Studied by 1 person
What is an individual muscle cell?
Muscle Fiber
What are the clusters of proteins within each muscle cell?
Myofibrils
A membrane has (single/multiple) nuclei
Multiple (multinucleated)
Muscles cells (do/do not) divide in adulthood.
do not
When muscle tissue dies, it (does/does not) grow back
does not
Neuron that innervates a muscle cell.
Motor Neuron
What is the name of the endoplasmic reticulum in muscle cells?
Sarcoplasmic Reticulum
What is stored in the sarcoplasmic reticulum?
Calcium
Where are T-Tubules found?
in the muscle membrane & runs deep into the myofibrils
Where is the motor end plate found?
Muscle Cell Membrane
Explain the process of moving your finger...
Acetylcholine gets released from motor neurons then binds to receptors on the end plate (depolarization).
Channels open: Sodium comes in, Potassium goes out.
End plate potential develops action potentials.
All contractions happen (at once/in a sequence)
in a sequence
Thick and thin filaments come in contact with each other at _______.
crossbridges
What two things do all muscle contractions require?
Calcium & ATP
What keeps myosin from being in contact with actin?
Troponin
What moves tropomyosin around?
-calcium binding site, actin binding site, tropomyosin binding site
Troponin
What covers up the binding site on actin when muscles relax?
-extends along thin filaments, masks myosin binding site in absence of calcium
Tropomyosin
How does a cramp occur?
By involuntary skeletal muscle contraction
Name the regulatory proteins:
Tropomyosin & Troponin
Made up of two strands of actin that form double helix
Thin Filaments
Made up of myosin dimers bound together at tails, binding sites on heads (crossbridges) for actin, ATPase site
Thick Filaments
______ gives permission for contractions to occur.
Calcium
Name the steps of muscle contraction:
Motor Neuron Action Potential
End plate potential (excitation)
Increase in muscle cell calcium levels
Troponin and Tropomyosin conformation change
Crossbridge cycling to sliding filaments (CONTRACTION)
Calcium binds to ______ to move ______ out of the way, which causes a contraction.
Troponin/ Tropomyosin
Another name for calcium channels in the sarcoplasmic reticulum
Ryanodine Receptors
What is the job of DHP receptors?
detect action potentials and when they do, they change shape and pull open calcium channels (Ryanodine receptors) so calcium goes out of SR into the muscle cell.
-voltage sensor
The majority of calcium needed in a muscle cell comes from ______ receptors.
DHP
When ATP binds to myosin, myosin now has a ______ affinity for actin.
Low
When ATP binds to myosin, the muscle contraction (starts/stops) and myosin lets go of actin.
stops
When attached to ADP, myosin has a _____ affinity for actin.
High
When myosin is attached to ADP, actin binds to it, forming a ________ between myosin and actin.
Cross-Bridge
What causes the myosin head to close causing the power stroke?
Release of an inorganic phosphate
You need more ______ to relax muscles.
-this is why dead bodies are stiff
ATP
Name the ways muscle contraction is terminated:
Motor neuron input terminates
End plate potentials terminate
High myoplasmic calcium concentration shuts SR calcium channels
Active calcium uptake through SERCA pumps on SR move calcium from cytoplasm to SR.
Calcium dissociated from troponin
Tropomyosin covers myosin binding sites on actin
The most work that a single action potential can produce.
-The mechanical response or change in force/tension (measured in grams) of an individual muscle fiber, motor unit, or whole muscle to a single action potential
Twitch
Muscle-generated force causes muscle shortening and lifts a load.
-load must be less than or equal to muscle tension. -Ex: grabbing a chair and actually lifting it. (moving the load)
Isotonic Twitch
Muscle-generated force but does not shorten (load/force opposing muscle shortening is greater than muscle tension) the muscle can't shorten.
-Ex: pushing against a wall...it doesnt not move even though you are exerting force on it.
Isometric Twitch
The amount of time it takes for a fiber to respond after you've told it to respond
-time of thinking about it until it actually happens
Latent Period
Contain slow myosin
-hydrolyzes ATP to ADP and P slower, myosin head cocking is slower
Slow Twitch Fibers
Contain fast myosin
-hydrolyzes ATP to ADP and P faster, myosin head cocking is faster
Fast Twitch Fibers
T/F: Skeletal muscles can contain slow twitch fibers, fast twitch fibers, or both.
True
T/F: Conditioning and training muscle can teach the muscle to respond more quickly.
True
Anaerobic generation of ATP
Glycolytic
Aerobic generation of ATP
Oxidative
Fibers that have a high concentration of glycolysis enzymes
Glycolytic
Fibers that have a low concentration of glycolysis enzymes
Oxidative
Fibers that contain a lot of mitochondria
Oxidative
Fibers that contain myoglobin (oxygen storage molecule)
Oxidative
Fibers that are large in diameter
Glycolytic
Fibers that have less blood flow and are lighter in color
Glycolytic
What type of exercise increases oxidative fiber capacity?
