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physiology 215 > module 1 > Flashcards

module 1 Flashcards

1
Q

what are the steps in exocytosis ?

A

1) secretory vesicle formation
2)budding of the Golgi
3) uncoating
4)docking at the plasma membrane
exocytosis happens

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2
Q

why are intra cellular and extra cellular environments are different ?

A

difference in ion concentrations which creates an electrical charge , and creates a membrane potential

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3
Q

anion

A

negative charge

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4
Q

cation

A

positive charge

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5
Q

what is ohms law ?

A

The relationship between membrane potential and ionic currents V=I*R

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6
Q

ion channels

A

large transmembrane proteins that open up to allow ions to enter or exit the cell , down their concentration gradient

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7
Q

voltage gated

A

open and close in response to changes in membrane potential

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8
Q

chemically gated

A

open with a specific chemical messenger( found in dendrites )

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9
Q

mechanically gated

A

open in response to mechanical deformations such as stretch

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10
Q

thermally gated

A

response to changes in temperature, present in specialzed neurons, act as temperature detectors

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11
Q

step 1: voltage gated channels

A

ion channels are closed , ions cannot freely move across the membrane , membrane has high resistance (R), and Ion movement is low (I).

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12
Q

step 2: voltage gated channels

A

If membrane potential changes to a voltage that causes the voltage sensor to open, the channels pores will decrease the membrane resistance to ion movement (becomes smaller )and the current will increase( I) or V?

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13
Q

step 3: voltage gated channels

A

at any given voltage, when resistance increases , current decreases
and when resistance decrease, current will increase

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14
Q

Concentration gradient

A

ions want to move down concentration gradient ( diffusions from high concentration to low concentration

ICF pushes potassium out of the cell into extra cellular fluid

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15
Q

electrical gradient

A

inside the cell is more negative due to the presence of non permeable anions.. This negative charge creates an inward electrical gradient or driving force that tries to prevent positively changed K from leaving the cell

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16
Q

the right and left hemisphere is connected by what ?

A

corpus callosum

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17
Q

the cerebral cortex is made up of?

A

grey matter

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18
Q

function of occipital lobe

A

initial process of vision

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19
Q

function of temporal lobe

A

vision and hearing

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20
Q

function of frontal lobe

A

voluntary motor activity, speech and elaboration of thought

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21
Q

parietal lobe function ?

A

responsible for receiving and processing sensory input

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22
Q

hyper polarization

A

magnitude of polarization moves even more negative than the resting membrane potential

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23
Q

graded potentials

A

local changes in membrane potential that are used for short distance signalling ( different than action potentials)

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24
Q

spread of depolarization

A

charge movement travels along membrane not across

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25
Q

action potentials

A

caused by triggering event or stimulus that results in a localized depolarization. It will conduct or propagate throughout the entire membrane and doesn’t lose its strength

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26
Q

when the membrane is depolarized, there is a rapid influx of ?

A

Na+ enters the cell to cause depolarization

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27
Q

input zone

A

part of neutron where the the incoming signals are received contains the dendrites and cell body

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28
Q

the trigger zone

A

part where the action potential is initiated contains the axon hillock( where the axon leaves the cells body)

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29
Q

Conduct zone

A

part of the neuron where the action potential is initiated contains the axon

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30
Q

output zone

A

part of neuron that releases chemical messengers contains axon terminals

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31
Q

dendrites

A

numerous projections from the cell body that receives electrical chemical

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32
Q

axon

A

extension that conducts the action potential away from the cell body

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33
Q

conduction

A

the result of an action potential down the axon is initiated , triggering a new action potential in an adjacent area

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34
Q

explain the transmission down the axon

A

1) action potential is triggered at the axon hillock

2) causes inside of membrane to become more positive , and causes adjacent areas from resting to threshold potential

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35
Q

refractory period

A

caused by the sodium channels remaining inactive after depolarization , which prevents the action potential going in the opposite direction

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36
Q

why can a refractory period be absolute or relative ?

A

absolute : under no circumstances can an action potential be triggered
relative : if triggering stimulus is strong enough, an action potential may be triggered

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37
Q

what does a strong signal mean ?

