뒤로Anatomy & Physiology Final Exam Study Review
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The four primary tissue types are epithelial, connective, muscle, and nervous tissue.
The three types of muscle tissue are skeletal, cardiac, and smooth muscle.
A skeletal muscle cell is also known as a muscle fiber.
The cell membrane of a skeletal muscle cell is called the sarcolemma.
The cytoplasm of a skeletal muscle cell is called the sarcoplasm.
They are connective tissue layers surrounding muscle: epimysium surrounds the entire muscle, perimysium surrounds fascicles, and endomysium surrounds individual muscle fibers.
A fascicle is a bundle of muscle fibers surrounded by perimysium.
A tendon is a bundle of collagen fibers formed by the merging of epimysium, perimysium, and endomysium that attaches muscle to bone.
An aponeurosis is a broad, flat tendon that attaches muscle to muscle.
Satellite cells are stem cells located between the sarcolemma and endomysium; they function in muscle repair and regeneration.
A myofibril is a long, cylindrical organelle within a muscle fiber composed of repeating sarcomeres responsible for contraction.
The sarcoplasmic reticulum is a specialized smooth endoplasmic reticulum that stores and releases calcium ions for muscle contraction.
T tubules are invaginations of the sarcolemma filled with extracellular fluid that conduct action potentials into the muscle fiber.
A sarcomere is the functional contractile unit of a myofibril, composed of overlapping thick (myosin) and thin (actin) filaments.
Thin filaments are composed mainly of actin, tropomyosin, and troponin; thick filaments are composed of myosin molecules.
During contraction, thin filaments slide past thick filaments, shortening sarcomeres; the H zone and I band get smaller, the zone of overlap increases, and the A band length remains constant.
A neuromuscular junction is the synapse where a motor neuron controls a single skeletal muscle fiber.
Acetylcholine is a neurotransmitter released by motor neurons that binds receptors on the motor end plate, increasing membrane permeability to Na+ and triggering muscle contraction.
Muscle tone is the continuous, passive partial contraction of muscles that helps maintain posture and readiness for action.
Isotonic contractions change muscle length to move a load; isometric contractions generate tension without changing muscle length.
Rigor mortis is the postmortem stiffening of muscles caused by calcium influx and lack of ATP, preventing muscle relaxation.
The nervous system is divided into the central nervous system (CNS) and the peripheral nervous system (PNS).
The PNS is divided into the afferent (sensory) division and the efferent (motor) division.
Neuroglia are supporting glial cells in the nervous system that provide structural support, protection, and nourishment to neurons.
Schwann cells, which form myelin sheaths, and satellite cells, which surround neuron cell bodies in ganglia.
Myelin insulates axons to increase the speed of nerve impulse conduction.
Resting potential is the electrical charge difference across the plasma membrane of a resting neuron, typically around -70 mV.
Calcium ions entering the synaptic terminal trigger the exocytosis of acetylcholine-filled vesicles into the synaptic cleft.