Exam 2 Flashcards
(285 cards)
1
Q
what is the absolute refractory period?what is its function?
A
a segment of action potential that starts from the opening of activation gates and ends right before inactivation gates begin to open.
*cannot induce a second action potential during this time *insures action potential only travels in one direction
2
Q
what is the voltages for neuron resting potential and action potential? what is the voltage threshold for action potential to be triggered?
A
resting potential = -70mV
action potential = +30mV
threshold = -55mV
3
Q
what are the 9 steps of membrane potential?
A
1) resting membrane potential
2) depolarizing stimulus from graded potential
3) membrane depolarizes to threshold. voltage gated Na+ and K+ channels begin to open
4) rapid entry of Na+ depolarizes the cell
5) once at AP voltage, Na+ channels close and slower K+ continue to open
6) K+ moves from cell to ECF which repolarizes the cell
7) K+ channels remain open allowing K+ to continue to exit cell which hyperpolarizes it
8) K+ channels close allowing less K+ to leak from cell
9) cell returns to resting ion permeability and resting membrane potential.
4
Q
what are the positions of Na+ activation and inactivation gates during the various voltages in membrane potential?
A
- At resting membrane potential (-70mV)- activation gate is closed, inactivation gate is open
- At or suprathreshold (-55mV +)- activation gate begins to open and inactivation gate is open
- depolarization (-55mV - +30mV) - activation and inactivation gates are both fully open
- At action potential voltage (+30mV) - activation gate remains open and inactivation gate is closed
- hyperpolarization(-80mV - -70mV) - activation gate begins to close and inactivation gate opens
5
Q
describe the position of voltage gated potassium channels in the various phases of membrane potential
A
- resting membrane potential - gate closed
- depolarization - gates closed
- action potential voltage (+30mV) - gates are beginning to open
- repolarization - gate is opened
- hyperpolarization - closing but not yet fully closed
6
Q
depolarization of action potential due to rapid entry of Na+ into the cell is an example of which type of feedback loop and why?
A
it is an example of a positive feedback loop. the rapid entry of sodium depolarizes the membrane potential and leads to the sodium activation gates opening more leading to more sodium entering and more polarization.
7
Q
how is depolarization stopped during action potential?
A
sodium inactivation gates close
8
Q
what is membrane potential relative refractory period and when does it end?
A
it begins when the sodium channel active and inactive gates begin to reset to resting positions while potassium channels remain open. when all channels are at resting state, the refractory period is over.
9
Q
in which refractory period can a second action potential be produced?
A
if a STRONG stimulus is experienced during the relative refractory period a second action potential may be produced
10
Q
what is saltatory conduction?
A
in myelinated axons, action potential is transmitted from node of ranvier to node of ranvier.this is how action potential is able to move so rapidly while maintaining a constant strength
11
Q
how does saltatory conduction make it possible for action potential to maintain a constant strength?
A
a new action potential is created at each node of ranvier
12
Q
where are voltage gated channels found on neuron axons?
A
at each node of ranvier
13
Q
what is the purpose of myelin sheath on axons?
A
insulates axons to prevent voltage from escaping
14
Q
how fast does action potential travel down a myelinated axon?
A
2 meters per second
15
Q
how does action potential transmit the strength of graded potential?
A
a lower frequency of consecutive action potentials for lower strengths and a higher frequency of consecutive action potentials for higher strengths
16
Q
what prevents action potential from occuring simultaneously or moving backwards?
A
the absolute refractory period
17
Q
what is normokalemia and what affect does this have on membrane potential?
A
normokalemia = normal K+(potassium ion) concentration in the ECF. this is the optimal condition for membrane potential resting state and will not allow subthreshold graded potential to fire an action potential. further it will allow for the firing of action potential when a suprathreshold graded potential is received
18
Q
what is hyperkalemia and what affect does this have on membrane potential?
A
hyperkalemia is a condition where there is a higher than normal concentration of k+ (potassium ions) in the ECF. the lower concentration gradient leads to less potassium ions diffusing out of cells and resulting in a higher positive ion concentration within the cell. this raises the membrane potential resting state to a more positive number that is closer to threshold. weak graded potentials that would normally be subthreshold can now result in the firing of action potential.
19
Q
what is hypokalemia and what affect does this condition have on membrane potential?
A
hypokalemia is a condition where there is a lower than normal concentration of K+(potassium ions) in the ECF. this leads to a steeper concentration gradient on potassium and a lower concentration of positive potassium ions within the cell. this lowers (hyperpolarizes) the membrane potential resting state to a value that is more negative bringing it further from the threshold. graded potentials received at the trigger zone in the axon hillock that would normally be at or suprathreshold are now too weak to fire an action potential.
20
Q
what is the synaptic cleft?what is the postsynaptic neuron?what is the presynaptic neuron?
A
1) synaptic cleft is the space between the axon terminal of the presynaptic neuron and the body or dendrite of the postsynaptic neuron (or effector cell). the location where neurotransmitters are sent and received
2) the postsynaptic neuron is the neuron in a synapse that is receiving stimuli
3) the presynaptic neuron is the neuron that is sending neurotransmitters to the postsynaptic neuron or effector cell
21
Q
what are the 5 steps associated with neurotransmitter communication in a synapse?
A
1) action potential arrives at the axon terminal and depolarizes it.
2) the depolarization opens voltage gated Ca2+(calcium) channels allowing calcium to enter the cell
3) entry of calcium into the cell triggers exocytosis of neurotransmitter filled vesicles
4) neurotransmitters diffuse across the synaptic cleft and binds to receptors on the postsynaptic cell.
5) the binding of neurotransmitters initiates a response in the postsynaptic cell
22
Q
what is acetylcholine and what is it able to bind to?
A
acetylcholine (ACh) is a neurotransmitter that is only able to bind to a classification of receptors called cholinergic receptors
23
Q
what are the two types of cholinergic receptors?
A
nicotinic cholinergic receptors (nAChR)
muscarinic cholinergic receptors (M)
24
Q
where are nicotinic cholinergic receptors found?
where are muscarinic cholinergic receptors found?