A

the firing rate of the action potential, not meaning that it is stronger signal

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38
Q

Mylein

A

formed by specialized Schwann cells and oligodendrocytes in the PNS and nerves leaving the spinal cord
Lipid rich regions that provide extra insulation to maintain the Current

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39
Q

describe the Nodes of Ranvier

A

regions where there is exposed fibre , action potential can be formulated here due to exposure to extra cellular fluid
dense area of Na + channels

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40
Q

saltatory conduction

A

in myelinated fibres the wave of excitation moves from one node of ranvier to the next which allows impulses to move faster

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41
Q

what are synapses

A

neuron to neuron junctions , the junction between a presynaptic neuron and a post synaptic neuron which includes the synaptic cleft between the 2

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42
Q

Neurontransmitters

A

chemicals released into the synaptic cleft which activate ion channels on the post synaptic neurons membrane

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43
Q

synaptic cleft

A

area of extracellular fluid between pre and post synaptic neurons

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44
Q

what are the mechanisms of synaptic transmission

A

1) electrical action potential reaches the axon terminal in the pre synaptic neuron

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45
Q

receptor adaptation

A

receptors have the ability to regulate their response , meaning a stimulus of same intensity does not always bring about the same magnitude of potential

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46
Q

tonic receptors

A

generally slower and do not adapt at all, important in situations where near constant signal from stimulus is necessary

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47
Q

phasic receptors

A

rapidly adapting, upon initiation of stimulus
ex) mechanoreceptors known as pacinian corpuscles
watch example , realize the watch is there and then sensation fades

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48
Q

Nociception or nocireceptors

A

also known as pain: alerts the CNS. can take the form of internal and external events , nocirecptors are found throughout the body
Pain receptors do no adapt

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49
Q

Mechanical nocireceptors

A

respond to physical damage such as cutting or crushing

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50
Q

thermal nocireceptors

A

respond to temperature

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51
Q

chemical nocireceptors

A

respond to noxious chemicals which are both external and internal to the body

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52
Q

Fast Pain fibres

A

A delta , covered in mylein and are wider in diameter they are responsible for responding to temp nd chemical and mechanical stimuli.( Sensation of quick intense pain, sharp, stabbing )

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53
Q

Slow Pain fibres

A

C fibres , not myelinated and respond to temp, chemical and mechanical stimuli. They can activate.

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54
Q

Slow pain fibres can activate what ?

A

Polymodal fibres ( receptors that respond to multiple stimuli. Associated with the burning, aching or throbbing feeling with pain

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55
Q

Bradykinin

A

chemical that is activated and associated with slow pain pathway. Released from damaged cells and stimulates nocireceptors . explains long lasting pain.

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56
Q

How does the brain process pain ?

A

1) action potential reaches the end of an afferent pain fibre axon, triggers the realize of neurotransmitters ( Substance P and Glutamate ). Both which help activate the ascending pathways and transmit signals for higher processing

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57
Q

Reticular formation role in processing pain ?

A

Increases the level of alertness and awareness of a painful stimulus

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58
Q

Hypothalamus/ limbic system

A

receives information from the thalamus and the reticular formation and allows for behavioural and emotional responses to the pain stimuli

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59
Q

Thalamus

A

processing here allows for the perception of pain

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60
Q

Cortex

A

Cortical Somatosensory processing localizes the pain to discrete body region

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61
Q

Glutamate

A

Released by nocireceptive afferent nerve fibres to activate post synaptic glutamate receptors on neutrons of the dorsal horn and spinal cord

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62
Q

What are the 2 actions of glutamate ?

A

Activates either AMPA or NMDA receptors

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63
Q

What happens when AMPA receptors are activated ?

A

leads to permeability changes that can generate action potentials in the dorsal horn neuron and send the signal to higher brain regions

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64
Q

what happens when NMDA receptors are activated ?-

A

Only happens when certain level of depolarization has taken place with AMPA receptor. Allow calcium to enter neuron, which leads to the activation of a second messenger pathway that results in neuron being more excitable than normal( why injured areas are more sensitive to stimuli

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65
Q

How is a pain signal stopped ?

