Term
| 3 Functions of skeletal muscle |
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Definition
1) Force production for locomotion and breathing
2) Force production for postural support
3) Heat production during cold stress |
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Term
| List the 5 coverings of the muscle which are made up of connective tissue: |
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Definition
1)Fascia
2)Perimysium
3)Epimysium
4)Endomysium
5)Sarcolemma |
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Term
| List in order each subunit of a muscle from smallest to largest: |
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Definition
| Acting & Myosin Myofilaments -> sarcomere -> Myofibril -> muscle fibers -> Fasicle -> Muscle |
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Term
| List 8 of the microstructures of skeletal muscle: |
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Definition
1) Sarcolemma - muscle cell membrane
2) Myofibrils - threadlike strands within muscle fibers
3) Myofilaments which are composed of Actin and Myosin
4) The sarcomere which is made up of many myofilaments (Z-line, M-line, H-zone, A-band & I-band)
5)Sarcoplasmic reticulum - storage sites for calcium
6) Transverse tubules
7) Terminal cisternae - where Ca2+ is released from
8) Mitochondria |
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Term
| What is a neuromuscular junction and list 2 very important parts of it: |
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Definition
A neuromuscular junction is where motor neuron meets muscle fiber
1) Motor end plate - pocket formed around motor neuron by the sarcolemma
2) Neuromuscular cleft - short gap where ACH travels across. In between the axon and the sarcolemma of a muscle. |
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Term
| What is an end-plate potential (EEP) and what causes it? |
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Definition
| An end plate potential is the depolarization of a muscle fiber which is the signal to begin muscular contraction. It is caused by the release of acetylcholine |
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Term
| What happens with the sliding filament model? |
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Definition
| Muscle shortening occurs due to movement of the actin filament over myosin filaments. |
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Term
| What role do Actin myofilaments and Myosin have to do with the sliding filament model? |
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Definition
| Actin myofilaments slide over myosin to shorten sarcomeres. Actin and myson do not change length. Shortening sarcomeres are responsible for skeletal muscle contraction. |
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Term
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Definition
| When the myosin heads latch on to myosin binding sites on actin in the thin filaments, and the sliding begins. |
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Term
| What diffuses across the synaptic cleft and attaches to receptors on the sarcolemma, opening ion channels and initiating depolarization of the sarcolemma? |
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Definition
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Term
| List the 6 steps in excitation-contraction coupling (Na+ and Ca2+): |
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Definition
1. Net entry of Na+ initiates an aciton potential which is propagated along the sarcolemma and down the T tubules
2. Action potential in T tubule activates voltage-sensitive receptors, which in turn trigger Ca2+ release from terminal cisternae of SR into cytosol
3. Calcium ions bind to troponin
4. Contraction!
5. Removal of Ca2+ by active transport into the SR after the action potential ends.
6. Tropomyosin blockaged restored, blocking myosin biding sites on actin. |
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Term
| What distance of the sarcomere shortens during contraction? |
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Definition
| Distance reduction between the Z-lines. |
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Term
| What is the formation of cross-bridges between acting and myosin filaments also known as? |
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Definition
| A Power Stroke - 1 power stroke only shortens the muscle by 1% |
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Term
| What is the thin filament? What is the thick filament? |
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Definition
Thin filament = Actin
Thick filament = Myosin |
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Term
| What is the energy for muscle contraction? What sources are there? |
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Definition
ATP is required for muscle contraction - Myosin ATPase breaks down ATP as the muscle fiber contracts
Sources of ATP include
1) Phosphocreatine (PC)
2) Glycolysis
3) Oxidative phosphorylation |
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Term
| In regards to high or low for each of the different muscle types, list the oxidative capacity, the amount of ATPase, maximal force production, speed of contraction, and muscle fiber efficiency for Type 1 muscle fibers: |
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Definition
1) Oxidative capacity (# of mitochondria) - High
2) Amount of ATPase - Low
3) Force production - moderate
4) speed of contraction - low
5) Efficiency - High |
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Term
| In regards to high or low for each of the different muscle types, list the oxidative capacity, the amount of ATPase, maximal force production, speed of contraction, and muscle fiber efficiency for Type IIa muscle fibers: |
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Definition
1) Oxidative capacity (# of mitochondria) - High/moderate
2) Amount of ATPase - high
3) Force production - high
4) speed of contraction - intermediate
5) Efficiency - moderate |
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Term
| In regards to high or low for each of the different muscle types, list the oxidative capacity, the amount of ATPase, maximal force production, speed of contraction, and muscle fiber efficiency for Type IIx muscle fibers: |
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Definition
1) Oxidative capacity (# of mitochondria) - low
2) Amount of ATPase - highest
3) Force production - high
4) speed of contraction - highest
5) Efficiency - low |
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Term
| Generally list the individual fiber types and their characteristics: |
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Definition
1. Type I fibers - slow-twitch fibers - Slow oxidative fibers
2. Type IIa fibers - intermediate fibers - fast-oxidative glycolytic fibers
3. Type IIx fibers - Fast-twitch fibers - fast-glycolytic fibers. |
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Term
| With regards to fiber types and performance what are power athletes (sprinters) more like to possess? |
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Definition
