Bio 256 Final Complete Exam 2025

Bio 256 Final Complete Exam 2025 Which of the following surrounds a bundle of myofibers? - -Perimysium In skeletal muscle, each myofiber is surrounded by - -Endomysium. The first thing that stops a muscle contraction after a motor neuron stops sending ACh is: - -Actylcholinesterase destroys the ACh as it is removed from membrane receptors. The sliding filament model of contraction involves - -Actin and myosin sliding past each other but not shortening. Muscle tone is - -A state of sustained partial contraction of muscles. Which of the following are composed of actin - -Thin filaments. Muscle cells work together in groups known as motor units. These consist for a motor neuron and - -the muscle fibers innervated by it When a muscle fiber is stimulated by acetylcholine,-- channels on the plasma membrane open - -Na+ The number of muscle fibers in a contracted state in an otherwise relaxed muscle is known as its - -Muscle Tone In an isometric contraction, muscles - -stay the same length When a muscle is temporarily unable to respond to stimuli, it is in which of the following periods - -refractory period Myoglobin - -holds a reserve supply of oxygen in muscle cells Which serves as a quick source to replete ATP in exercising muscle - -creatine phosphate Smooth muscle is significantly different from striated muscle in several ways. Which of the following is true - -smooth muscle can shorten and stretch more than striated muscle Which is not a function of blood - -synthesis of hormones Which of these is not a normal plasma protein - -hemoglobin Bio 256 Bio 256 Formed elements found in the blood that are about 7-8 Um in diameter with no nuclei are - -erythrocytes What organ in the body regulates erythrocyte production - -kidney When red blood cells wear out, the iron of hemoglobin is saved and recycled. The remained of the heme is - -excreted as bile pigments James has a hemoglobin measurement of 15 g/100 ml blood. This is - -within the normal range Sicking of red blood cells can be produced in those with sickle-cell anemia by - -travel at high altitudes Which of the following is a precursor of a basophil - -myeloblast Which of the following represents a normal differential count in a healthy adult - -65% neutrophils, 25% lymphocytes, 6% monocytes, 3% eosinophils, 1% basophils Which blood cells orchestrate the complex interactions of cell functions in the immune system, allowing the body to eliminate infections - -T-lymphocytes Acute leukemia is more common in--- persons; chronic leukemia is more common in--- persons - -younger, older Which is not made and released by activated platelets as they plug damaged blood vessels and initiate tissue repair - -prostacyclin The conversion of soluble fibrinogen into insoluble fibbing required direct enzymatic conversion by - -thrombin Which is an anticoagulant protein that can dissolve clots, thus limiting their size to that necessary? This protein is made as needed from an inactive precursory in plasma - plasmin Which of the following is not a cause of bleeding disorders - -excess secretion of platelet-derived growth factor (PDGF) Initiation of a cardiac action potential in contracting cardiac muscle cells begins with - opening voltage-gated fast sodium channels Cardiac ischemia can result in - -a myocardial infarction Which of the following is not part of the conduction system of the heart - -AV valve Input from the sympathetic nervous system causes the heart rate to - -Increase Bio 256 Bio 256 The time from when the ventricular contractile myofibers are depolarized until they depolarize is represented by the - -S-T interval The first heart sound is caused by the - -closure of the mitral and tricuspid valves The dicrotic notch refers to the - -brief rise in aortic pressure caused by back flow of blood rebounding off the aortic semilunar valve An increase in venous return most directly affects - -stroke volume Normal cardiac output is about-- L/min - -5.2 Which provides a positive chronotropic effect on the heart - -norepinephrine Angina pectoris is - -Pain accompanying myocardial ischemia. Skeletal muscle assists the heart in moving blood through - -Veins The influence of blood vessel diameter on peripheral resistance is - -Significant because resistance is inversely proportional to the fourth power of the vessel radius. Which is the correct equation for the relationship between blood pressure cardiac output and peripheral resistance - -BP=COxPR Which will increase blood pressure - -antidiuretic hormone Which is not a vital sign used to asses the cardiovascular system - -serum cholesterol Blood pressure peaks each day - -in the morning Which of the following is likely during vigorous exercise - -capillaries of the active muscles will be engorged with blood The major targets of growth hormone are - -bones and skeletal muscles. The parathyroid glands maintain adequate levels of blood calcium. Parathyroid hormone does this by - -Activating osteoclasts so that calcium will be released from bone Each muscle fiber is stimulated by a nerve ending known as a(n) - -motor end plate. Regulating hormones from the hypothalamus - -first enter into the hypophyseal portal system. Which of the following surrounds the individual muscle cell - -Endomysium Bio 256 Bio 256 The first thing that stops a muscle contraction after a motor neuron stops sending ACh is - -acetylcholinesterase destroys the ACh as it is removed from the membrane receptors Calcium ions bind to--- in skeletal muscle cells - -Troponin The warm-up period required of athletes in order to brin