study guide 3 improved Flashcards
(136 cards)
1
Q
What do synaptic vesicles do?
A
They release neurotransmitters at chemical synapses.
2
Q
How can synaptic vesicles release neurotransmitters
A
Through a process called exocytosis which is triggered by calcium ions
3
Q
What is a central synapse?
A
A connection between neurons in the central nervous system.
4
Q
is a central synapse the same as the NMJ?
A
Central synapses and the NMJ are not the same. Both are synapses but a central synapse is in the brain while the NMJ is where a motor neuron meets a muscle fiber.
5
Q
What is a bouton?
A
Boutons (buttons)= numerous presynaptic terminals.
6
Q
What molecules can be neurotransmitters?
A
Small molecules
- Acetycholine
- Adenosine triphosphate (ATP)
- Nitric oxide (NO)
Amines
Amino Acids
7
Q
What is an ionotropic receptor?
A
An ionotropic receptor is a ligand-gated, chemically gated, neurotransmitter-gated receptor with a built in ion channel
8
Q
What is a metabotropic receptor?
A
Membrane receptor that modulates cell activity by initiating metabolic steps. dont have a built in ion channel
9
Q
EPSP and IPSP
A
Inhibitory postsynaptic potential (IPSP)
Excitatory postsynaptic potential (EPSP)
10
Q
Excitatory cholinergic synapse
A
-AP depolarizes axon terminal, opens VGCC, Ca2+ enters and triggers release of ACh
-ACh diffuses across cleft, binds to postsynaptic receptors
- ACh receptor are ionotropic ligand gated ion channels that open and allow Na+ and K+ across the membrane
11
Q
Inhibitory GABA-ergic synapse
A
- Uses y-aminobutyric acid (GABA) as neurotransmitter
- GABA receptors are chloride channels
-Cl- current hyperpolarizes the postsynaptic membrane - Postsynaptic neuron inhibited, less likely to fire action potential
- chloride goes in
12
Q
- Are neurotransmitters inhibitory or excitatory? What determines if a neurotransmitter will
lead to inhibition or excitation. Are they always one or the other?
A
can be either, depends on the synapse, can be inhibitory at one and excitatory at another
13
Q
How do you end a signal sent from a presynaptic cell to a postsynaptic cell? What
happens to released neurotransmitters?
A
Presynaptic cell stops releasing neurotransmitter
The neurotransmitter already in the synapse is cleared
- diffusion: diffuses out/away from the cleft
-degradation: degraded by enzymes present w/in synaptic cleft (like AChE for ACh)
- reputake via specialized transporter protiens into presynaptic terminals
- uptake (via special transport protiens) into surround glial cells
14
Q
What are the modes of synaptic transmission?
A
Vesicular secretion
- Movement from the presynaptic to the postsynaptic cell
Retrograde
- Release of a lipid-soluble molecule from the postsynaptic cell.
Non-vesicular
- Release of water-soluble molecules through a transmembrane channel within the plasma membrane.
15
Q
Vesicular secretion
A
vesicles release cargo, the release is ca2+ triggered exocytosis. This is the first to be discovered and is the “classic” mode of vesicular secretion.
The movement is “orthograde,” which means the movement from presynaptic to postsynaptic cell.
16
Q
Retrograde
A
Release of a lipid-soluble molecule from the postsynaptic cell. Nitric Oxide (NO) released
17
Q
Non vesicular
A
a vesicle is not needed. Release of a water-soluble molecule through a transmembrane channel within the plasma membrane. Thought to be CALHM1 in type II taste receptor cells within taste buds.
18
Q
What did Santiago Ramon y Cajal do? and what is the black reaction
A
Santiago Ramon y Cajal discovered the synaptic cleft. Used a tissue staining method known as the Black Reaction.
19
Q
who created the black reaction?
A
The black reaction was created by Camillo golgi
20
Q
cells bodies in the cns vs pns
A
CNS: nucleus
PNS: Ganglion
21
Q
What is the central nervous system composed of? How is the peripheral nervous system different?
