Nervous System Flashcards
Acetylcholine
- Neurotransmitter used in the preganglion neuron in both the sympathetic and parasympathetic nervous systems
- Associated with somatic nerves and parasympathetic nervous system effects
- Has a stimulatory effect in GI tract, increases secretions and muscle contractions in the esophagus, stomach, ruminant forestomachs, intenstine, and colon
Acetylcholinesterase
Enzyme that breaks down acetylcholine
Adrenergic Neurons
Neurons that secrete catecholamines (i.e. norepi) as their neurotransmitter
Afferent
Directional terms meaning toward some reference point
Afferent Nerve
Nerve that carries impulses toward the CNS
All-or-Nothing Principle
Principle that an individual muscle fiber either contracts completely or not at all
Alpha 1-adrenergic Receptors
Receptors associated with the sympathetic nervous system response that cause vasoconstriction when stimulated by catecholamines
Anesthesia
Complete loss of sensation
Antiparasitic drug
Drug that kills parasites
Arachnoid
Delicate, weblike layer of the meninges between the dura mater and pia mater
Autonomic Nervous System
- Part of the nervous system that controls smooth muscle, cardiac muscle, or endocrine glands automatically without conscious control.
- Has both motor and sensory branches
Beta 1-Adrenergic Receptors
Receptors associated with the sympathetic nervous system that cause an increase in rate and force of contraction of the heart when stimulated by catecholamines
Beta 2-Adrenergic Receptors
Receptors associated with the sympathetic nervous system that cause dilation of bronchioles and vasodilation of some blood vessels when stimulated by catecholamines
Blood-Brain Barrier
- Functional barrier between the capillaries in the brain and the nervous tissue
- Composed of glial cells and unfenestrated capillaries
Brainstem
- Connection between the spinal cord and the rest of the brain
- Composed of the medulla oblongata, the pons, and midbrain
- Involves in autonomic control of heart, respiration, blood vessel diameter, swallowing, and vomiting
Catecholamines
Group of neurotransmitters that include norepi, epi, dopamine, etc.
Central Canal
Small diameter canal in the center of the spinal cord that is continuous with the ventricles of the brain and that is filled with cerebrospinal fluid
Cerebellum
- Second largest component of the brain
2. Allows the body to have coordinated movement, balance, posture, and complex reflexes
Cerebral Cortex
Gray matter that makes up the outer layer of the cerebrum
Cerebral Hemispheres
Two halves 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
- Portion of the brain responsible for ‘higher order’ behaviors (i.e. learning, awareness, etc.)
- Receives and interprets sensory info, initiates conscious nerve impulses to skeletal muscles, and integrates neuron activity that is associated with communication, expression of emotion, learning, memory, recall, etc.
Cholinergic Neurons
Neurons that secrete acetylcholine as their neurotransmitter
Cholinergic receptor
- Receptors for acetylcholine
2. Muscarinic or Nicotinic receptors
Conduction of the Action Potential
Another name for nerve impulse
Contralateral Reflex
Reflexes that are initiated on one side of the body and travel to the opposite side to produce their effect
Contrast Radiography
Rads taken after a contrast medium has been introduced to the body to make organs/structures more visible on the image
Corpus Callosum
White fibers that connects and provide communication between the two cerebral hemispheres
Cranial Nerves
- 12 pairs of nerves originating directly from the brain
2. May be sensory, motor, or mixed
Cranial-Sacral System
‘Parasympathetic Nervous System’
Crossed Extensor Reflex
Reflex initiated by a stimulation of a limb that results in extension of the limb on the other side of the body
Depolarization
- Reduction in the voltage across a neuron or muscle cell membrane from its normal polarized state (resting membrane potential)
- Results in an action potential (nerve impulse) in a neuron or a contraction initiative in a muscle cell
Diencephalon
- Nervous system passageway between the primitive brainstem and the cerebrum
- Contains the thalamus, hypothalamus, and pituitary
Dopamine
A catecholamine neurotransmitter
Dorsal Horn
