Term
| effectors of the nervous system |
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Definition
| the nervous system dictates responses by activating effector organs such as our muscles and glands |
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Term
| CNS components and functions |
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Definition
| The CNS consists of the brain and spinal cord. It is the integrating and command center for the nervous system. It receives incoming sensory signals, interprets these signals, and dictates motor responses. |
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Term
| PNS components and functions |
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Definition
| The PNS is outside the CNS. It consists of nerves that extend from the brain to the spinal cord. Cranial nerves carry signals too and from the brain. Spinal nerves carry signals to and from the spinal cord. There is also ganglia in the PNS. THese are areas where cell bodies of neurons are clustered |
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Definition
| or SENSORY signals. They are picked up by sensory receptors located throughout the body and carried by nerve fibers of PNS to CNS |
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Definition
| or MOTOR signals. They are signals carried away from CNS by nerve fibers of PNS to innervate muscles and glands, causing these organs to either contract or to secrete. |
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Definition
| both sensory inputs and motor outputs are further divided according to the body region they serve: the somatic body region and visceral body region. |
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Definition
| consists of structures external to the ventral body cavity, in other words the structures of the outer tube (skin, skeletal musculature, bones) |
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Definition
| mostly contains the viscera within the ventral body cavity, which means the structures of the body's inner tube (digestive tube, lungs, heart, bladder) |
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Definition
| The somatic body region and visceral body region further divide into four main subdivisions: Somatic sensory, visceral sensory, somatic motor, visceral motor. |
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Definition
| senses spread through out the outer tube of body. These include areas with the skin and body wall such as touch, pain, vibration, and temperature. |
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Definition
| informs you of the position and movement of your body in space giving you "body sense". |
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Term
| The special somatic senses |
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Definition
| are the somatic senses whose receptors are confined to small areas rather than spread out throughout the body. Most are confined in the head, including hearing and balance, or equilibrium. |
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Definition
| include stretch pain and temperature which can be felt widely in the digestive and urinary tracts, reproductive organs and other viscera. Sensations such as hunger and nausea. |
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Definition
| Taste and smell are considered special visceral sensory senses. These senses, also referred to as the chemical senses, have their sensory receptors localized to the tongue and nasal cavity |
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Definition
| part of the PNS stimulates contraction of skeletal muscles in the body. Because we have voluntary control over the contraction of our skeletal muscles, the somatic motor system is often called the VOLUNTARY nervous system |
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Definition
| part of the PNS regulates the contraction of smooth and cardiac muscles and secretion by the body's many glands. They make up the autonomic nervous system, which controls the function of the visceral organs. INVOLUNTARY nervous system |
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Term
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Definition
| the human body contains billions of neurons, or nerve cells, which are the basic structural units of nervous system.They are highly specialized cells which conduct electrical signals from one part of the body to the other. These signals are transmitted along the plasma membrane in the form of nerve impulses, or action potentials. |
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Term
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Definition
| also called soma. all consist of a signal nucleus surrounded by cytoplasm. |
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Term
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Definition
| processes extend from the cell bodies of all neurons. These processes are of two types: dendrites and axons. |
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Term
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Definition
| conduct electrical signals toward the cell body |
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Term
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Definition
| a neuron has only one axon which arises from a cone shaped region of the cell body called the axon hillock transmit nerve impulses away from their cell body |
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Term
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Definition
| the site at which neurons communicate is called synapse. Most synapses in nervous system transmit information through chemical messengers. However, some neurons in certain areas of the CNS transmit signals electrically through gap junctions. Presynaptic neurons conduct signals toward a synapse. Postsynaptic neurons carry signals away from synapse. |
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Term
| Structural Classification |
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Definition
| Neurons are grouped structurally according to the number of processes that extend from the cell body: Multipolar, Bipolar, Unipolar |
