Biological Foundations of Behaviour Part II

Question 1

exteroceptors

Answer 1

sensory receptors that detect stimuli from the outside world

Question 2

interoceptors

Answer 2

receptors that respond to internal stimuli

Question 3

mechanoreceptors

Answer 3

respond to mechanical disturbances (ex. Pacinian corpuscles, auditory hair cell, vestibular hair cell)

Question 4

chemoreceptors

Answer 4

respond to particular chemicals (ex. olfactory receptors, gustatory receptors)

Question 5

nociceptors

Answer 5

pain receptors, stimulated by tissue injury, consists of a free nerve ending

Question 6

referred pain

Answer 6

the illusion of pain on the skin created by nociceptors when their nerves cross paths with somatic afferents from the skin

Question 7

thermoreceptors

Answer 7

stimulated by changes in temperature

Question 8

electromagnetic receptors

Answer 8

stimulated by electromagnetic waves (photoreceptors)

Question 9

what are four properties of sensory information that need to be communicated to the CNS?

Answer 9

1) modality (type of stimulus-based on which receptor is firing)
2) location (communicated by the receptive field of the sensory receptor sending the signal)
3) intensity (frequency of action potentials)
4) duration

Question 10

tonic receptors

Answer 10

fire action potentials as long as the stimulus continues (subject to adaptation, frequency of action potentials decrease as stimulus continues at the same level)

Question 11

phasic receptors

Answer 11

only fire action potentials when the stimulus beings, do not explicitly communicate the duration of the stimulus

Question 12

adaptation

Answer 12

decrease in firing frequency when the intensity of a stimulus remains constant

Question 13

which receptors do not adapt under any circumstances?

Answer 13

nociceptors

Question 14

proprioception

Answer 14

awareness of the self (body position), aka: kinesthetic sense, ex. muscle spindle, Golgi tendon organs, joint capsul receptors

Question 15

pitch

Answer 15

(frequency of sound), distinguished by which regions of the basilar membrane vibrate, stimulating different auditory neurons

Question 16

where do low frequency wavelengths vibrate the basilar membrane?

Answer 16

near the apex of the cochlear duct, farthest away from the oval window

Question 17

where do high frequency wavelengths vibrate the basilar membrane?

Answer 17

at the base of the cochlea, near the oval window

Question 18

loudness

Answer 18

distinguished by amplitude of vibration, larger vibrations cause more frequent action potentials in auditory neurons

Question 19

auditory cortex

Answer 19

located in the temporal lobe of the brain, processes sound

Question 20

what does the vestibular complex consist of?

Answer 20

3 semicircular canals, the utricle, the saccule, and the ampullae

Question 21

what does the vestibular complex monitor?

Answer 21

static equilibrium and linear acceleration to contribute to balance

Question 22

rods and contes contain photopigments called opsin which is bound to one molecule and contains one molecule of retinal, what is its conformation in the dark?

Answer 22

several trans double bonds and one cis double bond: keeps sodium channels open, cell remains depolarized, release glutamate to bipolar cells (inhibitory), prevents optic nerves from depolarizing

Question 23

what is the conformation of retinal upon absorption of light?

Answer 23

all-trans: closes sodium channel, cell is hyperpolarized, does not release glutamate to bipolar cells, bipolar cells depolarize, optical nerve signals to CNS

Question 24

emmetropia

Answer 24

normal vision

Question 25

myopia

Answer 25

nearsightedness, caused by too much refraction (short focal length) or abnormally long eyeball, corrected by concave lens

Question 26

hyperopia

Answer 26

farsightedness, caused by too little refraction (long focal length) or an abnormally short eyeball, corrected by convex lens

Question 27

feature-detection theory

Answer 27

visual cortex fires in response to very specific information, this info is then passed on to other neurons that begin to assimilate these distinct features into more complex objects

Question 28

parallel processing

Answer 28

many aspects of a visual stimulus are processed simultaneously instead of in a step-by-step fashion

Question 29

depth perception

Answer 29

the ability to see objects in three dimensions, determined by binocular and monocular cues

Question 30

binocular cues

Answer 30

depth cues based on information received from both eyes, most important for perceiving depth when objects are close to us in our visual field

Question 31

retinal disparity

Answer 31

a binocular cue whereby the brain compares the images project onto the two retinas in order to perceive distance

Question 32

converge

Answer 32

binocular cue that describes the extent to which the eyes turn inward when looking at at object

Question 33

monocular cues

Answer 33

depth cues that depend on information 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

Question 34

what are some monocular cues?

