Apii Final - Q. 1-95

The correct answer is "both is in the pons and inhibits the apneustic center." The pneumotaxic center is located in the pons, which is a region of the brainstem. It plays a role in regulating the rate and depth of breathing. Additionally, the pneumotaxic center inhibits the apneustic center, which is also located in the pons. This inhibition helps to regulate the inspiratory and expiratory phases of respiration, preventing prolonged inspiratory gasps.

The olfactory epithelium is not involved in providing chemoreceptor input to the respiratory centers of the medulla oblongata. The medullary chemoreceptors, aortic body, and carotid body all play a role in detecting chemical changes in the blood and providing input to the respiratory centers.

The renal pelvis is the cavity of the kidney that receives urine from the calyces. It is a funnel-shaped structure that is located at the innermost part of the kidney. The calyces collect urine from the renal pyramids and transport it to the renal pelvis, which then funnels the urine into the ureter for elimination from the body. The renal pelvis acts as a reservoir for urine and helps in its transportation.

The structure labeled "9." in the given options is the renal pelvis.

The glomerular (Bowman's) capsule and the glomerulus together form the renal corpuscle. The renal corpuscle is a part of the nephron, which is the functional unit of the kidney. It is responsible for the initial filtration of blood and the formation of urine. The glomerulus is a network of capillaries where filtration occurs, and the glomerular capsule surrounds and collects the filtered fluid. Therefore, the renal corpuscle is the correct answer as it accurately describes the structure formed by the glomerular capsule and glomerulus.

The correct answer is external intercostals. This can be determined by looking at Figure 20-2, which likely shows a diagram or illustration of the human body. The movement labeled "1" is most likely associated with the muscles located between the ribs, known as the intercostal muscles. Therefore, the external intercostals are the muscles responsible for producing this movement.

The term "external intercostal" refers to a muscle that is primarily involved in the process of inspiration, which is the act of inhaling air into the lungs. This muscle helps to elevate the ribcage, expanding the thoracic cavity and allowing for the intake of air. It is not an accessory muscle of expiration, as expiration is the act of exhaling air from the lungs. Additionally, it does not affect lung compliance or increase airway resistance. Therefore, the best description that matches the term "external intercostal" is "primary muscle of inspiration."

When a patient inhales as deeply as possible and then exhales as much as possible, the volume of air expelled is known as the vital capacity. Vital capacity is the maximum amount of air that can be exhaled after a maximum inhalation. It is calculated by adding the tidal volume, inspiratory reserve volume, and expiratory reserve volume. Therefore, the volume of air expelled in this scenario would be the patient's vital capacity.

The partial pressure of carbon dioxide in venous blood is approximately 45 mm Hg. This is because as blood flows through the tissues, carbon dioxide is produced as a waste product of cellular respiration. This carbon dioxide diffuses into the blood and is carried back to the lungs, where it is exhaled. The partial pressure of carbon dioxide in venous blood represents the pressure exerted by carbon dioxide molecules in the blood. It is lower than the partial pressure of carbon dioxide in arterial blood because some of the carbon dioxide has been exchanged for oxygen during the process of respiration.

Each 100 ml of blood leaving the alveolar capillaries carries away roughly 20 ml of oxygen. This is because the alveolar capillaries are responsible for the exchange of gases in the lungs. Oxygen from the inhaled air diffuses into the capillaries and binds to hemoglobin in red blood cells. This oxygen-rich blood then travels to the rest of the body to deliver oxygen to the tissues. Therefore, it can be concluded that approximately 20 ml of oxygen is carried by each 100 ml of blood leaving the alveolar capillaries.

The chloride shift is a physiological process that occurs in red blood cells (RBCs) during gas exchange in the lungs and tissues. It involves the movement of chloride ions into RBCs and bicarbonate ions into the plasma, facilitated by the chloride-bicarbonate counter-transporter. This shift is driven by a rise in PCO2, which promotes the conversion of carbon dioxide into bicarbonate ions in RBCs. The process does not cause RBCs to swell; instead, it helps maintain the shape and integrity of RBCs by balancing the movement of ions and maintaining osmotic equilibrium.

In connective tissue disease, the increased pulmonary vascular resistance causes the right ventricle to work harder to pump blood into the lungs. Over time, this increased workload can lead to the thickening of the right ventricular wall as a compensatory mechanism to handle the increased pressure and workload. This thickening helps to maintain adequate pumping function of the right ventricle.

