chapter 3 - biological psychology

Question 1

what two channels define the resting membrane potential

Answer 1

sodium potassium atpase and K+ leak channels

Question 2

what is threshold potential roughly equal too in neurons

Answer 2

-55 mV and RMP is around -70

Question 3

true or false, the amount of energy consumed by sodium potassium pumps is less in myelinated neurons then un-myelinated

Answer 3

true and false
Energy per pump does not change.

however, myelinated neurones only have to deal with nodes of Ranvier (i.e. less pumps, less total energy)

Question 4

what are astrocytes and ependymal cells?

Answer 4

types of glia cells (support cells for neurons)

astrocytes - guide cells / neurotransmitter regulators / help make the blood brain barrier
ependymal cells - produce CSF

Question 5

what defines the absolute and relative refractory periods?

Answer 5

absolute - the neuron will not fire no matter what: voltage gated sodium channels are inactivated

relative - during hyper-polarization where causing a depol takes more effort but is possible

Question 6

what is electrical synapse? what is chemical synapse?

Answer 6

electrical synapse = gap junctions

chemical = neurotransmitters

Question 7

what are nuclei and ganglia of the nervous system?

Answer 7

nuclei are a collection of soma’s within the CNS

ganglia are a collection of soma’s within the PNS (peripheral)

Question 8

the brain has three main “parts” the hindbrain, midbrain, and forebrain. What makes up the hindbrain? what do these parts do/process?

Answer 8

the hindbrain is made up of the…
1) medulla: connects brain to SC. It is a relay centre and has the respiratory control centre which senses carbon dioxide in the blood

2) pons: involved in movement and posture
3) cerebellum: coordinates complex movement and regulates muscle tone along with the basal nuclei

Question 9

the brain has three main “parts” the hindbrain, midbrain, and forebrain. What makes up the midbrain? what do these parts do/process?

Answer 9

the midbrain has no key “parts” however it is responsible for auditory and visual processing and eye movement.

it also contains the reticular activating system (RAS) responsible for wakefulness

Question 10

what is the brain stem?

Answer 10

the medulla, pons, and midbrain

Question 11

the brain has three main “parts” the hindbrain, midbrain, and forebrain. What makes up the forebrain? what do these parts do/process?

Answer 11

the forebrain is made up of the diencephalon and telencephalon.

the diencephalon is made up of the thalamus (sensory centre) and hypothalamus (homeostasis)

the telencephalon is made up of the cerebrum which is really the two cerebral hemispheres for higher level thinking

Question 12

what is the corpus callosum?

Answer 12

a thick bundle of axons that separates the two cerebral hemispheres.

Question 13

what is the role of the basal nuclei?

Answer 13

regulates voluntary motor control along with the cerebellum and pons (pons is also more involuntary)

Question 14

true or false the basal nuclei and cerebellum are inhibitory and the cortex is excitatory.

Answer 14

true. Note that no motor neurons are inhibitory. The signals of the cerebellum / basal nuclei slow down the excitatory motor signals (smooths out movement)

Question 15

what is the limbic system? what is it composed of? (3)

Answer 15

1) hippocampus –> memory

2) amygdala –> emotion `

Question 16

is the vagus nerve a SNS or PNS nerve?

Answer 16

PNS therefore it slows heart rate (actively slowing it actually) and increases GI activity

Question 17

there are two types of somatic nerves: motor and sensory. Explain the characteristics of each (soma location, innervation, nt, etc
0

Answer 17

motor nerves: all innervate skeletal muscle, release acetylcholine, and have ventral root soma’s

sensory: attached to sensory receptors. Their soma’s are found outside the CNS in dorsal root ganglia.
note: ventral = front of SC, dorsal = back of SC

Question 18

what is the meninges?

Answer 18

protective sheath for the CNS. the dorsal root ganglia for ANS nerves and sensory somatic nerves lives outside the meninges

Question 19

explain the general structure of ANS neurons

Answer 19

There are many pre-ganglionic neurons all having their cell bodies in the CNS. They have axons that extend to the PNS and synapse (releasing Ach) with a post-ganglionic neuron. Then PNS post-G will release Ach and SNS post-G will release NE

Question 20

what sections of the spinal cord do PNS and SNS soma’s exist in? what are the relative lengths of the pre and post axons for the SNS and PNS

Answer 20

SNS
soma’s located in the thoracic and lumber regions
SNS have short pre-ganglionic axons and long post-ganglionic axons

PNS
soma’s located in the craniosacral regions (top and bottom)
PNS pre-ganglionic axons are long asf and they’re post-ganglionic axons are short (PNS post-ganglionic soma’s for the intestine are on the all of the intestine– therefore pre axon must be long)

Question 21

what are opsin and retinal? Explain the different forms of retinal in light and dark.

Answer 21

Opsin is a protein which is bound to one molecule of Retinal. Their complex is in conjunction with sodium influx channels of rods and cones.

In the absence of light, retinal has both cis and trans bonds which keeps it bound to opsin and keeps the sodium channel open. (therefore the photoreceptor is depolarized and releases glutamate)

when light is perceived, the retinal assumes an “all trans form” which eventually causes the closure of the sodium channel. (now hyper polarized)

Question 22

Explain On centre and Off centre bipolar cells

Answer 22

On centre Bipolar cells: These cells are inhibited by glutamate (i.e. inhibited in the dark)
When light hits the photoreceptor, less glutamate is released and the on centre bipolar cell fires to the ganglion cell.

