Exam 3 Flashcards
1
Q
Skeletal Muscle Contraction Activation
A
1) The sarcoplasmic reticulum releases Ca2+
2) Ca2+ binds to troponin (which is bound to tropomyosin
3) Troponin changes conformation
4) Tropomyosin is lifted off the myosin binding sites location on actin
5) The Actin-Myosin interaction may occur
2
Q
Troponin
A
Globular regulatory protein for skeletal and cardiac muscle located on actin which holds down tropomyosin so the myosin sites are blocked. What Calcium ions actually bind to.
3
Q
Tropomyosin
A
Rod shaped regulatory protein for skeletal and cardiac muscle contraction. Wraps around actin and blocks the myosin binding sites on actin.
4
Q
Actin
A
Thin filament made of a globular protein chain with cross bridge binding area
5
Q
Myosin
A
Tick filament made of thick chains with a cross bridge head which has a binding site for actin and ATP/ase
6
Q
Myoneural Junction
A
Same as a neuromuscular junction. Has an increased surface area with invaginations where acetylcholine receptors are located
7
Q
Activated Crossbridge Intermediate
A
MyosinADPPi
8
Q
Sliding Filament Mechanism
A
ATP binds to myosin making activated crossbridge intermediate. Myosin crossbridge binds to actin. Immediately the crossbridge changes conformation pulling actin over and releasing ADP*Pi to make the actin-myosin complex
9
Q
Skeletal Muscle
A
Large/long cells that are multinucleated and striated with mitochondria on the outside… sarcoplasmic reticulum.
10
Q
Sarcomeres
A
Repeating patters of actin and myosin
11
Q
Structure of a Muscle
A
Tendons attach at the origin and insertion points, connective tissue surrounds the muscle fiber (cell), which is composed of many myofibrils that which have many sarcomeres
12
Q
Actin/Myosin Arrangement
A
For each thick filament there are two thin filaments. But a single myosin is surrounded by six actin and then each actin is surrounded by three myosin making a kind of honeycomb pattern.
13
Q
Sarcoplasmic reticulum
A
Homologous to the ER in a cell. Forms a series of sleevelike segments around each myofibril. At each end there are terminal cisternase.
14
Q
Terminal Cisternase
A
Ends of sarcoplasmic reticulum where the Ca2+ is stored and then released from into the cytosol following membrane excitation. Closely associated with the T-Tubules.
15
Q
Motor Neurons
A
(Somatic Efferent Neurons) The neurons whose axons innervate skeletal muscle fibers, and their cell bodies are located in the brain-stem and the spinal cord.
16
Q
Motor Unit
A
A motor neuron and the muscle fibers it innervates. A single neuron innervates many muscle fibers but each muscle fiber is controlled by a branch from only one motor neuron.
17
Q
Motor End Plate
A
The region of the muscle fiber plasma membrane that lies directly under the terminal portion of the axon
18
Q
Neuromuscular Junction
A
The junction of an axon terminal with the motor end plate
19
Q
Transverse Tubules
A
(T Tubules) Lies directly between terminal cisternae of adjacent segements of the SR, both of which surround the myofibrils. T-Tubules continuous with the PM and the AP propagating along the surface membrane also travels throughout the interior of the muscle fiber by why the T-Tubule. Lumen is continuous w/ ECF surrounding muscle fiber.