| Possess high percentage of fast fibers (about 75%) |
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Term
| With regards to fiber types and performance what are endurance athletes (distance runners) more like to possess? |
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Definition
| Possess high percentage of slow fibers (about 75%) |
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Term
| With regards to fiber types and performance what are weight lifters and non-athletes more like to possess? |
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Definition
| about 50% slow and 50% fast fibers. |
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Term
| With regards to alteration of fiber type by training, what does endurance and resistance training do to you muscle types? |
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Definition
You cannot change fast fibers to slow fibers
You can result in shift from Type IIx to type IIa fibers - toward more oxidative properties. |
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Term
| Which fiber type shows the most response to training? |
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Definition
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Term
| What are the two types of muscle contractions? |
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Definition
1. Isometric - no change in length but tension increases. Postural muscles of the body
2. Isotonic - change in length but tension is constant. |
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Term
| List the two types of Isotonic contractions: |
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Definition
1. Concentric - muscle shortens (going against gravity)(flexing up)
2. Eccentric - muscle lengthens (makes you sore) |
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Term
| What is a muscle twitch? List the three stages of a muscle twitch: |
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Definition
Muscle twitch is a contraction as the result of a single stimulus
1) Latent period - lasting only about 5 ms
2) Contraction - Tension is developed 40ms
3) Relaxation - 50 ms |
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Term
| With regards to force regulation in muscle, what factors increases the force of contraction? |
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Definition
1) more motor units = greater force
2) Fast motor units = greater force
3) Increasing stimulus strength recruits more & faster/stronger motor units |
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Term
| What is the optimal length of a muscle for optimal contraction? |
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Definition
2.25 micrometers
Maximal cross-bridge interaction = maximal tension development. |
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Term
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Definition
| A smooth, sustained muscle contraction resulting from high - frequency stimulation |
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Term
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Definition
| An increase in the frequency of stimulation in a muscle which brings it closer to tetanus. |
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Term
| What is the force-velocity relationship for muscle fiber types? |
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Definition
At any absolute force, the speed of movement is greater in muscles with a higher percent of fast-twitch fibers
-The maximum velocity of shortening is greatest at the lowest force. This is true for both slow and fast-twitch fibers. |
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Term
| What is the force-power relationship? |
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Definition
At any given velocity of movement, the power generated is greater in a muscle with a higher percent of fast-twitch fibers
-The peak power increases with velocity up to movement speed of 200-300 degrees/sec.
-Force decreases with increasing movement speed beyond this velocity |
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Term
| Where are the muscle spindle receptors found and what are the effects of stimulation on this receptor? |
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Definition
Located in a group of skeletal muscle fibers.
Intrafusal fiber contains actin and myosin, and therefore has the ability to shorten. Gamma motor neuron stimulates muscle spindle to shorten. Changes in muscle length. Causes the muscle to contract and resist being stretched. |
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Term
| What does the golgi tendon organ do? What does stimulation of this result in? |
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Definition
Monitors tension developed in muscle (sensed in tendon)
Prevents damage during excessive force generation
-Stimulation results in reflex relaxation of muscle (IPSP) |
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Term
| What is the stretch reflex? |
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Definition
| Stretch on a muscle causes reflex contraction - knee-jerk reflex. |
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Term
| 3 purposes of the cardiovascular system: |
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Definition
1. Transports O2 to tissues and removes waste
2. Transport of nutrients to tissues
3. Regulation of body temperature |
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Term
| Circulatory system consists of what 4 major things? |
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Definition
1. Heart - pumps blood
2. Arteries and arterioles - carry blood away from the heart
3. Capillaries - Exchange of nutrients with tissues
4. Veins and venules - Carry blood toward the heart |
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Term
| List the order of blood flow through the heart: |
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Definition
| Right atrium, tricuspid valve, right ventricle, pulmonary artery, lungs, pulmonary veins, left atrium, bicuspid valve, left ventricle, aorta, rest of the body |
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Term
| List characteristics of the pulmonary circuit: |
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Definition
1. Right side of the heart
2. pumps deoxygenated blood to the lungs via pulmonary arteries
3. Returns oxygenated blood to the left heart via pulmonary veins |
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Term
| List characteristics of the systemic circuit: |
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Definition
1. Left side of the heart
2. Pumps oxygenated blood to the whole body via arteries
3. Returns deoxygenated blood to the right heart via veins. |
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Term
| List the three layers of the heart from outside to inside. |
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Definition
1) Fibrous pericardium
2) Serous pericardium
3) Epicardium - serous membrane, serves as lubricative outer covering
4) Myocardium - cardiac muscle tissue, provides muscular contractions that eject blood from heart chambers.
