Term
| The nervous system acts along with endocrine system to maintain |
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Definition
|
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Term
The nervous system allows a
while the endocrine system acts |
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Definition
| Quick, slowly and last longer |
|
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Term
| consists of the brain and spinal cord which lie in the midline of the body |
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Definition
|
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Term
| includes all of the cranial and spinal nerves and is found in peripheral body regions. The two systems are connected and work together. |
|
Definition
| peripheral nervous system |
|
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Term
| Why is the nervous system able to serve as a control and communications network |
|
Definition
| Because two properties of protoplasm called signaling properties are highly developed |
|
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Term
| Refers to the capacity of nerve tissue to react to various chemical stimuli |
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Definition
|
|
Term
| Refers to the ability of nervous tissue to transmit stimuli from one place to another. |
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Definition
|
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Term
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Definition
| conveys information to the central nervous system from receptors. |
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Term
| which carry impulses from the skin, skeletal muscles and joints |
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Definition
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Term
| carry impulses form the viscera ( internal organs). |
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Definition
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Term
| - Receptors in the skin and organs respond to external stimuli by generating nerve impulses. |
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Definition
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Term
| 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 |
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Definition
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Term
| 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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Definition
|
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Term
| 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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Definition
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Term
| (also called the voluntary nervous system) which carries impulses to skeletal muscles |
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Definition
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Term
| whose motor fibers regulate the activity of smooth muscles, cardiac muscles and glands involuntary |
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Definition
|
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Term
| The autonomic nervous system has two subdivisions: |
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Definition
| sympathetic and paraympathetic |
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Term
| which activates the body to cope with stressors |
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Definition
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Term
| which oversees digestion, elimination and glandular function |
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Definition
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Term
| brain and sinal cord, integrative a control centers |
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Definition
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Term
| crainil nerves and spinal nerves, communication lies between the cns and the res of the body |
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Definition
| pERIPHERAL NERVOUS SYSTEM PNS |
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Term
| Somatic nd visceral snsory nere fibers conducts impuses from reeptors to theCNS |
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Definition
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Term
| motor nerve fibes conducts impulses from the cns to ffectors mscles and glands |
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Definition
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Term
| somatic motor voluntary,conducts implses from the CNS to sketal muscles |
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Definition
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Term
| visceral motor invountary conducts impules from the cns to cadiac smoothmuscles and glands |
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Definition
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Term
| conserves energy prmotes house keeping funtions duringrest |
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Definition
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Term
| obilizesbody during activity |
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Definition
|
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Term
| these ells conduct nerve impluses |
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Definition
|
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Term
| These cells support, defend and nourish neurons. |
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Definition
|
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Term
twine around neurons to form a supporting network in the brain and spinal cord. These cells synthesize neurotransmitters and have vascular feet which attach neurons to blood vessels allowing transport between the two.
cns |
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Definition
|
|
Term
| These cells help to hold nerve fibers together and produce the myelin sheath in the CNS |
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Definition
|
|
Term
| These phagocytic cells engulf microbes and debris in injured areas. |
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Definition
|
|
Term
| These cells line cavities of the brain and spinal cord and aid in production and circulation of the cerebrospinal fluid (CSF). The CSF cushions the brain and spinal cord and cilia beat to aid in its circulation. |
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Definition
|
|
Term
| These cells control the chemical environment around neurons PNS |
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Definition
|
|
Term
| These cells form the myelin sheath in the peripheral nervous system and are phagocytic. They remove cell debris and are essential to peripheral nerve regeneration. |
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Definition
|
|
Term
| Receive information from other neurons and typically conduct impulses toward the cell body. |
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Definition
|
|
Term
| Normally conducts impulses away from the cell body. ====may branch forming axon collaterals and form synaptic knobs at their ends. |
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Definition
|
|
Term
| Receives contains the nucleus and typical cytoplasmic organelles |
|
Definition
|
|
Term
| Normally information is received through dendrites and transmitted out via axons. This phenomenon is referred to as |
|
Definition
|
|
Term
| Nerve fibers may be myelinated or nonmyelinated |
|
Definition
| Myelinated fibers are covered with a fatty myelinated sheath and nonmyelinated fibers are not covered |
|
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Term
| Myelinated fibers we said are covered by myelin sheath. This myelin sheath is produced |
|
Definition
| by Schwann cells in PNS and by oligodendrocytes in the CNS. |
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Term
| wraps around nerve fiber in “jelly roll” fashion |
|
Definition
|
|
Term
| contains nucleus and most of cytoplasm of the Schwann cell. |
|
Definition
|
|
Term
| Gaps in myelin sheath are called |
|
Definition
|
|
Term
| These gaps allow impulses to jump from node to node. |
|
Definition
| In the PNS Nodes of Ranvier are formed by gaps between Schwann cells |
|
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Term
| Impulse Conduction faster or slower in myelinated fibers than nonmyelinated fibers. |