A
nicotinic cholinergic receptors are found are found on skeletal muscle cells(voluntary effectors), autonomic neurons(involuntary), and in the CNS
muscarinic cholinergic receptors are found on smooth and cardiac muscle cells(involuntary effectors), endocrine and exocrine glands(involuntary effectors), and in the CNS
25
what is epinephrine and norepinephrine, what do they bind to, and where are their receptors found?
they are neurotransmitters, they bind to alpha adrenergic or beta adrenergic receptors, and receptors are found in smooth and cardiac muscle, endocrine and exocrine glands, and the CNS
26
what is dopamine, what does it bind to, and where are its receptors found?
a neurotransmitter that binds to dopamine receptors and is found only in the CNS
27
what is serotonin, what does it bind to, and where are its receptors found?
a neurotransmitter that binds to serotonergic receptors that are found only in the CNS
28
what is histamine, what does it bind to, and where are its receptors found?
neurotransmitter that binds to histamine receptors that are found only in the CNS
29
how is dopamine, norepinephrine, and epinephrine produced?
1) it starts off with a single amino acid called tyrosine
2) tyrosine is converted into DOPA
3) DOPA is converted into dopamine
4) dopamine is converted into norepinephrine
5) norepinephrine is converted into epinephrine
30
how is serotonin produced?
the amino acid tryptophan can be converted into serotonin
31
what is neurotransmitter termination?describe the methods of termination.
neurotransmitter action terminates when neurotransmitters are broken down, taken up by cells, or diffuse away from the synapse. neurotransmitters can be:
1) either taken into glial cells or back into axon terminals through protein channels
2) broken down and inactivated by enzymes found on the postsynaptic cell
3) diffused out of the synaptic cleft either into the ecf or blood stream
32
how is acetylcholine produced?
* acetylcholine is broken down by the enzyme acetylcholinesterase
* acetate is transported into the post synaptic cell and choline enters the presynaptic axon terminal through an Na+ assisted symport carrier
* choline reacts with acetate from acetyl CoA (from pyruvate metabolism) via an enzyme and acetylcholine is produced.
* the CoA unit returns to the mitochondria and returns to pyruvate metabolism
33
what is the enzyme that breaks down acetylcholine called?
acetylcholinesterase
34
what is membrane potential?
electrical disequalibrium between ICF and ECF
35
what is membrane potential due to?
ion movement through leaky ion channels
36
what are the two types of membrane potentials we are discussing in class?
graded potential and action potential
37
what is resting membrane potential and what is it due to?
membrane potential has reached a steady state nd is not changing. this is mostly due to K+ (potassium ions)
38
what is the resting membrane potential for a neuron?
-70mv within the cell
39
what are the functional classifications of neurons?
1) sensory neurons
| 2) motor neurons
40
what are the structural classifications of neurons and where are they found?
1) unipolar neurons(somatic sensory)
2) bipolar neurons(special sensory- hearing, vision, smell,)
3) multipolar neurons(motor function (efferent and CNS)
41
what are the branches of axon right before axon terminals called?
collaterals
42
what are nuclei in the nervous system?
a grouping of neuron cell bodies within the CNS
43
what are ganglia?
a grouping of neuron cell bodies outside the CNS (in the PNS)
44
what is a tract in the nervous system?
a grouping of nerve fibers that interconnect regions of the CNS
45
what are nerves?
bundles of axons in the PNS
46
what is membrane potential depolarization?
membrane potential becomes more positive that resting membrane potential.(creates an electrical signal)
47
what is repolarization?
depolarized membrane potential returns to resting potential
48
what is hyperpolarization?
when membrane potential becomes more negative than its resting membrane potential
49
what chemicals do chemically gated protein channels in neurons respond to?
neurotransmitters, they bind to the receptor which opens the protein channel
50
what type of gated protein channel responds to membrane potential?
voltage-gated channel proteins
51
what are characteristics of graded potential?
1) they vary in strength
| 2) they travel only short distances and lose strength the further they travel
52
where is graded potential generated and how?
neuron cell bodies and dendrites that receive stimuli from action potentials in other cells and generate a graded potential that may go on to trigger action potential in its own cell
53
how and where is action potential generated in neurons?
it responds to at or suprathreshold graded potentials that are generated from action potentials originating from other cells. if the graded potential sensed by the axon hillock meets or exceeds a threshold, it generates action potential.
54
how much strength does action potential lose as it travels?
none, action potential maintains a constant strength
55
what happens if graded potential detected at the axon hillock does not meet or exceed action potential threshold?
nothing, the threshold must be met to generate action potential.
56
what is the transporter called that allowed choline to travel back into the neuron called and why?
sodium linked choline transporter because it is a symport transporter that requires sodium to drive the transportation of choline across the membrane
57
describe cholinergic nicotinic receptors
they are chemically gated antiport transport proteins that respond to acetylcholine and allow sodium to enter the cell and potassium to leave the cell which produces graded potential
58
describe how a muscarinic cholinergic receptor works
1) acetylcholine binds to the muscarinic cholinergic receptor
2) binding causes the stimulatory g-proteins to break off of the icf side of the receptor
3) the the beta and gamma proteins are stuck together but break away from the alpha protein and float further into the cytoplasm
4) the alpha protein travels along the cell membrane until it reaches a protein structure which triggers a series of chemical reactions that open a transport protein
59
what binds to adrenergic receptors?
norepinephrine
60
what is a g-protein?
it is the alpha beta and gamma protein when it is attached to one another and still attached to the receptor
61
what are the steps related to the adrenergic receptor process?
1) norepinephrine or epinephrine binds to the adrenergic receptor
2) the G-protein attached to the receptor is activated. alpha breaks away from beta and gamma proteins and travels along the plasma membrane until it reaches adenylate cyclase. beta and gamma proteins float off in the cytoplasm together
3) adenylate cyclase is activated and reacts with ATP molecules to form cAMP (second messenger)
4) cAMP activates protein kinase A
5) Protein kinase A phosphorylates a transport protein
6) the protein channel either opens or close to allow or prevent the movement of ions across the cell membrane which produces either an excitatory or inhibitory response
62
what does ICR stand for?
ion channel receptor
63
what does GPCR stand for?
G-protein coupled receptor
64
what are the two postsynaptic responses?
