Physio Lab exam 2 Flashcards
What factors affect RMP?
Sodium/Potassium pump (3 Na+ out, 2 K+ in), K+ leak channels
What factors affect release of NT?
Presynaptic membrane undergoes exocytosis
How does Lidocaine work?
Blocks the conduction of action potentials by binding and blocking the voltage gated Na+ channels to prevent action potentials.
Why didn’t curare block the AP?
it is an alpha-toxin that binds to acetylcholine binding sites on the postsynaptic cell membrane, which prevents the acetylcholine from acting. Curare blocks synaptic transmission by preventing neural impulses to flow from neuron to neuron. It does allow the action potential to travel in the axon, it just doesn’t pass it on to the dendrite.
Curare competes with ACh for attachment to the nicotinic ACh receptors
What factors affect action potential velocity?
Myelin sheath, temperature, axon diameter
When does spatial summation occur?
As a result of the convergence of presynaptic axon terminals on the dendrites and cell body of a postsynaptic neuron
What is an EEG?
The recording of electrical activity on the scalp.
How is EEG administered?
By placing electrodes on the scalp
EEG’s are used to diagnose…
epilepsy, other abnormal states
the absence of an EEG can be used to signify brain death
Alpha waves are best recorded from ____ and _____ regions while a person is _____ and relaxed.
parietal, occipital, awake
Beta waves are strongest from the _____ lobes, especially near the ______ gyrus
frontal, precentral.
How are beta waves produced?
By visual stimuli and mental activity
Theta waves are emitted from the ____ and _____ lobes and are common in _____ and _________.
temporal, occipital. Common in newbord infants/adults. Recording of theta waves in awake adults indicates severe emotional stress.
Delta waves are emitted in a ______ pattern from the ________
general, cerebral cortex. Delta waves are common during sleep and in an awake infant. Presence of delta waves in an awake adult indicates brain damage.
Chemoreceptors respond to
chemical stimuli
taste buds, olfactory epithelium
Photoreceptors…
transduce light
rods and cones in retina or eye
Thermoreceptors…
respond to temperature changes
Mechanoreceptors…
respond to deformation of cell membrane
touch/pressure receptors in skin and hair cells within ear.
Nocioceptors…
respond to intense stimuli by signaling pain
Proprioceptors…
signal positional info of body parts.
Cutaneous receptors include
touch & pressure receptors, heat/cold receptors, pain receptors.
Function of receptor
they transduce (change) different forms of energy into the energy of nerve impulses that are conducted into the CNS by sensory neurons.
Different forms of modalities include
sound, light, pressure,
Define two point threshold
Minimum distance at which two points of touch can be perceived as separate. Measure of the distance between receptive fields.
2 point threshold is indication
of tactile acuity, or sharpness of touch perception
What are phasic receptors?
receptors that respond with a burst of activity when a stimulus is first applied, but then quickly decrease their firing rate-adapt to the stimulus- if the stimulus is maintained.
Pacinian corpuscle (pressure receptor)
Define refraction
“bent” Light that passes from a medium of one density into a medium of a different density is refracted.
define visual acuity
sharpness of vision
Define myopia
Nearsightedness, image will focus in front of retina. Eyeball is too long. Corrected with glasses with concave lenses.
Define hyperopia
far sightedness, eyeball is too short. Rays focus behind retina. Convex lens correct farsightedness
Define astigmatism
Asymmetry of cornea, lens. Would not be able to look at a circle of stripes, part of stripes would blur. Corrected with cylindrical lenses.
Define accomodation
The ability of the eye to keep the image focused on the retina as the distance between the eyes and object varies
Define Nystagmus
Eyes involuntarily move left and right after spinning,
What causes blind spot?
It is the result of the optic nerve connecting with the back of your eyeball. There are no light sensitive rods or cones here
What is afterimage?
It is an optical illusion where the image still apears after seeing the picture
Cones include
blue cones (s cones), red cones (L cones), green cones (M cones)
What is sensorineural deafness?
transmission of nerve impulses anywhere from the cochlea to the auditory cortex is impaired
What is conduction deafness?
transmission of sound waves through the outer and middle ear to the oval window is impaired
what is isotonic contraction?
muscle is in constant tone, pulling same force, lifting something for example
what is isometric contraction?
when muscle stays the same length even if force of contraction increases. for example, standing still
what is eccentric contraction?
muscle acts like a brake. Muscle contracts but still extended. pushup!
List what cells light passes through retina.
Fiber optic cells, Ganglion cells Amarine cells Bipolar cells Horizontal cells Photoreceptors (rods/cones)
