Test 2 Study Guide Flashcards
The ability of a neuron to transmit charge through its cytoplasm is called called cable properties and is very?
poor
What poison inhibits glycine receptors?
strychine
Which of the following are natural analgesics? Dynorphins endorphins enkephalins All apply
All apply
Which of the following are not true of EPSPs?
a-they are inhibited by neurotransmitters
b-they are capable of summation
c-they have a refractory period
d-they are graded responses
They have a refractory period
The most abundant neuropeptide in the brain is?
neuropeptide Y
What is the function of dendrites?
transmites action potientials from cell body
Blocking ___________ channels would prevent depolarization.
Na+
Birds and fish have comparitively larger _____________ to account for the the complex movements they utilize daily
cerebellum
Which drug is utilized for ADD/ADHD and is not typically an issue when it comes to susbstance abuse as it deals closely with the neurotransmitter norepinephrine?
Straterra
All of the following will inhibit the regeneration of a cut axon EXCEPT
a) death recepetors
b) nogo protiens
c) schwann cells
d) glial scars
Schwann cells
As the intensity of a stimula increases, more axons become activated. This is called
recruitment
What type of proteins are present in gap junctions that form water-filled channels between neurons?
connexins
What type of neurons are pseudounipolar and carry impulses towards the CNS?
sensory neurons
The _________ dopamine system may be involved in emotinal reward and drug addiction
mesolimbic
What amino acid are dopamine, norephinerine, and epinephrine derived from?
tyrosine
Which type of cell lines the ventricles of the brain and help produce cerebrospinal fluid
ependymal cells
What is present at the axon hillock that allows the production of action potientials?
Ligand-gated channels
What type of proteins are present at chemical synapses to ensure the close proximity of the presynaptic and postsynaptic membranes?
cell-adhesion molecules
Which division of the nervous system innervates involuntary effectors?
autonomic nervous system
The myelin sheaths of CNS neurons are produced by?
oligodendrocytes
Nerve gad and cockroach poison are similar in that they cause the generation of uncontrolled action potientals which leads to uncontrolled muscle contractions and eventual death. How do these poisons work?
Blocking acetylcholinersterase
Action potential transmission in the PNS is decreased if which cells are damaged?
Schwann cells
The regulatory subunits in the action of the monomaine neurotranmitters prefers to bond to ________ when present
cAMP
Muscarinic Ach receports act through ________” activation of K+ channels
G-proteins
Receptors that require the use of secondary messengers are known as __________.
metabotropic
Neurotransmitter release would be inhibited by?
blocking Ca+ voltage gates channels in the terminal buttons
Which type of cell of the CNS is phagocytotic yet also produces free-radicals?
microgia
What action produces an IPSP on the postsynaptic membrane?
opening of Cl- channels into the neuron
In a myelinated axon, Na+ channels are
concentrated on the nodes of Ranvier
Which of the following will NOT lead to the release of endogenous opiods?
a) running hard for 5 miles
b) taking a BIOL 460 exam
c) breaking your leg in a car wreck
d) eating pepper that are very got
b) taking a bio 460 exam
The action of ________ phosphorylates various enzymes which will turn them on and off as well as open and close ion chanels.
protein kinase
What structure is found around PNS axons that is NOT found around CNS axons?
neurilemma
Which of the following is NOT broken down by the COMT in the post-synaptic cell?
a) dopamine
b) epinephrine
c) norephinephrine
d) serotonin
serotonin
Action potentials would be conducted most rapidly by?
a 40mm diameter myelinated axon
Monoamine oxidase (MAO) breaks down neurotransmittesr in the presynaptic cell
dopamine
serotonin
norepineephrine
What is NOT true of the relative refractory period?
a-Na+ channels are inactivated
b-many Na+ channels are returning to a closed state
c-K+ is moving out of the axon through its open channels
d-a strong stimulus could cause a depolarization
Na+ channels are inactivated
Muscarinic ACh receptors are found in?
glands, cardiac muscle, and smooth muscle
Enhancing the excitability of a synpase by continual use so that transmisson is favored along certain pathways is called?
long-term potentiation
Parkinson’s disease occurs due to issues with _________ neurons.
dopaminergic neurons
Synaptic vesicles are docked to the plasma membrane of the axon terminal by a protein complex called?
SNARE
The average resting membrane potiential of an axon is?
-70mv
Which G-protein subunit binds GDP?
alpha subunit
Curcare toxin inhibits the nictinic cholinergic receptors causing?
