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109 Cards in this Set
- Front
- Back
_______ or ________ is a type of connective tissue. Just like other connective tissues, it is made up of cells and matrix
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Bone, or Osseous tissue
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Externally, a bone is covered with a sheath called the
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periosteum
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The internal surface of a bone is lined
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endosteum
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The four types of cells found in osseous tissue are the
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osteogenic cells, osteoblasts, osteocytes, and osteoclasts
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Osteogenic cells are the ________ that undergo mitosis and differentiate into osteoblasts
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stem cells
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Osteoblasts
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bone-forming cells
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Osteocytes
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are mature osteoblasts that have become stuck in their own matrix
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Osteoclasts
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are bone-dissolving cells
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organic matter
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is synthesized by the osteoblasts
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osteoblasts includes
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collagen, glycosaminoglycans, proteoglycans, and glycoproteins
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inorganic matter consists mainly of
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hydroxyapatite
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There are two kinds of bone marrow
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red and yellow
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Red bone marrow is
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hemopoietic (blood producing)
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Yellow marrow consists mainly of
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adipose tissue and is not hemopoietic (blood producing)
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The formation of bone is called
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ossification or osteogenesis
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Bone develops by two methods,
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intramembranous and endochondral ossification
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Intramembranous ossification
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produces the flat bones of the skull and most of the clavicle
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All of our other bones are formed by
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endochondral ossification
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bone develops from a preexisting model composed of
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hyaline cartilage
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Resorption
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is the process of dissolving bone and returning its minerals to the bloodstream
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Bone resorption is carried out the
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osteoclasts
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__________ is a crystallization process in which calcium, phosphate, and other are ions taken from the blood plasma and deposited into the skeleton
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Mineralization
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Mineralization
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is carried out by the osteoblasts.
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A calcium deficiency in the blood is called
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hypocalcemia
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Hypocalcemia causes
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excessive excitability of the nervous system (leads to muscle tremors, spasms, or tetany)
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_______ is the inability of a muscle to relax.
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Tetany
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An excess of calcium in the blood is called
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hypercalcemia
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Hypercalcemia causes
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depression of the nervous system (muscle weakness, sluggish reflexes, and sometimes cardiac arrest)
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Calcium homeostasis is regulated by three hormones
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calcitriol, calcitonin, and parathyroid hormone
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calcitriol, calcitonin, and parathyroid hormone
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increase the blood calcium concentration
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calcitonin
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lowers the blood calcium concentration
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These hormones use different methods to raise or lower the blood calcium levels such as increasing or decreasing osteoblast or osteoclast activity, increasing calcium absorption by the small intestine, and promoting the reabsorption of calcium ions by the kidneys so less calcium is lost in the urine
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calcitriol, calcitonin, and parathyroid hormone
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if a hormone increases osteoblast activity
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blood calcium levels will decrease (Because osteoblasts are bone forming cells)
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if a hormone decreases osteoblast activity
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cause blood calcium levels to increase (Because less calcium is being taken from the blood and deposited into the skeleton)
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Increasing calcium absorption by the small intestine
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causes blood calcium levels to increase
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Promoting or increasing the reabsorption of calcium ions by the kidneys cause
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blood calcium levels to increase because less calcium is lost in the urine
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Abnormal calcification of tissues is called
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ectopic ossification
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A calcified mass in an otherwise soft organ is called a
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calculus
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literally means “porous bones.”
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Osteoporosis
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Postmenopausal white women are at the greatest risk
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lack of estrogen
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Any point where two bones meet is called a
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joint, or articulation.
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The study of joint structure, function, and dysfunction is called
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arthrology
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There are four kinds of joints;
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bony, fibrous, cartilaginous, and synovial
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the adjacent bones are bound by collagen fibers that emerge from one bone, cross the space between them, and penetrate into the other
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fibrous joint
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bind the bones of the skull together
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Sutures
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The attachment of a tooth to its socket is a
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gomphosis
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___________ the two bones are bound by longer collagenous fibers
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syndesmosis
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The most familiar type of joint is the
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synovial joint
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In synovial joints, the facing surfaces of the two bones are covered
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with articular cartilage.
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These surfaces are separated by a narrow space, the
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joint cavity
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Within the joint cavity is a slippery lubricant called
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synovial fluid
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A connective tissue ___________ encloses the cavity and retains the fluid
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joint (articular) capsule
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It has an outer __________ continuous with the periosteum of the adjoining bones, and an inner, cellular _________
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fibrous capsule, synovial membrane
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The synovial fluid is secreted by fibroblast-like cells of the synovial membrane.
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Synovial fluid nourishes the articular cartilages, removes waste from the articular cartilages, and lubricates the joint for almost friction-free movement.
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A ________ is a fibrous sac filled with synovial fluid, located between adjacent muscles, where a tendon passes over a bone, or between bone and skin.
