Circulatory Physiology

• Airway resistance is measured in cm H2O/L/sec, not in terms of air volume. Understanding airway resistance helps assess respiratory function. [Q3193]
• Airway resistance refers to the resistance of the respiratory tract to airflow. It is distinct from the volume of air moved. [Q3194]
• Physiologic dead space is the sum of anatomic and alveolar dead spaces. This concept is crucial for understanding ventilation efficiency. [Q3259]
• Breathing into a paper bag helps calm the mind and restore normal breathing patterns. This method can alleviate hyperventilation symptoms. [Q3387]
• Functional residual capacity is the term for the air left in the lungs after normal expiration. It is important for maintaining adequate gas exchange between breaths. [Q3398]
• Endothelial cells secrete nitric oxide and prostacyclin as vasodilators. These substances help regulate blood flow and blood pressure. [Q3676]
• Erythrocytes are the main type of blood cells in all humans. They are essential for oxygen transport throughout the body. [Q3690]
• Approximately 350ml of fresh air enters the alveoli in one inspiration. This volume is vital for efficient gas exchange in the lungs. [Q3783]
• Fresh air entering the alveoli is calculated as tidal volume minus anatomic dead space. This calculation helps determine effective ventilation. [Q3784]
• Approximately 150ml of air is left in the airways as the anatomic dead space. Anatomic dead space impacts the efficiency of pulmonary ventilation. [Q3789]
• Functional residual capacity (FRC) is the volume of air remaining in the lungs after a normal expiration. FRC is important for maintaining continuous gas exchange. [Q3793]
• The normal hemoglobin ranges are 12-16 g/dL for females and 14-18 g/dL for males. Hemoglobin levels are essential for evaluating oxygen-carrying capacity. [Q3859]
• Hemoglobin can bind to four oxygen molecules. This binding capacity is crucial for efficient oxygen transport in the blood. [Q3860]
• Transfusion is typically considered when blood loss reaches around 1500 ml or more. Understanding this threshold helps manage significant blood loss effectively. [Q3939]
• The Fick principle is a method to measure cardiac output. This principle is fundamental for assessing heart function. [Q3954]
• Hyperkalaemia refers to an elevated level of potassium in the blood. High potassium levels can affect cardiac function. [Q3967]
• The normal alveolar ventilation rate in an adult is about 7000 ml per minute. Adequate ventilation rate is crucial for effective gas exchange. [Q4050]
• During heavy exercise, airflow can increase significantly, and blood flow can increase up to five-fold. These changes support increased metabolic demands. [Q4084]
• Gas exchange by diffusion primarily takes place in the alveoli. Efficient alveolar gas exchange is essential for oxygenating blood. [Q4132]
• Macrophages in the airways and alveoli help destroy inhaled particles and bacteria. These cells are key for maintaining respiratory health. [Q4289]
• Mean arterial pressure is calculated as Diastolic + 1/3 (systolic – diastolic). This calculation provides an average blood pressure in the arteries. [Q4317]
• Most oxygen exchange occurs in the alveoli. Alveoli are specialized structures for efficient gas exchange. [Q4385]
• The normal pH of blood is approximately 7.4. Maintaining this pH is critical for physiological homeostasis. [Q4596]
• Albumin and other plasma proteins help maintain osmotic pressure. This pressure is essential for fluid balance between blood and tissues. [Q4625]
• The average respiratory rate for adults is 12-20 breaths per minute. This rate is a vital sign indicating respiratory health. [Q4716]
• Children typically have a respiratory rate of 30-40 breaths per minute. Higher rates in children reflect their increased metabolic needs. [Q4717]
• Atrial natriuretic peptide is a vasodilator secreted by the atria. This peptide helps regulate blood pressure and fluid balance. [Q4915]
• Arterial baroreceptors located in the carotid sinuses and aortic arch play a significant role in blood pressure regulation. These receptors are crucial for maintaining cardiovascular stability. [Q4930]
• Capillaries lack smooth muscle, allowing for efficient exchange of substances between blood and tissues. This structural feature is vital for microcirculation. [Q4938]
• The expiratory reserve volume is the maximum amount of air expired after maximum activation of expiratory muscles. This volume reflects the reserve capacity of the lungs. [Q4999]
• Functional residual capacity can vary based on body size and other factors, making a single fixed value inaccurate. Understanding this variability is important for personalized respiratory assessments. [Q5023]
• Inspiratory reserve volume varies based on age, sex, and physical condition. This variability necessitates individualized respiratory evaluations. [Q5058]
• Norepinephrine is responsible for closing precapillary sphincters. This neurotransmitter helps regulate blood flow distribution. [Q5782]
• Veins are capacitance vessels that hold most of the blood volume. They play a key role in regulating blood return to the heart. [Q5811]
• The aorta has the most elastic walls to accommodate the high pressure of blood pumped from the heart. This elasticity is crucial for maintaining consistent blood flow. [Q5876]
• Veins hold the most blood volume, often referred to as capacitance vessels. Their capacity allows for effective blood volume regulation. [Q5877]
• The aorta is more elastic to handle the high pressure from the heart. This elasticity helps in dampening the pressure fluctuations from the cardiac cycle. [Q5878]
• Lymphatics carry filtered fluid from tissues back into the bloodstream. This function is essential for fluid balance and immune response. [Q5879]
• Sodium is the primary extracellular cation. Its distribution is crucial for maintaining osmotic balance and cell function. [Q5880]
• Potassium is the primary intracellular cation. It plays a vital role in cellular functions, including maintaining electrical gradients. [Q5881]
• Red blood cells carry oxygen and nutrients throughout the body. They are essential for delivering oxygen to tissues and removing carbon dioxide. [Q5882]
• Mast cells release histamine during inflammatory and allergic responses. Histamine release contributes to vasodilation and increased vascular permeability. [Q5883]
• Erythrocytes (red blood cells) lack a nucleus when mature to maximize space for hemoglobin. This adaptation allows for efficient oxygen transport. [Q5884]
• Fibroblasts are predominant in the periodontal ligament, providing structural support. They are essential for maintaining the integrity of periodontal tissues. [Q5885]
• Neutrophils are the primary cells present in acute inflammation. They are the first responders to infection and tissue damage. [Q5886]
• Monocytes and lymphocytes are predominant in chronic inflammation. These cells play a role in ongoing immune responses and tissue repair. [Q5887]
• Veins have softer walls compared to arteries. This structural difference allows veins to accommodate larger volumes of blood. [Q5942]
• Lymphatic vessels carry filtered fluid and are crucial for the immune system. They help return excess interstitial fluid to the bloodstream. [Q6080]
• Arterioles play a significant role in thermoregulation by controlling blood flow to the skin. This regulation helps maintain body temperature. [Q6081]
• Cutaneous arterioles regulate temperature in the skin by adjusting blood flow. This function is vital for thermoregulation and skin health. [Q6082]