CNS Flashcards
(26 cards)
What is organogenesis?
The development of the specific tissues and organs of the body.
Organs that perform related functions are grouped into systems, with 11 organ systems in total.
What composes the Central Nervous System (CNS)?
The brain and spinal cord.
Neurons are the basic functional units of the CNS.
What are neurons specialized to do?
Receive stimuli from the environment and transmit impulses.
Impulses are interpreted in the spinal cord and brain, then transmitted to effector organs.
What are the types of connective tissue cells in the CNS?
Gliocytes, including oligodendrocytes, astrocytes, microgliocytes, and ependymal cells.
What are the main components of a neuron?
- Nerve cell body (contains cytoplasm and nucleus)
- Axon (conducts impulses away from the cell body)
- Dendrites (receive stimuli and convert them into impulses)
How are neurons classified based on the number of dendrites?
- Unipolar neuron: one process (axon only)
- Bipolar neuron: two processes (axon & dendrite)
- Multipolar neuron: many processes (one axon & many dendrites)
What does the enlarged cranial portion of the neural tube become?
The brain.
What does the slender middle and caudal portions of the neural tube become?
The spinal cord.
What do neural crest cells give rise to?
- Neurons of the PNS
- Neurolemocytes (Schwann cells)
- Adrenal medulla cells
- Melanocytes of skin
- Various structures in the face
What is the germinal layer of the neural tube wall composed of?
Neuroepithelial cells that line the central canal and become ependymal cells.
What is the mantle layer of the neural tube wall?
The middle layer, formed by neuroblasts and glioblasts, which becomes the gray matter of the CNS.
What is contained in the marginal layer of the neural tube wall?
Axons of neurons and some gliocytes; becomes the white matter of the CNS.
What divides the lateral wall of the neural tube into alar and basal plates?
The sulcus limitans.
What are the three primary brain vesicles formed from the cranial end of the neural tube?
- Prosencephalon (forebrain)
- Mesencephalon (midbrain)
- Rhombencephalon (hindbrain)
What is the midbrain flexure?
A flexure that occurs at the level of the midbrain, concave ventrally.
By what hour of incubation do the three brain vesicles divide into four?
By 38 hours of incubation.
What are the two parts into which the rhombencephalon divides?
- Metencephalon
- Myelencephalon
What happens to the optic vesicles during brain development?
They form from the evagination of the lateral walls of the prosencephalon.
What is hydrocephalus?
Accumulation of excessive cerebrospinal fluid in the cranial cavity.
What is myelodysplasia?
A general term for a malformation of the spinal cord.
What is myeloschisis?
A cleft in the neural tube due to failure to close during neurulation.
What is spina bifida?
The failure of vertebral arches to close dorsal to the spinal cord.
Fill in the blank: The spinal cord is divided into _____ and _____ plates.
alar and basal
True or False: Neurons are capable of cell division.
False.