|
Definition
|
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Term
| Neurons Classified in Two Ways |
|
Definition
1. Function or the direction in which the nerve impulse travels.
2. Structure (number of processes) |
|
|
Term
| These cells transmit impulses away from the brain or spinal cord toward a muscle or gland. The cell bodies are located in the CNS. |
|
Definition
|
|
Term
| These cells carry impulses toward the spinal cord and brain. Their cell bodies are found in ganglia outside the CNS |
|
Definition
|
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Term
| These cells conduct impulses from sensory to motor neurons. |
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Definition
|
|
Term
| These neurons have one axon and several dendrites. this is the most common type in humans and the major type in the CNS. |
|
Definition
|
|
Term
| Bipolar neurons have one axon and one dendrite and are located in the retina, the inner ear and the olfactory mucosa. |
|
Definition
|
|
Term
| 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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Definition
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Term
| controls movement and balance. Outer cortex of gray matter contains purkinje cell layer between molecular and granular layers. |
|
Definition
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|
Term
| Section of cerebral cortex showing pyramidal cells |
|
Definition
|
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Term
| is measured as the potential difference between two charges. the greater the charge difference the higher the |
|
Definition
|
|
Term
| Flow of electrical charge from one point to another |
|
Definition
|
|
Term
| This is what we use for work such as turning on a light. The amount of charge moving between 2 points is dependent upon voltage and resistance. this relationship is expressed as |
|
Definition
|
|
Term
States that current (I) is directly proportional to voltage and inversely proportional to resistance which is basically provided by anything that stops charge flow such as insulation:
I = V
R |
|
Definition
|
|
Term
| A slight charge difference exists between the inside and outside of the membrane. There is a potential difference on either side of membranes when: |
|
Definition
| The number of ions is different across the membrane (2) The membrane provides a resistance to ion flow |
|
|
Term
| we see that voltage and resistance to current flow are provided |
|
Definition
|
|
Term
Proteins serve a membrane ion channels.
Ion channels – Two Types |
|
Definition
Passive or leakage channels are always open
2. Active or gated have protein molecules which change shape |
|
|
Term
| Open when a neurotransmitter binds |
|
Definition
|
|
Term
| Open when there is a change in voltage. |
|
Definition
|
|
Term
| The channel remains closed when a neurotransmitter is not bound to the extracellular receptor. Therefore Na+ cannot enter the cell and K+ cannot exit the cell. The channel |
|
Definition
|
|
Term
| when a neurotransmitter is attached to the receptor. Na+ enters the cell and K+ |
|
Definition
|
|
Term
The channel is closed when the intracellular environment is negative. Therefore,
Na+ cannot enter the cell. The channel is open
when the intracellular environment is positive
Therefore, Na+ can enter the cell. |
|
Definition
|
|
Term
| When gated channels are open |
|
Definition
Ions move across the membrane along their electrochemical gradients.
