Nervous System Chapter 12, 15 Flashcards
What plays the dominant role for:
-Integration
-Coordination
-Association responses to internal and external demand
The Nervous System
The Nervous System is responsible for what 4 things?
-Perceptions
-Behaviors
-Memories
-Initiating all voluntary movements
(Major structures of the nervous system)
What is:
-Housed within the skull and contains approximately 85 billion neurons
The brain
(Major structures of the nervous system)
What are:
-Twelve pair numbered I - XII
Cranial Nerves
(Major structures of the nervous system)
What is:
-A bundle containing hundreds to thousands of axons including connective tissue and blood vessels
A Nerve
(Major structures of the nervous system)
What is:
-In a nerve
-(Axons and Dendrites)
Nerve Fibers
Nerve fibers may be ________? (4)
-Sensory
-Motor
-Somatic
-Autonomic
(Major structures of the nervous system)
What is:
-Contained within the spinal column and connected to the brain through the foramen magnum
Spinal Cord
(Major structures of the nervous system)
What are:
- Thrity- one pairs that exit from the spinal cord
Spinal Nerves
(Major structures of the nervous system)
What are:
-Small masses of nervous tissue made up primarily of neuron cell bodies
Ganglia
What are located outside the brain and spinal cord?
Ganglia
Which function of the nervous system is:
-To sense changes in the internal and external environment through sensory receptors?
Sensory Function
Which neurons serve the Sensory function?
Sensory (afferent) Neurons
Which function of the nervous system is:
-To analyze the sensory information
-Store some aspects
-Make decisions regarding appropriate behaviors
Integrative Function
Which neurons serve the Integrative function?
-Association or Interneurons
Which function of the nervous system is:
-To respond to stimuli by initiating action
Motor Function
Which neurons serve the Motor function?
Motor (efferent) neurons
(Organization of the Nervous System)
What 2 parts of the body that are in the Central Nervous System? (CNS)
-Brain (encephalon)
-Spinal cord (Medulla spinalis)
(Organization of the Nervous System)
What 2 parts of the body that are in the Peripheral Nervous System? (PNS)
-Twelve pair of cranial nerves
-Thirty-one spinal nerve pairs
Which subdivision of the Peripheral Nervous System is:
-Incoming information to spinal cord and brain
Sensory division (afferent)
Which subdivision of the Peripheral Nervous System is:
-Outgoing information from spinal cord and brain
Motor Division (Efferent)
Which subdivision of the Motor division is:
-Efferent to skeletal muscle
Somatic nervous system (SNS)
Which subdivision of the Motor division is:
-Efferent to smooth muscle, cardiac muscle, and glands
Autonomic nervous system (ANS)
Somatic nervous system:
-Usually under voluntary control except in the case of ________ ________, and skeletal muscles involved in ________, _________, and ___________.
-Somatic reflexes
-Breathing, posture, reflexes
Somatic nervous system:
-A single neuron travels the entire distance to the ________.
Muscle
Somatic nervous system:
-The neurotransmitter released at the _______________ junction is ____________.
-Neuromuscular junction
-Acetylcholine
Which 2 subdivisions of the Autonomic nervous system:
-Supplies efferent to smooth muscle, cardiac muscle, and glands
-Sympathetic nervous system
-Parasympathetic nervous system
Which subdivision of the Autonomic nervous system:
-Supplies efferent to smooth muscle and glands of G-I tract
Enteric nervous system
The entire nervous system can operate ___________ of the sympathetic and parasympathetic divisions but is __________ on them for proper functioning of the _________ system.
-Independently
-Dependent
-Digestive
(Autonomic Nervous System)
-Which 2 efferent neurons are utilized to reach the muscle or gland?
-Preganglionic (first order neuron)
-Postganglionic (second order neuron)
(Autonomic Nervous System)
Autonomic neurons release ____________, except postganglionic neurons of the sympathetic division which release _________________.
-Acetylcholine
-Norepinephrine
(Autonomic Nervous System)
-Some first order neurons of the sympathetic division extend to __________ cells in the _________ _________ (center of adrenal gland) instead of a ganglion and release ____________.
-Chromaffin cells
-Adrenal medulla
-Acetylcholine
(Autonomic Nervous System)
-Chomaffin cells release __________ and _____________ into the blood.
