Psychology Flashcards
Memorize all people and laws/terms
Anterograde movement
Forward (ex. kinesin)
Retrograde movement
Backwards
Kinesin
Protein
Drives movement of vesicles and organelles along microtubules in axons
Drives anterograde movement (from soma to axon terminus)
Resting Membrane Potential
~-70mV, inside of cell negatively charged and outside of cell positively charged
Membrane proteins required to establish this: Na+/K+ ATPase (with hydrolysis of 1 ATP molecule) and K+ leak channels (allow K+ to flow down gradient out of the cell)
This leaves interior of cell with net negative charge
Cell is polarized (- inside), the becomes depolarized from AP
Change in membrane potential=from movement through ion channels into and out of the neuron=electrochemical impulse
Depolarization
Voltage-gated Na+ channels: open and allow Na+ to flow down gradient and into the cell to depolarize the membrane
Opened from depolarization of membrane from -70mV to threshold potential of -50mV, and then Na+ flow in until reaches ~35mV before inactivating
Once threshold is reached, channels are opened fully, but below threshold they are closed
Depolarization gets passed down the axon with voltage-gated Na+ channels opening when depolarization in neighboring membrane reaches potential (-50mV)
Can AP run out of energy?
NO, it will continue to propagate until it reaches end/synapse
Repolarization
Re-establishes RMP
Voltage-gated Na+ channels inactivate and voltage-gated K+ channels open (but open more slowly than Na+ channels and stay open longer)
VG K+ channels open in response to membrane depolarization
RMP overshoots to ~-90mV and voltage-gated K+ channels close
K+ leak channels and Na+/K+ ATPase continue to function to bring membrane back to resting potential
Schwann Cells
PNS, form myelin (no ions can enter where myelin is present
Oligodendrocytes
CNS, form myelin
Glial Cells
Specialized, non-neuronal cells that typically provide structural and metabolic support to neurons
Maintain a RMP but do not generate APs
Astrocytes
CNS, Guide neuronal development
Regulate synaptic communication via regulation of neurotransmitter levels
Microglia
CNS, remove dead cells and debris
Ependymal Cells
CNS, Produce and circulate CSF
Equilibrium Potential
No net movement
Ex. Na+
-Chemical gradient drives Na+ in and electrochemical gradient drives Na+ out (because inside of cell is too positive)-balance each other at 50mV
-K+ has negative equilibrium potential and driven out by conc. gradient, electrical gradient drives K+ in because inside of cell is too negative and they are attracted, chemical gradient drives K+ out
Equilibrium potential equation
Nernst: E(ion)=RT/zF ln(conc. inside/conc. outside)
- -> Relative concentrations of the ion on each side of the membrane create the chemical gradient
- -> Valence (charge of the ion) creates the electrical gradient
Absolute Refractory period
Na+ channels inactivated (NOT the same as closed)
Can’t be opened again until they return to closed state and membrane reaches resting potential
No AP
Due to inability of voltage-gated Na+ channels to open
Relative Refractory Period
Na+ channels from inactivated to closed
Membrane hyperpolarized, so needs greater depolarization
K+ channels that haven’t closed yet cause membrane potential to be more negative than resting potential
Synapses
Can be btw 2 neurons or neuron and organ
2 types: electrical and chemical
Electrical Synapses
Occur when the cytoplasms of 2 cells are joined by gap junctions
AP spreads directly from one cell to the other
More important in smooth and cardiac muscle
Chemical Synapses
Found at ends of axons where they meet target cell
Here, AP is converted into a chemical signal
Ex. neuromuscular junction
Transmission of signal across chemical synapse steps
- Ap reaches end of axon/synaptic knob
- Depolarization of presynaptic membrane open voltage-gated Ca2+ channels
- Ca2+ influx into presynaptic cell causes exocytosis of NT stored in secretory vesicles
- NT molecules diffuse across narrow synaptic cleft
- NT binds to receptor proteins in postsynaptic membrane. Receptors are ligand-gated ion channels
- Opening of ion channels (ions enter postsynaptic cell) in postsynaptic cell alters the membrane polarization (increases or decreases it)
