A Phys - Quiz 6 info (p. 88-124) Flashcards
What are the differences between invertebrate and vertebrate light reception
- invertebrates have PLC made as teh 2nds messenger from the G-protein (transducin) and that is used to stimulate PIP2 in the membrane which in turn makes IP3 and DAG. These two messengers close the Na+ channel and stop Na+ influx.
PIP2 stands for;
Phosphatidyl 4, 5-bisphosphate
DAG stands for;
Diacylglycerol
IP3 stands for;
Inositol triphosphate
PLC stands for;
Phospholipase C
PDE stands for;
phosphodiesterase
When the invertebrate photoreceptor cell is exposed to light, what happens?
- the cell depolarizes, moving away from the K+ Nernst pot.
- there is increase G(Na) (maximum sodium conductance)
- it is moving towards 0/towards E(Na)
- when light is no longer on, the cell hyperpolarizes (Na+/K+ ATPase) and returns to a negative, resting potential.
When the vertebrate photoreceptor cell is exposed to light, what happens?
- the cell is close to zero and hyperpolarizes towards the K nernst potential
- there is a decrease in G(Na) (maximum sodium conductance
- once the light is off, the potential depolarizes as Na+ influxes.
What is the ERG? What is it used for?
It is an electroretinogram that tracks the electrical activity of the retina in response to light stimulus
What is the a wave in an electroretinogram?
it is hyperpolarization due to inhibition of dark current in photoreceptor cells, it is the first movement and it is downward on a graph; it happens immediately after light is applied.
What is the b wave in an electroretinogram?
it is the depolarization of bipolar cells, it is second wave and is significantly larger than the a wave; it happens directly after the a wave and happens while light is applied.
What is the c wave in an electroretinogram?
it is the interaction between photoreceptor cells and pigmented epithelium; this happens after the light is turned off and it is a signal that these cells are functional (bc they are wrapped around photoreceptor cells)
Across a turtle, toad, rabbit and human, how are the ERGs similar and different?
Similar:
- they all have an a and b wave
- the a and b wave are in the same directions as human waves
Different:
- the toad and turtle have a d wave as well
- there is variability in the amount of volts and milliseconds for each
What is nociception?
the detection of painful/noxious stimuli
Mechanical nociceptors are most _____, and respond to __________ damage such as: _______, crushing, and _______. These are also the _____ to respond
basic; mechanical; cutting; pinching; fastest
Thermal nociceptors respond to _________ extremes, they are enabled by _______ _____ channels that open at certain _______
temperature; TRP cation; temperatures
Polymodal nociceptors are most _____ and respond ______ to all kinds of damaging stimuli; they respond to _____ released from ______ tissues. It takes _____ to work but senses pain over a ______ ______.
complex; equally; chemicals; injured; longer; long period
_____ _____ activates nociceptors
tissue damage
What do damaged cells release?
signaling chemicals, 5-HT, bradykinin, prostaglandins
What do chemicals like 5-HT, bradykinin and prostaglandins open?
cation channels on nociceptor cells and trigger APs down the dorsal root ganglion neuron
How do nociceptors send signals to the brain?
they synapse in the spinal cord with afferent neurons to the brain
What are some characteristics of pain?
- initial sharp twinge of pain via the fast pain pathway
- secondary, diffuse wave of pain shortly after + occurs via the slow pain pathway
What is involved in the fast pain pathway (+ characterize it)
characterization: initial sharpe twinge of pain
Involved:
- mechanical nociceptors
- thermal nociceptors
What is involved in the slow pain pathway (+ characterize it)
characterization: secondary, diffuse wave of pain shortly after painful stimuli
involved:
- triggered by chemicals released by damaged tissue + detected by polymodal nociceptors
- prolonged pain
What is true about the nervous system across organisms?
different organisms have different structures and complexities of a nervous system, the human has a very complex nervous system while the sea star contains a neural ring and some radial nerves.
What are neural nets?
a connected series of neurons who do a specific function
What are ganglia?
a collection of nerves with an entrance and exit point for integration
What happens to the amount of branches closer to the brain?
There are more branches closer to the brain and less branches further from the brain.
What are some functions of the CNS that all mammals and vertebrates can do
1) Subconsciously regulate
2) Voluntarily control movement
3) Conscious awareness of body and surroundings
What are some other functions of the CNS that only mammals can do
4) Experience emotions
5) Engage in higher cognitive processes (thought/memory)
Monosynaptic reflex arc/loop information flow in the NS
the stimulus on tissue and travels along the axon (via neuron with cell body on outside of cell) until it reaches a synapse (central nervous system) and the NTs evoke some type of response in the postsynaptic cell. There can be a motor neuron that then releases NTs into an effector cell
common in humans
Single-cell connection of information flow in the nervous system
the stimulus hits the tissue, and dendrites are embedded into the tissue. The dendrites are connected to the soma/receptor cell and the AP is fired, it travels along the axon until the axon terminals which are attached to the effector cell
Polysynaptic reflex arc information flow in the NS
The stimulus causes dendrites in receptor cell to influence an afferent sensory neuron through APs and NTs. This then synapses on an interneuron and that synapses to an efferent motor neuron (these two neurons are part of the central nervous system), the efferent motor neuron produces some change in the effector cell.
What are the three main functional classes of neurons?
Afferent, efferent and interneurons
Afferent neurons can _____ the _______ environment and send signals to __ __ __
+ some examples are:
sense; peripheral; CNS
- inner hair cells, gustatory cells, nociceptors
Efferent neurons can _____ CNS information/commands to _____ organs
+ one example is:
transmit; effector
- motor neurons
Interneurons can _______ ______ information, coordinate ______ response, and modify both types of information content. This is only in __ __ __ and most abundant neuron type: ______ _____ neurons
integrate afferent; efferent; CNS; higher-order neurons
Interneurons are cool because:
- they have more complex/finer control and the integrator is modifying affarent information -> shows complexity of NS
A unipolar (sensory) neuron is characterized by:
- the dendrites are getting information from one area/they are embedded into one area and the dendrites are not on the cell body (cell body off to side of axon)
A multipolar (inter- and motor) neuron is characterized by:
dendrites are getting information from many different sources because they are pointing in many different directions. The dendrites are connected to the cell body and from the cell body, an AP travels down axon
What can we see between the NS’s of an amphibian and mammal?
- the functional NS is preserved
What is the lateral line?
a system of sensory organs used to sense movement, vibration and pressure in the water surrounding the aquatic animal. (fish, sharks, mantas, etc.)
What is a dermatome?
one set of spinal nerves that control one block of muscle