-Epinephrine
-Norepinephrine
What is found in:
-Cranial nerves III, VII, IX, X
-Sacral nerves 2,3,4
-“Craniosacral division”
Parasympathetic Division
Which acronym is used for the Parasympathetic division?
Rest - and - Digest
What is found in:
-At T1 - L2 maybe L3 (Rare)
-“Thoracolumbar division”
Sympathetic Division
Which acronym is used for the Sympathetic division?
Fight - or - Flight
Parasympathetic vs. Sympathetic often have _______ effects on the same organ/muscle.
Opposite
What parasympathetic effects would happen to an organ/muscle? (3)
-Slows heart rate
-Speeds peristalsis
-Constricts the pupil
What sympathetic effects would happen to an organ/muscle? (3)
-Speeds heart rate
-Slows peristalsis
-Dilates the pupil
(Sensory Division of Nervous System)
Which subdivision is:
-Tactile, thermal, pain and proprioception
-Perception of body position
-Conscious and Unconscious
Somatic senses
(Sensory Division of Nervous System)
Which subdivision:
-Monitors internal organs of the cardiovascular, respiratory, digestive, urinary and reproductive systems
Visceral senses
(Sensory Division of Nervous System)
Which subdivision is:
-Smell, taste, vision, hearing, and equilibrium
Special senses
What two principal types of cells are in the nervous system?
-Neurons
-Neuroglia
Which cells support, nourish and protect the neurons?
Neuroglia
Which cells conduct nerve impulses from one part of the body to another?
Neurons
Neurons carry electrical impulses in the form of ________ ___________.
Action potentials
Neurons may be ________ or ________ or _______________.
-Motor
-Sensory
-Interneurons
(Structure of a Neuron)
What is:
- A process conducting an impulse or carrying a charge towards the cell body.
Dendrites
(Structure of a Neuron)
What is:
-A single process of a neuron conducting an impulse away from the cell body towards the telodendria
Axon
(Structure of a Neuron)
What is:
-The gradual boundary between the cell body and the axon
Hillock
(Structure of a Neuron)
What is:
- The plasma membrane of an axon.
Axolemma
(Structure of a Neuron)
What is:
- A cytoplasm of an axon
Axoplasm
(Structure of a Neuron)
What are:
- Bulb shaped structures at the ends of some telodendra
Synaptic end bulbs or Axon terminals
(Structure of a Neuron)
What:
- Contains the nucleus
Cell body (Soma or Perikaryon)
(Structural classification of Neurons)
What has:
-Several dendrites & one axon
-Most common cell type
Multipolar
(Structural classification of Neurons)
What has:
-One main dendrite & one axon
Bipolar neurons
Where are Bipolar neurons found? (3)
-Retina
-Inner ear
-Olfactory
(Structural classification of Neurons)
What has:
-One process only
-Dendrites and axons fused together
-Always sensory neurons
Unipolar neurons
Types of CNS Neuroglia (Glial cells)
What type of Glial cells are:
-Most numerous cell of the CNS
-Provide pathway to deliver nutrients to neurons from blood vessels
Astrocytes
Which type of Glial cells:
-Help form blood-brain barrier
Astrocytes
Types of CNS Neuroglia (Glial cells)
What type of Glial cells:
-Form myelin sheaths in the CNS
Oligodendrocytes
Types of CNS Neuroglia (Glial cells)
What type of Glial cells are:
-Phagocytic function engulfing invading microbes and cleaning up cellular debris
Microglia
Types of CNS Neuroglia (Glial cells)
What type of Glial cells:
-Line central canal of spinal cord and brain ventricles
Ependymal
Which type of Glial cells form cerebrospinal fluid?
Ependymal
Types of CNS Neuroglia (Glial cells)
What type of Glial cells:
-Forms myelin sheath in the PNS
Schwann cells (Neurolemmocyte)
Types of CNS Neuroglia (Glial cells)
What type of Glial cells are:
-Flat cells surrounding neuronal cell bodies in peripheral ganglia
-Structural support of neurons in the PNS ganglia
Satellite cells
What is the:
-Covering over many nerve axons in the CNS (Oligodendrocyte) and PNS (Schwann cell)
Myelin sheath
There is no myelin over the ______ __________, cell body or _________.
