Week 2 midterm 2 Flashcards Preview

ANSC 310 > Week 2 midterm 2 > Flashcards

Flashcards in Week 2 midterm 2 Deck (158)
Loading flashcards...
1

What is a reflex arc?

neural pathways for reflexes

2

What is the muscle spindle stretch reflex?

the reflex pathway in which muscle stretch initiates a contraction response

3

What are the 5 neural pathways of a reflex arc?

*stimulus*
1. sensor receptor
2. afferent neuron
3. integration center
4. efferent neuron
5. effector organ
*response*

4

Spinal reflexes require what?

require NO input from the brain

5

Cranial reflexes require what?

require input from the brain (integrated from within)

6

Innate reflexes

Genetically programmed in everyones body

7

Conditioned reflexes

learned reflexes - acquired through experience

8

Monosynaptic reflexes

Have 2 neurons - afferent and efferent (only somatic motor reflexes)

9

Somatic motor reflexes

Controls the effector - controls skeletal muscles (efferent)

10

Autonomic reflexes

Controls the effector - control smooth and cardiac muscle, glands and adipose tissue (efferent)

11

Polysynaptic reflexes

One or more interneurons between afferent and efferent neurons (all autonomic reflexes -- have 3 neurons)

12

What is the stretch reflex (aka knee-jerk reflex)

only known monosynpatic reflex
- receptor is a muscle spindle that detects lengthening of the muscle
- tapping the patellar tendon below the knee cap causes the quadriceps in the upper thigh to stretch which excites the muscle spindles, therefore generating AP's that travel to the spinal cord

13

What are muscle spindles

stretch receptors that send info to the spinal cord and brain about muscle length and changes in it

14

What are proprioceptors?

sensory receptors in the subcutaneous tissues that detect motion and position of the body through a stimulus produced within the body (in muscles and joints)

15

What do extrafusal muscle fibers do?

receptor for stretch and force -- most of the muscle and are the major force-generating structure (larger than intra)

16

What are intrafusal muscle fibers?

found within each muscle spindles, contain afferent receptors for stretch and contractile elements on the ends (smaller than extra)
- central region lacks myofibrils

17

What is the central region of an intrafusal muscle fiber composed of?

no myofibrils, wrapped with sensory nerve endings stimulated by stretch

18

What is muscle tone?

the amount of tension in muscles (even a little bit present at rest)

19

What do sensory neurons do? (X3)

- get activated by sensory input from the environment
- send AP's to the spinal cord
- continuously activate motor neurons keeping the muscle at a tone

20

What happens when spindles/muscles stretch?

- causes sensory fibers to fire more rapidly
- more AP generated
- creates a reflex contraction to prevent damage

21

What keeps muscle spindles alive?

gamma motor neurons

22

What keeps muscle spindles alive/tense/give them tone?

gamma motor neurons

23

What do alpha motor neurons do?

largest neurons in the spinal cord, innervate (provide nerves) extrafusal muscle fibers and are directly responsible for initiating their contraction

24

What are the 4 key things for a successful completion of a voluntary motor task

1. development of an idea to move
2. putting together a program of motor commands for the movement
3. executing the movement
4. constant feedback to ensure it was smooth and successful

25

What does the spinal cord do?

it integrates spinal reflexes and contains central pattern generators

26

What do the brainstem / cerebellum do?

control postural reflexes and hand / eye movements

27

What does the cerebral cortex and basal ganglia do?

they are responsible for voluntary movements

28

What does the thalamus do?

relays and modifies signals (manager) as they pass from the spinal cord, basal ganglia and cerebellum to the cerebral cortex

29

What do central pattern generators (CPG's) do?

maintain spontaneous repetitive activity
- neural circuits
- walking, swimming, breathing or chewing

30

Voluntary movement requires coordination between what 3 things?

1. cerebral cortex
2. cerebellum
3. basal ganglia

31

Voluntary movement requires coordination between what 3 parts of the body?

1. cerebral cortex
2. cerebellum
3. basal ganglia

32

Voluntary movement requires what 4 things?

