66 Questions
What does FEV1 measure?
Volume expired in 1 second during forced expiration
What ratio is used as a marker of pulmonary function?
Ratio of total volume expired to volume expired in 1 second
What type of behavior acts to minimize disruption to set points?
Feedforward behavior
What does a ratio of total volume expired to volume expired in 1 second indicate?
Pulmonary function
Which feedback mechanism cancels the change in a variable?
Negative feedback
At what level of total volume expired is a medical emergency indicated?
Above 6.5MM
What is the function of negative feedback mechanisms in the body?
To cancel the change in a variable and maintain homeostasis
Which cell type is responsible for excitable signaling in the body?
Neural cells
What is the primary function of the integumentary system?
Protection and temperature regulation
What is the normal range of plasma K+ levels in the body?
3.5-4.5 mM
What is the role of CO2 in the body?
To prevent acidosis by being eliminated from the body
Which fluid compartment in the body contains the highest volume of water?
Intracellular fluid (ICF)
What is the primary function of muscle cells in the body?
To contract and generate force
Which system in the body is responsible for gas exchange?
Respiratory system
What is the main function of the nervous system in controlling breathing?
Sensing and responding to changes in blood CO2 and O2 levels
What is the equation for minute ventilation?
Minute ventilation = Tidal Volume $\times$ Respiratory Rate
What is the equation for Total Lung Capacity (TLC)?
TLC = Vital Capacity + Residual Volume
What does Forced Expiratory Volume in 1 second (FEV1) assess?
Pulmonary function
What is the typical anatomical dead space volume?
150ml
What is the equation for calculating partial pressures driving gas diffusion across alveolar membranes?
Partial pressure = Concentration $\times$ Gas constant
What happens in restrictive lung diseases?
TLC < 80% of normal
What is the effect of obstructive and chronic obstructive pulmonary diseases (COPD) on forced vital capacity (FVC)?
Reduce FVC
What is the typical vital lung capacity for men compared to women?
Men typically have larger vital lung capacities than women: ~ female < 4 L # male > 4 L
How many lobes does the right lung have compared to the left lung?
The right lung has 3 lobes, but the left lung has 2 lobes
Where does gas exchange take place in the respiratory system?
Gas exchange takes place in the alveoli
How many tiny alveoli air sacs are present in the lungs?
Lungs contain about 500 million tiny alveoli air sacs
What maximizes gas exchange in the alveoli?
The alveolar epithelium maximises gas exchange: ~ large surface area (100 – 140 m^2) ~ a thin cellular membrane (0.5 µm)
What do the primary bronchi divide into?
Primary bronchi divide to form secondary, tertiary bronchi etc
What is the size difference between vital lung capacities of men and women?
The difference in vital lung capacities between men and women is about 1.5 L
What is the primary function of alveolar epithelial Type II cells?
Secrete surfactant to reduce surface tension
What is the main stimulus for inspiration?
High blood CO2 levels
What is the equation for transpulmonary pressure (Ptp)?
$P_{tp} = P_{alv} - P_{ip}$
What is the typical tidal volume (Vt) at rest?
500 ml
What is the primary function of the pons in the respiratory system?
Enables voluntary control and smooths the transition between breathing in and out
What happens to airway resistance when the diameter of the airway is increased?
Airway resistance is reduced
What is the equation for minute ventilation?
$ ext{Minute ventilation} = ext{Tidal volume} imes ext{Respiratory rate}$
What is the approximate difference in vital lung capacities between men and women?
1.5 L
How many lobes does the right lung have?
3
What do terminal bronchioles divide into?
Respiratory bronchioles
Where does gas exchange take place in the respiratory system?
Alveoli
What is the approximate width of alveoli air sacs?
250 µm
What maximizes gas exchange in the alveoli?
Large surface area and thin cellular membrane
How many tiny alveoli air sacs are present in the lungs?