A

through the built in endogenous analgesic system which allows for the release of endogenous opioids ( substances released from the body hat have pain killing effects and suppresses the neurotransmitters being released from the afferent pain fibres

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66
Q

Exogenous opioids

A

substances that have pin killing effect but are not produced int he body

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67
Q

explain what would happen if you stepped on a piece of lego

A

1) pain would be fist percieved in the delta A fibres, which would then travel to the end of the fibre, glutamate would be released
2) glutamate would allow for the activation of AMPA receptors at the dorsal horn ,
3) the signal would then travel to the reticular formation
4) then to the thalamus to perceive pain and to the cortex to localize the pain to the foot .
5) the hypothalamus would allow for an emotional or behavioural response

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68
Q

Pupillary constriction

A

caused by the parasympathetic stimulation. One set of muscles is organized in a circular fashion and constrict to make the pupil smaller

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69
Q

Pupillary dilation

A

caused by parasympathetic stimulation. set of muscles is organized radially ( from the pupil to edge of iris ). Contract to allow more light in

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70
Q

what happens when light passes through a transparent media with density different from air ?

A

1) the wavelength decreases

2) unless it enters the media perpendicularly its direction will change (known as refraction )

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71
Q

refraction

A

the bending of light when it passes one medium to another

72
Q

cornea

A

contributes the most to the refractive abilities because foe the density difference at the air / cornea boundary
Uneven surface of cornea= astigmatism

73
Q

Lens

A

convex structure located behind the pupil that is able to focus light rays onto the retina . The lens is adjustable

74
Q

Accommodation

A

eyes ability to adjust the lens to maintain focus on something.

75
Q

what muscles control accommodation ?

A

The ciliary muscle and the suspensory ligaments . When muscle is relaxed , the ligaments pull the lens flatter, less convex shape
When muscle contracts, it reduces the tension of the ligaments and the lens becomes more convex

76
Q

Ciliary muscle contraction is controlled by ?

A

the ANS with eh sympathetic stimulation causing relaxation and parasympathetic stimulation causing contraction

77
Q

When the light source is closer what happens ?

A

Light rays are diverging when the are entering the eye so a stronger more convex( greater ability to bend the light ) lens is needed to bring the light to focus

78
Q

what happens when a light source is farther away ?

A

light rays are parallel to one another ( less convex lens needed ).

79
Q

retinal visual pathway

A

extends from the photoreceptor cells( cones and rods) to the bipolar cells and then to the ganglion cells
( direction of light moves in the opposite direction of the visual processing )

80
Q

rods and cones

A

cones for colour, rods for vision in low lighting

81
Q

Bipolar cells

A

involved in the transmission of signals from rods and cones to the ganglion cells

82
Q

Ganglion cells

A

The neutrons located at the inner surface of the retina its axons make up the optic nerve

83
Q

location of blind spot ?

A

optic disc ( where the ganglion cells bundle together to form the optic nerve.

84
Q

what is the visual pathway?

A

transmitted to the visual pathway to the thalamus and relays information to each different area of the cortex( color, form depth movement. Vision takes up 30 % of the cortex processing

85
Q

what side of the brain processes the the right visual field ?

A

The left side

86
Q

what would happen the left optic nerve was cut ?

A

lose vision in both the left and right side of left eye

87
Q

what would happen if the optic chiasm was cut ?

A

loss of vision in the right visual field in right eye and the left visual field in left eye

88
Q

cut of left optic tract ?

A

loss of right field of vision in both eyes

89
Q

what is a sound wave ?

A

a vibration of air that travel outward from the source . Transfer energy from molecule to molecule ( lose energy much faster

90
Q

Pitch ( tone )

A

determined by the frequencuy of vibrations . the greater the frequency the higher the pitch

91
Q

Intensity ( loudness )

A

depends of the amplitude of the sounds waves and the greater the amplitude, the louder the sounds

92
Q

Timbre ( quality of sound)

A

overtones that are superimposed on the pitch. Allows one to locate the source of the sound as each sound has different overtones

93
Q

external ears composed of ?

