Exam 1 Flashcards
(166 cards)
1
Q
Explain the rationale fro studying physiology
A
Knowing the function of underlying mechanisms and how they are integrated into the human body can allow us to become better well rounded clinicians and it provides overlap of other topics such as pharmacology, biochem, immunology etc.
2
Q
Describe homeostasis and provide examples
A
Homeostasis is a dynamic and responsive ability of the body to respond to stimuli and internal/external changes that allow regulation. BP, kidney intake and release of water, etc.
3
Q
What is a negative feedback loop, give an example
A
A response loop that can be shut off by counteracting the stimulus causing it. Example—control of blood glucose levels.
4
Q
What is a positive feedback loop, give examples.
A
A positive feedback loops is a response loop that reinforces the stimulus, sending the variable farther from set point. Ex—blood clotting, child birth, menstrual cycle, digestion, nerve signaling.
5
Q
What is a feed forward loop? Give example
A
A feed forward loop is a response that helps prepare the body for a stimulus. The salivation response that happens when you see/smell/think of food.
6
Q
What are the components of a response loop
A
Stimulus-change in internal environment
Sensor- detects environmental change
Input- afferent signal sent to integrating center
Integrating center- receives input signal
Output- efferent signal a message that is sent out
Target- cells, tissues, or organs that receive efferent signal for change
Response- change occurs
7
Q
Where it cortisol made
A
The adrenal glands
8
Q
What is cortisol and what does it do
A
Hormone that increases blood glucose, regulates BP, anti inflammatory response.
9
Q
How does cortisol provide homeostasis
A
It uses negative feedback loops to counter stimuli causing change
10
Q
How is cortisol related to corticosteroid-based medications and why are corticosteroids prescribed
A
Corticosteroids closely mimic cortisol and they are prescribed to people with inflammatory diseases
11
Q
Is it better to have dental surgery while your body levels of cortisol are high or low
A
When cortisol is low and there is less stress. Cortisol decreases in the evening when preparing for bed.
12
Q
What is the difference between osmolarity and tonicity
A
Osmolarity is a measurement of of osmotic pressure (osmol/L) and tonicity is a behavioral/functional term that is used to describe what a solution would do to a cells volume
13
Q
If a cells volume shrinks, the ECF is?
A
Hypertonic and fluid leaves
14
Q
If a cells volume swells, the ECF is?
A
Hypotonic and water enters the cell
15
Q
If there is no change to a cells volume the ECF is?
A
Isotonic
16
Q
Isosmotic
A
Same number of particles/electrolytes in solutions
17
Q
Hyperosmotic
A
One solution has more electrolytes that the other
18
Q
Hyposmotic
A
One solution has less electrolytes than the other
19
Q
Why Is the osmolarity of a solution not an accurate predictor of its tonicity
A
Because the cell isn’t permeable to all particles and electrolytes
20
Q
What electrolytes easily penetrate the cell membrane
A
Glucose/dextrose
21
Q
What will happen to the tonicity of your blood plasma if you drink excessive amounts of “pure” water (no electrolytes)
A
Blood plasma becomes hypotonic
22
Q
If a solution is .9% saline what is the osmolarity and tonicity
A
Isosmotic and isotonic
23
Q
If a solution is 5% dextrose in .9% saline (D5) what will the osmolarity and tonicity be?
A
Hyperosmotic and isotonic
24
Q
If a solution is 5% dextrose in water (D5W) what will the osmolarity and tonicity be?
A
Isosmotic and hypotonic
25
Ina .45% saline solution (half-normal saline) what will happen to the osmolarity and tonicity?
Hyposmotic and hypotonic
26
In a 5% dextrose in .45% saline (D5 half normal saline) solution what will the osmolarity and tonicity be?
Hyperosmotic and hypotonic
27
If a cell has a higher intracellular fluid concentration of nonpermeable particles/electrolytes than the surrounding extracellular fluid, which way will fluid move? What is the ECF tonicity?