Off centre bipolar cells: These cells are stimulated by glutamate (i.e. stimulated in the dark). When light comes in and lowers the amount of glutamate, these cells stop firing

Question 23

what is emmetropia, myopia, and hyperopia?

Answer 23

emmetropia –> normal vision

myopia –> near sightedness (the light converges before the retina)

hyperopia –> far sightedness (light converges after retina)

Question 24

what is presbyopia?

Answer 24

when you can no longer adjust your lens aka accommodate

Question 25

What is feature detection theory and parallel processing?

Answer 25

feature detection theory –> essentially explains that different parts of the brain are used for different visual inputs
it accounts for feature detecting neurons which detect lines, edges, shapes, etc. These combine and eventually become complex images. (feature detection explains why different brain area’s process the face and a book)

parallel processing explains that we integrate multiple stimuli and process them simultaneously rather than step by step. It also states that simultaneously we pull up memory to aid in visual recognition

Question 26

Explain what depth perception is.

Answer 26

depth perception is the ability to see three dimensional images even though the retina displays 2D images.

Question 27

Binocular an mononuclear cues are why we have depth perception. The two binocular cues are retinal disparity and convergence. Explain each.

Answer 27

retinal disparity - each retina of each eye processes an image itself and the brain integrates both eyes. However each retina does not send the same image.

close objects have high retinal disparity (i.e. the two images sent by the 2 retinas are very different)

far objects have low retinal disparity (both retina’s perceive similar images)
depedning on retinal disparity we can guess the distance of an object.

convergence –> as something gets closer to our eyes, our eyes physically move inward. the more they do this, the closer an object is. (mid brain controls eye movement)

Question 28

monocular cues are used when objects are far away since retinal disparity is too small. Explain 
relative size 
interposition 
relative clarity 
texture gradient
relative height 
relative motion 
linear perspective 
light and shadow

Answer 28

relative size –> objects assumed to be the same size (two basketballs) If one appears smaller then its further.
interposition —> if one object obstructs the view of another it must be closer

relative clarity –> clear objects = close
texture gradient –> same as above
relative height –> objects at the bottom of our eyes such as by our feet are closer
relative motion —> when we move, close objects seem to wiz by faster
linear perspective –> parallel lines converge at distance
light and shadow —> bright appears closer than dark

Question 29

what are the absolute and difference thresholds? what is Weber’s law?

Answer 29

absolute threshold –> the amount of stimulus required to activate the sensory receptor 50% of the time. this determines absence of presence of stimulus

difference threshold –> the amount a stimulus must change by to activate sensory receptors 50% of the time.

difference threshold is governed by Weber’s law which states for each stimuli, the stimulus must change by a fixed proportion each time..

e.g. for vision, light intensity much alter by at least 8% each time to notice a difference.

Question 30

What is signal detection theory. Note: feature detection theory explains how different area’s of the brain process different images.

signal DT is different! (hint: 4 answers in signal dt test)

Answer 30

signal detection theory explains the ability to notice a stimulus amidst all the other stimuli in the background. When testing this theory, there are 4 responses.

1. hit - stimuli present and accounted for
2. miss - stimuli present but not accounted for
3. false(+) - no stimuli but was perceived
4. correct rejection - no stimuli and was not perceived

Question 31

what does gestalt psychology encompass?

Answer 31

gestalt psychology explains that we do not perceive objects as their individual parts (i.e. colour, lines, edges) but rather we perceive them as a whole

Question 32

Random Q: what is top-down and bottom-up processing?

Answer 32

top-down processing –> your perception is driven by cognition. Your brain applies what it already knows and what it expects and then fills in the blanks

bottom-up processing–> processing that begins with sensory receptors and works its way up to complex integration.

the brain uses both in parallel processing

Question 33

Gestalt psychology: explain emergence

Answer 33

emergence is the Gestalt principle that explains when we first observe an object / photo, we first perceive its outline as a whole before noticing its parts.

• if you looked an a picture of a dog, prior to noticing its paws, collar, and eyes, you notice that it is a dog. The whole image “emerges” first.

Question 34

gestalt psychology: explain Figure/ground

Answer 34

this is the Gestalt principle in which once an emerged image has been seen, it is viewed as the main figure while everything else is seen as the background

Question 35

Gestalt psychology: explain multistability

Answer 35

the occurrence of your brain switching back

and forth between perceptions when an object / image appears to be ambiguous

Question 36

Gestalt grouping laws:

explain: The law of proximity

Answer 36

things bundled closely together are perceived to be grouped together. If a bunch of circles are placed in a square our brain perceives the square made of circles

Question 37

Gestalt grouping laws:

explain: The law of similarity

Answer 37

similar objects are grouped together

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law of proximity makes us see a rectangle
law of similarity makes us see rows

Question 38

Gestalt grouping laws:

explain: The law of continuity

Answer 38

essentially, this law explains that we try to perceive things that are smooth and continuous rather than disjointed.

Question 39

Gestalt grouping laws:

explain: The law of closure

Answer 39

the law of closure explains that we often use logic to fill in the gaps if they are missing in an object.

essentially the image we see does’nt exist but we place it there to make the image logical

Question 40

Gestalt grouping laws:

explain: The law of common fate

Answer 40

objects moving in the same direction are perceived as a group. Like the flying V of birds

Question 41

Gestalt grouping laws:

explain: The law of connectedness

Answer 41

objects connected or grouped in some way are perceived as their own unit.