Brain and Cranial Nerves

Question 1

What does the term “rostral” mean in regards to the brain?

Answer 1

Toward the forehead

Question 2

What does the term “caudal” mean in regards to the brain?

Answer 2

Toward the spinal cord

Question 3

What does the term “rostral” mean in regards to the spinal cord/brainstem?

Answer 3

Higher

Question 4

What does the term “caudal” mean in regards to the spinal cord/brainstem?

Answer 4

Lower

Question 5

What are the three major portions of the brain?

Answer 5

Cerebrum, cerebellum, and brainstem

Question 6

What percent of the brain’s volume is the cerebrum, and what does it include?

Answer 6

83%, consists of pair of half globes called cerebral hemispheres marked by thick folds called gyri separated by shallow grooves called sulci

Question 7

What is the name of the groove separating the two hemispheres of the brain?

Answer 7

longitudinal fissure

Question 8

What is the think bundle of nerve fibers at the bottom of the longitudinal fissure that connects the hemispheres?

Answer 8

corpus callosum

Question 9

Where is the cerebellum located and what separates it from the cerebrum? What % of volume does it make up?

Answer 9

posterior cranial fossa, inferior to cerebrum, separated by the transverse cerebral fissure, makes up 10% of brain’s volume

Question 10

Which portion of the brain contains the majority of the neurons? What percent are in this portion?

Answer 10

Cerebellum, contains 50% of neurons

Question 11

What does the brainstem consist of?

Answer 11

All of the brain except the cerebellum and cerebrum

Question 12

List the major components of the brainstem, from rostral to caudal

Answer 12

diencephalon, midbrain, pons, and medulla oblongata

Question 13

Where does the brainstem end?

Answer 13

foramen magnum of the skull

Question 14

What is the seat of the neurosomas, dendrites, and synapses; and forms a surface layer called the cortex over the cerebrum and cerebellum; and deeper masses called nuclei surrounded by white matter?

Answer 14

grey matter

Question 15

where is white matter in relation to grey matter in the brain?

Answer 15

deep to the cortical grey matter in most of the brain

Question 16

what is white matter composed of?

Answer 16

tracts, or bundles of axons, which connect one part of the brain to another and to the spinal cord

Question 17

What tissue layer of an embryo does the nervous system develop from?

Answer 17

ectoderm

Question 18

Describe how brain develops during embryonic development

Answer 18

first 3 weeks: neural plate forms along dorsal midline of embryo, forms neural groove with raised neural folds on each side. folds roll toward each other and fuse. creates neural tube by day 26. tube separates from ectoderm, sinks, and grows lateral processes that form motor nerve fibers. lumen of tube becomes central canal
neural crest forms and gives rise to two inner meninges (arachnoid mater and pia mater); most of PNS, and other structures
by week 4: neural tube exhibits three anterior dilations, forebrain (primary vesicles, prosencephalon), midbrain (mesencephalon), and hindbrain (rhombencephalon)
5th week: brain subdivides into 5 secondary vesicles- forebrain into telencephalon and diencephalon; midbrain undivided; hindbrain into metencephalon and myelencephalon
telencephalon becomes the cerebral hemispheres, diencephalon become retinas of eyes