-Axon terminals
-Hillock
What:
-Increases the speed of nerve impulses and insulates and maintains the nerve fiber
Myelin
How many mph does myelin increase the speed of nerve impulses?
1 - 270 mph
What are:
-Cells that surround nerve fibers and form myelin sheath in PNS
-Located on all PNS nerve fibers although not all fibers are myelinated
Schwann cells
(Schwann cells)
What are:
-Gaps between segments of myelin sheath
Nodes of Ranvier
What is another name for the Nodes of Ranvier
Neurofibral node
(Myelin Formation)
(1) In order to form myelin, the ________ cells wrap around the ______ _______ many times.
-Schwann
-Nerve fibers
(Myelin Formation)
(2) The nucleus and __________ are pushed to the outside.
-Cytoplasm
(Myelin Formation)
(3) The inner portion consisting of up to _____ layers of Schwann cell membrane is the __________ __________.
-100
-Myelin sheath
(Myelin Formation)
(4) The outer portion is called the ___________ (cytoplasm & nucleus)
-Neurolemma
(Electrical Signals in Neurons)
Which Electrical signal is:
-Used for short distance communication
-Travel through dendrites and cell bodies
-May be + (depolarizing) or - (hyperpolarizing) voltage change
Graded potentials
(Electrical Signals in Neurons)
Which Electrical signal is:
-Used for long distance communication
-Travel the length of axons
-Always begin with depolarization
Action potentials
Which Electrical signal:
-Must occur to depolarize the neuron to threshold before action potentials can occur
Graded potentials
Which Electrical signal:
-Occurs in a sensory receptor of the skin when you touch a pen
Graded potentials
Graded potentials trigger an ______ _______ in a sensory neuron which travels to the _____ causing a release of a neurotransmitter at a synapse with an ___________.
-Action potential
-CNS
-Interneuron
Which Electrical signal happens when:
-A voltage change which travels along a nerve or muscle fiber
Action potential
What occurs when:
-The inside of a neuron cell membrane has a relative negative charge as compared to the outside.
Resting Membrane Potential
(Resting Membrane Potential)
-This is the result of a small build up of _________ _____ on the inside of the membrane and ________ _____ on the outside.
-Negative ions
-Positive ions
What is the typical RMP?
-70 mv
(Action Potential)
-During ____________ phase of AP, the cell membrane becomes permeable to ___ allowing ___ to enter cell causing inside of cell to become less _________.
-Depolarizing
-Na+
-Na+
-Negative
What phase of Action Potential:
-Na+ permeability falls to resting level
-K+ permeability increases, and cell becomes more permeable to K+ than at rest, allowing K+ to exit cell causing inside of cell to become more negative
Repolarizing phase
(Action Potential)
-Whenever the inside of the cell is less negative than the resting potential, the cell is said to be ___________.
Depolarized
(Action Potential)
-If the inside of the cell is more negative than the resting potential, it is ______________.
Hyperpolarized
(Action Potential)
-The cell is hyperpolarized during the _____ - ___________ _______.
After- hyperpolarizing phase
(Action Potential)
-Whenever a cell is depolarized to a certain level, an ________ __________ occurs.
Action Potential
(Action Potential)
What is the:
-Smallest depolarization that can cause an action potential
(Word and number)
Threshold
-55 mv
(Action Potential)
-Permeability changes during the action potential are caused by _______ in the ___________ opening and closing.
-Pores
-Membrane
What occurs when:
-Voltage -gated Na+ channel is closed
-K+ channel is closed
Resting Cell Membrane
Depolarizing cell to threshold causes:
- Immediate ______ of v-g Na+ channel
- Na+ inflow causes ___________ _____ of AP.
-Opening
-Depolarization phase
-Closing of Na+ channel
-Opening of K+ channel activation gate allowing outflow of K+
Together these cause…?
Repolarization phase
(Repolarization phase)
-When cell has repolarized to near resting state:
-_______ gate Na+ channel is closed
-K+ continues to ____ _____ as K+ is closing
-Voltage
-Flow out
What happens when:
-Voltage gated K+ channel activation gate closes
-Local anesthesia keeps v-g Na+ channels from opening
Return to resting state
What happens when:
-Stimulate a cell 2 times
-First stimulus if greater than threshold always causes an AP
Refractory period
What is the:
-Period of time after first stimulus when second stimulus, no matter how large, can’t cause a second AP.
