Reading...
Play button
Play button
Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
87 Cards in this Set
- Front
- Back
|
Electrical gradient
|
*the separation of anions and cations
**electrical pull when one side is greater than the other |
|
|
Electrochemical gradiant
|
*Na+ ions have a gradient that moves into cell due to being attracted
|
|
|
Voltage
|
*measures magnitude of charge
|
|
|
Current
|
*the flow of charge (inc. in drive = inc. of voltage)
|
|
|
Resistance
|
*something that gives hinderance to flow of electrons
|
|
|
Conductor
|
*has low resistance where charges can flow easily
Ex) H2O |
|
|
Insulator
|
*plasma membrane, mylene sheath
Ex) rubber layer on wire |
|
|
The membrane Potential
|
*the difference in charge across membrane (separation of charge)
|
|
|
What is the relative permeability of Na+?
|
*1 (it is only slightly permeable)
|
|
|
Is Na+ relatively high in ECF or ICF?
|
* high in ECF and low in ICF
|
|
|
What is the relative permeability of K+?
|
*40-75 times more permeable than Na+
|
|
|
Is K+high in ECF or ICF?
|
*high in ICF low in ECF
|
|
|
What is the relative permeability of CL-?
|
*freely permeable
(no active transport, but the pull of the electrons allow it it flow) |
|
|
Is CL- higher in ECF or ICF?
|
*higher in ECF and lower in ICF
|
|
|
What is the relative permeability of A-?
|
*zero permeability
|
|
|
Is A- high in ECF or ICF?
|
*high in ICF and low in ECF
|
|
|
Is there more anions/cations inside or outside the cell?
|
*more cations outside the cell, and more anions inside the cell
|
|
|
How is the membrane potential measured?
|
*measured in millivolts (1V=1000mV)
|
|
|
In the membrane potential, what % is made up of K+ and what % is made up of the NA+/K+ pump?
|
* 80% is made up of K+ and 20% is made up of the NA+/K+ pump
|
|
|
If only 1 ion could diffuse, what would be the equilibrium potential of K+?
|
*Ek+= -90 mV
|
|
|
If only 1 ion could diffuse, what would be the equilibrium potential of NA+?
|
ENa+= +60 mV
|
|
|
Resting membrane Potential
|
*for most cells it is -65 to -85mV
*it depends on the concentration of ion inside & out and permeability of each ion *It is affected most by K+ because it is most permeable and secondly the NA+/K+ pump |
|
|
Polarization
|
*polarization happens at -70 mV
|
|
|
Depolarization
|
*loss of polarity (going closer to zero)
|
|
|
Repolarization
|
*gaining back polarization by going closer to -70
|
|
|
Hyperpolarization
|
*going below -70 or going back up to -70
|
|
|
What are the different parts of the neuron?
|
*Cell body/Soma
*Dendrites *Axon *Axon terminals *Axon hillock *Telodendria *Node of Ranvier |
|
|
Cell body/Soma
|
*the main part of the nearon
|
|
|
Dendrites
|
*takes the electrical signals toward the cell body
|
|
|
Axon
|
*takes the electrical signals away from the body
|
|
|
Axon hillock
|
*where the axon starts
|
|
|
Node of Ranvier
|
part of the neuron that is unmylenated.
|
|
|
How many neurons can a typical cell have?
|
1,000 to 10,000 synaptic neurons
|
|
|
Pseudounipolar neuron
|
*one extension on the neuron
EX) when you wiggle your toe |
|
|
Bipolar neuron
|
*two extensions on the neuron
EX) retina neurons for vision and neurons for smell |
|
|
Multipolar neurons
|
*many extensions on the neuron
EX) most neurons on the body have this (CNS) |
|
|
Afferent neurons
|
*Sensory and Input
|
|
|
Efferent neurons
|
*motor and output
|
|
|
Interneurons
|
*connecting association
*located entirely inside CNS (not found in PNS (also called connecting/association neurons) |
|
|
The neuron lifespan is usually...
|
*long lifespan( usually dies with old age)
*can go through mitosis |
|
|
What can stimulate neurons?
|
Working out stimulates neurons
|
|
|
There are two ways you can increase conduction.
|
*size of the axon (an adaptation if you do not have a myelinated sheath
*myelinated axon |
|
|
50% of the neuron volume of the brain is made up of what type cell?
|
Astrocytes
|
|
|
What system can you find sensory neurons?
|
the PNS and sends signals from the receptors to the CNS
|
|
|
What system can you find somatic motor neurons?
|
CNS and sends signals to PNS
|
|
|
What system can you find the automatic motor neurons?
|
CNS and sends signals to PNS
|
|
|
What system can you finds autonomic ganglion
|
CNS and sends signals to PNS
|
|
|
Astrocyte
|
*covers blood capillaries of the CNS
*most common glial cell *involved in blood barrier, buffering K+ levels, recycling neurotransmitters, regulation of adult neurogenesis *directs neurons during fetal development of brain |
|
|
What is neurogenesis?