EPSP- excitatory postsynaptic potential
| IPSP- Inhibitory postsynaptic response
65
describe EPSP what receptors produce only EPSP?
excitatory postsynaptic potential depolarizes the postsynaptic cell.nicotinic cholinergic receptors
66
describe IPSPwhat receptors are capable of producing IPSP?
inhibitory postsynaptic potential hyperpolarizes the cell to prevent graded potential from firing action potential.
muscarinic cholinergic receptors and adrenergic receptors
67
what happens when graded potential originating from different synapses in one cell body meet one another?
they join together. IPSP will join together to make a stronger graded potential.
if IPSP meets EPSP, the EPSP will reduce the strength of graded potential.
68
what does the nervous system start out looking like, what is it called?
looks like a tube it is called the neural tube
69
define rostral and caudal when it concerns the brain
rostral is the head end (anterior)caudal is the tail end or (posterior)
70
define rostral, caudal, ventral, and dorsal when it concerns the spinal cord
rostral is superior
caudal is inferior
dorsal is posterior
ventral is anterior
71
what are the three primary vesicles in a developing nervous system?
```
top = prosencephalon(forebrain)
middle = mesencephalon(midbrain)
bottom = rhombencephalon(hindbrain)
```
72
what does the prosencephalon develop into?
telencephalon (2 hemispheres) and the diencephalon (includes thalamus and hypothalamus)
73
what does the mesencephalon develop into?
the midbrain
74
what does the rhombencephalon develop into?
the metencephalon which further develops into the pons and cerebellum
and the myelencephalon which further develops into the medulla
75
what is the difference in what is contained in the white matter vs. grey matter?
white matter contains myelinated axons, grey matter contains cell bodies and dendrites
76
what type of information does the anterior (ventral) and posterior (dorsal) spinal nerves carry?
posterior (dorsal) nerves carry sensory information afferently to the CNSanterior (ventral) spinal nerves carry efferent motor signals to effectors
77
where do ascending and descending tracts in the spinal cord take information?
ascending tracts take information to the braindescending tracts carry commands to motor neurons
78
what is the function of white matter in the spinal cord?
it transmits information to and from the brain
79
what is a spinal reflex?
afferent signals bypass the brain and travel through the cell bodies of the grey matter and send signals directly to effectors( skeletal muscles) creating a very fast response
80
what type of information does the somatosensory tract carry? what are the pathways?
the somatosensory tracts carries information related to general senses to the primary somatosensory area of the cerebral cortex
POSTERIOR COLUMN-MEDIAL LEMNISCUS PATHWAY:
1) signal sent from receptor through the posterior spinal nerve
2) from posterior spinal nerve through posterior column of the spinal cord
3) from posterior column through the "olive" (nuclei of the medulla)
4) from the olive through the medial lemniscus of the midbrain
5) from the medial lemniscus through the thalamus
6) from the Thalamus to the post central gyrus (primary somatosensory area of cerebral cortex)
ANTEROLATERAL PATHWAY (SPINOTHALAMIC):
1) signal sent from receptor through the posterior spinal nerve
2) from the posterior spinal nerve through the anterior and lateral spinothalamic tract in the spinal cord
3) from the spinothalamic tracts through the medial lemniscus
4) from the medial lemniscus through the thalamus
5) from the thalamus to the post central gyrus (primary somatosensory area of cerebral cortex)
81
what is general sensory?
1) fine touch
2) proprioception
3) vibration
4) pain
5) cold and warmth
6) tickle
7) itch
82
what is proprioception?
perception of the position of your joints in relation to the space around you
83
1) what is the posterior column-medial lemniscus pathway of the somatosensory tract used for?2) what is the anterolateral pathway used for?
1) used to transmit information related to fine touch, proprioception, and vibration
2) used to transmit information related to pain, cold, warmth, tickle, and itch
84
what is the olive in the medulla?
the olive is the nuclei in the medulla it is a sensory relay station
85
what type of information does the corticospinal tract carry?what is its pathway?
carries motor information from the brain to the spinal cord to be transmitted to effectorsCORTICOSPINAL TRACT PATHWAY:
1) signals are carried from the precentral gyrus (primary motor area of the cerebral cortex) through the medulla pyramids
2) from the medulla pyramids through the left lateral and the right anterior corticospinal tracts
3) from the left lateral and right anterior corticospinal tracts to the anterior spinal nerve on the opposite side the signal was sent.
86
what are the pyramids of the medulla?
descending tracts that carry motor information
87
what is dessucation?
the crossing over of tracts to the other side of the nervous system. signals sent from the right side of the brain cross over to the left at the dessucation point which is in the medulla
88
what type of information passes through the medulla pyramids?
descending motor signals
89
what type of information passes through the olive (nuclei of the medulla)?
ascending sensory information
90
what is the function of the thalamus?
it is the main sensory relay station. all sensory signals except olfaction travel through the thalamus
91
where is the cardiovascular center in the nervous system and what is its function?
it is located in the medulla and its function is to control heart rate and contractility
92
what type of matter is located in the pyramids and olive of the medulla and the cardiovascular center?
grey matter
93
where is the respiratory center located and what are their functions?
there is one respiratory center located in the medulla and another in the pons. they work together to control frequency and strength of breathing
94
what is contained within the pons?what type of matter is the pons made up of?
1) motor tracts from cerebrum to cerebellum and medulla
2) sensory tracts to thalamus
3) respiratory center and tracts to respirator center in medulla
the pons is made up of lots of white matter
95
what is the official name for the midbrain?
the mesenchephalon
96
what part of the mesencephalon controls involuntary/reflexive eye movement?
the superior colliculi
97
where in the mesencephalon does auditory information integration take place?
the inferior colliculi
98
describe the communication between the superior and inferior colliculi in the mesencephalon
they work with one another so that reflexive eye movement controlled by the superior colliculi can be used when a loud noise is sensed by the inferior colliculi
99
are there tracts found in the mesencephalon? if so which types?
yes, both sensory and motor tracts
100
what is the thalamus composed of?
various nuclei (neuron cell bodies and dendrites
101
what is the function of the thalamus?
* it processes general and special sensory signals and relays them to their targeted locations of the brain
* regulates levels of awareness
102
what are the functions of the hypothaamus?