An electrical current is created and voltage changes across the membrane |
|
|
Term
| Ions move along chemical gradients from high to low concentration |
|
Definition
|
|
Term
| Ions also move toward areas of opposite charge in an electrical gradient. Therefore have |
|
Definition
|
|
Term
| When a neuron is at rest, the inside of membrane is negatively charged in comparison with outside. This charge difference is referred to as the |
|
Definition
| resting membrane potential. |
|
|
Term
| We have an unequal charge distribution across the membrane with a slight negative charge inside. Therefore, sodium ions are strongly attracted inside. All of this is stabilized by the sodium potassium pump |
|
Definition
| which removes three sodium ions from a cell and carries 2 potassium back in. This process uses ATP |
|
|
Term
The charge difference across a membrane at rest is referred to
as the resting membrane potential. |
|
Definition
This is difference of -70mV
is maintained by diffusion through passive leakage channels
and the sodium potassium pump. |
|
|
Term
| Resting Membrane Potential Differences in ionic makeup |
|
Definition
ICF has lower concentration of Na+ and Cl– than ECF
ICF has higher concentration of K+ and negatively charged proteins (A–) than ECF |
|
|
Term
| Differential permeability of membrane |
|
Definition
Impermeable to A–
Slightly permeable to Na+ (through leakage channels)
75 times more permeable to K+ (more leakage channels)
Freely permeable to Cl– |
|
|
Term
| Negative interior of the cell is due to much greater diffusion of |
|
Definition
| K+ out of the cell than Na+ diffusion into the cell |
|
|
Term
| Changes in membrane potential serve as signals to integrate, send, and receive information. These changes are due to |
|
Definition
(1) changes in membrane permeability to ions
(2) alterations of ion concentrations across the membrane. |
|
|
Term
| the inside of the membrane becomes less negative |
|
Definition
|
|
Term
| the membrane returns to its resting membrane potential |
|
Definition
|
|
Term
| the inside of the membrane becomes more negative than the resting potential |
|
Definition
|
|
Term
| The membrane potential moves toward 0 mV, the inside becoming less negative (more positive). Depolarization results in a reduction in membrane potential and increases probability of producing nerve impulse. |
|
Definition
|
|
Term
membrane potential becomes more
negative decreasing the probability of a nerve impulse |
|
Definition
|
|
Term
|
Definition
Graded potentials
2. Action potentials |
|
|
Term
| potentials are 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 the stimulus. If they are sufficiently strong, |
|
Definition
| graded potentials can initiate action potentials. |
|
|
Term
| are only generated by muscle cells (muscle action potentials) and neurons (nerve impulses). Neuronal action potentials are the principal means of neural communication. |
|
Definition
|
|
Term
| is a large, but brief, self-propagating wave of depolarization which neither decreases nor increase in strength over distance. It is an “All or Nothing” phenomenon. The action potential has several distinct phases; depolarization, repolarization and hyperpolarization. When not generating an action potential, the axonal membrane is in a resting state. |
|
Definition
|
|
Term
| all gated na and k channels closed na activation gates closed inactivation gates open |
|
Definition
|
|
Term
| na chnnels open rapidly kchannelsopen slowly |
|
Definition
|
|
Term
| na channels close rapidly and k channels remain open |
|
Definition
|
|
Term
| na activaton gates closedinactivation gats open k chanels slowly closing |
|
Definition
|
|
Term
| The large influx of Na + ions, occurring when the voltage-gated Na + channels rapidly open, creates a current, the Na + current, which depolarizes the adjacent membrane of the axon. As this depolarization reaches the threshold of the adjacent, voltage-gated channels (-55 to -50 mv), that adjacent section of axon membrane enters phase 2, the depolarization phase, of the action potential. This process repeats itself to the end of the axon, producing a self-propagating wave of depolarization. Although the Na + currents are generated in both directions, the action potential moves in only one direction because those voltage-gated Na + channels previously stimulated are in a refractory period, a brief period during which they can not be stimulated |