- If membrane depolarization of postsynaptic cell reaches the threshold of voltage-gated Na+ channels, an AP is initiated
- NT in synaptic cleft is degraded and/or removed to terminate signal
Neuromuscular junction
NT released: ACh
When AP reaches synapse, ACH is released into synaptic cleft
ACH bind to ACh receptor on surface of postsynaptic membrane
When ACh binds to receptor, receptor opens Na+ channels and postsynaptic cell membrane gets depolarized
ACh left in synaptic cleft gets degraded by AChE (enzyme: acetylcholinesterase)
Other NTs
GABA, serotonin, dopamine, norepinephrine
Excitatory or inhibitory=depends on receptor, not NT
Ex. inhibitory=NT causes entry of Cl- into cell, which makes postsynaptic potential more NEGATIVE, or HYPERPOLARIZED, so NT=inhibitory
Summation
Addition of stimuli, multiple neurons that lead to synapse, how postsynaptic neuron “decides” to fire AP or not
Temporal Summation
Presynaptic neuron fires APs so rapidly that EPSPs and IPSPs pile up on each other
Spatial Summation
EPSPs and IPSPs from all synapses on postsynaptic membrane are summed at a given moment in time
PNS
Sensory function of nervous system Motor function (acting on info)
CNS
Integrative (processing info)
2 types of effectors
Muscles and glands (motor neuron that carry info AWAY nervous system)
Afferent neurons
Sensory neurons, carry info TO CNS
Muscle Stretch Reflex
Sensory neuron detects stretching of muscle , transmits an impulse to a motor neuron cell body in spinal cord
Sensory neuron synapses with a motor neuron for quads and also with an inhibitory interneuron (for hamstring motor neuron)
Monosynaptic Reflex Arc
Reflex involving only 2 neurons and one synapse
Reciprocal Inhibition
Ex. Relaxation of hamstring with contraction of quads
PNS Organization
Somatic (voluntary movement of skeletal muscle) and Autonomic (digestion, metabolism, circulation, perspiration, and other involuntary processes)
–> autonomic to (efferent portion): sympathetic (fight or flight) and parasympathetic (slow, rest and digest)
Cell bodies are ganglia
CNS
Neuronal cell bodies and bunched together to form structures called nuclei
3 Subdivisions of Brain
For, mid, and hindbrain
Spinal Cord
Site for info integration and processing
Responsible for simple spinal reflexes (muscle stretch reflex) and primitive processing like walking, urination, and sex organ functions
Hindbrain
Medulla, pons, and cerebellum
Medulla
Below pons, connects to spinal cord, relays info to other parts of the brain, regulates vital autonomic functions like blood pressure and digestive functions, also has respiratory rhythmicity center
Pons
Below midbrain, above medulla, connection point btw brain stem and cerebellum, controls some autonomic functions are coordinates movement, plays a role in balance and antigravity posture
Cerebellum
Behind pons, where complex movements are coordinated, instruction for movement from forebrain must be sent here
Damage results in poor hand-eye coordination and balance
Both this and pons receive info from vestibular apparatus in inner ear, which monitor acceleration and position relative to gravity
Midbrain
Relay for visual and auditory info and contains much of the reticular activating system (RAS), which is responsible for arousal and wakefulness
Forebrain
Includes diencephalon and telencephalon
Diencephalon
Hypothalamus and thalamus
Thalamus
Contains relay and processing centers for sensory info
Hypothalamus
Interacts directly with many parts of brain, contains center for controlling emotions, and autonomic functions, has major role in hormone production and release, primary link btw nervous and endocrine system, controls pituitary gland, so is fundamental control center for endocrine system
Telencephalon
2 separate cerebral hemispheres
Cerebrum
consists of the large, paired cerebral hemispheres
Hemispheres of cerebrum consists of cerebral cortex-outer layer of gray matter, plus an inner core of white matter connecting cortex to diencephalon
Gray matter=somas/cell bodies
White matter=myelinated axons
Frontal Lobe
Initiates all voluntary movement and is involved in complex reasoning skills and problem solving
Parietal Lobes
Involved in general sensations (touch, temperature, pressure, vibration, etc.) and in gustation (taste)
Temporal Lobes
