exam 3Versión en línea 45 questions por a. G. 1 Cross-bridge formation occurs when myosin heads attach to actin molecules located in the thin filaments. a True b false 2 A cell is only able to respond to hormones if specific hormone receptors are present on the membrane or within the cell. a True b False 3 The _______________________ autonomic division is dominant in an emergency situation. a Sympathetic b Fight or flight c Motor unit d hormones 4 When two or more hormones work together to produce a particular result, their effects are_________. a Antagonistic b Permissive c Synergistic d Inhibitory 5 Cardiac output is equal to_________. a stroke volume / cardiac rate b stroke volume − cardiac rate c stroke volume × cardiac rate d stroke volume + cardiac rate 6 Transverse tubules contain voltage-gated calcium channels that respond to membrane depolarization, and are directly coupled to the calcium release channels in the sarcoplasmic reticulum. a true b False 7 Thin filaments are composed of myosin and tropomyosin. a False b True 8 The circulatory system is able to provide regulation of other body systems by circulating_________. a Hormones b Clotting 9 Each somatic motor neuron and all of the muscle fibers it innervates is called a ________ a Hormones b Motor unit c synergistic d Neuromuscular junction 10 Hormones released from the adrenal medulla prolong and enhance the fight or flight response. a False b true 11 The amount of blood ejected by the ventricles per beat is termed the_________. a cardiac output b end-diastolic volume c blood pressure d stroke volume 12 Which of the following is a catecholamine? a Nitric oxide b Acetylcholine c All of the choices are correct. d Norepinephrine 13 For muscle contraction to occur, ATP and its hydrolyzed forms are needed for the_________. a pumping of Ca2+ back into the sarcoplasmic reticulum b attachment of myosin cross-bridges to actin c All of the choices are correct. d release of myosin cross-bridges from actin 14 Systole refers to the_________ of the ventricles, when pressure is_________. a relaxation; lowest b blood flow; lowest c filling; highest d contraction; highest 15 Closure of the atrioventricular valves occurs at the end of diastole/beginning of systole. a False b True 16 "Synapses en passant" refers to the fact that postganglionic autonomic neurons release neurotransmitter_________. a from the axon terminal b along the length of the axon c from the soma d only when receptors pass over the axon 17 The posterior pituitary gland_________. a releases its hormones in response to stimulation by hormones from the hypothalamus b synthesizes oxytocin, which plays a vital role in inducing labor c releases hypothalamic hormones, but does not produce its own d regulates the secretion of hormones produced in the anterior pituitary gland 18 Cortisol secretion would cease if the_________ no longer secreted ACTH. a anterior pituitary gland b adrenal cortex c posterior pituitary gland d Hypothalamus 19 What protein primarily makes up the thick filament? _________________ a Pituitary gland b Acetylcholiine c Titin d Myosin 20 Norepinephrine is released from_________ neurons, causing heart rate to_________. a sympathetic; increase b parasympathetic; increase c sympathetic; decrease d parasympathetic; decrease 21 What is the function of antidiuretic hormone (ADH)? a Stimulates retention of water by the kidneys b Causes a darkening of the skin c Stimulates loss of water by the kidneys d Causes large urine volume 22 Cardiac output increases as heart rate increases. a false b true 23 Slow-twitch fibers have a________ oxidative capacity and________ glycogen content. a high; high b low; low c high; low d low; high 24 Which molecule blocks the myosin head from binding to actin in a relaxed muscle? a Calcium b Troponin c Tropomyosin d Titin 25 What element is necessary for production of thyroxine? a Calcium b Chlorine c Iodine d Sodium 26 Increased motor unit recruitment causes_________ force generation by a muscle. a decreased b no change in c Increased 27 The movement of the troponin-tropomyosin complex requires_________. a Na+ b ATP c Ca2+ d acetylcholine 28 The molecules secreted by endocrine glands that are inactive until changed by their target cells are_________. a tissue hormones b Prohormones c lipophilic hormones d prehormones 29 Somatic motor neurons release the neurotransmitter_________ at the neuromuscular junction. a Serotonin b Norepinephrine c acetylcholine d Dopamine 30 What is the structural and functional unit of skeletal muscle? a Myofibril b Sarcomere c A band d I band 31 Cardiac_________ channels are called hyperpolarization cyclic nucleotide (HCN) channels because they open in response to hyperpolarization. a Purkinje b Atrial c pacemaker d Ventricular 32 A deficiency of dietary iodine would result in excessive TSH secretion. a false b true 33 Somatic motor reflexes may result in_________. a contraction of skeletal muscle b inhibition of smooth muscle contraction c contraction of smooth muscle d Vasoconstriction 34 The vascular link between the hypothalamus and the_________ is called the hypothalamo-hypophyseal portal system. a thalamus b pineal gland c anterior pituitary d posterior pituitary 35 Some glands throughout the body have both endocrine and exocrine functions. a false b true 36 As cardiac muscle is stretched, it contracts less forcibly. a false b true 37 What structures carry the action potentials into the interior of the muscle to cause muscle contraction? a Ryanodine receptors b Terminal cisternae c Sarcoplasmic reticula d T tubules 38 Most of the circulating blood can be found in_________. a Capillaries b Arterioles c Veins d arteries 39 The pancreas secretes hormones involved in the regulation of_________. a growth and reproduction b metabolic rate c blood glucose d the stress response 40 Most target organ control on the anterior pituitary gland is due to_________. a negative feedback b negative feedback inhibition c positive feedback inhibition d positive feedback effect 41 Blood flow is increased by_________. a vasodilation b vasoconstriction c edema d hypotension 42 Transportation functions of the circulatory system include carrying_________. a leukocytes b metabolic waste c All of the choices are correct. d absorbed products of digestion 43 In skeletal muscle, the pumps that actively transport calcium back into the_________ are called Ca2+-ATPase pumps. a sarcoplasmic reticulum b transverse tubules c neuromuscular junction d None of the choices are correct. 44 Endocrine glands secrete their products into ducts. a true b false 45 What part of the heart's conduction system acts as the primary pacemaker? a Atrioventricular (AV) node b Bundle of His c Purkinje fibers d Sinoatrial (SA) node
