Exam 2 Flashcards
(60 cards)
1
Q
antagonist
A
binds to a receptor and inhibits it
2
Q
agonist
A
binds to a receptor and activates it
3
Q
Central Nervous System
A
consists of brain and spinal cord. receive sensory information from the environment and send motor information
4
Q
Sensory
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picking up information from the receptors to do the sensing so it can send it to the central nervous system
5
Q
Motor
A
doing the action. doing the thing that the central nervous system says to do
6
Q
Frontal Lobe
A
prefrontal cortex: rational thinking, decision making, processing, conscious thought
7
Q
central sulcus
A
the valley
8
Q
the hill
A
the gyrus
9
Q
precentral gyrus
A
in the frontal lobe. called the Primary motor cortex is involved in movement control.
10
Q
Broca’s area
A
in the frontal lobe. speech production
11
Q
postcentral gyrus
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in Parietal Lobe. called the Primary sensory cortex. touch, pain, temperature
12
Q
Occipital Lobe
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coordinates our sense of vision
13
Q
Temporal Lobe
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processes hearing. auditory cortex.
14
Q
Wernicke’s area
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part of temporal lobe. understanding/comprehension of speech
15
Q
Cortex
A
the outside of the brain
16
Q
nociceptor
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a sensory receptor for painful stimuli
17
Q
Limbic System
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subconscious reactions. deeper structure in the brain.
18
Q
thalamus
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part of limbic. sensory integration. almost every single one of the senses routes through the thalamus. collects all of the sensory information and sends it to the appropriate place. olfaction is the only sense that bypasses.
19
Q
hypothalamus
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part of limbic. constantly monitoring everything. crucial for homeostasis. releases hormones. manager of the autonomic nervous system (deals with unconscious function)
20
Q
hippocampus
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part of limbic. responsible for long term memory
21
Q
amygdala
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part of limbic. emotions such as fear, anger. important in responding to out group members.
22
Q
spinal cord
A
when the peripheral nervous system is receiving sensory information, that information is sent to your spinal cord, comes in from the posterior area of the spinal cord, travel up to the brain, tells your brain the message, a decision is made and that travels back to the spinal cord to the anterior portion and goes out to the peripheral nervous system that performs the action
23
Q
Reflex Arc
A
when we don’t communicate with higher brain structures because it has to have a fast response. connection between a sensory neuron and a motor neuron thats going to bypass higher brain structures.
24
Q
The senses
A
Afferent division. determine whats going on in the environment and send to CNS
25
Signal transduction
the conversion of a stimulus into a chemical signal. An action potential must be triggered.
26
gustation and olfaction
signal transaction turning chemicals into action potential and neurotransmitter release. the 5 tastes are bitter, sweet, salty, sour, and umami. hearing is primarily processed in the temporal lobe and vision is processed in the occipital lobe.
27
hearing
what we are sensing is vibration. sound travels into the oracle of the ear into the ear canal. then it is going to his the tympanic membrane. that sends the vibration to 3 tiny bones in the middle ear called the ossicles. they amplify the vibrations so they can be picked up by the nervous system. it is sent to the cochlea which is a fluid filled chamber via the oval window. specialized receptors in the cochlea called hair cells (mechanoreceptors) which sense how that fluid is moving and transduce that into the electrical and chemical signals that the nervous system understands.
28
vision
phototransduction is the transduction of photons into action potential/neurotransmitter release. there are 2 types: rods which sense dim light and cones which sense color
29
rods
focuses on dim light. in darkness, sodium and potassium ion channels are open. the membrane potential ends up being about -40 mV which is above the threshold. this means that an action potential occurs; depolarization. because of this it is always releasing neurotransmitters.
in the light- photons break rhodopsin down into opsin and retinal. opsin inhibits sodium channels causing the inside to become more negative and re-polarize the membrane. this means neurotransmitters to stop being released. the amount of light is proportionately related to the amount of neurotransmitters being released.
30
rods recovery
in the dark when the photons start to go away then retinal is going to recombine with opsin to become rhodopsin so the opsin can no longer inhibit the sodium channels. sodium channels open again.
