THE STRUCTURE OF THE CARDIOVASCULAR SYSTEM 2015 Thompson Educational Publishing, Inc. 1
250-350g Left of the midline Size of a closed fist Two sides are separated by the septum
The pericardium is the fluid filled sac that surrounds and protects the heart and its great vessels.
Pericardium-protective sac around the heart
The Heart Acts as a Double Pump Myocardium Specialized muscle tissue (cardiac muscle) that forms the heart. The heart is considered a double pump that is divided into right and left sides. Pulmonary circulation The main function of the right side of the heart is to pump deoxygenated blood, which has just returned to the body, to the lungs. Systemic circulation The role of the left side of the heart is to pump oxygenated blood, which has just returned from the lungs, to the rest of the body. 2015 Thompson Educational Publishing, Inc. 8
Arteries and Veins Arteries are blood vessels that carry blood away from the heart. In the systemic circulation, arteries carry oxygenated blood from the left side of the heart towards body tissues. In the pulmonary circulation, arteries carry deoxygenated blood from the right side of the heart towards the lungs. Veins are blood vessels that carry blood towards the heart. In the systemic circulation, veins carry deoxygenated blood towards the right side of the heart from body tissues. In the pulmonary circulation, veins carry oxygenated blood towards the left side of the heart. 2015 Thompson Educational Publishing, Inc. 9
Other Vascular Structures Arterioles Arterioles are vessels in the blood circulation system that branch out from arteries and lead to capillaries, where gas exchange eventually occurs. Capillaries The smallest of the blood vessels, capillaries help to enable the exchange of water, oxygen, carbon dioxide, and other nutrients and waste substances between blood and the tissues of the body. 2015 Thompson Educational Publishing, Inc. 1 0
Overview of the Human Vascular System 2015 Thompson Educational Publishing, Inc. 1 2
Atria and Ventricles Atria and Ventricles The heart is made up of four chambers (two sides). The upper chambers are called atria (singular: atrium ), and the lower chambers are called ventricles. Blood is received into the atria and pushed out from the ventricles. 2015 Thompson Educational Publishing, Inc. 1 3
Major Structures of the Heart 2015 Thompson Educational Publishing, Inc. 1 4
The Flow of Blood through the Heart Blood is delivered to the right atrium from the superior and inferior vena cava. It passes through the tricuspid valve and enters the right ventricle. From there, the blood is pumped through the pulmonary semilunar valve and out through the pulmonary arteries to the lungs. The blood returns from the lungs through the pulmonary veins to the left atrium. It then passes through the bicuspid valve and enters into the left ventricle. The blood is then pumped out through the aortic semilunar valve into the aorta and throughout the systemic circulation. 2015 Thompson Educational Publishing, Inc. 1 5
Tracking the Flow of Blood 2015 Thompson Educational Publishing, Inc. 10
The Skeletal Muscle Pump The low pressure within the veins causes a problem for the cardiovascular system. The skeletal muscle pump aids in the return of blood back to the heart through the veins. With each contraction of the skeletal muscle, blood is pushed back to the heart. 2015 Thompson Educational Publishing, Inc. 20
Pressure in veins (in the chest) decrease while pressure in veins (in the abdominal cavity) increase upon intake of breath Difference in pressure pushes blood from veins in the abdominal cavity into veins in the thoracic cavity
Nervous system sends a signal to the veins to constrict Veins constrict allowing more blood back to the heart
Two main components: Plasma Fluid component of blood (mostly water) Formed Elements Red blood cells (erythrocytes) Made in bone marrow Transport O 2 and CO 2 in the blood Transport nutrients and waste Contain hemoglobin White blood cells (leukocytes) Destroy foreign elements Critical in the function of the immune system Platelets Regulate blood clotting Plasma 55% 90% water 7% plasma proteins 3% other (acids, salts) Buffy Layer Formed elements 45% >99% red blood cells <1% white blood cells and platelets