1. knowledge of the bodys position
2. a decision to execute
3. a plan for execution
4. memory of that plan

33

Limbic system is related to what step of voluntary movement?

idea

34

Association areas are related to what step of voluntary movement?

idea

35

Supplementary motor area is related to what 2 steps of voluntary movement?

idea / program

36

Premotor area is related to what step of voluntary movement?

program

37

Primary motor cortex is related to what step of voluntary movement?

program

38

Pyramidal tract is related to what step of voluntary movement?

execution

39

Extrapyramidal tract is related to what step of voluntary movement?

execution

40

Motor neuron is related to what step of voluntary movement?

execution

41

Sensory systems are related to what step of voluntary movement?

feedback

42

Cerebellum is related to what step of voluntary movement?

feedback

43

Thalamus is related to what step of voluntary movement?

feedback

44

Basal nuclei are related to what step of voluntary movement?

feedback

45

Brainstem is related to what step of voluntary movement?

feedback

46

What does the pyramidal tract neuron do?

it controls distal extremities: hands, toes, fingers, etc (distal = further away than proximal)
- takes info from upper motor neurons in the cortex and direct lower motor neurons in the spinal cord (directly connected or indirectly connected with interneurons)
- one pathway
- voluntary movement

47

Why don't horses have very developed pyramidal tracts?

cause they don't have hands or toes

48

Where is the upper motor neuron and what does it do? How does it respond to signals?

- located in the spinal cord
- always excitatory
- receives signal from the upper motor neuron: fires an AP and muscle contracts
- receives no signal: nothing happens, muscle stays at rest

49

What do extrapyramidal tract neurons do and what kinda inputs do they have?

pathways outside pyramidal tracts
- support voluntary movement of proximal extremeties (closer to the body than distal)
- controls movement of the trunk, neck and legs
- involuntary movement
- indirect input only

50

What are the 3 pathways for extrapyramidal tracts and where do they go?

1. rubrospinal (red): midbrain to spinal cord
2. vestibulospinal: vestibular nuclei to spinal cord
3. reticulospinal: medualla oblongata to spinal cord

51

What does the body use for involuntary control over posture?

receives info from the eyes and ears (vestibular system)
- sensory receptors in the skin
- muscles and joints (proprioceptors)

52

What is the role of the cerebellum? (x4)

- compares actual to planned movements (regulation of motor coordination)
- stores programs for remembered motor activities
- informs the cortex to make corrections
- contributes to muscle tone

53

Do herbivores or omnivores/carnivores tend to sleep longer/more?

Carnivores/omnivores

54

What is the definition of sleep?

a reversible and normal suspension of consciousness
- active process: requires E

55

What are the most likely reasons for sleep?
- hypotheses why

- conserve E (best/most likely reason)
- allows the body to repair itself
- process memories
- lets brain rest/restore energies
- helps the immune system function
- clearing waste out of the cerebral spinal fluid (especially proteins)
- helps improve performance on tasks and tests

56

What is electroencephalography?

the electrical activity of the brain
- uses metal discs
- EEG

57

What are the 4 stages of sleep?

W: wake stage
REM: rapid eye movement
N1,N2,N3: slow wave or non REM

58

What is REM sleep (rapid eye movement) stage R?

- every 90 mins
- beta waves
- associated with dreaming
- most likely to wake up during
- eyes move and brain is active
- starts 90 mins after falling asleep and the phases of it get longer throughout the night
- characterized by waves with low amplitude and high frequency
- paralyzes skeletal muscles

59

What are stages N1 and N2 of non-REM?

- theta waves
- N1 = lightest stage of non-REM sleep
- N2 deeper than N1

60

What is N3 stage of non REM?

- slow wave / deep sleep
- delta waves
- most difficult to awaken
- high amp, low frequency (opposite to REM)
- adjust body position without command from the brain

61

Towards the end of sleeping, what stages do you spend in most?

REM and N1

62

What stages of sleep are you in at first?

N1 and N3

63

What controls circadian rhythm?

the hypothalamic biological clock

64

What does the biological clock do?

causes changes in the level of wakefulness in response to day/night cycles

65

What is the ascending reticular activating system (ARAS)?

part of the reticular formation that projects to the thalamus, hypothalamus, and forebrain; signals to the entire brain, most prominently in the cortex

66

What does the forebrain do in respects of sleep?

Induces non-REM sleep (N1,2,3)

67

What 3 groups of neurons are involved in sleep-wake cycles?

noradrenergic (norepinephrine), cholinergic (acetylcholine) and serotonergic (serotonin)

68

What drugs are high during wakefulness and low during sleep?

norepinephrine, serotonin and orexin

69

What drugs are high during wakefulness and REM but low during non-REM?

acetylcholine and dopamine

70

What are the 4 steps to falling asleep?

