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Neurophysiology > Unit 2 > Flashcards

Unit 2 Flashcards

1
Q

_______ pain is felt within 0.1 seconds after a stimulus is applied. Not felt in most deep tissues of the body such as the viscera.

A

Fast pain

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2
Q

______ pain is sharp, prickling, acute, electric

A

Fast pain

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3
Q

_____ pain is felt more than 1 sec after the stimulus is applied

A

Slow pain

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4
Q

_____ pain can arise in almost any tissue. Manifests as burning, aching, dull, throbbing, nauseous, chronic

A

Slow pain

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5
Q

What is the sensory ending type of pain receptors?

A

Free nerve endings

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6
Q

The stimuli of pain receptors that makes it polymodal are ______, ______ and _____

A

Mechanical
Thermal
Chemical

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7
Q

______ and ______ stimuli manifest as fast and slow pain

A

Mechanical and thermal

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8
Q

______ sitmuli stimulate slow pain only

A

Chemical

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9
Q

what are some examples of chemical stimuli that stimualte pain (8)

A 
Bradykinin
Serotonin
Histamine
Poteolytic enzymes 
K+ 
Acids
Ach
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10
Q

What are 2 examples of chemicals that lower pain threshold?

A

Prostaglandins and substance P

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11
Q

Pain is ______. In the sense that the nociceptors will fire as long as the stimulus is present

A

Non-adapting

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12
Q

When pain intensity increases it is referred to as ______

A

Hyperalgesia

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13
Q

________ ____ pain manifest from mechanical or thermal stimuli and are more likely to react immediately

A

Fast sharp pain

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14
Q

Fast sharp pain transmits from ______ fibers and involved in quick immediate reactions

A

Adelta fibers

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15
Q

_____ _____ pain is mostly by chemical stimuli but also by persistent thermal or mechanical stimuli

A

Slow dull pain

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16
Q

Slow dull pain is transmitted through _______ fibers and is more likely to intensify over time

A

C type fibers

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17
Q

Slow dull pain is transmitted through _______ fibers and is more likely to intensify over time the neospinothalamic tract pain type and fiber

A

Fast pain

Adelta fibers

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18
Q

Where does the first order neuron terminate in the neospinothalamic tract?

A

Lamina 1 of the dorsal horn

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19
Q

Describe the second order neuron of the neospinothalamic tract

A

Second order neuron decussates through the anterior commissure to ascend the anterolateral tracts

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20
Q

In the neospinothalamic The second order neuron decussates through the _________ to ascend the _______tracts

A

Anterior commissure

Anterolateral tracts

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21
Q

In the neospinothalamic tract. The second order neuron terminations:
Some fibers end in the _______
Most fibers terminate in the _____

A

Some fibers end in the reticular area of the brain stem

Most terminate in the VPL ( or VPM for the head) of the thalamus

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22
Q

In the neospinothalamic tract the third order neuron projects from the _______ to the _____

A

Thalamus to the somatosensory cortex

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23
Q

In _________ tract. Fairly accurate localization with the help of simultaneous activation of neighboring tactile sensory activation

A

Neospinothalamic

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24
Q

What NT is released in the neospinothalamic tract?

A

Glutamate

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25
Q

_______ tract is associated with slow chronic pain (C fibers)

A

Paleospinalthalamic tract

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26
Q

First order neurons of the paleospinothalmic tract terminate in lamina ______ and ______ (________ of the anatomical naming system.

A

II and III

Substantia gelatinosa

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27
Q

In the paleospinothalamic tract, several interneurons connect laminas _____ and ______ with lamina _____

A

II and III with lamina V

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28
Q

In the paleospinothalamic tract, second order neurons decussate to the opposite side through the ________ and ascend via the ______

A

Decussate through the anterior commissure

Ascend via the anterolateral pathway

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29
Q

In the paleospinothalamic tract, what is the NT released in the cord?

A

Substance P

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30
Q

In the paleospinothalamic tract , most second order neurons terminate in what 3 areas?

A

Reticular formation of the brain stem
Tectal area of midbrain
Periaqueductal gray region

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31
Q

A FEW 2nd order neurons pass all the way to the ______

A

Thalamus

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32
Q

The __________ tract has poor localization of the source of the stimulus

A

Paleospinothalamic tract

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33
Q

Pain not ONLY is perceived in the ______ gyrus, but also in primitive areas as well such as the _____ , ______ and ______

A

Post central gyrus

Cortex, Thalamus and brain stem

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34
Q

The cortex of the brain interprets what component of pain?

A

Pain quality

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35
Q

The thalamus and brain stem feels what aspect of pain?

A

The unpleasantness/ suffering aspects of pain

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36
Q

Pain participates in the _____ system of the brain

A

Arousal

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37
Q

What two levels can pain perception be modified?

A

At the level of the brain and at the level of the spinal cord

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38
Q

How is pain perception modified at the level of the brain?

A

Analgesia system involves endogenous opiates

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39
Q

How can pain perception be modified at the level of the spinal cord?