If the dorsal respiratory group of neurons in the medulla oblongata were destroyed bilaterally, a person would stop breathing. The dorsal respiratory group is responsible for initiating the inspiratory phase of breathing by sending signals to the muscles involved in respiration. Without these neurons, the person would lose the ability to breathe voluntarily and would rely solely on reflexes to regulate their breathing, which would likely lead to respiratory failure and cessation of breathing.

Blocking afferent action potentials from the chemoreceptors in the carotid and aortic bodies would interfere with the brain's ability to regulate breathing in response to changes in PCO2. The chemoreceptors in these bodies are sensitive to changes in the partial pressure of carbon dioxide (PCO2) in the blood. When PCO2 levels rise, the chemoreceptors send signals to the brain, which then stimulates an increase in the rate and depth of breathing to remove excess carbon dioxide from the body. Blocking these action potentials would disrupt this feedback loop and prevent the brain from adequately responding to changes in PCO2 levels, leading to impaired regulation of breathing.

The expanded beginning of the ureter connects to the renal pelvis. The renal pelvis is a funnel-shaped structure that collects urine from the kidney and funnels it into the ureter. It is located at the innermost part of the kidney, within the renal sinus. The renal calyx is a cup-like structure that surrounds the renal pelvis and collects urine from the renal pyramids. The renal hilum is a concave area on the medial side of the kidney where the renal artery, renal vein, and ureter enter or exit. The renal corpuscle is a part of the nephron, responsible for filtering blood and forming urine.

The arrows labeled "6" and "7" indicate the movement of the ribcage during inhalation and exhalation. The rectus abdominis muscle contracts to pull down the ribcage during exhalation, while the internal intercostals muscle contracts to pull up the ribcage during inhalation. Therefore, both the rectus abdominis and internal intercostals muscles are involved in causing the movement indicated by the arrows.

Henry's law states that the volume of gas that will dissolve in a solvent is proportional to the partial pressure of that gas. This means that as the partial pressure of a gas increases, more of that gas will dissolve in the solvent. Conversely, if the partial pressure decreases, less gas will dissolve. This relationship is important in various fields, such as in the solubility of gases in liquids and in understanding gas exchange in biological systems.

Dalton's law of partial pressures states that in a mixture of gases, the total pressure exerted is equal to the sum of the individual partial pressures of each gas in the mixture. This means that each gas in the mixture contributes to the total pressure independently and does not affect the pressure exerted by the other gases present. This law is important in understanding the behavior of gases in mixtures and is used in various applications, such as in the study of atmospheric pressure and gas solubility.

The partial pressure of carbon dioxide in venous blood is the greatest among the options given. This is because carbon dioxide is produced as a waste product by cells during cellular respiration and is carried away from the tissues by the bloodstream. As it travels through the body, carbon dioxide accumulates in the venous blood, resulting in a higher partial pressure compared to other locations such as alveolar air, expired air, inspired air, and arterial blood.

Carbon dioxide is more soluble in water than oxygen, meaning it can dissolve more readily. In order to achieve the same amount of oxygen to dissolve in plasma as carbon dioxide, the partial pressure of oxygen would need to be increased or the partial pressure of carbon dioxide would need to be decreased. This is because increasing the partial pressure of oxygen would increase the driving force for oxygen to dissolve in plasma, while decreasing the partial pressure of carbon dioxide would decrease the competition for dissolved gas molecules in the plasma, allowing more oxygen to dissolve.

When the diaphragm and external intercostal muscles contract, it causes the thoracic cavity to expand. This expansion leads to an increase in the volume of the thorax. As the thorax expands, it creates more space for the lungs to expand and fill with air, allowing for inhalation to occur. Therefore, the correct answer is that the volume of the thorax increases.

Low pH alters hemoglobin structure, causing oxygen to bind less strongly to hemoglobin at low partial pressure of oxygen (PO2). This change in hemoglobin structure enhances the release of oxygen to tissues during internal respiration, where oxygen is unloaded from hemoglobin and taken up by cells. This process ensures that oxygen is efficiently delivered to the body's tissues for cellular respiration.

Stimulation of the apneustic center, which is located in the brainstem, would result in more intense inhalation. The apneustic center plays a role in controlling the depth and intensity of breathing by sending signals to the respiratory muscles. When it is stimulated, it causes a prolonged and intense activation of the inspiratory muscles, leading to a deeper inhalation. This can be seen as an increase in the strength and force of each breath taken.

