sports science - topic 2

2.1.1: List the principal structures of the ventilatory system

Nose, mouth, pharynx, larynx, trachea, bronchi, bronchioles, lungs and alveoli

2.1.2: Outline the functions of the conducting pathways

1. To provide a low resistance pathway for airflow

2. Defence against chemicals and other harmful substances

3. To warm and moisten air

2.1.3: Pulmonary ventilation

Inflow and outflow of air between the atmosphere and the lungs (breathing)

2.1.3: Tidal Volume

Volume of air inspired or expired per breath

• Tidal volume increases during exercises

2.1.3: Inspiratory Reserve Volume

Additional inspired air over and above tidal volume (VT)

2.1.3: Relationship between Inspiratory Reserve Volume and Tidal Volume

when VT (Tidal volume) increases, IRV (Inspiratory reserve volume) decreases by the same volume and vice versa.

• e.g. IRV decreases during exercise while VT increases

2.1.3: Expiratory Reserve Volume

Volume of air in excess of tidal volume that can be exhaled forcibly

2.1.3: Total Lung Capacity

Volume of air in the lungs after a maximum inhalation and includes the residual volume (average adult = 4-8 litres)

2.1.3: Vital Capacity

The maximal volume of air that can forcefully be expired following a maximal inspiration - the functional capacity of the lungs

2.1.3: Residual Volume

Volume of air still contained in the lungs AFTER a maximal inhalation

2.1.3: What happens to VT during exercise?

VT increases

2.1.3: Diagram of total lung volume

2.1.3: What does the red arrow represent?

Tidal volume

2.1.3: What does the blue arrow represent?

Inspiratory reserve volume

2.1.3: What does the green arrow represent?

Expiratory reserve volume

2.1.3: What does the yellow arrow represent?

Vital capacity

2.1.3: What does the purple/black arrow represent?

Total lung capacity

2.1.3: What does the orange arrow represent?

Residual volume

2.1.4: Explain the mechanics of ventilation in the human lung - Inhalation

• Volume of thorax: increases

• Diaphragm muscle: contracts

• Diaphragm: flattens and pushes down digestive organs

• External intercostal muscles: contracts/expands

• Rib cage: moves upward and outward

• Pressure in chest cavity: decreases below atmospheric pressure

• Movement of air: into the lungs down the pressure gradient

2.1.4: What happens to diaphragm during inhalation?

Flattens and pushes down digestive organs

2.1.4: What happens to external intercostal muscles during inhalation?

Contract/expand

2.1.4: What happens to the volume of the thorax during inhalation?

Increases

2.1.4: What happens to pressure in chest cavity during inhalation?

Decreases (because lungs open up (volume increases) molecules inside the lungs have more space to move around)

2.1.4: Explain the mechanics of ventilation in the human lung - Exhalation

• Volume of thorax: decreases

• Diaphragm muscle: contracts

• Diaphragm: relaxes and resumes to dome shape

• External intercostal muscles: relaxes

• Rib cage: inward and downward

• Pressure in chest cavity: increases below atmospheric pressure

• Movement of air: air forced out of lungs

2.1.4: Explain the mechanics of inhalation for a swimmer

As the head is lifted from the water:

• external intercostal contract

• rib cage moves upwards and outwards

• diaphragm flattens/contracts

• thoracic cavity volume increases in size/capacity

• thoracic cavity pressure decreases

2.1.5: Describe the nervous and chemical control of ventilation during exercise

During exercise, ventilation is controlled both nervously and chemically to meet the increased oxygen demands and manage carbon dioxide levels. This involves chemoreceptors, the respiratory centre and neural inputs.

2.1.5: Describe the nervous and chemical control of ventilation during exercise - Chemoreceptors

Detect changes in CO2 and pH, signalling the respiratory centre.

2.1.5: Describe the nervous and chemical control of ventilation during exercise - Respiratory centre

Located in the medulla oblongata, controls the rate and depth of breathing

2.1.5: Describe the nervous and chemical control of ventilation during exercise - Neural inputs

Includes lung stretch receptors, muscle proprioceptors and signals from higher brain centres which respond to physical activity during exercise, ensuring that ventilation increases to meet the body’s demand during exercise.

2.1.6: Outline the role of haemoglobin in oxygen transportation. 