1) activates sympathetic nervous system
2) maintains body temperature
3) controls body osmolarity
4) controls reproductive functions
5) controls food intake
6) interacts with the limbic system to influence behavior and emotions
7) influences cardiovascular center in the medulla
8) secrets trophic hormones that control the release of hormones from the anterior pituitary gland
103
what is catecholamine?
a group of hormones that includes epinephrine, norepinephrine, and dopamine
104
how does the hypothalamus activate the fight or flight response of the sympathetic nervous system?
it controls catecholamine release from the adrenal medulla
105
how is the hypothalamus involved in blood glucose regulation?
it acts on the pancreas to release either insulin or glucagon
106
where in the brain is temperature sensed?
in the hypothalamus
107
how does the hypothalamus control body osmolarity?
it motivates thirst and drinking behavior and stimulates the secretion of ADH (vasopressin)
108
where is vasopressin produced?where is it stored?
in the supraoptic and paraventricular nuclei of the hypothalamus.it is stored in the posterior lobe of the pituitary gland
109
where is oxytocin produced and stored?
it is produced in the supraoptic and paraventricular nuclei of the hypothalamus and is stored in the posterior lobe of the pituitary gland
110
what are the functions of oxytocin?
promotes uterine contraction and lactation
111
how does the circadian rhythm work?
the suprachiasmatic nuclei send information related to how much day light is available to the pineal gland (where melatonin is stored) in times of darkness, melatonin release is promoted and makes us tired.
112
what are the functions of the cerebellum?
1) processes sensory information
| 2) coordinates the execution of movement
113
how do the hemispheres of the brain communicate?
through the corpus callosum
114
what is the function of the basal nuclei(ganglia)?
subconscious control of skeletal muscle.
115
where is the primary motor cortex?where is the primary somatosensory cortex??
the primary motor cortex is located on the pre-central gyri of the frontal lobe and the primary somatosensory cortex is located on the post-central gyri of the parietal lobe.
116
what are the areas of the brain that process taste and smell signals?
taste is processed in the gustatory cortex located in the insula under the frontal lobesmell is processed in the olfactory cortex located in the insula beneath the temporal lobe
117
where is vision and hearing processed in the brain?
vision is processed in the visual cortex of the occipital lobe and sound is processed in the auditory cortex of the temporal lobe
118
describe cerebral lateralization
cerebral lateralization is where each hemisphere of the brain is associated with different functions. the left side of the brain deals with things such as math, writing, logic, scientific skills, and language
the right side deals with music, art, emotional expression, creativity, imagination, and spatial awareness.
119
what method is used to measure sleep waves?
EGG (electroencephalography)
120
describe the state a person is in the various levels of brain waves
Beta- awake, excited, and eyes open
Alpha- awake, relaxed, and eyes closed
Theta- asleep, deep relaxation
Delta- deep sleep, dreamless
121
1:37:17
122
what are the stages of sleep and how long is each cycle?
beta, theta, delta, and REM. this occurs in 90 minute intervals
beta, theta, and delta are non rem and delta is broken into 2 stages.
123
the brain waves in rem is similar to what other stage?
beta
124
what is rem also known as?
paradoxical sleep because its a deep sleep where brain waves are similar to those of awake state
125
what happens in REM sleep?
vivid dreams
increased metabolism
major muscle groups are paralyzed
126
what is the purpose of sleep?
cellular repairs and memory organization
127
which stage of sleep represents the lowest level of consciousness?
delta (stage 3 and 4)
128
what stage of sleep are you in when you wake up?
REM
129
which dreams do you remember?
the last dream that you had
130
what are parasomias and what types are common?
```
sleeping disorders
COMMON:
insomnia
sleep walking
night terror
sleep apnea
```
131
what is the only thing we do know about the cause of sleep walking
genetics play a role
132
what stages of sleep does sleep walking and night terror occur?
stages 3 and 4
133
what is memory?
the ability to retain and recall information
134
what is short term memory?
short term memory is a memory that disappears unless an effort is made to make it permanent
135
what is long term memory?
memory that is stored and retrievable
136
what is the difference between reflexive and declarative long term memory?
* reflexive does not take conscious thought and is acquired slowly through repetition
* declarative takes conscious thought to recall information and depends on higher level thinking such as inference comparison and evaluation.
137
what type of memory can be demonstrated?what type of memory can be reported verbally?
reflexive memory
| declarative long term memory
138
what is the difference between anterograde and retrograde amnesia?
anterograde amnesia is a disorder where the patient cannot store long term memories after the trauma that caused the amnesia but remembers everything before the trauma clearly
retrograde amnesia is a disorder where the patient is able to store long term memory after the trauma that caused the amnesia but cannot recall anything that occured before the trauma
139
what is the most common form of dementia?
alzheimers
140
what is dementia?
a decline in mental ability
141
what happens to the brain in patients with alzheimers?
the brain shrinks
142
what happens to neurons in alzheimers?
neurofibrillary tangles in the neurons and amyloid plaques in the ecf
143
where is the wernickes area of the brain and what is its function?
it is located on the left temporal lobe right on the boarder to the occipital lobe.its responsible for the comprehension of vocal, written, and signed language and storing information for arranging learned vocabulary into meaningful speech
144
where is the brocas area and what is the brocas function?
located in the left frontal lobe where the temporal, parietal, and frontal lobe meet.it is responsible for speech production and articulation
stores information needed for speech production and programs motor cortex to move tongue, lips, and speech muscles
145
what is aphasia?
a group of speech/language disorders
146
what is receptive aphasia?what is the symptom?
receptive aphasia is due to damage in the mernickes area of the brain that makes it difficult for a patient to understand both written and spoken language. patient will produce meaningless speech
147
what is expressive aphasia?what is the symptom produced?
expressive aphasia is due to damage to the brocas area of the brain and results in the loss of ability to produce spoken or written language
148
what is mechanical aphasia?
a form of aphasia where damage to the motor cortex inhibits a patients ability use vocal muscles and makes it difficult to produce spoken language
149
what are the subcatagories and effectors of the autonomic nervous system?
sympathetic and parasympathetic nervous systemtheir effectors are smooth muscle, cardiac muscle, and endocrine and exocrine glands
150
what are the functions of the ANS?
to maintain homeostasis through antagonistic control via parasympathetic and sympathetic nervous systems
151
describe antagonistic responses of the ANS
while sympathetic nervous system is excitatory, parasympathetic is inhibitory
152
what is dual innervation by the ANS?
where a target organ has nerves that accept signals from both parasympathetic and sympathetic nervous systems
153
what organs do not have dual innervation from the sympathetic and parasympathetic nervous systems?
blood vessels and sweat glands. they only have innervation from the sympathetic nervous system
154
where are neuron cell bodies that transmit signals from the ANS located in the spinal cord?
in the lateral horn of the spinal cord
155
what is a 2 neuron system?
a neuron housed in the spinal cord (CNS) sends signals to another neuron located in a ganglion. the ganglionic cell body then transmits a signal to a motor effector
156
what is a neuroeffector junction?
the point where an axon terminal synapses with an effector
157
what type of membrane potential response is produced with a nicotinic receptor?