Process auditory and factory sensation and a reimbursement involved in short-term memory, language comprehension, and emotion
Occipital Lobes
Process visual sensation
Broca’s Area
Speech Production
Wernicke’s Area
Language Comprehension
Basal Nuclei
Composed of gray matter and located deep within cerebral hemispheres
Include several functional subdivisions, but broadly function in voluntary motor control and procedural learning related to habits
Basal nuclei and cerebellum work together to process and coordinate movement initiated by the primary motor cortex; basal nuclei are INHIBITORY (prevent excess movement), while cerebellum is EXCITATORY
Limbic System
Btw cerebrum and diencephalon
Includes several substructures (amygdala, cingulate gyrus, and hippocampus) and works closely with parts of cerebrum, diencephalon, and midbrain
Important in emotion and memory
Vagus Nerve
Decreases heart rate and increases GI activity
Parasympathetic nervous system
It is a bundle of axons that end in ganglia on the surface of the heart, stomach, and other visceral organs
The many axons constituting the vagus nerve are preganglionic and come from cell bodies located in the CNS
On the surface of the heart and stomach they synapse with postganglionic neurons
Somatic PNS Anatomy What do they innervate? NT? Organization and cell bodies (ventral or dorsal part of spinal cord?)? Somatic sensory vs. somatic motor
ALL somatic MOTOR neurons innervate skeletal muscle cells, use ACh as NT, and have cell bodies in brain stem or ventral (front) portion of spinal cord
ALL somatic SENSORY neurons have long dendrite extending from sensory receptor toward soma, which is located just outside CNS in dorsal root ganglion
Dorsal Root Ganglion
A bunch of somatic (and autonomic) SENSORY neuron cell bodies located just dorsal (to the back of) the spinal cord
There is a pair of dorsal root ganglia for every segment of the spinal cord, and the dorsal root ganglia form a chain along the dorsal (back) aspect of vertebral column
They are protected within the vertebral column but are outside of the meninges, so are outside of the CNS
Axon extends from somatic sensory neuron’s soma into the spinal cord
In ALL somatic SENSORY neurons, the first synapse is in the CNS
Efferents of sympathetic and parasympathetic nervous system contain 2 types of neurons
Preganglionic nad postganglionic
Preganglionic neuron
Has cell body in brainstem or spinal cord
Sends axon to an autonomic ganglion, located outside the spinal column
In ganglion, synapses with postganglionic neuron
Postganglionic Neuron
Sends an axon to an effector (smooth muscle or gland)
ALL autonomic preganglionic neurons release ACh as NT
ALL parasympathetic postganglionic neurons also release ACh
Nearly all sympathetic postganglionic neurons release NE as NT
All sympathetic preganglionic neurons have cell bodies:
The thoracic (chest) or lumbar (lower back) regions of the spinal cord (thoracolumbar system) Preganglionic axon is short and there are only a few ganglia which are large Postganglionic cells send a long axon to the effector
All preganglionic parasympathetic neurons have cell bodies:
In the brainstem (head or cranium) or in the lowest part of the spinal cord, the sacral portion. (Craniosacral system)
Postganglionic neurons have very short axon, since cell body is close to the target
“Para long pre”
Adrenal Cortex secretes:
Cortisol and aldosterone (and some sex hormones)
Endocrine gland
Adrenal Medulla (part of what system?)
Part of sympathetic nervous system
Directly innervated by sympathetic preganglionic neurons
Sympathetic system activated, and adrenal gland is stimulated to release epinephrine (E)–hormone (because released into the bloodstream by a ductless gland), NOT a NT (like NE)
Short, rapid effects, so acts like a NT
Stimulation of the heart
Sensation or Perception: Act of receiving info
Sensation (bottom up)
Sensation or Perception: Act or organizing, assimilating, and interpreting sensory input into useful and meaningful info
Perception (top down)
Mechanoreceptors
Respond to mechanical disturbances
Ex. Pacinian corpuscles are composed of concentric layers of specialized membranes, when membranes are distorted by firm pressure on the skin, the nerve ending becomes depolarized and the signal travels up the dendrite (these are GRADED potentials, NOT APs!!)
