IB Sports exercise and health science Exercise physiology

IB Sports, exercise and health science Exercise physiology 2. 1. 1 List the principal structures of the ventilatory system Topic 2 Exercise Physiology Sub-topics 1. Structure & function of the ventilatory system 2. Structure & function of the cardiovascular system § The principle structures of the respiratory system are: § § § § Nose/Mouth Pharynx Larynx: voice box Trachea Bronchioles Lungs Alveoli

IB Sports, exercise and health science Topic 2 Exercise Physiology Exercise physiology 2. 1. 1 List the principal structures of the ventilatory system Sub-topics 1. Structure & function of the ventilatory system 2. Structure & function of the cardiovascular system http: //www. umm. edu/respiratory/images/respiratory_anatomy. jpg

IB Sports, exercise and health science Exercise physiology 2. 1. 1 List the principal structures of the ventilatory system Topic 2 Exercise Physiology Sub-topics 1. Structure & function of the ventilatory system 2. Structure & function of the cardiovascular system § § Smooth muscle tissue is found on the walls of some of our internal hollow organs It produces smooth, rhythmical actions. We can not consciously control the action of smooth muscle. It is subsequently termed involuntary. e. g. movement of blood and air in the lungs DET PDHPE Distance Education Programme

IB Sports, exercise and health science Exercise physiology 2. 1. 1 List the principal structures of the ventilatory system Topic 2 Exercise Physiology Sub-topics § 1. Structure & function of the ventilatory system 2. Structure & function of the cardiovascular system § The trachea is a thin walled tube about the diameter of an average garden hose. It is composed of very thin, tough connective tissue and is strengthened at intervals by incomplete rings of cartilage. The trachea muscle runs down the posterior wall of the trachea. This is an example of smooth muscle. Solomon & Davis

IB Sports, exercise and health science Topic 2 Exercise Physiology Exercise physiology 2. 1. 2 Outline the functions of the conducting airways Sub-topics § 1. Structure & function of the ventilatory system 2. Structure & function of the cardiovascular system § § The nostrils are fringed with coarse hair, which strains large particles out of the airstream and may also serve to protect the nasal cavity from invasion by insects. The interior of the nasal cavity contains projections of considerable surface area. These projections, nasal conchae, make the airstream turbulent and subsequently warm and hydrate it. Thanks to the structure of the nose, air entering the trachea is virtually 100% humidified. Solomon & Davis

IB Sports, exercise and health science Topic 2 Exercise Physiology Exercise physiology 2. 1. 2 Outline the functions of the conducting airways Sub-topics 1. Structure & function of the ventilatory system 2. Structure & function of the cardiovascular system www. nlm. nih. gov

IB Sports, exercise and health science Topic 2 Exercise Physiology Sub-topics 1. Structure & function of the ventilatory system 2. Structure & function of the cardiovascular system Exercise physiology 2. 1. 2 Outline the functions of the conducting airways § § § Air passes through the 3 portions of the pharynx, which provides a low resistance path for airflow, to the trachea via the larynx. In addition to it’s function as the voice box the larynx protects the trachea from invasion by foods and fluids. The cartilaginous trachea, branches into the two main bronchi. § The lining of the tracheobronchial system is designed to protect the lungs from dehydration and invasion by foreign particles, including micro-organisms. Solomon & Davis

IB Sports, exercise and health science Topic 2 Exercise Physiology Exercise physiology 2. 1. 2 Outline the functions of the conducting airways Sub-topics § 1. Structure & function of the ventilatory system 2. Structure & function of the cardiovascular system § The lungs themselves develop at the end of the bronchi. They are elastic spongy organs. Gas exchange is carried out by a complex of structures at the end of each terminal bronchioles. They are simple thin walled structures which also have numerous thin-walled outpocketings called alveoli, which are specialised for the function of gaseous exchange. Solomon & Davis

IB Sports, exercise and health science Topic 2 Exercise Physiology Exercise physiology 2. 1. 3 Define respiratory terms Sub-topics 1. Structure & function of the ventilatory system 2. Structure & function of the cardiovascular system § Pulmonary ventilation: is commonly referred to as breathing. It is the process of air flowing into the lungs during inspiration (inhalation) and out of the lungs during expiration (exhalation). Air flows because of pressure differences between the atmosphere and gases inside the lungs. § DET PDHPE Distance Education Programme

IB Sports, exercise and health science Topic 2 Exercise Physiology Sub-topics 1. Structure & function of the ventilatory system 2. Structure & function of the cardiovascular system Exercise physiology 2. 1. 3 Define respiratory terms § Air, like other gases, flows from a region with higher pressure to a region with lower pressure. Muscular breathing movements and recoil of elastic tissues create the changes in pressure that result in ventilation. Pulmonary ventilation involves three different pressures: • Atmospheric pressure • Intraalveolar (intrapulmonary) pressure • Intrapleural pressure Atmospheric pressure is the pressure of the air outside the body. Intraalveolar pressure is the pressure inside the alveoli of the lungs. Intrapleural pressure is the pressure within the pleural cavity. These three pressures are responsible for pulmonary ventilation. http: //training. seer. cancer. gov/module_anatomy/unit 9_2_resp_vent_mechanics. html