Fluid will move in. The ECF is hypotonic relative to ICF
28
If a cell has a LOWER ICF concentration of non permeable particles/electrolytes than the surrounding ECF, which way will fluid move? What is the ECF tonicity?
Fluid will move out. The ECF is hypertonic relative to the ICF
29
What are the primary divisions of the nervous system
CNS and PNS
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What are the two basic categories of nervous system cells and their functions
Neurons- transmit signals
Glial Cells- support cells. They do transmit signals but they do not depolarize
31
What is the difference between a neuron and a nerve
A neuron is a single cell and a nerve is a compilation of neurons.
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What are components of the synaptic cleft
Presynaptic axon terminal and postsynaptic dendrite
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Where is a signal received from a neuron
Dendrite
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Synapse
The region where an axon terminal communicates with its postsynaptic target cell
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Resting potential
The difference in electrical charge between the extra and intracellular sides of the neuron membrane. When an axon is not firing. The membrane polarization remains around -70mV
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How is resting potential created
Extra/intracellular K+ concentration gradient, cell membrane permeability to K+, Na+, and Cl-. Osmotic pressure.
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How does resting potential occur
Na/K pump carrier proteins move large number of Na out of cell creating the + extracellular charge. Simultaneously the protein moves K+ into the cell cytoplasm. Because more Na is moved out than K in the becomes positive on the outside and negative on the inside
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How are nerve impulses transmitted?
Action potentials
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Action potential
Movement of ions across the neurons membrane resulting in rapid depolarization, followed by a repolarization, then a brief hyperpolarization (greater than -70mV), and then a return to RMP.
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What is the threshold level for depolarization to occur
-55mV
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Steps of action potential
1)depolarizing stimulus brings RMP to -55mV
2)voltage gated Na+ and K+ channels begin to open
3)rapid Na+ entry depolarizes cell
4)Na+ channels close and slow gated K+ channels open
5)K+ moves from the ICF to ECF
6)K+ channels remain open and additional K+ leaves the cell causing it to hyperpolarize
7)voltages gated K+ channels close, less K+ leaks out of cell
8)cell returns to resting ion permeability and RMP
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Absolute refractory period
Membrane can’t depolarize again or receive a stimulus (during hyperpolarization)
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Relative refractory period
Cell can depolarize but b/c of hyperpolarization stimulus needs to be stronger in order for cell to reach threshold.
44
The resting potential of peripheral and central nervous system neurons can and will vary (I.e. their excitability levels will fluctuate) T/F
True. One example is variability from day to day in pain sensitivity
45
In action potential conduction why does size matter
The larger the neuron the quicker the transmission speed
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Saltatory conduction
The ability of the signal to leap in a neuron because of the myelin insulated segments. Sodium channel opening only occurs periodically at the uninsulated spots (nodes of ranvier)
47
What area of communication between neurons will be most affected by drugs.
The activity in the synaptic cleft
48
Two types of synapses
Chemical or electrical
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Electrical synapse
Consists of a direct physical connection (gap junction) between two neurons which allows ions to flow from one to the next.
50
What synapse is the fastest form of communication
Electrical
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Groups of neurons connected by electrical synapses fire altogether in a synchronized fashion T/F
True
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Chemical synapses
A neuron with a presynaptic ending that contains neurotransmitter filled vesicles meets with a post synaptic neuron ending that contains receptors.
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Excitatory post synaptic potential
When a neurotransmitter of a presynaptic cell makes the postsynaptic neuron more likely to reach an AP
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Inhibitory postsynaptic potential
When the neurotransmitter of the presynaptic cell makes the post synaptic cell les likely to reach an AP
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Neuroplasticity
The variation of neuron signaling intensity due to the amount of neuro transmitter released and the number of receptors available.