|
*the production of new neurons
|
|
|
Schwann cells
|
*located in the PNS
*surrounds axons of all peripheral nerve fibers, forming a neurilemmal sheaths, or sheath of Schwann; wrap around many peripheral fibers to form myelin sheaths, also called neurolemmocytes * |
|
|
Oligodendrocytes
|
*located in the CNS
*forms myelin sheaths around central axons, producing "white matter" of the CNS |
|
|
Microglia
|
*locates in the CNS
*Phagocytose pathogens and cellular debris in the CNS |
|
|
Ependymal Cells
|
*Located in the CNS
* forms the epithelial lining of the brain cavities (ventricles) and the central canal of the spinal cord; cover turfs of capillaries to form choroid plexuses- structured that produce cerebrospinal fluid |
|
|
What is the speed for a neuron with myelin sheaths?
|
* 3m-130m per second
|
|
|
What is the speed for a non-myelinated neuron?
|
* 1m-or less
(myeline sheaths seem to increase the velocity and decrease the energy cost) |
|
|
what do myeline sheaths do for neurons?
|
*myeline sheaths seem to increase the velocity and decrease the energy cost
|
|
|
Why is regeneration or recovery high in PNS but lower in CNS?
|
*because schwann cells are only in the PNS and they help assist recovery
|
|
|
Which cells in the CNS produce proteins that inhibit growth?
|
*oligodendrrocytes
|
|
|
How many axons can myelin sheaths make?
|
60 axons
|
|
|
*greater the stimulus =
|
*greater the action potential
|
|
|
Which ion brings about depolarization (influx)?
|
*Na+ brings about depolarization (excitatory signals)
|
|
|
Why are excitatory signals needed?
|
*they are needed to create action potentials
|
|
|
What is the thresh hold to generate action potential?
|
* -55
|
|
|
What thresh hold does the action potential go to when it efluxes?
|
* +30
|
|
|
Which ion brings about repolarization (eflux out of the cell )?
|
*K+
|
|
|
What are the two types of electrical signals?
|
Graded potentials
Action potentials |
|
|
Graded potentials
|
*depolarization is needed for it to happen
*only travel on axons and axon hilic *Hyperpolarizations occur *Its decremental *short signals *no refractory period *duration is only for a few msec to seconds *limited to cell bodies and dendrites *chemical gated channels or mechanically gated channels *amplitude changes (excititory and inhibitory) |
|
|
Action Potentials
|
*signals travel fast
*longer signals *non-decremental *remains the same in amplitude *you don't get action potential *only travels on axon *travel at different rates *all or none *you need multiple action potentials per second in order to contract something |
|
|
membrane potential is measured in what?
|
millivolts
|
|
|
Absolute refractory period
|
*due to inactive NA+ channels
*starts on the threshold of action potential and all the way to the resting pot. *during AB.Re>P membrane CANNOT generate another action Pot. (no matter hoe strong the stimulus is) |
|
|
Relative refractory period
|
*due to continued outward diffusion of K+
*sometimes can have another action potential BUT needs to be a higher or stronger stimulus |
|
|
Action potential events
|
*Depolarization
*Threshold potential *Voltage gated Na+ channels open *Closure of Na+ channels *Opening of K+ channels *repolarization *After hyperpolarization *Absolute refractory period *Relative refractory period *Duration: 1-2 msec (afer hyperpolarixation may last 15 msec) |
|
|
Action Potentials Conduction is in two ways
|
1) Propaganda (local current flow); slower and less efficient without myelin sheath
2) Saltatory; energy efficient with myelin sheath |
|
|
Stimulus intensity
|
1) frequency code= start sending action pot. at a higher rate
2)population code= more neurons start to transmit signals Ex) dim from bright, weak from strong |
|
|
Stimulus interpretation
|
*primarily based on where the info is being analyzed
Ex) taste, smell |
|
|
Organization of Nervous System
|
*the CNS has the brain and the spinal cord= input(afferent signals) comes to the CNS and output (efferent signals) comes out of the CNS
*Afferent signals and efferent signals are connected to the PNS *sensory stimuli (consciousness) and viseral (unconciousness) goes to the afferent signals *Efferent signals are comprised of Somatic and automatic nervous systems *somatic is voluntary (to skeletal muscles) and automatic is non-voluntary (smooth and cardiac muscle) *somatic goes to muscle neurons w *automatic branches into sympathetic N.S (fight or flight) and nonsympathetic N.S (digestion and relaxation) |
|
|
Tract
|
grouping of axons that interconnect regions of the CNS
|
|
|
Nucleus
|
grouping of neuron cell bodies within the CNS
|
|
|
Ganglion
|
grouping of neuron cell bodies located outside the CNS
|
|
|
Automatic motor nerve
|
nerve that stimulates contraction (or inhibits contraction) of smooth and cardiac muscle and that stimulates glandular secretion
|
|
|
Somatic motor nerve
|
nerve that stimulates muscle contraction of skeletal muscles
|
|
|
Nerve
|
Cablelike collection of many axons in the PNS; may be mixed (contain both sensory and motor fibers)
|
|
|
Motor neuron (efferent neuron)
|
neuron that transmits impulses from the CNS to an effector organ
Ex) muscle |
|
|
Sensory neuron (afferent neuron)
|
neuron that transmits impulses from a sensory receptor to the CNS
|
|
|
Association neuron (interneuron)
|
Multipolar neuron located entirely within the CNS
|
|
|
Peripheral Nervous System (PNS)
|
Nerves,ganglia, and nerve perplexes (outside the CNS)
|
|
|
Central nervous system (CNS)
|
brain and spinal cord
|
