Wk 4 Vocab Flashcards
Acetylcholine
A neurotransmitter associated with somatic nerves
and with parasympathetic nervous system effects even though
it is used in the preganglionic neuron in both the sympathetic
and parasympathetic nervous systems; has a stimulatory effect
on the gastrointestinal tract, it increases secretions and muscle
contractions in the esophagus, stomach, ruminant forestomachs, intestine, and colon.
Acetylcholinesterase
The enzyme that breaks down acetylcholine.
Adrenergic neuron
Neurons that secrete catecholamines (e.g.,
norepinephrine) as their neurotransmitter.
Afferent nerve
Nerve that carries impulses toward the central
nervous system.
Anesthesia
insensitivity to pain, especially as artificially induced by the administration of gases or the injection of drugs before surgical operations.
Complete loss of sensation.
Arachnoid
a fine, delicate membrane, the middle one of the three membranes or meninges that surround the brain and spinal cord, situated between the dura mater and the pia mater.
The delicate, weblike layer of the meninges between the dura mater and the pia mater.
Autonomic nervous system
The part of the nervous system that
controls smooth muscle, cardiac muscle, and endocrine glands
automatically without conscious control; has motor and sensory
branches.
Autonomic reflex
unconscious motor reflexes relayed from the organs and glands to the CNS through visceral afferent signaling.
Axon
Extension of the neuron that conducts the nerve impulse away from the cell body to the terminal bouton (synaptic bulb) at the end of the neuron
Blood-brain barrier
A network of blood vessels and tissue that is made up of closely spaced cells and helps keep harmful substances from reaching the brain.
Brainstem
The connection between the rest of the brain and the
spinal cord, composed of the medulla oblongata, the pons, and
the midbrain; heavily involved in autonomic control functions
related to the heart, respiration, blood vessel diameter, swallowing, and vomiting.
Catecholamine
The group of neurotransmitters that includes
norepinephrine, epinephrine, dopamine, and others with
similar chemical properties.
Central nervous
system
(CNS) is made up of the brain and spinal cord. It is one of 2 parts of the nervous system.
Cerebellum
Second largest component of the brain; allows the
body to have coordinated movement, balance, posture, and
complex reflexes
Cerebral cortex
the outer layer that lies on top of your cerebrum. The largest area of the brain. Your cerebrum divides your brain into two halves called hemispheres
Gray matter that makes up the outer layer of the
cerebrum.
Cerebrospinal fluid
(CSF) Fluid that bathes and protects the
brain and spinal cord from the hard inner surface of the skull and spinal vertebrae.
Cerebrum
That portion of the brain responsible for functions
most commonly associated with “higher-order” behaviors
(learning, intelligence, awareness); receives and interprets
sensory information, initiates conscious (voluntary) nerve
impulses to skeletal muscles, and integrates neuron activity
that is normally associated with communication, expression of
emotional responses, learning, memory and recall, and other
behaviors associated with conscious activity.
Cholinergic neuron
Neurons that secrete acetylcholine as their
neurotransmitter.
Cholinergic receptor
Receptors for acetylcholine; may be muscarinic or nicotinic receptors
Contralateral reflex
Reflexes that are initiated on one side of the
body and travel to the opposite side to produce their effect.
Cranial nerve
Set of 12 pairs of nerves originating directly from
the brain; may be sensory or motor or may contain both sensory
and motor nerves.
Crossed extensor
reflex
a reflex in which the contralateral limb compensates for loss of support when the ipsilateral limb withdraws from painful stimulus in a withdrawal reflex.
Dendrite
The receptive sites of the nerve cell; they extend from the cell body, giving the cell a starlike shape; they receive stimuli and convey them as nerve impulses to the cell body.
Depolarization
A reduction in the voltage across a neuron or
muscle cell membrane from its normal polarized state (resting
membrane potential). This results in an action potential (nerve
impulse) in the case of a neuron or the initiation of contraction
in the case of a muscle cell.