A

By the gate control theory

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40
Q

what are the 4 components of the central analgesia system?

A

Periventricular nulcei
Peri-aqueductal gray
Raphe magnus nulceus
Pain inhibitory complex

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41
Q

Of the central analgesia parts, the perventricular nulcei in the __________ surrounds the _______

A

Hypothalamus

3rd ventricle

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42
Q

Of the central analgesia parts, the peri-aqueductal gray surround aqueduct in the _______ and _______

A

Midbrain and upper pons

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43
Q

Of the central analgesia parts, the Raphe magnus nulceus is a thin midline nulceus in _________ and _______

A

Lower pons and upper medulla

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44
Q

Of the central analgesia parts, the pain inhibitory complex is in the _______

A

Dorsal horn of the spinal cord

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45
Q

______ and ______ secreting neurons are a key component in pain modulation in the central analgesia parts

A

Enkephalins - endogenous opiates

Serotonin

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46
Q

What activates the analgesia system?

A

Stress/limbic system

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47
Q

What can activate the analgesia system?

A

Both the stress of pain and the psychological.emotional state of the individual
Stress also activates the sympathetic NS and ACTH/cortisol release

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48
Q

Pain pathways terminate in many of the same areas that are part of the __________. Therefore pain pathways may lead to their own _____

A

Analgesia system

Inhibition

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49
Q

What are the 3 families of mediators of analgesia?

A

Enkephalins
Endorphins
Dynorphins

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50
Q

_______ is a precursor to endogenous opioid peptides called MSH and ACTH and beta-endorphin

A

POMC (pro-opiomelonocortin)

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51
Q

What occurs in gate control theory?

A

With gate control add in sensation from skin and mechanoreceptors. It has a side branch (lateral branch) that goes to the inhibitory neuron. So it excites an hibitory neuron which results in inhibition
When the mechanoreceptor are stimulated it tend to weak the stimulus up to the thalamus.

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52
Q

When you feel pain from an injury and you shake the body part or rub the area instinctively is referred to as an example of ___________

A

Gate control theory

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53
Q

__________ is where pain from a visceral organ is referred to a body surface

A

Referred pain

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54
Q

What is the mechanism of referred pain?

A

Visceral pain fibers and skin nerve fibers converge on the same second order neuron where cross talk can occur effect the dermatomes of the same spinal level.

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55
Q

________ is where the pain refers to the dermis that shares the same embryonic spinal level as the visceral organ and is a big part of the mechanism of referred pain.

A

Dermatomal rule

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56
Q

_______ is pain orignating in a visceral structure perceived as being from an area of skin innervated but the same segmental level as the visceral afferent

A

Referred pain

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57
Q

What does referred pain result from?

A

Cross talk in the dorsal horn where the convergence of somatic and visceral afferents on the same segmental level of the SC

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58
Q

Some referred pain from viscera follows ________ innervated by the same spinal nerves

A

Dermatomes

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59
Q

What are 5 causes of visceral pain?

A 
Ischemia 
Chemical damage 
Spasm of smooth muscle in a hollow organ 
Excessive distension of a hollow organ 
Stretch of visceral CT
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60
Q

_______ fibers are involved with visceral pain and transit ______ type of pain

A

C type fibers

Chronic-aching- suffering type of pain

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61
Q

______ is accumulation of acidic metabolic end products, bradykinin and proteolytic enzymes

A

Ischemia

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62
Q

What are the viscera that are insensitive to pain?

A

Parenchyma of the liver (ex: hepatocytes)
alveoli of the lungs
Brain

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63
Q

What are examples of viscera that ARE sensitive to pain?

A

Peritoneum
Bile ducts
Bronchi
Pleura

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64
Q

Are Blood vessels (dural sinuses and middle meningeal artery) and meninges sensitive to pain?

A

Yes

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65
Q

Visceral disease leads to _______ pain

A

Poorly localized dull pain

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66
Q

Visceral disease causes _____ pain when inflammation spreads to partietal serous membranes

A

Sharp more localized pain
AKA parietal pain

Visceral disease can cause parietal pain

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67
Q

An intracranial headache has a pain referral pattern. Above the tentorum, pain is referred to the ______
Below the tentorum, pain is referred to ______

A

Forehead

Occipital area

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68
Q

An extracranial headache is referred to the _______

A

Face behind the eyes

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69
Q

What are examples of causes of intracranial headaches?

A 
Meningitis
Low CSF pressure
Migraines 
Cluster headaches 
Alcohol
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70
Q

What are the extracranial causes of head aches?

A

Tension head aches
Nasal or sinus infection
Eye disorders

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71
Q

What are 4 types of head aches?

