Module 13: Nervous System Flashcards
What are Oligdendrocytes found and what do they form?
Form myelin sheath in CNS
Where are Astrocytes found and what do they form?
Found in brain tissue in CNS; form blood-brain barrier.
Where are Schwann cells found and what do they form?
Form myelin sheath in peripheral nervous system
What are Neuroglia?
Cells in the nervous system that support neurons but do not conduct impulses
What is the role of Microglia?
Perform phagocytosis
What is the role of Sensory (Afferent) Neurons?
Detect stimuli such as touch, pressure, heat, cold, or chemicals and then transmit information about the stimuli to the CNS
What is the role of Interneurons?
Connect incoming sensory pathways with the outgoing motor pathways. Found only in CNS.
What is the role of Motor Neurons?
Relay messages from the brain (which the brain emits in response to stimuli) to the muscle or gland cells.
Describe the part of the Neuron: Cell Body (Soma)
The control center of the neuron and contains the nucleus
Describe the part of the Neuron: Dendrites
Receive signals from other neurons and conduct the information to the cell body. Looks like the bare branches of a tree.
Describe the part of the Neuron: Axon
Carries nerve signals away from the cell body
Describe the part of the Neuron: Myelin Sheath
Insulates the axon. Made mostly of lipid in the PNS Schwann cells form the myelin sheath but in the CNS oligodendrocytes assume this role.
Describe the part of the Neuron: Nodes of Ranvier
Evenly spaced gas in the myelin sheath
Describe the part of the Neuron: Synaptic Knob
Vesicles containing a neurotransmitter
What do Ascending spinal tracts convey?
Sensory signals
What do Descending spinal tracts conduct?
Motor Impulses
What is the Cauda Equina?
A bundle of nerve roots extending from the end of the spinal cord
What are the 3 layers of the meninges from the inside out?
Pia, Arachnoid, and Dura
What are Autonomic (Visceral) Reflexes?
Involve secretion from glands or the contraction of smooth muscle. These reflexes are governed by autonomic neurons.
What are Somatic Reflexes?
Involve contraction of a skeletal muscle after being stimulated by a somatic motor neuron.
What are the 4 steps of Somatic Reflexes?
- Somatic receptors detect a sensation 2. Sensory nerve fibers send a signal 3. The impulse immediately passes to a motor neuron. 4. The motor neuron initiates an impulse back to the muscle causing it to contract.
Where can you find Ependymal cells?
Line spinal cord and cavities
of the brain
What is the Blood Brain Barrier?
Formed as astrocytes wrap around capillaries
Protects brain from foreign substances
What is Membrane Potential?
When ions with opposite electrical charges are separated `by a membrane