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Temporal summation
Sensory summation that involves the addition of single stimuli over a short period of time. A single presynaptic neuron is responsible for generating the AP by generating subthresholds over a period of time. Less efficient process due to time it takes to generate AP
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Spatial Summation
Sensory stimulation that involves stimulation of several spatially separated neurons at the same time. Multiple presynaptic neurons are responsible for generating the AP and generating subthresholds. More efficient
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Where does the integration of EPSP’s and IPSP’s at an individual synapse occur
Axon hillock
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What determines the frequency of action potentials carried by the axon
Level and Duration of depolarization at the axon hillock
60
What is a divergent synapse pathway and give an example
When one presynaptic neuron branches to affect a larger number of postsynaptic neurons. Pain quality and intensity is interpreted within the CNS when a sensory signal reaches the brain and interconnect with MANY different areas in addition to the sensory homonculus. Or reflex when you touch something hot.
61
What is convergent synapse pathway and give n example
Many presynaptic neurons converge to influence a smaller number of postsynaptic neurons. Part of the reason referred pain occurs is due to multiple primary sensory neurons converging on a single ascending tract.
62
Two classifications of neurotransmitter receptor
Ionotropic and G-coupled receptors
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Ionotropic receptor
Ligand activated ion channels. These integral carrier proteins span these postsynaptic cell membrane and respond to binding a specific neurotransmitter known as a ligand or molecule/ion.
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What happens to Ionotropic receptors when a neurotransmitter binds to them
They change shape that creates a small channel opening that only allows a specific ion to flow through
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G protein coupled receptor
Also known as metabotropic receptors that are secondary signaling receptors.
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How does a G-coupled receptor work
Neurotransmitters bind to receptor triggering a g-protein pathway. G protein activates one or more other molecules known as secondary messengers. This can open or close channels. Secondary messengers can travel throughout the cell and create a wider range of responses than Ionotropic. Is slower and longer acting (sometimes) than Ionotropic
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endocannabinoids
Neurotransmitters that do not require a cell membrane receptor.
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Gasotransmitters
Soluble gasses that aren’t stored in a synaptic vesicle and diffuse directly through the cell membrane and act directly on molecules inside cell
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Norepinephrine
GPCR, ANS and CNS. Alertness and arousal. Excitatory and inhibitory functions
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Dopamine
GPCR, CNS. Primarily inhibitory and influences movement, learning, attention and emotion. Reward activity/motivation.
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Serotonin
Ionotropic and GPCR. CNS. Primarily inhibitory but regulates anxiety, appetite, mood, sleep cycle and body temp. Involved in circadian rythmicity and neuroendocrine function.
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Histamine
GPCR, CNS. Primarily excitatory. Increases wakefulness, stomach acid production, and itchiness, decreases hunger.
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GABA
Ionotropic and GPCR. CNS. Major inhibitory functions like decrease of muscle tone and anxiety, increases relaxation and sedation. Improves focus
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Glutamate
Ionotropic and GPCR. CNS. Major excitatory functions and involved with learning and memory
75
“Work” performed by the body specifically by contraction
Pumping blood, moving food through digestive tract, moving the body, absorbing shock and distributing loads.
76
What percentage of the total body weight that is muscle
40-50%
77
How much skeletal muscle mass is lost between ages of 30-50. And then by age 80
An estimated 10%. 40% by 80
78
Three types of muscular tissue
Skeletal, cardiac, smooth
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Skeletal muscle
Attaches to bone, skin or fascia. Striated with light and dark bands visible microscopically. Voluntary control of contraction and relaxation. Strong and quick.
80
Cardiac muscle
Striated in appearance. Involuntary control. Autorythmic because of built in pacemaker. Strong and quick.
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Smooth muscle
Nonstriated in appearance, involuntary control, strong in general but slow in most cases.
82
Which type of muscle store and move substance
Cardiac, smooth, and skeletal (sphincters, venous and lymph flow)
83
Example of involuntary skeletal muscle contraction
Shivering
84
What type of muscle produce heat
Skeletal muscles
85
Contractility
Ability to develop tension in response to a chemical and or electrical stimulus. This enables movement of structures to which the muscles are attached.