About 500 million
Which process is primarily responsible for maintaining high oxygen levels and low carbon dioxide levels at respiratory surfaces?
Physical ventilation
What is the main stimulus for inspiration?
High blood CO2 levels
What is the function of alveolar epithelial Type II cells?
Secrete surfactant to reduce surface tension
What determines the direction of air flow into and out of the alveoli?
Alveolar pressure relative to atmospheric pressure
What is the typical tidal volume at rest for an adult?
$500$ ml
What measure indicates the maximum volume of air a person can expel from the lungs after first filling them to maximum capacity?
Vital capacity (VC)
What is the primary role of the pons in the respiratory system?
Enabling voluntary control and smoothing the transition between breathing in and out
What is the primary role of glucagon in blood sugar regulation?
Stimulating the breakdown of glycogen into glucose in the liver
Where does fat bypass the liver to enter circulation?
Intestinal lymphatics
What is the main function of the enteric nervous system (ENS) in the gastrointestinal tract?
Control the passage of ingested substances
How is non-fat, water-soluble foodstuff absorbed by the body?
Via the liver through portal venous blood
What is the primary function of insulin in controlling blood glucose levels?
Increases glucose uptake into the cells
What is the process called when glucose is produced from amino acids?
Gluconeogenesis
What is the primary function of glucagon in controlling blood glucose levels?
Stimulates the release of glucose from glycogen stored in the liver
What is the approximate normal range for blood glucose levels post meal?
~140-160 mg/dL
What is the primary function of the kidneys in the renal system?
Filtration of metabolic wastes
What is the functional unit aiding filtration in the kidneys?
Glomerulus
What represents a bundle of interconnecting capillaries in the renal corpuscle?
Glomerulus
What is the movement in the renal corpuscle via, emptying via an efferent arteriole?
Glomerulus
What is the primary mechanism of movement during glomerular filtration?
Bulk flow
What occurs when a substance is moved from the tubular lumen into the peritubular capillaries?
Tubular reabsorption
What is the equation for renal clearance?
$ ext{Mass of substance excreted per unit time} / ext{plasma concentration of substance}$
What is the primary purpose of the renal pelvis in the renal system?
Collection of filtrate from the collecting ducts
Study Notes
Respiratory System and Gas Exchange
- Total Lung Capacity (TLC) is 4L, determined by Vital Capacity (VC) and Residual Volume (RV).
- Minute ventilation is the total amount of air inspired per minute, calculated as Tidal Volume x Respiratory Rate.
- Anatomical dead space is typically 150ml, affecting alveolar ventilation.
- Forced expiratory volume in 1 second (FEV1) assesses pulmonary function, with >80% indicating healthy lungs.
- Acid-base disorders can result from insufficient or excess breathing, leading to respiratory acidosis or alkalosis.
- Restrictive lung diseases result in TLC < 80% of normal, seen in respiratory distress syndromes and pulmonary fibrosis.
- Obstructive and chronic obstructive pulmonary diseases (COPD) reduce forced vital capacity (FVC), seen in asthma, cystic fibrosis, emphysema, bronchitis, and pneumonia.
- Lung cancer, emphysema, and bronchitis are often due to smoking.
- The circulatory system delivers oxygen to tissues and removes carbon dioxide.
- Partial pressures drive the diffusion of gases across alveolar membranes, with O2 and CO2 diffusing rapidly down their gradients.
- Adult hemoglobin has 4 protein subunits and carries oxygen to tissues, with O2 pick-up in the lungs and O2 release to cells in tissues.
- Myoglobin, with high O2 affinity, stores oxygen for muscle use during anaerobic metabolism.
Test your knowledge of pulmonary function testing and the forced expiratory volume in 1 second (FEV1) with this quiz. Explore the relationship between FEV1 and vital capacity, and understand its significance as a marker of pulmonary function. Challenge yourself to identify healthy and emergency FEV1 levels, and grasp the concept of feedback mechanisms in maintaining pulmonary homeostasis.
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