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Term
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Definition
| Most are multipolar; that is they have more than two processes. Usually, multipolar neurons have numerous dendrites and a single axon. |
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Term
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Definition
| have two processes that extend from opposite sides of the cell body. These very rare neurons occur in some of the special sensory organs (inner ear, olfactory epithelium of nose, retina of the eye) |
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Term
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Definition
| have short, single process that emerges from the cell body and divides like an inverted T into two long branches. Most unipolar neurons start out as bipolar whose two processes fuse together near the cell body during development. They are found in sensory ganglia in PNS. The short, single processes near the neuron cell body divide into two processes. One branch runs centrally into the CNS called the central process where as the other extends to the receptors called the peripheral process |
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Term
| Functional classification of neurons |
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Definition
| neurons are grouped functionally according to the direction the nerve impulse travels relative to the CNS. There are sensory neurons, motor neurons, and interneurons |
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Term
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Definition
| or afferent neurons, make up sensory division of PNS. They transmit impulses toward the CNS from sensory receptors in the PNS. The cell bodies are in ganglia outside the CNS. The peripheral process extends from a sensory receptor; the central process terminates in the CNS. |
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Definition
| efferent neurons, make up the motor division of the PNS. THese neurons carry impulses away from the CNS to effector organs. Motor neurons are multipolar, and their cell bodies are located in the CNS. |
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Definition
| or association neurons, lie between motor and sensory neurons. They are confined entirely to the CNS. |
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Term
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Definition
| is neuroglia in the CNS. They have fewer branches than the astrocytes. They line up in small groups and wrap their cell processes around the thicker axons in the CNS, producing insulating coverings called myelin sheaths |
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Definition
| one of the two neuroglia in the PNS. Schwann cells surround all axons in the PNS and form myelin sheaths around many of these axons. |
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Term
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Definition
| are produced by oligodendrocytes in the CNS and Schwann cells in the PNS. These sheaths are segmented structures that are composed of the lipoprotein myelin and surround the thicker axons of the body. |
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Definition
| Each segment of myelin consists of the plasma membrane of a supporting cell rolled in concentric layers around the axon. |
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Term
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Definition
| cluster of axons in the PNS |
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Term
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Definition
| cluster of axons in the CNS |
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Term
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Definition
| is a gray colored zone that surrounds the hollow central cavity of the CNS. In the spinal chord it is the butterfly shaped region in which the dorsal half contains cell bodies of interneurons and the ventral half contains cell bodies of motor neurons. |
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Term
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Definition
| external to gray matter is the white matter, which contains no neuron cell bodies but millions of axons. Its white color comes from the myelin sheaths around many of the axons. It consists of axons running between different parts of the CNS. |
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Term
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Definition
| a nerve is a cable like organ in the NS. Each nerve consists of many axons arranged in parallel bundles and enclosed by successive wrappings of CT. Within a nerve each axon is surrounded by Schwann cells. Endoneurium is the CT surrounding the Schwann cells. Perineurium is CT surrounding the fascicles. The Epineurium is the CT surrounding an entire nerve. |
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Term
| 5 components of reflex arc |
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Definition
1. The receptor is the site where the stimulus acts. Receptors are located at the terminal end of the peripheral process of a sensory neuron.
2. the sensory neuron transmits afferent impulses to the CNS
3. the integration center consists of one or more synapses in the gray matter of the CNS.
4. motor neuron conducts efferent impulses from the integration center to an effector
5. the effector is the muscle or gland cell that responds to the efferent impulses by contracting or secreting. |
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Term
| 5 components of reflex arc |
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Definition
1. The receptor is the site where the stimulus acts. Receptors are located at the terminal end of the peripheral process of a sensory neuron.
2. the sensory neuron transmits afferent impulses to the CNS
3. the integration center consists of one or more synapses in the gray matter of the CNS.
4. motor neuron conducts efferent impulses from the integration center to an effector
5. the effector is the muscle or gland cell that responds to the efferent impulses by contracting or secreting. |
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