Respiratory system - Quiz

The medulla oblongata is located in the brainstem and is responsible for controlling involuntary activities such as breathing, heart rate, and blood pressure. The medulla contains specialized cells called respiratory centers that regulate the rate and depth of breathing based on the levels of carbon dioxide and oxygen in the body. The respiratory centers send nerve impulses to the muscles involved in breathing, including the diaphragm and intercostal muscles, to adjust the respiratory rate and depth. Therefore, option (c) is the correct answer.

When a person resides at higher altitudes, the air pressure and oxygen levels decrease. This triggers a response in the body to produce more RBCs to carry oxygen to the tissues. The hormone erythropoietin (EPO) is produced by the kidneys in response to low oxygen levels, which stimulates the bone marrow to produce more RBCs. This increase in RBC production helps to maintain adequate oxygen levels in the body tissues. As a result, the number of RBCs in the blood of a person residing at higher altitudes increases.

Lumen is not a part of the human respiratory system. It is a term used in anatomy to describe the inner space or cavity within a tubular structure. In contrast, the pharynx, alveoli, and trachea are all structures that play crucial roles in the respiratory system.
The pharynx is a muscular tube that connects the nasal cavity and mouth to the esophagus and trachea. It serves as a passageway for air and food.
The trachea, also known as the windpipe, is a tube that carries air from the pharynx to the bronchi of the lungs. It is made up of C-shaped rings of cartilage, which keep the trachea open.
The alveoli are small, air-filled sacs located at the end of the bronchioles in the lungs. They are the site of gas exchange between the air and the blood, allowing oxygen to enter the bloodstream and carbon dioxide to be removed.
In summary, the human respiratory system includes the pharynx, trachea, and alveoli, but not the lumen. The lumen belongs to the digestive system, where it plays a role in increasing the surface area for the absorption of food.

The endoderm is one of the three primary germ layers of the embryo, which gives rise to the epithelium of the pharynx, larynx, trachea, and lungs. Alveoli, which are the small air sacs in the lungs, are derived from the endoderm. The endoderm also gives rise to various other organs, including the thyroid gland, parathyroid glands, thymus gland, gastrointestinal tract, urinary bladder, vagina, and urethra.

The lungs are divided into two regions: the conducting zone and the respiratory zone. The conducting zone consists of the trachea, bronchi, and bronchioles and is responsible for air transport. The respiratory zone is where gas exchange occurs, and it includes the respiratory bronchioles, alveolar ducts, and alveoli. Gaseous exchange takes place in the respiratory region, specifically in the alveolar ducts and alveoli. These structures are surrounded by a network of capillaries where oxygen from the air is exchanged for carbon dioxide from the blood. Thus, option C is the correct answer.

Decrease in thoracic volume occurs during expiration, which is marked by the relaxation of the diaphragm and external intercostal muscles. During expiration, the pressure within the lungs must be higher than atmospheric pressure in order to push the air out. Relaxation of the diaphragm and external intercostal muscles leads to a decrease in thoracic volume and helps in building more pressure in the lungs. Therefore, option A is the correct answer.

During inspiration, the diaphragm contracts and moves downwards, causing an increase in the thoracic volume in the antero-posterior axis. This leads to an increase in the space available for the lungs to expand, allowing for the intake of air. The movement of the sternum during inspiration also causes an increase in the thoracic volume, but this occurs in the antero-ventral direction. The dorso-ventral and dorso-posterior axes do not experience significant changes in volume during inspiration.

The respiratory rhythm center is located in the medulla region of the brain. Specifically, it is located in the medullary reticular formation, which contains two groups of neurons known as the dorsal respiratory group (DRG) and the ventral respiratory group (VRG). The DRG is responsible for generating the basic respiratory rhythm, while the VRG remains inactive during normal respiration but can be activated during periods of increased respiratory demand or in response to certain stimuli. The respiratory rhythm center is responsible for regulating the rate and depth of breathing, and also receives input from various sensors in the body that detect changes in oxygen and carbon dioxide levels.

Dead space air is the air that remains in the lungs and does not participate in gas exchange. The volume of dead space air is approximately 150 CC. This air is trapped in the conducting airways such as the trachea, bronchi and bronchioles, and does not reach the alveoli where gas exchange takes place. This means that during each breath, some of the air that is inhaled does not contribute to the oxygenation of the blood. Dead space air can increase in conditions like chronic obstructive pulmonary disease (COPD) and pulmonary embolism, and can decrease with exercise and positive pressure ventilation.

The signal for voluntary muscle for forced breathing starts in the cerebrum. The cerebrum is the part of the brain responsible for conscious actions and voluntary movements. During forceful inspiration or expiration, the signals are generated through the cerebrum and sent to the respiratory muscles to increase the strength of breathing. This type of breathing is also known as "forced breathing" and is used in situations where more air needs to be taken in or expelled from the lungs, such as during exercise or in certain medical conditions.