Flaccid paralysis
Which region of the brain contains the hypothalamus?
dicencephalon
T/F
Somatic motor neurons innervate involuntary effects
False
T/F
The blood/brain barrier may prevent medications from reaching brain tissue
True
T/F
Endogenous opioids transmit impulses of pain
False
T/F
The majority of the limbic system is located in the myelencephalon
False
T/F
The nicotinic ACh receptor is a ligand-gated channel
True
T/F
The threshold value for an action potential of a neuron is +30mv
False
T/F
Glycine and GABA stimulate opening of CL-channels
True
T/F
Most brain tumors in adults are found within neurons
False
T/F
Retrograde axonal transport may be responsible for movement of herpes virus, rabies virus, and tetanus toxin from nerve terminals to the cell body
True
T/F
Serotonin is produced in the cell bodies of the mesencephalon, specifically the tegmentum
False
Resting membrane poteintal is when a cell is?
is NOT producing any impulses
The cell membrane is most permeable to?
potassium ions
The resting membrane poteintial is ?
-70mv
Cell signalling is how cells?
communicate with each other
What are gap junctions?
adjacent cells to pass ions and regulatory molecules through channel, connecting the two cytoplasms of different cells
When cells within a organ secrete molecules that diffuse across the extra-cellular space to nearby target cells it is called?
paracrine signalling
When neurons secrete neurotransmitters across synapses to target cells it is called?
synaptic
When glands secrete hormones into the bloodstream and only cells that are target cells respond it is called?
Endocrine signalling
What are specific protiens that will react to paracrine regulators, NTS or specific hormones are called?
receptor protiens
Where are receptor proteins located?
on cell membrane, inside the cell, and sometimes insides the nucleus
What are some examples of receptor proteins in the nucleus?
Steroid, thyroid and NO
What are some examples of receptor proteins on the cell membrane?
epinephrine
Acetylcholine
insulin
An example of a secondary messenger is?
Large molecules or polar molecules that bind to receptors on the membrane
Once a large or polar molecule is bound to the cell membrane, a secondary messenger will?
be sent into the cell or formed within the cell and complete the job
_____________ ____________= signal transduction pathway
secondary messengers
What is cAMP?
Cyclic adensoine mono-phosphate
cAMP is produced from?
ATP
G-proteins are comprised of?
3 protein subunits
Alpha, Beta and Delta
When a g-protein receptor is unbound (inactive) all subunits will?
aggregate together with receptor and alpha beinds to GDP
When a regulatory protein molecule binds to a receptor what occurs with the g-protein?
Alpha dissacoiates from beta and gamma, and either alpha or beta/gamma moves through cell membrane and binds to an effector protein (enzyme or ion channels
After effector protein is activated, the alpha subunit does what (g-protein)?
alpha splits GTP into GDP and pi and reagreegates with beta and gamma unstimulated receptor
The CNS is made of?
The brain and spinal chord
The PNS is made of?
cranial nerves and Spinal nerves
What are neurons?
structural & function unit responds to both physical and chemical stimulus
What type of cell produce and conduct electrical impulses, release chemical regulators and enable preception of sensory learning, memory and control of muscles and glands?
Neurons
What function do neuroglial cells serve?
support
T/F Neuroglial cells divide by mitosis
true
What is the cause of cancer cells in nervous tissue?
neuroglial cells
Where are the nucleus and other organelles were macro molecules are located?
Neurons cell body
What are Nissil bodies?
Stacks of rough ER that synthesis membrane proteins
A group of neuron cell bodies in the CNS is called the?
nucleus
A group of neuron cell bodies in the PNS is called the?
ganglia
What are dendrites?
thin, branching cells that go from cytoplasm to cell body and typically receive signals
What are axons?
Conducts APs (Electrical impulses)
What size are axons?
They vary in size, 1mm to over 1M long
What is the axonal Hillock?
A enlarged portion of the axon near cell body
What is important to know about the axon hillock?
Action Potential starts here
What are axon collaterals?
Branches at the end of axons
What do axons commonly have?
myelin sheaths
The open spots in between the myelin sheaths are called?
nodes of Ranvier
Anterograde axonal transport is?
From cell body to axon collaterals
Retrograde axonal transport is?
From axon to cell body
What is an example of retrograde axonal transport?
Herpes
What are the fast components of axonal transport?
Membranous vessicles neurotransmitters that move at speeds of 50-400mm/day
What are the two slow componenets of axonal transport?
Tubules and Protiens (28mm/day)
What are the two major cateogories of functional nerves?
Sensory (afferent) and Motor (efferent) neurons
Sensory nerves?
send impulses into CNS from sensory receptors
Motor Nerves?
