Breathing and Exchange of Gases Test -2

Trachea divides at the level of 5th thoracic vertebra into a right and left primary bronchi.

Vital capacity includes ERV, TV and IRV or the maximum volume of air a person can breathe out after a forced inspiration.

There are no special respiratory organs in Hirudinaria. In addition to its primary role of a protective covering, the skin also serves a respiratory function. It is provided with a rich supply of haemocoelomic fluid in an extensive system of capillaries and capillary loops, which penetrate into the spaces between the inner ends of the epidermal cells.

The epiglottis is a leaf-shaped flap of cartilage located behind the tongue, at the top of the larynx, or voice box. The main function of the epiglottis is to seal off the windpipe during eating, so that food is not accidentally inhaled.

Tidal volume (TV) = volume moved in one breath. Normal = 500 ml

• About 70% of TV reaches alveoli (350 ml) Only this amount is involved in gas exchange
• 30% in airways =respiratory passage (anatomical dead space)

So ratio = 350:150= 7:3

The toxicity in animals is caused by the extraordinary affinity of carbon monoxide for haemoglobin which is responsible for the oxygen transport (approx. 250 times greater affinity of carbon monoxide compared to oxygen.because of higher affinity it destroys the haemoglobin.

haemopneumothorax, is a medical term describing the combination of two conditions: pneumothorax, or air in the chest cavity, and hemothorax (also called hæmothorax), or blood in the chest cavity. A hemothorax, pneumothorax or both can occur if the chest wall is punctured.

Becauseof punctured chest wall, the lungs cannot expand, the pressure in the lungs never drops and no air is pulled into the bronchi. Respiration is not possible.

The function of respiratory system does not deal with the cleaning up of the air.

TV isapprox. 500 mL., i.e., a healthy man caninspire or expire approximately 6000 to 8000mL of air per minute. IRV averages 2500mL to 3000 mL.ERV averages 1000mL to 1100 mL. RV averages 1100 mL to 1200 mL.

Insects have spiracles on their exoskeletons to allow air to enter the trachea. In insects, the tracheal tubes primarily deliver oxygen directly into the insects' tissues. The spiracles can be opened and closed in an efficient manner to reduce water loss. This is done by contracting closer muscles surrounding the spiracle.

The larynx or the voice box is located at the upper end of the windpipe.

Aerobic respiration is the process of producing cellular energy involving oxygen. After glycolysis, pyruvate from glucose, the three-carbon molecule of pyruvic acid gets further broken down to give three molecules of carbon dioxide and water. This process takes place in the mitochondria of a cell in the presence of oxygen and energy is released. Plants and animals both undergo this type of respiration.

• The arytenoid cartilage is a pair of pyramid-shaped pieces of cartilage found in the larynx (voice box) and are essential for the production of voice/ vocal sound. 
• So, the correct answer is 'Larynx".

The laryngeal prominence (commonly referred to as Adam's apple), a feature of the human neck, is the lump or protrusion that is formed by the angle of the thyroid cartilage surrounding the larynx. The structure of the laryngeal prominence forms a bump under the skin. It is larger in adult men, in whom it is usually clearly visible and palpable. In women, the bump is much less visible and is hardly perceived on the upper edge of the thyroid cartilage. The laryngeal prominence is related to the deepening of the voice.

In a normal and healthy person, the haemoglobin is approximately 15gms per 100ml of blood. The capacity of 1gm of Hb is to combine with 1.36ml of oxygen. Thus, on an average, 100ml of blood carries about 19.4ml  of oxygen. It is called oxygen capacity of Hb. 

Lungs are the organs of ventilation in terrestrial animals. In humans, nostrils lead to trachea or wind pipe through nasopharynx. Trachea is a straight tube extending up to the mid-thoracic cavity, which divides at the level of 5th thoracic vertebra into a right and left primary bronchi. Each bronchi undergoes repeated divisions to form the secondary and tertiary bronchi and bronchioles ending up in very thin terminal bronchioles. The tracheae, primary, secondary and tertiary bronchi, and initial bronchioles are supported by incomplete cartilaginous rings. Each terminal bronchiole gives rise to a number of very thin, irregular walled and vascularised bag-like structures called alveoli. The branching network of bronchi, bronchioles, and alveoli comprise the lungs.

• Tidal Volume (TV) is the amount of volume of air that can be inspired/expired normally.
• Vital Capacity is the greatest volume of air that can be expelled from the lungs after taking the deepest possible breath.
• Residual volume is the volume of air still remaining in the lungs after the most forcible expiration possible. 
• Hence, option A is correct.