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cones
bright light and colors
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efferent vs afferent
Neurons that receive information from our sensory organs (e.g. eye, skin) and transmit this input to the central nervous system are called afferent neurons. Neurons that send impulses from the central nervous system to your limbs and organs are called efferent neurons.
afferent: sensory
efferent: motor
33
Motor- Efferent divided into which 2 branches
somatic (voluntary) and autonomic (involuntary)
34
autonomic broken down into which 2 divisions
sympathetic and parasympathetic. they are contrasting systems. as one increases the other decreases.
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parasympathetic
rest and digest. when you’re calm nothing is really going on. slow heart rate, increase digestion.
36
sympathetic
fight or flight. when you’re actively engaging in something. increasing heart rate, opening up airways, turning off digestion, pupils dilate.
37
autonomic pathways have 2 neurons involved
one starts in the central nervous system (preganglionic neuron) and the other communicates with whatever needs to do something (postganglionic neuron). in between both neurons is the area called the autonomic ganglion which is where the synapses occur.
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autonomic pathway steps
the preganglionic neuron is going to release acetylcholine which tells the next neuron to have an action potential so that you can communicate with your organ. there is a specific type of receptor for acetylcholine on the autonomic ganglion which is nicotinic receptor. they allow Na+ entry into postganglionic cells and create action potential.
postganglionic sympathetic neurons are going to release norepinephrine onto adrenergic receptors on the target cell which are linked to G proteins which activate second messenger pathways to cause whatever we want it to do.
postganglionic parasympathetic neurons release acetylcholine onto muscarinic receptors onto the target cell which are linked to G protein which activate a separate messenger pathway to create a cell response
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typical target tissues for autonomic pathway
smooth muscle (stomach, intestines), cardiac muscle, and glands.
40
the neuroeffector junction
the synapse between the postganglionic autonomic neuron and its target cells. autonomic postganglionic axons end with a series of swollen areas called varicosities which contain vesicles filled with neurotransmitters
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somatic motor neurons
only 1 neuron originating in the central nervous system and directly talking with the target tissue, in this case skeletal muscle. this motor neuron has lots of axon terminals that are going to talk to more than one muscle fiber.
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synapses
neuromuscular junction. the presynaptic axon (motor neuron) and the synaptic cleft and then the postsynaptic cell who’s membrane is called the motor end plate
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somatic nervous system
when acetylcholine is sent by the somatic motor neuron across the synapse its going to bind to nicotinic acetylcholine receptors on the skeletal muscle fiber and this binding causes the opening of the monovalent cation channel allowing sodium to come in and potassium potassium to go out causing depolarization of that skeletal muscle fiber
44
Skeletal muscle anatomy
cell membrane is the sarcolemma. muscle fibers same as muscle cells. involved in excitation reaction coupling: motor neuron, sarcolemma, sarcoplasmic reticulum. sarcomere: a structural and functional unit in skeletal muscle cells that contains 2 important proteins: myosin and actin where they overlap. actin crosses over the myosin it makes the sarcomere shorter which leads to a contraction. what connects the two is calcium.
45
T-tubules
shaped like a T. connect neuromuscular junction to other muscle fiber structures. The T-tubules going down into the muscle fiber because depolarization is something that happens at the membrane which allows it to be close to things in order to do work, would miss all of the structure that are deeper inside. Depolarization deeper in the skeletal muscle fibers is going to cause DHPR (voltage receptor) which is not a channel itself, to pop open the Ryanodine channel which carries calcium causing it to leave the smooth ER where it enters the cytoplasm. This process is called reaction coupling.
46
final steps of excitation contraction coupling
calcium binds to triponin. calcium troponin complex moves tropomyosin out of the way.
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Once calcium is present
actin and myosin overlap leading to contraction. The cycle consists of myosin binding to actin, pulling the actin inward, releasing it, and repeating as long as calcium and ATP are present.
