Section 2: The Sensory, Motor, and Memory Systems Flashcards
Review/Learn Section II of the Science Pentathlon 23-24 Study Guide.
What structure does the visual system begin with?
the eye
Where does the transduction of light take place?
the retina
What part of the eye is reshaped and shaved down during LASIK eye surgery?
the cornea
What is the cornea?
the front, transparent part of the eye where most fraction takes place
What is the iris?
the colored part of the eye
What does the iris do?
it controls the size of the pupil to allow the optimal amount of light through
The iris contracts and the pupil gets smaller in bright or dim light?
bright light
The iris relaxes and the pupil expands in bright or dim light?
dim light
Where does the cornea focus light on?
the retina
What part of the eye changes the focal length of light?
the lens
What is farsightedness?
when the muscles in the lens become stiff or when the distance between the cornea and retina is too short
What is myopia?
when the distance between the cornea and the retina is too long
Another word for myopia is ________.
nearsightedness
How can you fix myopia and farsightedness?
through LASIK eye surgery or glasses
How are the layers in the retina arranged?
inside out
What are photoreceptor neurons?
neurons that receive and transduce light
Why are the layers in the retina arranged inside out?
because the pigmented epithelium layer needs to be right outside of these cells
Where are the photoreceptor neurons in the eye located?
the retina
What do the pigmented epithelium cells do?
they absorb extra light and get rid of the old, worn-down parts of the photoreceptors that have to be constantly replaced.
Where is the choroid found?
right outside the pigmented epithelium layer
What does the choroid do?
it brings oxygen and nutrients to photoreceptors
Where is vision sharpest?
the fovea
Where is the fovea located?
the center of the retina
What are the 2 types of photoreceptors?
rods and cones
What type of light do rods process?
dim light
What type of light do cones process?
colors and bright light
What type of photoreceptor cells allow for full-color vision?
cones
What type of cone system do primates have?
a three-cone or trichromatic system
True or false: There are rods and cones in the fovea.
False, there are only cones in the fovea
What do rods have that they use to process and transduce light?
one opsin and one rhodopsin
How many types of cones do humans have?
3,
What type of wavelengths are seen as blue light?
short wavelengths
What type of wavelengths are seen as green light?
medium wavelengths
What type of wavelengths are seen as other warm colors of light?
long wavelengths
What allows primates to see hundreds of thousands of colors?
our trichromatic vision system
True or false: Animals can have different types of cones?
True, animals can have more or less cones and different types that have different absorption levels
What structure does the auditory system begin with?
the ear
What is sound?
a series of pressure changes in the air that has to be encoded by the brain to hear
What are the folds on our ears called?
pinnae
Another word for eardrum
tympanic membrane
What does the tympanic membrane do?
it transfers pressure waves into physical movement
What are the tiniest bones in the human body?
the ossicles
What are the 3 ossicles?
the malleus, incus, and stapes
Malleus comes from the Latin word for ________.
hammer
Incus comes from the Latin word for ________.
anvil
Stapes comes from the Latin word for ________.
stirrup
the cochlea does what
transduces sound
Cochlea comes from the Latin word for __________.
snail
What are semicircular canals for?
transducing the movement of the head and are crucial for balance
What 2 structures make up the semicircular canals?
utricle and saccule structures
The semicircular canals are a major part of which system?
the vestibular system
What does the vestibular system allow us to do?
it allows us to know where we are in space and how we’re moving through gravity
What sections make up the inner ear?
the cochlea and the semicircular canals
Most of the cochlea is covered in bone except for which area?
the oval window
Which ossicle pushes on the oval window?
stapes
What does the eustachian tube do?
connects the middle ear with the back of the throat
In severe cases of middle ear infection, what can happen to the auditory system?
the ossicles can stop fully, causing temporary hearing loss
How many fluid-filled cavities are in the cochlea, and what are they?
3, scala vestibuli, scala media, and scala tympani
What is the order of the 3 fluid-filled cavities in the cochlea (top to bottom)?
scala vestibuli, scala media, and scala tympani
What separates the cavities of the cochlea?
membranes
What membrane separates the scala tympani from the scala media?
the basilar membrane
Where is the organ of Corti?
on top of the basilar membrane
Where does auditory transduction take place?
the organ of Corti
What is auditory transduction?
the translation of the pressure wave to an electrochemical signal
What are chemoreceptors?
chemical receptors
What are the 5 tastes?
sweet, sour, salty, bitter, and umami
What does umami mean/describe?
deliciousness
Who identified umami?
Kikunae Ikeda
When was umami first identified?
1908
What food was first used to describe umami?
seaweed
Umami is our sensory experience of what chemical stimuli?
the amino acid L-glutamate
What is the organ of taste?
tastebuds
What are the bumps on our tongue?
papillae
Where are tastebuds found?
inside papillae
What is olfactory epithelium composed of?
olfactory receptor neurons and basal cells
Where is the olfactory epithelium layer found?
lining the top and back of the nasal cavity
How many olfactory receptors do humans have?
12 million
How many olfactory receptors do rabbits have?
