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Nervous System

Terms in this set (41)

Glial cells
cells of nervous tissue that are in direct contact with neurons and often surround them
Neurons
highly specialized cells that generate and transmit electric impulses from one part of the body to another
dendrites
receive information from another cell and transmit it to the cell body.
cell body
contains the nucleus, mitochondria, and other organelles typical of the eukaryotic cell
axons
conducts messages away from the cell body
Sensory neurons
have a long dendrite and short axon, and carry messages from sensory receptors to the CNS
Motor neurons
have a short dendrite and long axons and transmit messages from the CNS to the muscles (or to glands)
CNS
The division of the nervous system that includes the brain and spinal cord.
Interneurons
found only in the CNS and connect neuron to neuron
myelin sheath
layers of specialized glial cells, called Schwann cells, that coat the axons of many neurons
Schwann cells
serve as supportive, nutritive and service facilities for neurons
Action potential
A reversal of the electrical potential in the plasma membrane of a neuron that occurs when a nerve cell is stimulated; caused by rapid changes in membrane permeability to sodium and potassium.
Acetylcholine
A chemical released at neuromuscular junctions that binds to receptors on the surface of the plasma membrane of muscle cells, causing an electrical impulse to be transmitted. The impulse ultimately leads to muscle contraction.
Resting potential
results from differences between sodium and potassium positively charged ions and negatively charged ions in the cytoplasm.
Synapse
The junction between a nerve cell and another cell
neurotransmitters
Chemicals released from the tip of an axon into the synaptic cleft when a nerve impulse arrives; may stimulate or inhibit the next neuron
norepinephrine
A hormone produced in the adrenal medulla and secreted under stress; contributes to the "flight or fight" response
radial symmetry
creatures with this, lack a head. Although lacking a brain or either nervous system (CNS or PNS) nerve nets are capable of some complex behavior.
Peripheral Nervous System
The division of the nervous system that connects the central nervous system to other parts of the body. Components of the nervous system that transmit messages to the central nervous system.
ganglia
Clusters of neurons that receive and process signals; found in fatworms and earthworms.
afferent
pathways that provide input from the body into the CNS. (sensory)
efferent
pathways that carry signals to muscles and glands. (motor)
Somatic Nervous System
The portion of the peripheral nervous system consisting of the motor neuron pathways that innervate skeletal muscles.
Autonomic Nervous System
is that part of PNS consisting of motor neurons that control internal organs. It has two subsystems.
Sympathetic Nervous System
The subdivision of the autonomic nervous system that dominates in stressful or emergency situations and prepares the body for strenuous physical activity, e.g., causing the heart to beat faster. involved in fight or flight response
Parasympathetic Nervous System
The subdivision of the autonomic nervous system that reverses the effects of the sympathetic nervous system. Part of the autonomic nervous system that controls heartbeat, respiration and other vital functions. involved in relaxation
Cerebrum
The part of the forebrain that includes the cerebral cortex; the largest part of the human brain. (seat of consciousness)
Cerebellum
That part of the brain concerned with fine motor coordination and body movement, posture, and balance; is part of the hindbrain and is attached to the rear portion of the brain stem.
Medulla Oblongata
The region of the brain that, with the pons, makes up the hindbrain; controls heart rate, constriction and dilation of blood vessels, respiration, and digestion. (part of the unconscious brain)
hypothalamus
regulates homeostasis. It has regulatory areas for thirst, hunger, body temperature, water balance, and blood pressure, and links the Nervous System to the Endocrine System
midbrain
A network of neurons that connects with the forebrain and relays sensory signals to other integrating centers
pons
The region that, with the medulla oblongata, makes up the hindbrain, which controls heart rate, constriction and dilation of blood vessels, respiration, and digestion.
thalamus
The brain region that serves as a switching center for sensory signals passing from the brain stem to other brain regions; part of the diencephalon
corpus callosum
Tightly bundled nerve fibers that connect the right and left hemispheres of the cerebrum.
pituitary
or hypophysis, is an endocrine gland about the size of a pea. A protrusion off the bottom of the hypothalamus at the base of the brain, and rests in a small, bony cavity (sella turcica)
forebrain
consists of the diencephalon and cerebrum
cerebral cortex
The outer layer of gray matter in the cerebrum; consists mainly of neuronal cell bodies and dendrites in humans; associated with higher functions, including language and abstract thought.
central sulcus
A fold in the cerebral cortex of brains in vertebrates. A prominent landmark of the brain, separating the parietal lobe from the frontal lobe and the primary motor cortex from the primary somatosensory cortex
Diencephalon
Part of the forebrain; consists of the thalamus and hypothalamus.
gray matter
is a major component of the central nervous system, consisting of neuronal cell bodies which actually has a grey-brown color.
white matter
one of the two components of the central nervous system and consists mostly of myelinated axons, appears pinkish white to the naked eye because myelin is composed largely of lipid tissue veined with capillaries
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