A
CNS: brain & spinal cord
PNS: sensory & motor
22
Q
neurons in the nervous system
A
around 1 trillion
23
Q
neuroglia cells
A
cells that support neurons in the nervous system
24
Q
How many neuroglia cells in the nervous sytem
A
About 10 trillion in the nervous system
25
Four types of neuroglia cells in the CNS
Oligodendrocytes, ependymal cells, microglia, and astrocytes.
ollie puts an epipen in his leg and he mutates so astroctyes come from his hands
26
Two types of neuroglia cells in the PNS
Schwann cells and satellite cells
27
Universal properties of neurons
Excitability (irritability)
Respond to environmental changes (stimuli)
Conductivity: Produce electrical signals that travel along nerve fibers (axons) to reach other cells at distant locations.
Secretion: Nerve fiber endings (axon terminals) release chemical neurotransmitters that influence other cells
28
dendrites
multiple branches that come off the soma, primary site for receiving signals from other neurons.
29
soma (cell body)
has a centrally located nucleus with large nucleolus. Contains mitochondria, lysosomes, Golgi complex, rough ER, inclusions, and cytoskeleton like other cells. No centrioles.
30
axon (nerve fiber)
specialized for rapid conduction of electrical signals, only one axon per neuron, Originates at the axon hillock.
31
axon terminals
swellings that form contact points (synapses) with other cells. Contain synaptic vesicles full of neurotransmitters.
32
myelin sheath
insulating layer surrounding some axons. Formed by glial cells.
33
Multipolar neurons
One axon and multiple dendrites (most neurons in the CNS)
34
Bipolar neuron
One axon and one dendrite (olfactory cells, retina, inner ear, taste buds)
PNS
35
Unipolar neuron
a single process leading away from soma that splits into axon and dendrite (sensory cells from skin and organs to the spinal cord)
PNS
36
Where do you find bipolar neurons
You’d find bipolar neurons in olfactory cells, retina, inner ear, or taste buds.
PNS
37
Where do you find anaxonic neurons
many dendrites but no axon (retina, brain, adrenal gland.)
38
What is gray matter?
Gray matter contains cell bodies, dendrites, and synapses. Darker color due to very little myelin present in the tissue. Forms surface layer (cortex) over cerebrum and cerebellum. Forms nuclei deep within the brain.
39
White matter
White matter: Bundles of axons. White color from lots of myelin. Called “tracts” in the CNS and “nerves” in the PNS. Deep to cortical gray matter in the brain. Superficial to gray matter in the spinal cord.
40
What does the nervous system develop from in the embryo (which tissue layer)?
The nervous system develops from the ectoderm (outermost tissue layer of the embryo)
41
How does the neural tube form
1. Dorsal midline of embryo thickens to form neural plate
2. Neural plate sinks and its edges thicken.
3. Forms neural groove with a raised neural fold on each side.
4. Neural folds fuse, creating a hollow neural tube by day 26.
42
How much blood flow goes to the brain?
Estimated 15% of cardiac output
43
Why does the brain need so much blood
It requires a constant supply of blood to deliver oxygen and nutrients to its cells and to support its high metabolic demand.
44
The brain is protected by the skull, membranes, and fluid. What are these membranes?
From outermost to innermost
Dura mater
Arachnoid mater
Pia mater
45
What is the fluid? What is the benefit to having our brain surrounded by fluid?
Cerebrospinal fluid (CSF). It protects and nourishes the brain & spinal cord.
46
What is the choroid plexus?
structues in the ventricals made of ependymal cells that make CSF
47
What does the choroid plexus do
create cerebrospinal fluid.
48
What is the cerebrum?
The cerebrum is the largest, most conspicuous part of the human brain. It’s the seat of sensory perception, memory, thought, judgment, and voluntary motor actions.
49
Outer layer of the cerebrum is called? What color is it
The outer layer, the cerebral cortex, is made up of grey matter.
50
Frontal lobe
- Voluntary motor control of skeletal muscles; personality; high intellectual processes; verbal communication.
51
Parietal lobe
- Cutaneous and muscular sensations, understanding speech and formulating words to express thoughts and emotions, interpretation of textures and shapes.
52
Occipital lobe
- Integration of movements in focusing the eye; correlation of visual images with previous visual experiences and other sensory stimuli.
53
Temporal lobe
- Memory; sensory and visceral integration.
54
What is the primary motor cortex?