Ex. Auditory hair cell, found in cochlea of inner ear and detects vibrations caused by sound waves
Vestibular hair cells are located within special organs called semicircular canals, also in inner ear–>their role is to detect acceleration and position relative to gravity
Ex. of autonomic mechanoreceptor would be a receptor detecting stretch of the intestinal wall
Chemoreceptors
Respond to particular chemicals
Ex. Olfactory receptors detect airborne chemicals and allow us to smell things
Gustatory receptors are taste buds
Autonomic chemoreceptors in the walls of the carotid and aortic arteries respond to changes in arterial pH, PCO2, and PO2 levels
Nocireceptors (somatic or autonomic?)
Pain receptors, stimulated by tissue injury, simplest type (chemoreceptor)
Can be somatic or autonomic
Autonomic pain receptors do not provide the conscious mind with clear pain info, but give a sensation of dull, aching pain. May also create an illusion of pain on the skin, when their nerves cross paths with somatic afferents from the skin–>referred pain
Referred pain
When autonomic pain receptors create an illusion of pain on the skin by their nerves crossing paths with somatic afferents from the skin
Thermoreceptors (autonomic or somatic?)
Stimulated by changes in temp
Autonomic and somatic examples
Peripheral thermorecpetors fall into 3 categories: cold-sensitive, warm-sensitive, and thermal nocireceptors, which detect painfully hot stimuli
Electromagnetic receptors
Stimulated by EM waves
In humans, ex. is rods and cones of retina in eye (photoreceptors)
In other animals, electro and magnetoreceptors are separate
4 properties that need to be communicated to the CNS for encoding of relevant info
Modality, location, intensity, and duration
Modality
Type of stimulus
CNS determines this by based on which type of receptor is firing
Location
Communicated by receptive field of sensory receptor sending the signal
Can be improved by overlapping receptive fields of neighboring receptors
Discrimination btw 2 separate stimuli can be improved by lateral inhibition of neighboring receptors
Intensity
Coded by the frequency of APs Dynamic range (range of intensities that can be detected by sensory receptors) can be expanded by range fractionation-multiple groups or receptors with limited ranges to detect a wider range overall (groups of receptors work together to increase dynamic range without decreasing sensory discrimination) Ex. when cones respond to different but overlapping ranges of wavelengths to detect the full visual spectrum of light
Duration (tonic vs phasic receptors)
May or may not be coded explicitly
- Tonic receptors fire APs as long as the stimulus continues, but those receptors are subject to adaptation and the frequency of APs decreases as the stimulus continues at the same level; adapt slowly to a stimulus and continue to produce APs for the duration of the stimulus
- Phasic receptors only fire APs when the stimulus begins and do not explicitly communicate the duration of the stimulus–>these receptors are important for communicating changes in stimuli and essentially adapt immediately if a stimulus continues at the same level; adapt rapidly to a stimulus
Adaptation
Decrease in firing frequency when the intensity of a stimulus remains constant
- -> nervous system is programmed to respond to changing stimuli and not constant stimuli
- **nocireceptors do NOT adapt under any circumstances
Proprioreception
refers to the awareness of self (awareness of body position); also known as kinesthetic sense
Ex. muscle spindle-a mechanoreceptor; a sensory organ designed to detect muscle stretch
Ex. golgi tendon organs-monitor tension in the tendons
Ex. joint capsule receptors-detect pressure, tension, and movement in the joints
Pitch (frequency)
Distinguished by which regions of the basilar membrane vibrate, stimulating different auditory neurons
Basilar Membrane (type of frequency and wavelength detected?)
Thick and sturdy near oval and gradually becomes thin and floppy near apex of cochlea Low frequency (long wavelength) sounds stimulate hair cells at the apex of the cochlear duct, farthest away from the oval window
How is loudness of sound distinguished?
By the amplitude of vibration
Larger vibrations cause more frequent APs in auditory neurons
Where are sound stimuli processed?
In the auditory cortex, located in the temporal lobe of the brain
Vestibular complex is made up of 3 semicircular canals:
Function? Innervated by? Info sent where?
