Exercise Science Section 7: The Cardiovascular and Respiratory Systems

Transcription

1 Exercise Science Section 7: The Cardiovascular and Respiratory Systems An Introduction to Health and Physical Education Ted Temertzoglou Paul Challen ISBN

2 The Cardiovascular System Composed of: v Heart v Blood vessels v Blood Functions: v Delivery of O 2, fuel, and nutrients to the tissues of the body v Removal of CO 2 and waste products from the tissues v Maintenance of a constant body temperature (thermoregulation) v Prevention of infection (immune function)

3 The Heart Formed from myocardium, a specialized muscle tissue Surrounded by pericardium (tough protective sac); allows heart to expand and contract Epicardium lines outside of heart; endocardium lines inside of heart Made up of four separate chambers: atria (upper chambers) and ventricles (lower chambers) Considered a double-pump and is divided into the right and left heart; separated by the interventricular septum v Right heart: } pumps deoxygenated blood to the lungs (pulmonary circulation) v Left heart: } Pumps oxygenated blood to the rest of the body (systemic circulation)

4 Structures of the Heart Common Structures Structure of right side Structure of left side Chordae tendinae Superior and inferior vena cava Aorta and thoracic (descending aorta) Papillary muscles Right atrium Left atrium Interventricular septum Right ventricle Pulmonary artery Left ventricle Pulmonary vein Tricuspid valve Bicuspid (mitral) valve Pulmonary valve Aortic valve

5 The Internal Anatomy of the Heart Aorta Superior vena cava Left pulmonary artery Right pulmonary artery Aortic semilunar valve Left pulmonary veins Right pulmonary veins Pulmonary semilunar valve Right atrium Interventricular septum Tricuspid valve Right ventricle Inferior vena cava Left atrium Bicuspid (mitral) valve Left ventricle Chordae tendinae Papillary muscles Chordae tendinae Papillary muscles Thoracic aorta (descending)

6 Path of Blood Through the Heart Aorta Superior vena cava Left pulmonary artery Right pulmonary artery Aortic semilunar valve Left pulmonary veins Right pulmonary veins Pulmonary semilunar valve Right atrium Interventricular septum Tricuspid valve Right ventricle Inferior vena cava Left atrium Bicuspid (mitral) valve Left ventricle Chordae tendinae Papillary muscles Chordae tendinae Papillary muscles Thoracic aorta (descending)

7 The Heart Electrical Conduction System Sinoatrial (SA) node Internodal pathways Bundle of His (AV bundle) Atrioventricular (AV) node Right and left bundle branches Purkinje fibres

8 Excitation of the Heart Sinoatrial node (SA node): v Specialized region of tissue found in wall of right atrium v Location where electrical signals are initiated ( pacemaker ) Atrioventricular node (AV node): v Passes electrical signal from atria into ventricles v Passes electrical signal to the bundle of His (atrioventricular bundle) Bundle of His pass electrical signal to the Purkinje fibres Purkinje fibres pass electrical signal to the myocardium The myocardium contract v Leads to contraction of the heart v Leads to the pumping of blood

9 The Electrical Activity of the Heart Measured using an electrocardiogram (ECG) v Graphical representation of electrical sequence of events occurring with each contraction of the heart v Each wave generated during contraction is named: P wave: represents depolarization through the atria QRS complex: represents depolarization of the ventricle T wave: represents repolarization of the ventricle

10 The Electrical Activity of the Heart If, for example, a cell has a resting potential of -70mV, once the membrane potential changes to -50mV, then the cell has been depolarized. Depolarization is often caused by influx of cations, e.g. Na + through Na+ channels, or Ca2+ through Ca2+ channels. On the other hand, efflux of K+ through K+ channels inhibits depolarization, as does influx of Cl (an anion) through Cl channels. If a cell has K + or Cl currents at rest, then inhibition of those currents will also result in a depolarization.

11 Coronary Vessels Anterior View Superior vena cava Branches of right pulmonary veins Right pulmonary veins Right atrium Right coronary artery Small cardiac vein Right ventricle Inferior vena cava Aorta Left pulmonary artery Branches of left pulmonary artery Pulmonary trunk Left pulmonary veins Left atrium Anterior interventricular branch of left coronary artery Great cardiac vein Left ventricle Thoracic aorta (descending)

12 Wolff-Parkinson-White syndrome Bicuspid valve A person with this syndrome may have: Chest pain or chest tightness Dizziness Light-headedness Fainting Palpitations (tachycardia) (a sensation of feeling your heart beat) Shortness of breath v=mngl6dvwu8m v=585bszuiz_q&feature=fvwrel

