Free Digestion MCQs with Answers
680 Digestion MCQs from Biology, each with the correct answer and a written explanation of why it is correct. Free and unlimited, with no account needed.
The human digestive system covers the organs from mouth to anus, the movement of food, and the mechanical and chemical breakdown of carbohydrates, proteins and fats. It also includes the roles of digestive enzymes, bile, absorption through intestinal villi, and the assimilation of nutrients by body cells.
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Read the Digestion notesFree MDCAT chapter notes with key terms680 questions · page 18 of 34
- A. Pleura
- B. Chest cavity
- C. Diaphragm
- D. Inter-coastal muscle
Explanation: The diaphragm is a thin skeletal muscle that sits at the base of the chest and separates the abdomen from the chest.
Correct answer: Diaphragm- A. Tracheal cells
- B. Goblet cells
- C. Surfactant cells
- D. Pleural cells
Explanation: Goblet cells are unicellular structures which present in respiratory system and secrete mucus.In the respiratory system, goblet cells are…
Correct answer: Goblet cells- A. CO2
- B. O2
- C. Dust
- D. CO
Explanation: Cilia play a crucial role in helping to remove dust and other foreign particles from the respiratory system.Tiny hairs called cilia…
Correct answer: Dust- A. Glycolipids
- B. Nucleoproteins
- C. Glycoproteins
- D. Lipoproteins
Explanation: Surfactants are compounds that lower the surface tension (or interfacial tension) between two liquids, between a gas and a liquid, or…
Correct answer: Lipoproteins- A. Bronchi
- B. Alveoli
- C. Bronchioles
- D. Trachea
Explanation: Surfactant (the mixture of lipoproteins) is produced by the secretory cells of the alveolar epithelium.
Correct answer: Alveoli- A. Filtration of blood
- B. Increase gas exchange
- C. Reduce surface tension
- D. Act as antiseptic
Explanation: Surfactants is a lipoprotein layer inside alveoli, which reduce surface tension between water molecules to increase gases exchange.
Correct answer: Filtration of blood- A. 15 times per minute
- B. 20 times per minute
- C. 30 times per minute
- D. 25 times per minute
Explanation: A rest, we inhale and exhale 15_20 times per minute. During exercise, the breathing rate may rise to 30 times per minute
Correct answer: 30 times per minute- A. Chemical
- B. Physical
- C. Potential
- D. Mechanical
Explanation: Over all process of breathing is active and consumes energy during inspiration in the form of ATP
Correct answer: Chemical- A. Inspired air contains more O2 than exhaled air:
- B. Expired air has 100 times greater CO2 as inspired air
- C. Amount of N2 is equal in both inhaled and exhaled air
- D. Exhaled air is comparatively drier and inhaled air
Explanation: Exhaled air has saturated water contents as compared to inhaled air which has variable water contents.
Correct answer: Exhaled air is comparatively drier and inhaled air- A. CO
- B. O2
- C. N2
- D. CO2
Explanation: Highest concentration in inhaled air and exhaled air is that of N2, that is 79%.
Correct answer: N2- A. Inspired air
- B. Alveolar air
- C. Expired air
- D. Oxygenated blood
Explanation: Oxygen is 21% in inhaled airand it is 16% in exhaled air.
Correct answer: Inspired air- A. Lungs
- B. Intercostal muscles
- C. Diaphragm
- D. Pleura
Explanation: Lungs neither pull air in nor can they push it out. During inspiration passive expansion of lungs occures and expiration is due to passive…
Correct answer: Lungs- A. CO2 partial pressures in the blood
- B. H+ concentration in.the blood
- C. O2 partial pressures in the blood
- D. Blood glucose level
Explanation: •The rate of breathing is primarily regulated by the respiratory centers in the medulla oblongata and pons, which respond to chemical…
Correct answer: Blood glucose level- A. Increase, decrease
- B. Increase, increase
- C. Decrease, increase
- D. Decrease, decrease
Explanation: If we hold our breath for a long time, then due to increased metabolic actvity CO2 level will increase and pH will decrease.
Correct answer: Increase, decrease- A. Four phases
- B. One phase
- C. Three phases
- D. Two phases
Explanation: Breathing is mechanical process consisting of two phases i.e.inspiration and expiration.
Correct answer: Two phases- A. Emphysema
- B. Respiratory distress syndrome
- C. Bronchitis
- D. Asthma
Explanation: Respiratory distress syndrome (RDS) occurs primarily in premature infants who have not yet produced enough surfactant in their lungs.
Correct answer: Respiratory distress syndrome- A. Increased pressure
- B. Relaxation of the external intercostal muscle
- C. The relaxation of the muscle of the diaphragm
- D. The contraction of the muscles of the diaphragm
Explanation: During inspiration muscles of ribs and diaphragm contract due to whiclh ribs are elevated and diaphragm become less dome shaped.
Correct answer: The contraction of the muscles of the diaphragm- A. Surface area
- B. Thickness of the membrane
- C. Difference in concentration
- D. Presence of moisture
Explanation: Explanation: 1. Surface area (Option a): Diffusion of respiratory gases is directly proportional to the surface area available for gas…
Correct answer: Thickness of the membrane- A. O2 concentration in venous blood
- B. CO2 concentration in venous blood
- C. CO2 concentration in arterial blood
- D. O2 concentration in arterial blood
Explanation: The body's respiratory centre in the medulla is normally stimulated by an increased concentration of carbon dioxide, and to a lesser…
Correct answer: CO2 concentration in venous blood- A. Alveolar Air
- B. Arterial Blood
- C. Venous Blood
- D. Expired Air
Explanation: The partial pressure of oxygen in maximum in the expired air (116 mm Hg) because during expiration the oxygen that could not be inhaled…
Correct answer: Expired Air