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The Cross Bridge Cycle
1. ATP binds to myosin: it allows for myosin to get into a relaxed and ready position
2. hydrolysis of ATP (use water to break up ATP making it ADP and an inorganic phosphate) allows myosin to bind weakly to actin
3. the power stroke: when inorganic phosphate is released, myosin pulls the actin towards the M line (“pulling of the rope”)
3. ADP is released from the myosin head so that ATP can bind again and thus the cycle continues
the muscle relaxes by pumping the calcium back into the smooth ER. without the calcium, the muscle cannot be flexing. the rianodine channel is going to close because theres no depolarization and you have a calcium pump on the sarcoplasmic reticulum. its active transport, requires a pump, to get calcium back into the smooth ER
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types of skeletal muscle contraction
1. concentric contraction: the muscle shortens
2. eccentric contraction: the muscle lengthens. like a controlled release
3. isometric contraction: where its not moving
50
what increases the force of muscle contraction
large number of muscle fibers recruited, large muscle fibers, light frequency of stimulation, muscle and sarcomere stretched to slightly over 100% of resting length
51
Cardiovascular System: two different types of muscle
the heart (cardiac muscle), and blood vessels (smooth muscle)
52
cardiovascular does not require
nervous system innervation in order to contract because it has pace maker cells. NS does modify cardiac muscle activity via the autonomic nervous system
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cardiovascular has
sarcomeres: overlapping actin and myosin. indicate striations
54
cardiomyocytes are connected to each other by
gap junctions which is where the cells are connected but they have little pores in them so that ions can go from one cell directly into another cell (aka intercalated discs). important because ions are critical for changing membrane potential so in the heart in order to have a coordinated contraction you have the signal travel as quickly as possible.
55
pacemaker cells
have a spontaneous action potential that is rapidly spread to other cardiomyocytes through gap junctions. starts in the SA node which is where the pacemaker cells are located. it communicated to the AV node which communicated with the ventricles. so it travels throughout the entire muscle of the heart
56
cardiac action potential
voltage gated as sodium is traveling through the intercalated discs.
1. resting membrane potential. -70 mV
2. sodium channels open- depolarization occurs
3. sodium channels close, potassium channels open
4. L-type calcium channels open, allow calcium into the cell, which causes the plateau because they stay open longer
5. L-type calcium channels close and the potassium channels cause re-polarization
6. potassium channels close once they reach membrane potential
57
the benefits of having the L-type calcium channels
is that the refractory period ends at the same time as the contraction. This is important because once the contraction has ended and we have relaxation, we want to be able to have another contraction. Heart has to keep beating all the time.
L-type calcium channels also prevent continuous contraction. example: tetanus.
Calcium is also crucial for cross-bridge cycling.
58
excitation contraction coupling in cardiac muscle
it is called Calcium Induced Calcium Release. action potential starts and the L-type calcium channels opening, this allows calcium to go into the intracellular fluid. this calcium comes from the extracellular fluid which is the trigger for some also to come from the sarcoplasmic reticulum from inside the cardiac muscle. calcium is the activator for the ryanodine channels which are triggered by the calcium binding to it. So calcium coming from both sides. the calcium leaves the sarcoplasmic reticulum and signals contraction to occur via cross-bridge cycling.
in order for relaxation to occur calcium must be pumped back into the extracellular fluid and back into the sarcoplasmic reticulum using ATP.
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Smooth Muscle:
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blood vessels. some can be controlled by pacemaker cells others controlled by the autonomic nervous system.
no sarcomeres (no striations). cross-bridge cycling still occurs but organization is different.
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60
excitation contraction coupling in smooth muscle
calcium enters the cytoplasm from 2 sources. calcium is released from the sarcoplasmic reticulum but this occurs via second messenger cascade following depolarization
enters from extracellular via voltage and ligand gated channels.
contraction and relaxation:
1. calcium binds to protein called calmodulin
2. activates another protein called MLCK which has been waiting for its signal to do its job
3. MLCK phosphorylates the myosin in order to activate it
4. cross bridge cycling occurs
5. to stop it, calcium goes away and MLCP removes the phosphates from the myosin preventing the contraction from occurring
