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What are the types of muscles? |
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The types of muscles are skeletal, smooth, and cardiac. |
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What are the characteristica of Skeletal muscle? |
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Skeletal muscle is striated and voluntary. |
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What are the characteristics of Smooth muscle? |
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Smooth muscle is NOT striated and is involuntary. |
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What are the characteristics of Cardiac muscle? |
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Cardiac muscle is striated and is involuntary. |
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Define Fascia. |
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Fascia: Layers of connective tissue that seperate individual skeletal muscles and hold in place, seperates the whole muscle from another whole muscle. |
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What are tendons? |
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Tendons are cords that attach muscles to bone. |
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What is the aponeuroses? |
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Aponeuroses is a sheet of connective tissues that attach a muscle to another muscle. |
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Where is the Epimysium located? |
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The epimysium surrounds the entire muscle and is right under the fascia. |
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What is the perimysium? |
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The perimysium is an extension of the epimysium...it extends inward and divides the muscle into compartments. (this is the first stage of compartmentalizing) |
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What are compartments created by the perimysium called? |
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The compartments created by the perimysium are called Fascicles. |
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Where do muscle come from? |
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'Out of the fascicles' comes the muscle fibers. |
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What are the muscle fibers surrounded by? |
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These muscles fibers are surrounded by the endomysium and binds each set to its neighbor. |
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Fill in the blank:
is a complex network, is continuous (even though we call them by different names). |
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Fascia is a complex network, is continuous ( even though we call them by different names). |
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What are the three different 'kinds' of fascia? |
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The three different 'kinds' of fascia are deep, subcutaneous, and suberous. |
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What is the STRUCTURAL hierachy of muscle? |
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The STRUCTURAL hierachy of muscle is muscle-----muscle fiber-----myofibrils-----sarcomere. |
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What is the sarcolemma? |
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The sarcolemma is the cell membrane of a muscle. |
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What is the sarcoplasm? |
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The sarcoplasm is the cytoplasm of the muscle cell. |
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What is the sarcoplasmic reticulum? |
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The sarcoplasmic reticulum is the 'endoplasmic reticulum' of a muscle cell. |
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What type of muscle is multinucleated (many nuclei)? |
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The skeletal muscle is multinucleated (many nuclei) and are usually located near the periphery of the cell. |
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Where are myofibrils loctaed? |
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Myofibrils are in the sarcoplasm. |
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What are the two major protein filaments myofibrils have? |
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Myofibrils have two major types of protein filaments; actin and myosin. |
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What leads to striations in skeletal muscles tissue? |
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It is the arrangement of actin and myosin that lead to the striations of skeletal muscle tissue. |
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Fill in the blank:
The myofibrils contain and ; these filaments give rise to the 'functional unit of contraction' the sarcomere. |
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The myofibril contain actin and myosin; these filaments give rise to the 'functional unit of contraction' the sarcomere. |
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What is the sarcomere defined as? |
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A sarcomere is defined as the area between two 'z lines'. |
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What do 'z lines' look like? |
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Remember: 'z lines' look like a 'zig zag' and that actin attaches to them. |
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How are 'bands or zones' catergorized? |
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'Bands or zones' are categorized based on what they contain ( only myosin, only actin, or overlapping myosin and actin). |
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What is myosin? |
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Myosin is the 'strand' looking protein with the projections called myosin heads. |
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What do these myosin heads do? |
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These myosin heads:
1) form cross bridges that attach to the active site of actin.
2)contain ATPase.