IB Sports, exercise and health science Topic 2 Exercise Physiology Exercise physiology 2. 1. 3 Define respiratory terms It is important to understand the various volumes and capacities of the lungs in order to appreciate the effects of exercise on the respiratory system. Sub-topics 1. Structure & function of the ventilatory system 2. Structure & function of the cardiovascular system § § § Total lung capacity can be calculated by adding vital capacity to residual volume of the lungs. During normal, quiet respiration, about 500 m. L of air is inspired. The same amount of air moves out with expiration. This volume of air is called the tidal volume. When we forcibly take a deep breath, we can take in up to 3100 m. L above the tidal volume. This additional air is the inspiratory reserve volume. § Browne et. al 2001

IB Sports, exercise and health science Topic 2 Exercise Physiology Exercise physiology 2. 1. 3 Define respiratory terms Sub-topics § 1. Structure & function of the ventilatory system 2. Structure & function of the cardiovascular system § We can also forcibly exhale. This is termed the expiratory reserve volume. Even after the expiratory reserve volume is expelled, some air is still trapped in the lungs because of pressure. This is called the residual volume. § DET PDHPE Distance Education Programme Browne et al 2001

IB Sports, exercise and health science Topic 2 Exercise Physiology Exercise physiology 2. 1. 4 Explain the mechanics of ventilation in the human lungs Sub-topics 1. Structure & function of the ventilatory system 2. Structure & function of the cardiovascular system To understand how a person breathes, you need to know that a substance called pleural fluid lies between the lungs and the chest wall. Have you ever put two pieces of wet glass together (e. g. microscope slides) and found that you could not easily pull them apart. This phenomenon results from a combination of forces – surface tension, molecular cohesion and atmospheric pressure. Solomon & Davis

IB Sports, exercise and health science Topic 2 Exercise Physiology Sub-topics 1. Structure & function of the ventilatory system 2. Structure & function of the cardiovascular system Exercise physiology 2. 1. 4 Explain the mechanics of ventilation in the human lungs Think of the walls of the chest and the lungs as the two wet slides and the pleural fluid as the film of water. When the chest expands during breathing, the film of pleural fluid causes the membranous walls of the lungs to be pulled outward along with the chest walls. This means the space within the lungs increases. The air molecules in the lungs now move momentarily farther apart, so that the pressure in of the air in the lungs falls below the pressure of the atmosphere outside the body. Consequently, air from outside rushes down the trachea and into the lungs until the two pressures are equal again. This is the process of inspiration. Solomon & Davis

IB Sports, exercise and health science Topic 2 Exercise Physiology Sub-topics 1. Structure & function of the ventilatory system 2. Structure & function of the cardiovascular system Exercise physiology 2. 1. 4 Explain the mechanics of ventilation in the human lungs Observation of the skeleton reveals that each rib pivots about a vertebral joint. If it is lifted upward it also swings outward, with the thoracic cavity being enlarged anteriorly and superiorly. This is the task in quiet breathing of the external intercostal muscles. At the same time the ribs are lifted, the diaphragm (the muscular floor of the thoracic cavity) contracts downward enlarging the thoracic cavity inferiorly. This process enlarges the cavity twofold. Solomon & Davis

IB Sports, exercise and health science Topic 2 Exercise Physiology Exercise physiology 2. 1. 4 Explain the mechanics of ventilation in the human lungs Sub-topics 1. Structure & function of the ventilatory system 2. Structure & function of the cardiovascular system Expiration is almost entirely a passive process that depends on the elasticity of the lungs and chest structures, as well as fluid film surface tensions within the lungs. When inspiratory muscles are relaxed, air simply leaves the lung, much as it would leave an untied balloon. Solomon & Davis

IB Sports, exercise and health science Exercise physiology 2. 1. 4 Explain the mechanics of ventilation in the human lungs Topic 2 Exercise Physiology Sub-topics § 1. Structure & function of the ventilatory system 2. Structure & function of the cardiovascular system § This above description is for quiet breathing. When one speaks or runs, the abdominal muscles press upon the abdominal contents, squeezing them upwards against the diaphragm. The internal intercostal muscles oppose the external intercostals and pull the ribcage downward, helping to decrease thoracic cavity volume and forcibly empty the lungs. The diaphragm may also function in forcible expiration. In laboured inspiration (e. g. accompanying exercise) many of the muscles of the upper trunk are also recruited. They are only indirectly attached to the ribs and are inefficient as respiratory muscles. E. g. Pectoralis major and minor, Trapezius, Rhomboideus. Solomon & Davis

IB Sports, exercise and health science Topic 2 Exercise Physiology Exercise physiology 2. 1. 4 Explain the mechanics of ventilation in the human lungs Sub-topics 1. Structure & function of the ventilatory system 2. Structure & function of the cardiovascular system http: //www. lib. mcg. edu/eshuphysio/program/section 4/4 ch 1 img/page 17. jpg