The Cardiac Cycle The cardiac cycle is the series of events that occurs through one heart beat. During this cycle there is both a phase of relaxation (diastole), in which the ventricle is filling with blood, and a phase of contraction (systole), in which the heart contracts and ejects the blood. Blood pressure is the force exerted by the blood against the walls of the arteries and other vascular vessels. Blood pressure in each of the two phases diastole and systole is measured in millimetres of mercury (abbreviated as mmhg). 2015 Thompson Educational Publishing, Inc. 27
Systolic and Diastolic Blood Pessure When blood pressure is reported or measured, it is often stated as being the systolic pressure over the diastolic pressure (e.g., 120/80 mmhg). Systolic blood pressure refers to the maximum pressure observed in the arteries during the contraction phase of the ventricle (e.g., 120 mmhg). Diastolic blood pressure is the minimum pressure observed in the arteries during the relaxation phase of the ventricle (e.g., 80 mmhg). 2015 Thompson Educational Publishing, Inc. 28
Normal Blood Pressure 120/80 mmhg High Blood Pressure: (hypertension) 140/90 mmhg or higher Low Blood Pressure: (hypotension) 90/60 mmhg
The Heart s Electrical Conduction System The cardiac muscle cells are excitable, meaning that with electrical stimulation they will all contract (this is known as a syncytium ). Within the heart there are areas of specialized tissue that are important in the regulation and coordination of this electrical activity. These specialized tissues are: the sinoatrial node (SA node) the atrioventrical node (AV node) The contraction of the heart leads to the pumping of blood. 2015 Thompson Educational Publishing, Inc. 30
The Heart s Electrical Conduction System The sinoatrial node (SA node) This is a specialized region of tissue that is found in the right atrium where electrical signals that lead to contraction are initiated (also called the pacemaker of the heart). The atrioventrical node (AV node) This is the specialized tissue that transmits the electrical signal from the atria into the ventricles and to a region that runs down the ventricular septum. The ventricular septum is the tissue that separates the two ventricles (the bundle of His, also known as the atrioventricular bundle). 2015 Thompson Educational Publishing, Inc. 20
2015 Thompson Educational Publishing, Inc. 32
Cardiac conduction
An Electrocardiogram 2015 Thompson Educational Publishing, Inc. 35
Measured using an electrocardiogram (ECG) or EKG Graphical representation of electrical sequence of events occurring with each contraction of the heart Current on body surface derived almost entirely form heard 12 tracings or leads
Normal sinus rhythm: 60-100 bpm
Bradycardia: < 60 bpm, conditioned athlete, drugs, hyopothermia, sleeping
Tachycardia: > 100 bpm, exercise, smoking, fever, hypoxia (lack of O2 to brain)
ST segment elevation -represents tissue injury due to acute, prolonged reduction in BF. May show up min or hours after a heart attack (due to clot or vascular coronary spasm)
Inverted T wave: represents ischemia (temporary and reversible reduction in blood flow; may show up hours or days after ischemic attack) Abnormal Q wave: irreversible death of heart tissue
Myocardial infarction: heart attack -occurs when an artery that feeds the heart becomes blocked
Angina: chest pains Ischemia: insufficient blood flow to provide adequate oxygenation. (ischemia leads to hypoxia) Hypoxia: reduction of oxygen supply to tissues Stroke: lack of oxygen to the brain
Heart Rate (HR): is the number of times the heart contracts in a minute (bpm) Avg. HR @ rest =72bpm Highly trained athlete=40bpm During intense exercise HR may increase to up to 200 bpm Maximum HR=220-age
The lowest resting heart beat on record is 28 bpm and belongs to the cyclist Miguel Indura in (Spain) who was tested at the University of Navarra, Pamplona, Spain, in 1995. Lance Armstrong-his heart is 30 percent larger than average; however, an enlarged heart is a common trait for many other athletes. He has a resting heart rate of 32-34 beats per minute (bpm) with a maximum heart rate of 201 bpm.