The motor area that controls voluntary skeletal muscles is known as the primary motor cortex.
55
What is the motor circuit?
The motor circuit is formed by interconnections between the motor cortex, the basal nuclei, and other brain regions.
56
GABA in the motor circuit
GABA is usually used to calm down neurons and make them less excitable.
57
What is lateralization?
Lateralization refers to the fact that the right and left cerebral hemispheres have different functions.
58
Which hemisphere deals speech? What about spatial concepts?
Left: speech
Right: Spatial concepts
59
What is the corpus callosum?
Corpus callosum: the myelinated axon tracts connecting the two hemispheres
60
Why would anyone want a split brain?
They would have a corpus callosotomy has been used to reduce seizures in medically refractory epilepsy.
61
What two important areas play a role in speech?
Wernicke’s area and Broca’s area.
62
What is it called when you have speech
deficits?
A speech deficit is called aphasias.
63
How is speech impacted when Broca’s area is damaged?
When Broca’s area is damaged words may be uttered very slowly and poorly articulated.
64
How is speech impacted when wernickes area is damaged?
When Wernicke's area is damaged the person has difficulty with understanding language and forming meaningful sentences.
65
Where is the limbic system,
The limbic system is in the temporal lobe.
66
What is part of the limbic system?
the amygdala and hippocampus.
67
what does the limbic system do?
limbic system controls emotions.
68
What does the hippocampus do?
Learning and memory
69
What is the hypothalamus?
Controls, temperature, water, hunger, emotional, sexual response, memory, and sleep.
70
What does the hippocampus resemble (what is it named after)?
seahorse
71
What is the physical basis of memory?
Is a pathway through the brain called a memory trace or engram.
72
What is synaptic plasticity?
Ability of synapses to change
73
synaptic potentiation
Process of making transmission easier
74
Some memories last-----
short time periods and are not retained but others can last long periods of tine due to molecular changes
75
What are dendritic spines
Tiny buds on dendrites which are the location of many synapses
76
pyramidal cells?
Large neurons of primary motor cortex
77
Why is long-term memory considered activity dependent?
Because it requires protein and RNA synthesis & synaptic changes
(I have no idea)
you have to use it to reinforce the pathways. use the AMPA receptors to get enough sodium in to move the magnesium out of the NMDA receptor mouth which can in turn create more AMPA receptors on the postsynaptic cell to move even more magnezium in the NMDA mouthes
78
NMDA receptor
a receptor site on the hippocampus that influences the flow of information between the neurons by controlling the initiation of long-term potentiation.
the one with the magnezium blocking the mouth
79
AMPA receptor
ionotropic glutamate receptor that controls a sodium channel; stimulated by AMPA.
80
What role does mg2+ play
NMDA receptors at the same synapse remain blocked by extracellular mg2+ until postsynaptic membrane depolarization occurs.
yeah don't know
81
membrane depolarization occurs.
* How does calcium get into the post-synaptic cell? What does it do?
Na+ gets in through the AMPA receptors. Once enough Na+ gets in, Mg2+ is pushed out of the mouth of the NMDA receptor which allows calcium in. Ca2+ influx into postsynaptic neuron activates Ca2+ activated proteins which triggers the insertion of additional AMPA receptors, which make it even easier to open NMDA receptors. Memories get easier to remember the more you remember them!!
82
How does a cell’s sensitivity to glutamate get changed with use? What does nitric oxide do?
When NMDA receptors bind glutamate and receive tetanic stimuli, they allow ca2+ to enter the cell.
Nitric oxide is a retrograde neurotransmitter.
83
What organisms have circadian rhythms?
Circadian rhythms have been observed in: animals, plants, fungi, and cyanobacteria.
84
Do all animals have the same day/night cycle
as humans?
Not all animals have the same day-night cycle.
85
Why even have a day/night cycle?
Circadian rhythms enable our bodies to anticipate challenge to homeostasis. This is known as “anticipatory homeostasis”
86
Circadian rhythms are considered endogenous (built-in) but they can be entrained. What
does that mean?
They can be synchronized by the cues in the environment.
87
What is the most important environmental cue we use for sleep?
Light is the most important environmental cue in entraining our circadian rhythms. It is totally reliable.
