exercise science section 7: the cardiovascular and … · 2013-09-04 · this material may be used...

©Thompson Educational Publishing, Inc. 2003. All material is copyright protected. It is illegal to copy any of this material. This material may be used only in a course of study in which Exercise Science: An Introduction to Health and Physical Education (Temertzoglou/Challen) is the required textbook.

An Introduction to Health and Physical Education

Ted Temertzoglou Paul Challen ISBN 1-55077-132-9

Exercise Science Section 7: The Cardiovascular and Respiratory

Systems


The Cardiovascular System

t  Composed of: v  Heart v  Blood vessels v  Blood

t  Functions: v  Delivery of O2, fuel, and

nutrients to the tissues of the body

v  Removal of CO2 and waste products from the tissues

v  Maintenance of a constant body temperature (thermoregulation)

v  Prevention of infection (immune function)


The Heart

t  Formed from myocardium, a specialized muscle tissue t  Surrounded by pericardium (tough protective sac); allows heart to

expand and contract t  Epicardium lines outside of heart; endocardium lines inside of heart t  Made up of four separate chambers: atria (upper chambers) and

ventricles (lower chambers) t  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)


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 Left ventricle

Pulmonary artery Pulmonary vein

Tricuspid valve Bicuspid (mitral) valve

Pulmonary valve Aortic valve


The Internal Anatomy of the Heart

Aorta

Superior vena cava

Right pulmonary artery Aortic semilunar valve

Right pulmonary veins

Right atrium

Pulmonary semilunar valve

Tricuspid valve

Right ventricle

Inferior vena cava

Left pulmonary artery

Left pulmonary veins

Left atrium

Bicuspid (mitral) valve

Left ventricle

Chordae tendinae

Papillary muscles


Chordae tendinae

Papillary muscles

Thoracic aorta (descending)


Path of Blood Through the Heart

Aorta

Superior vena cava

Right pulmonary artery Aortic semilunar valve


Right atrium

Pulmonary semilunar valve

Tricuspid valve

Right ventricle

Inferior vena cava

Left pulmonary artery


Left atrium

Bicuspid (mitral) valve

Left ventricle

Chordae tendinae

Papillary muscles


Chordae tendinae

Papillary muscles



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


Excitation of the Heart

t  Sinoatrial node (SA node): v  Specialized region of tissue found in wall of

right atrium v  Location where electrical signals are initiated

(“pacemaker”) t  Atrioventricular node (AV node):

v  Passes electrical signal from atria into ventricles

v  Passes electrical signal to the bundle of His (atrioventricular bundle)

t  Bundle of His pass electrical signal to the Purkinje fibres

t  Purkinje fibres pass electrical signal to the myocardium

t  The myocardium contract v  Leads to contraction of the heart v  Leads to the pumping of blood


The Electrical Activity of the Heart

t  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


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.


Coronary Vessels – Anterior View

Superior vena cava

Branches of 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 atrium Anterior interventricular branch of left coronary artery

Great cardiac vein

Left ventricle



Wolff-Parkinson-White syndrome – Bicuspid valve

t  A person with this syndrome may have: t  Chest pain or chest tightness t  Dizziness t  Light-headedness t  Fainting t  Palpitations (tachycardia) (a sensation of feeling

your heart beat) t  Shortness of breath t  http://www.youtube.com/watch?

v=MNgl6DVwU8M t  http://www.youtube.com/watch?

v=585BSzuIZ_Q&feature=fvwrel t  http://www.youtube.com/watch?v=1fi-iz0NHW8


Wolff-Parkinson-White syndrome


Cardiac Cycle – Blood Pressure

t  Cardiac cycle: series of events occurring through one heartbeat t  Involves two phases:

v  Systole phase (contraction)   Heart contracts and ejects blood

v  Diastole phase (relaxation)   Heart fills with blood


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)


Unit 4 Evolution of Sport


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


Felix’s Jump from Space – Are we pushing our bodies to much for

performance and money


Khalif Mitchell Suspended may fired for racial Slur on Twitter - “Both of them hide

money with the Ch**ks,” Presidential Canidates - =


The Vascular System and Blood

t  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


Summary of the Vascular System

Large veins

Medium veins

Venules

Large arteries

Medium arteries

Capillaries

Arteriole

Precapillary sphincters

Capillary bed


The Return of Blood from the Veins

t  The skeletal muscle pump: v  Upon contraction of skeletal muscle,

blood is pushed/ massaged back to the heart

t  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

t  The nervous system: v  Sends a signal to veins v  Veins constrict allowing more blood

back to the heart

The skeletal muscle pump


The Return of Blood from the Veins – Varicose Veins



The Return of Blood from the Veins – Varicose Veins t  Leg muscles pump the veins

to return blood to the heart (the calf muscle pump mechanism), against the effects of gravity.

t  When veins become varicose, the leaflets of the valves no longer meet properly, and the valves do not work (valvular incompetence).

t  This allows blood to flow backwards and they enlarge even more.