Utricle, Saccule, and Ampullae
–>All are tubes filled with endolymph, they contain hair cells that detect motion
Function is not to detect sound but rotational acceleration of the head-they are innervated by afferent neurons which send balance info to the pons, cerebellum, and other areas
Vestibular complex monitors bth static equilibrium and linear acceleration, which contribute to your sense of balance
Surface upon which light is focused (at back of eye)
Retina
Absorbs excess light within the eye
Choroid
Fine tunes angle of incoming light so beams are focused on retina
Lens
Ciliary muscle
Varies curvature of the lens (and refractive power)
Photoreceptors are what kind of receptor cells?
Electromagnetic receptors
Which cell’s axons comprise the optic nerve?
Ganglion cells
Macula (what is in center and what is ti responsible for??)
In center is fovea centralis (focal point) which contains ONLY cones and is responsible for extreme visual acuity
Ex. staring directly at something=focusing its image on the fovea
What happens when rods and cones absorb light?
They change their tertiary structure
Each protein, called an opsin, is bound to one molecule and consigns one molecule of retinal, which is derived from vitamin A
In dark, rods and cones? (trans and cis bonds, which channels are open/closed)
In dark, rods and cones are resting, and retinal has several trans double bonds and one cis double bond
In this conf., retinal and its associated opsin keep an Na+ channel open
Cell remains depolarized
Now what happens upon absorbing a photon of light?
Retinal is converted to all trans form, which triggers a series of reactions that ultimately closes the Na+ channel, and the cell hyperpolarizes
Rods and cones depolarize in light or dark?
Dark
What happens during depolarization of rods and cones in dark?
Photoreceptors release glutamate onto bipolar cells, inhibiting them from firing
Upon absorbing a photon of light and subsequent hyper polarization, the photoreceptors stop releasing glutamate
What effect does glutamate have on bipolar cells?
Inhibitory
–>so when Glu is no longer present, the bipolar cell can depolarize (removal of inhibition causes excitation in this system)
This then causes depolarization of the ganglion cells, and an AP along the axon of the ganglion cells
Rods are more sensitive to?
Dim light and motion and more in periphery of retina
Cones are responsible for?
Color vision and high-acuity vision and are more concentrated in the fovea
Color vision depends on 3 types of cones (3 colors?)
One absorbs blue light, one green, and one red
Emmetropia
Normal Vision
Myopia
Nearsightedness
Results from too much curvature of the lens so light is focused in front of the retina; focal length is too short, too much refraction
Can be corrected by a concave (diverging) lens
Hyperopia
Farsightedness
Results from focusing of light behind the retina; focal length is too long, too little refraction
Can be corrected by a convex (converging) lens
Presbyopia
Inability to accommodate (focus)
Results from loss of flexibility of the lens, mostly happens with aging
Feature detecting neurons
Specific neurons in the brain that fire in response to particular visual features (lines, edges, angles, movement)
Feature-detection Theory
Explains why a certain area of the brain is activated when looking at a face, and a different area is activated when looking at letters on a page, etc.
Parallel Processing
What our brain does in order to process vast amounts of visual info quickly and effectively; many aspects of a visual stimulus (form, color, motion, depth, etc.) are processed simultaneously instead of in a step by step fashion
Which lobe constructs a holistic image by integrating all of the separate elements of an object, in addition to accessing stored info?
Occipital Lobe
Depth Perception
The ability to see objects in 3D despite the fact that images are imposed on the retina in only 2D
–> Allows us to judge distance
Ex. visual cliff experiment with babies–depth perception is largely innate
What do binocular and monocular cues help us do?
They are responsible for our ability to perceive depth and distance
Binocular Cues
Depth cues that depend on info received from both eyes and are most important for perceiving depth when objects are close to us in our visual field
Retinal Disparity
A binocular cue where the brain compares the images projected onto the 2 retinas in order to perceive distance
- -> the greater the difference or disparity btw the 2 images on each retina, the shorter the distance to the observer
- -> farther images have less disparity (the images on each retina are more similar indicating that the object is farther away), while closer images have more disparity, indicating that to your brain that they are closer to your face
Convergence
A binocular cue that describes the extent to which the eyes turn inward when looking at an object
–> The greater the angle of convergence or inward strain, the closer the object
Monocular Cues
Depth cues that depend on info that is available to either eye alone and are important for judging distances of objects that are far from us since the retinal disparity is only slight
What do we rely on (types of cues) for objects at farther distances?
