Lecture Exam 1 Flashcards
(17 cards)
What is a nucleus in the nervous system?
A group of neuron cell bodies (somata) within the CNS.
What is a ganglion?
A group of neuron cell bodies outside the CNS (in the PNS).
What are dendrites?
Short, branched processes that receive signals from other neurons and send them toward the cell body.
What is an axon?
A single, long process that conducts electrical impulses away from the cell body toward effector cells or other neurons.
What is a synapse?
The junction between the axon terminal and its target (another neuron or an effector cell).
What role do neurotransmitters play at the synapse?
They transmit the signal to the adjacent cell.
What is the myelin sheath?
An insulation around many axons that speeds up the conduction of electrical impulses.
Who creates the myelin sheath in the CNS?
Oligodendrocytes.
Who forms the myelin sheath in the PNS?
Schwann cells (neurolemmocytes) wrap around the axon.
What are nodes of Ranvier?
Gaps left by Schwann cells that help in the rapid transmission of signals.
What are multipolar neurons?
Neurons that have three or more processes (one axon and multiple dendrites).
What are bipolar neurons?
Neurons that have one axon and one dendrite, located opposite each other.
Where are bipolar neurons found?
In the retina and olfactory epithelium.
What are unipolar neurons?
Neurons that have a single process that divides into two branches—one leading to sensory receptors and the other to the CNS.
What are sensory (afferent) neurons?
Neurons that transmit impulses from sensory receptors to the CNS.
What are motor (efferent) neurons?
Neurons that transmit impulses from the CNS to effectors such as muscles or glands.
What are interneurons?
Neurons that act as intermediaries between sensory and motor neurons, processing and transmitting information within the CNS.