Diencephalon
Serves as a nervous system passageway between
the primitive brainstem and the cerebrum; three major structures of the diencephalon are the thalamus, the hypothalamus,
and the pituitary.
Dopamine
A catecholamine neurotransmitter
Dorsal horn
The area of the spinal cord’s gray matter “butterfly”
where the neurons that forward sensory (afferent) nerve impulses
to the brain or other parts of the spinal cord are located.
Dorsal nerve root
The branch off each side of the spinal cord
between each set of adjacent vertebrae that conducts sensory
impulses into the spinal cord from the periphery of the body
Dura mater
The thick outermost layer of the meninges that
covers the brain and spinal cord; it is considered to be the toughest of the meninges.
Effector cell
A cell such as a muscle or gland cell that carries out
some action when stimulated by a nerve impulse.
Efferent nerve
nerve that carries impulses away from the central
nervous system.
Endocrine system
The system of glands that controls and regulates body functions through the internal secretion of hormones.The hormones are released directly into the bloodstream,
which allows them to exert their actions on target cells throughout the body
Enzyme
A specialized globular protein that carries out and/or speeds up chemical reactions in the body by acting as a catalyst and lowering the temperature necessary for the reaction to take place. Specific enzymes are exclusive to specific reactions, and
although they may change the rate of reaction, they are never changed or used up themselves in the process.
Epinephrine
Commonly called adrenaline. A hormone secreted
by the medulla of the adrenal gland under stimulation by the
sympathetic portion of the autonomic nervous system. It produces part of the fight-or-flight response that results when an
animal feels threatened
Excitatory
neurotransmitter
Excitatory neurotransmitters “excite” the neuron and cause it to “fire off the message,” meaning, the message continues to be passed along to the next cell. Examples of excitatory neurotransmitters include glutamate, epinephrine and norepinephrine
Fenestration
Small openings or holes (literally, windows); in the
walls of the glomerular capillaries, fenestrations allow certain
molecules to leave that would normally be too large to escape.
Fissure
Deep grooves found in the cerebral cortex.
GABA
Gamma-aminobutyric acid; inhibitory neurotransmitter.
Gamma-aminobutyric
acid
the chief inhibitory neurotransmitter in the developmentally mature mammalian central nervous system. Its principal role is reducing neuronal excitability throughout the nervous system.
Ganglion
Cluster of neuron cell bodies outside
the CNS.
Glial cell
Cells in the nervous system that support and protect neurons.
Glycine
Inhibitory neurotransmitter
Gray matter
That part of the CNS made up of neuron cell bodies.
Gyrus
The folds that provide the wrinkled appearance of the surface of the cerebral hemispheres.
Hypermetria
A condition in which voluntary movements become
jerky and exaggerated.
Hyperreflexia
is overactive or overresponsive bodily reflexes. Examples of this include twitching and spastic tendencies,
Hyporeflexia
a symptom in which your skeletal muscles have a decreased or absent reflex response.
Inhibitory
neurotransmitter
block or prevent the chemical message from being passed along any farther. Gamma-aminobutyric acid (GABA), glycine and serotonin are examples of inhibitory neurotransmitters.
Interneuron
Typically a short neuron that connects two other
neurons; usually mentioned in the context of the reflex arc
Ipsilateral reflex
The reflex stimulus and response are on the
same side of the body
Longitudinal fissure
Prominent groove that divides the cerebrum
into right and left cerebral hemispheres.
Medulla oblongata
The part of the brainstem just above (cranial
to) the spinal cord
Meninges
Set of connective tissues that surround the brain and
spinal cord; the three layers of the meninges, from outside to
innermost layer, are the dura mater, the arachnoid, and the pia
mater.
Midbrain
The mesencephalon
Mixed nerve
A nerve made up of both sensory nerve fibers and
motor nerve fibers.
Motor nerve
Nerve that carries efferent impulses to muscles,
although motor function may be used to describe any nerve that
carries an efferent impulse, including those that supply endocrine glands and tissues that are not muscle.