Activity Speed skater Downhill skier Cyclist Distance runner Sprint athlete Tennis player Shooter Heart Rate 1-Highest 2 3 4 5 6 7-Lowest
Bradycardia and Tachycardia Regular aerobic exercise results in improvements in the efficiency of the cardiovascular system at rest and during exercise. Bradycardia is one of the most easily observed adaptations that occurs with training. Bradycardia is characterized by a heart rate of 60 beats per minute or less at rest, while tachycardia is a heart rate of more than 100 beats per minute at rest. Generally, a lower heart rate is regarded as an indication of an athletic or strong heart. 2015 Thompson Educational Publishing, Inc. 49
The Effects of Exercise During exercise, dramatic changes ocur in the cardiovascular system changes known as cardiovascular dynamics. The heart and the vessels constantly adapt to accommodate the ever-changing requirements of the body during exercise. Some of the factors that are considered when discussing cardiovascular dynamics are: Cardiac output (Q), Blood pressure (BP), Distribution of blood flow, and Oxygen consumption (VO2). 2015 Thompson Educational Publishing, Inc. 50
-Regular aerobic exercise leads to alterations of the cardiovascular system -These are functional & structural With exercise the size and mass of heart increase Ventricular walls become thicker and volume of ventricle increases (due to increase in venous return) This leads to a more forceful contraction= increase in stroke volume= increase in cardiac output
Increase in number of capillaries that deliver blood to the heart tissue Possible increase in the diameter of the coronary arteries increase in O2 to the heart in order to work harder Increase in blood volume up to 15% within 2 days This causes increase in venous return= increase in stroke volume (volume of blood ejected by left ventricle per beat) = increase in cardiac output (the volume of blood pumped out of left ventricle in 1 min) Capillaries around the soleus muscle.
Cardiovascular system adapts to meet the demands that are placed on it Heart adjusts amount of blood pumped by altering: Heart rate (HR) (beats/min) duration of each cardiac cycle Stroke volume (SV) (ml) volume of blood ejected by left ventricle per beat Avg=70 ml per beat Cardiac output (Q) (L/min) HR SV = Q The volume of blood pumped out of left ventricle in 1 min Frank-Starling Law: Ability of the heart to stretch and increase the force of contraction
Q (L/min)=SV (ml) x HR (bpm) Q = SV x HR Eg. An avg. HR at rest would be 72 bpm and an avg. SV at rest would be 71 ml. Therefore using the equation for Q = SV x HR Q= 71mL x 72 bpm Q= 5040 ml/min or 5.04 L/min. During exercise Q can increase to 15-25 L/min depending on the intensity of exercise Athletes tend to have slower HR and large SV creating a more efficient circulatory system. A slower HR with an increased SV requires less oxygen.
