Midterm 2 chapters 6-8 Flashcards
Light can be thought of as …
- Particles of energy (photons)
- waves of electromagnetic radiation
What is the smallest possible unit of light energy?
A photon
What is an Electromagnetic Spectrum?
a continuum of energy produced by electric charges is radiated as waves
How do Colours work?
certain objects reflect specific wavelengths of light and these wavelengths create a pattern of firing photorecepetors
Where is light projected onto in the eye?
light is projected onto the retina
what part of the retina represents the object we are looking at?
The fovea
What focuses the image onto the retina?
The cornea
What part of the eye is fixed?
the lenses
What kind of photoreceptors line the retina?
Rods and Cones
What part of the eye is rich in cone receptors?
the fovea
What is the fovea specialized for?
it is specialized for seeing fine metals and colours
What do photoreceptors do?
they convert light into nerve impulses aka transduction
What is Transduction?
- when we take some outer stimulus (light or sound etc) and translate it into something the brain can understand which is an action potential
- the process of turning light into electricity
What is an Opsin?
long protein strand
What is Retinal?
a light sensitive molecule
What helps improve eyesight?
Vitamine A and Retinal
What are visual receptors?what happens at the visual receptors?
- outer segment
- where light acts to create electricity
- transduction occurs when retinal absorbs light
When does Isomerization occur?
occurs when retinal changes shape, sticking out from opsin
What is Visual Pigment Bleaching?
- when retinal separates from the opsin
- the retina then becomes lighter in colour
What is Visual Pigment Regeneration?
- as light remains on, more and more of the retinal is detached, but more and more are regenerated
- opsin and retinal are rejoined
What is the biggest difference between Rods and Cones?
Cones are Photopic (daytime vision)
rods are Scotopic (nighttime vision)
Describe Cones
- found mostly in the fovea
- high-acuity (sharpness)
- colour vision
- needs a lot of light
Describe Rods
- found mostly in periphery
- low-acuity (blurry)
- gray scale vision
- needs little light
- more convergence
What is Convergence?
when we have more than one neuron all converging their inputs into one neuron
What is Selective Reflection?
some wavelength are reflected more than others
What is Transmission?
only some wavelengths pass through the object or substance
What are the two main theories that attempt to explain how we perceive colours?
- trichromatic theory: colour vision depends on activity of three different colour receptor types (red, green, blue)
- Opponent process theory: colour vision is related to opposing responses by blue-yellow and red green
What is Protanopia?
a colour deficiency where your missing the long wavelength (red) pigment
What is Deuteranopia?
a colour deficiency where your missing the wave medium length (green) pigment
What is Tritanopia?
possible missing the short wavelength pigment ?
extremely rare
What is a soundwave?
the alternating increases and decreases in pressures creating soundwaves
What are the components of the Auditory Signal?
Frequency (pitch), Amplitude (volume), Complexity (timber)
What is Frequency?
the rate at which waves vibrate
What is Amplitude?
the intensity of the sound
What is Complexity?
most sounds are a mixture of frequencies
What amount of Hz are humans most sensitive to?
2,000 -4,000 Hz which is frequenct range for most speech sounds
what does the ear canal do?
helps amplify the sounds
what does the eardrum do?
pass vibration to the malleus, incus, stapes
What is the Vestibular System?
- it is needed for balance
- there is a canal for each plane we can be in
- tells your head where it is relative the the ground
Where is the Organ of Corti located?
the cochlea
What do the cilia do?
produce electrical signals
What kind of frequency sounds does the bases of basilar membrane code?
High frequency sounds
What are the two Primary Biaural Cues?
Interaural Time Difference (ITD)
Interaural Level Difference (ILD)
what is Interaural Time Difference?
based on the fact that there can be differences in the time it takes sound to arrive at one ear compared to the other
What is Interaural Level Difference?
localization for high frequency is accomplished using intensity difference
True or False: Cochlear nuclei are ipsilateral.
True
True or False: Damage to the ear itself, or auditory canal, or middle ear, or cochlear nucleus will lead to complete deafness in both ears
False: in one ear
What are the Main components of the Somatosensory System?
Nocioception
Hapsis
propioception
balance
What is Nocioception?
the perception of pain and temperature
What is Hapsis?
perception of objects using touch and pressure
What is Propiocpetion?
knowledge of the position of your limbs in space
What is balance?
controlled by the vestibular system in the inner ear
What does the superior colliculus receive information from?
The superior colliculus receives information from the retina
What does the inferior colliculus receive information from?
the inferior is receiving information from the superior olivary nuclei
What part of the thalamus receives auditory information?
The Medial Geniculate Nucleus (MGN)
What are neurons in the auditory cortex tuned based on?
they are tuned based on input and experience
Describe Rapidly adapting receptors
they respond quickly to sudden changes but adapt quickly
Describe slowly adapting receptors
a stronger stimulus takes longer to adapt
example: if you push down hard on your arm it will take a long time to adapt
What do sensory receptors respond to?
they respond to pressure, stretch, or vibration
Are Merkel receptors slow adapting or fast adapting?
merkel receptors slow adapting
Are Meissner Corpuscle fast adapting or slow adapting?
