Anatomy of Developing Nervous System Flashcards
What are the 3 primary tissues (or “germ layers”) shared by embryos of animals?
1) Ectoderm
2) Mesoderm
3) Endoderm
What is Gastrulation?
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)
What is Neurulation?
the formation of the neural tube via rapid growth rate, cell movement, and changes to cell shape
What does the ectoderm eventually form?
The ectodermal cells become the epidermis (skin) and nervous system (neuroectoderm)
What does the mesoderm eventually become?
Muscles and skeleton
What does the endoderm become?
the gut and associated organs
What is the “Anterior” side of an embryo & what is also known as?
aka rostral or “pertaining to a break”
end of embryo where head forms
Which direction is Posterior and what is another term for it in reference to an embryo?
aka caudal = “pertaining to a tail”
opposite end of the head of the embryo
What are the 2 types of Neurulation?
1) Primary
2) Secondary
What is Primary Neurulation?
when the neural plate roles up to form the neural tube
What is Secondary Neurulation?
process of forming the neural tube involving hollowing out an initially solid rod of tissue
What is a Blastula?
animal embryo at the early stage of development when it is a hollow ball of cells
What is a Blastocyst?
embryo that forms after the sperm fertilizes an egg prior to gastrulation
What can result as a failure of neurulation?
Neural tube defects
What are the 2 most common neural tube defects and what is the prevelance?
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
What is a Stem cell?
unspecialized cell that can divide repeatedly to regenerate itself and give rise to more specialized cells (such as neurons or glia)
What are parts of the Central Nervous System (CNS) & what are its main functions?
- Includes the Brain, Spinal Cord, & Retina
- Responsible for information processing and memory storage
What is the Peripheral Nervous System (PNS) and what are its main functions?
- 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
Bipolar Neuron
Neuron with 2 projections emanating from the cell body or soma
Multipolar Neuron
Type of neuron that has a single axon and several dentrites extending from its body
In vertebrates, where does the Peripheral Nervous System originate from?
The Neural crest which originates from the Neuroectoderm germ layer
What are Autonomic Neurons?
Neurons in the PNS that control body functions below level of consciousness such as:
- respiration
- heart rate
- digestion
What are Schwann Cells?
glial cells of the PNS that produce myelin sheath around axons
The anterior part of the neural tube forms:
1) the forebrain
2) the midbrain
3) the hindbrain
