Term
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Definition
glial cells
- provide structural and functional support and protection to neurons
- outnumber neurons 10:1 but not directly involved in transmission of info or impulses through the nervous system
- rather they are important parts of the infrastructure necessary for the neurons to do their job |
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Term
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Definition
- basic, functional units of the nervous system
- the smallest pieces of the system that show basic nervous system functions, such as responding to stimuli and conducting impulses from one part of the cell to another
- high maint
- high requirement for o2, can’t live w/o for long
- that’s why CPR must be started w/in a few min of cardiac arrest – heart may start beating again after that but could be brain damage if neurons w/o O2 for long
- shortly after animal born, its neurons lose their ability to repro but they can regen cell processes if the vcell body remains intact
- this lack of repro ability is why serious nervous system, such as strokes and spinal cord damage, are often so debilitating and have such long-term effects |
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Term
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Definition
- central cell body (soma or perikaryon)
- cell processes
dendrites – receive stimuli
axons – conducts nerve impulses away |
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Term
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Definition
- receive stimuli from other neurons and conduct the stimuli to the cell body
- may serve as sensory receptors for heat, cold, touch, pressure, stretch, or other physical changes from inside or outside the body
- short, numerous and multibranched |
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Term
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Definition
- conduct nerve impulse away from cell toward another neuron or an effector cell
- single, long process; may be covered with myelin
- white matter; tissue containing myelinated axons
- myelinated axons conduct impulses faster than unmyelinated one
- myelin sheath; cell memb of glial cells tightly wrapped around the axon
oligodendrocytes in the brain and spinal cord
schwann cells in the nerves outside the brain and spinal cord
- mult Schwann cells or oligodendrocytes cover the entire length of the axon
- nodes of Ranvier; gaps between adjacent glial cells |
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Term
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Definition
- specialized molecule that helps maintain cell resting state
- Pumps (Na+) from inside of neuron to the outside
- pump (K+) from outside of neuron to inside |
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Term
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Definition
- neuron receives external stimuli
- sodium channel opens on neuron cell membrane
- sodium ions flow into cell by passive diffusion
- Action potential
during depolarization, inside of the neuron goes from a negatively charged resting membrane potential to a net positive charge due to inflow of sodium ions
creates large change in electrical charge from negative to positive |
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Term
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Definition
- sodium channels close
- K+ channels
- K+ diffuses out of cell
- resting state restored |
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Term
| Central Nervous System (CNS) |
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Definition
- brain and spinal cord
- one of two main divisions of the nervous system |
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Term
| Peripheral Nervous System (PNS) |
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Definition
- cordlike nerves that link the CNS with the rest of body
- extends 0utward from the central axis toward the periphery of the body
- cranial nerves originate directly from the brain
- spinal nerves emerge from the spinal cord |
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Definition
- conduct nerve impulses toward the CNS
- also called sensory nerves – conduct sensations from sensory receptors in the skin and other locations in the body to the CNS |
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Definition
- conduct nerve impulses away from the CNS
- also called motor nerves – cause skeletal muscle contraction and movement |
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Definition
- controls and coordinates autonomic fxns
- ex: slowing of the HR in response to increased BP |
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Definition
| - actions under conscious or voluntary control |
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Term
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Definition
- stimulus must be sufficient to make the neuron respond and cause complete depolarization
- “all or nothing principle” – neuron depolarizes to its max strength or not at all
- conduction of the action potential – spreading wave of opening sodium channels in sufficient numbers to allow sodium influx and depolarization – wave of depolarization or nerve impulse |
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Term
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Definition
- time period during which a neuron is insensitive to add’l stimuli – cell is still in depol/early repol
- absolute refractory period – during sodium influx and early potassium outflow
- relative refractory period – during end of the repol period
may be poss to stim another depol if stim is very lg |
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Term
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Definition
| junction between two neurons or a neuron and a target cell |
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Definition
| gap between adjacent neurons |
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Definition
| neuron bringing the depolarization wave to the synapse (releases neurotransmitter) |
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Term
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Definition
| contains receptors for the neurotransmitter |
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Definition
- rapid means of conducting an action potential
- depol in myelinated axons can only take place at the nodes of Ranvier |
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Term
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Definition
branched structure on presynaptic neuron
terminal bouton – slightly enlarged bulb on each end of telodendron (synaptic end bulb, synaptic knob)
vesicles in the knob contain the neurotransmitter |
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Term
| Process of synaptic transmission |
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Definition