Area of the spinal cord’s gray matter “butterfly” where the neurons that send afferent nerve impulses to the brain or spinal cord are located
Dorsal Nerve Root
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
Thick outermost layer of the meninges that covers the brain and spinal cord and is considered to be the toughest part of the meninges
Effector Cell
A cell that carries out some action when stimulated by a nerve impulse
Efferent
Direction terms meaning away from some reference point
Efferent Nerve
Nerve that Carrie’s impulses away from the CNS
Enzyme
- Specialized globular protein that carries out or speeds up chemical reactions in the body by acting as a catalyst and lowering the temp necessary for the reaction to take place
- Specific enzyme are exclusive to specific reactions
- They are never changes or used up in a reaction that may affect
Epidural Anesthesia
Admin of anesthetic agents into the space between the dura mater and the surrounding bone of the vertebrae
Excitatory Neurotransmitters
Neurotransmitters that cause excitation or depolarization of other neurons or target tissues
Fenestrations
Small openings in the walls of glomerular capillaries that allow certain molecules to leave that would normally be too big to escape
Fissures
Deep grooves in the cerebral cortex
GABA
- Gamma-aminobutyric acid
2. Inhibitory neurotransmitter
Ganglion/Ganglia
Cluster of neuron cell bodies outside the CNS
General Anesthesia
Complete loss of sensory perception accompanied by loss of consciousness
Glial Cells
Cells in the nervous system that support and protect neurons
Glycine
Inhibitory neurotransmitter found in the spinal cord
Gray Matter
Part of the CNS made up of neuron cell bodies
Gyrus/Gyri
Folds that provide the wrinkles appearance of the surface of the cerebral hemispheres
Hypermetria
A condition in which voluntary movements become jerky and exaggerated
Hyperreflexive
Reflex response that is more pronounced than normal
Hyporeflexive
Reflex response that is less pronounced than normal
Hypothalamus
Portion of the diencephalon that has extensive links to the brain and pituitary gland and functions as a bridge between the nervous and endocrine systems
Inhibitory Neurotransmitters
Neurotransmitters that depress or decrease depolarization of other neurons or target tissues
Interneuron
A short neuron that connects two other neurons, and is usually mentioned in the context of the reflex arc
Ipsilateral Reflex
When the reflex stimulus and response are on the same side of the body
Ivermectin
Antiparasitic drug that works by interfering with parasites’ nervous and muscular systems functioning, which paralyzes and kills them
Lobe
Different divisions of the cerebral hemispheres that specialize in certain functions and are separated by sulci
Local Anesthesia
Loss of sensation from a localized area of the body
Longitudinal Fissure
Prominent groove that divides the cerebrum into right and left cerebral hemispheres
Medulla Oblingata
Part of the brainstem just above the spinal cord
Meninges
- Set of connective tissues that surround the brain and spinal cord
- Has three layers (dura mater, arachnoid, pia mater)
Midbrain
“Mesencephalon”
Mixed Nerve
Nerve made up of both sensory nerve fibers and motor nerve fibers
Motor Nerve
Nerve that carries efferent nerve impulses to muscles and tissues
Motor Neuron
A neuron carrying impulses from the CNS to a peripheral effector organ or muscle
Muscarinic Receptor
A type of Cholinergic receptor that binds with acetylcholine in the parasympathetic nervous system
Muscle Spindle
Sensory organ located within muscle that detects stretch of the muscle
Myelin
- Fatty substance that covers some axons of neurons
- Appears white
- Makes up “white matter” of the brain and spinal cord
Myelin Sheath
Cell membrane of glial cells wrapped around an axon that increases the speed of impulse conduction along the axon
Myelography
Contrast study of the subarachnoid space to better visualize the outline of the spinal cord
Nerve Impulse
Wave of cell membrane depolarization that travels from the point of stimulus down the length of a nerve cell process
Neurotransmitter
A chemical released be the presynaptic neuron that diffuses across the synaptic cleft, binds with the receptor on the postsynaptic membrane, and stimulates or inhibits the postsynaptic neuron.
