Forum Fisiologi Senam.pptx

QSU3043

EXERCISE PHYSIOLOGY

ONLINE FORUM: TITLE: VENTILATION DURING EXERCISE

Name

Matric No

ERWAN SHA BIN HABINULLAH

D20152072240

EXAMINER’S SECTION QSU3043: EXERCISE PHYSIOLOGY ONLINE FORUM EVALUATION FORM (5 marks)

Group A

During exercise, the increase in ventilationoccurs to meet the increasing oxygen demands. Explain how ventilation is being regulated during exercise. State in your answer explanation regarding control of ventilation (chemical and non-chemical), minute ventilation and lung volumes. During exercise, the increase in ventilation which occurs to meet the increasing oxygen demands (called “hyperpnea”) is not fully explained by the control of the peripheral or central chemoreceptors alone. There are non-chemical controls of ventilation that are required to provide input to the respiratory centre to increase ventilation, especially during the initiation of exercise when ventilation needs to increase quickly. Though the process of respiration is quite complex, in basic terms, it is process of exchanging carbon dioxide for oxygen. The respiration rate is the number of breaths taken per minute. The way the respiratory system responds to exercise will vary from person to person, and also by the activity being performed. Other factors, including cardiovascular fitness, current health status, age and even gender, affect respiration rate both at rest and during exercise. These “non-chemical controls” of ventilation include: 1.the motor cortex (cortical control): feed-forward mechanism to increase ventilation at the onset of exercise. 2. active muscles and joint receptors: active muscles and joints provide feedback to the respiratory centre to increase ventilation (muscle metaboreflex) in order to meet the higher oxygen demands and to remove carbon dioxide 3. core body temperature: higher body temperature stimulates increased ventilation 4. stretch receptors in the lungs tissue and bronchioles: when these receptors are stretched, they send a signal to the medulla to stop inhalation and start exhalation. This ensures that the lungs will never exceed their maximal physical capacity. MINUTE VENTILATION AT REST At rest, the diaphragm and the intercostal muscles (muscles between the ribs) contract and expand with each breath. Every breath expands and contracts the thoracic cavity, which is the space between the ribs and the spinal column. During inhalation, the volume of the thoracic cavity increases as air flows into the lungs. When the air is expelled, the volume decreases as air is forced out of the lungs. With every breath, air is moved into the lungs and oxygen and carbon dioxide are exchanged. Oxygen gets carried away on the red blood cells, and carbon dioxide is expelled into the air. The exchange of these two gases takes place without much fanfare when the body is at rest. When the need for oxygen increases during exercise however, the rate of respiration can change dramatically. Minute Ventilation is determined by the following equation:

DURING EXERCISE As exercise intensifies and the body’s need for fresh oxygen increases, the ventilation rate responds accordingly. The metabolic byproducts of exercise build up as a result of cellular respiration, and the amount of carbon dioxide (CO2) in the system also increases to act as a buffer against these acidic byproducts. As the concentration of CO2 increases, the body responds by breathing deeper, and more frequently to dispel the CO2. Working muscles also require fresh oxygen. The rate of respiration also increases to facilitate the delivery of oxygen to the blood stream, where it is then transported to the working muscles. Ventilatory Capacity Oxygen is transported to your muscles and carbon dioxide is transported away from your muscles by your blood. The actual exchange of these gases with the air you breathe occurs in your lungs. Blood is circulated through your lungs by your cardiovascular system. Generally speaking, in most people, the capacity of your lungs far exceeds the capacity of your cardiovascular system. For example, as explained by Illinois State University’s Dale Brown in “Exercise and Sport Science,” a four- to five-fold increase in breathing rate and a five- to seven-fold increase in tidal volume during exercise compared to rest provide the potential to elevate minute ventilation to 20 to 30 times the resting value. This far exceeds the increase in the amount of blood you can circulate through your lungs during exercise, which is typically only five to seven times the resting value. This means that your cardiovascular system is the limiting factor and there will be no overload on your lungs that forces them to increase their capacity over time due to regular aerobic exercise..