|
Definition
| Action Potential Propagation: Mechanism |
|
|
Term
| Larger diameter fibers have less resistance to local current flow and have faster impulse conduction. |
|
Definition
|
|
Term
| Continuous conduction in unmyelinated axons is slower than saltatory conduction in myelinated axons |
|
Definition
|
|
Term
| takes place in unmyelinated fibers. The wave of depolarization travels down the length of the axon. |
|
Definition
|
|
Term
| takes place in myelinated fibers where the impulse jumps from Node of Ranvier to Node of Ranvier. This conducts the impulse more rapidly |
|
Definition
|
|
Term
| Large diameter, myelinated somatic sensory and motor fibers |
|
Definition
|
|
Term
| Intermediate diameter, lightly myelinated ANS fibers |
|
Definition
|
|
Term
| Smallest diameter, unmyelinated ANS fibers |
|
Definition
|
|
Term
| are places where nerve impulses are transmitted from one neuron called a presynaptic neuron to another neuron called the postsynaptic neuron. There are two types of synapses |
|
Definition
|
|
Term
| allow ion flow directly from one neuron to another. |
|
Definition
|
|
Term
| are places where neurotransmitters are released and bound. |
|
Definition
|
|
Term
| have protein channels which connect the cytoplasm of adjacent neurons. This low resistance pathway allows ions to flow from one neuron to the next. Such cells are said to be electrically coupled. And allow rapid transmission and synchronization of interconnected cells . We see electrical synapses in electrically excitable tissues such as cardiac and smooth muscle. |
|
Definition
|
|
Term
| Structurally chemical synapses consist of a |
|
Definition
| synaptic knob, a synaptic cleft, and a postsynaptic membrane which will be the cell membrane of the dendrite or cell body |
|
|
Term
| is a space between the synaptic knob and the postsynaptic membrane. The postsynaptic membrane has receptors for neurotransmitters. |
|
Definition
|
|
Term
| is a tiny distention at the end of one of the fine filaments at the end of the presynaptic axon. It contains vesicles containing neurotransmitter molecules. |
|
Definition
|
|
Term
| Chemical Synapse: The actual information transfer take place in several steps |
|
Definition
A nerve impulse moving down the axon opens voltage gated calcium ion channels cause calcium ions to flow in.
The calcium ion increase causes synaptic vesicles to fuse with the axonal membrane releasing neurotransmitters into the synaptic cleft.
Neurotransmitters diffuse across the synaptic cleft and bind to receptors in the postsynaptic membrane.
4. This opens ion channels to open causes local changes in the membrane potential which can excite or inhibit the postsynaptic membrane. |
|
|
Term
| Reflex arcs (pathways) have five essential components: |
|
Definition
| receptor, sensory neuron, CNS integration center, motor neuron, and effector. |
|
|
Term
| In these circuits, a single incoming fiber stimulates neurons in parallel arrays leading to a single output. This circuit may be involved in complex mental activity such as solving math problems. |
|
Definition
| Parallel After Discharge Circuits |
|
|
Term
| the impulse is sent through the circuit over and over until one neuron fails. This type of circuit is involved in rhythmic activities such as breathing. |
|
Definition
| In reverberating or oscillating circuits |
|
|
Term
| Impulses from several incoming fibers converge on one neuron. This makes summation of information from different sources possible. For example: you might pick up a baby, smell a dirty diaper and see the baby smile and this would lead to an outpouring of love. |
|
Definition
|
|
Term
| an impulse leaving the pool may pass into several output fibers. This allows for amplification. For example: input from a single sensory receptor can be carried up the spinal cord and then to several different regions of the brain. You might walk into the house and smell chili (sensory input) you could feel hunger and know what supper is!! |
|
Definition
|
|
Term
| cns neurons are organizd into |
|
Definition
|
|
Term
| Some excite or inhibit and some do both. |
|
Definition
|
|
Term
Direct neurotransmitters bind to and open ion channels directly.