Absolute refractory period
What is the:
-Period of time during which a second AP can be initiated, but only by a larger than threshold stimulus.
Relative refractory period
What is another name for a:
Larger than threshold stimulus
Suprathreshold
Once depolarization has occurred, we say a nerve impulse is initiated, this impulse must be __________ along the neuron.
Propagated (Impulse conduction)
What:
-Occurs on unmyelinated nerve fibers or muscle fibers
Continuous Conduction
What occurs when:
-A nerve impulse that is generated at one point usually excites adjacent portions of the membrane, causing the impulse to be propagated.
Continuous conduction
What occurs:
-On myelinated nerves
(1)-Action potential can only occur at the nodes of Ranvier due to the insulating effects of myelin.
Saltatory Conduction
what occurs when:
(2) -Electrical current flows through surrounding extracellular fluid and also through axoplasm from node to node causing depolarization at each node.
-Therefore, the impulse jumps from node to node
Saltatory Conduction
What occurs:
-On myelinated nerves.
-AP occurs only at the nodes of Ranvier due to insulating effects of myelin.
-Electrical current flows through extracellular fluid and axoplasm from node to node causing depolarization at each node.
-The impulse jumps from node to node.
Saltatory conduction
All-or-None Principle:
-If a stimulus is strong enough to generate a _____ AP, the impulse is conducted along the entire neuron at a _______ and _________ strength for the existing condition.
-Nerve
-Constant and Maximum
What does this describe:
-Either the impulse is propagated along the entire length of the neuron at the same amplitude, or it doesn’t travel at all.
All-or-None principle
(Speed of Nerve Impulses)
What are:
-Myelinated
-12 - 130 meters/second
-Major sensory nerves
-Large motor nerves to skeletal muscles
A Fibers
Where are A Fibers involved?
-Where rapid response is vital
-Touch, pressure, heat, cold, position of joints
(Speed of Nerve Impulses)
What are:
-Medium size myelinated
-10 - 15 meters/second
-Autonomic efferent to autonomic ganglia
B Fibers
(Speed of Nerve Impulses)
What are:
-Small non-myelinated
-0.5 -2 meters/ second
-Autonomic efferents from autonomic ganglia to heart, smooth muscle and glands.
C Fibers
Which fibers have:
-Sensory from viscera to brain and spinal cord
B Fibers
Which fibers have:
-Pain, touch, pressure, heat and cold from skin, and pain impulses from viscera
C Fibers
What is a:
-Junction between 2 neurons
Synapses
A junction between 2 neurons may be:
Axon > _________
Axon > _________
Axon > _________
-Dendrite
-Axon hillock
-Cell body
What is the name for the junction:
Axon > Dendrite
Axodendritic
What is the name for the junction:
Axon > Axon hillock
Axoaxonic
What is the name for the junction:
Axon > Cell body
Axosomatic
What is:
-A nerve impulses travel from one cell to another through small, protein, tubular structures in gap junctions
Electrical Synapses
What are tubular structures in gap junctions called?
Connexons
Electrical synapses are faster than ________ synapses.
Chemical
-Presynaptic neuron
-Postsynaptic neuron
-Axon terminal
-Synaptic cleft
-Synaptic vesicle
-neurotransmitter receptor
Are components of what?
Components of a Chemical Synapse
(Chemical Synapses)
(1) Action potential conducted to tip of axon depolarizing the ____________ ________.
Presynaptic terminal
What is another name for the: Presynaptic Terminal
Synaptic end bulb
(Chemical Synapses)
(2) Terminal cell membrane permeable to Ca2+. Ca2+ _______ into presynaptic terminal.
Diffuses
(Chemical Synapses)
(3) Ca2+ attracts ________ __________ to the plasma membrane and neurotransmitter is released into _________ ______ by exocytosis.
-Synaptic vesicles
-Synaptic cleft
(Chemical Synapses)
(4) _____________ diffuses across synaptic cleft.