EPSP excitatory postsynaptic potential
158
how many neurons are used in each pathway of the ANS?
the ANS always uses the 2 neuron system to transmit signals to effectors
159
in a sympathetic pathway: what is the neurotransmitter that the preganglionic neuron releases and what receptor does it bind to?
axon terminals of the preganglionic neuron releases ACh (acetylcholine) and it binds to nicotinic cholinergic receptors on the post ganglionic neuron in the ganglion
160
in a sympathetic pathway: what type of neurotransmitter is released from the axon terminal of the postganglionic neuron and what type of receptor does it bind to?
norepinephrine is released from the axon of the postganglionic neuron and it binds to adrenergic receptors on the effector cell.there are various types of adrenergic receptors (alpha 1, alpha 2, beta 1, beta 2, and beta 3)
161
what is the second messenger of the adrenergic receptor response?
cAMP (cyclic adenosine monophosphate)
162
what are the possible methods of norepinephrine degredation?
1) it can diffuse away from the synaptic cleft either into a blood vessel or in the ecf
2) it can be taken back into the cell through active transport and either be repackaged or taken into the mitochondria and broken down by monoamine oxidase (MAO)
163
what is norepinephrine made of?
amino acid tyrosine is the building block for norepinephrine.tyrosine>DOPA>dopamine>norepinephrine>epinephrine
164
in a parasympathetic pathway: what neurotransmitter is released by the axon terminal of the preganglionic neuron and which receptors does it bind to?
acetylcholine is released by the preganglionic neuron and it binds to nicotinic receptors on the cell body of the postganglionic neuron
165
in the parasympathetic pathway: what neurotransmitter is released by the axon terminal of the postganglionic neuron and which receptors does it bind to?
acetylcholine is released from the postganglionic neurons axon terminal and it binds to muscarinic cholinergic receptors on the target effector cell
166
PARASYMPATHETIC: what effect does muscarinic cholinergic receptors have on effector cells in the heart and digestive tracts?
muscarinic cholinergic receptors in the heart signal potassium channels to open which hyperpolarizes it produces a inhibitory response which causes a slower heart rate
muscarinic cholinergic receptors in the digestive tracts open calcium or sodium channels and close potassium channels which depolarizes cells causing excitation in target cells and causes smooth muscle in the digestive tract to contract
167
which cranial nerve controls the parasympathetic nervous system?
the vagus nerve
168
what is the adrenal medulla aka?
modified sympathetic ganglion
169
how do neuron cell bodies in the adrenal medulla differ from other neurons in the nervous system?
neurons in the adrenal medulla do not have axons
170
what is the adrenal sympathetic pathway?
neuron cell body in the lateral horn of the spinal cord > cell body in the adrenal medulla
171
which part of the spinal cord houses neurons associated with the adrenal sympathetic pathway?
the thoracic region of the spinal cord
172
describe the activity of neurotransmitters in the adrenal sympathetic pathway
preganglionic neurons release acetylcholine from its axon terminal which binds to nicotinic cholinergic receptors on the neuron cell bodies in the adrenal medulla.
postganglionic neurons in the medulla then release norepinephrine and epinephrine from their cell bodies into the blood stream
norepinephrine and epinephrine are considered to be hormones at this point and travel through the blood to their targets75%epinephrine and 25%norepinephrine is released
173
describe the effects that the parasympathetic and sympathetic nervous systems have on the heart
the sympathetic nervous system will cause increased heart rate and contractility via beta1 adrenergic receptorsthe parasympathetic nervous system will cause the heart to beat slower only
174
describe the effects of the autonomic nervous system on blood vessels
the sympathetic nervous system will cause blood vessels to either dilate or constrict depending on where in the body they are located.
the parasympathetic nervous system has no effect on blood vessels
**alpha1 adrenergic receptors cause BV constriction
**beta2 adrenergic receptors will cause BV dilation
175
describe autonomic nervous system effects on the lungs
the sympathetic nervous system will cause bronchiole dilation via beta2 adrenergic receptorsthe
parasympathetic nervous system will cause bronchiole constriction
176
describe autonomic nervous system effects on the pupils
sympathetic nervous system causes pupils to dilate
| parasympathetic nervous system causes pupils to constrict
177
describe effects the ANS have on the pancreas
parasympathetic nervous system stimulates increased enzyme(exocrine) and insulin(endocrine) secretion
sympathetic nervous system stimulates a decrease in enzyme and insulin secretion
178
describe effects of the ANS on the digestive tract
sympathetic nervous system decreases motility and secretion
| parasympathetic nervous system increases motility and secretion
179
all receptors on target effectors in the parasympathetic nervous system respond to which signals?
signals from muscarinic cholinergic receptors
180
in the sympathetic nervous system, all receptors on target effectors respond to signals from what?
adrenergic receptors that respond to epinephrine
181
describe effect the sympathetic nervous system has on these target effectors:
1) adrenal medulla
2) kidney
3) urinary bladder
4) male and female sex organs
1) secretes catecholamines
2) increases renin secretion
3) urinary retention
4) (male) ejaculation
182
describe the effects the parasympathetic nervous system has on these target effectors:
1) adrenal medulla
2) kidney
3) urinary bladder
4) male and female reproductive system
1) none
2) none
3) release of urine
4) erection
183
which receptor in the kidneys is responsible for accepting epinephrine and causing an increase in renin secretion?
beta1 adrenergic receptors
184
where in the CNS are neurons for the sympathetic and parasympathetic nervous systems located?
sympathetic neurons are located in the lateral horn of the spinal cord
parasympathetic neurons are located in the brainstem and the sacral region of the spinal cord
185
what type of stimuli do chemoreceptors detect?