3) are the appendages responsible for the 'power stroke'. |
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What is actin? |
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Actin is the 'helix' molecule and contains the active site where the cross bridges (myosin heads/appendage) attach. |
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Fill in the blank:
The is a network of channels that serve as a reservoir for calcium ions. |
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The sarcoplasmic reticulum is a network of channels that serve as a reservoir for calcium ions. |
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What are transverse tubules? |
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The transverse tubules are invaginations of the sarcolemma (the membrane of a muscle cell), they go deep into the muscle fibers, so the interior of the cell can receive impulses (messages). |
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Generally explain skeletal muscle contraction. |
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In general, skeletal muscle contraction is accomplished by our myrofibrils (actin and myosin) getting an impulse and they slide past each other. |
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When the actin and myosin filaments slide do they shorten? |
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No, remember that when actin and myosin filaments slide, they do NOT shorten, but the sarcomere does. (we remove empty space/ z-lines move closer together.) |
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How are contractions accomplished? |
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To accomplish a contraction the skeletal muscle fibers are stimulated by motor neurons. |
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Where is the neuromuscular junction located? |
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The neuromuscular junction is where the ending of a motor neuron innervates the skeletal muscle i.e. where those two meet. |
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What is a motor end plate? |
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The motor end plate is the portion of the muscle fiber membrane where the sarcolemma is extensively folded. |
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What does the end of a motor neuron contain? |
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The end of the motor neuron (part of the axon) contains vesicles and these vesicles contain neurotransmitters. |
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What is the process of 'sending a message' (impulse) from neuron to muscle? |
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The process of 'sending a message' (impulse) from neuron to muscle: 1)impulse in nerve (action potential) 2)gets to the end of motor neuron 3) causeing the release of the neurotransmitter acetylcholine 4) acetylcholine binds to receptors on the cell membraneof the muscle cell (sarcolemma) 4) this binding activates ion channels that allow certain ions to go through the membrane 6) ions creates an impulse |
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What is the space between the motor neuron ending and the motor plate called? |
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The space between the motor neuron ending and the motor plate is called the synaptic cleft. |
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What does a motor unit consist of? |
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A motor unit consists of muscle fibers and a motor neuron (note that the number of muscle fibers innervated by one motor unit varies by body location). |
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We have an impulse in our muscle fiber, now what happens? |
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1)Impluse is transmitted via the t-tubes into the sarcoplasm 2) sarcoplasmic reticulum 3) SR releases it's storage of calcium ions into the cytosol 4)high concentration of calcium ions 5) troponin-tropomyosin binds to calcium 6)TT complex changes position 7) exposes active site 8)cross bridges can now attach (active site no longer covered up) 9) process of attachment/power stroking/ sliding filaments begins. |
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What does ATP attach to? What does it do? |
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ATP attaches to the myosin providing energy for the cross bridge to attach...serves to 'cock' the myosin cross bridge (remember the head of myosin has ATPase, so it can break that 'high energy' phosphate off the ATP, which gives it the energy.) |
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What are the two steps that must take place for the muscles to relax? |
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The two steps that must take place for the muscles to relax are:
1)ACh needs to be degraded
2)Calcium ions must leave the cytop;asm and go back into the storage area (sarcoplasmic reticulum) Also ATP is required. |
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Fill in the blank:
We USE (by breaking off the phosphate------ADP) for muscle contraction, so we must regenerate from ADP. |
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We USE ATP (by breaking off the phosphate-----ADP) for muscle contraction, so we must regenerate ATP from ADP. |
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How do we regenerate ATP from ADP? |
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We regenerate ATP from ADP by using the phosphate from creatine phosphate (phosphorylating the ADP) |
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What does creatine phosphate serve to do? |
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Creatine phosphate serves to store this phosphate because muscle cells cannot be used by muscle cells |
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What is hemoglobin? |
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Hemoglobin is the pigment in red blood and functions to carry oxygen from the lungs. |
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What is myoglobin? |
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Myoglobin is the pigment in muscle cells and serves to temporarily store oxygen in the muscles. |
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What does the temporary storage of oxygen by myoglobin allow? |
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The temporary storage of oxygen by myoglobin allows for cellular respiration in muscles when they are compressed. |
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What happens if there is an absence of oxygen? |
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In the absence of oxygen pyruvic acid is converted to lactic acid and sent to the liver. |
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What does it take to convert lactic acid into pyruvic acid? |
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It takes energy (ATP) to convert lactic acid back to pyruvic acid AND all ATP is going to the muscles right now -----oxygen debt. |
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What does oxygen debt refer to? |
