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Structure and Function
of the Body: Chapter 15
Q & A graded A+
A 3-dimensional visual of the respiratory system would be similar to an - answer ✅✅inverted tree if it were hollow Branches would be the - answer ✅✅bronchi Leaves of the tree would be - answer ✅✅comparable to alveoli, with the microscopic sacs enclosed by networks of capillaries The passive transport process of diffusion is responsible for
- answer ✅✅the exchange of gases that occurs during respiration The respiratory tract is divided into - answer ✅✅upper and lower portions
The upper respiratory tract includes - answer ✅✅the nose, pharynx, and larynx The lower respiratory tract contains - answer ✅✅the trachea, bronchial tree, alveoli, and lungs The respiratory mucosa is a - answer ✅✅specialized membrane that lines the air distribution tubes in the respiratory tree Three types of epithelium are - answer ✅✅present in the respiratory mucosa Ciliated pseudostratified epithelium lines - answer ✅✅most of the tract and produces mucus Stratified squamous epithelium lines - answer ✅✅the nostrils, vocal folds, and pharynx; it serves a protective function Simple squamous epithelium lines - answer ✅✅the alveoli, and facilitates gas exchange More than 125 mL of mucus is produced each day - answer ✅✅The respiratory mucosa forms a "mucous blanket" over much of the respiratory mucosa
The pharynx functions as - answer ✅✅a passageway for food and liquids, as well as a passageway for air Nine pieces of cartilage form the - answer ✅✅framework of the last structure of the upper respiratory tract, the larynx The thyroid cartilage - answer ✅✅(also called the Adam's apple) is the largest of the nine pieces of cartilage The epiglottis partially covers the - answer ✅✅opening into the larynx Vocal cords stretch - answer ✅✅across the interior of the larynx One of the larynx's functions is - answer ✅✅voice production The other larynx's function is - answer ✅✅air distribution; like the pharynx, it serves as a passageway for air to move to and from the lungs The trachea is a tube about - answer ✅✅11 cm (or 4.5 in) long and 2.5 cm (or 1 in) in diameter The trachea extends from - answer ✅✅the larynx into the thoracic cavity
C-shaped rings of cartilage hold the - answer ✅✅trachea open, but allow for swallowing The trachea functions as - answer ✅✅a passageway for air to move to and from the lungs Blockage of the trachea - answer ✅✅occludes the airway and, if complete, causes death in minutes In fact, tracheal obstruction causes more than - answer ✅✅4,000 deaths annually in the United States The trachea branches into - answer ✅✅right and left bronchi Each bronchus branches into - answer ✅✅smaller and smaller tubes, eventually leading to bronchioles Bronchioles end in - answer ✅✅clusters of microscopic alveolar sacs, the walls of which are made up of alveoli The function of the bronchial tree is - answer ✅✅air distribution; it serves as a passageway for air to move to and from alveoli The function of alveoli is - answer ✅✅the exchange of gases between air and blood
External respiration is - answer ✅✅pulmonary ventilation (or breathing) and pulmonary gas exchange Pulmonary gases are - answer ✅✅transported by the blood, and serve a function in the regulation of set point levels of blood gases Internal respiration is the - answer ✅✅gas exchange between the blood and systemic tissues The term cellular respiration refers to - answer ✅✅the use of oxygen by cells in the process of metabolism Pulmonary ventilation includes two phases called - answer ✅✅inspiration (movement of air into lungs) and expiration (movement of air out of lungs) Inspiration is - answer ✅✅movement of air into lungs Expiration is - answer ✅✅movement of air out of lungs Changes in the size and shape of the thorax cause - answer ✅✅changes in air pressure within that cavity and in the lungs Pressure differences (or gradients) cause - answer ✅✅air to move into and out of the lungs
Inspiration is the - answer ✅✅active process whereby air moves into the lungs Inspiratory muscles include the - answer ✅✅diaphragm and external intercostals The diaphragm flattens when - answer ✅✅stimulated by the phrenic nerve during inspiration, which increases the top-to- bottom length of the thorax The external intercostal muscles - answer ✅✅contract and elevate the ribs, which increases the size of the thorax from the front to the back and from side to side Increase in the size of the chest cavity - answer ✅✅reduces pressure within it; air then enters the lungs by moving down its pressure gradient Quiet expiration is - answer ✅✅ordinarily a passive process During expiration, the thorax - answer ✅✅returns to its resting size and shape Elastic recoil of lung tissues - answer ✅✅aids in expiration Expiratory muscles used in forceful expiration are the - answer ✅✅internal intercostals and abdominal muscles
Residual volume is the - answer ✅✅air that remains in the lungs after the most forceful expiration Regulation of respiration permits the body to - answer ✅✅adjust to varying demands for oxygen supply and carbon dioxide removal by maintaining set point concentrations of blood gases Several mechanisms control respiration - answer ✅✅the brainstem, cerebral cortex and respiratory reflexes The most important central regulatory centers in - answer ✅✅both the medulla and pons in the brainstem are called respiratory control centers Under resting conditions the medullary rhythmicity area produces - answer ✅✅a normal rate and depth of respirations. A normal rate is considered to be 12 to 18 breaths per minute As conditions in the body vary, centers in the pons (called pontine centers) can - answer ✅✅alter the activity of the medullary rhythmicity area, thus adjusting breathing rhythm Brainstem centers are influenced by - answer ✅✅information from other parts of the brain and from sensory receptors located in other body regions Control of respiratory activity by the cerebral cortex is - answer ✅✅voluntary but limited
Respiratory reflexes include - answer ✅✅chemoreflexes and pulmonary stretch reflexes In chemoreflexes - answer ✅✅chemoreceptors respond to changes in carbon dioxide, oxygen, and blood acid levels; these receptors are located in carotid and aortic bodies Pulmonary stretch reflexes respond to the - answer ✅✅stretch receptors in lungs, thus protecting respiratory organs from overinflation Eupnea is - answer ✅✅normal breathing Hyperventilation means - answer ✅✅rapid and deep respirations Hypoventilation indicates - answer ✅✅slow and shallow respirations Dyspnea is - answer ✅✅labored or difficult respirations Apnea is - answer ✅✅stopped respiration, absence of breathing Respiratory arrest is the - answer ✅✅failure to resume breathing after a period of apnea
Oxygen moves - answer ✅✅out of tissue capillary blood into tissue cells (Systemic gas exchange, 2) Carbon dioxide moves from - answer ✅✅issue cells into tissue capillary blood (Systemic gas exchange, 3 ) Hemoglobin combines with carbon dioxide, forming - answer ✅✅carbaminohemoglobin (Systemic gas exchange, 4) Blood transportation of gases includes - answer ✅✅transport of oxygen and carbon dioxide Only small amounts of oxygen gas can be - answer ✅✅dissolved in blood. Most oxygen combines with hemoglobin to form oxyhemoglobin to be carried in the blood. Most oxygen combines with - answer ✅✅hemoglobin to form oxyhemoglobin to be carried in the blood Dissolved carbon dioxide is about - answer ✅✅10% of the total carbon dioxide transported in the blood Carbaminohemoglobin is about - answer ✅✅20% About 70% of the total carbon dioxide transported in the blood is carried in the form of - answer ✅✅bicarbonate ions
