Term
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Definition
| Chemical transmitter substance released by some nerve endings. |
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Term
| Acetylcholinesterase (AChE) |
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Definition
| Enzyme present at the neuromuscular junction and synapses that degrades ACh & terminates its action. |
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Term
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Definition
| forms a loose brain covering; the middle layer of the 3 meninges. |
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Term
| Autonomic Nervous System (ANS) |
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Definition
| Efferent division of the peripheral nervous system that innervates cardiac & smooth muscles & glands; also called involuntary or visceral nervous system |
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Term
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Definition
| Neuron process that carries impulses away from the nerve cell body; efferent process; the conducting portion of a nerve cell. |
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Term
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Definition
| Consists of a spherical nucleus with a conspicuous nucleolus surrounded by cytoplasm; also called perikaryon or soma; major bosynthetic center of a neuron. |
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Term
| Central Nervous System (CNS) |
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Definition
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Term
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Definition
Controls movement and balance. Outer cortex of gray matter contains pukinje cell layer between molecular & granular layers.
Brain region most involved in producing smooth, coordinated skeletal muscle activity. |
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Term
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Definition
| Form the superior part of the brain; account for 83% of total brain mass. |
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Term
| Cerebrospinal Fluid (CSF) |
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Definition
| Plasmalike fluid that fills the cavaties of the CNS & surrounds the CNS externally; protects the brain & spinal cord. |
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Term
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Definition
| The cerebral hemispheres & structures of the diencephalon. |
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Term
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Definition
| Branching neuron process that serves as a receptive, or input, region; transmits an electrical signal toward the cell body. |
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Term
| Diencephalon (interbrain) |
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Definition
| That part of the forebrain between the cerebral hemispheres & the midbrain including the thalamus, the epithalamus & the hypothalamus. |
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Term
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Definition
| Peripheral collection of cell bodies of first-order afferent neurons whose central axons enter the spinal cord. |
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Term
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Definition
| Outermost & toughest of the 3 membranes (meninges) covering the brain & spinal cord. |
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Term
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Definition
| Region of the diencephalon forming the floor of the 3rd ventricle of the brain. |
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Term
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Definition
| Inferior most part of the brain stem. |
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Term
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Definition
| Protective coverings of the central nervous system; from the most external to the most internal---> dura mater, arachnoid mater, pia mater. |
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Term
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Definition
| Region of the brain stem between the diencephalon & the pons. |
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Term
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Definition
| Portion of the Schwann cell which includes the exposed part of its plasma membrane, the nucleus & most of the cytoplasm. |
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Term
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Definition
Cell of the nervous system specialized to generate & transmit electrical signals (action potentials & graded potentials)
Make up the gray matter of the nervous system; neuron processes running through the CNS form TRACTS of white matter; in the PNS they form the peripheral NERVES. |
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Term
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Definition
Only generated by muscle cells and neurons. Principal means of neural communication. Large, but brief, self-propagating wave of depolarization which neither decreases or increases in strength. It is an ALL OR NOTHING phenomenon.
Several distinct phases: depolarization, repolarization and hyperpolarization. |
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Term
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Definition
| Brief, local changes in membrane potential. They may be hyperpolarizations or depolarizations. They decrease in strength with distance due to "leaky" membranes. Their size varies directly with the strength of stimulus. When strong enough can initiate action potentials. |
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Term
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Definition
| Voltage across the plasma membrane. |
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Term
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Definition
| Chemical messenger released by neurons that may, upon binding to receptors of neurons or effector cells, stimulate or inhibit those neurons or effector cells. |
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Term
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Definition
| The division of the autonomic nervous system that oversees digestion, elimination & glandular function; the resting & digesting subdivision. |
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Term
| Peripheral Nervous System (PNS) |
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Definition
| Portion of the nervous system consisting of nerves & ganglia that lie outside of the brain & spinal cord. |
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Term
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Definition
| Collection of nerve cell bodies outside the CNS. |
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Term
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Definition
| meaning "gentle mother" is composed of delicate connective tissue & is richly invested with tiny blood vessels; clings tightly to the brain. |
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Term
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Definition
| A network of convergin & diverging nerve fibers, blood vessels or lymphatics. |
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Term
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Definition
| The part of the brain stem connecting the medulla with the midbrain, providing linkage between upper & lower levels of the CNS. |
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Term
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Definition
| A type of supporting cell in the PNS; forms myelin sheaths & is vital to periperal nerve fiber regeneration. |
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Term
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Definition
| Division of the PNS that provides the motor innervation of skeletal muscles; also called voluntary nervous system. |
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Term
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Definition
| 31 nerve pairs that arise from the spinal cord. |
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Term
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Definition
| The division of the autonomic nervous system that prepares the body for activity or to cope with some stressor; fight, fright or flight subdivision. |
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Term
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Definition
| Functional junction or point of close contact between two neurons or between a neuron & effector cell. |
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Term
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Definition
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Term
| Why is the nervous system able to serve as a control & communications network? |
