Ch.12

Question 1

Cerebrum

Answer 1

• largest part of the brain
• Majority of brain mass (83%)
• Superficial gray matter - cerebral cortex
• deeper white matter: tracts
• deepest are the cerebral nuclei (basal ganglia – gray matter)

Question 2

Cerebellum

Answer 2

cauliflower shape

Question 3

Diencephalon

Answer 3

thalamus, hypothalamus, epithalamus

Question 4

Brain stem

Answer 4

• continuous with the spinal cord
• Consists of medulla, pons, and midbrain

Question 5

Brain Anatomy

Answer 5

deep gray matter (neuron cell bodies) –> white matter (myelinated fiber tracts) –> superficial gray matter

Question 6

Ventricles

Answer 6

• Fluid (CSF) fills these spaces in brain, all connected to each other and to central canal of spinal cord
  1. Lateral ventricles
• Pockets into the cerebral hemispheres
  2. Third ventricle
• Narrow canal through the diencephalons
  3. Fourth ventricle
• Canal under brain stem

Question 7

Cerebral Spinal Fluid

Answer 7

• Colorless liquid: circulates through the subarachnoid space of the brain, spinal cord, ventricles , central canal of cord
• Function: cushion brain and cord, provide buoyancy, circulates nutrients for optimal neuron functioning and eliminates waste products
• Made by ependymal cells of choroid plexus located in each ventricles.
• returned to circulatory system (dural sinuses) by the arachoid villi

Question 8

The Blood-Brain Barrier

Answer 8

• Endothelial cells have tight junctions, thick basement membranes - form a seal so only selected substances enter the brain
• Barrier is ineffective against fats, fatty acids, oxygen, carbon dioxide. Nicotine, alcohol, and anesthetics affect the brain as they are fat soluble