1. nerves from the eye signal the suprachiasmatic nucleus (SCN) that the light level is decreasing
2. SCN stimulates the ventrolateral preoptic nucleus
3. VPN decreases the activity of the reticular formation
4. decreased activity causes the thalamus to disconnect from the cerebral cortex. therefore decreasing the level of conciousness

71

What is the suprachiasmatic nucleus (SCN)?

it recieves signals from the eye that light is decreasing and stimulates the ventrolateral preoptic nucleus

72

What are orexins and what do they do?

a neurotransmitter that increases before wakening and maintains a state of wakefulness
- stimulates reticular formation which in turn stimulates the thalamus to send an external sensory stimuli to the cerebral cortex

73

What triggers arousal?

orexin, and the activation of cholinergic and noradrenergic pathways

74

What are some things that sleep loss can cause?

- imbalance in temperature
- weight loss
- weakened immune system
- decrease in cognitive abilities
- hallucinations (humans)
- death

75

During infection, what stage of sleep is increased and decreased?

increased: N3
decreased: REM

76

What microbial components mimic the sleep effect?

lipopolysaccharide (LPS) and muramyl peptides

77

What interleukins can cause an increase in non-REM sleep?

increases in the intracverebral or plasma levels of the TNF or IL1

78

What are sensory receptors and how do they work?

they are specialized nerve endings that separate cells that detect a sensory stimulus or a specific form of energy

79

What are visceral afferents?

receptors that gather info from the visceral organs (heart, lungs, liver, pancreas, intestines, etc.)

80

What is the afferent branch?

a branch of the peripheral nervous system that carries info from the periphery to the CNS

81

What 2 sensory systems allow us to perceive the external environment?

1. somatosensory system
2. special senses

82

What does the somatosensory system do?

a sensory network that monitors the surface of the body and its movements

83

What are the 5 special senses

1. vision
2. hearing
3. balance/equilibrium
4. taste
5. smell
smell = neurons // rest = nonneural (synapse onto sensory neurons)

84

What are the 3 receptors and which have myelin

pain (no myelin)
touch (myelin)
ear hair (myelin)

85

What is the pacinian copuscle?

a touch receptor that detects transient pressure and higher frequency vibrations

86

Where are free nerve endings found?

in the skin and other tissues

87

What are chemoreceptors?

chemical sensors in the brain and blood vessels that identify chemical ligands that bind to it (O2, H, glucose... etc.)

88

What are mechanoreceptors?

sensory receptors responsible for sensing mechanical E due to distortion in body tissues such as pressure, cell stretch, vibration, acceleration and sound

89

What are baroreceptors?

sensory receptors that sense pressure changes

90

What are osmoreceptors?

sensory receptors that sense cell stretch

91

What are thermoreceptors?

sensory receptors that respond to varying degrees of heat (cold/hot)

92

What are photoreceptors?

sensory receptors that respond to photons of light (for vision -- detect light waves)

93

What is transduction?

the process of conversion of the stimulus energy into electrical energy or graded potentials (transfer of E from one form into another)

94

What is modality?

the E form of a stimulus (light/sound waves, pressure, temp, chemicals, etc) -- receptors specific to one type

95

What is an adequate stimulus?

the modality to which a receptor is most sensitive, and therefore best responds to

96

What causes graded potentials?

the opening and closing of ion channels (if greater than threshold, triggers an AP) -- increased stimulus increases the amplitude of a graded potential

97

What is adaptation?

a decrease in the amplitude of a receptor potential over time in presence of a constant stimulus
- decrease in the frequency of the AP
- decreases perception of the stimulus

98

How do most receptors respond to a stimulus?

some continue to respond for the full time its applied but MOST adapt to it and their response declines with time

99

Why do we get used to scents?

because olfactory receptors are rapid adapting receptors

100

What is the first order neuron?

the afferent neuron that transmits info from the periphery to the CNS

101

What are second order neurons?

interneurons that transmit the info to the thalamus

102

Where is the visual cortex located?

in the occipital and temporal lobes

103

Where is the gustatory cortex located and what does it do?

an area of the brain that receives and interprets tastes from the tongue -- located partly on the frontal lobe

104

What is the somatosensory cortex and where is it?

an area at the front of the parietal lobe that registers and processes body touch and movement sensations

105

What is the vestibular cortex and where is it located

posterior part of the insula and adjacent parietal cortex -- is responsible for conscious awareness of balance (head position in space)

106

Where is the olfactory cortex and what does it do?

located on the inferior surface of the frontal lobe -- detects smell

107

What is the auditory cortex and where is it located?

temporal lobe -- responsible for processing sound info

108

What do third order neurons do?

synapses form between them and second order neurons in the thalamus and they transmit info to the cerebral cortex

109

What is stimulus intensity coded by?

frequency (stronger stimulus results in a larger receptor potential) and population coding (stronger stimulus activates/recruits a greater number of receptors)

110

What is the definition of vision?

the process through which light reflected from object in our environment is translated into a mental image

111

What do photoreceptors do?

transduce light energy into an electrical signal in the retina

112

What do neural pathways in the retina do?

process electrical signals into visual images

113

What is the eye

a fluid filled organ

114

What is the outermost layer of the eye composed of and what does it do?