5) Endocardium - Endothelial tissue, serves as protective inner lining of the chambers and valves. |
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Term
| What is systole and what is diastole? What are their time divisions at rest? at exercise? |
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Definition
Systole - contraction phase. At rest - 0.3 seconds. At exercise - 0.2 seconds
Diastole - relaxation phase. At rest - 0.5 seconds. At exercise - 0.13 seconds. |
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Term
| What is the pressure needed for systole? What is the pressure during diastole? |
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Definition
Systole pressure = 120 mmHg
Diasatole pressure = 0 mmHg |
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Term
| What is pulse pressure? What is the equation for it? |
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Definition
The difference between systolic and diastolic
Pulse pressure = Systolic - Diastolic |
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Term
| What is mean arterial pressure (MAP)? What is the equation for it? |
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Definition
Average pressure in the arteries
MAP = Diastolic + 1/3(pulse pressure) |
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Term
| List 5 factors which influence arterial blood pressure: |
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Definition
1) Blood volume increases
2) Heart rate increases
3) Stroke volume increases
4) Blood viscosity increases
5) Peripheral resistance increases |
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Term
| Contraction of the heart depends on electrical stimulation of which layer of the heart? List the path of electrical activity through the heart. |
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Definition
The myocardium
1)SA node
2)AV node
3)Bundle of his
4)Right and left bundle branches
5)purkinje fibers |
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Term
| What does the P-wave represent? QRS complex? T-wave? |
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Definition
P-wave = atrial depolarization
QRS complex = Ventricular depolarization
T-wave = Ventricular repolarization |
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Term
| What is cardiac output? What is the equation for it? |
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Definition
The volume of blood pumped by the heart (per minute)
Q = Heart Rate x Stroke Volume
Heart rate = number of beats per minutes
Stroke volume = amount of blood ejected in each beat. |
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Term
| During exercise, control of Q means regulation of what? |
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Definition
| Heart rate and stroke volume! |
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Term
| With regards to regulation of heart rate, what happens with the parasympathetic and sympathetic nervous systems? |
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Definition
The parasympathetic is in charge of decreasing the heart rate. Via the vagus nerve. It slows the heart rate by inhibiting the SA node(ACH)
The sympathetic nervous system is in charge of increasing the heart rate. Via the cardiac accelerator nerves. It increases the heart rate by stimulating the SA node (NE) |
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Term
| What are the three things involved with the regulation of stroke volume? |
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Definition
1) End-diastolic volume (EDV) - Volume of blood in the ventricles at the end of diastole ("preload")
2) Average aortic blood pressure - pressure the heart must pump against to eject blood ("afterload")
3) Strength of the ventricular contraction - contractility |
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Term
| During end diastolic volume, what is the frank-Starling mechanism? |
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Definition
| A greater preload results in a stretch of ventricles and in a more forceful contraction |
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Term
| During end diastolic volume, what 3 things affects the frank-starling mechanism? |
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Definition
1) Venoconstriciton
2) Skeletal muscle pump - aids in venous return to heart
3) Respiratory pump - negative pressure in the chest promotes venous return. |
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Term
| What is the skeletal muscle pump? |
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Definition
| Rhythmic skeletal muscle contractions which force blood in the extremities toward the heart. One way valves in veins prevent back flow of blood |
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Term
| Explain average aortic pressure and how it relates to stroke volume: |
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Definition
Aortic pressure is inversely related to stroke volume
High afterload results in a decreased stroke volume
-Required greater force generation by the myocardium to eject blood into the aorta
- Hypertension
Reducing aortic pressure results in higher stroke volume |
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Term
1) Aortic pressure is related to stroke volume how?
2) High after load results in a (increased/decreased) stroke volume
3) Reducing aortic pressure results in (higher/lower) stroke volume |
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Definition
1)Inversely
2)Decreased
3)Higher |
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Term
With regards to ventricular contractility, increased contractility results in higher/lower stroke volume?
This is due to what? |
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Definition
Higher
Due to circulating epinephrine and norepinephrine
-Direct sympathetic stimulation of heart
-Beta blockers |
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Term
Factors that affect cardiac rate include?