chemicals like oxygen, PH, and various organic molecules such as glucose
186
what do mechanoreceptors respond to?
mechanical stimuli such as pressure(baroreceptors), cell stretch (osmoreceptors), vibration, acceleration, and sound
187
what do photoreceptors respond to?
photons (light)
188
what do thermoreceptors respond to?
temperature
189
whats the difference between graded potential and receptor potential?
just where theyre generated. graded potential is generated in neuron cell bodies and receptor potential is generated in receptors
190
what part of the body has the most sensory receptors?
hands and face
191
what is a tonic receptor?
a receptor that does not adapt or is very slow to adapt to a stimulus. while a stimulus is present they will continue to produce action potential
192
what is a phasic receptor?
a receptor that quickly adapts to a stimulus and stops producing action potential after a short time. receptors for odor, touch, and temp are phasic
193
what do photoreceptor cones detect?
colored light
194
what do photoreceptor rods detect?
blacks and greys
195
describe light control in the eye
in bright light situations, parasympathetic nervous system contracts the circular layer of smooth muscle in the iris constricting it and allowing less light to enter the eye
in stressful or low light situations the sympathetic nervous system contracts the radial layer of smooth muscle in the iris which dilates the eye and allows more light to enter the eye (increased vision)
196
what is accommodation of the eye?
the ciliary muscles either contract or relax causing various tensions on the suspensory ligaments and changing the shape of the lens to focus light on the fovea centralis for optimal vision
197
what happens to the lens to accommodate for distant vision?
ciliary muscles relax causing tension on the suspensory ligaments. this causes the lens to take on a flat and thin shape
198
how does the lens accommodate for near vision?
ciliary muscles contract causing the suspensory ligaments to lose tension. this allows the lens to take on a thick and round shape.
199
what is presbyopia?
the loss of the lenses ability to accommodate due to a loss of flexibility of the lens
200
what is visual acuity?
vision sharpness
201
what is emmetropia?
normal eye ball shape and image focus on retina
202
what is myopia?how is it corrected?
an abnormally curved cornea or the eyeball is longer than normal. this causes the image to fall before the cones of the fovea centralis.
this causes nearsightedness
glasses with a concave lens
203
what is hyperopia?how is it corrected?
the eyeball is shorter than normal causing the image to fall after the cones of the fovea centralis.
this causes farsightedness
correction: convex lens
204
what is astigmatism
asymmetry of the cornea. this causes you to have 2 focal points within the eye and causes distortion of vision
205
what is rhodopsin, what is its functions, and where is it located?
rhodopsin is a photopigment that detects light. it is located in the membranes of the disks that are located in the top portion of the photoreceptors.
206
what is rhodopsin composed of?
rhodopsin is composed of a protein called opsin and a molecule called retinal
207
what is the structure of rhodopsin in light and dark conditions?
in dark conditions the opsin is enclosed around a bent retinal moleculein light conditions the retinal transforms into a linear shape and separates from the opsin protein.
208
what is the difference between the rhodopsin in rods and the rhodopsin in cones?
the rhodopsin in rods detect dark colors but the rhodopsins in cones are trichromatic and detect reds blues and greens
209
what is the function of rods what is the function of cones?
rods detect dark colors like blacks and greys in light.cones detect color and provide visual acuity
210
which cells in the retina form the optic nerve?
ganglion cells
211
which cells are affected in those with colorblindness?
photoreceptor cones
212
describe phototransduction in a dark condition.
in dark conditions:
* cGMP (cyclic Guanosine Monophosphate) concentrations are high in the ICF which keeps CNG (cyclic nucleotide gated) channels open allowing cations (sodium and calcium) to enter cell which causes cell to depolarize.
* *this depolarization is called dark current.
* depolarization causes neurotransmitters to be released at the synapse to the bipolar cells
213
describe phototransduction in rods and cones in light conditions
light travels through photoreceptor and hits rhodopsin. retinal separates from the opsin protein.
cGMP (Cyclic Guanosine Monophosphate) concentrations in the ICF are low.
CNG (Cyclic Nucleotide Gates) channels close and prevent cations (sodium and calcium from entering the ICF.
The efflux of K+ continues through leaky channels
membrane potential hyperpolarizes to -70mV within the cell.
neurotransmitter release ceases in light conditions
214
what is the phototransduction pathway?
* photoreceptor neurotransmitters either excite or inhibit bipolar cells
* bipolar cells either excite or inhibit ganglion cells (if excited ganglion cells produce action potential)
* Action potential pathway:
1) optic nerve
2) optic chiasm
3) optic tracts
4) lateral geniculate nuclei (thalamus)
5) optic radiation
6) visual cortex
* *some tracts travel to the superior colliculi of the midbrain**
215
where in the brain does the comprehension of a visual image take place?
the wernikes area of the temporal lobe
216
what are the five tastes?
sweetness, sourness, saltiness, bitterness, and umami
217
what type of neurons do taste cells synapse with?
gustatory neurons
218
what are the steps of taste transduction?
SWEET, BITTER, AND UMAMI
1) taste substrate binds to GPCR receptor and releases gustducin
2) gustducin leads to the opening of gated calcium channels in the cell membrane and smooth endoplasmic reticulum
3) calcium travels from ECF and smooth endoplasmic reticulum into the ICF
4) increased calcium concentration in the ICF leads to atp formation
5) ATP is released from cell causing primary gustatory neurons to fire action potentials that are sent to the brain
SALT
1) H+ and Ca++ enters cell and triggers exocytosis and action potential production in the primary gustatory neuron
219
what other sense is taste associated with?
smell
220
what is the pathway of smell?
1) the dendrites of the bipolar olfactory neurons(olfactory nerve) dangles from the top of the nasal cavity and detect chemicals in inhaled air
2) olfactory bipolar neuron axons synapse with the olfactory bulb
3) the signal travels down the olfactory tract to the olfactory cortex
4) the olfactory cortex in the insula relays information to the cerebral cortex and the limbic system
221
SOUNDWAVES: what is the amplitude of a sound wave aka and what is it measured in?