- sclera and cornea
connective tough tissue (white in colour)

115

What is the middle layer of the eye composed of and what does it do?

- choroid
gives nutrients for retina

116

What is the innermost layer of the eye composed of and what does it do?

- retina (photoreceptors -- rods and cones)
perceives light

117

How does blood enter and leave the eye?

enters: arteries
leaves: veins

118

What does the lens do?

takes light and focuses it into the retina

119

What does the pupil do?

regulates the amount of light that enters the eye

120

What does the iris do?

2 smooth muscles that regulate the diameter of pupil and regulates amount of light that enters the eye (pigment that gives the eye its colour)

121

What does the cornea do?

connective transparent tissue -- allows light to enter the eye

122

What do the zonular fibers/cilary body?

muscles that connect ligaments to the lens and change the size/focus of lens into the retina

123

What is the sclera?

An outside connective tissue

124

What is the fovea?

the region of sharpest vision (all cones)

125

What do zonules do?

they attach the lens to the ciliary muscle

126

What does the canal of schlemm do?

takes aqueous humour (fluid) and removes it

127

What causes glaucoma?

when liquid accumulates and the pressure damages the chamber (damage to the optic nerve)

128

What is the choroid?

it has blood vessels that nourish the retina

129

What maintains the shape of the eye?

vitreous chamber

130

What is the range of visible light?

380-750nm

131

How does wavelength relate to energy?

opposites: increase wavelength, decrease E (vv)

132

What can a cat see?

blurry during the day and sharp at night -- can't see red and green

133

What can a bird see?

red, green, blue and UV

134

What can a cephalopod see?

completely colour blind - shades of gray

135

What can a snake see?

low res during the day and good night vision - can see infrared

136

What is the inner circular muscle?

constrictor

137

What is the outer radial muscle?

dilator

138

What kind of light do animals and humans perceive?

reflected and emitted light

139

What is refraction of light?

the bending of light, when its speed differs in different mediums (ex. straw in water)

140

What does the retina do?

at the back of the eye, receives light that the lens has focused, converts the light into neural signals and sends them to the brain for visual recognition (eye computer signal)
- composed of neural tissue

141

What is the tapetum lucidum?

an iridescent layer found in nocturnal animals for maximizing vision under low intensity light; reflects visible light back through the retina, increasing light available to photoreceptors

142

What does the outer layer of the retina contain?

rods and cones (photoreceptors) -- communicate with bipolar cells

143

What does the middle layer of the retina contain?

bipolar cells (communicate with ganglion cells), amacrine cells and horizontal cells
(a and h cells provide lateral modulation)

144

What does the inner layer of the retina contain?

ganglion cells (axons form the optic nerve) -- first cell in the pathway to generate APs

145

What is the optic nerve?

bundle of nerve fibers that transmits sensory info for vision in the form of electrical impulses from the eye to the brain

146

What are rods? and what kinda/how many opsins

responsible for night vision (black and white), more plentiful in the retina, mostly in the periphery of the retina, high degree of convergence with bipolar cells
- shorter than cones
- 1 type of opsin (rhodopsin)

147

What are cones? and what kinda/how many opsins

responsible for colour and day vision, less plentiful in the retina, mostly in the fovea, low degree of convergence with bipolar cells
- longer than rod and more slender
- 3 types of opsin

148

Which vitamin greatly affects vision?

Vitamin A

149

Red opsin

L - responds to 560 (long wave)

150

Green opsin

M - responds to 530 (medium wave)

151

Blue opsin

S - responds to 420 (short wave)

152

What is transducin

the G-protein that couples rhodopsin to the enzyme phosphodiesterase in rod photoreceptors

153

How is colour perceived?

through cone comparison

154

How is glutamate used in convergence?

it is the transmitter released from rods and cones that communicates with bipolar neurons

155

What is melanopsin?

located in ganglion cells -- activated by light it sends signals to the SCN/hypothalamus (regulating circadian rhythm)

156

Where is binocular/monocular vision located?

binocular: directly in front
monocular: periphery
- animals with eyes on the sides of their heads have much more monocular vision than those who are in front

157

What is the opponent process theory?

cones can detect the presence of a colour because they inhibit the other colour

158

What is the trichromatic theory?

that each opsin / cone responds best to its own colour