88
Why do we feel so bad when we have jet lag?
Our internal body clock is out of sync with the new time zone.
89
What wavelengths of light are more energetic?
The shorter the wavelength the more energetic than light having longer wavelengths.
(violet and blue more energetic than red)
90
What are iPRGs, where are they found, and what do they detect?
Intrinsically photosensitive retinal ganglion neurons (iPRGs) in the retina.
detect blue light (wavelength 446-477nm)
91
What is melanopsin? Is it different from melatonin?
Melanopsin: a photo-sensitive G protein couples receptor (GPCR) that is similar to rhodopsin used for vision.
not the same as melatonin
92
iPRGs project their axons where? Why does this information need to get there?
project their axons into the Suprachiasmatic Nucleus (SCN) using the Retino-hypothalamic Tracts. Provide visual stimuli (light) to the Master Clock (hypothalamus)
93
Where is the suprachiasmatic nucleus (SCN)? Does it play a role in vision?
Located in the anterior part of the hypothalamus above the optic chiasm. Doesnt deal much with light but does do Circadian Rhythm stuff
94
Can you explain how information from the SCN gets to the pineal gland?
SCN indirectly innervates the Pineal gland (melatonin secretor)
Meletonin is only secreted when NO BLUE LIGHT is hitting the retinas (the IPRG's sense light in retina, send info along RHT to SCN. SCN indirectly innvervates the pineal gland through the Superior Cervical Ganglia (SCG) which run from the SCN down the neck, then back up to the pineal gland)
95
What is the Retino-Hypothalamic Tract (RHT)? Is this the same thing as the optic tracts?
A neural pathway that carries light information directly from the retina to the suprachiasmatic nucleus in the hypothalamus. It is not the same thing as the optic tracts.
96
nucleus in the hypothalamus. It is not the same thing as the optic tracts.
* Why is the SCN called the “Master Clock”?
Because it coordinates circadian rhythms.
97
* The superior cervical ganglia (SCG) provide sympathetic innervation to the pineal gland.
Where is the SCG found?
paired ganglia in the neck. Runs from SCN down the neck then back up to pineal gland. You would find it located ant. to the prevertebral muscles (scalene ant. med. and post.) and behind the carotid sheath (which I'm pretty sure is the thing your jugulars are in so just behind those guys)
98
* Where is the pineal gland found? What does it look like (what is it named for)?
Located in the roof of the 3rd ventricle of the brain. Also known as the epiphysis. Like a pinecone.
99
What happens to the pineal gland as we age? What does it produce?
After age 7 it shrinks. Down 75% by the end of puberty. Produces melatonin.
100
Why is melatonin considered the “hormone of darkness”?
It is secreted when there is NO blue light hitting the retinas.
101
Around what time of the night is melatonin at its peak level of secretion?
Around 3:00 am.
102
Why can a large meal (like thanksgiving dinner) make us sleepy?
Dietary proteins contain amino acid L-tryptophan. Melatonin is an indoleamine hormone synthesized from L-tryptophan. more dietary proteins=more L-tryptophan=more melatonin
103
We discussed S.A.D., and Night-shift work. What causes S.A.D.?
S.A.D is caused by secretion of melatonin during the day (this is caused by staying indoors).
104
Why is night-shift
work so hard for people to do?
Night shift work is difficult because they need complete darkness during the day and exposure to sufficiently bright blue light during the night which is not achieved.
105
Which animals are known to deprive
themselves of sleep?
Humans are the only animals who deliberately deprive themselves of sleep.
106
What are some effects of sleep deprivation?
decreased life span and increased likelihood of developing Alzheimer’s.
107
Is sleep a passive or active process? Why?
Sleep is an active process because it requires energy and important processes occur during sleep.
108
What are the two main types of sleep?
REM sleep: rapid eye movement or dreaming sleep
Non-REM sleep: resting sleep, slow wave sleep, and deep sleep.
109
How long is a sleep cycle?
Around 90 minutes.
110
What are the stages that occur during the sleep cycle?
1: Transition from wake to sleep. theta waves
2: Light sleep. theta waves with spindles
3: Transition to deep sleep- delta waves
4:Deep sleep- delta waves.
111
How many cycles do we normally have a night? Is this why we say we need 7-9 hours of sleep
each night?