AKA intensity is the strength or loudness of a pitch, it is measured in dB
222
what is a wavelength?
the space between two sound waves
223
what is the frequency of soundwaves and what unit is it measured in?
frequency of soundwaves is how many sound waves occur in 1 second and it is measured in Hz
224
what determines the pitch or tone of a sound?
the frequency of sound waves
225
describe the pathway of sound waves to the round window
1) auricle
2) ear canal
3) tympanic membrane
4) auditory ossicles (malleus, incus, and stapes)
5) oval window
6) perilymph in the vestibular duct
7) vestibular membrane
8) cochlear duct
9) basilar membrane
10) tympanic duct
11) round window
226
what is the vestibular duct, cochlear duct, and tympanic duct filled with?
vestibular and tympanic ducts are filled with perilymph
| cochlear duct is filled with endolymph
227
what is the purpose of the auditory ossicles?
to transfer and amplify vibrations from sound waves
228
what is the gel like structure that holds the tips of stereocilia on hair cells in the cochlear duct?
the tectorial membrane
229
what is the spiral organ composed of?
tectorial membrane
hair cells
basilar membrane
230
describe hair cells and primary sensory neurons during resting, excitation, and inhibition
* orientation of stereocilia
* ion channels
* neurotransmitter release
* action potential production
```
at rest:
*stereocilia are straight and upright
*about 10% of ion channels are open
*some neurotransmitters are being released
* action potentials are being produced
excitation:
*stereocilia are bent to the right
*more ion channels are open causing depolarization
*more neurotransmitters are released
*action potential frequency increases
inhibition:
*stereocilia are bent to the left
*ion channels are closed causing hyperpolarization
*no neurotransmitters are released
*action potential ceases
```
231
is the cochlear nerve transmitting action potentials when no sound is detected?
yes
232
what is the pathway of information related to sound starting at the hair cells
1) hair cells
2) cochlear nerve
3) olive in medulla
4) inferior colliculi in midbrain
* *some information travels to cerebellum**
5) medial geniculate nuclei in the thalamus
6) auditory cortex in temporal lobe
233
where is auditory information crossed over so that it can reach both sides of brain?
in the medulla
234
why does auditory information travel to the cerebellum?
to aid in the coordination of movement
235
describe the structure and function of the basilar membrane
the membrane is thick and stiff near the oval window and gradually gets more thin and flexible. the variable thickness allows for pitch discrimination.
236
what is pitch discrimination?
low frequency sounds are only able to distort parts of the basilar membrane that are more thin and flexible(toward the apex of cochlea) while higher pitch noises are able to distort the basilar membrane closer to the oval window where the membrane is more thick and stiff. each part of the basilar membrane deals with specific pitches
237
how does the brain detect loudness?
the frequency of action potentials transmitted by the cochlear nerve indicates the loudness
238
what is conductive hearing loss?
| what is sensorineural hearing loss?
conductive hearing loss occurs when sound waves do not reach the inner ear
sensorineural hearing loss occurs when sound waves are not processed correctly( damage to inner ear structures)
239
what is central deafness?
damage to auditory neural pathway
240
what are otoliths?
crystals that provide weight to the otolith membrane that covers hair cells in the vestibular aparatus
241
what does the utricle and saccule detect?
linear movement and position of head
242
what do semicircular canals in the vestibular apparatus detect?
rotational movement
* shaking head no
* tilting head
* shaking head yes
243
what is vertigo?
inappropriate perception of movement due to dysfunction of the vestibular system
244
what is vestibular nystagmus?
involuntary eye movement
245
what is the pathway of a peptide/protein hormone from synthesis to target cell?
1. mRNA binds to fixed ribosome on rough ER and inactive preprohormone is synthesized
2. the signal sequence is cut off in the rough ER turning it into an inactive prohormone
3. inactive Prohormone is packaged into a transport vesicle and is sent to the golgi apparatus
4. inactive prohormone travels through the golgi apparatus and is packaged into secretory vesicles
5. enzymes in the secretory vesicles remove peptide segments from the inactive prohormone rendering it an active hormone before it undergoes exocytosis
6. active hormone diffuses into the blood stream
7. once the active hormone arrives at the target cell it binds to receptors on the target cell
246
are peptide/protein hormones hydrophilic or hydrophobic?
hydrophilic
247
what type of receptor is used to receive peptide/protein hormones and what are the steps of the process?
GPCR receptors
PROCESS:
1) hormone binds to receptor
2) g proteins dissociate and alpha protein travels along plasma membrane to adenylate cyclase and activates it
3) ATP molecules interact with adenylate cyclase and are converted into cAMP
4) cAMP phosphorylates and activates Protein kinase which will lead to activation or inactivation of various enzymes
248
how is cellular activity associated with peptide/protein hormones stopped within a cell?
phosphodiesterase breaks down cAMP within the cell
249
what are the building blocks of steroid hormones and is it hydrophobic or hydrophilic?
cholesterol molecules are the building blocks of steroids and they are hydrophobic
250
where is cholesterol synthesized?
in the smooth ER
251
what are the pathways for these hormones?:
1) testosterone
2) estradiol
3) cortisol
5) aldosterone
testosterone- cholesterol > progesterone > testosterone
estradiol - cholesterol > progesterone > testosterone > estradiol
cortisol - cholesterol > progesterone > cortisol
aldosterone - cholesterol > progesterone > aldosterone
252
how do steroid hormones travel through the blood?
it binds to a transport protein until it needs to diffuse across a membrane?
253
how do steroid hormones travel in icf?
it binds to a protein called cytoplasmic receptor
254
how do steroid hormones diffuse across a plasma membrane or a nuclear membrane?
it separates from the transport protein and since it is hydrophobic and the inner layer of the plasma membrane is hydrophobic, it doesnt have a problem getting across the membrane
255
what do hormones bind to when they are in a nucleus?
nuclear receptors
256
what do steroid hormones do in the nucleus?
