Chapter 9 - Nervous System Flashcards
adrenergic fiber
a neuron for which the neurotransmitter is either adrenaline, noradrenaline or dopamine
body’s control network
Control of the body’s billions of cells is accomplished in part by two body-wide communication systems: the nervous system and the endocrine system. Both systems transmit information from one part of the body to another, but they do it in different ways. The nervous system transmits information very rapidly by nerve impulses conducted from one body area to another. The endocrine system transmits information more slowly by chemicals secreted by ductless glands into the bloodstream and then circulated to other parts of the body.
autonomic nervous system
A subdivision of the peripheral nervous system; it consists of structures that regulate the body’s automatic or involuntary functions (for example, heart rate, contractions of the stomach and intestines, and secretion of chemical compounds by glands).
glia (adjective: glial)
Non-neuronal cells (i.e. not nerves) of the brain and nervous system. There are a variety of subtypes of glial cells, including astrocytes, oligodendrocytes, and microglia, each of which is specialized for a particular function. They are also called neuroglia.
structure of a neuron
Each neuron consists of three parts: a main part called the neuron cell body, one or more branching projections called dendrites, and one elongated projection known as an axon.
Schwann cell
a variety of glial cells that keep peripheral nerve fibers (both myelinated and unmyelinated) alive
Nodes of Ranvier
gaps between adjacent Schwann cells
neurilemma
the outer wrapped layer of a Schwann cell
sensory neuron
carry impulses to the spinal cord and brain from all parts of the body. Sensory neurons are also called afferent neurons.
motor neurons
carry impulses in the opposite direction—away from the brain and spinal cord. They do not conduct impulses to all parts of the body—only to two kinds of tissue—muscle and glandular epithelial tissue. Motor neurons are also called efferent neurons.
interneurons
conduct impulses from sensory neurons to motor neurons. They also often connect with each other to form complex, central networks of nerve fibers. Interneurons are sometimes called central or connecting neurons.
glioma
a common type of brain tumor that grows out of glial cells
astrocyte
star-shaped glial cells that have a number of functions, including support of the blood-brain barrier, provision of nutrients to neurons, repair to nervous tissue following injury, and facilitation of neurotransmission
blood-brain barrier (BBB)
A crucial immunological feature of the human central nervous system (CNS). Composed of many cell types, the BBB is both a structural and functional roadblock to microorganisms, such as bacteria, fungi, viruses or parasites, that may be circulating in the bloodstream
microglia
A type of glial cell that is smaller than astrocytes; they usually remain stationary, but in inflamed or degenerating brain tissue, they enlarge, move about, and act as microbe-eating scavengers. They surround the microbes, draw them into their cytoplasm, and digest them. They likewise help clean up cell damage resulting from injury or disease.
oligodendrocyte
also called oligodendroglia; a type of neuroglia whose main functions are to provide support and insulation to axons in the central nervous system
nerve
A group of peripheral nerve fibers (axons) bundled together like the strands of a cable. Peripheral nerve fibers usually have a myelin sheath. Because myelin is white, peripheral nerves often look white.
endoneurium
a thin wrapping of fibrous connective tissue that surrounds the axon of a nerve
neuron pathway
the routes traveled by nerve impulses
perineurium
a protective sheath that surrounds a nerve fascicle
epineurium
A tough, fibrous sheath that covers a whole nerve
tract
1a: a system of body parts or organs that act together to perform some function (e.g. the digestive tract)
1b: a bundle of nerve fibers having a common origin, termination, and function
2: an area either large or small: such as an indefinite stretch of land or a defined area of land
3: extent or lapse of time
white matter
neural tissue especially of the brain and spinal cord that consists largely of myelinated nerve fibers bundled into tracts, has a whitish color, and typically underlies the cortical gray matter
gray matter
neural tissue especially of the brain and spinal cord that contains nerve-cell bodies as well as nerve fibers and has a brownish-gray color
underlie
(1) to lie or be situated under
(2) to be at the basis of: form the foundation of
maul
(noun) a heavy often wooden-headed hammer used especially for driving wedges
(verb) beat or bruise, mangle, handle roughly
mangle
(1) to injure with deep disfiguring wounds by cutting, tearing, or crushing
(2) to spoil, injure, or make incoherent especially through ineptitude
inept
(1) generally incompetent
(2) lacking in fitness or aptitude (e.g. inept in sports)
(3) not suitable to the time, place, or occasion: inappropriate often to an absurd degree
(4) lacking sense or reason : FOOLISH
reflex arc
A neural pathway that controls a reflex. In vertebrates, most sensory neurons do not pass directly into the brain, but synapse in the spinal cord. This allows for faster reflex actions to occur by activating spinal motor neurons without the delay of routing signals through the brain. The brain will receive the sensory input while the reflex is being carried out and the analysis of the signal takes place after the reflex action.
receptor
the beginnings of dendrites of sensory neurons; it receives stimuli
reflex (anatomy)
an action that is performed as a response to a stimulus and without conscious thought
synapse
A small gap at the end of a neuron that allows a signal (neurotransmitter) to pass from one neuron to the next. Synapses are found where nerve cells connect with other nerve cells.
Synapses are composed of three main parts:
The presynaptic ending that contains neurotransmitters
The synaptic cleft between the two nerve cells
The postsynaptic ending that contains receptor sites