CanNOT rely on binocular cues for objects at farther distances, so rely on any combination of monocular cues
Relative Size
If objects are assumed to be the same size, the one that casts the smaller image on the retina appears more distant
Interposition
If one object blocks the view of another, we perceive it as closer
Relative Clarity
We perceive hazy objects as being more distant than sharp, clear objects
Texture Gradient
Change from a coarse, distinct texture to a fine, indistinct texture indicates increasing distance
Relative Height
Yep perceive objects that are higher in the visual field as farther away
Relative Motion
As we move, stable objects appear to move as well; objects that are near to us appear to move faster than objects that are farther away
Linear Perspective
Parallel lines appear to converge as distance increases
–> the greater the convergence, the greater the perceived distance
Light and Shadow
Closer objects reflect more light than distant objects
Absolute Threshold
The minimum stimulus intensity required to activate a sensory receptor 50% of the time (and thus detect sensation)
–> important for detecting the presence of absence of stimuli
Difference Threshold
Also called JND, the minimum noticeable difference between any 2 sensory stimuli, 50% of the time
Important for the ability to determine the change or difference in stimuli is also vital
Weber’s Law
2 stimuli must differ by a constant proportion in order for their difference to be perceptible
–> We perceive difference on a logarithmic, not linear scale, it is not the amount of change but the percentage change that matters
Signal Detection Theory (4 possible outcomes)
Attempts to predict how and when someone will detect the presence of a given sensory stimulus (the signal) amidst all of the other sensory stimuli in the background (the noise)
4 possible outcomes:
1. A hit: the signal is present and was detected
2. A miss: the signal was present but not detected
3. A false alarm: the signal was not present but the person thought it was
4. A correct rejection: the signal was not present and the person did not think it was
Gestalt (and what does it not do??)
An organized whole perceived as more than the sum of its individual parts
The whole exceeds the sum of its parts-when humans perceive an object, rather than seeing it as lines, angles, colors, shadows, etc., they perceive the whole
BUT does NOT explain HOW the brain is able to perceive in such a way, merely that it does
Emergence
When attempting to identify an object, we first identify its outline, which then allows us to figure out what the object is; we identify the parts AFTER the whole emerges
Figure/ground
Describes our perceptual tendency to separate the figure or object from everything else (the background) based on a number of possible variables, like size, shadow, contrast, color, etc.
–> everything that is not figure is ground
Multistability
The tendency of ambiguous images to pop back and forth unstably btw alternative interpretations in our brains
Gestalt Laws of Grouping
Law of proximity, law of continuity, law of closure, law of common fate, law of connectedness, law of similarity
Law of Proximity
Things that are near each other seem to be grouped together; nearby objects tend to be perceived as a unit or group
Law of similarity
Things that are similar tend to appear grouped together; we tend to perceive similar items as a unit or group
Law of Continuity
Points that we perceive the smooth, continuous lines and forms, rather than disjointed one
Law of Closure
We will perceive things as a complete, logical entity because our brains fill in the gaps in the info
Law of Common Fate
Objects moving in the same direction or moving in synchrony are perceived as a group or unit
Ex. group of dancers or flock of birds all moving together
Law of Connectedness
Things that are joined or linked or grouped are perceived as connected
Bottom-up Processing
Begins with the sensory receptors and works up to the complex integration of info occurring in the brain
Also known as data-driven processing-info enters the eye in one direction (this sensory input is the “bottom”) and is then turned into an identifiable image by the brain (this final image is the “top”)
–> We tend to use this approach when we have no or little prior experience with a stimulus
Top-down Processing
Occurs when the brain applies experience and expectations to interpret sensory info
Instead of focusing on the sensory input (the bottom), we sue prior experience and knowledge to impose our expectations on the stimulus, which tends to occur with stimuli we are more familiar with
–> Brain uses a combo of the two: info is received in a bottom-up fashion from sensory receptors while the brain is superimposing assumptions in a top-down manner