13 Wolff-Parkinson-White syndrome

14 Wolff-Parkinson-White syndrome

15 Cardiac Cycle Blood Pressure Cardiac cycle: series of events occurring through one heartbeat Involves two phases: v Diastole phase (relaxation) Heart fills with blood v Systole phase (contraction) Heart contracts and ejects blood

16 Unit 4 Evolution of Sport Oral Presentation Criteria: - length of presentation - 20 minutes - evidence of student preparation - audience participation/appeal - audio visual/technology - presentation of the information (logical, flowing)

17 Unit 4 Evolution of Sport

18 Lance Armstrong Ethics (If everyone is doing?, Big Business (Nike dropped)

19 Felix s Jump from Space Are we pushing our bodies to much for performance and money

20 Khalif Mitchell Suspended may fired for racial Slur on Twitter - Both of them hide money with the Ch**ks, Presidential Canidates - =

21 The Vascular System and Blood Vascular System: v A network of vessels that transport blood throughout the body; vessels divided into four main categories: Arteries: carry blood away from the heart to different organs Arterioles: regulate blood distribution to various tissues of the body Capillaries: responsible for the exchange of gases and nutrients with the tissues Veins (venules): return blood to the heart

22 Summary of the Vascular System Large veins Large arteries Medium veins Medium arteries Arteriole Capillary bed Venules Capillaries Precapillary sphincters

23 The Return of Blood from the Veins The skeletal muscle pump: v Upon contraction of skeletal muscle, blood is pushed/ massaged back to the heart The thoracic pump: v Pressure in veins (in the chest) decrease while pressure in veins (in the abdominal cavity) increase upon intake of breath v Difference in pressure pushes blood from veins in the abdominal cavity into veins in the thoracic cavity The nervous system: v Sends a signal to veins v Veins constrict allowing more blood back to the heart The skeletal muscle pump

24 The Return of Blood from the Veins Varicose Veins The skeletal muscle pump

25 The Return of Blood from the Veins Varicose Veins Leg muscles pump the veins to return blood to the heart (the calf muscle pump mechanism), against the effects of gravity. When veins become varicose, the leaflets of the valves no longer meet properly, and the valves do not work (valvular incompetence). This allows blood to flow backwards and they enlarge even more. The skeletal muscle pump

26 Properties of Blood Two main components: v Plasma Fluid component of blood (mostly water) v Blood cells Red blood cells (erythrocytes) ² Made in bone marrow ² Transport O 2 and CO 2 in the blood ² Transport nutrients and waste ² Contain hemoglobin White blood cells (leukocytes) ² Destroy foreign elements ² Critical in the function of the immune system Platelets ² Regulate blood clotting Plasma 55% 90% water 7% plasma proteins 3% other (acids, salts) Formed elements 45% >99% red blood cells <1% white blood cells and platelets

27 Properties of Blood fat after a burger, salts)

28 Cardiovascular Dynamics Cardiovascular system adapts to meet the demands that are placed on it Heart adjusts amount of blood pumped by altering: v Heart rate (HR) duration of each cardiac cycle v Stroke volume(sv) volume of blood ejected by ventricles v Cardiac output (Q) HR Î SV = Q Frank-Starling Law: v Ability of the heart to stretch and increase the force of contraction Ejection fraction v Measure of stroke volume calculated by use of a formula

29 Cardiac Cycle Blood Pressure Cardiac cycle: series of events occurring through one heartbeat Involves two phases: v Diastole phase (relaxation) Heart fills with blood v Systole phase (contraction) Heart contracts and ejects blood

30 Blood Pressure Blood Pressure is the force exerted by the blood against the walls of the arteries Measuring blood pressure: systolic pressure over diastolic pressure v Systolic blood pressure: Pressure observed in the arteries during contraction phase v Diastolic blood pressure: Pressure observed in the arteries during relaxation phase of the heart

31 Blood Pressure

32 Normal Blood Pressure Normal blood pressure (BP): 120mmHg over 80mmHg Hypertension v BP greater than 140mmHg over 90mmHg Factors affecting BP v Diet v Aerobic exercise v Stress

33 Blood Flow Distribution

34 Effects of Training

35 The Respiratory System Composed of structures that allow: v Passage of air from outside the body to the lungs v Gas exchange to occur Three main functions: v Supply O 2 to the blood v Remove CO 2 from the blood v Regulate blood ph (acid-base balance) Divided into two zones: v Conductive zone v Respiratory zone istockphoto.com/ Eraxion

36 Respiratory System Structure Nasal cavity Pharynx Larynx Mouth Epiglottis Trachea Right and left primary bronchi Secondary bronchi Tertiary bronchioles Smooth muscle Terminal bronchiole Respiratory bronchiole Pulmonary venule Alveolar sacs Pulmonary arteriole

37 The Conductive Zone The conductive zone is composed of structures that transport air to the lungs: v Mouth and nose v Larynx v Trachea v Primary and secondary bronchi v Tertiary and terminal bronchioles Filters air taken in with each breath

