Anatomy of Developing Nervous System

Question 1

What are the 3 primary tissues (or “germ layers”) shared by embryos of animals?

Answer 1

1) Ectoderm
2) Mesoderm
3) Endoderm

Question 2

What is Gastrulation?

Answer 2

The process by which an embryo transforms from a one dimensional layer of epithelial cells known as a blastula (hollow ball stage) into a multilayered structure called a gastrula (3 layers)

Question 3

What is Neurulation?

Answer 3

the formation of the neural tube via rapid growth rate, cell movement, and changes to cell shape

Question 4

What does the ectoderm eventually form?

Answer 4

The ectodermal cells become the epidermis (skin) and nervous system (neuroectoderm)

Question 5

What does the mesoderm eventually become?

Answer 5

Muscles and skeleton

Question 6

What does the endoderm become?

Answer 6

the gut and associated organs

Question 7

What is the “Anterior” side of an embryo & what is also known as?

Answer 7

aka rostral or “pertaining to a break”

end of embryo where head forms

Question 8

Which direction is Posterior and what is another term for it in reference to an embryo?

Answer 8

aka caudal = “pertaining to a tail”

opposite end of the head of the embryo

Question 9

What are the 2 types of Neurulation?

Answer 9

1) Primary

2) Secondary

Question 10

What is Primary Neurulation?

Answer 10

when the neural plate roles up to form the neural tube

Question 11

What is Secondary Neurulation?

Answer 11

process of forming the neural tube involving hollowing out an initially solid rod of tissue

Question 12

What is a Blastula?

Answer 12

animal embryo at the early stage of development when it is a hollow ball of cells

Question 13

What is a Blastocyst?

Answer 13

embryo that forms after the sperm fertilizes an egg prior to gastrulation

Question 14

What can result as a failure of neurulation?

Answer 14

Neural tube defects

Question 15

What are the 2 most common neural tube defects and what is the prevelance?

Answer 15

1) Anencephaly - cranial neural folds do not fuse in the developing embryo resulting in most or all of the brain missing
2) Spina Bifida - failure of the neural tube to fuse at its caudal end resulting in an open lesion with damage to the nerves & spinal cord or a closed lesion.

Prevelance = 1/ 1000 births

Question 16

What is a Stem cell?

Answer 16

unspecialized cell that can divide repeatedly to regenerate itself and give rise to more specialized cells (such as neurons or glia)

Question 17

What are parts of the Central Nervous System (CNS) & what are its main functions?

Answer 17

• Includes the Brain, Spinal Cord, & Retina

- Responsible for information processing and memory storage

Question 18

What is the Peripheral Nervous System (PNS) and what are its main functions?

Answer 18

• Made of all the neurons outside of the CNS
• Extracts sensory information from the internal and external environment (in & around the body) and passes it to the CNS
• Controls actions of the body

Question 19

Bipolar Neuron

Answer 19

Neuron with 2 projections emanating from the cell body or soma

Question 20

Multipolar Neuron

Answer 20

Type of neuron that has a single axon and several dentrites extending from its body

Question 21

In vertebrates, where does the Peripheral Nervous System originate from?

Answer 21

The Neural crest which originates from the Neuroectoderm germ layer

Question 22

What are Autonomic Neurons?

Answer 22

Neurons in the PNS that control body functions below level of consciousness such as:

• respiration
• heart rate
• digestion

Question 23

What are Schwann Cells?

Answer 23

glial cells of the PNS that produce myelin sheath around axons

Question 24

The anterior part of the neural tube forms:

Answer 24

1) the forebrain
2) the midbrain
3) the hindbrain

Question 25

The posterior part of the neural tube forms:

Answer 25

the spinal cord

Question 26

The peripheral nervous system of the fly develops from what cells?

Answer 26

Ectodermal cells called sense organ precursors (SOPs)