A

Sinus
Cluster
Tension
Migraine

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72
Q

______ head aches, pain is behind browbone and or cheeks

A

Sinus head ache

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73
Q

_______ headaches, pain is in and around one eye

A

Cluster head aches

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74
Q

______ headaches, pain is like a band squeezing the head

A

Tension

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75
Q

________ headaches, pain, nausea and visual changes are typical of classic form

A

Migraine

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76
Q

________ is the other part of the anterolateral system other than pain

A

Temperature/ thermal modalities

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77
Q

Thermoreceptors exhibit ______, feel abrupt change in temperature (especially cold) then subsides

A

Adaptation

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78
Q

Swings in temperature that occur due to _________ are usually not perceived. 31-36 degrees Celsius (88-97 degrees F)

A

Thermoregulation

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79
Q

_______ is body temperature regulation by vasomotoion of cutaneous blood vessels

A

Thermoregulation

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80
Q

________ has to do with the rate light is absorbed by atoms and re-emitted as light as it passes through a medium

A

Optical density

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81
Q

_______ is a common way to express the optical density of an object by comparing the density of medium in question with a vacuum

A

Refractive index

Velocity of light in vacuum/ velocity of light in medium

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82
Q

Describe refraction of light as it enters a medium perpendicularly

A

Light that enters a medium perpendicular to the surface of a medium slows but goes in a straight line

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83
Q

Describe refraction of light that enters a medium at an angle

A

Light that enters at an angle bends.

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84
Q

The degree of bending of light as it enters a medium at an angle depends on what 2 things?

A

The ratio of 2 refractive indices of the material involved

The degree of angulation of the second medium

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85
Q

_______ lenses causes convergence of light (______)

A

Convex lenses; focuses

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86
Q

__________ is the point away from the lens that light converges into one spot

A

Focal point

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87
Q

_________ is the distance from the lens to the focal point

A

Focal length

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88
Q

If you change the curvature of the lens, you can change the _________

A

Focal length

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89
Q

_________ lenses cause divergence of light

A

Concave

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90
Q

Light rays from a close POINT source is ________ as it hits the lens

Light rays from a DISTANT source are ________ as it hits the lens

A

Diverging

Parallel

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91
Q

Near point focal lengths is _______ (length)

A

Longer

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92
Q

To shorten a focal point for a near source a more ________ lens is needed

A

Convex

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93
Q

An _____ is a mosaic of many point sources

A

Image formation

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94
Q

As light from each point source is projected through a convex lens the image is _________

A

Inverted

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95
Q

Image detector (_______, ______) must be lined up at the __________ to create a sharp image

A

Film, retina

Focal points

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96
Q

The more a convex lens can be light, the ________ its refractive power

A

Greater

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97
Q

Refractive power is measured in _______.
1 meter focal length = ____
1/2 meter focal length =_____
1/4 meter focal length = ______

A

Diopters
+1 diopter
+2 diopters
+4 diopters

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98
Q

For a concave lens, refractive power is measured to the ____________.

A

Rate light diverges

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99
Q

If a concave lens diverges light rays as much as a +10 diopter lens converges them, the refractive power is _______ diopters

A

-10 diopters

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100
Q

What is the pathway of light through the interfaces of the eye?

A

Air -> cornea -> aqueous humor -> lens -> vitreous humor

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101
Q

The greatest change in refractive power is the transition from ______ to _______

A

Air to the cornea

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102
Q

______ is the strongest lens of the eye

A

The cornea

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103
Q

the refractive power of the eye is ___ diopters in an unaccommodated and distant light source

A

+59

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104
Q

Describe accommodation of the eye

A

The lens changes its shape and therefore its refractive power to focus the image

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105
Q

For near vision, the circular muscle ______ or ________ to focus.

A

contracts or Accommodates

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106
Q

The circular muscle _______ for far vision

A

Relaxes

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107
Q

________ controls the circular muscle that is involved in accommodation of the eye

A

Oculomotor nerve - parasympathetic

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108
Q

______ functions to change the amount of light that enters the eye. Ranges from _____ to ______mm

A

Iris

1.5 - 8mm

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109
Q

In regards to the Iris more light enters at ________ and less light enters during the _____. (Night or day)

A

Night

Day

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110
Q

Does a smaller or larger pupil give greater depth of focus?

A

Smaller pupil has greater depth of focus

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111
Q

The depth of focus is determined by what?

A

The size of the pupil

The smaller the pupil, the greater depth of focus

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112
Q

______ is a refractive disorder of the eye in which parallel light from a distant course is in focus and lens accommodation is normal.
Normal vision.

A

Emmetropia

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113
Q

_________ is a refractive disorder of the eye in which lens becomes less elastic and won’t round up during ciliary muscle contraction

A

Presbyopia

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114
Q

_________ is AKA farsightedness

A

Hyperopia

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115
Q

In ________ the focal point is behind the retina so the lens is used to focus for FAR vision; not enough left to focus for near vision.

A

Hyperopia (farsightedness)

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116
Q

__________ is AKA nearsightedness

A

Myopia

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117
Q

In _______ the relaxed eye the focal point is ahead f the retina. Cannot focus distant objects

A

Myopia (nearsightedness)

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118
Q

_________ is irregular shape of the cornea

A

Astigmatism

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119
Q

________ are cloudy areas in the lens caused by denatured eye proteins

A

Cataracts

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120
Q

Describe the differences between near and far sightedness with normal vision.