- when depolarization wave reaches synaptic knob, vesicles fuse with the knob’s cellular membrane and dump neurotransmitter into the synaptic cleft
- neurotransmitters diffuse across the synaptic cleft towards the postsynaptic membrane
- receptors on the postsynaptic membrane bind the neurotransmitter |
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Term
| Types of neurotransmitters |
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Definition
- excitatory neurotransmitters
usually cause an influx of sodium so that the postsynaptic membrane moves toward threshold
- inhibitory neurotransmitters
move the charge w/in the postsynaptic cell farther away from threshold
- Acetylcholine
can be either excitatory or inhibitory depending on its location in the body
- Catecholamines
norepinephrine and epinephrine – assoc w/ “fight or flight” rxns of the sympathetic nervous system
Dopamine – involved w/ autonomic fxns and muscle control
- Gamma-aminobutyric acid (GABA) and glycine-inhibitory |
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Term
| - excitatory neurotransmitters |
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Definition
| usually cause an influx of sodium so that the postsynaptic membrane moves toward threshold |
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Term
| - inhibitory neurotransmitters |
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Definition
| move the charge w/in the postsynaptic cell farther away from threshold |
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Term
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Definition
| can be either excitatory or inhibitory depending on its location in the body |
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Term
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Definition
norepinephrine and epinephrine – assoc w/ “fight or flight” rxns of the sympathetic nervous system
Dopamine – involved w/ autonomic fxns and muscle control |
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Term
| - Gamma-aminobutyric acid (GABA) and glycine-inhibitory |
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Definition
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Term
| Recycling the Neurotransmitter |
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Definition
- Acetylcholinesterase – found on postsynaptic membrane, breaks down acetylcholine
- Monoamine oxidase (MAO) – breaks down norepinephrine
- Catechol-O-methyl transferase (COMT) – breaks down norepinephrine that is not reabsorbed |
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Term
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Definition
| found on postsynaptic membrane, breaks down acetylcholine |
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Term
| - Monoamine oxidase (MAO) |
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Definition
| breaks down norepinephrine |
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Term
| - Catechol-O-methyl transferase (COMT) |
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Definition
| breaks down norepinephrine that is not reabsorbed |
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Term
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Definition
Brain
- cerebrum
- cerebellum
- diencephalon
- brain stem
Spinal Cord |
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Term
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Definition
- gray matter – cerebral cortex; outer layer of brain, made up of neuron cell bodies
- white matter – myelinated axons in the CNS fibers beneath the cortex and corpus callosum (fibers that connect the two halves of the cerebral cortex
- area of the brain responsible for higher-order behaviors (learning, intelligence, awareness, etc)
- receives and interprets sensory info
- initiates conscious (voluntary) nerve impulses to skeletal muscle
- integrates neuron activity that is normally assoc w/ communication, expression of emotional responses, learning, memory and recall, and other behaviors assoc w/ conscious activity
- gyri (gyrus) – folds in cerebral hemispheres
- fissures – deep grooves separating the gyri
- sulci (sulcus) – shallow grooves separating the gyri – divides the cerebral hemispheres into lobes
- longitudinal fissue – prominent groove that divides the cerebrum into R and L cerebral hemispheres |
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Term
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Definition
| outer layer of brain, gray matter, made up of neuron cell bodies |
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Definition
| fibers that connect the two halves of the cerebral cortex, myelinated axons in the CNS, white matter |
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Term
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Definition
| (gyrus) – folds in cerebral hemispheres |
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Term
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Definition
| (sulcus) – shallow grooves separating the gyri – divides the cerebral hemispheres into lobes |
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Term
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Definition
| prominent groove that divides the cerebrum into R and L cerebral hemispheres |
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Term
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Definition
- each hemisphere divided by sulci into lobes
- different lobes specialize in certain fxns |
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Term
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Definition
- located just caudal to the cerebrum
- area of the brain resp for coordinated movement, balance, posture, and complex reflexes |
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Term
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Definition
- passageway between brain stem and cerebrum
- structures assoc w/ diencephalon:
- thalamus – acts as a relay station for regulating sensory impulses to the cerebrum
- hypothalamus – interface between the nervous system and the endocrine system
- pituitary – endocrine “master gland” that regulates hormone production and release throughout body |
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Term
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Definition
| in diencephalon - acts as a relay station for regulating sensory impulses to the cerebrum |
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Term
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Definition
| in diencephalon - interface between the nervous system and the endocrine system |
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Term
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Definition
| in diencephalon - endocrine “master gland” that regulates hormone production and release throughout body |
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Term
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Definition
- connection between the rest of the brain and the spinal cord
- composed of the medulla oblongata, the pons and the midbrain