Haemoglobin is the main oxygen transport protein in red blood cells (erythrocytes), binding 98.5% of blood oxygen. It transports oxygen from the lungs to the working tissues, where it is needed for energy production. Haemoglobin releases oxygen to tissues, with more oxygen released during strenuous exercise compared to rest.

• haemoglobin has a high affinity for oxygen, allowing it to effectively pick up oxygen in the lungs.

• also transports carbon dioxide from the tissues back to the lungs for expiration.

• each haemoglobin molecule can carry four oxygen molecules, binding reversibly to form oxyhemoglobin.

• higher levels of haemoglobin are found in trained athletes, enhancing their oxygen transport capacity.

2.1.7: Explain the process of gaseous exchange at the alveoli

• Gaseous exchange occurs through diffusion across the respiratory membrane, which separates the alveoli from the surrounding capillary network

• O2 DIFFUSES/PASSES from the lungs inot the capillaries (blood)

• CO2 DIFUSSES/PASSES from the capillaries (blood) into the lungs

• this process occurs due to differences in partial pressures which create a pressure gradient and can affect the rate of exchange

• during EXERCISE; diffusion capacity for oxygen increases and the pressure gradient for CO2 is smaler than for O2 exchange

• Partial pressure (PO2) oxygen in the alveoli is higher than in the capillaries

• Partial pressure (PCO2) of CO2 is higher in the capillaries (blood) than in the alveoli

2.2.1: State the composition of blood

Blood is composed of erythrocytes (red blood cells), leucocytes (white blood cells), thrombocytes (platelets) and plasma and transports nutrients, oxygen, carbon dioxid, hormones, antibodies, urea (heat - thermoregulation)

• 90% water

• 8% blood protetins

• 1% electrolytes

• 0.5% food substances

• 0.04% waste products

2.2.2.: Distinguish between the function of erythrocytes, leukocytes and platelets - Erythrocytes

Erythrocytes (red blood cells) contain haemoglobin and transports both oxygen and carbon dioxide (approx. 10%).

• make up 45% of blood volume

2.2.2.: Distinguish between the function of erythrocytes, leukocytes and platelets - what percentage of blood volume are erythrocytes?

45% of blood volume

2.2.2.: Distinguish between the function of erythrocytes, leukocytes and platelets - Leucocytes

Leucocytes (white blood cells) are involved in immune function, combatting infection, protecting the body from viruses and infections, by engulfing pathogens and making antibodies.

• Lymphocytes and phagocytes

• make up 3% of blood volume

2.2.2.: Distinguish between the function of erythrocytes, leukocytes and platelets - what percentage of blood volume are leucocytes?

3% of blood volume

2.2.2.: Distinguish between the function of erythrocytes, leukocytes and platelets - Thrombocytes

Thrombocytes (platelets) are cell fragments which assist in the repair process following injury by allowing blood to clot (produces scabs)

• 1% of blood volume

2.2.2.: Distinguish between the function of erythrocytes, leukocytes and platelets - what percentage of blood volume are thrombocytes?

1% of blood volume

2.2.2.: Distinguish between the function of erythrocytes, leukocytes and platelets - Plasma

Plasma is the fluid component of blood that assists in transport of substances such as food/waste products/hormones/antibodies/electrolytes

• 51% of blood volume

2.2.2.: Distinguish between the function of erythrocytes, leukocytes and platelets - what percentage of blood volume is plasma?

51% of blood volume

2.2.3: Describe the anatomy of the heart with reference to the heart chambers, valves, and major blood vessels - 4 chambers

Upper chambers: left and right atrium

Lower chambers: left and right ventricle

What are these 4 labels?

The 4 chambers of the heart

What label corresponds to number 1?

Right atrium

What label corresponds to number 2?

Right ventricle

What label corresponds to number 3?

Left atrium

What label corresponds to number 4?

Left ventricle

2.2.3: Describe the anatomy of the heart with reference to the heart chambers, valves, and major blood vessels - 4 valves

Bicuspid (mitral), tricuspid, aortic and pulmonary valve

The names of the four chambers, four valves (bicuspid, tricuspid, aortic and pulmonary valve) and the four major blood vessels (vena cava, pulmonary vein, the aorta and pulmonary artery) of the pulmonary and systemic circulation are required. The heart has its own blood supply via the coronary arteries, however the names of the coronary arteries are not required.