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Definition
1. Irritability- refers to the capacity of nerve tissue to react to various chemical stimuli.
2. Conductivity- Refers to the ability of nervous tissue to transmit stimuli from one place to another. |
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Term
| 3 Fundamental Functions of Nervous System |
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Definition
1. Sensory- Receptors in the skin and organs respond by generating nerve impulses.
2. Integrative- The central nervous "sums up" and analyzes input and decides what course to take. It then sends out "orders" in the form of nerve impulses to effectors.
3. Nerve impulses travel to muscles and glands where muscle actions and glandular secretions serve as the responses to stimuli received by receptors. |
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Term
| Neuroglia in CNS (Glial cells) |
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Definition
These cells support, defend & nourish neurons.
4 Types in CNS:
1. Astrocytes- twine around neurons to form a supporting network in the brain and spinal cord. These cells synthesize neurotransmitters and have vascular fee which attach neurons to blood vessels allowing transport between the two.
2. Oligodendrocytes- These cells help to hold nerve fibers together and produce the myelin sheath in the CNS.
3. Microglia- These phagocytic cells engulf microbes and debris in injured areas.
4. Ependymal Cells- These cells line cavities of the brain and spinal cord and aid in production and circulation of the cerbrospinal fluid (CSF). The CSF cushions the brain and spinal cord and cilia beat to aid in its circulation. |
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Term
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Definition
| Schwann cells & satellite cells (control the chemical environment around neurons). |
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Term
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Definition
| dendrites, cell body or perikaryon, axon |
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Term
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Definition
| Phenomenon where information is received through dendrites and transmitted out via axons. |
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Term
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Definition
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Term
| Classification of Neurons by Function |
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Definition
1. Motor neurons (efferent)- These cells transmit impulses away from the brain or spinal cord toward a muscle or gland. The cell bodies are located in the CNS and are most often multipolar.
2. Sensory Neurons (afferent)- These cells carry impulses toward the spinal cord and brain. Their cell bodies are found in ganglia outside the CNS and are typically unipolar.
3. Interneurons (association)- These cells conduct impulses from sensory to motor neurons. Cell bodies are always located in CNS and are multipolar. |
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Term
| Neuron Type According to Direction of Impulse |
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Definition
1. Multipolar- These neurons have one axon and several dendrites. This is the most common type in humans and the major type in the CNS.
Bipolar- Bipolar neurons have one axon and one dendrite and are located in the retina, the inner ear and the olfactory mucosa.
3. Unipolar- Unipolar neurons originated in the embryo as bipolar but the processes become fused for a short distance beyond the perikaryon and then separate into a clearly defined axon and dendrite. Unipolar neurons are found principally in the PNS and are often sensory neurons. |
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Term
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Definition
| Measured as the potential difference between two charges. |
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Term
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Definition
| Flow of electrical charge from one point to another. |
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Term
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Definition
I=V/R
States that current (I) is directly proportional to voltage (V) and inversely proportional to resistence (R) which is basically provided by anything that stops charge flow such as insulation. |
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Term
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Definition
1. Passive or leakage channels are always open
2. Active or gated have protein molecules which change shape. |
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Term
| 2 Types of Gated or Active Ion Channels |
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Definition
1. Chemically gated- open when a neurotransmitter binds
2. Voltage gated- Open when there is a change in voltage. |
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Term
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Definition
| Ions move along chemical gradients from high to low concentration (chemical gradient). Ions also move toward areas of opposite charge in an electrical gradient. Therefore they have this type of gradient. This ion flow is responsible for changes in electricity in neurons. |
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Term
| Resting Membrane Potential |
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Definition
| Refers to a charge difference when a neuron is at rest, the inside of the membrane is negatively charged in comparison with outside. |
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Term
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Definition
Changes in membrane potential serve a signals to integrate, send and receive information. These changes are due to:
1. changes in membrane permeability to ions.