The structure labeled "8." in the given options is the renal papilla. The renal papilla is the apex or tip of the renal pyramid, which is located in the renal medulla. It is responsible for collecting urine from the collecting ducts and transferring it to the renal pelvis.

Increasing the alveolar ventilation rate refers to increasing the amount of air that is brought into and out of the alveoli in the lungs. This increased ventilation rate allows for more efficient removal of carbon dioxide from the alveoli. As a result, the partial pressure of carbon dioxide in the alveoli decreases. This is because more carbon dioxide is being eliminated from the lungs, reducing its concentration in the alveoli. Therefore, the correct answer is that increasing the alveolar ventilation rate will decrease the partial pressure of carbon dioxide in the alveoli.

The pneumotaxic center of the pons is responsible for modifying the rate and depth of breathing. It works in coordination with the medulla, which controls the basic rhythm of breathing, to fine-tune the respiratory pattern. By adjusting the timing and intensity of inspiratory and expiratory signals, the pneumotaxic center helps regulate the overall rate and depth of breathing.

Internal respiration is the process by which dissolved gases, such as oxygen and carbon dioxide, are exchanged between the blood and the interstitial fluids. This occurs at the cellular level, where oxygen is taken up by the cells and carbon dioxide is released as a waste product. Pulmonary ventilation refers to the process of breathing, external respiration is the exchange of gases between the lungs and the blood, and cellular respiration is the process by which cells generate energy from glucose. Therefore, internal respiration is the correct answer as it specifically describes the exchange of gases between the blood and interstitial fluids.

The papillary duct delivers urine to a minor calyx. This duct is located in the inner medulla of the kidney and is responsible for transporting urine from the collecting ducts to the minor calyx, which is the first part of the renal pelvis. The other options listed are not involved in the transport of urine to the minor calyx. The nephron loop (loop of Henle) is responsible for reabsorbing water and ions from the filtrate, the distal convoluted tubule is involved in further reabsorption and secretion, the renal corpuscle is responsible for filtration, and the ureter transports urine from the kidneys to the bladder.

The partial pressure of oxygen in the interstitial space of peripheral tissues is approximately 40 mm Hg. This is because oxygen is delivered to the tissues through the bloodstream, and as it diffuses from the capillaries into the interstitial space, its partial pressure decreases. This decrease in partial pressure is due to the consumption of oxygen by the cells in the tissues. Therefore, the partial pressure of oxygen in the interstitial space is lower than in the arterial blood, which is typically around 100 mm Hg.

The inflation reflex is a protective mechanism that prevents the lungs from being over-inflated. When the lungs are filled with too much air, this reflex causes the muscles involved in breathing to relax, allowing the excess air to be expelled. This prevents damage to the delicate lung tissues and maintains the optimal level of inflation for proper gas exchange.

The fibrous capsule is the correct answer because it is the outermost layer of the kidney. It is a tough, fibrous membrane that surrounds and protects the kidney. The renal cortex is the next layer beneath the fibrous capsule, followed by the renal medulla. The major calyx and renal pelvis are internal structures of the kidney and are not part of the outermost layer.

External respiration refers to the process of exchanging gases between the lungs and the bloodstream. In this process, oxygen is taken in from the air into the alveoli (tiny air sacs in the lungs) and diffuses across the alveolar membrane into the bloodstream. At the same time, carbon dioxide, a waste product of metabolism, diffuses from the bloodstream into the alveoli to be exhaled. This exchange of gases occurs due to the difference in partial pressure of oxygen and carbon dioxide between the alveoli and the circulating blood. Therefore, the correct answer is the diffusion of gases between the alveoli and the circulating blood.

The pneumotaxic centers in the pons are responsible for regulating the respiratory rate and depth. They receive input from the hypothalamus and cerebrum, which helps in modifying the respiratory pattern. Additionally, these centers inhibit the apneustic centers, which are responsible for promoting passive or active exhalation. Therefore, all of the given options are correct explanations for the role of pneumotaxic centers in the pons.

Major calyces are large tributaries of the renal pelvis. The renal pelvis is a funnel-shaped structure that collects urine from the kidney and transports it to the ureter. The major calyces are the main branches that receive urine from the minor calyces, which in turn collect urine from the renal pyramids. Therefore, major calyces can be considered as large tributaries that help in the drainage of urine from the kidney.