A

Normal vision: occurs when light is directly focuses on the retina rather than infront or behind it

Near sightedness: visual image is focused infront of the retina

Farsightedness: visual image is focused behind the retina

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121
Q

_______ is normal vision

_________ is myopia

A

20/20

20/100

122
Q

What doe 20/100 visual acuity mean?

A

What a normal person can see at 100 feet, the nearsighted person can see at 20 feet

The bigger the bottom number the worse the vision

123
Q

_______ is the ability to perceive relative distance of objects in the visual field

A

Depth perception

124
Q

What are the 4 mechanisms of depth perception?

A

Sizes of images of known objects
Moving parallax
Stereopsis
Occlusion

125
Q

How can size of known objects effect depth perception?

A

This wold get can be used to judge the distance away a person is relative to the size the image appears on the retina

126
Q

When a person is moving foreground objects appear to be passing by faster than distant objects is the ____________ mechanism of depth perception

A

Moving parallax

127
Q

_______ is AKA binocular vision. Light from distant objects project to more central points in the retina. Light from near courses project more laterally

A

Stereopsis of depth perception

128
Q

When is binocular vision most useful?

A

In closer ranges

129
Q

______ is the points in space whose images fall on corresponding points on the two retinas so that it appears as a single object

A

Horopter

130
Q

Binocular disparity appears as ______

A

Double vision

131
Q

Points neared than the Horopter have _______ disparity

A

Crossed

132
Q

Points father than horopter have _______ disparity

A

Uncrossed

133
Q

Binocular disparity can be ______ or _______

A

Crossed or uncrossed

134
Q

In depth perception, _______ is used as a cue to depth to where if something is infront of another you obscure the vision to the object that is behind to focus on the thing infront.

A

Occlusion

135
Q

________ is liquid formed by the ciliary processes of the eye

A

Aqueous humor

136
Q

_________ circulates between the cornea and lens and is removed through the Canal of Schlemm

A

Aqueous humor

137
Q

Aqueous humor circulates between the ______ and the _______ and is removed through the _________.

A

Circulates- between cornea and lens

Removed- canal of schlemm (scleral venous sinus)

138
Q

The aqueous humor is removed through the canal of schlemm which empties into the _______ veins

A

Extraocular veins

139
Q

______ exerts a pressure inside the eye to keep it distended (about 15mmHg)

A

Aqueous humor

140
Q

________ occurs due to increased intraocular pressure due to aqueous humor outflow problems such as debris clogging canal of schlemm

A

Glaucoma

141
Q

In glaucoma, pressure can be measured by ______. The pressure can compress _______ leading to permanent ______

A

Tonometry
Retina
Blindness

142
Q

The main symptom of glaucoma is _________

A

Gradual loss of vision

143
Q

What is chronic open angle glaucoma?

A

Loss of peripheral field vision happens first

144
Q

What are some indications of acute angle glaucoma?

A 
Sudden ocular pain and decreased vision 
Seeing halos around light 
Red eye 
Very high intraocular pressure 
Nausea and vomiting 
Fixed , mid-dilated pupil (oval pupil in some cases)
145
Q

The light must pass through _______ to be detected by photoreceptors in the retina

A

Most of the retinal layers

146
Q

The retinal layer arrangement causes _________ of visual acuity (loss or gain)

A

Some loss of visual acuity

147
Q

_______ is where the ganglion cells converge to form the optic nerve

A

Blind spot

148
Q

______ is the area of sharpest vision

A

Central fovea

149
Q

What makes up the photoreceptor layers of the central fovea?

A

Almost all cones

150
Q

In the central fovea, the Superficial layers of the retina are _______ to improve visual acuity of that area

A

Pushed aside

The retinal layers function to cause some loss of visual acuity which is why in the area of greatest visual acuity the retinal layers would be pushed aside

151
Q

The ______ layer of the retina contains melanin and stores vitamin A

A

Pigment layer

152
Q

What is the function of the melanin in the epithelium in the pigment layer?

A

Absorbs light so that it wont scatter within the eyeball

153
Q

Albinos lack the _______ part of the pigment layer and therefore have _______ (better or poorer) visual acuity

A

Pigment (melanin)

Poorer visual acuity

154
Q

What are the layers of the retina? External to internal

A 
External limiting membrane
Pigment epithelium 
Photoreceptor layer 
Outernuclear layer 
Outerplexiform nucleus 
Inner nuclear layer 
Inner plexiform layer
Ganglion cell layer 
Nerve fiber layer
Inner limiting membrane
155
Q

What are the upper and lower borders of the retinal layers?

A

Upper- external limiting membrane

Lower - internal limiting membrane

156
Q

What are the 3 layers of the photoreceptive cells (rods and cones)?

A

Outer segment
Inner segment
Synaptic endings

157
Q

The _____ segment is light sensitive
The ______ segment is composed of the cytoplasm and nucleus
The synaptic endings synapse with _____ and _____

All are components of the photoreceptive cells

A

Outer segment- light sensitive
Inner segment - cytoplasm and nucleus
Synaptic endings - synapse with bipolar and horizontal cells

158
Q

Outer segments of photoreceptors contain membrane shelves that contain either ______ and ______

A 
Rhodopsin (rods)
Color pigments (cones)
159
Q

Rhodopsin is inactive, what is the active form of rhodopsin?