2. alterations of ion concentrations across the membrane. |
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Term
| Membrane Potential Changes |
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Definition
1. Depolarization- the inside of the membrane becomes less negative.
2. Repolarization- the membrane returns to its resting membrane potential.
3. Hyperpolarization- the inside of the membrane becomes more negative than the resting potential. |
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Term
| Nerve Fiber Classification |
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Definition
Group A Fibers- large diameter, myelinated somatic sensory and motor fibers
Group B Fibers- Intermediate diameter, lightly myelinated ANS fibers.
Group C Fibers- smallest diameter, unmyelinated ANS fibers |
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Term
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Definition
| places where nerve impulses are transmitted from one neuron called a presynaptic neuron to another neuron called the postsynaptic neuron. |
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Term
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Definition
Electrical- allow ion flow directly from one neuron to another via protein channels which connect the cytoplasm of adjacent neurons.
Chemical- places where neurotransmitters are released and bound; consist of a synaptic knob, a synaptic cleft & a postsynaptic membrane. |
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Term
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Definition
| Excitatory Postsynaptic Potential |
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Term
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Definition
| Inhibitory Postsynaptic Potential |
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Term
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Definition
| glial cells which form the myelin sheath in the CNS |
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Term
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Definition
| Because of its chemical composition, this insulates the fibers and greatly increases the speed of neurotransmission by neuron fibers. |
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Term
| Neuron Classifications by Structure |
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Definition
Unipolar (pseudounipolar)-one very short process, which divides into peripheral & central processes, extends from the cell body; nearly all neurons that conduct impulses TOWARD the CNS are unipolar.
Bipolar neurons- have 2 processes attached to the cell body; very rare, but typically found only as part of the receptor apparatus of the eye, ear & olfactory mucosa.
Multipolar- have many processes that are all classified as dendrites except for a single axon; most neurons in the brain & spinal cord & those whose axons carry impulses away from the CNS fall into this category. |
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Term
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Definition
| a bundle of neuron fibers or processes wrapped in connective tissue coverings that extends to and/or from the CNS and visceral organs or structures of the body periphery (such as the skeletal muscles, glands & skin). |
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Term
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Definition
| nerves carrying both sensory & motor nerve fibers (all spinal nerves) |
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Term
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Definition
carry only sensory processes and conduct impulses only toward the CNS
includes a few of the cranial nerves |
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Term
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Definition
carrying only motor (efferent) nerve fibers
the ventral roots of the spinal cord |
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Term
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Definition
| the delicate connective tissue sheath surrounding each nerve fiber within a nerve |
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Term
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Definition
| coarser connective tissue surrounding bundles of nerve fibers (fascicles) |
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Term
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Definition
| white, fibrous connective tissue sheath surrounding the fascicles, forming the nerve |
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Term
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Definition
| outermost gray matter of the cerebrum; cell bodies of cerebral neurons involved in specialized functions found here |
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Term
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Definition
| composed of fiber tracts carrying impulses to or from the cortex |
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Term
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Definition
| responsible for conscious or voluntary movement of skeletal muscles; located in the precentral gyrus of the frontal lobe |
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Term
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Definition
| considered the most superior portion of the brain stem; includes the thalamus, hypothalamus and epithalamus |
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Term
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Definition
| structures include midbrain, the pons and the medulla oblongata |
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Term
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Definition
| elaborate type of rough endoplasmic reticulum involved in metabolic activities of cell; found in neuron cell body |
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Term
| Medulla Oblongata (Medulla) |
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Definition
| connects the spinal cord and the pons and is anterior to the cerebellum; contains center for regulating activities such as heartbeat and reflex centers for vomiting, coughing, etc. |
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Term
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Definition
| a bridge connecting the cerebellum with the rest of the CNS; also serves as a regulatory center for breathing and reflex centers for movement in response to visual and auditory stimuli |
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Term
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Definition
| surrounds the cerebral aqueduct and acts as a relay station between cerebrum & spinal cord or cerebellum and a reflex center for visual, auditory & tactile stimuli |