-conversion of some glycolytic fibers into oxidative fibers
Low Intensity (yoga, pilates)
What type of exercise increases glycolytic capacity & decreases oxidative capacity?
-conversion of some oxidative fibers into glycolytic fibers -fatigue is caused by lactic acid buildup -depletion of ACh
High Intensity (out of breath)
T/F: smooth muscle has no sarcomeres but crossbridge cycling still occurs.
True
Calcium for smooth muscle comes from (inside/outside) the cell.
Outside
Calcium for skeletal muscle comes from (inside/outside) the cell.
Inside (sarcoplasmic reticulum)
In smooth muscle, actin and myosin connect to connective tissue at ______ ______.
Dense Bodies
Calcium binds to ______ in smooth muscle.
Calmodulin
Calmodulin binds and activates what enzyme in smooth muscle allowing cross bridges to form?
MLCK: Myosin Light Chaine Kinase
What shuts off smooth muscle contraction?
Inactivation of myosin by phosphatases, which remove phosphate group from myosin light chain.
What would be the consequence if phosphatases stopped being produced in a cell?
smooth muscle would stay contracted too long
Name the 3 components of the cardiovascular system
Blood, Blood Vessels, Heart
What are the 2 ways to increase pressure in the heart?
Add more blood
Contract the chamber of the heart
What are the 2 main components of blood?
Blood cells & plasma
What are the components of blood cells?
Erythrocytes Leukocytes Platelets
Red blood cells -carry oxygen bound to hemoglobin (contains iron)
Erythrocytes
White blood cells -Mediate immune responses
Leukocytes
Cell "fragments" -aid in blood clotting
Platelets
Liquid portion of blood-yellow part -mostly water and proteins, antibodies, and ions.
Plasma
Blood vessels that transport blood away from the heart (3)
Arteries, arterioles, capillaries
Blood vessels that transport blood to the heart (2)
Veins & venules
Pulmonary refers to:
Lungs
Systematic refers to:
everything except the lungs
Largest artery and blood vessel in the body & carries blood from the left ventricle to everywhere in the body. -high pressure
Aorta
T/F: blood flows from the pulmonary circuit to the systematic circuit in the body.
True
In systematic capillary beds, ______ leaves the blood and ______ enters.
O2 enters CO2 leaves
Chambers are opened and closed by ______ differences between chambers.
pressure
Heart valves allow (unidirectional/bidirectional) blood flow.
Unidirectional
Valves that separate atria and ventricles. -mitral and tricuspid valves
Atroventricular valves
Valves that separate ventricles and arteries. -aortic (left) and pulmonary (right) valves
Semilunar valves
T/F: when a ventricle is relaxed it is because atrial pressure > ventricular pressure
-this causes the atrioventricular valve to open
True
T/F: when a ventricle contracts it is because ventricular pressure > atrial pressure
-this causes the atrioventricular valve to close
True
T/F: when a ventricle contracts it is because ventricular pressure > aortic pressure
-this causes the semilunar valve to open
True
T/F: when a ventricle relaxes it is because aortic pressure > ventricular pressure
-this causes the semilunar valve to close
True
Which ventricle is most muscular because it pumps blood to the entire body?
Left Ventricle
_____ branches and carries blood to all organs & tissues in the systematic circuit.
Aorta
If you stop breathing, the build up of _____ kills you before the lack of oxygen does.
CO2
Blood is (oxygenated/deoxygenated) in the organ capillary beds.
deoxygenated
Deoxygenated blood travels back to the heart through the ______ & ______ into the right atrium.
Superior & Inferior Vena Cavas
Pressure is almost always (higher/lower) in the vena cavas than the heart.
higher
Blood in the RIGHT atrium travels through _____ to get to the right ventricle.
tricuspid valve
A healthy heart has:
A. fewer beats and less blood leaving
B. fewer beats and more blood leaving
C. more beats and less blood leving
D. more beats and more blood leaving
B. fewer beats and more blood leaving
-this is because your heart does not have to work as hard.
The only artery to carry deoxygenated blood
Pulmonary artery
Blood in the right ventricle flows through the ______ into the pulmonary artery.
pulmonary semilunar valve
The only oxygenated vein in the body
pulmonary vein
After blood is oxygenated in the lungs, it travels to the ______ through the pulmonary vein.
Left atrium
From the left atrium, blood goes through the _____ into the left ventricle.
Bicuspid / Mitral Valve
Meaning "the heart tells itself to contract"
-the heart contracts without neural input
Myogenic
RHYTHM of the heartbeat is due to activity of ______ & ______.
-pace of the heart
Pacemaker Cells & Conduction Fibers
FORCE of heartbeat is due to activity of _______.
-force of contraction
Contractile Cells
Action Potentials are (longer/shorter) in skeletal muscle cells than cardiac muscle cells.
Longer
Note
Flashcard