86
Electrical excitability
Like a neuron, muscle can conduct or transmit electrical impulses.
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Extensibility
Ability to stretch
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Elasticity
Ability to return to normal resting length. Retractility or recoil.
89
Tenosynovitis/tendonitis
Inflammation due to overuse or strain.
90
Strains
Contractile tissue injuries
91
Wear do tears most often occur
Myotendinous junction
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What is tendinitis or teninopathy
Tendon is abnormal and can’t handle stress. Chronic degenerative changes in the tissue w out inflammation
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Sarcolemma
Muscle fiber/cell membrane
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Endomysium
Surrounds the individual muscle fibers and insulates the individual cells form one another. Rich in capillaries.
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Perimysium
Ensheathes muscle fiber cells to form fascicles (bundles of muscle fibers). Penetrated by neurovascular bundles
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Epimysium
Wraps around the entire gross structure of a muscle (bundles of fascicles). Send septa inward (contains neurovascular bundles)
97
“Bundles of bundles”
That each subsequent layer of muscle connective tissue is tougher and thicker than the previous one.
98
Are endomysium and sarcolemma the same?
NO. Sarcolemma is the cell membrane. Endomysium covers outside of muscle cell.
99
What are the pros and cons of a neurovascular bundle
Efficiency is pro. But if the area gets damage both structures are at risk.
100
Somatic motor neurons
Nerve cells within the peripheral nerve found in the neurovascular bundle that connect the nervous system to the muscle cell
101
Myogenesis
Multiple mesodermal stem cells fusing together to form a muscle fiber in utero.
102
What cells remain to help with trauma in skeletal muscle
Myoblasts (satellite cells)
103
Myofibril
Structural and functional subunit of a muscle fiber. Composed of organized bundles of myofilaments that extend the entire length of the cell.
104
Sarcoplasmic reticulum
Fluid filled system of membranous sacs (sER) encircling each myofibril within the muscle fiber. Stores Ca2+ until needed.
105
Transverse tubules
Invaginations of sarcolemma into the cell that rapidly convey action potentials to all myofibrils inside the muscle fiber.
106
What fluid is in the T tubules
Extracellular
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Basic contractile component of a myofibril
Sarcomere
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What happens when a muscle contraction occurs (to bands and zones)
Z discs-move closer together
I bands- shrink
H zone- narrows
A band- does not change
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What proteins make up a myofibril
Contractile-actin and myosin
Regulatory- tropomyosin and troponin
Structural- titi, nebulin, alpha actin, myomesin, dystrophin
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Titin
Anchors thick filaments to Z line, its elasticity prevents excessive stretch of sarcomere/helps sarcomere return to resting length.
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Nebulin
Aligns thin filaments
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Alpha actin
Bundles thin filaments into parallel arrays and anchors them at Z line
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Myosin
Holds thick filaments in place at M-line
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Dystrophin
Absence is associated with ms cell death due to membrane ruptures—resulting in progressive weakness (muscular dystrophy)
115
List components of a muscle from smallest to largest
Sarcomere, myofibril, fiber, fascicle.
116
When a joint is immobilized for healing what do you think happens to the microstructure of those muscles?
Function decreases due to atrophy and stability decreases.
117
The NMJ consists of
Synapse, synaptic cleft, neurotransmitter, axon terminal (synaptic end bulb, synaptic vesicles, ACh), motor end plate
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One neuron innervates multiple muscle fibers. T/F
T. The number 0n muscle fibers interacted varies based on need for fine motor control.
119
Steps of nerve impulse at NMJ
1-release of ACh
2-opening of ACh gated sodium channels
3-production of muscle cell AP (influx Na+ an other ions from ECF to ICF)
4-closing of ACh gated channels (Na+ low and K+ high) ACh is broken down by acetylcholinesterase.