20
Q
Skeletal Muscle ATP Requirements
A
- Crossbridge movement
- Breaking the Actin-Myosin Link
- For Ca ATPase
21
Q
Motor End Plate Events
A
1) The action potential causes Ca Channels to open at the axon terminal
2) Increase in intracelluar Ca causes ACH vesicles to migrate and fuse with cell membrane, expelling content
3) Ach binds to the receptor(nicotinic), diffuse away, active reuptake, enzymatic degradation
4) Ach-Receptor opens channels post membrane depolarization
5) Muscle fiber action potential after threshold
22
Q
Curare
A
Antagonist binds to receptors
23
Q
Organophosphates
A
Inhibit acetylcholinesterase
24
Q
Botulism Toxins
A
Blocks Ach release
25
Mynsthenia Gravis
Decrease Ach release
26
Choline Acetyl Transferase
Forms Ach
27
Acetylcholine Esterase
Breaks down Ach
28
Excitation Contraction Coupling
- Resting state
- Membrane depolarization and repolarization
- --Na channels...open,close
- --K channels....open,close
- Depolarization sweeps through T-Tubule System
- T-Tubule system releases Ca stimulating sarcoplamic reticulum
- To release Ca by channels
- After Ca release is finished Ca ATPase pups Ca back into SR
- As Ca is removed troponin-topomyosin goes back to resting state
29
Activating Actin
1) Tropomyosin covers myosin binding sites on actin with troponin keeping it in place
2) Ca2+ levels are increased
3) Ca2+ binds to troponin
4) Binding changes shape of troponin
5) Troponin lifts tropomyosin off the myosin binding site on actin
6) Normal Actin-Myosin interactions can then occur
30
Sliding Filament Mechanism Major Steps
Initiation and Perpetuation. Note initiation happens once and repetition many times.
31
Dihydropyridine receptor
(DHP Receptor) T-Tubule membrane protein that is a modified voltage-sensitive channel whose main job is not to conduct Ca but rather to act as a voltage sensor.
32
Initiation of The Sliding Filament Mechanism
1) Myosin binds to ATP
2) Binding activates actin-binding site on myosin crossbridge by using some of the ATP energy
3) The Myosin*ADP*Pi complex binds actin using the myosin crossbridge
4) This binds actin by using energy from the ADP*Pi and causing crossbridge to move and ADP*Pi is split from myosin
5) Leaves Actin-Myosin Complex
33
Perpetuation of The Sliding Filament Mechanism
1) Have Actin-Myosin Complex
2) ATP binds myosin and myosin 'releases' actin
3) Myosin activated by myosin*ADP*Pi
4) The myosin*ADP*Pi binds to actin
5) Crossbridge activity so ADP*Pi is lost
6) Back to 1
34
Rigor Mortis
Cross bridges remain bound
35
Changes During Sliding Filament Mechanism
Shortening of the sarcomeres occurs with an additive shortening of the z-lines. The thick and thin filaments do not change size.
36
Contraction
Does not necessarily mean shortening but simply refers to activation of the force-generating sites within muscle fibers known as cross-bridges.
37
Skeletal Muscle ATP Sources
Oxidative Phosphorylation , Glycolysis, and Creatine Phosphate
38
Oxidative Phosphorylation
Uses fat? ADP+Pi---ATP in mitocondria and makes water and CO2
39
Glycolysis
(glucose/glycogen in cytoplasm can make lactic acid if fermented) ADP+Pi---ATP
40
Creatine Phosphate
More of a stop-gate measure to keep it going. Uses the enzyme Creatine kinase to take CP + ADP ----ATP + C
41
Factors for Muscle Tension
- Number of muscle fibers contraction (recruitment increased by neural input)
- Amount of tension developed by each fiber
- Optimal stretch/length (arrangement of actin and myosin)
42
Single Twitch
Normal contraction and relaxation
43
Muscle Contraction graph
Latent period after stimulation and then increase of distance shortened until peak around 80ms followed by a 40ms relaxation
44
Summation
Incomplete relaxation so the muscle contracts and this additional contraction adds onto the previous contraction.
45
Fusion
Incomplete contraction and relaxation. Known as unfused tenanus
46
Tenanus
The muscle is completely twitched maintained maximal response to excessive stimulation for complete contraction
47
Fatigue
Muscle relaxation due to loss of energy/fuel, lack of oxygen, and or change in pH
48
Disuse Atrophy
Decrease in muscle size due to a decrease in myofibrils no cell number because of disuse. SKELETAL MUSCLE IS MADE TO BE USED
49
Degenerative Atrophy
Nerve linkage is lost, trophic components are not being received, shrinks in size.