A

Metarhodopsin II

160
Q

______ and ______ can be recycled to form rhodopsin

A

Scotopsin and 11-cis retinal

161
Q

Metarhodopsin II ( active rhodopsin) breaks into ______ and _______

A

Scotopsin and all trans-retinal

162
Q

All trans retinal can be converted into ________ which is AKA vitamin A

A

All-trans retinol

163
Q

________ is activated rhodopsin

A

Metarhodopsin II

164
Q

What is the function of metarhodopsin II?

A

Excites the rods

165
Q

What is the role of vitamin A in rhodopsin activation?

A

Needed to supply eye with retinal as needed;

Excess is stored in the pigment epithelium

166
Q

In reconstituting rhodopsin, all trans retinal is converted to _______ and recombined with _____

A

11-cis retinal ; scotopsin

167
Q

What is the result of vitamin A deficiency

A

Night blindness

Main cause of blindness world wide

168
Q

Rods use ______, cones use _____

A

Rods - scotopsin

Cones- photopsins ( color opsins)

169
Q

What are the 3 types of color opsins (photopsins)?

A

Blue-sensitive
Green-sensitive
Red sensitive

170
Q

T/F: rod receptor potential is hyperpolarizing, not depolarizing

A

True

171
Q

In the excitation of rods:
In the DARK state, _____ cGMP levels keep Na+ channels _______ making a RMP of -40mV
In the LIGHT state, _______ leads to hydrolysis of cGMP making Na+ channels ______

A

Dark state: high cGMP, Na channels open

Light state: activated rhodopsin leads to hydrolysis of cGMP; Na channels close

172
Q

Mechanism of excitation of rods (5 steps):

A 
Light activates rhodopsin 
Rhodopsin activates transducin 
Transducin activates phosphodiesterase 
Phosphodiesterase converts cGMP into GMP
Therefore less cGMP is available to keep cGMP gated Na channels open
173
Q

What type of channels are important in rhodopsin excitation?

A

cGMP-gated Na+ channels

174
Q

The cascade from rhodopsin activation by photons to the activation of phosphodiesterase is ______. Such that a single photon can lead to _______ in Na+ conductance

A

Amplify

Significant drop in Na+ conductance

175
Q

________ is the enzyme that inactivates the activated rhodopsin (metarhodopsin II) and the rest resets.

A

Rhodopsin kinase

176
Q

What are the peaks of wavelengths the 3 photopsins are sensitive to?

A

Blue - 445 nm
Green - 535 nm
Red - 570 nm

177
Q

The ______ portion of all visual pigments is the same

A

Retinal

178
Q

Is the mechanism for excitation of cones the same as rods?

A

Yes

179
Q

Are cones more or less sensitive to light than rods?

A

Less sensitive about 30-300 times

180
Q

How does the brain interpret colors?

A

Based on the degree to which cone or cones respond to a particular wavelength of light.
The proportion to which each is stimulated determines color perception

181
Q

What makes someone red-green color blind?

A

Absence of either green (deuteranope) or red cones (protanope)

182
Q

______ is a type of color blindness inherited as an X-linked trait.

A

Red-green colorblind

183
Q

_______ (______) is due to underrepresented blue cones it is rare and NOT X-linked

A

Blue weakness (tritanope)

184
Q

_______ is total color blindness

A

Monochromacy

185
Q

In rod monochromacy the retina has no _______

In cone monochromacy there is only ________ of the cones

A

Rod- retina has no cones

Cone- only has one of the 3 cones

186
Q

What is used to test for color blindness?

A

Ishihara test plates

187
Q

________ can see all colors
_________ reduced ability to see red
________ reduced ability to see green

A

Trichromacy
Protanopia
Deuteranopia

188
Q

What is the mechanism of light adaptation?

A

When in bright light for a while, muscle of the photopigments in the rods and cones would be reduced to retinal and opsins. Some retinal will be converted to vitamin A. Therefore sensitivity will be reduced.

189
Q

What is the mechanism of dark adaptation?

A

Retinal and opsin are re-converted to photopigments to increase sensitivity

190
Q

Compare rods vs cones in adaptation

A

Cones adapt faster

Rods have a broader range of sensitivities

191
Q

_________ synapse wiht bipolar cells and horizontal cells

A

Photoreceptors (rods and cones)

192
Q

_________ transmit horizontal signals from photoreceptors to bipolar cells

A

Horizontal cells

193
Q

_______ transmit signals vertically from photoreceptors and horizontal cells to the inner plexiform layer

A

Bipolar cells

194
Q

_______ cells transmit either directly from bipolar cells to ganglion cells or horizontally within the inner plexiform layer or to other _____ cells

A

Amacrine

Amacrine

195
Q

What three places do amacrine cells transmit their signals from?