Nicotinic Receptor
Type of Cholinergic receptor that binds with acetylcholine
Nodes of Ranvier
Myelin gaps in the covering of the axon between Schwann cells that are involved in rapid conduction of nerve impulses along the axon
Norepinephrine
Hormone secreted by the medulla of the adrenal gland under stimulation by the sympathetic nervous system that produces the fight-or-flight response
Nuceli
Clusters of neuron cell bodies within the CNS
Oligodendrocytes
Glial cells in the brain and spinal cord whose cell 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
Parasympathetic Nervous System
- Part of autonomic nervous system that’s responsible for rest-and-restore response
- “Craniosacral system”
Peripheral Nervous System (PNS)
Nerves outside the CNS (brain and spinal cord)
Pia Mater
Innermost layer of the meninges
Pituitary Gland
- Master endocrine gland
- Pea-sized endocrine gland located at the base of the brain that is made up of the anterior and posterior pituitary gland
- Anterior pituitary gland produces seven known hormones
- Posterior pituitary gland stores and releases two hormones from the hypothalamus
Pons
Part of the brainstem located just rostral to the medulla oblongata
Postganglionic Neuron
- The second of two neurons that make up the nerves of the autonomic nervous system
- Originates from a ganglion and carries the impulse from its target organ or tissue
Postsynaptic Neurom
Neuron that contains receptors to a neurotransmitter, that causes depolarization or inhibition of depolarization of the neuron when the neurotransmitter binds
Preganglionic Neuron
The first of two neurons that make up the nerves of the autonomic nervous system
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 pupils in both eyes constrict
Receptor
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
Composed of the sensory receptor, sensory neuron, interneurons, motor neurons, and target tissue or organ involved with a stimulus and reflex response
Refractory Period
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
The electric charge of some cells at rest, caused by differing concentrations of ions inside and outside the cell membrane
Resting State
- State of the neuron before stimulation
2. When more sodium ions are outside the cell membrane than inside, and more potassium ions are inside the cell
Saltatory Conduction
Skipping the depolarization wave in a myelinated axon from one node of Ranvier to another
Schwann Cells
Glial cells associated with peripheral nerves whose cellular membrane forms the myelin sheath for axons in the PNS
Sodium-potassium Pump
Active transport molecule that moves sodium molecules out of the neuron and potassium molecules into the neuron to maintain the resting state
Soma
- Cell body of a neuron
2. “Perikaryon”
Somatic Nervous System
- Conscious or voluntary nervous system controlling skeletal muscle
- Somatic motor function = efferent
- Somatic sensory function = afferent
Somatic Reflex
A reflex resulting in the stimulation or inhibition of skeletal muscle contraction
Stretch Reflex
Reflex initiated by stretch receptors within a muscle that results in contraction of the muscle to compensate for stretching
Sulcus/Sulci
Shallow grooves in the cerebral cortex
Sympathetic Ganglion Chain
Series of ganglia located outside the thoracolumbar area of the spinal column and associated with the sympathetic nervous system
Sympathetic Nervous System
- Part of the autonomic nervous system
- Responsible for fight-or-flight response
- “Thoracolumbar system”
Synapse
Junction between two neurons or between a neuron and a 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
- “Synaptic knob,” “Terminal Bouton”
Synaptic Transmission
Continuation of the nerve impulse across the synapse from one neuron to another or from one neuron to its target cell
Synergist
- Something that aids in the action of something else
2. A synergistic muscle contracts at the same time as a prime mover and assists it in carrying out its action
Target
An organ or tissue that responds to a particular hormone
Telodendron
Branched end of an axon in which each branch ends in a neurotransmitter-filled synaptic end bulb
Terminal Bouton
Button at the end of an axon that releases neurotransmitters
Thalamus
Part of the diencephalon that acts as a relay station for regulating sensory impulses to the cerebrum
Thoracolumbar System
- Sympathetic nervous system
Threshold
Required level of stimulation necessary to initiate an action potential
Threshold Stimulus
Minimum stimulus that will generate a nerve impulse
Ventral Horn
Area of the spinal cord’s gray matter “butterfly” where the neurons that transmit efferent nerve impulses to the spinal nerves are located
Ventral Nerve Root
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
Wave of Depolarization
- The opening of sodium channels, starting at the point of stimulus and continuing down the length of the neuron to the end of the axon
- “Nerve impulse”
White Matter
Myelinated axons in the CNS
Withdrawal Reflex
- Reflex arc in which a painful stimulus in the skin causes contraction of the affected limb
- “Flexor reflex”
Cranial Nerve I
- “Olfactory”
- Sensory
- Aids in smell
Cranial Nerve II
- “Optic”
- Sensory
- Aids in vision
Cranial Nerve III
- “Oculomotor”
- Motor
- Aids in eye movement, pupil size, focusing lens
Cranial Nerve IV
- “Trochlear”
- Motor
- Aids in eye movement
Cranial Nerve V
- “Trigeminal”
- Sensory & motor
- Aids in sensations from head and teeth, chewing
Cranial Nerve VI
- “Abducent”
- Motor
- Aids in eye movement
Cranial Nerve VII
- “Facial”
- Sensory & motor
- Aids in face and scalp movement, salivation, tears, and taste
Cranial Nerve VIII
- “Vestibulocochlear”
- Sensory
- Aids in balance and hearing
Cranial Nerve IX
- “Glossopharyngeal”
- Sensory & motor
- Aids in tongue movement, swallowing, salivation, taste
Cranial Nerve X
- “Vagus”
- Sensory & motor
- Aids in sensory from GI tract and respiratory tree
- Aids in motor to larynx, pharynx, parasympathetic system
- Aids in motor to abdominal and thoracic organs
Cranial Nerve XI
- “Accessory”
- Motor
- Aids in head movement, accessory motor with vagus
Cranial Nerve XII
- “Hypoglossal”
- Motor
- Aids in tongue movement