b. Indirect neurotransmitters act through second messengers. This will be discussed in later chapters. |
|
Definition
|
|
Term
| Some excite or inhibit and some do both. |
|
Definition
|
|
Term
| are lipid soluble and are synthesized on demand from membrane lipids. They bind with G protein–coupled receptors in the brain and are involved in learning and memory. |
|
Definition
|
|
Term
| may be involved in long term learning. |
|
Definition
|
|
Term
| may regulate cyclic GMP in the brain. |
|
Definition
|
|
Term
| adenosine triphosphate (ATP) produce a quick excitation when they bind to the appropriate receptors. Adenosine is a strong inhibitor in the brain. |
|
Definition
|
|
Term
|
Definition
Substance P mediates pain signals
Enkephalins and endorphins bind to pain receptors in brain and reduce our perception of pain |
|
|
Term
| These chemicals are widespread in the brain and help to regulate emotional behavior and the biological clock. Norepinephrine may be found in the autonomic system. These are often called “feeling good” neurotransmitters. If epinephrine levels are low, we may feel depressed. If imbalances occur can cause mental illness such as schizophrenia. |
|
Definition
|
|
Term
|
Definition
| catecholamines: dopamine, norepinephrine, epinephrine and the indolamines: serotonin and histamine. These are broadly distributed in the brain and play roles in emotional behaviors and the biological clock |
|
|
Term
| gamma aminobutyric acid leads to inhibition in CNS by hyperpolarizing the postsynaptic membrane. Glycine, glutamate, and asparate may also be implicated. |
|
Definition
|
|
Term
| is the neurotransmitter found in skeletal muscle. It Increases permeability of postsynaptic membrane to Na+ and K+ by opening receptors. The inward movement of sodium depolarizes the membrane and a nerve impulse is generated. If allowed to continue, the nerve impulse would proceed indefinitely. This is prevented by release of the enzyme acetylcholinesterase which breaks down acetylcholine in 1/500 second. This permits the membrane to repolarize almost immediately so that another impulse may be generated. |
|
Definition
|
|
Term
| In order to be a neurotransmitter, a chemical must meet certain requirements. It must: |
|
Definition
Be present in presynaptic terminals
Produce ion fluxes
Be removed naturally from synaptic junction by either enzymatic inactivation or reuptake |
|
|
Term
| Neurotransmitters are chemicals released from presynaptic neurons which interact with receptors on postsynaptic membranes. They regulate many body activities such as sleep, hunger, and emotions. Most neurons make two or more neurotransmitters, which are released at different stimulation frequencies. Fifty or more neurotransmitters have been identified. |
|
Definition
|
|
Term
| One or more presynaptic neurons transmit impulses in rapid-fire order |
|
Definition
|
|
Term
| Postsynaptic neuron is stimulated by a large number of terminals at the same time |
|
Definition
|
|
Term
single EPSP cannot induce an action potential
EPSPs can summate to reach threshold
IPSPs can also summate with EPSPs, canceling each other out |
|
Definition
|
|
Term
is a local
hyperpolarization of the
postsynaptic membrane
and drives the neuron
away from AP threshold.
Neurotransmitter binding
opens K+ or Cl– channels. |
|
Definition
|
|
Term
| potential decreases the probability that an impulse will occur by pushing the membrane potential further away from threshold. |
|
Definition
| An inhibitory postsynaptic potential |
|
|
Term
is a local
depolarization of the
postsynaptic membrane
that brings the neuron
closer to AP threshold.
Neurotransmitter binding
opens chemically gated
ion channels, allowing
the simultaneous pas-
sage of Na+ and K+. |
|
Definition
|
|
Term
increases the probability
that an impulse will occur. |
|
Definition
| An excitatory postsynaptic potential (EPSP) |
|
|
Term
| The effects of transmission across a synapse depends upon: |
|
Definition
The rate at which the neurotransmitter reaches the receptors on the postsynaptic membrane
The interaction of the neurotransmitter and the receptor.