A

The pinna , the tympanic membrane and the ear canal. Its job is to channel sound waves to the middle ear

94
Q

Pinna

A

are essential for the location of sound and collects sound waves

95
Q

ear canal

A

sends the waves to the tympanic membrane. Contains hairs and earwax to guide against bacteria ( make the environment more acidic ).

96
Q

Tympanic membrane

A

vibrates when sound waves hit it. Stretches across entrance to middle ear. Air pressure must be similar to atmospheric pressure for it to work efficiently.

97
Q

Middle ear

A

composed of the malleus incus and stapes. transfer the vibrations and amplify the sound to the inner ear fluid. via the oval window

98
Q

Inner ear

A

Cochlea, Organ of Corti, inner hair cells and outer hair cells

99
Q

what happens at the oval window

A

sound waves get converted to mechanical energy and then past on into the inner ear

100
Q

The Cochlea

A

Fluid filled , responsible for the perception of hearing . Important in the ability to determine pitch

101
Q

organ of Corti

A

located inside the cochlea , supposed by the basilar membrane and contains hair cells. known as the sense organ

102
Q

Inner hair cells

A

transform the cochlear fluid vibrations into action potentials , and propagates auditory messages to the cortex

103
Q

Outer hair cells

A

Do not transmit sound signals to the brain. Instead these hair cells function to modify the electrical signalling of the inner hair cells. They enhance the response of the inner hair cells making them more sensitive to sound intensity and pitch

104
Q

how is pitch determined ?

A

depends on the shape of the basilar membrane. Rnage of pitch is heard in different parts of the cohlea

105
Q

Higher pitches ( 2000hz) are detected at which end of the cochlea? and Lower pitches ?

A

At the narrow end ( higher ) and lower pitches ( and the wider end

106
Q

Hair cells send what type of signals ?

A

auditory signals are picked up from the hair cells and then sent to the auditory nerve. and pass through brainstem( alertness and arousal and then to the thalamus for higher processing

107
Q

Vestibular apparatus

A

In the inner ear, contains fluid ad hair cells that are able to detect changes in movement in the fluid. contains the information needed to maintain equilibrium, balance and coordination by detecting changes in head movement

108
Q

how does the vestibular system help maintain equilibrium ( pathway )

A

signals of the vestibular system are sent to the vestibular nuclei in the brainstem and then to the cerebellum

109
Q

The 3 functions of the vestibular system are :

A
  1. Maintain balance and posture
  2. allow the eyes to remain fixed when turning the head
  3. Perceive motion with orientation
110
Q

Chemo receptors

A

both taste and smell rly on these, generate electrical signals after binding to a specific chemical

111
Q

taste

A

known as Gustation, sensation produced when. substance reacts with a taste receptor in the oral cavity

112
Q

Tongue, oral cavity and throat

A

location of chemo receptor s

113
Q

Taste buds

A

the tongue is covered with bumps called papillae. Clusters of nerve ending on the tongue and lining of the mouth and each one contains about 50 taste receptor cells. limited life span of about 10 days

114
Q

Taste receptor cells

A

when a tastent ( any chemical that stimulates the sensory cell in a taste bud ) binds to receptors. Ion channels create depolarizing potential which can imitate action potential

115
Q

How is taste experienced in the brain ?

A

afferent neurons send signals to the brainstem and thalamus before going to the cortical gustatory area in parental lobe

116
Q

salty taste

A

cells are stimulated by salts , these cells have special NA = Channels that allow for direct entry into the cell

117
Q

Sour taste

A

stimulated by acids, the free H+ of acids blocks K channels in these cells which reduces the outward flow of K ( depolarizing potential )

118
Q

sweet taste

A

Stimulated by glucose, binding of glucose activates a G protein and generate cAMP hat inhibit certain K + channels

119
Q

Bitter taste ( protective mechanism)

A

cells are more diverse and are stimulated by a wide variety of compounds such as alkaline, caffeine, nicotine,, morphine etc. Most poisonous substances have a bitter taste

120
Q

what is the olfactory mucosa ?

