The Purkinje fibresc) The atrioventricular node (AVN)d) The sinoatrial node (SAN)6 Angina pectoris is usually associated with occlusion ofa) The aortab) The coronary arteriesc) The carotid arteriesd) The pulmonary arteries
7 Which of the following blood vessels do not carry oxygenated blood?a) The pulmonary veinsb) The coronary arteriesc) The aortad) The pulmonary arteries
8 The major baroreceptors that continually measure arterial blood pressure are located ina) The vena cavaeb) The pulmonary arteriesc) The jugular veinsd) The aortic arch and carotid sinuses
9 Antidiuretic hormone (ADH), which is also known as vasopressin, is released whena) Blood pressure decreasesb) The blood is diluted by drinking too much waterc) The kidneys need to eliminate calcium (Ca)d) Blood pressure increases
10 Which of the following statements relating to the renin angiotensin aldosterone system (RAAS) is true?a) The system is activated when blood pressure is highb) Angiotensinogen is produced by the kidneyc) Angiotensin-II is a powerful vasoconstrictord) Renin is produced by the liver
Chapter summary
The cardiovascular system, consisting of the heart and blood vessels, functions as the major transport system. Blood acts as the transport medium and is continually circulated throughout the body in the blood vessels. Arteries are muscular, thick-walled vessels that usually carry oxygenated blood under high pressure away from the heart, while veins are thin-walled blood vessels equipped with valves that usually carry deoxygenated blood under low pressure towards the heart.
Capillaries are the smallest blood vessels and found in complex networks termed capillary beds which permeate the tissues of the body and function to distribute blood. The right-hand side of the heart pumps deoxygenated blood to the lungs via the pulmonary circuit, while the left-hand side pumps oxygenated blood to all other areas (organ systems) via the systemic circuit. The heart is anchored in a relatively central position within the thorax (retrosternal) and protected by a compound membrane termed the pericardium. To function as an efficient pump, the chambers of the heart contract and relax in a five-phase sequence termed the cardiac cycle.
The events of the cardiac cycle are precisely timed and coordinated by the cardiac conductive system. The electrical activity of this system can be recorded on an electrocardiogram. Blood pressure (BP) is a product of cardiac output (CO) and the peripheral resistance (PR) afforded by the blood vessels (BP = CO × PR). Ideally, blood pressure is maintained at around 120/80 mmHg by a combination of neural and hormonal mechanisms.
Activities: Brief outline answers
Activity 3.1: Research and revision (page 55)
Sequence of blood flow through major blood vessels of the heart:
Vena Cavae → Right Atrium → Tricuspid Valve → Right Ventricle → Pulmonary Artery → Pulmonary Valve → Lungs → Pulmonary Veins → Left Atrium → Bicuspid Valve → Left Ventricle → Aortic Valve → Aortic Arch
You may find it useful to make up a mnemonic or other memory aid to help remember this sequence.
Activity 3.2: Communication (page 63)
Atrial fibrillation (AF) is an arrhythmia that becomes increasingly common with advancing age. During AF the atria will be contracting rapidly and in an uncoordinated manner, which can result in poor ventricular filling. AF is often asymptomatic when at rest since 70 per cent of ventricular filling occurs passively; however, Gerald has been experiencing symptoms of breathlessness during exercise (when gardening and walking upstairs). It is during exercise that the full filling of the ventricles becomes increasingly important.
With AF the final 30 per cent of ventricular filling may not occur and as a result the cardiac output (CO) may fall, leading to the breathlessness Gerald is experiencing. AF can cause turbulent blood flow in the atria, increasing the risk of thrombosis. It is almost certainly a mobile clot (embolus) that has caused the stroke which Gerald has just suffered. Although Gerald has not recently been compliant in taking his medication, as a nurse it is vital to reinforce how essential apixiban is to managing his AF since it is this medication that will reduce the chances of clots forming and further strokes occurring.
Activity 3.3: Critical thinking (page 70)
Based on Gloria’s prior history, it is clear that she has long-standing coronary artery disease. This would explain why she has experienced chest pain during exertion which is indicative of angina. Her past history of infarction indicates that portions of her heart muscle (myocardium) have been damaged. This new issue of swollen ankles and feet is worrying since peripheral oedema is a clinical feature of right-handed heart failure.
It may be that despite having stents fitted, Gloria has suffered further infarctions or the damage caused by the previous infarctions is gradually reducing the ability of the right-hand side of the heart to collect venous blood and pump it through the lungs. These new symptoms will need careful assessment to determine if any further interventions or new medications are needed to manage Gloria’s heart problems.
Activity 3.4: Evidence-based practice and research (page 73)
Janet has experienced postural hypotension which has caused her fainting episode. On standing, blood pressure (BP) will fall as gravity pulls blood downwards. This drop is usually quickly detected by the baroreceptors and the heart rate is increased, and blood vessels undergo vasoconstriction to maintain BP. This baroreceptor response tends to become less efficient (blunted) with age. Janet takes a combined beta blocker and diuretic pill to treat her hypotension and this could significantly increase the risk of postural hypotension.
The beta blocker component slows Janet’s heart rate reducing her cardiac output while the diuretic will increase urine production, lowering Janet’s blood volume. Janet will require further assessment to determine if there are any other underlying causes for her postural hypotension. Based on this episode, Janet should be advised to rise slowly to allow her BP to normalise and she may have to be switched to a different type of antihypertensive medication.
Activity 3.5: Multiple-choice questions (pages 77–9)
1) c, 2) a, 3) b, 4) c, 5) d, 6) b, 7) d, 8) d, 9) a, 10) c
Further reading
Boore J et al. (2016) Chapter 12: The cardiovascular and lymphatic systems, in Essentials of Anatomy and Physiology for Nursing Practice. London: SAGE Publications Ltd.
A textbook to develop your knowledge of human anatomy and physiology that is aimed specifically at nurses.
Tortora G and Derrickson B (2017) Tortora’s Principles of Anatomy and Physiology (15th edition). New York: John Wiley & Sons.
In-depth coverage of human anatomy and physiology.
Useful websites
www.nhs.uk/conditions/arrhythmia
A simple overview of arrhythmias.