Properties of Blood t  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 O2 and CO2 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


Properties of Blood – fat after a burger

, salts)


Cardiovascular Dynamics

t  Cardiovascular system adapts to meet the demands that are placed on it

t  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 t  Frank-Starling Law:

v  Ability of the heart to stretch and increase the force of contraction t  Ejection fraction

v  Measure of stroke volume calculated by use of a formula


Cardiac Cycle – Blood Pressure

t  Cardiac cycle: series of events occurring through one heartbeat t  Involves two phases:

v  Systole phase (contraction)   Heart contracts and ejects blood

v  Diastole phase (relaxation)   Heart fills with blood


Blood Pressure

t  Blood Pressure is the force exerted by the blood against the walls of the arteries

t  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


Blood Pressure


Normal Blood Pressure

t  Normal blood pressure (BP): 120mmHg over 80mmHg t  Hypertension

v  BP greater than 140mmHg over 90mmHg

t  Factors affecting BP v  Diet v  Aerobic exercise v  Stress


Blood Flow Distribution


Effects of Training


The Respiratory System

t  Composed of structures that allow: v  Passage of air from outside

the body to the lungs v  Gas exchange to occur

t  Three main functions: v  Supply O2 to the blood v  Remove CO2 from the blood v  Regulate blood pH (acid-base

balance) t  Divided into two zones:

v  Conductive zone v  Respiratory zone

© iS

tockphoto.com/”E

raxion”


Respiratory System Structure

Nasal cavity

Mouth Epiglottis

Pharynx

Larynx

Right and left primary bronchi

Trachea

Secondary bronchi

Tertiary bronchioles

Smooth muscle

Pulmonary arteriole

Pulmonary venule

Terminal bronchiole

Respiratory bronchiole

Alveolar sacs


The Conductive Zone

t  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 t  Filters air taken in with each

breath


The Respiratory Zone

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


Mechanisms of Breathing t  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 t  Expiration:

v  Alveolar sacs recoil as diaphragm relaxes

v  Air is expelled v  Thoracic cavity reduces v  Lung pressure>atmospheric

pressure

© iStockphoto.com/”ShaneKato”


Ventilation

t  Ventilation (VE) is the volume of air moved by the lungs in 1 minute

t  Influenced by two factors: v  Tidal volume (VT)

 Volume of air in each breath v  Respiratory frequency (f)

 Number of breaths taken per minute


Respiratory Control Centres

t  Respiratory control centres found within brain stem: v  Medulla oblongata

 Inspiratory centre ² 15-20 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) v  Pons

 Pneumotaxic and apneustic centres ² Ensure smooth transition of inhalation to exhalation ² Fine-tune the breathing pattern


Lung Volumes t  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)

Ø Air that remains in lungs following a maximal exhalation

v  Dynamic lung volumes  Dependent on volume as well as movement/flow of air


Fractional Concentrations and Partial Pressures of Main Gasses Found in Air


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.


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 10–14 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.


Gas Exchange

t  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

t  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


Oxygen/Carbon Dioxide Transport

t  Oxygen (O2) transport within the blood achieved in two ways: v  O2 dissolved within the plasma

 Represents 2% of O2 found in the blood v  Binds to hemoglobin

t  Carbon dioxide (CO2) transport achieved in three ways: v  Trace amounts of CO2 dissolved within the plasma v  Binds to hemoglobin v  Bicarbonate system


External and Internal Respiration

t  External respiration is the result of two main factors: v  Increase in pulmonary ventilation (VE)

 Maintains necessary gradients in the partial pressures of both O2 and CO2

v  Increase in blood flow to the lungs  Caused by and increase in cardiac output

t  Internal respiration involves exchange of gases at tissue level – extraction of O2 at tissues is increased

t  Occurs as result of four main factors: v  Increase in partial pressure of oxygen (PO2) gradient v  Increase in partial pressure of carbon dioxide (PCO2) v  Decrease in pH v  Increase in temperature


Flow of External and Internal Respiration


a-vO2 Difference


Lactate Threshold


Oxygen Deficit and EPOC


Physiological Adaptations Due to Endurance Training


Asthma t  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 t  Asthma results in:

v  Dyspnea (shortness of breath) v  Wheezing during breathing

t  Factors that stimulate attacks: v  Exercise v  Allergic reactions/contaminates v  Stress

t  Controlled through the use of medications

© iStockphoto.com/”TommL”


Chronic Obstructive Pulmonary Disease

t  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

exercise science section 7: the cardiovascular and … · 2013-09-04 · this material may be used...

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