A

located on the ceiling of the nasal cavity , contains the olfactory receptor cells , the supporting cells and the basal cells

121
Q

supporting cells

A

secrete mucous

122
Q

basal cells

A

pre cursor for new olfactory receptor cell

123
Q

olfactory nerve

A

formed from the axons of the olfactory receptor cells

124
Q

explain the process of olfaction

A

1) odorants dissolve in the mucous layer and Interact with cilia on the olfactory receptor cells
2) binding of odourant activates G protein and mobilizes cAMP that leads to the opening of NA+ to initiate depolarization

125
Q

where does the output of the ANS come from

A

the hypothalamus, the brainstem and the spinal cord

126
Q

the autonomic nervous system is composed of?

A

The sympathetic nervous system and the parasympathetic nervous system

127
Q

sympathetic nervous system

A

primary role is to stimulate fight or flight response

128
Q

parasympathetic nervous system

A

responsible for the body rest and digest activities ( digestion , urination and salivation

129
Q

two neuron chain

A

connects the CNS to the effector . The cell body of the first neuron is located within the CNS and its first axon

130
Q

where do the fibres of the SNS originate ?

A

the thoracic and lumbar regions of the spinal cord , the preganglionic fibres are short and terminate on the ganglia on spinal cord

131
Q

Long post ganglionic fibres of THE SNS ?

A

terminate on the effector organs

132
Q

preganglionic fibres of PNS?

A

arise from the brink or lower spinal cord , the pre ganglionic fibres are long and terminate in the ganglia located close to the effector organ

133
Q

Pre ganglionic fibres of both the PNS and SNS use which neurotransmitter ?

A

ACh( Acetylcholine )

134
Q

postganglionic fibre PNS

A

Use ACh, and are called cholinergic fibres

135
Q

post ganglionic fibre SNS

A

use Norepinephrine(noradrenaline) and are adrenergic fibres

136
Q

Dual innervation

A

almost all effector organs receive input from both the sympathetic and parasympathetic systems ( not kidneys and adrenal glands)

137
Q

Effect of the heart of SNS and PNS

A

SNS: increased heart rate, increased force of contraction
PNS: decreased heart rate

138
Q

Effect of the eye of SNS and PNS

A

SNS: dilation of pupil ( far vision)
PNS: adjustment of eye for near vision

139
Q

Effect of Digestive track for PNS and SNS

A

SNS: decreased motility( movement contraction of sphincters , inhibition of digestive secretions
PNS increased motility , relaxation of sphincter

140
Q

Effect of blood vessels for PNS and SNS

A

SNS: constriction
PNS: dilation of vessels supplying the penis and clitoris only

141
Q

Lungs effect of PNS AND SNS

A

SNS: dilation of bronchioles( airways ( inhibiton of mucous secretion
PNS: constriction of Bronchioles

142
Q

PNS ans SNS effect on bladder

A 
SNS: relaxation 
PNS contraction ( emptying)
143
Q

sympathetic dominance

A

fight or flight, parasympathetic system is diminished while the sympathetic system is in full force

144
Q

parasympathetic dominance

A

rest and digest, after you’ve had a stressful encounter when the sympathetic division had to work hard , the parasympathetic division takes over to calm the body down

145
Q

what are the dual innervation exceptions

A

1) most arterioles and veins receive sympathetic stimulation only ( exception, penis and clitoris
2) most sweat glands only receive sympathetic stimulation ( release ACh instead
3) the salivery glands receive dual innervation however but both systems can stimulate salivery secretion

146
Q

What does the adrenal gals release with stimulation

A

sympathetic stimulation , releases hormones norepinephrine( associated with sympathetic post ganglionic fibres and 80% epinephrine. Acts as an amplifier of the sympathetic system

147
Q

Cholinergic receptor

A

a receptor on the membrane of cells that responds to acetylcholine

148
Q

Adrenergic receptor

A

A G protein coupled receptor the membrane of cells that responds to catecholamines( epinephrine and norepinephrine

149
Q

Muscarinic receptors ( cholinergic )

A

activated by the mushroom poison muscarine

150
Q

where are muscarinic receptors found ?