Transmitter
(Chemical Synapses)
(5) Two possibilities:
-Neurotransmitter may cause _____________ or _______________
-Depolarization (Excitatory graded potential)
-Hyperpolarization (Inhibitory graded potential)
(Chemical Synapses)
(6) Postsynaptic neuron is depolarized causing an __________ ___________ ________.
Excitatory postsynaptic potential (EPSP)
(Chemical Synapses)
(7) Postsynaptic neuron is hyperpolarized causing inhibition at postsynaptic membrane called an __________ ____________ _________.
Inhibitory postsynaptic potential (IPSP)
Does IPSP or EPSP:
-Increases permeability to CL- and CL- flows into the cell or less commonly an increased permeability to K+ (flows out)
IPSP
Does IPSP or EPSP:
-Increases permeability to positive ions. (Na+ main effect flows in)
EPSP
Is IPSP or EPSP:
-Hyperpolarizing
IPSP
Is IPSP or EPSP:
Depolarizing
EPSP
Does IPSP or EPSP:
-Push inside of cell away from threshold
IPSP
Does IPSP or EPSP:
-Tend to depolarize cell toward threshold
EPSP
EPSP’s cause an ____ in postsynaptic neurons through __________.
EPSP’s must be added to __________ cells to threshold.
-AP
-Summation
-Depolarize
What type of summation is:
-A single presynaptic end bulb firing two or more times in rapid succession.
Temporal Summation
What type of summation is:
-Several presynaptic end bulbs release their neurotransmitter on the same postsynaptic neuron at the same time
Spatial summation
(Neurotransmitters)
-Both _________ and _________ neurotransmitters are present in the ____ and ___; the same neurotransmitter may be ________ in some locations and _________ in others.
-Excitatory and Inhibitory
-CNS and PNS
-Excitatory
-Inhibitory
-Acetylcholine
-Glutamate
-Aspartate
-Gamma aminobutyric acid
-Glycine
-Norepinephrine
-Epinephrine
-Dopamine
Are all what?
Important neurotransmitters
Name as many Important neurotransmitters as you can. (8)
-Acetylcholine
-Glutamate
-Aspartate
-Gamma aminobutyric acid
-Glycine
-Norepinephrine
-Epinephrine
-Dopamine
(Small-Molecule Neurotransmitters)
What is:
-Released by many PNS neurons and some CNS
-Excitatory on NMJ but inhibitory at others (Slows heart rate)
Acetylcholine (ACh)
(Small-Molecule Neurotransmitters)
What is:
-Glutamate released by nearly all excitatory neurons in the brain
-GABA is inhibitory neurotransmitter for 1/3 of all brain synapses
Amino Acids
(Amino Acids)
________ is a GABA agonist - enhancing its inhibitory effect.
Valium
(Small-Molecule Neurotransmitters)
What are:
-Modified amino acids
Biogenic Amines
What are the 2 Biogenic Amines? (modified amino acids)
-Tyrosine
-Tryptophan
What:
-Regulates mood, dreaming, awakening from deep sleep
from Tyrosine?
Norepinephrine
What:
-Regulates skeletal muscle tone
from Tyrosine?
Dopamine
What:
-Control of mood, temperature regulation, and induction of sleep
from Tryptophan?
Serotonin
(Neuropeptides)
-What:
Enhances our perception of pain
Substance P
(Pain relief)
What has a:
-Pain relieving effect 200 times stronger than morphine
Enkephalins
Endorphins and dynorphins are examples of ….?
Opioid peptides
What is:
-The nervous systems ability to change in form and function based on experience throughout your life.
Plasticity (Neuroplasticity)
(Regeneration & Repair)
-Neurons have the ability to change its _________ contacts with other neurons including increased ___________ of __________. (Rewire its connections)
-Synaptic
-Branching of dendrities
Plasticity allows healthy parts of the ________ system to take over the function of areas that are ___________.
-Nervous
-Damaged
Plasticity can also occur as a result of ___________, ____________, and ____________ ____________.
Learning, Experience, and Memory formation
What is:
-The ability of neurons to replicate or repair themselves.
Regeneration
(Regeneration)
-PNS dendrites and myelinated axons have some limited ability to be ________ if the ____ ______ remains intact.
-Repaired
-Cell body
(Regeneration)
-Little or no ______ of CNS neurons occur after ________.
