Anatomy Chapter 9 Flashcards

A tendon is a projection of connective tissue beyond the ends of the muscle that attaches to bone. An aponeurosis is a broad fibrous sheet of connective tissue that connects muscles to adjacent muscles.

Muscle fibers are grouped together in fascicles that are surrounded by endomysium. The fascicles are bundled together and surrounded by perimysium. The entire muscle is covered by epimysium.

Deep fascia surrounds and penetrates muscles. Subcutaneous fascia lies just beneath the skin. Subserous fascia forms the connective tissue layer of serous membranes covering organs.

<p>A muscle fiber has a sarcolemma (cell membrane), sarcoplasm (cytoplasm), myofibrils (threadlike proteins), sarcomeres (segments of myofibrils), sarcoplasmic reticulum (network of channels), and transverse tubules (invaginations for stimulation).</p> Signup and view all the answers

<p>The neuromuscular junction is the site where a nerve fiber communicates with a muscle fiber, allowing for muscle contractions via stimulation.</p> Signup and view all the answers

<p>A neurotransmitter is released into the gap at the motor end plate when stimulated, which stimulates the muscle fiber to contract.</p> Signup and view all the answers

<p>Skeletal muscle contraction involves the sliding movement of actin and myosin filaments due to muscle parts and chemical substances.</p> Signup and view all the answers

<p>ATP supplies energy for muscle contraction, while creatine phosphate acts as an energy reservoir for ADP.</p> Signup and view all the answers

<p>Oxygen is carried by hemoglobin in the blood and transferred to myoglobin in muscle fibers.</p> Signup and view all the answers

<p>Oxygen debt occurs when skeletal muscles exceed their oxygen reserves, leading to anaerobic respiration and lactic acid accumulation.</p> Signup and view all the answers

<p>Muscle fatigue occurs from prolonged strenuous exercise, often due to lactic acid accumulation, diminished blood supply, or acetylcholine depletion.</p> Signup and view all the answers

<p>The threshold stimulus is the minimal strength of stimulus required to trigger a muscle fiber response.</p> Signup and view all the answers

<p>A twitch is a single muscle fiber contraction, while sustained contraction involves multiple action potentials leading to increasing contraction strength.</p> Signup and view all the answers

<p>A motor unit consists of a motor neuron and the muscle fibers it controls; fewer fibers allow for more precise movements.</p> Signup and view all the answers

<p>Recruitment is the increase in the number of activated motor units as stimulation intensity increases.</p> Signup and view all the answers

<p>A muscle can sustain contraction when stimuli increase in frequency to prevent complete relaxation before the next stimulus.</p> Signup and view all the answers

<p>Tetanic contraction is a sustained forceful contraction without relaxation, while muscle tone maintains posture through small, repeated contractions.</p> Signup and view all the answers

<p>Isotonic contractions involve muscle shortening, while isometric contractions occur with tension without movement.</p> Signup and view all the answers

<p>Fast-twitch fibers contract rapidly and fatigue quickly, while slow-twitch fibers are fatigue-resistant, supporting prolonged activity.</p> Signup and view all the answers

<p>Multiunit smooth muscle consists of separate fibers and requires nerve impulse stimulation, while visceral smooth muscle has interconnected fibers capable of stimulating each other.</p> Signup and view all the answers

<p>Peristalsis consists of alternating contractions and relaxations of muscle fibers, forcing contents along a tube.</p> Signup and view all the answers

<p>Both types use actin and myosin, triggered by membrane impulses, but skeletal muscle uses acetylcholine, while smooth muscle uses both acetylcholine and norepinephrine.</p> Signup and view all the answers

<p>Skeletal muscle contracts individually, while cardiac muscle works in a coordinated network and occurs only in the heart.</p> Signup and view all the answers

<p>A lever has a rigid rod, fulcrum, resistance, and force. First-class: resistance-fulcrum-force; Second-class: fulcrum-resistance-force; Third-class: resistance-force-fulcrum.</p> Signup and view all the answers

<p>Limb movements act as levers by utilizing rigid bars, pivots, resistance, and force.</p> Signup and view all the answers

<ol> <li>Decline in myoglobin, ATP, and creatine. 2) Muscles become smaller and drier. 3) By age 80, half of muscle mass may be atrophied.</li> </ol> Signup and view all the answers

<p>Exercise can promote muscle growth, maintain blood pressure, and enhance oxygen levels and endurance.</p> Signup and view all the answers