A&P 1: Ch 27 Nervous Tissue and Nerves
Sensory (afferent) Neuron
Conducts impulses from receptors in peripheral body parts into the brain or spinal cord
Motor (efferent) Neuron
Conducts impulses from the brain or spinal cord out to muscles and glands
What is the shape of ependymal cell?
Cuboidal cells lining cavities of the brain and spinal cord.
Neuron process with many branches that conducts an action potential (impulse toward the cell body)
Dendrite
Bipolar Neuron
One axon and one dendrite
What is the function of microglia?
- Structural support - Phagocytosis of microorganisms and damaged tissues
The PNS contains a. 12 pairs of cranial nerves only b. 31 pairs of spinal nerves only c. 12 pairs of cranial nerves and 31 pairs of spinal nerves d. 43 pairs of spinal nerves
12 pairs of cranial nerves and 31 pairs of spinal nerves
Unipolar Neuron
A single process that divides into two branches and functions as an axon
Star-shaped neuroglia between neurons and blood vessels
Astrocyte
What type of cells are found in the CNS?
Astrocytes, microglia, oligodendrocytes, ependyma
Nerve-fiber arising from a slight elevation of the cell body that conducts an action potential (impulse) away from the cell body
Axon
Myelinated Axon
Axon with myelin sheath around it
Unmyelinated Axon
Axon without myelin sheath around it
Branch of an axon
Collateral
What does the axon (nerve fiber) do?
Conduct impulses away from the cell body
What do dendrites do?
Conduct impulses toward the cell body
Structure capable of responding to motor impulse
Effector
Cells that line cavities of the brain and secrete cerebrospinal fluid
Ependymal cell
True or false: Sensory neurons conduct impulses from the spinal cord to a muscle or a gland
False
What is the function of an oligodendrocyte?
Form myelin sheaths in the brain and spinal cord
Specialized mass of neuron cell bodies outside the brain or spinal cord
Ganglion
Schwann cells a. Are only in the brain b. Are only in the spinal cord c. Are throughout the CNS d. Have a myelin sheath and neurilemma
Have a myelin sheath and neurilemma
Substance of Schwann cell composed of lipoprotein that insulates axons and increases impulse speed
Myelin
Transmits impulse from sensory to motor neuron within central nervous system
Interneuron
A multipolar neuron contains a. One dendrite and many axons b. Many dendrites and one axon c. One dendrite and one axon d. A single process with the dendrite and axon
Many dendrites and one axon
Phagocytic neuroglia
Microglia
What is the function of an astrocyte? (5)
Most abundant type- - Provide structural support - Communicate with other neurons - Remove excess ions and neurotransmitters - Transport of substances between blood vessels and neurons -Form scar tissue to replace damaged neurons
Multipolar, Bipolar, or Unipolar? Sensory neuron
Most unipolar; some bipolar
Transmits impulse out of the brain or spinal cord to effectors (muscles and glands)
Motor (efferent) neuron
A _____________ neuron is the most common structural neuron in the brain and spinal cord a. Multipolar b. Tripolar c. Bipolar d. Unipolar
Multipolar
Multipolar, Bipolar, or Unipolar? Interneuron
Multipolar
Multipolar, Bipolar, or Unipolar? Motor neuron
Multipolar
Sheath of Schwann cell containing cytoplasm and nucleus that encloses myelin
Neurilemma
Network of threadlike structures within cell body and extending into axon
Neurofibrils
Corresponds to rough endoplasmic reticulum
Nissl bodies
The cell body of a neuron contains the a. Nucleus b. Dendrites c. Axon d. Neuroglia
Nucleus
Myelin-forming neuroglia in brain and spinal cord
Oligodendrocyte
Neuroglia that produce myelin insulation in the CNS are a. Microglia b. Astrocytes c. Ependymal cells d. Oligodendrocytes
Oligodendrocytes
Multipolar neuron
One axon and multiple dendrites
What is the axon hillock?
Origin region of axon
What types of cells are found in the PNS (Peripheral nerves)?
Schwann cells & satellite cells
What is the function of ependymal cell?
Secrete and assist in circulation of cerebrospinal fluid
Transmits impulse into brain or spinal cord from receptors
Sensory (afferent) neuron
What is the shape of an oligodendrocyte?
Shaped like astrocytes, but with fewer cellular processes
What is the shape of microglia?
Small cells with slender cellular processes
What is the shape of an astrocyte?
Star-shapes cells contacting neurons and blood vessles
Where does nervous tissue occur?
The brain, spinal cord, and peripheral nerves
Possesses a single process from the cell body
Unipolar Neuron
What do Schwann cells do?
They are cells that wrap tightly around the axons of peripheral neurons; speed up neurotransmission
What do Satellite cells do?
They are flattened cells that surround cell bodies of neurons in ganglia; they support ganglia
Interneuron
Transmits impulses between neurons in the brain and spinal cord
True or False: Astrocytes have contacts between blood vessels and neurons in the CNS
True
