Oculomotor (III) 2. Trochlear (IV) 3. Abducens (VI)

Question 42

Which cranial nerve is responsible for facial sensations?

Answer 42

Trigeminal (V)

Question 43

Damage to which cranial nerve will result in the loss of facial muscle control and distorted tastes?

Answer 43

Facial (VII)

Question 44

Which two cranial nerves are involved in the process of swallowing?

Answer 44

Glossopharyngeal (IX) + Vagus (X)

Question 45

Which cranial nerve is primarily in control of the ANS?

Answer 45

Vagus (X)

Question 46

Which cranial nerve controls shoulder movements?

Answer 46

Accessory (XI)

Question 47

Which cranial nerve is responsible for tongue movements?

Answer 47

Hypoglossal (XII)