A

1) directly from bipolar cells to ganglion cells
2) horizontally within the inner plexiform layer
3) to other amacrine cells

196
Q

______ transmit output signals from the retina to the optic nerve

A

Ganglion cells

197
Q

_________ cells are involved in retrograde signals that help control degree of contrast in the visual image

A

Interplexiform cells

198
Q

What is the order of neural circuitry of the retina in the fovea?

A

Cones -> bipolar cells -> ganglion cells

199
Q

In the fovea there is ______ convergence, ______ system for sharp color and _______ and ____ cells cause lateral inhibition

A

Little convergence
Fast system for sharp color
Also horizontal and amacrine cells cause lateral inhibition

200
Q

What is the neural circuitry in the peripheral retina?

A

Both rods and cones -> bipolar cells -> amacrine cells -> ganglion cells (some bypass amacrine)

201
Q

In the fovea and the peripheral retina ______ and ______ cells have lateral inhibition roles

A

Horizontal

Amacrine

202
Q

Retinal cells except _______ cells do not form action potentials

A

Ganglion cells

203
Q

What is the only cell in the retina that actually forms an AP?

A

Ganglion cell

204
Q

How do the retinal cells conduct signals to the deeper layers of the retina?

A

direct Electrical current

205
Q

Direct electrical current in the retina allows for ________ conduction instead of _________

A

Graded conduction instead of all or none conduction

206
Q

Photoreceptors have a _____ membrane potential

Bipolar cells have a _______ membrane potential

A

Hyperpolarizing

Depolarizing

207
Q

_______ cells connect laterally between rods, cones and bipolar cells

A

Horizontal cells

208
Q

Is the output of horizontal cells inhibitory or excitatory

A

Always inhibitory

209
Q

________ prevents lateral spread of light excitation on the retina visual field

A

Lateral inhibition through the horizontal cells

210
Q

What is essential for transmitting contrast borders in the visual image?

A

Lateral inhibition

211
Q

What are examples of amacrine cell functions of different types of amacrine cells

A

1) direct pathway for rod vision
2) responds rapidly to stimulus onset
3) responds rapidly to stimulus off set
4) responds to both onset and offset
5) group is directionally sensitive

212
Q

T/F: visual information is processed before the signals leave the eye

A

True

213
Q

There are many more rods and cones than ganglion cells, therefore there are a lot of __________ circuits within the retina

A

Convergence

214
Q

In the fovea there is _____ (more or less?) convergence than in the periphery

A

Less

215
Q

What features of the fovea improve acuity?

A

Much less convergence than in the periphery

Cones are slender to pack in more photoreceptors

216
Q

In the peripheral retina, the rods are ________ light sensitive and there is ______ convergence

A

Much more sensitive to light

More convergence

217
Q

What features of the peripheral retina improve dim light perception?

A

Rods are much more light sensitive

There is more convergence in rods

218
Q

Ganglion cell axons converge to form the ______ that leaves the eye at the ______

A

Optic nerve

Blind spot

219
Q

Ganglion cells produce _______ potentials while rods, cones and other retinal cells produce _________ types of potentials.

A

Ganglion cells - action potentials (AP)

Rods cones and other cells- electrotonic conduction

220
Q

What are the two ganglion cell populations?

A 
P cells (parvocellular)
M cells (magnocellular)
221
Q 
P cells have 
\_\_\_\_\_\_\_ receptive fields 
\_\_\_\_\_\_ impulse conduction
\_\_\_\_\_\_\_\_ responses to stimuli 
\_\_\_\_\_\_\_\_ to color stimulus
A

Smaller receptive fields
Slower impulse conduction
More sustained responses to stimuli
Sensitive to color stimulus

222
Q

M cells are more sensitive to contrast _______ and ______ stimuli

A

Contrast black and white stimuli

223
Q

The opthalmic artery gives rise to what 2 artery’s that supply the eye?

A

Central retinal artery

Posterior ciliary arteries

224
Q

What is the blood supply to the retina itself?

A

Central retinal artery

225
Q

the central retinal artery enters the _________ to enter the _______ of the eye then branches throughout the retina

A

Optic nerve

Blind spot

226
Q

What is the blood supply to the choroid coat and outer segments of the rods and cones?

A

Posterior ciliary arteries

227
Q

retinal detachment is when the neural retina occasionally detaches from the _______

A

Pigment epithelium

228
Q

What are 2 examples of causes of retinal detachment?

