Respiratory system

• Human Anatomy and Physiology involves breathing and respiration.
• The respiratory system can alter your blood pH by changing the carbon dioxide levels.
• Air movement that passes through the vocal cords makes sound and speech possible.
• The respiratory system has innate immunity that protects us from some microorganisms and other pathogens such as viruses by preventing them from entering the body and removing them from respiratory surfaces.
• The respiratory system involves the exchange of oxygen and carbon dioxide between the atmosphere, blood, and cells.
• External respiration is gas exchange between the air in the lungs and the blood.
• Internal respiration is gas exchange between the blood and the tissues.
• The movement of air into and out of the lungs is part of the respiratory system.
• The upper respiratory tract consists of the external nose, nasal cavity, pharynx, and larynx.
• The lower respiratory tract consists of the trachea, the bronchi and smaller bronchioles, and the lungs.
• The conducting zone is exclusively for air movement and extends from the nose to the bronchioles.
• The respiratory zone is within the lungs and is where gas exchange between air and blood takes place.
• The respiratory zone consists of the external nose and the nasal cavity.
• The external nose forms the prominent features in face and is made of hyaline cartilage plates and nasal bones.
• Residual Volume (RV) is the volume of air still remaining in the respiratory passages and lungs after the most forceful expiration, approximately 1200 mL.
• Inspiratory Reserve Volume (IRV) is the amount of air that can be inspired forcefully after inspiration of the tidal volume, approximately 3000 mL at rest.
• Total Lung Capacity (TLC) is the sum of the inspiratory and expiratory reserve volumes plus the tidal volume and the residual volume, approximately 5800 mL.
• Vital Capacity (VC) is the sum of the inspiratory reserve volume, the tidal volume, and the expiratory reserve volume, which is the maximum volume of air a person can expel from the respiratory tract after a maximum inspiration, approximately 4600 mL.
• Functional Residual Capacity (FRC) is the expiratory reserve volume plus the residual volume, which is the amount of air remaining in the lungs at the end of a normal expiration, approximately 2300 mL at rest.
• Inspiratory Capacity (IC) is the tidal volume plus the inspiratory reserve volume, which is the amount of air a person can inspire maximally after a normal expiration, approximately 3500 mL at rest.
• Expiratory Reserve Volume (ERV) is the amount of air that can be forcefully expired after expiration of the tidal volume, approximately 1100 mL at rest.
• The nasal cavity is a passageway of air and functions to clean the air, humidify and warm air, and contain the olfactory epithelium.
• The external nares (nostrils) are the external openings into the nasal cavity.
• The internal nares or choanae are openings into the pharynx.
• The vestibule is the anterior part of the nasal cavity and is lined with stratified squamous with coarse hairs called vibrissae.
• The hard palate forms the floor of the nasal cavity and is formed by the maxilla and palatine bone.
• The nasal septum is a partition dividing the nasal cavity into right and left parts, with the anterior part being cartilage and the posterior part being the vomer and ethmoid bone.
• In adults, the reflex is important only when the tidal volume is large, such as during exercise.
• Normal value for physiological dead space is 0.8 mL V/Q MISMATCH refers to dead space where well ventilated, decreased perfusion (high V/Q) or well perfused, decreased ventilation (low V/Q) occurs.
• Minute ventilation is the total amount of air moved into and out of the respiratory system each minute, equal to the tidal volume times the respiratory rate.
• Tidal volume is the volume of air inspired or expired with each breath, at rest, quiet breathing results in a tidal volume of approximately 500 mL.
• Both reflexes dislodge foreign matter or irritating material from the respiratory passages.
• Cough reflex involves approximately 2.5 L of air being inspired, the vestibular and vocal folds close tightly to trap the inspired air in the lungs, the abdominal muscles contract to force the abdominal contents up against the diaphragm and the muscles of expiration contract forcefully, increasing the pressure in the lungs to 100 mm Hg or more, causing the vestibular and vocal folds to open suddenly, elevating the soft palate, and expelling air from the lungs at a high velocity, carrying foreign particles with it.
• Respiratory rate, or respiratory frequency, is the number of breaths taken per minute, approximately 12 breaths per minute.
• Physiological dead space is anatomical dead space plus the volume of any alveoli in which gas exchange is less than normal (under perfused or malfunctioning).
• Sneeze reflex occurs in the nasal passages and the soft palate is depressed, so that air is directed primarily through the nasal passages, although a considerable amount passes through the oral cavity.
• The part of the respiratory system where gas exchange does not take place is known as anatomical dead space.
• Pulmonary volumes and capacities are measured using a spirometer.
• Photic sneeze reflex, which affects 17-25% of the population, is stimulated by exposure to bright light, such as the sun, and results in an ACHOO sound.
• Action potentials have an inhibitory influence on the respiratory center and result in expiration.