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bursa
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The plasma membrane of a muscle fiber is called the _________ and its cytoplasm is called the _________
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sarcoplasm, sarcoplasm
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Within the sarcoplasm are
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myofibrils, glycogen, and myoglobin.
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The smooth endoplasmic reticulum of a muscle fiber is called the
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sarcoplasmic reticulum
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The sarcoplasmic reticulum is a
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reservoir of calcium ions
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It forms a network around each myofibril and has dilated end-sacs called
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terminal cisternae
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The sarcolemma has tubular infoldings called
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transverse (T) tubules,
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T tubule and the two terminal cisternae associated with it
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constitute a triad
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Each myofibril is a bundle of protein microfilaments called
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myofilaments
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There are three kinds of myofilaments
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thick, thin, and elastic
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Thick filaments are made of several hundred molecules of a protein called
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myosin
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Thin filaments are composed mainly of two intertwined strands of a protein called
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fibrous (F) actin
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Each fibrous (F) actin is made up of monomers of
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globular (G) actin
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thin filament also has 40 to 60 molecules of another protein called
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tropomyosin
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Tropomyosin blocks the active sites of G actin in a relaxed muscle fiber. Each tropomyosin molecule has a small calcium-binding protein called
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troponin bound to it
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Elastic filaments are made of a huge springy protein called
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titin (connectin)
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Myosin and actin are called
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contractile proteins
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Tropomyosin and troponin are called
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regulatory proteins
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Each segment of a myofibril from one _______ to the next is called a _______
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Z disc, sarcomere.
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One nerve fiber and all the muscle fibers innervated by it are called a
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motor unit
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_________ is the neurotransmitter responsible for stimulating the muscle fiber.
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Acetylcholine
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Acetylcholine is released from
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the synaptic knob
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When Acetylcholine is done stimulating a muscle fiber it is broken down by the enzyme
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Acetylcholinesterase
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In an ________ there are more anions on the inside of the plasma membrane than on the outside.
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unstimulated (resting) cell,
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Thus the plasma membrane is electrically
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polarized
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This is referred to as the
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Resting Membrane Potential (RMP)
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When a muscle fiber is stimulated ion gates in the plasma membrane open and
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Na+ diffuses down its concentration gradient into the cell
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This causes the inside of the plasma membrane to briefly become positive. This change is called
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depolarization of the membrane
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Na+ gates eventually close and K+ gates open. K+ diffuses
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out of the cell down its concentration gradient
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The loss of positive potassium ions from the cell turns the inside of the membrane negative again
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repolarization
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The calcium ion gates on the synaptic knob are
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voltage-regulated. They open and close in response to changes in voltage (action potentials)
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The acetylcholine receptor ion gates of the sarcolemma are
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ligand-regulated
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Muscle contraction or tension without a change in length is called
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isometric contraction.
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Muscle contraction with a change in length but no change in tension is called
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isotonic contraction
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muscle shortens as it maintains tension
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isotonic concentric contraction
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a muscle lengthens as it maintains tension.
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isotonic eccentric contraction
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There are two pathways for ATP synthesis
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aerobic respiration and anaerobic fermentation
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produces lactic acid as an end product
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Anaerobic fermentation
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In the absence of oxygen a cell must get it’s ATP by this pathway
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Lactic acid is a major contributor to muscle fatigue
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In a short, intense exercise such as 6 seconds of sprinting the
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phosphagen system supplies most of the ATP
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There are two physiological classes of muscle fibers,
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slow oxidative and fast glycolytic.
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Slow oxidative fibers are also called
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slow-twitch, red, or type I
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Fast glycolytic fibers are also called
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fast-twitch, white, or type II fibers
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_________ depends on a variety of anatomical and physiological factors including
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Muscular strength, muscle size, fascicle arrangement, and size of active motor units
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Skeletal muscle cells, cardiac muscle cells, and smooth muscle cells may also be called
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myocytes
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Cardiac muscle cells are also called
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cardiocytes
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Each cardiocyte is joined to other cardiocytes through linkages called
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intercalated discs
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These intercalated discs contain _______ that allow each cardiocyte to directly stimulate its neighbors, and _______ that keep the cardiocytes from pulling apart when the heart contracts.
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electrical gap junctions, mechanical junctions
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The intercalated discs histologically appear as thick dark lines in stained tissue sections. Cardiac muscle is highly resistant to fatigue because it uses
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aerobic respiration almost exclusively
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Muscle contraction in skeletal, cardiac, and smooth muscle is triggered by calcium ions, although in smooth muscle the calcium ions come mainly from the
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extracellular fluid by way of calcium ion channels in the sarcolemma.
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There are two functional categories of smooth muscle,
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multiunit and single-unit.
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________ smooth muscle is more widespread than multiunit smooth muscle.
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Single-unit
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Smooth muscle cells are
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fusiform
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Even though smooth muscle cells contain thick and thin myofilaments, they are not aligned with each other and therefore produce
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no visible striations.
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Since we do not have conscious control over smooth muscle, it is described as
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involuntary
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