1) hormone/nuclear receptor complex binds to DNA and activates or represses one or more genes
2) activated genes create new mRNA that travel into the cytoplasm where it synthesizes new proteins
257
what is the difference between amino acid and peptide/protein hormones?
peptide hormone is made from a chain of at least 9 amino acids, protein hormones are made by chains made of at least 100 amino acids, and amino acid hormones are made by 1 amino acid
258
what amino acid are amino acid derived hormones made of?
tyrosine
259
which amino acid derived hormones can be made with tyrosine?
dopamine, norepinephrine, epinephrine, and thyroid hormones T3 and T4
260
where are the locations of receptors for these hormones?:
1) peptide/protein hormones
2) steroids
3) catacholamines
4) thyroid hormones
1) cell membrane
2) cytoplasm or nucleus
3) cell membrane
4) nucleus
261
what are the receptor-substrate response for these hormones?:
1) peptide/protein hormones
2) steroids
3) catecholamines
4) thyroid hormones
1) activate second messenger system
2) activation of genes for transcription and translation
3) activate second messenger system
4) activation of genes for transcription and translation
262
how are these hormones transported in the blood?:
1) peptide/protein hormones
2) steroids
3) catecholamines
4) thyroid hormones
1) dissolved in plasma
2) bound to carrier proteins
3) dissolved in plasma
4) bound to carrier proteins
263
what are the general target responses for these hormones?
1) peptide/protein hormones
2) steroids
3) catecholamines
4) thyroid hormones
1) modification of existing proteins and induction of new protein synthesis
2) induction of new protein synthesis
3) modification of existing proteins
4) induction of new protein synthesis
264
what are the neurohormones that are stored in the posterior pituitary gland?
oxytocin and vasopressin (ADH)
265
how are vasopressin and oxytocin made and transported to the posterior pituitary gland?
neuron cell bodies in the supraoptic and paraventricular nuclei in the hypothalamus produce these hormones and they are transported down the axons of the neurons via vesicles to the posterior pituitary gland. the vesicles are released in response to calcium ion influx of the axon terminal
266
how does the hypothalamus control the release of hormones from the anterior pituitary gland?
1) neurons synthesize trophic hormones and release them into the first capillary bed of the hypothalamic hypophyseal portal system.
2) portal veins carry trophic hormones to the anterior pituitary gland where they act on the endocrine cells of the anterior pituitary gland
3) endocrine cells of the anterior pituitary release their peptide hormones into the second set of capillaries for distribution to the rest of the body
267
what is the hormone pathway? (hypothalamus-thyroid)
1. the hypothalamus releases thyrotropin releasing hormone which travels to the anterior pituitary gland via portal system
2. in response to thyroptropin releasing hormone, the anterior pituitary releases thyroid stimulating hormone which travels to the thyroid gland
3. in response to thyroid stimulating hormone the thyroid gland produces thyroid hormones T3 and T4
4. T3 and T4 is released into the bloodstream and acts on many cells in the body
268
what is the hormone pathway? (hypothalamus-adrenal cortex)
1. hypothalamus releases corticotropin releasing hormone which travels to the anterior pituitary gland via the portal system
2. in response to corticotropin releasing hormone the anterior pituitary releases adrenocorticotropic hormone which travels to the adrenal cortex
3. in response to adrenocorticotropic hormone the adrenal gland releases cortisol into the blood stream
4. cortisol will circulate in the blood stream and act on many cells in the body
269
what is the hormone pathway? (hypothalamus-liver)
1. growth hormone releasing hormone is released from the hypothalamus and travels to the anterior pituitary gland via the portal system
2. in response to growth hormone stimulating hormone the anterior pituitary gland releases growth hormone which can take one of two pathways:
a) growth hormone can travel directly to many cells within the body via the blood stream
b) growth hormone can travel to the liver and stimulate the production and release of insulin like growth factors (IGFs) which will then travel to many cells within the body via the blood stream
270
what is somatostatin?
an inhibitory hormone that acts on the anterior pituitary gland and stops the release of growth hormone
271
what is the hormone pathway? (hypothalamus-endocrine cells of the gonads)
1) the hypothalamus releases gonadotropin releasing hormone which travels to the anterior pituitary via the portal system
2) in response to gonadotropin releasing hormone the anterior pituitary gland releases gonadotropins (follicle stimulating hormone and luteinizing hormone) into the blood stream where it travels to endocrine cells of the gonads
3) in response to the arrival of gonadotropins (luteinizing hormone and follicle stimulating hormone) the gonads release either androgens or estrogens and progesterone which travel to the non endocrine sex cells and many other cells of the body
272
describe the pathway of prolactin
prolactin is released from the anterior pituitary without a signal from the hypothalamus and travels to the breast to stimulate the production and release of milk. its inhibitory hormone is dopamine
273
what organs does negative feedback act on to stop the production of hormones?
either the hypothalamus or the anterior pituitary gland. usually the hypothalamus
274
what are the 3 layers of the adrenal cortex and what hormones do they produce?
(starting at the most superficial)
1) zona glomerulosa - aldosterone
2) zona fasciculata - glucocorticoids
3) zona reticularis - sex hormones
275
what category of adrenal hormone is aldosterone?
mineralocorticoid
276
what is the function of aldosterone?
it adjusts NA+ and K+ levels
277
what category of adrenal hormones is cortisol?
glucocorticoid
278
what is the function of cortisol?
to prevent hypoglycemia
279
describe the effects cortisol has on these target tissues:
1) immune
2) liver
3) muscle
4) adipose tissue
1) suppressed immune system(inhibits inflammatory response)
2) gluconeogensis
3) protein catabolism
4) lipolysis
280
what is cushings syndrome caused by?
hypercortisolism
281
what are 3characteristics of hypercortisolism?
1) loss of mass in limbs but an excess of fat buildup in the abdominal region
2) moon face or a loss of jaw line
3) hump behind neck
282
what is the difference between primary, secondary, and tertiary hormonal pathology?
primary pathology - something wrong with the endocrine gland
secondary pathology - something wrong with the anterior pituitary gland
tertiary pathology - something wrong with the hypothalamus
283
what does cortisol medication do to the hormonal pathway of cortisol?
negative feedback shuts down the production of cortisol starting with corticotropin releasing hormone which leads to a low level of adrenocorticotropin hormone and cortisol in the blood. when a patient stops taking this medication he/she needs to be tapered off to gradually regain natural cortisol production in the body
284
what is the difference between hypercortisolism and hypocortisolism?
hypercortisolism is excessive cortisol in the body
| hypocortisolism is a hyposecretion of ALL adrenal steroid hormones
285
what is hypocortisolism usually caused by?
addisons disease which is an autoimmune disease. hyperpigmentation of the skin and gums is a symptom of addisons disease