We cycle between REM and non-REM about five times a night if we sleep enough. probably
112
In the EEG, if you recorded an alpha rhythm what would you expect that person to be
doing? What about beta rhythm?
Alpha: drowsy or meditating.
Beta: Alert.
113
What is seen in EEG recordings of people sleeping? Are they alpha or beta rhythms?
theta, theta w spindles, delta waves
114
What are the four stages of Non-REM sleep
1. Transition from wake to sleep, very light sleep
2. Light sleep
3. Transition to deep sleep
4. Deep sleep
115
What is happening during REM sleep?
REM sleep is said to be “sort of like being awake”
116
What is paradoxical sleep? Why is it called that?
REM sleep is also called paradoxical sleep because the EEG looks like the person might be awake but they are actually asleep.
117
The amount of time spent in REM sleep decreases with age. Why is this?
Spontaneous arousals increase in older adults.
Older adults go to sleep/wake up earlier due to advances in a normal circadian sleep cycle.
More respiratory disorders that impact sleep occur as you age.
118
Why even have
REM sleep?
We have REM sleep because it “allows us to practice dangerous activities without actually endangering ourselves” That sounds made up as hell
119
What does our sleep look like throughout the night?
alert, drowsy, stage 1, 2, 3, 4, 3, 2, 1, rem
120
What is the sleep progression?
Going through sleep
121
How often do we get a chance to get into that very deep sleep?
Not very often probably
122
Why is deep sleep needed?
Rest and repair of the body.
123
Why do we need sleep? How long can you go without sleep?
11 days with no sleep
We need it because it facilitates the consolidation of short-term memories into long-term memories.
124
Why can’t you make up sleep on the weekend?
It can help with improving how you feel, but you don’t get the time to repair your body every day like you need.
125
Do teenagers actually need that much sleep?
Teenagers need a lot of sleep because circadian rhythms can change.
126
What is sleep paralysis? Is it harmful?
During REM your skeletal muscles are paralyzed. Sometimes people wake up but they cant move for a few seconds or minutes. Scary but not dangerous.
127
What is sleep apnea? Why does it cause disrupted sleep?
period stopping of breathing during sleep. 2 types
* central sleep apnea- respiratory control center in the medulla stops sending APs to diaphragm
* Obstructive sleep apnea- physical narrowing or collapse of upper airways
brain freaks out when not enough O2, sets off alarms which wake you up
128
which apnea is due to the physical narrowing of the upper airway
Obstructive sleep apnea is a physical narrowing or collapse of the upper airways. Can be as a consequence of obesity, loss of muscle tone during aging, or decreased airway related muscle activity during REM sleep.
129
treatment of sleep apnea
Surgical treatment for airway obstruction (e.g., remove some adipose tissue)
CPAP (Continuous Positive Airways Pressure) mask helps keep airways open during sleep.
130
* What is narcolepsy?
The person has an uncontrollable, undeniable need to fall asleep during daytime activities.
131
The person has an uncontrollable, undeniable need to fall asleep during daytime activities.
What do we think might cause narcolepsy?
May be caused by an autoimmune attack or orexin/hypocretin-secreting neurons in the hypothalamus.
132
What is sleep hygiene?
Healthy sleep habits and getting good sleep.
133
N-Rem sleep stage one stuff to know
Transition from wake to sleep
- first ~10 mins
- HR, breathing, brainwaves, eye movement slows down. muscles relax
- easy to wake someone, but they'll be disoriented bc they didn't even realize they were falling asleep
- theta waves
134
N-rem stage 2 must knows!!!
Light sleep
- next ~20 minutes
- HR, breathing slows more, muscles relax more, body temp drops. eye movements stop
- not as easy to wake someone as in stage one. wont be disoriented if woken here
- theta waves w/ spindles
135
N-rem stage 3
Transition to deep sleep
-HR and breathing at lowest levels, muscles stay relaxed
- **delta waves** start to show up
- this is where bedwetting and sleepwalking would happen
136
N-rem stage 4 (final)
Deep sleep
- body repairs and regrows tissue, strengthens immune system, builds bone/muscle
- hard to wake someone from this stage
- if you wake up here, you'll be groggy and disoriented