50
Muscle Arrangement
Antagonistically - Note the muscle arrangement for moving the leg; the more joints involved the faster the movement.
51
Hypertrophy
Increase in muscle size due to an increase in myofibrils, not cell number. Increased protein content and or increased circulation.
52
Increased Contractile Activity
Altered ATP forming capacity and or myofibril number in the cell increases.
53
Myoglobin
Oxygen binding protein of th emuscle fiber M-O2; increases O2 diffusion.
54
Oxidative Fibers
Skeletal muscle fibers with numerous mitochondria and a high capacity for oxidative phosphorylation. Also have high amounts of myoglobin and referred to as "red" fibers.
55
Glycolytic Fibers
Skeletal muscle with few mitochondira but have high concentration of glycolytic enzymes and a large store of glycogen. "white" fibers. Larger diameters and more maximum tension.
56
Slow-Oxidative Fibers
Type 1 skeletal fibers that combine low myosin-ATPase activity with high oxidative capacity. High in myoglobin = dark red. Tension (mg) constant over time.
57
Fast-Oxidative-Glycolytic Finbers
Type 2a skeletal fibers the combine high mysoin-ATPase activity with high oxidative capacity and intermediate glycolytic capacity. High in myoglobin + glycogen = white. Tension (mg) slowly drops off over time.
58
Fast-Glycolytic Fiber
Type 2b skeletal fibers that combine high myosin-ATPase activity with high glycolytic capacity. Low in myoglobin = white. Tension (mg) quickly drops off over time.
59
Whole Muscle Contraction
Each muscle is made of all three fiber types in different ratios. Recruit slow-ox, fast-ox-gly, and fast-gly.
60
Low-Intensity Exercise
Aerobic exercise with low intensity and long duration. Increases mitochondria number in fibers.
61
High-Intensity Exercise
Short duration and high intensity affecting fast-twitch fibers used for strong contractions. Fibers increase in diameter.
62
Smooth Muscle General
Small spindle cell, made of actin and myosin, uses Ca ion/Calmodulin control, under autonomic nervous system, and has gap junctions.
63
Smooth Muscle Structure
Thick and thin filaments in smooth muscle are arranged in diagonal chains that are anchored to the plasma membrane or dense bodies
64
Dense Bodies
Cytoplasmic structure that anchor think filaments in smooth muscle. No set arrangement accounts for lack of striation.
65
Smooth Muscle Contraction Shape
When relaxed, the cell is long and thin. When contracted, the cell becomes shorter and wider.
66
Smooth Muscle Contraction
Excitation Contraction Coupling
1) Muscle cell action potential
2) Voltage-sensitive Ca2+ channels open
3) Increase in intracellular Ca2+
4) Activates Calmodulin
5) Activates Protein Kinase (myosin (light-chain) kinase)
6) The myosin kinase phosphorylates the myosin crossbridge into myosin-PO4
7) Actin binds and crosbridge moves
8) Ca2+ stays myosin remains.
67
Smooth Muscle Relaxation
Myosin light-chain phosphatase must dephosphorylate myosin. Ca2+ channels close and CaATPase removes intracellular Ca.
68
Smooth Muscle Sustained Tension
Continues as long as it is phosphorylated. No fatigue.
69
Smooth Muscle Compaired to Skeletal
Longer contractions, lacks striations/no sarcomeres, ANS, similar strength, greater effective length/stretch, both use sliding filaments, slow contractions from love myosine ATPase activity.
70
Smooth Muscle Factors
Spontaneous electrical activity, neurotransmitters, hormones, local changes, stretch
71
Pacemaker Cells
Cells that spontaneously depolarize to threshold potential voltage and act to coordinate other cells. 1%
72
Neurotransmitters Affect Smooth Muscle
Sympathetic uses norepinephrine to excite or inhibit. Parasympathetic uses acetylcholine
73
Muscle Tone
Prolonged response of smooth muscle fibers where tension is related to intracellular calcium.
74
Smooth Muscle Single Unit
Each muscle fiber is linked by gap junctions for electrical communication. Located in intestines, uterus, and small diameter vessels.
