BIOH 113 1st EditionExam # 2 Study Guide What is the sequence of excitation in cardiac muscle contraction?Answer: Sinoatrial node  atrioventricular node  atrioventricular bundle right and left bundle branches  purkinje fibers (these are in order from fastest to slowest rhythms)Describe the extrinsic innervation of the heart.Answer: The heart is stimulated by the sympathetic cardioacceleratory center and is inhibited by the cardioinhibitory center. The vagus nerve is the major parasympathetic nerve of the heart.Describe the difference in pressure on the right vs. left side of the heart.Answer: The right side of the heart has a much lower pressure because it does not need to pushblood as far and because of capillary beds.Define cardiac output.Answer: Cardiac output is the amount of blood pumped by each ventricle in one minute. (Cardiac output= heart rate x stroke volume)Which ion allows for more forceful cardiac contractions?Answer: Calcium (Ca2+) allows for more forceful contractions.Describe Frank Starling’s Law.Answer: Frank Starling’s Law states that the output of right and left ventricles is equalized and keeps the same volume of blood pumping to both the pulmonary and systemic circulation.Describe the differences between arteries and veins.Answer: Arteries: carry blood away from heart to supply organs/tissues; have much thicker wallsthan veins; Veins: carry blood back to heart; thinner walls but larger lumen than arteriesIdentify and define the three different types of capillaries.Answer: 1) continuous capillaries: most abundant; make up the blood-brain barrier; have a continuous wall with the only gaps being intracellular clefts2) fenestrated capillaries: found in the kidneys, small intestines, endocrine glands; made up of endothelium with fenestrations(pores)3) sinusoids: leakiest most porous capillaries; found in liver, bone marrow; allow large moleculessuch as proteins and blood cells to pass throughDefine vaso vasorum.Answer: Vaso vasorum are small blood vessels that supply the walls of large blood vessels—large arteries and veins.Are merging blood vessels more common in arteries or veins?Answer: Merging blood vessels are more common in veins.What are the main factors influencing blood pressure?Answer: The main factors influencing blood pressure are cardiac output, peripheral resistance and blood volume.Identify the 3 ways in which substances can travel in and out of capillaries by.Answer: 1) Diffusion: substances travel down their concentration gradient2) Transcytosis: substances become enclosed in endothelial cells and are then exocytized to the other side3) Bulk flow: pressure is the driving force—large numbers of solutes move together in the same direction Identify the 8 pulse/pressure points.Answer: superficial temporal artery; facial artery; common carotid artery; brachial artery; radial artery; femoral artery; popliteal artery; dorsal artery of the footDefine Korotkoff sounds.Answer: Korotkoff sounds are the various sounds heard while taking blood pressure (usually with a sphygmomanometer. What structure in veins prevents backflow of blood?Answer: Valves in veins prevent backflow of blood.Look over and be able to identify the main veins and arteries in the body. GOOD LUCK