A

on the effector cell membranes, they respond to ACh released by PNS post gangilonic fibres . triggers a G protein reaction , results in the opening of Cation channels

151
Q

Nicotinic receptors (cholinergic )

A

activated by the tobacco plant

152
Q

where are nicotinic receptors found ?

A

on cell bodies of postganglionic cells in all autonomic ganglia and bind to ACh

153
Q

Norepinephrine is released from what 2 places?

A

both as a neurotransmitter from sympathetic post ganglionic fibres and as a hormone from the adrenal medulla

154
Q

alpha receptors ( adrenergic )

A

A1 and A2 receptors have greater sensitivity for norepinephrine and epinephrine

155
Q

all adrenergic receptors do what ?

A

activate G proteins

156
Q

A2 activation

A

surpasses the cAMP pathway

157
Q

A1 activation

A

activates the CA+ second messenger system

158
Q

Beta receptor

A

B2 receptors have greater affinity for epinephrine than B1 . B1 respond equally to norepinephrine and epinephrine. Both enhance the cAMP pathway

159
Q

A1 receptors are almost always ?

A

excitatory and are expressed in smooth muscle cells of blood vessels , stimulation cause contraction

160
Q

A2 ?

A

decrease of contraction

161
Q

B1 is almost always?

A

excitatory and are primarily found in the heart

162
Q

B2 is almost always ?

A

generally inhibitory , and primarily found in smooth muscle cells of arterioles and respiratory airway

163
Q

Somatic nervous system

A

comprised of the axons that innervate skeletal muscle under voluntary control

164
Q

where are cell bodies of motor neurons located ?

A

located in the ventral horn of the spinal cord and heir axons terminate directly on their effector

165
Q

motor neurons release what from being stimulated ?

A

acetylcholine - result is most contraction

166
Q

relaxation only occurs in the somatic nervous system through ?

A

by decreasing the excitability of the motor neurons

167
Q

Upper motor neurons

A

originate in the brain stem or the motor region of cerebral cortex

168
Q

what is the role of the upper motor neurons ?

A

carry motor information from the upper motor neurons down to the lower ones. Upper motor neurons descend in the spinal cord

169
Q

what parts of the brain send info to the upper neurons?

A

the cortex, the basal nuclei, the cerebellum and the brainstem

170
Q

motor neurons accept what ?

A

collection of both excitatory and inhibitory signals to decide whether or not to generate action potentials and contract the muscles through the lower neurons

171
Q

Lower motor neurons

A

located in the anterior grey column, anterior nerve root or the cranial nerve nuclei of brainstem

172
Q

Neuromuscular junctions

A

small space between the terminal end of a motor neuron and muscle fibre, this is where neurotransmitter from the neuron stimulates the muscle fibres

173
Q

explain the release of neurotransmitters for the neuromuscular junction

A

an action potential in a motor neuron is propogated to the axon terminal ( terminal button)
2)the an action potential reaches the terminal button, voltage gated Cachannels open allowing Ca to enter in the terminal button which triggers exocytotic release of vesicles containing ACh into cleft
3) release of ACh bind to nicotinic receptors on the motor end plate and open cation channels . Net influx of positive charge , membrane potential depolarizes ( known as end plate potential ) which are graded
4) initation of action potential end plate is sufficiently depolarized , the muscle membrane gets influenced and NA+ channels begin to open
When sufficient Na channels are open, the muscle fibres reaches threshold and the wave of excitation radiates out from the motor end plate causing muscle contraction
\5 inactivation of ACh through the enzyme acetylcholinesterase , need to deactivate ACh otherwise muscle would always stay in excited state How

174
Q

How would venom from a spider effect the neuromuscular junction

A

causes an explosive release of ACh from all cholinergic sites. This release overwhelms the the ability of acetylcholinesterase to rapidly inactivate it which results in prolonged depolarization

175
Q

Botulinum Toxin

A

blocks the release of ACh from the terminal button meaning the skeletal muscle cannot be excited and paralysis occurs

176
Q

Curare

A

action occurs on the motor end plate where it binds to the same receptor as ACh however does not cause and end plate potential and blocking ACh from binding to them which causes muscle weakness and paralysis

physiology 215 (3 decks)

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