100 million
How many olfactory receptors do bloodhounds have?
4 billion
How many olfactory receptors do most dogs have?
1 billion
What is population coding?
where broadly tuned neurons are used to encode and identify stimuli
What is the outermost layer of the skin?
the epidermis
What does the epidermis do?
protects against water and pathogens
What layer is found below the epidermis?
the dermis
What is found in the dermis?
blood vessels, sweat glands, hair follicles, and other important glands and structures
What is found below the dermis?
the subcutaneous layer
What is found in the subcutaneous layer?
blood vessels, connective tissue, and the axons of the sensory neurons
What types of information do the mechanoreceptors provide?
information about vibration, touch, and pressure
What are the 4 types of mechanoreceptors?
Meissner’s Corpuscles, Ruffini’s endings/corpuscles, Pacinian Corpuscles, Merkel’s Disks
What is the largest and most well-studied mechanoreceptor?
Pacinian Corpuscles
What type of stimuli are Pacinian Corpuscles good for?
deep vibration
Where are Meissner’s Corpuscles generally found?
in glabrous skin
What is glabrous skin?
hairless skin
Where is glabrous skin found?
your fingers, lips, the soles of your feet, and the palms of your hand
How do Meissner’s Corpuscles compare to Pacinian Corpuscles in size?
Pacinian Corpuscles are larger
Meissner’s Corpuscles transduce information about what?
low-frequency vibration and flutter
What kind of adapting quality do Meissner’s and Pacinian Corpuscles have?
a rapid-adapting quality
Do Ruffini’s and Merkel’s adapt as fast as Meissner’s and Pacinian?
no
What do Ruffini’s and Merkel’s do for the touch stimulus?
the fire action potentials for the duration of the touch stimulus
Where can Merkel’s and Ruffini’s be found?
Glabrous and non-glabrous skin
Where is touch acuity the highest?
fingertips and lips
Where are Merkel’s densely distributed?
fingertips and lips
In which layer(s) of skin are Pacinian Corpuscles found in?
the subcutaneous layer
In which layer(s) of skin are Meissner’s Corpuscles found in?
the dermis
In which layer(s) of skin are Ruffini’s Corpuscles found in?
the dermis
In which layer(s) of skin are Merkel’s disks found in?
the dermis and epidermis
In which layer(s) of skin are free nerve endings found in?
the dermis and epidermis
Mechanoreceptors near the surface of the skin are better for what type of information?
information that is precise about the location, size, and physical properties of the stimulus
Mechanoreceptors farther from the surface of the skin are better for what type of information?
information on the general qualities of the stimulus, like force and vibration
What is 2-point discrimination?
the measure of how close 2 nearby objects are when you can tell they are 2 different objects
What is 2-point threshold?
the smallest distance between 2 points where you can still tell there are 2 different stimuli
What can be used to measure 2-point threshold?
calipers or a bent paper clip
Where is 2-point discrimination highest?
fingertips, lips, and tongue
What do the areas with the highest 2-point discrimination have in common?
they all are highly innervated
How many spinal segments are there?
30
How many cervical spinal segments are there?
8
How many thoracic spinal segments are there?
12
How many lumbar spinal segments are there?
5
How many sacral spinal segments are there?
5
What is a dermatome?
all the skin innervated by one segment of the spinal cord
What is shingles?
a reactivation of the chickenpox virus that is dormant in one spinal nerve root, causing a rash to appear in that dermatome
Why is the map of dermatomes weirdly distorted and confusing?
because humans evolved from walking on all 4s with our heading pointing forward
Why is there no C1 dermatome?
because that dermatome is mostly motor output rather than sensory input
What is an example of a cranial nerve?
the trigeminal nerve
How do the head and neck send their sensory input?
through the cranial nerves
What are nerve endings that transduce temperature called?
thermoreceptors
When are low-threshold thermoreceptors activated?
temperatures between 15 and 45 C
When are high-threshold thermoreceptors activated?
temperatures below 15C and above 45C
Why are hot and cold sensations brought up to the brain through smaller axons than mechanoreceptors?
because temperature is not as crucial to reach the brain quickly compared to touch information
What is the cognitive experience of discomfort?
pain
What transduces pain?
free nerve endings
Where are free nerve endings located in the skin?
near the surface of the epidermis and also in the dermis
Pain at the tissue level is referred to as what?
nociception
What compound makes spicy peppers hot?
capsaicin
How does capsaicin make spicy food feel hot?
capsaicin opens the same calcium channels as warm thermoreceptors
What is hyperalgesia?
a temporarily increased sensitivity to pain
What is congenital analgesia?
a hereditary insensitivity to pain
When someone has defects in their free nerve endings, what other sensation can they not feel?
temperature
What are dorsal root ganglion or DRG?
bundles of cell bodies of sensory neurons
What are sensory neurons referred to as?
afferents
What are motor neurons referred to as?
efferents
What is proprioception?
your sense of where your body is in space
How does your body calculate proprioception?
by the amount of stretch and force on your muscles, limbs, joints, and tendons
What does decussate mean?