-Repair
-Damage
What disorder is:
-Destruction of the myelin sheath surrounding the neurons in the CNS
-Symptoms include:
-Numbness, tingling, weakness and visual problems
Multiple Sclerosis
What disorder is:
-Appears ages 20-40 and affects females 2x as often as males
-Autoimmune, no cause
-Myelin sheaths deteriorate to scleroses
-MRI reveal the plaques in the brain and spinal cord
Multiple Sclerosis
What disorder is:
-Short recurrent attacks of motor, sensory, or psychological functions
-Nonidentifiable cause in about half the people affected
Epilepsy
What disorder is:
-Seizures or periods of unusual behavior, sensations, and sometimes loss of awareness
-Causes: brain damage, tumors, strokes, infections, head trauma, possible genetic influences
Epilepsy
What disorder is:
-A deadly virus spread to people from the saliva of infected animals
-Virus spreads to the CNS
Rabies
What disorder is:
-An acute demyelinating disorder in which macrophages attack myelin in PNS neurons
-Autoimmune
-Exact cause isn’t known
Guillain-Barre syndrome
(Disorders of the Nervous System)
What disorder is:
-Numbness, tingling and weakness that leads to acute paralysis
-Appears days or weeks after a bacterial infection
-Recent surgery or immunization rarely trigger it
-Most recover completely or partially, 15% remain paralyzed
Guillain-Barre syndrome
What disorder is:
-A malignant tumor consisting of immature nerve cells (neuroblasts)
neuroblastoma
What disorder is:
-Most commonly occurs around adrenal glands
-most commonly affects children under the age of 5
Neuroblastoma
What disorder is:
-Digits become ischemic after exposure to cold or emotional stress
-Excessive sympathetic stimulation resulting in vasoconstriction of arterioles
Raynaud phenomenon
What disorder is:
-Digits may become cyanotic (appear blue) or blanch (appear white)
-Once the digits rewarm after exposure to cold, they may appear red due to arterioles dilating
Raynaud phenomenon
What disorder is:
-A disruption to sympathetic innervation to one side of the face
-Ptosis (drooping of eyelids), miosis (constricted pupil), anhidrosis (lack of sweating)
-Common causes are:
-Injury to neck, head or shoulder, tumor or disease affecting sympathetic pathway, inherited defect
Horner’s syndrome
What disorder is:
-Potentially life-threatening overreaction of the sympathetic nervous system in response to spinal cord injuries above the level of T6
Autonomic dysreflexia
What disorder is:
-Results when certain sensory inputs such as a full bladder, distended or irritated bowel are unable to ascend the spinal cord
-Leads to elevated blood pressure and slower heart rate
-Treatment involves identifying the cause and applying appropriate intervention
Autonomic dysreflexia
What disorder is:
-After limb amputation, sensations such as pain, itching, pressure or tingling may still be felt as if the limb was still there
Phantom limb pain
What is:
Loss of voluntary muscular fucntion
Paralysis
What type of paralysis is:
-Atrophy and loss of muscle tone and deep tendon reflexes(hypo-reflexive)
-Indicates a lower motor neuron lesion (Damage to peripheral nervous system)
Flaccid paralysis
What type of paralysis is:
-Muscles are spastic or rigid
-Increased deep tendon reflexes (Hyper-reflexive) and a positive Babinski sign
-indicates an upper motor neuron lesion (Damage to the central nervous system)
Spastic paralysis
What occurs when:
-The great toe extends, and the other toes abduct in response to the sole of the foot being firmly stroked
Babinski sign
ATP and other purines:
-ADP, AMP & Adenosine
Are what?
Excitatory in both CNS and PNS and are Small-Molecule Neurotransmitters
What are:
-Formed from amino acid arginine by an enzyme
-Formed on demand and acts immediately
-First recognized as vasodilator that helps lower blood pressure
Gases- Nitric oxide or Nitrous Oxide
(Action Potential)
-When the voltage changes from negative to positive, it’s considered ____________
Depolarization
(Action Potential)
-When the voltage changes from positive to negative, it’s considered ______________
Repolarization
(Action Potential)
-When the voltage goes more negative than resting membrane potential, it’s considered _______________
Hyperpolarization