ACh has to be removed for contraction to end
120
Difference between myasthenia gravis and Bell’s palsy
MG is an autoimmune disease that causes progressive damage to the NMJ causing early on muscle fatigue and progressive weakness and muscle atrophy (ACh can’t bind or be released) Bell’s palsy is compression of facial nerve which impairs the ability of nerve to propagate an AP. ACh can’t get past compression to cause AP but once compression resolves it can.
121
Botulinum
“Miracle poison” that blocks ACh release form efferent motor neuron synaptic end bulb this preventing muscle contraction.
122
How many contractions can occur from ATP storage in a muscle cell
5-8
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What is a back up energy source to ATP
Phosphocreatine. Contains high energy phosphate bonds and transfers phosphate to ADP via creatine kinase enzyme
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How many ATP does glycolysis produce
About 30
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How many ATP does anaerobic glycolysis produce
About 2
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What is ATP required for
1-cross bridge formation and release (myofilament sliding)
2-active pump of calcium ions from sarcoplasm back into SR
3-sodium-potassium pump to restore muscle fiber membrane potential.
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Type I muscle fibers
Slow oxidative or “slow twitch” red muscle fibers. High resistance to fatigue, high # mitochondria, aerobic respiration. Slow use of ATP, red in color and low force production.
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Type II A muscle fibers
Fast oxidative-glycolytic (FOG) or “intermediate twitch”. Pinkish in color moderate # mitochondria and resistance to fatigue. Anaerobic and aerobic respiration. Fast Rae of ATP use, fast contraction velocity and high force production.
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Type II X
Fast glycolysis (FG) or fast twitch fibers. Low number mito, low resistance to fatigue. Anaerobic respiration. Fastest rate of ATP use and contraction velocity. High force production and white in color
130
Your patient has a genetic disorder that causes their skeletal muscle mitochondria to be under produced and or abnormal. Which of the following problems would you expect this patient to have
Muscle fatigue/loss of endurance and muscle weakness.
131
What muscle fibers are affected with age
Type I and II A decrease in muscle mass with age. There is a preferential loss of type II fibers (power/strength versus endurance)
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How and or why do we get stronger with resistance exercises
Neural adaptations at around 2 weeks cause improved synchrony of muscle cells, more ACh production/ release, GTO sensory feedback is down modulated. This reflex normally inhibits muscle contraction to prevent injury/tearing of tissues.
133
Muscle spindle reflex
also deep tendon reflex. Afferent NS initiated. Receptors w/in muscle cells sense quick stretch of muscle cel fibers due to tendon tap and send afferent signal to SC. SC will immediately send efferent signal to muscle fiber to contract and counteract stretch. Descending inhibition moderates response to make it less hyperactive.
134
CNS/UMN injury/disease cause what.
Loss of descending inhibition. Allowing excessive MSR response to occur.
135
No response on one side to the MSR /tendon Tap indicates what
Issue with the PNS
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No response on either side to the MSR/tendon tap
Bilateral lesion or reflex is being covered by tension
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Hyperactive response on both sides to MSR/tendon tap
Damage to CNS b/c loss of descending inhibition
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Golgi Tendon Organ reflex
Afferent NS initiated. GTO stimulation=relaxation. Afferent signal from muscle tendon to SC, interconnections w/in SC from brain CNS system moderate motor output (descending inhibition)
139
UMN injury/diseas most commonly results in
Increased tone/spasticity due to lack of CNS inhibition of muscle reflexes.
140
Muscle spasticity is most likely to be caused by which of the following mechanisms
Loss of CNS inhibition of muscle reflexes
141
Smooth muscle contraction pattern
Phasic- undergo periodic contraction and relaxation cycles(GI)
Tonic- maintain some level of tone (bladder sphincter)
142
Smooth muscle cell communication
Unitary-work together in a coordinated fashion. Connect via gap junctions which allow rapid spread of AP’s among neighboring fibers. Found in walls of vasculature and hallow organs.
Multi unit- Act independently and only when they receive neuronal input. Found in walls of larger arteries, bronchioles, erector pilli and iris of eye.