- resp for basic support fxns of the body
- damage to brain stem can result in resp failure or CV collapse
- many of the cranial nerves originate from the area of brain |
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Term
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Definition
| – the part of the brain stem just above (cranial to) the spinal cord |
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Term
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Definition
| a part of the brain stem located just rostral to the medulla oblongata |
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Term
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Definition
| mesencephalon, part of the brain stem |
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Term
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Definition
- connective tissue layers that surround brain and spinal cord
- contain blood vessels, fluid, and fat
supply nutrients and oxygen to the superficial tissues of brain and spinal cord
provide some cushioning and distribution of nutrients for the CNS
- 3 layers
dura mater – tough, fibrous
arachnoid – delicate, spiderweb-like
pia mater – very thin, lies directly on surface of brain and spinal cord |
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Term
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Definition
| – the outermost layer of the meninges that covers the brain and spinal cord, toughest of the meninges |
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Term
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Definition
| innermost layer of meninges, very thin, lies directly on surface of brain and spinal cord |
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Term
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Definition
| the delicate, weblike layer of the meninges between the dura mater and the pia mater |
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Term
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Definition
| cell membrane of glial cells (eg oligodendrocytes, Schwann cells) wrapped around an axon; increases speed of impulse conduction along the axon |
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Term
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Definition
| glial cells in the brain and spinal cord whose cellular membrane forms the myelin sheath for axons in the CNS |
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Term
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Definition
| glial cells assoc with the peripheral nerves whose cellular membrane forms the myelin sheath for axons in the PNS |
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Term
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Definition
| unmyelinated areas of the axon between two adjacent Schwann cells that are involved in rapid conduction of nerve impulses along the axon |
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Term
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Definition
| CSF – fluid that bathes and protects the brain and spinal cord from the hard inner surface of the skull and spinal vertebrae |
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Term
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Definition
| the functional barrier between the capillaries in the brain and the nervous tissue; anatomically composed of capillary walls w/o the openings found in other capillaries and glial cells |
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Term
| Mnemonics for 12 cranial nerves |
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Definition
On old Olympus’ towering top, a fine, vocal German viewed some hops
(Olfactory – Hypoglossal)
Six sailors made merry, but my brother said :Bad business, my man.”
(Sensory – Motor) |
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Term
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Definition
| cluster of neuron cell bodies outside of the CNS |
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Term
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Definition
| a reflex resulting in the stimulation or inhibition of skeletal muscle contraction |
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Term
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Definition
| a reflex that results in inhibition or stimulation of smooth or cardiac muscle or endocrine gland fxn; mechanisms of homeostasis are autonomic reflexes |
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Term
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Definition
reflex arc in which painful stimulus on skin causes contraction of the affected limb, also called the flexor reflex
- Although the reflex arc may involve several interneurons, several motor neurons and several diff segments of the spinal cord, the reflex occurs w/o the brain being aware of the incident (the limb is withdrawn from the painful stimulus before the brain becomes consciously aware of the painful stimulus |
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Term
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Definition
| reflex initiated by a stimulation of a limb that results in extension of the limb on the other side of the body |
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Definition
| reflex response that is more pronounced than normal |
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Definition
| – reflex response is less than normal |
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Definition
– reflex initiated by stretch receptors w/in a muscle that results in contraction of the muscle to compensate for the stretching
– simple, monosynaptic or two-neuron reflex arc because it involves only a sensory neuron and a motor neuron (w/ only one synapse between them) w/o any interneurons
– the sensory receptor in a stretch reflex arc is a specialized structure w/in the muscle called a muscle spindle
– if a muscle is stretched, the muscle spindle also stretches and sends impulses via the somatic sensory neuron to the spinal cord
– at the spinal cord, the sensory neuron synapses w/ the motor neuron that innervates the same muscle
– stimulation of the motor neuron causes that muscle to contract in response to stretching of the muscle
– in this way, the body can maintain the tension or tone of a muscle to meet an increased force applied to stretch the muscle, or it can prevent an overstretching of the muscle caused by contraction of opposing muscles |
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Term
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Definition
- Reflex closure of the eyelids when the medial canthus of the eyelids is touched
- Used in anes monitoring to assess the anes depth |
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Term
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Definition
| - PLR – reflex in which light is shown in one eye and the pupil constricts in both eyes |
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