Muscarinic receptor
A type of cholinergic receptor that binds
with acetylcholine.
Muscle spindle
A sensory organ located within muscle that
detects stretch of the muscle.
Myelin
Fatty substance that covers some axons. When fixed for
microscopic examination, it appears white, hence myelinated
neurons make up the “white matter” of the brain and spinal
cord.
Myelin sheath
Cell membrane of glial cells (e.g., oligodendrocytes, Schwann cells) wrapped around an axon; increases speed
of impulse conduction along the axon.
Nerve impulse
A wave of cell membrane depolarization that
travels from the point of stimulus down the length of a nerve
cell process.
Nerve
A bundle of myelinated nerve fibers in the peripheral
nervous system that conduct sensory and/or motor impulses
to and from the central nervous system and the periphery of
the body.
Nerve fiber
An axon
Neuroglia
Auxiliary cells in the nervous system that support and
protect the neurons. Examples include oligodendrocytes,
microglia, and astrocytes
Neuron
cells of the nervous system that are structurally composed of a cell body (perikaryon), dendrites, and an axon. They
not only initiate nerve impulses but also conduct them
Neurotransmitter
A chemical released by the presynaptic neuron
that diffuses across the synaptic cleft, binds with the receptor on
the postsynaptic membrane, and stimulates (excitatory neurotransmitter) or inhibits (inhibitory neurotransmitter) the
postsynaptic neuron. Neurotransmitters also stimulate effector
cells such as muscle or gland cells.
Nicotinic receptor
A type of cholinergic receptor that binds with
acetylcholine.
Node of Ranvier
The depolarization wave in the myelinated
axon skips from one node of Ranvier to the next, greatly
accelerating the rate at which the depolarization wave moves
from the neuron cell body to the other end of the axon
Norepinephrine
a neurotransmitter and a hormone. It plays an important role in your body’s “fight-or-flight” response.
Oligodendrocyte
Glial cells in the brain and spinal cord whose
cellular membrane forms the myelin sheath for axons in the
CNS.
Palpebral reflex
Reflex closure of the eyelids when the medial
canthus of the eyelids is touched; used in anesthesia monitoring
to assess depth of anesthesia.
Parasympathetic
nervous system
a network of nerves that relaxes your body after periods of stress or danger
Perikaryon
The cell body of the neuron; soma.
Peripheral nervous
system
The peripheral nervous system is divided into two main parts: Autonomic nervous system (ANS): Controls involuntary bodily functions and regulates glands. Somatic nervous system (SNS): Controls muscle movement and relays information from ears, eyes and skin to the central nervous system.
Pia mater
The innermost layer of the meninges.
Pons
A part of the brainstem located just rostral to the medulla
oblongata.
Postganglionic neuron
In reference to the autonomic nervous
system, it is the second of two neurons that typically make up
the nerves of the autonomic nervous system; so called because
this neuron originates from a ganglion and carries the impulse
from it to the target organ or tissue.
Postsynaptic neuron
The neuron that contains the receptors to
which a released neurotransmitter binds, causing depolarization
or inhibition of depolarization of the neuron.
Preganglionic neuron
In reference to the autonomic nervous
system, it is the first of two neurons that typically make up the
nerves of the autonomic nervous system; so called because the
first neuron is located “before” the ganglion.
Presynaptic neuron
The neuron that is stimulated by the depolarization wave to release a neurotransmitter into the synapse
Pupillary light reflex
(PLR) Reflex in which light is shone into
one eye, and the pupil constricts in both eyes.
Receptor
In the context of the nervous system, a specialized
protein to which neurotransmitters bind.
Reflex
A rapid, automatic response to a stimulus, intended to protect the body and maintain homeostasis.
Reflex arc
The reflex arc is composed of the sensory receptor,
sensory neuron, interneuron(s), motor neuron, and target tissue
or organ involved with a stimulus and reflex response.