75
Smooth Muscle Multiunit
Few gap junctions so communication occurs with nerves and rich innervation. Located in trachea, bronchioloes, large arteries, and skin hairs.
76
Asthma
Constriction of bronchi smooth muscle
77
Cardiac Musle Cells
Striated, contraction Ca activated by Ca stores in sarcoplamic reticulum/ECF, uses actin/myosin with troponin/tropomyosin, regulated by nerves, hormones, stretch, pacemaker cells, slow contraction rate, has gap junctions, and rich in mitochondria.
78
Measurement of Blood by Centrifugation
Plasma 55%, Leukocytes and platelets, Erythrocytes 45%
79
Hematocrit
Percentage of blood that is erythrocytes/red blood cells. Higher levels increase viscosity.
80
Blood Flow Rate
At rest 5800ml/min and 17,500ml/min during strenuous exercise. Blood flow changes based on need.
81
Ventricles
Move blood out of the heat when exceeds systemic pressure
82
Blood Flow Path in Heart
Superior/inferior vena cave, right atrium, tricuspid valve, right ventricle, pulmonary semilunar valve, pulmonary artery, lungs, pulmonary veins, left atrium, bicuspid valve, left ventricle, aortic semilunar valve, aorta/arteries, systemic circulation.
83
Systole
Ventricular Contraction
84
Diastole
Ventricular Relaxation
85
Systolic
Sound of ventricular contraction
86
Diastolic
Sound of ventricular relaxaion
87
"lub"
AV (bi/tricuspid) valves closing
88
"dub"
semilunar valves closing
89
Cardiac Output
Heart Rate(bmp) X Stroke Volume(liters/beat) = CO(liter/min)
90
Sphygmomanometer
Devise used to measure blood pressure and hear rate
91
Korotkoff Sounds
First occurs when cuff pressure is just below systolic pressure. Last when cuff pressure drops below diastolic pressure
92
Electrical Heart Signal Pathway
Sinoatrial node starts action potential and will depolarize for atrial excitation until it reaches the atrioventricula node where signal is delayed and filtered. Passes on AP though Bundle of His, Bundles of His, up though Purkinje fibers. Contracts down up.
93
Myogenic
Contractile event generated by the muscle itself like the heart.
94
Tachycardia
Fast heart rate
95
Brachycardia
Slow heart rate
96
Grammar of Heart Stuff
Imply ventricular unless it says atrial. ic=sound e=contraction
97
EKG P Wave
Atrial depolarization and atrial contraction
98
EKG QRS Wave
Ventricular depolarization and ventricular contraction
99
EKG T Wave
Ventricular repolarization and ventricular relaxation
100
Ectopic Focus
an area of the atria or ventricles that initiates another contraction, a contraction that is not in the normal cycle.
101
Heart Contraction Movement
Fibers arranged longitudinally then move to a 90* angle. Discontinuous pump that must reload/long refractory period.
102
Nervous System Heart Controls
Parasympathetic brings heart rate down and will override the sympathetic that brings heart rate up
103
Increase Heart Rate
Increase cardiac sympathetic nerve activity, Increase plasma epinephrine, decrease parasympathetic nerve activity.
104
Increase Stroke Activity
Increase cardiac sympathetic activity, increase end-diastolic ventricular volume, increase plasma epinephrine.
105
Stroke Volume
Amount of blood moved out of the heart with a contraction
106
Starling's Law
There is a direct relationship between the end diastolic volume of the heart and the force of contraction. Related to venous return.
107
Blood Movement Equation
Flow=Change in pressure/resistance (a pump is p and a closed system is delta p)
108
Flow
Flow is affected by pressure and resistance
109
Systemic and Pulmonary Pressure
Systemic circulation has a higher pressure 80-120 while pulmonary circulation 10-30.
110
Greatest area of resistance
arterioles
111
Laminar Flow
When there is a normal open valve and it is quiet. Normal closed should also be quiet because no flow.