This can cause excitatory or inhibitory postsynaptic potentials. |
|
|
Term
| is the largest ventricle. It extends into the cerebral hemispheres; occupies part of frontal, temporal and occipital lobes. For a stretch the two ventricles are only separated by a thin septum pellucidum. |
|
Definition
|
|
Term
| ventricle is located on midline of the brain and is connected with the lateral ventricles through the ventricular foramen. |
|
Definition
|
|
Term
| is located in the brain stem just in from of the cerebellum. It connects with the third ventricle by the cerebral aqueduct running lengthwise through the brain stem and connects with the central canal of the spinal cord inferiorly |
|
Definition
|
|
Term
| is the front portion of the brain and is responsible for consciousness. It is divided into two cerebral hemispheres each of which contains a lateral ventricle. The outer gray matter called the cerebral cortex is folded into sulci or grooves and gyri or folds |
|
Definition
|
|
Term
|
Definition
|
|
Term
| connects the two hemispheres at its base of the longitudinal fissure |
|
Definition
|
|
Term
is involved in motor function and thought.
separated from the parietal lobe by the central sulcus. The precentral gyrus is anterior to the central sulcus and the postcentral gyrus is behind it. |
|
Definition
|
|
Term
| is separated from the occipital lobe by the parietooccipital sulcus. This lobe is involved in speech and visual perception. |
|
Definition
|
|
Term
| Located at the back of the cerebrum, the is involved in visual perception. |
|
Definition
|
|
Term
| The lateral sulcus outlines the lobe. Deep in the lateral sulcus and forming part of its floor is the insula |
|
Definition
|
|
Term
| The brain stem contains the medulla oblongata, pons and midbrain. The medulla connects |
|
Definition
| the spinal cord and the pons and is anterior to the cerebellum. It contains center for regulating activities such as heartbeat and reflex centers for vomiting, coughing, etc. |
|
|
Term
| is a bridge connecting the cerebellum with the rest of the CNS. It also serves as a regulatory center for breathing and reflex centers for movement in response to visual and auditory stimuli |
|
Definition
|
|
Term
| surrounds the cerebral aqueduct and acts as a relay station between cerebrum and spinal cord or cerebellum and a reflex center for visual, auditory and tactile stimuli. |
|
Definition
|
|
Term
| controls many motor activities and higher mental functions such as intelligence and reasoning. |
|
Definition
| A number of areas of the cerebral cortex have been linked to function. the are called Broadmann Areas. |
|
|
Term
| Conscious behavior involves the entire cortex. |
|
Definition
The three types of functional areas are:
Motor areas control voluntary movement.
Sensory areas allow conscious awareness of sensation.
Association areas integrate diverse information. |
|
|
Term
| Pyramidal cells in this area allow conscious control of skeletal muscles |
|
Definition
| Primary Somatic Motor Cortex |
|
|
Term
| This area controls learned motor skills of a patterned nature such as playing the piano and serves as a memory bank for skilled motor activities. |
|
Definition
|
|
Term
| Broca’s area is a motor speech area. it is found only in one hemisphere (usually the left) and controls motor activities involved in speech |
|
Definition
|
|
Term
| the frontal eye field controls voluntary eye movements. |
|
Definition
|
|
Term
| This area receives impulses from the sensory receptors in the skin, and from proprioreceptors allowing one to identify the area stimulated. |
|
Definition
| Primary Somatosensory Cortex |
|
|
Term
| are located in the parietal, temporal and occipital lobes. |
|
Definition
|
|
Term
| area integrates and analyzes somatic sensory inputs such as temperature, touch and pressure and pain. The primary sensory cortex would tell you that you are holding something. The somatosensory association area would tell you what you are holding |
|
Definition
| The Somatosensory association |
|
|
Term
| receive information from the retina and interpret this information in terms of past experiences. a lesion in this area could result in dyslexia or word blindness |
|
Definition
| the visual cortx and the visual association |
|
|
Term
| Receives information from hearing receptors in the cochlea and its association area interprets the sound. |
|
Definition
|
|
Term
Olfactory is involved in odor perception.
5. Gustatory is involved in perception of taste.
6. Wernickes Area is involved in understanding of written and spoken language. |
|
Definition
|
|