Cardiac Output during Exercise 2015 Thompson Educational Publishing, Inc. 55
The Cardiovascular Effects of Training 2015 Thompson Educational Publishing, Inc. 56
Heart Disease The system of vessels that supply essential materials via blood to the heart muscle itself is called the coronary circulation. Serious health repercussions and even death can occur if a narrowing or blockage of blood vessels restricts the flow of blood to the heart muscle. For example, a heart attack (myocardial infarction) can result when blood flow to a section of the heart muscle becomes blocked due to plaque buildup or some other reason. 2015 Thompson Educational Publishing, Inc. 57
The Coronary Vessels (Anterior View) 2015 Thompson Educational Publishing, Inc. 58
Atherosclerosis Coronary artery disease (also known as atherosclerosis) involves a gradual narrowing of the coronary arteries resulting from the accumulation of hard deposits of cholesterol (plaque), on the lining of the blood vessels. 2015 Thompson Educational Publishing, Inc. 59
The Causes of Coronary Artery Disease Poor Diet, Smoking, Elevated blood lipids, Hypertension, Family history, and Physical inactivity. Each factor individually increases the risk of development of coronary artery disease. When the factors are combined, the risk of coronary artery disease is magnified. 2015 Thompson Educational Publishing, Inc. 30
angioplasty
stent
The Functions of the Respiratory System The three main functions of the respiratory system are to: Supply O2 to the blood, Remove CO2 from the blood, and Regulate blood ph (acidbase balance). 2015 Thompson Educational Publishing, Inc. 65
Respiration External Respiration External respiration refers to the processes that occur within the lungs involving the exchange of O2 and CO2. Internal Respiration Internal respiration refers to the exchange of gases at the tissue level, where O2 is delivered and CO2 is removed. Cellular Respiration Finally, cellular respiration is the process in which the cells use O2 to generate energy in the mitochondria of cells. 2015 Thompson Educational Publishing, Inc. 66
The Structure of the Respiratory System The respiratory system can be divided into two main zones the conductive zone and the respirator y zone. The conductive zone transports filtered air to the lungs. This zone consists of the mouth and nose; pharynx; larynx; trachea; primary and secondary bronchi; and tertiary bronchioles and terminal bronchioles. The respiratory zone is where gas exchange occurs. Bronchioles, alveolar ducts, and the alveolar sacs are all structures of the respiratory zone that are involved with the exchange of gases between inspired air and the blood. 67
The Mechanics of Breathing The combination of inspiration and expiration together is known as ventilation. Inspiration is an active process, requiring the contraction of various respiratory muscles and therefore the expenditure of significant amounts of energy. Expiration, on the other hand, may be passive, as in quiet breathing (which may not require much energy) or active (as in forced breathing). 2015 Thompson Educational Publishing, Inc. 68
Inspiration Air flows into the lungs due to increased lung volume following the contraction of the diaphragm and intercostal muscles. 2015 Thompson Educational Publishing, Inc. 40
Expiration Air is expelled from the lungs due to relaxation of the diaphragm and the intercostal muscles. 2015 Thompson Educational Publishing, Inc. 72
Ventilation (V E ) is the volume of air moved by the lungs in 1 min. Influenced by two factors: Tidal volume (V T ) Volume of air in each breath Respiratory frequency (f) Number of breaths taken per minute
Ve is influenced by: V T (tidal volume): vol. of air in each breath f (respiratory frequency): # of breaths taken per min @ rest V T = 0.5 L/breath @ Exercise V T = 4 L/breath @ rest f = 12 breaths/min @ Exercise f = 40 breaths/min Therefore, Ve = V T x f note: during strenuous xcise, Ve = 200 L of air per min
Gas Exchange The average person s lungs have about 300 million alveolar sacs (that is about a tennis court s worth), each of which is surrounded by a web of capillaries. The walls of each capillary are one cell thick, which provides a very short distance for gases to diffuse. 2015 Thompson Educational Publishing, Inc. 75
Diffusion The primar y factor that mediates gas exchange both at the lung (where blood becomes oxygenated and CO2 is removed) and at the tissue (where O2 is delivered for metabolism and CO2 is removed) is diffusion. Diffusion is the movement of a gas, liquid, or solid from a region of high concentration to a region of low concentration through random movement. Diffusion can only occur if a difference in concentration exists, and such a difference is called a concentration gradient. 2015 Thompson Educational Publishing, Inc. 76
O2 Transport O2 Transport The process by which O2 is absorbed in the lungs and carried to the peripheral tissues. CO2 Transport The process by which CO2 in blood is moved into the alveoli and then exhaled from the body. a-vo2 diff The difference between the amount of O2 in the artery and vein reflects the amount of O2 that was delivered to the muscle. 2015 Thompson Educational Publishing, Inc. 77
Monitoring Cardiorespiratory Functioning 2015 Thompson Educational Publishing, Inc. 78
The Rest-to-Exercise Transition The delivery of O2 to the working skeletal muscle is achieved through a combination of physiological mechanisms. However, this is not instantaneous. During this lag, a phenomenon called oxygen deficit (O2 deficit) occurs. Oxygen deficit is the difference between the oxygen required to perform a task and the oxygen actually consumed prior to reaching a new steady state. The trained individual will reach this steady-state plateau faster than an untrained individual. 2015 Thompson Educational Publishing, Inc. 79
Oxygen Deficit: difference between total oxygen consumed during exercise and amount that would have been used at steady-rate of aerobic metabolism.