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Term
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Definition
| front portion of the brain; responsible for consciousness; divided into 2 hemispheres each of which contains a lateral ventricle |
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Term
| 4 Lobes of Cerebral Hemispheres |
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Definition
| frontal, parietal, temporal & occipital |
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Term
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Definition
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Term
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Definition
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Term
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Definition
| major commissure connecting the 2 hemispheres at its base |
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Term
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Definition
lies at the back of the brain below the cerebrum; consists of 2 hemispheres joined by a worm like vermis; gray matter on outside; white matter on inside; controls & coordinates much of our movement without conscious thought, "automatic pilot"
fibers converge on this from the equilibrium apparatus of the inner ear, visual pathways, proprioceptors of tendons and skeletal muscles; remains constantly aware of the position & state of tension of various body parts |
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Term
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Definition
| fiber tracts found in the cerebral hemisphere white matter connecting 2 portions of the same hemisphere. |
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Term
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Definition
| fiber tracts found in the cerebral hemisphere white matter running between the cerebral cortex and the lower brain or spinal cord |
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Term
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Definition
| fiber tracts found in the cerebral hemisphere white matter running from one hemisphere to another |
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Term
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Definition
| bandlike fiber tract concerned with olfaction as well as limbic system functions; located between the lateral verntricles & the cerebral peduncles/corpora quadrigemina |
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Term
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Definition
| separates the lateral ventricles of the cerebral hemispheres |
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Term
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Definition
| important group of nuclei buried deep within the white matter of cerebral hemispheres, flanking the lateral and third ventricles; part of the extrapyronridal system & involved in regulating voluntary motor activities; include the caudate nucleus & lentiform nucleus, which is composed of the putamen & globus pallidus nuclei and the corona radiata |
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Term
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Definition
| part of the basal ganglia; a spray of projection fibers coursing down from the precentral (motor) gyrus, combining with sensory fibers traveling to the sensory cortex to form a broad band of fibrous material called the internal capsule |
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Term
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Definition
| broad band of fibrous material; combination of corona radiata and sensory fibers traveling to the sensory cortex |
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Term
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Definition
| "striped body"; caudate nucleus & putamen portion of the lentiform nucleus |
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Term
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Definition
| consists of 2 large lobes of gray matter; major integrating and relay station for sensory impulses passing upward to the cortical sensory areas for localization and interpretation |
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Term
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Definition
| makes up the floor and inferolateral walls of the 3rd ventricle; important autonomic center involved in regulation of body temp, water balance, fat & carbohydrate metabolism, as well as many other activities and drives (sex, hunger, thirst). |
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Term
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Definition
| relay stations for olfaction |
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Term
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Definition
| forms the roof of the 3rd ventricle; important structures include the pineal body and the choroid plexus |
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Term
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Definition
| treelike branching of the cerebellar white matter |
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Term
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Definition
| Motor response to a stimulus which is mediated over a neural pathway called a reflex arc. |
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Term
| 5 Essential Components of a Reflex Arc |
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Definition
| receptor, sensory neuron, integration center, motor neuron, effector |
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Term
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Definition
| abdominal, Achilles, corneal, crossed-extensor, gag, patellar, plantar |
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Term
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Definition
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Term
| Superficial Cord Reflexes |
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Definition
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Term
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Definition
| ciliospinal & pupillary light |
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Term
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Definition
| Patellar, crossed-extensor & Achilles |
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Term
| Somatic reflexes in which the higher brain centers participate |
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Definition
| abdominal, plantar, corneal & gag |
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