Download Lecture #10

Lecture #10: Development of the Nervous System
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What is the difference between the CNS and the PNS?
What are the main functions of the nervous system?
What are the neurons and how do they communicate with each other?
What are neuroglia?
How many neurons are there in the human brain? How many glial cells
are there in the brain?
6. How many connections does each neuron have?
7. In the 5th/6th week of development, the neural groove closes to become
the neural tube. At the 7th/8th week of development, the anterior portion
of this tube becomes the what? What does the posterior portion of this
tube becomes what?
8. An open canal persists and then forms which portion of the CNS?
9. What do the cells of the neural crest give rise to?
10. How do neurons communicate with each other?
11. What is the function of the spongioblast?
1. The Central Nervous System (CNS) is made up by the brain and the spinal
cord. It serves as the main communication and control center of the
nervous system. The Peripheral Nervous System (PNS) is made up of 12
cranial nerves and 31 spinal nerves. This system is further divided into the
autonomic and somatic nervous system. The autonomic system controls
involuntary actions (ie motor and sensory for digestion, reflexes, balance)
and the somatic controls voluntary actions (motor and sensory for all
actions you decide – playing basketball, walking, studying – yeah right).
2. a. communication between internal and external environments by
regulating motor activity, sensory perception, special senses, balance and
control)
b. regulation of intellect, behavior and general interpretation
c. regulation of metabolism
d. regulation of homeostasis
e. regulation of endocrine function
f. regulation of immune function
3. The neuron is the basic unit cell of the nervous system. They are
responsible for relaying messages throughout the body. They
communicate via neurotransmitters (ie dopamine, epinephrine) and
neurohormones (ie. GnRH)
4. Neuroglia are the “support cells” which nourish and create products (ie
myelin) for the neurons. These include astrocytes which are serve as the
metabolism center (they feed the cells) for neurons and the oligodendrites
which produce myelin.
5. There are 1012 neurons in the adult brain. There are 10 to 15 times more
glial cells than neurons.
6. Each neuron has 10,000 connections.
7. The anterior portion becomes the brain and the posterior section becomes
the spinal cord.
8. The open canal persists and forms the central canal of the spinal cord and
the ventricles of the brain.
9. The cells of the neural crest give rise to the spinal ganglia. The spinal
ganglia is responsible for sympathetic nervous system functioning (“fight
or flight response).
10. Neurons communicate via neurotransmitters, for example serotonin,
dopamine, Ach. A neuron will release neurotransmitters from its dendrite
which will travel across the synapse to another neuron’s axon. Once the
neurotransmitter is received, this will stimulate an electrical impulse in the
downstream neuron. This cell will now pass on the message to other
neurons.
11. Spongioblasts are cells found in developing nervous system: gives
rise to astrocytes and oligodendrocytes.