--Trained person reaches steady-rate quicker, has smaller oxygen deficit.
Light aerobic exercise rapidly attains steady-rate with small oxygen deficit. Moderate to heavy aerobic takes longer to reach steady-rate and oxygen deficit considerably larger. Maximal exercise (aerobic-anaerobic) VO 2 plateaus without matching energy requirement.
Excess post-exercise oxygen consumption: The extra oxygen required to replenish oxygen to the various systems that were taxed during the exercise. Eg: refilling phosphocreatine reserves, replenishing O2 in blood and tissues, lowering breathing rate, lowering body temp. and increasing blood lactate removal. Active recovery can aid in the removal of blood lactate.
O2 Deficit Ventilatory threshold A state in which ventilation increases much more rapidly than workload Lactate threshold The point where blood lactate concentrations begin to increase 2015 Thompson Educational Publishing, Inc. 85
o o o o Ve increases more rapidly than workload 65-85% VO 2 max increase Ve due to increase in lactic acid, and therefore there is a decrease in blood ph (increase in H+ ions in blood) increase in Ve, increases expelling of CO 2 and increases H+ to combine with bicarbonate to form CA CO 2 + H 2 O, therefore decrease in H+ ions increases ph to normal levels, therefore, increase in Ve aids to return blood Ph to normal
Onset of Blood Lactate Accumulation When lactate levels begin to accumulate rapidly in the blood, this is referred to as the onset of blood lactate accumulation (OBLA). With training, the curve for lactate threshold and OBLA can shift to the right. 2015 Thompson Educational Publishing, Inc. 87
VO2max Maximal rate of oxygen consumption (VO2max) VO2max is the maximum volume (V) of oxygen (O2) in millilitres that the human body can use in one minute, per kilogram of body weight, while breathing air at sea level. 2015 Thompson Educational Publishing, Inc. 88
VO2max Scores for Athletes/Non-Athletes 2015 Thompson Educational Publishing, Inc. 89
Physiological Adaptations to Training 2015 Thompson Educational Publishing, Inc. 90
Physiological Adaptations to Training 2015 Thompson Educational Publishing, Inc. 91
Respiratory Diseases Asthma is a disease that is characterized by spasm of the smooth muscles that line the respiratory system, an oversecretion of mucous, and swelling of the cells lining the respiratory tract. Many factors can lead to an asthma attack, including exercise, allergic reaction, contaminates, and stress. Fortunately, most cases of asthma can be controlled through the use of different medications. Some Olympic-level athletes have been diagnosed with asthma and yet are able to compete internationally. 2015 Thompson Educational Publishing, Inc. 60
Asthma Continued In people with asthma, the airways are chronically inflamed. Certain triggers can make the inflammation worse and cause a narrowing of the airways. At the same time, the body may produce extra mucus that clogs the airways. These changes work together to restrict the flow of air to the lungs. As too little air gets through, wheezing and breathlessness occur.
Respiratory Diseases Chronic obstructive pulmonary disease (COPD) is a general term that describes a family of diseases that lead to a dramatic reduction in airflow through the respiratory system. Individuals with COPD cannot perform normal everyday activities without experiencing dyspnea (shortness of breath). Treatment of COPD conditions includes not only medications but also supplemental oxygen therapy for severe cases, as well as respiratory muscle training. 2015 Thompson Educational Publishing, Inc. 94
A Diseased Lung 2015 Thompson Educational Publishing, Inc. 95