Refractory period
The period in the depolarization–
repolarization cycle when the neuron cannot be stimulated to
depolarize (absolute refractory period) or can only be depolarized with a greater than normal stimulation (relative refractory
period)
Repolarization
The process following depolarization wherein
potassium ions diffuse rapidly out of the neuron.
Resting membrane
potential
has a voltage across its membrane called the resting membrane potential, or simply the resting potential. The resting potential is determined by concentration gradients of ions across the membrane and by membrane permeability to each type of ion.
Resting state
In reference to neurons, more sodium ions are outside
the cell membrane than inside, and more potassium ions are inside
the cell; it is the state of the neuron before stimulation
Saltatory conduction
The skipping of the depolarization wave
(action potential) in a myelinated axon from one node of
Ranvier to the next node of Ranvier; means “leaping”
conduction.
Schwann cell
Glial cells associated with peripheral nerves whose
cellular membrane forms the myelin sheath for axons in the PNS.
Sensory nerve
Nerves that carry afferent impulses from sensory
receptors toward the central nervous system
Sensory neuron
Neuron carrying impulses toward the CNS.
Sensory receptor
A modified nerve ending that converts
mechanical, thermal, chemical, or electromagnetic stimuli into
nerve impulses that travel to the CNS and are interpreted as the
appropriate sensation.
Sodium-potassium
pump
an enzyme found in the membrane of all animal cells. It performs several functions in cell physiology. The Na⁺/K⁺-ATPase enzyme is active. For every ATP molecule that the pump uses, three sodium ions are exported and two potassium ions are imported.
Soma
The cell body of a neuron; perikaryon.
Somatic nervous system
a subdivision of your peripheral nervous system that stretches throughout nearly every part of your body. The nerves in this system deliver information from your senses to your brain. They also carry commands from your brain to your muscles so you can move around.
Somatic reflex
A reflex resulting in the stimulation or inhibition
of skeletal muscle contraction
Spinal nerve
Nerves of the peripheral nervous system that originate from the spinal cor
Stretch reflex
Reflex initiated by stretch receptors within a muscle
that results in contraction of the muscle to compensate for the
stretching.
Sulcus
Groove, especially shallow grooves in the
cerebral cortex.
Sympathetic nervous
system
best known for its role in responding to dangerous or stressful situations. In these situations, your sympathetic nervous system activates to speed up your heart rate, deliver more blood to areas of your body that need more oxygen or other responses to help your get out of danger.
Synapse
The junction between two neurons or between a neuron
and another target cell.
Synaptic cleft
Physical gap between two communicating neurons
or between a neuron and its target cell.
Synaptic end bulb
Button at the end of the axon that releases the
neurotransmitter; also called synaptic knob or terminal bouton.
Synaptic knob
synaptic end bulb
Synaptic transmission
The continuation of the nerve impulse
across the synapse from one neuron to another or from one
neuron to its target cell.
Target
An organ or tissue that responds to a particular hormone.
Telodendron
The branched end of an axon; each branch terminates in a neurotransmitter-filled synaptic end bulb.
Terminal bouton
Button at the end of the axon that releases the
neurotransmitter; also called the synaptic end bulb or synaptic
knob.
Thoracolumbar
system
The sympathetic division of the autonomic nervous system influences the various organ systems of the body through connections emerging from the thoracic and upper lumbar spinal cord
Threshold
The required level of stimulation, or degree of change
in a cell’s electrical potential, necessary to initiate an action
potential
Threshold stimulus
The minimum stimulus that will generate a
nerve impulse
Ventral horn
The area of the spinal cord’s gray matter “butterfly”
where the neuronsthat transmit motor(efferent) nerve impulses
to the spinal nerves are located.
Ventral nerve root
The branch off each side of the spinal cord
between each pair of adjacent vertebrae that conducts motor
impulses from the spinal cord to effectors in the periphery of
the body
White matter
Myelinated axons in the CNS
Withdrawal reflex
Reflex arc in which a painful stimulus on the
skin causes contraction of the affected limb; also called the flexor
reflex.