to cross the center of the body one time
Where does each pathway synapse, which will then relay that information to the cerebral cortex?
the thalamus
Medial Lemniscus comes from the Greek word for _________.
ribbon
How does touch and proprioception information travel to the brain?
through the dorsal column medial lemniscal system or DCML system
Where does the DCML wind up before traveling to the thalamus?
the brainstem
In the DCML, neurons carrying information synapse where in the brainstem?
the gracile nucleus of the medulla for information on the lower body, the cuneate nucleus of the medulla for the upper body
Where is all somatosensation processed?
the somatosensory cortex
How does pain and temperature information travel up to the brain?
the anterolateral spinothalamic system
What part of our body do lower motor neurons synapse onto?
our muscles
What chemical do they release in the space between the terminal and the muscle?
acetylcholine
What is the space between the terminal of the neuron and the muscle called?
the neuromuscular junction
Where do lower motor neurons get most of their information?
from upper motor neurons
What is the most famous example of a motor reflex?
the myotatic reflex
The primary motor cortex and other associated areas do what?
they plan voluntary movement, make decisions about movement strategies, and coordinate sequences of movement
What other area works with the primary motor cortex?
the premotor cortex
Where does most voluntary information travel?
the rubrospinal and corticospinal tracts
The rubrospinal and corticospinal tracts can be referred to as what?
the lateral motor system
What is the corticobulbar system?
a system that doesn’t travel through the spinal cord, but instead it controls the brainstem nuclei, which innervate the cranial nerves to control facial movements
Where does the corticospinal tract begin?
the primary motor cortex
What is another name for the corticospinal tract?
the pyramidal tract
Where does the rubrospinal tract begin?
a small part midbrain called the red nucleus
What is the red nucleus named after?
its pinkish appearance
What are the ventromedial pathways?
the tectospinal, vestibulospinal, reticulospinal tracts
Where does the vestibulospinal tract originate?
the vestibular organs of the inner ear, like the semicircular canals
What does the vestibulospinal tract provide information on?
the direction of gravity, spin, and other forces acting on the body and head
Where does the tectospinal tract originate from?
the roof or tectum of the midbrain
Where does the reticulospinal tract originate?
the reticular formation of the pons
What areas does the reticulospinal tract target?
the torso and the legs
What does the basal ganglia do?
it is involved with the initiation and execution of movement
What 2 diseases are involved with damage to the basal ganglia?
Parkinson’s disease and Huntington’s disease
What is a shuffling gait?
too little movement
What are spastic twitches?
too much movement
The cerebellum comes from the Latin word for ______.
little brain
Where is the cerebellum located?
the back of the brain, underneath the temporal and occipital lobes
What is the role of the cerebellum?
learning of new motor tasks and skills
How many layers does the cerebellar cortex have?
3
What type of neuron has dendrites that form a corral-like array and it nearly flat?
Purkinje cells
Where does output from the cerebellar cortex come from?
Purkinje cells
What is motor learning?
an unconscious form of learning through repetition where the brain and body adapts through feedback on a motor command
What do prism goggles do?
the shift your vision to the right
Will damage to the hippocampus erase previous long-term memories?
No, because long-term memories are not stored in the hippocampus
What does damage to both hippocampi result in?
it can result in being unable to form new long-term memories
Where are long-term memories stored?
in the area related to the memory
When did patient H.M. go through brain surgery?
the 1950s
Why did patient H.M. have both of his hippocampi removed?
to try to control his seizures
Where does most of the input for the hippocampus come from?
the entorhinal cortex
How many layers does the entorhinal cortex have?
6
On average, how many items can most people retain in their short-term memory?
5-9
What area of the brain is critical for maintaining short-term memory?
the prefrontal cortex
What 3 processes make up long-term memory?
encoding, storage, and retrieval
What is encoding when creating long-term memories?
learning or gaining the information
What is storage when creating long-term memories?
filing away the information, happens subconsciously
What is retrieval when creating long-term memories?
recalling the information
What are the 2 types of long-term memory?
explicit and implicit memory
What type of long-term memory can be consciously recalled?
explicit memory
Explicit memory can be _____ memory.
semantic memory
What is semantic memory?
facts without any context or emotions
How is explicit memory made?
through consolidation by the hippocampus
Does implicit memory use the hippocampus?
No
What is implicit memory?
unconscious and unrehearsed memory
How long does implicit memory stick around?
for a lifetime
What type of long-term memory is slow to encode?
implicit memory
What type of long-term memories was Patient H.M. able to make?
implicit memories because it doesn’t involve the hippocampus
What is procedural memory?
a subtype of implicit memory, memories associated with learned motor skills
What type of long-term memory are habits?
implicit memory
Habits rely on what structures in the brain?
the basal ganglia
What is priming?
when one stimulus influences your memory
What type of long-term memory involves emotional associations?
implicit memory
What is classical conditioning?
getting a subject to form an association between a meaningful stimulus and a neutral stimulus
Implicit memory is reliant on which brain regions?
limbic regions, like the cerebellum and amygdala (though obviously not the hippocampus)