Answer 34

relative size, interposition, relative clarity, texture gradient, relative height, relative motion, linear perspective, light and shadow

Question 35

absolute threshold

Answer 35

the minimum stimulus intensity required to activate a sensory receptor 50% of the time (and thus detect the sensation)

Question 36

difference threshold

Answer 36

the minimum noticeable difference between any two sensory stimuli, 50% of the time (aka just noticeable difference JND)

Question 37

Weber's law

Answer 37

two stimuli must differ by a constant proportion in order for their difference to be perceptible, the exact proportion varies by stimulus

Question 38

signal detection theory

Answer 38

attempts to predict how and when someone will detect the presence of a given sensory stimulus amidst all of the other sensory stimuli in the background

Question 39

Gestalt

Answer 39

refers to the idea that the whole exceeds the sum of its part; describes perceptual organization but not how this perception occurs

Question 40

Gestalt Laws of Groupings

Answer 40

several laws meant to help explain how we tend to perceive things

Question 41

law of proximity

Answer 41

things that are near each other seem to be grouped together

Question 42

law of continuity

Answer 42

perceive smooth, continuous lines and forms rather than disjoined ones

Question 43

law of closure

Answer 43

perceive things as a logical entity because brain will fill in the gaps in the information

Question 44

gestalt law of common fate

Answer 44

objects moving in the same direction or moving in synchrony are perceived as a group or unit

Question 45

law of connectedness

Answer 45

things that are joined or linked or grouped are perceived as connected

Question 46

bottom-up processing

Answer 46

begins with the sensory receptors and works up to the complex integration of information occurring in the brain; more used when we have no or little experience with a stimulus

Question 47

top-down processing

Answer 47

when the brain applies experience and expectations to interpret sensory information; more used when stimuli is familiar

Question 48

hormone

Answer 48

a molecule which is secreted into the bloodstream by an endocrine gland, and which has its effects upon distant target cells possessing the appropriate receptor

Question 49

endocrine gland

Answer 49

a ductless gland whose secretory products are picked up by capillaries supplying blood to the region

Question 50

exocrine glands

Answer 50

secrete products into the external environment by way of ducts, which empty into the gastrointestinal lumen or to the external world

Question 51

hormone receptor

Answer 51

a polypeptide that possesses a ligand-specific binding site

Question 52

what determines tissue-specificity of hormone action?

Answer 52

whether the cells of a tissue have the appropriate receptor

Question 53

autocrine

Answer 53

describes activity of some signalling molecules that are able to modify the activity of the cell which secreted them

Question 54

what are the two classes of hormones?

Answer 54

hydrophilic hormones (peptides, amino acid derivatives that bind to receptors on the cell surface) and hydrophobic hormones (steroid hormones that bind to receptors in the cellular interior)

Question 55

peptide hormones

Answer 55

synthesized in the rough ER, modified in the Golgi, stored in vesicles until needed (release by exocytosis), dissolve in plasma, the first messenger which must bind to a cell-surface receptor, initiates a second messenger cascade causing signal amplification and changing the activity of many enzymes in the cytoplasm

Question 56

steroid hormones

Answer 56

synthesized from cholesterol in the smooth ER, diffuses into bloodstream as soon as made (not made if not needed), sticks to proteins in the plasma through hydrophobic interactions, diffuses through plasma membrane to bind with a receptor in the cytoplasm, steroid hormone-receptor complex acts as a sequence-specific regulator of transcription to change the amount/type of proteins in the cell

Question 57

tropic hormones

Answer 57

hormones that regulate hormones

Question 58

feedback regulation applies to:

Answer 58

tropic hormones as well as to direct regulators of physiological endpoints

Question 59

negative feedback/feedback inhibition

Answer 59

the result of hormone secretion inhibits further secretion

Question 60

which portion of the brain controls much of the endocrine system?

Answer 60

hypothalamus, controls by releasing tropic hormones (releasing and inhibiting factors/hormones) that regulate other tropic hormones

Question 61

hypothalamic-pituitary control axis

Answer 61

the hypothalamus exerts control of the pituitary by secreting hormones into the bloodstream (a unique circular miniature circulatory system) to transport hypothalamic releasing and inhibiting factors to the anterior pituitary

Question 62

hypothalamic-pituitary portal system

Answer 62

the blood supply between hypothalamus and pituitary: consists of two capillary beds in sequence that allows for direct communication between structures

Question 63

hypophysis

Answer 63

another name for pituitary gland

Question 64

anterior pituitary

Answer 64

adenohypophysis; normal endocrine gland, controlled by hypothalamic tropic hormones

Question 65

posterior pituitary

Answer 65

neurohypophysis; composed of axons which descend from the hypothalamus

Question 66

neuroendocrine cells

Answer 66

neurons which secrete hormones into the bloodstream, ex. the hypothalamic neurons that send axons down to the posterior pituitary

Question 67

what are the hormones of the posterior pituitary?

Answer 67

ADH and oxytocin