143
Can smooth muscle regenerate
Yes, more than skeletal and cardiac. Capable of mitosis and regeneration.
144
Why does smooth muscle relax and contract more slowly than cardiac or skeletal
To save energy, maintain absorption.
145
Give an example of smooth muscle that can withstand significant stretching and still function
Bladder
146
Where does calcium come from in a smooth muscle contraction and what protein does It lack that skeletal muscle has
Some form SR and ECF and smooth muscle does not have troponin
147
In smooth muscle how are contractions initiated
Mechanically by stretching, electrically by the ANS stimulation, chemically
148
Why does it take longer for calcium to reach filaments in smooth muscle
There are no t tubules in smooth muscle. Results in lower contraction response than skeletal ms
149
Caveolae
Flask shaped invaginations of the plasma membrane in smooth muscle. Similar function to t tubules as in it deliver Ca2+ to cytoplasm which stimulates SR Ca release and or contraction
150
Protein in smooth muscle that is not found in cardiac or skeletal
Calmodulin. Myosin binding sites blocked by caldesmon. When calcium calmodulin complex binds or caldesmon the myosin binding sites are exposed and myosin actin cross bridges can form.
151
Differences in smooth muscle contractions to skeletal.
Calcium ions from ECF, Ca binds to calmodulin which then binds myosin light chain kinase, the enzyme complex breaks ATP to ADP, when ca pumped out of cell or back into SR inorganic phosphate gets removed from myosin by another enzyme
152
How is cardiac muscle similar to smooth
Single nucleus, contains gap junctions, under ANS and hormonal control
153
What is unique to cardiac muscle
Shorter muscle fibers than skeletal, branched muscle fibers.
154
How is cardiac muscle similar to skeletal
Striated, sarcomere, sarcolemma has t tubules that spread depolarization. Terminal Cisternae, mechanism of muscle contraction (sliding filament)
155
Differences between cardiac and skeletal muscle
Cardiac muscle fibers have smaller diameter than most skeletal. Cardiac muscle contraction is involuntary, cardiac muscle fibers are formed by individual muscle cells with one or two centrally placed nuclei.
156
Intercalated disc
There region where the ends of the cells in cardiac muscles are connected to another cell. Contains gap junctions, adhering junctions, and desmosomes.
157
Why are the cisternae of skeletal muscle larger than that of cardiac
Cardiac muscle is highly vascularized and has more abundant mitochondria because it need to have a lot of endurance.
158
Ischemia
Coronary artery blockage results in cell death called a myocardial infarction or hear attack
159
Muscle at rest
ATP+creatine——->ADP + phosphocreatine
Via creatine kinase
160
Working muscle
Phosphocreatine+ADP——>creatine+ATP (needed for contraction)—->Myosin ATPase(contraction), ca2+ATPase(relaxation), Na-K ATPase restores ions that cross cell membrane during AP)
161
Simple diffusion
Non specific, non saturable. Lipid soluble/steroid hormone, small non-polar, non polar gases,water, lipid soluble drugs
162
Facilitated diffusion
Specific, saturable, no energy required. Down concentration gradient. Charge molecules, large polar molecules, amino acids, metabolic by products, proteins, non diffusable drugs. Carrier proteins involved.
163
Active transport
Specific, saturable, ATP used, carrier proteins involved. Charge molecules, large polar molecules, amino acids, proteins, lipid insoluble drugs, drugs are are endogenously similar to molecules.
164
Vesicular transport
ATP requires, specific, saturable, receptor proteins involved, large particles in large quantities, drug complexes, common mechanism for targeted drug delivery
165
Peripheral proteins
Loosely adhere to other membranes surface inner or outer membrane through hydrogen bonds. Allows disconnection without affecting the structure of the membrane. Receptor, provides structural support, facilitates movement.
166
Integral proteins
Channel- allows small ions to passively move through cell membrane
Carrier- ions specific bonding sites that transport ions passively or actively