A

Injury

Pulling effect by defective vitreous humor fibers

229
Q

The direct visual pathway from the ganglion cells to the visual cortex is:
Ganglion cells form the _______
Optic nerves from both eyes converge on the _________. The fibers emerge from chiasm as the ________ which terminates in the _________

A

Optic nerve
Optic chiasm
Optic tract -> lateral geniculate nucleus of the thalamus

230
Q

In the visual pathway once the optic tract terminates in the lateral geniculate nucleus, second order fibers project ot the ________ via the ______

A

Occipital cortex via the geniculocalcarine tract (aka optic radiations)

231
Q

The primary visual cortex is in brodmanns area _____ in the gyri next to the _______ fissure

A

17

Calcarine fissure

232
Q

Optic nerves converge at the optic chiasm. There is a ______ retina that decussates and a _____ retina that does not

A

Nasal retina decussates

Temporal retina does not

233
Q

Lateral visual field projects to the ______ retina

Medial visual field projects to the _____ retina

A 
Medial retina (nasal retina)
Lateral retina (temporal retina)
234
Q

Nasal retina of ______ eye (R or L?) and the temporal retina of the _____ eye(R or L?) projects to the right visual cortex

A

Nasal retina of left eye
Temporal retina of the right eye
Project to the right visual cortex

235
Q

What are 3 older areas of the brain that the visual pathways also connect?

A 
Suprachiasmatic nucleus (hypothalamus)
Prerectal area (midbrain)
Superior colliculus
236
Q

_________ has visual fibers involved and functions to control circadian rhythms

A

Suprachiasmatic nucleus (hypothalamus)

237
Q

________ is a older area of the brain associated wiht the visual pathways in which reflex movements of the eyes and activating pupillary light reflex

A

Prerectal area (midbrain)

238
Q

_______ is an older area of the brain also associated with the visual pathway; it functions in controlling rapid directional movements of the two eyes

A

Superior colliculus

239
Q

the lateral geniculate nucleus has 2 layers of cells. Magnocellular and pravocellular. Layers 1 and 2 receive information from ________ cells.
Layers 3-6 receive information from _______cells

A

Layers 1 and 2: M cells (magnocellular)

Layers 3-6: P cells (parvocellular)

240
Q

Layers 1 and 2 of the lateral geniculate nucleus are magnocellular layers which have _______ vision and poor ________

A

Black and white vision

Poor point -point discrimination

241
Q

Layers 3-6 of the lateral geniculate nucleus are parvocellular layers which have _____ vision, good ________ and ______velocity

A

Color vision
Point-point discrimination is good
Slower velocity

242
Q

What are other names for the visual cortex?

A

V1 and striate cortex

243
Q

Where does the visual cortex lie?

A

Along the calcarine fissure of the medial occipital lobe

Brodmanns area 17

244
Q

In the primary visual cortex, signals from the ______ are most posterior and _______ is more anterior

A

Macula most posterior

Peripheral vision most anterior

245
Q

Where in the primary visual cortex does the upper retina project to? Lower retina?

A

Upper retina- gyrus superior to the calcarine fissure

Lower retina - goes lower to the lower gyrus

246
Q

What is another name for secondary visual cortex?

A

V2, visual association area

247
Q

Secondary visual cortex surrounds the ________. Brodmanns area _____

A

Primary area

18

248
Q

V1 (primary visual cortex has _________ layers

A

6

249
Q

________ fibers of the primary visual cortex mainly terminate in layer IV

A

Geniculocalcarine

250
Q

The M cells and P cells terminate in different subsections of layer ______ then signals are passed vertically to more superficial and deep layers.
layers I-III transmit ______ distances
Layers V-VI transmit ______ distances

A

IV
Short
Further

251
Q

________ columns processes a bit of visual information. Some columns form _________ which are primary areas for deciphering color

A

Vertical neuronal columns; color blobs

252
Q

T/F: signals from the two eyes remain separate until they reach the cortex for comparison

A

True

253
Q

Lateral retina of the left eye P ganglion cell -> _______ layer layers 3-5-> a particular visual column in the ______ visual cortex

A

Ipsilateral LGN

Left visual cortex

254
Q

Columns from the left and right eye in the cortex are ______ to each other and are compared there to check if the images are ________

A

Adjacent ; “in register”

255
Q

What is the basis of stereopsis and important to adjust the directional gaze so the eyes are focused not he object of interest?

A

Columns for the left and right in the cortex are adjacent to each other like stripes and are compared there to check if the images are in register

256
Q

Cortical visual analysis has a ______ and ______ pathway

A

Fast and slow

257
Q

The fast pathway for cortical visual analysis is for _______ and _______

A

Position and motion

258
Q

slower pathway of cortical visual analysis are for ______ and _____

A

Accuracy and color

259
Q

_______ pathway of ______ analyzes gross physical form of the scene and detects motion

A

Fast pathway of cortical visual analysis

260
Q

Fast pathway of cortical visuala nalysis mainly uses information from _______ ganglion cells (______, _____)

A

M ganglion cells (rapid signals, no color)

261
Q

After the fast pathway leaves V1 it goes to ________ cortex where it merges with signals from the somatic association area

A

V2 occipitoparietal cortex (secondary visual cortex)

262
Q

The slower pathway of cortical analysis is for ______ and _______

A

Accuracy and color

263
Q

________ analyses visual detail and color. Uses information from P ganglion cells as well as M

A

Slower pathway of visual cortical analysis

264
Q

After the slower pathway leaves the primary cortex it goes tot eh secondary visual cortex in the _______ and ______ areas of the ______ and _____ cortex

A

Inferior ventral and medial

Occipital and temporal

265
Q

Which pathway In cortical visual analysis is necessary for reading, seeing texture and detailed color?