Meissner Corpuscle are fast adapting
What are the two main sensory Pathways?
Medial Lemniscus System and spinothalamic
What is medial lemniscus system?
large fibers, used for fine touch, proprioception
What is spinothalamic?
smaller fibers, used for pain a temperature
What are the 4 Homunculi?
fast adapting, slow adapting, proprioception, temp and pain
What are tactile Receptive fields?
neurons in the ventral posterior nucleus
What are receptive fields?
the location on the skin that, when stimulated, causes the receptor to fire
What is the Direct pathway model and what is a con of this theory?
researchers assumed that pain responses were created in receptors in the skin and sent directly to the brain
Problem: pain can occur when there is no stimulation on the skin ex phantom limb
What is the Gate control Model?
- pain signals enter the spinal cord are sent to S1
- additional pathways can act as a “gate” to increase or decrease pain signals leaving the spinal cord
What do S-Fibers do?
carry pain signals from nocioceptors
What do L-fibers do?
carry information about tactile stimulation (no pain)
What do T-Cells do?
Transmit pain signals to the brain
they determine amount of pain experienced: more activity, more pain
Whats is central control?
signals coming from the brain to help reduce pain sensation
What neurotransmitter activates the same receptor as opiates? and how does it work?
Endorphins, they both block incoming pain signals
What does Macrosmatic mean? What are some examples?
species that have a very keen sense of smell for survival
Ex dogs, cats
What does Microsmatic Mean? and give an example.
Species who depend less on their sense of smell for survival
ex humans
What is detection threshold?
the lowest concentration at which an odour can be detected
What is recognition threshold?
odor has to be increased by a fact of 3 for quality to become apparent
Where do smell receptors reside in?
the Olfactory Mucosa
True or false: there are new olfactory receptors created every few weeks to replace the receptors that have deteriorated
True.
Whats are the 5 main qualities of taste?
Bitterness, sourness, sweetness, saltiness, umami (savoury)
What are taste buds?
receptors in tongue and oral cavity in clusters of about 50
What is Filiform?
shaped like cones and are found over entire surface giving it its rough appearance, they do not contain taste buds
True or False: action potentials from taste cells are transmitted via sensory nerves
False: action potentials from taste cells are transmitted via cranial nerves
What is Ageusia?
the inability to recognize common tastes
What is the posterior parietal cortex good for?
the posterior parietal cortex is good for integrating sensory information, and send it to the frontal cortex
What is the order of operation for the Motor Cortical Network?
Posterior sensory cortex sends goals
then the prefrontal cortex plans movements
then the premotor cortex organizes movement sequences
then the motor cortex executes actions
What is the posterior parietal cortex used for?
the posterior parietal cortex is used for attention (helps direct/disengage attention)
What is Proprioception?
Monitors limbs
What is Optic Ataxia?
damage to the posterior parietal area, difficulty reaching toward and grasping objects
What is Limb Apraxia?
when you can’t perform purposeful movement in the absence of primary motor deficit
What does Ideomotor mean?
incorrect execution of the action
What does Ideational mean?
when you lose knowledge of the goal of the action
What is Pantomime?
asking the subject to generate a movement without an object present
What is Imitation?
asking the subject to imitate your movement
What is Ideomotor apraxia?
when people have deficits in their ability to plan or complete motor actions that rely on semantic memory . they can explain how to perform an action, but unable to “imagine” or act out a movement
What is Ideational/conceptual apraxia?
when people can’t conceptualize a task and struggle to complete multistep actions
What does somatotopic Mean?
more cortex devoted to body parts that make complex movements
What 3 nuclei is the Basal ganglia comprised of?
caudate, putamen, globus pallidus
what does the basal ganglia play a critical role in?
the basal ganglia plays a critical role in managing the force of movements and motor learning
What does the cerebellum play a critical role in?
maintaining balance and posture, helps coordinate and accurately time motor output
What happens when someone has a cerebellar lesion?
do not adjust movements as easily
What are the 4 descending motor pathways?
two dorsolateral
- corticospinal
- corticorubrospinal
two ventromedial
-corticospinal
cortico-brainstem-spinal tract
What is a Corticospinal dorsolateral tract?
What does it control?
descend through the medullary pyramids, then decussate
it controls the wrists, hands, fingers, toes
What is a corticorubrospinal dorsolateral tract?
what does it control?
synapse at red nucleaus and cross before the medulla
it controls some face muscles and distal muscles of arms and legs
What is a cotricospinal ventromedial tract?
descends ipsilaterally, axon branch and innervate interneuron circuits bilaterally in multiple spinal segments
what is cortico-brainstem-spinal ventrolmedial tract?
interacts with various brainstem structures and descends bilaterally carrying information from both hemispheres
What are the differences between dorsolateral and ventromedial?
dorsolateral terminates in one contralateral spinal segment, controls distal muscles, and controls limb movements
ventromedial is bilateral innervation, controls proximal muscles, posture and whole body movement
What are muscle spindles?
they are embedded in muscle tissue, they detect changes in the muscle length
What are golgi tendon organs?
embedded in tendons, detect muscle tension