The rate of external respiration is influenced by several factors including the PO2 of the alveoli, PCO2 of the blood, thickness of the respiratory membrane, and solubility of oxygen in plasma. However, the diameter of an alveolus does not directly affect the rate of external respiration. The diameter of an alveolus may impact the efficiency of gas exchange within the alveoli, but it does not directly affect the overall rate of external respiration.

In order for maximum loading of hemoglobin with oxygen to occur at the lungs, the PCO2 (partial pressure of carbon dioxide) should be low. This is because high levels of PCO2 indicate that there is an excess of carbon dioxide in the blood, which can lead to a decrease in the affinity of hemoglobin for oxygen. Therefore, to maximize the binding of oxygen to hemoglobin, it is necessary for the PCO2 to be low.

Higher brain centers, such as the cortical association areas, the limbic system, the hypothalamus, and Broca's center, play a role in altering the activity of the respiratory centers. However, the precentral motor gyrus is not involved in this process.

The apneustic centers of the pons inhibit the pneumotaxic center. This means that they suppress the activity of the pneumotaxic center, which is responsible for regulating the duration and depth of each breath. By inhibiting the pneumotaxic center, the apneustic centers prolong the inspiratory phase of respiration, leading to longer and deeper breaths.

The collecting ducts are largely confined to the renal medulla. The collecting ducts are responsible for reabsorbing water and concentrating the urine. They receive urine from multiple nephrons and carry it through the renal medulla to the renal pelvis. This allows for the concentration of waste products and the reabsorption of water, helping to maintain the body's water balance. The other components mentioned, such as the glomerular (Bowman's) capsule, distal convoluted tubule, proximal convoluted tubule, and glomerulus, are located in different parts of the nephron but are not primarily confined to the renal medulla.

The correct answer is "amount of air reaching the alveoli each minute." Alveolar ventilation refers to the movement of air into and out of the lungs, specifically the amount of air that reaches the alveoli, which are tiny air sacs in the lungs where gas exchange occurs. This measure is important because it determines how much fresh oxygen is available for the body and how much carbon dioxide is removed.

Alveolar ventilation rate is the correct answer because it is the product of the respiratory rate multiplied by the difference between the tidal volume and the anatomic dead space. This calculation represents the amount of fresh air that reaches the alveoli per minute, which is important for efficient gas exchange in the lungs. Vital capacity refers to the maximum amount of air that can be exhaled after a maximal inhalation. Respiratory minute volume is the total amount of air inhaled and exhaled per minute. Pulmonary ventilation rate is the total volume of air inhaled and exhaled per minute. External respiration rate refers to the exchange of gases between the lungs and the blood.

The term calyx refers to the structure where the final urine enters. The calyx is part of the renal pelvis, which is responsible for collecting the urine produced by the kidneys. It acts as a funnel, allowing the urine to flow from the renal pyramids into the renal pelvis and eventually into the ureter. Therefore, the description "final urine enters here" best matches the term calyx.

The correct answer is apneustic. The apneustic center is responsible for stimulating the inspiratory neurons in the medulla oblongata, which helps regulate the rate and depth of breathing. It works in conjunction with other respiratory centers, such as the pneumotaxic center and the ventral respiratory group (VRG), to maintain a normal breathing pattern. The VRG controls the muscles involved in breathing, while the pneumotaxic center helps regulate the duration and intensity of each breath. However, neither the pneumotaxic nor the expiratory center alone establish the normal rate and depth of breathing, making them incorrect choices.

The term renal papilla refers to the tip of the medullary pyramid in the kidney. The medullary pyramids are triangular structures in the kidney that contain the collecting ducts, which are responsible for transporting urine. The renal papilla is where the final urine enters, as it is the endpoint of the collecting ducts. Therefore, the description "tip of the medullary pyramid" best matches the term renal papilla.

The partial pressure of oxygen in arterial blood is approximately 95 mm Hg. This is because oxygen is transported from the lungs to the body tissues through the arterial blood. In the lungs, oxygen diffuses from the alveoli into the blood, and it binds to hemoglobin in red blood cells. The oxygen-rich blood is then pumped by the heart to the rest of the body. The partial pressure of oxygen in arterial blood is highest because it is freshly oxygenated and has not yet reached the body tissues where oxygen is consumed.