Send impulses from CNS to effectors (muscles and glands)
What are the different types of motor neurons?
Somatic and Autonomic
Somatic motor neurons?
contract under voluntary control
Autonomic motor neurons?
contract in-voluntary muscle, stimulate gland secretions
What are the two types of Autonomic motor neurons?
Sympathetic and Parasympathetic
Sympathetic autonomic motor neurons?
are responsible for an emergency situations (Fight or flight)
Parasympathetic autonomic motor neurons?
are responsible for everyday function (rest and digest)
Association neurons are also called?
Interneurons
Where are association neurons located?
in the CNS
Structural classification of neurons is based off?
of processes that extend from the cell body
Pseudounipolar neurons are?
Sensory and have 1 process that splits like a T to form 2 long processes
Bipolar neurons are?
Retina of the eye, choclea of ear
2 processes at each end
Multipolar neurons are?
The most common and have several dendrites, 1 axon
motor neurons and interneurons
Nerves are?
Nerves=bundles of axons located in PNS
and most will have both sensory and motor neurons
Mixed nerves are?
sensory and motor neurons
Tracks are?
bundles of axons located in CNS
Neurons come from?
ectoderm
Most of the connective tissue is derived from?
mesoderm
Neuroglial cells come from?
ectoderm
What type of nerve cells DO NOT conduct electrical impulses?
Neuroglial cells
What cells form myelin sheaths around PNS axons?
Schwann Cells
What do satellite cells do?
Support cell bodies with ganglia in PNS
What type of cells form myelin sheaths around CNS axons?
oligodendrites
What do Microglia do in the CNS?
phagocitize foreign and degenerated material.
However they produce free-radicals that can result in neurogenerative disorders
What do astrocytes do in the CNS?
Regulate the external enviroment of neurons and induce formation of the blood brain barrier
What do epindiaml cells do>
secrete cerebrospinal fliud that line brain ventricles and central canal of spinal chord
Schwann cells are also called?
neurilemma
Small axons in the PNS will be __________.
unmyelinated
Myelinated axons transport
impulses more rapidly
Myelin sheath in the CNS is formed by
oligodendrites
Myelin gives axons?
white color
White color given by myelin is called?
White matter
Unmyelinated axons are called?
grey matter
If schwann cell is only wrapped around axon once, it is called?
neurilemma
If a schwann cells is wrapped more than once around axon, it is called?
a myeline sheath
If an axon in the PNS is cut, the severed part?
degenerated and is phagocitized by schwann cells
What happens when schwann cells phagocitize severed axons in PNS?
The schwann cell forms regeneration tube releasing growth factors which release axon spouts in tube
How long does it take to regrow a new PNS axon?
~200 days
CNS axons that are cut?
do not regenerate
What occurs if a CNS axon is severed?
Death receptors form and promote apoptosis of oligodendrites
NoGo proteins are?
inhibitory proteins that are produced by oligodendrites that prevent regeneration
Astrocytes do what after a CNS axon is severed?
form ‘glial scars’ as a physical block
Research into the inhibition of No-go showed?
improved axonal regeneration
Neurotropins are?
autocrine regulators secreted by neurons and neuroglial cells that promote axonal growth
What does nerve growth factor do?
Promotes the survival and growth of sympathetic and sensory neurons in developing fetal brain
responsible for maitence of sympathetic growth factor
aids in regeneration of sensory neurons after injury
Astroycutes make up?
90% of nervous tissue in the body
What type of nerve cell has feet-like protrusions that allow them to interact with alot of surrounding tissues?
Astrocytes
T/F Astrocytes do not produce action potential
True
What excites astrocytes?
They are excited by changes intracellular Ca2+ concentrations
When Ca2+ concentrations are high Astrocytes release____________ and end feet are on blood capillary. What does this stimulate?
prostoglandin and this stimulated vasodilation
What are the 9 functions of Astrocytes?
- take up extracellular K+
- Take up excess neurotransmitters from synapse
- Take up glucose from blood
- Store Glycogen
- Necessary for synapse formation, maturation and maitence
- regulate the growth of nervous tissue in brain
- Secrete glial- derived neurotrophic factor
- induce formation of blood/brain
- Release gliotransmitters
Astrocytes take up glucose from blood by?
Metabolizing it into lactate or lactic acid to provide energy for neurons
What are the gliotransmitters?
Glutamate, ATP, Adenosine, and D-serine
What does an MRI visualize?