Factors that affect stroke volume include? |
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Definition
Cardiac rate = decrease in parasympathetic nerves, increase in sympathetic nerves
Stroke volume - Decrease in arterial pressure, increase in contraction strength, increase in EDV |
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Term
| Factors that regulate cardiac output? |
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Definition
1) EDV - venous return
-Venoconstriction
-Muscle pump
-Respiratory pump
2) Average aortic pressure
-Sympathetic afterload = PS stroke volume
-PS afterload = sympathetic stroke volume
3)Ventricular contractility
- Epinephrine/norepinephrine
- Neural stimulation
- Pharmaceuticals (beta blockers = parasympathetic) |
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Term
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Definition
| The study of the physical principles of blood flow |
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Term
What is the plasma part of the blood?
What is the cells part of the blood? |
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Definition
Plasma is the liquid portion of blood and consists of ions, proteins, and hormones
Cells consists of red blood cells which consists of hemoglobin which carries oxygen. Cells also consists of white blood cells which help fight infection and platelets which aid in blood clotting. |
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Term
| What does dehydration during exercise do to your blood? |
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Definition
| alters the blood viscosity. Makes it thicker. |
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Term
| In regards to blood flow, how does pressure affect blood flow? |
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Definition
Blood flows from high to low pressures
-Proportional to the difference between MAP and right atrial pressure (change in P) "driving pressure" |
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Term
| With regards to blood flow, what 3 things does resistance depend upon? |
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Definition
1) The length of the vessel
2) Viscosity of the blood
3) Radius of the vessel
-A small change in vessel diameter can have a dramatic impact on resistance! |
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Term
| Which of the three factors involved in resistance has the most impact on resistance? What is the equation for resistance? |
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Definition
Radius of the vessel
Resistance = (length x viscosity) / radius |
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Term
How does blood flow factor in to hemodynamics?
Equation for blood flow? |
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Definition
Blood flow is directly proportional to the pressure difference between the two ends of the system. Inversely proportional to resistance
Flow = (change in pressure) / Resistance |
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Term
| Why is there vascular resistance? and where does the largest drop in vascular resistance occur? |
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Definition
MAP decreases throughout the systemic circulation
The largest drop occurs across the arterioles. The arterioles are celled "resistance vessels"
-"bottle neck" if resistance to blood flow becomes a problem |
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Term
| During exercise, oxygen demand by the muscles is many times greater than at rest. The increased O2 delivery is accomplished by what two things? |
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Definition
1) Increased cardiac output
2) Redistribution of blood flow to skeletal muscle |
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Term
What changes occur to increase Q during exercise?
Max HR equation:
Fick Equation: |
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Definition
1) increased heart rate - linear increase to max
2) increased stroke volume - plateau at about 40% VO2 max
Max HR = 220 - age
Fick Equation = VO2 = Q x (a-VO2 difference) |
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Term
| What two ways can the blood flow be redistributed? |
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Definition
1) Muscle blood flow increases to working skeletal muscle
2) Splanchnic blood flow decreases to less active organs like the liver, kidneys, and GI tract. |
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Term
| Heart rate and blood pressure depend on what 3 external things? |
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Definition
1) Type, intensity, and duration of exercise
2) Environmental condition
3) Emotional influence |
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Term
| What is the double product, and what is the equation for it? |
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Definition
A measure of the work load of the heart, equal to systolic blood pressure multiplied by heart rate.
Double product increases linearly with exercise intensity which indicates the work of the heart
Double product = heart rate x systolic blood pressure |
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Term
| How does the transition from exercise to recovery differ between untrained and trained individuals? |
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Definition
Trained - steady state achieved quicker and recovery is faster
Untrained - steady state takes longer to achieve and recovery takes longer. |
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Term
| At a given oxygen uptake, which work (arm/leg) results in higher heart rate, blood pressure, and VO2 max? |
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Definition
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Term
What effect is seen with prolonged exercise?
What is cardiovascular drift? |
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Definition
Cardiac output is maintained. Gradual decrease in stroke volume and a gradual increase in heart rate.
Cardiovascular drift - A drifting upwards of heart rate when exercise is performed at a constant work rate over a prolonged period or in a hot environment. The cardiovascular drift is associated with sweating and a redistribution of blood so that peripheral circulation is increased. Body fluids are lost, reducing the volume of blood returning to the heart causing a decrease in stroke volume (see Starling's law). The heart rate increases in an attempt to compensate for the lower stroke volume and maintain a constant cardiac output. Due to dehydration, increased skin blood flow (rising body temp.), alterations in blood catecholamine levels |
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Term
Mechanoreceptors sense what?
Chemoreceptors sense what?
Baroreceptors sense what? |
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Definition
Mechanoreceptors sense mechanical pressure
Chemoreceptors sense a change in chemical signals or activity
Baroreceptors sense pressure |
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Term
| Hemodynamics is based on what three interrelationships? |
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Definition
1) Pressure
2) Resistance
3) Flow |
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