A

Slower pathway of cortical visual analysis

266
Q

A blind spot is found ab out ______ degrees _______ to the central point of vision

A

15 degrees lateral

267
Q

What occurs when there is a lesion of the right optic nerve?

A

Total blindness of the right eye

268
Q

What occurs due to a lesion involving the right perichiasmal area?

A

Right nasal hemianopia

269
Q

What occurs due to a midline chiasm always lesion?

A

Bipolar (Bitemporal) hemianopia

270
Q

What occurs due to a lesion o pressure on the right optic tract?

A

Left homonymous hemianopia

271
Q

What occurs due to a lesion of the right occipital

A

Left homonymous hemianopia

272
Q

What eye muscles moves eyes sideways

A

Medial and lateral recti

273
Q

What muscles moves eyes up and down?

A

Superior and inferior recti

274
Q

What muscles rotate eyeballs to keep visual fields upright?

A

Superior and inferior oblique

275
Q

CN III innervates what eye muscles?
CN IV?
CN VI?

A

III - all other extraocular muscles
IV- superior oblique
VI- lateral rectus

276
Q

Medial longitudinal fasciculus (MLF) receives information from what 4 areas?

A 
Vestibular nuclei (equillibrium)
Lateral lemniscus (hearing)
Superior colliculus (visual)
Frontotectal tract (voluntary movements)
277
Q

What are the efferents of the medial longitudinal fasciculus?

A

CN III, IV, VI to control extraocular muscles

278
Q

_______ functions to coordinate head and eye movements in response to visual, auditory, balance and voluntary signals

A

Medial longitudinal fasciculus

279
Q

_______ is within the brain stem and links the vestibular nuclei with the nuclei supplying the extraocular muscles and coordination of the head and eye movements

A

MLF

280
Q

How is voluntary fixation controlled?

A

The premotor area in the frontal lobe

281
Q

How is involuntary fixation controlled?

A

Controlled by area in secondary visual cortex

282
Q

What si the difference between voluntary and involuntary fixation?

A

Voluntary - voluntarily setting your gaze

Involuntary- locks the gaze on the object.
Can only be unlocked by voluntary override or by closing eyes

283
Q

The eyes have a continuous tremor, to _______ and may drift its gaze.

A

To keep the visual stimulus fresh

284
Q

When an object drifts for the fovea as a result of these continuous tremors, the eyes reflexively move the object back (______)

A

Saccades

285
Q

The mechanism of involuntary fixation’s effect is mediated by the _________

A

Superior colliculus

Superior colliculus also causes you to turn your head toward a visual disturbance involuntary

286
Q

What are 2 examples of saccadic movement?

A

Optokinetic movements (when riding in a car, the eyes fix on successive objects then jump to the next)

Reading (eyes do not smoothly can from left to right when reading. Does a series fo saccades from one group of words to the next)

287
Q

________ is fixation on a moving object

A

Pursuit movement

288
Q

Fixation on a moving object is ______ (smooth or choppy)? The eyes get fixed on amoving object, then move with the object wot keep it in the _______

A

Smooth ; fovea

289
Q

In ________ of visual images, the two eyes must be aimed the correct direction in order for the points of the same image to land on both fovea. If not the image will not be ________

A

Fusion of visual images

Fused

290
Q

In ________ because the eyes are about 2 inches apart, images can never be completely fused. The closer an object is to the face the more interference there will be

A

Stereopsis

291
Q

What is the basis of binocular depth perception?

A

Stereopsis

292
Q

_________ is due to lack of fusion between the 2 eyes?

A

Strabismus

293
Q

_______ is Often due to some damage to one of the ocular CN‘s

A

Strabismus (lack of fusion between 2 eyes

294
Q

Strabismus may be due to cortical reasons as well when the brain ignores one eye due to _______

A

Prolonged issuers wiht poor fusion or focus (amblyopia or lazy eye)

295
Q

Explain the pupillary light reflex. And what are the 2 types?

A

Shining a light into one eye causes bilateral pupil constriction (sphincter of the iris)
Direct (same eye) consensual (opposite eye)

296
Q

The pupillary light reflex’s motor pathway is similar to cause _________

A

Lens focus (ciliary muscle)

297
Q

Interruption in Sympathetic innervation to iris is called _______

A

Horner’s syndrome

298
Q

Interruption of the sympathetic pathway to the head leads to ______, _______ and ______

A

Mitosis (pupil constriction)
Anhydrosis (lack of sweating on affected side)
Ptosis (droopy eyelid)

299
Q

What are 3 effects of accommodation (focusing for near objects)?

A

Constriction of the pupils
Increased lens thickness (ciliary muscle contraction)
Medial convergence of eyes

300
Q

What is the pathway of accommodation reflex?

A

Blurred retinal image-> retinal nervous elements -> optic nerve -> optic chiasma -> optic tract -> LGB (thalamus) -> optic radiation -> primary visual area (17); occipital lobe and association visual area (18 and 19)

Neurophysiology (4 decks)

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