38 The Respiratory Zone The respiratory zone is composed of structures involved with the exchange of gases: v Respiratory bronchioles v Alveolar ducts v Alveolar sacs

39 Mechanisms of Breathing Inspiration: v Contraction of diaphragm v Thoracic cavity expands Air pressure in thoracic cavity is lower than air pressure outside the body v Air rushes in to lungs to restore balance Lung pressure = atmospheric pressure Expiration: v Alveolar sacs recoil as diaphragm relaxes v Air is expelled v Thoracic cavity reduces v Lung pressure>atmospheric pressure istockphoto.com/ ShaneKato

40 Ventilation Ventilation (V E ) is the volume of air moved by the lungs in 1 minute Influenced by two factors: v Tidal volume (V T ) Volume of air in each breath v Respiratory frequency (f) Number of breaths taken per minute

41 Respiratory Control Centres Respiratory control centres found within brain stem: v Medulla oblongata v Pons Inspiratory centre ² breaths per minute at rest Expiratory centre ² Two main functions: Ø Ensure the inspiratory muscles never completely relax Ø Stimulate forceful expiration when required (during exercise) Pneumotaxic and apneustic centres ² Ensure smooth transition of inhalation to exhalation ² Fine-tune the breathing pattern

42 Lung Volumes Lung Volumes are divided into two categories: v Static lung volumes Determined by the actual structure of the lung Three important static lung volumes: ² Total lung capacity (TLC) Ø Maximum volume of air that lungs can hold Ø Sum of vital capacity ² Vital capacity (VC) Ø Maximum amount of air that can be exhaled following a maximal inhalation ² Residual volume (RV) v Dynamic lung volumes Ø Air that remains in lungs following a maximal exhalation Dependent on volume as well as movement/flow of air

43 Fractional Concentrations and Partial Pressures of Main Gasses Found in Air

44 Fractional Concentrations and Partial Pressures of Main Gasses Mount Everest The atmospheric pressure at the top of Everest is about a third of sea level pressure, meaning there is about a third as much oxygen available to breathe as at sea level.

45 Training at High Altitude Proponents claim that when such athletes travel to competitions at lower altitudes they will still have a higher concentration of red blood cells for days, and this gives them a competitive advantage. Some athletes live permanently at high altitude, only returning to sea level to compete, but their training may suffer due to less available oxygen for workouts.

46 Gas Exchange Diffusion mediates gas exchange v Diffusion is the movement of a gas, liquid, or solid from a region of high concentration to low concentration Can only occur if a difference in concentration exists ² Concentration gradient Diffusion pathway v Area through which gases move from the lungs into the blood; from the blood into the tissue, and back v Rates of diffusion depend on: Size of concentration gradient Thickness of barrier between two areas Surface area between two areas

47 Oxygen/Carbon Dioxide Transport Oxygen (O 2 ) transport within the blood achieved in two ways: v O 2 dissolved within the plasma Represents 2% of O 2 found in the blood v Binds to hemoglobin Carbon dioxide (CO 2 ) transport achieved in three ways: v Trace amounts of CO 2 dissolved within the plasma v Binds to hemoglobin v Bicarbonate system

48 External and Internal Respiration External respiration is the result of two main factors: v Increase in pulmonary ventilation (V E ) Maintains necessary gradients in the partial pressures of both O 2 and CO 2 v Increase in blood flow to the lungs Caused by and increase in cardiac output Internal respiration involves exchange of gases at tissue level extraction of O 2 at tissues is increased Occurs as result of four main factors: v Increase in partial pressure of oxygen (PO 2 ) gradient v Increase in partial pressure of carbon dioxide (PCO 2 ) v Decrease in ph v Increase in temperature

49 Flow of External and Internal Respiration

50 a-vo2 Difference

51 Lactate Threshold

52 Oxygen Deficit and EPOC

53 Physiological Adaptations Due to Endurance Training

54 Asthma istockphoto.com/ TommL Asthma (acute or chronic) is characterized by: v Spasm of smooth muscle lining the respiratory system v Oversecretion of mucous v Swelling of cells lining the respiratory tract Asthma results in: v Dyspnea (shortness of breath) v Wheezing during breathing Factors that stimulate attacks: v Exercise v Allergic reactions/contaminates v Stress Controlled through the use of medications

55 Chronic Obstructive Pulmonary Disease Chronic obstructive pulmonary disease (COPD): v Describes a family of diseases that lead to a reduction in airflow through the respiratory system v Often fatal in severe cases v Persistent conditions cannot be relieved (quickly or effectively) through the use of medications v Individuals experience dyspnea while performing everyday activities v Treatment includes: Medication Oxygen therapy Respiratory muscle training

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