Visualizes the metabolic actives of the brain
Functioning __________ are just as important as functioning ________.
astrocytes/neurons
What is the blood-brain barrier?
Structures and cells that selectively prevent things from entering CNS
T/F There are no pores in capillaries of the brain between adjacent cells
True
The adjacent cells in CNS are held together by?
zona occulens
T/F THere is no paracellular transport in the brain, just transcellular movement
True
What cells are responsible for the proteins of the tight junctions, production of ion channels and carrier proteins, and production of enzymes to destroy poteintially toxic materal
astrocytes
T/F Most drugs cannot cross the blood/brain barrier
true
What is L-Dopa?
The pre-cursor to dopamine
What regulatory molecule is associated with parkinsons?
dopamine
What is one of the issues with treating menegitis?
Antibiotics have issues crossing the blood-brain barrier
Poteintial difference is?
the voltage across the membrane
Resting membrane poteintal is when?
a cell is not conducting an impulse
The resting membrane potential of a cell is?
-70mv
What contributes to the resting membrane potential of a cell?
Large organic ions inside cell
Na+/K+ pump
Permeability to inorganic cations
What is an electrochemical gradient?
Combo of concentration gradient of ion and its attraction to opposite charges
How do you measure changes in potential difference?
2 electrodes, one in cytoplasm and 1 in ectracellular fluid
An oscilloscope allows?
one ot visualize changes
What is causing membrane potential?
Ion gating-changes in the flow of ions through channels
Why is the cell most permeable to K+?
K+ has more channels than other ions
K+ has two types of channels
What are the two types of channels that K+ has?
No gate at all=leaky channels
Voltage gated channels
T/F Na+ has no leaky channels only voltage gated
True
depolarization occurs to
-55mv
When D.P is -55, what occurs
at -55mv this is a que for Na+ voltage gated channels to open, and once open Na+ rushes inside cell
When Na+ is rushing into the cell, it’s voltage gated channels remain open to what mv before closing?
-30mv
At -30mv, what occurs?
K+ voltage gates channels open and K+ leaves cell
The action of K+ ions leaving the cell causes?
repolarization
Action potentials overshoot to?
-85mv
Anytime you get -55mv you will?
get an action potential
T/F The size of a stimulus will not affect the size of an action potential.
True
How does the size of a stimulus affect nervous tissue?
The larger the size the more neurons will activate
What is the process of the size of an stimulus affecting more neurons called?
recruitment
What is the refractory period?
A new action potential can’t start until the previous one is finished
The absolute refractory period is?
When a new stimulus has no effect
The relative refractory period is when?
A supermaximal stimulus can start a new action potential
What are cable properties?
Ability of neurons to conduct charges through the cytoplasm
Cable properties are?
fairly poor
Where are voltage gated channels concentrated at?
The nodes of Ranvier
On unmyelinated axons, how is the conduction rate?
slow
What is a salatory conduction?
The concentration of voltage gated channels on the nodes of Ranvier because conduction rate being quicker
A higher diameter of axon has a higher?
conduction rate
What is the functional connection between a neuron and a 2nd cell?
the synapse
The synapse of the CNS is?
neuron to neuron
The synapse of the PNS is?
Neuron to neuron or neuron to effector cell
Neuro to muscle is called?
neuromuscular junction
A pre-synaptic neuron is?
a neuron before the synapse
A post-synaptic neuron is?
neuron after synapse
Axodentritic means?
axons to dendrites
Axosomatic means?
axon to cell body
Axoaxonic means?
Axon to axon
Exectrical synapses occur?
via gap junctions
For electrical synapses to occur the cells must be?
less than 2nm apart
6 proteins called ______ form transmembrane structures with an aqueous core due to phosphorylation or de-phosphoralation
connexins
Exectrical synapses occur in what type of tissue?
smooth muscle, cardiac muscle, some neurons, some neurons of brain and between neurolgial cells
Chemical synapses are?
junctions between neuron and 2nd cell
An enlargement on the tips of axons of pres. neuron are called?
terminal buttons
Within terminal buttons are?
synaptic vesicles containing neurotransmitters
What are SNARE proteins?
dock synaptic vesicles to cell membranes
Botulism causes?
paralysis because of a toxin from bacteria that alters snare fusion complexes so they cannot undergo exocytosis and can cause death due to diaphram not being able to contract
The synaptic cleft?
space between pres and post cells
10nm across
What stablizes the synaptic cleft?
cell adhesion molecules (CAMs) hold the two cells together
Action potentials travel down the terminal buttons causing?
release of Neurotransmitters
More action potentials cause more?
release of neurotransmitters
