Chapter 15 - Brain and Cranial Nerves

Question 1

Gray Matter

Answer 1

• outer part (cortex) of cerebrum and of cerebellum, as well as deep nuclei
• neurosomas, dendrites, and synaspes

Question 2

White Matter

Answer 2

• deep in brain

- bundles of mylinated axons

Question 3

Ventricles

Answer 3

chambers filled with CSF and lined by ependymal cells

• lateral ventricles (connected by interventricular foramen)
• third ventricles (connected to fourth by cerebral aqueduct)
• fourth venttricle (central canal)

Question 4

Cerebrospinal Fluid (CSF)

Answer 4

clear, colorless liquid = plasma that is filtered and modified by ependymal cells

• produced by choroid plexus within ventricles
• flows within ventricles, canals, and subarachnoid space around CNS
• absorbed by arachnoid granulations into blood of superior sagittal sinus

Question 5

Functions of CSF

Answer 5

1. Buoyancy
2. Protection
3. Chemical Stability

Question 6

Brain Blood Supply

Answer 6

• brain is 2% of body weight
• receives 15% of blood
• receives 20% of oxygen and glucose

Question 7

Blood-Brain Barrier

Answer 7

• isolation from general circulation
• seals capillaries in brain tissue (astrocytes)
• tight junctions between endothelial cells

Question 8

Blood-CSF Barrier

Answer 8

• seals choroid plexus within brain ventricles (ependymal cells)
• tight junctions between ependymal cells

Question 9

Medulla Oblongata

Answer 9

Several important nuclei:

1. Cardiac center
   
   • regulated rate and force of heartbeat
2. Vasomotor center
   
   • regulates blood pressure
3. Respiratory center
   
   • breathing, speech, coughing, sneezing, salivation, swallowing, gagging, and vomiting

Question 10

Pons

Answer 10

• facial sensation and expression
• control of chewing, respiration, and sleep
• many tracts and relay centers

Question 11

Midbrain

Answer 11

• nuclei that process visual and auditory information and control reflexes triggered by them
• cerebral aqueduct passes through
• centers that control consciousness

Question 12

Reticular Formation

Answer 12

• web of gray matter that runs through all levels of brainstem
• regulates vital autonomic functions
  1. Somatic motor control
  2. Cardiovascular control
  3. Pain modulation
  4. Sleep and consciousness
  5. Habituation

Question 13

Cerebellum

Answer 13

• autonomic processing center
  
  • adjusts postural muscles (balance and equilibrium)
  • fine tunes & programs movements (e.g. riding a bike)
• Cortex of folia - gray matter
  
  • Purkinje cells (receive input)
  • deep nuclei (coordinate and control body movements)
• Arbor vitae - white matter
  
  • connects cortex and nuclei w/ peduncles

Question 14

Diencephalon

Answer 14

• part of forebrain
• three divisions that surround third ventricle
  
  1. Thalamus
  2. Hypothalamus
  3. Epithalamus
• integrates sensory information with motor output

Question 15

Thalamus

Answer 15

• gateway to the cortex

- involved in sensation, movement, memory, and emotion

Question 16

Hypothalamus

Answer 16

• relay signals from limbic to thalamus
• major control center of the autonomic nervous system and endocrine system
• Functions:
  
  1. Hormone secretion (ADH & OXT)
  2. Autonomic effectors
  3. Thermoregulation
  4. Sleep and circadian rhythms
  5. Emotional & behavioral drives

Question 17

Epithalamus

Answer 17

• thin rood over third ventricle
• pineal gland (endocrine) - melatonin
• habenula - relay from limbic system to midbrain

Question 18

Frontal Lobe

Answer 18

• cognition
• speech
• motor control

Question 19

Parietal Lobe

Answer 19

interprets signals of general senses and taste

Question 20

Occipital Lobe

Answer 20

principle visual center

Question 21

Temporal Lobe

Answer 21

• hearing
• smell
• learning
• memory

Question 22

Insula

Answer 22

• taste
• visceral sensation
• language

Question 23

Association tracts

Answer 23

connect regions within same hemisphere

Question 24

Commissural tracts

Answer 24

cross between two hemispheres (corpus callosum is largest)

Question 25

Projection tracts

Answer 25

travel vertically to carry information between cerebrum and rest of body

Question 26

Cerebral Cortex

Answer 26

• surface of the hemispheres
• 40% of mass of brain
• stellate cells
  
  • short dendrites, no axon
  • local processing of sensory info
• pyramidal cells
  
  • output neurons of cerebrum (only neurons that exit the cortex)
• “neocortex” - six layers, recently evolved = highest development in mammals

Question 27

Limbic System

Answer 27

• nuclei and tracts “functional grouping”
• important function for:
  
  • emotion
  • motivation
  • memory
• multiple gratification and aversion centers

Question 28

Vision = _______ lobe

Answer 28

occipital

Question 29

Hearing = ________ lobe

Answer 29

temporal

Question 30

Equilibrium = _______ & several _________ _______

Answer 30

cerebellum, brainstem nuclei

Question 31

Taste = _______ lobe

Answer 31

parietal

Question 32

Smell = _______ & _______ lobes

Answer 32

temporal, frontal

Question 33

Broca Area

Answer 33

speech and language

Question 34

Wernicke Area

Answer 34

recognition of written and spoken language

Question 35

Postcentral gyrus

Answer 35

receives sensory information

Question 36

Precentral gyrus

Answer 36

primary motor cortex