112
Stenotic Valve
Narrowed valve with turbulent flow causing a murmur
113
Insufficient valve
leaky and doesn't close all the way resulting in turbulent back flow and a murmur
114
Changing Pressure
All comes from the heart so depends on stroke volume and heart rate
115
Changing Resistance
Depends on viscosity, length, and radius.
116
Pressure reservoir
arteries
117
variable-resistance outflow tubes
arterioles
118
Blood Components
Formed elements and plasma
119
Formed Elements
RBC 5*10^9, WBC 7*10^9, platelets 250*10^6
120
Plama
Non cellular, fluid, salt, proteins
121
Hematocrite Percentages
43-49% in males, 36-45% in females
122
Resistance
Affected by radius, length, and viscosity
123
Length
Inversely related so doubling the length halves the resistance
124
Radius
Inversely related by the power of 4. Twice the radius is 16x the resistance.
125
Fat Deposit Effects
Decrease elasticity, increase resistance, increase blood pressure, increase stenosis
126
Pressure as Blood Flows
Heart, Artery 100-200, arterioles 60-70, capillary 30-40, venule 10-20, vein -5-10
127
Arteries - Elastic
Has smooth muscle to expand and come back down. Guarantees consistent flow of blood.
128
Arteries - Radius
Large for low resistance endothelium. Regulatory component.
129
Arteries - Pule Pressure
Determined by stroke volume, volume velocity/flow, and arterial distensibility which decreases with age.
130
Endothelium
The inner most single cell layer thick lining of the vessel
131
Mean Arterial Pressure
Cardiac Output * Total periphrial resistance OR diastolic+1/3(pulse pressure)
132
Total Peripheral Resistance
Viscosity and arteriolar radius (local effects, sympathertic nerves, plasma epinephrine and angiotensin II
133
Local Effects on Total Peripheral Resistance
Arterioles vasoconstrict or vasodialte depending on the tissue's needs. Decrease in O2 or increase in water increases organ blood flow
134
Capillary
A single cell thick vessel that provides an area for the movement of molecules between the blood and cells like nutrients and waste products. Greatest cross sectional area for lowest velocity but high constant resistance. Diffusion and active transport area. Flow controlled by precapillary sphincter.
135
Capillary Control
Autocontrolled by local pH and precapillary sphicter.
136
Precapillary Sphincter
Controls blood flow into capillaries. Only 3% open at a time or else heat would drain of blood.
137
Capillary Physical Pressure
Affected by capillary blood pressure. Cell pressure = intersitial pressure = 0
138
Capillary Osmotic Pressure
Salt concentration the same between blood and ECT but proteins are large and will not diffuse. Tendency to take in water.
139
Filtration Equation
(Pp-Pi) - (OPp-OPi)
140
Arteriole Filtration End
Normally positive where water is leaving the capillary
141
Venule Filtration End
Physical pressure decreases because resistance usually does yielding negative filtration and water moving in.
142
Venous Return Factors
Sympathetic nervous system, skeletal muscle activity, inspiratory movements, blood volume
143
The Lymphocytes
Systemic capillaries except the kidneys. Filter 20L/day, Absorb 17L/day, Lymph 3L/day
144
Edema
Increase of fluid in tissue or organ from increased intersitial fluid from obstruction
145
Lymph System
Return fluid, return proteins, filter/immune
146
Venous System
Normally closed system, 60% of volume in venules and veins, pressure 15--0, low resistance from large radius
147
Venous System Driving Forces
Closed system (stuff going down pulls other stuff up), large flexible vessels, one-way valves.
148
Venous Link to BP
Venous pressure, venous return, atrial pressure, end-diastolic ventricular pressure, stroke volume
149
Atrial Pressure
Changes centricular colume. More blood to the atria, the more to the ventricles--venus return
150
Venus Return Factors
Sympathetic nervous system contract smooth muscle vein, skeletal muscle activity contractions compress thin walled vessels, inspiratory movements more negative in the chest increased pressure in abdomen, and blood volume
