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Anatomy Exam 3
Anatomy
Question | Answer |
---|---|
Nerve | A cordlike organ of the peripheral nervous system. A bundle of nerve fibers (axons) wrapped in fibrous connective tissue. |
Nerve function | Emerges from the CNS through foramina of the skull and vertebral column and carry signals to and from other organs of the body. |
The meninges | Dura mater, Archanoid mater, Pia mater |
Central Nervous System (CNS) | Brain and spinal cord, which are enclosed and protected by the cranium and vertebral column |
Peripheral Nervous System (PNS) | Composed of nerves and ganglia |
Sensory neurons | Specialized to detect stimuli such as light, heat, pressure, and chemicals, and transmit information about them to the CNS. |
Afferent | Towards the CNS |
Efferent | Away from the CNS |
Interneurons | lie entirely within the CNS. They process, store,and retrieve information and "make decisions" that determine how the body responds to stimuli. |
Motor neurons | Sends signals predominantly from the CNS to the muscle and gland cells, the effectors. |
Soma | control center of the neuron |
Dentrites | primary site for receiving signals from other neurons. |
Multipolar neuron | It has one axon and multiple dendrites, it is the most common and mostly in the brain and spinal cord. |
Bipolar neuron | It has one axon and one dendrite. Located in eyes and ears. |
Unipolar neuron | Its a single process leading away from the soma. It carries sensory signals from skin and organs to spinal cord |
Glial cells | Protect the neurons and help them function. They bind neurons together and provide a supportive framework for the nervous tissue. |
Oligodendrocytes | Spirals like electrical tape forming myelin in brain and spinal cord. |
Ependymal cells | Line cavities of bain and spinal cord; secrete and circulate cerebrospinal fluid (CSF) |
Microglia | Phagocytize and destroy microorganisms, foreign matter, and dead nervous tissue. |
Astrocytes | Most abundant glial cell in CNS, they cover the entire brain surface and most nonsynaptic regions of the neurons in the gray matter of the CNS, and they induce the blood brain barrier. |
Schwann cells | Produce a myelin sheath similar to the ones produced by oligodendrocytes in CNS and assist in the regeneration of damaged fibers |
Satellite cells | Surround somas of neurons in the ganglia; provide electrical insulation and regulate chemical environment of neurons. |
Action potential | dramatic change produced by voltage-gated ion channels in the plasma membrane. |
Local potential | Short-range change in voltage |
Action potential characteristics | Irreversible; goes to completion once begins Self-propagating; has effects a great distance from one point to another Nondecremental; signal maintains same strength regardless of distance |
Local potential characteristics | Reversible; returns to RMP if stimulation ceases before threshold is reached Local; has effects for only a short distance from point of origin Decremental; signal grows weaker with distance |
Neurotransmitter | A chemical released at the distal end of an axon that stimulates an adjacent cell |
Synapse | A junction at the end of an axon where it stimulates another cell. |
Tympanic membrane | The eardrum |
Dorsal root | Carries afferent (sensory) nerve fibers |
Excitatory postsynaptic potential (EPSP) | Any voltage change in the direction of threshold that makes a neuron more likely to fire |
Inhibitory postsynaptic potential (IPSP) | Any voltage change away from threshold that makes a neuron less likely to fire |
Auricle | outer portion of the ear. |