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Oxygen debt refers to the amount of oxygen needed to covert the accumulated lactic acid back to pyruvic acid (which serves to restore the ATP and creatine phosphate) |
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What happens during muscle fatigue? |
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During muscle fatigue muscles may lose the ability to contract. |
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What can muscle fatigue be caused by? |
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Muscle fatigue can be caused by:
1) decreased blood flow
2) ion imbalances
3) rise in lactic acid |
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What are muscle cramps caused by? |
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Muscle cramps (sustained, involuntary contractions) are typically caused by low concentration of electrolytes. |
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What do athletes produce less of? Why? |
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Athletes produce less lactic acid during strenuous exercise; due to training, new blood capillaries are created and more oxygen and nutrients can get into the muscle fibers. |
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Fill in the blank:
muscles are a major source of heat and help maintain body temperature. |
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Skeletal muscles are a major source of heat and help maintain body temperature. |
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What is the threshold stimulus? |
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The threshold stimulus is the minimal strength required for contraction. |
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What is a refractory period? |
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A refractory period is the brief instant where muscle fibers are unresponsive, 'resetting time'. |
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Explain the concept of the 'all or nothing response'. |
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The concept of the 'all or nothing response' is muscle fiber must be brought to threshold or it will not contract. If brought to threshold, it will contract completely: here increasing stimulus does not affect contraction. |
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What is motor unit recruitment? |
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Motor unit recruitment: low levels of stimulation will only stimulate a few motor units, higher levels will stimulate more (recruiting more to join the contraction). |
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What is the concept of muscle tone? |
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The concept of muscle tone is even at rest, nerve impulses are sending signals to a few muscle fibers; allows for maintenance of posture, sitting, etc. |
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What is an isotonic contraction? |
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Isotonic contractions involve muscle length changes and movement at the joint. |
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What are the two types of isotonic contractions? |
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The two types of isotonic contractions are concentric and eccentric. |
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Define:
concentric |
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Concentric:
muscle shortens. |
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Define:
eccentric |
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Eccentric:
muscle lengthens. |
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What are isometric contractions? |
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Isometric contractions mean that muscle length during contraction and relaxation is about equal; contraction does not produce movement; change in force. |
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Fill in the blank:
Muscle fibers in contraction speed (fast or slow). |
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Muscle fibers vary in contraction speed (fast or slow). |
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What are the characteristics of fast contracting muscles? |
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Characteristics of fast contracting muscles: poor blood supply, fewer mitochondria, larger diameter, use lots of ATP. |
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What are the characteristics of slow contracting muscles? |
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The characteristics of slow contracting muscles: good oxygen supply, lots of mitochondria, smaller diameter, generate ATP quickly. |
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How do skeletal muscles produce movement? |
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Skeletal muscles produce movements by pulling on tendons, which pull on bones. |
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Define:
Orgin |
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Orgin: The part of the muscle that attaches to the nonmoveable bone during contraction. |
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Define:
Insertion |
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Insertion:
The attachment of the muscle to the more moveable bone. |
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What is the prime mover responsible for? |
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The prime mover is responsible for producing a particular movement. |
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What are synergists? |
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Synergists are muscles that assist the prime mover in a particular movement. |
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What is an antagonist? |
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Antagonists are muscles that are relaxed during a movement, but will cause an opposite movement when stimulated. |
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When does multiunit smooth muscle contract? |
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Multiunit smooth muscle contracts only after stimulation by impulses or hormones. |
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What is visceral smooth muscle? |
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Visceral smooth muscle is self-excitatory (cell to cell stimulation); does rythmic contractions that propels substances forwards. |
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What muscle has intercalated discs? |
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Cardiac mucle has intercalated discs, which are located on the ends of the adjacent cardiac muscle cells and serve to hold the cell together. |
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Cardiac muscle has junctions which allows? |
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Cardiac muscle has junctions which allow for the rapid diffusion of ions-----rapids transmission of impulses from cell to cell. |
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What is cardiac muscle? |
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Cardiac muscle is self-excitatory, rhythmic and refractory. |
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