IB Sports, exercise and health science Exercise physiology 2. 1. 5 Describe the significance of carbon dioxide in the control of pulmonary ventilation Topic 2 Exercise Physiology Sub-topics 1. Structure & function of the ventilatory system 2. Structure & function of the cardiovascular system § The entire respiratory system would be useless unless the alveolar air were regularly changed. Since humans do not possess a one-way system for air circulation through the lungs, inhaled an exhaled air must be mixed to some degree. This does not normally produce any difficulty, since the respiratory system possesses a two to threefold margin of safety and is ordinarily far more effective than it needs to be in regard to oxygen absorption. § Solomon & Davis

IB Sports, exercise and health science Exercise physiology Topic 2 Exercise Physiology 2. 1. 5 Describe the significance of carbon dioxide in the control of pulmonary ventilation Sub-topics § 1. Structure & function of the ventilatory system 2. Structure & function of the cardiovascular system § This is less true, however for carbon dioxide removal, which is an equally important task of the respiratory system. Fortunately, carbon dioxide diffuses through the alveolar walls far more readily than oxygen, but dissolved carbonic acid does not readily breakdown to form carbon dioxide. Were it not for the enzyme carbonic anhydrase, which speeds the dissociation of carbonic acid as well as it’s formation, the elimination of this gas would be hopelessly inadequate. As it is, carbon dioxide excretion is far more easily hindered than is oxygen absorption. Thus breathing is governed not by oxygen, but the carbon dioxide content of the blood. § Solomon & Davis

IB Sports, exercise and health science Exercise physiology 2. 1. 5 Describe the significance of carbon dioxide in the control of pulmonary ventilation Topic 2 Exercise Physiology Sub-topics 1. Structure & function of the ventilatory system 2. Structure & function of the cardiovascular system § Whilst respiration appears at first a voluntary activity, if that were true it would not continue when were asleep or inattentive. It is subject to great conscious influence, but despite the fact it is carried out by such voluntary muscles as the intercostals and the diaphragm, breathing is basically an automatic and involuntary activity. § Solomon & Davis

IB Sports, exercise and health science Topic 2 Exercise Physiology Exercise physiology 2. 1. 6 Outline the role of hemoglobin in oxygen transportation Sub-topics 1. Structure & function of the ventilatory system 2. Structure & function of the cardiovascular system http: //www. nlm. nih. gov/medlineplus/ency/images/ency/fullsize/19510. jpg

IB Sports, exercise and health science Topic 2 Exercise Physiology Sub-topics 1. Structure & function of the ventilatory system 2. Structure & function of the cardiovascular system Exercise physiology 2. 1. 6 Outline the role of hemoglobin in oxygen transportation Hemoglobin is the iron containing oxygen transport protein in the red blood cells. It transports oxygen from the lungs to the rest of the body, such as the muscles, where it releases it’s load of oxygen. The name hemoglobin is the concatenation of heme and globin, reflecting the fact that each subunit of hemoglobin is a globular protein with an embedded heme (or haem) group; each heme group contains an iron atom, and this is responsible for the binding of oxygen. In humans, each heme group is able to bind one oxygen molecule with one hemoglobin molecule can therefore bind four oxygen molecules. http: //en. wikipedia. org/wiki/Hemoglobin

IB Sports, exercise and health science Exercise physiology 2. 1. 7 Explain the process of gaseous exchange at the alveoli Topic 2 Exercise Physiology Sub-topics § 1. Structure & function of the ventilatory system 2. Structure & function of the cardiovascular system § Gas exchanges between the air in the alveoli and the blood capillaries occur across the respiratory membrane in a process known as pulmonary diffusion. The most critical factor for gas exchange between alveoli and the blood is the pressure gradient between the gases in the two areas. According to Dalton’s law of partial pressures, the pressure of a mixture of gases equals the sum of the individual pressures (partial pressures) of each gas in the mixture. Browne et. al

IB Sports, exercise and health science Exercise physiology 2. 1. 7 Explain the process of gaseous exchange at the alveoli Topic 2 Exercise Physiology Sub-topics § 1. Structure & function of the ventilatory system 2. Structure & function of the cardiovascular system § If we take a normal breath of air, which contains nitrogen, oxygen and carbon dioxide, the total pressure of the air is equal to the sum of the partial pressures of the individual gases in the blood and the alveoli create a pressure gradient, so one into the other (from high partial pressure to low partial pressure) The partial pressure of oxygen arriving at the alveoli is high, and the partial pressure of it in the capillaries is low. Therefore oxygen diffuses from the alveoli into the blood. The opposite is true for carbon dioxide. Browne et. al

IB Sports, exercise and health science Topic 2 Exercise Physiology Sub-topics 1. Structure & function of the ventilatory system 2. Structure & function of the cardiovascular system Exercise physiology 2. 1. 7 Explain the process of gaseous exchange at the alveoli

Be prepared for discussions • Affect of exercise on hemoglobin at altitude • What are some of the effects/results of breathing air at altitude? Below sea level? • What is theory behind hyperventilation for improved breath holding ability?