MCQs on Human Physiology with Answer Key
The topic “Human Physiology” will help you to understand the functions and mechanisms of a human body involving organs, cells, blood, nerves, etc. which help to interact with our surroundings and carry on with our day to day activities. Under Human Physiology, one will also learn about the underlying physiological processes in detail. These include respiration, digestion, excretion and so on.
You will be able to gain a better understanding of this chapter once you start solving the physiology MCQs. The objective questions will help you to revise the topics while also strengthening your understanding of essential concepts. Keeping this in mind, the physiology MCQ questions have been selected carefully from all parts of the chapter to help you with your preparation.
Given below are physiology MCQs from the unit Human Physiology. You can opt to attempt all of the topics or test your understanding of a particular topic by going through the physiology questions from that specific section.
Multiple Choice Questions on Digestion and Absorption
Some of the questions related to the digestive system are mentioned below.
1. The hormone is secreted by which of the following organ?
Pancreas
Liver
Duodenum
Ans- a
Explanation- The pancreas is an organ that serves as a major endocrine gland; it secretes hormones like insulin, somatostatin and glucagon. It is important to note that the pancreas serves as both the exocrine and endocrine glands.
2. If the stool of a person is whitish-grey, which organ is responsible for it?
Kidney
Liver
Spleen
Ans- b
Explanation- The liver is the organ responsible for the white coloured faeces because of the low concentration of bile secretion.
3. A type of proteolytic enzyme is found in infants’ gastric juices which helps in the digestion of milk proteins. The name of the enzyme is?
Peptide
Rennin
Amylases
Ans- b
Explanation- Rennin, also known as chymosin, is a protein-digesting enzyme that causes milk to curdle by converting caseinogen into insoluble casein.
4. Fat digestion occurs in?
Small intestine
Stomach
Duodenum
Ans- a
Explanation- Fat digestion occurs in the small intestine of the human digestive system.
5. Protein digestion occurs in?
Rectum
Small intestine
Ileum
Ans- c
Explanation- Protein digestion begins in the stomach and continues in the small intestine. Amino acids are recycled by the organism in order to produce new proteins. The ileum is the site of protein digestion.
6. Which one of the following can be found in pancreatic juice?
Trypsinogen
Proenzyme pepsinogen
Lysozyme
Ans- a
Explanation- Trypsinogen is the inactive form of the hormone secreted by the pancreas, trypsinogen is converted into the active form, trypsin, by the action of enteropeptidase. Trypsin is involved in protein digestion.
MCQs on Breathing and Exchange of Gases
7. Respiratory centre is located in?
Cerebellum
Medulla oblongata
Cerebrum
Ans- b
Explanation- Medulla oblongata serves as the centre of respiratory regulation.
8. Carbon Monoxide poisoning happens due to?
Carbonic acid
Carboxy haemoglobin
Methane
Ans- b
Explanation- Carbon monoxide binds to haemoglobin with a significantly higher affinity than oxygen, resulting in the formation of carboxyhemoglobin (COHb) and reduced oxygen delivery. Carbon monoxide can potentially set off an inflammatory cascade in the CNS, resulting in lipid peroxidation and long-term neurologic consequences and carbon monoxide poisoning.
9. The internal lining in the trachea is made up of ?
Simple cuboidal epithelium
Pseudostratified epithelium
Simple squamous epithelium
Ans- b
Explanation- Pseudostratified epithelium forms the internal lining of the trachea.
10. A person has difficulty breathing due to inflammation of the bronchi and bronchioles. What does he or she has?
Emphysema
Occupational respiratory disorders
Asthma
Ans- c
Explanation- Asthma is a disorder that causes your airways to constrict and swell, as well as create excess mucus. This can make breathing difficult, resulting in coughing, whistling (wheezing) on exhalation, and shortness of breath. Asthma is a mild annoyance for some people.
MCQs on Excretory Products and Their Elimination
11. Kidney’s ability to produce concentrated urine depends on?
Diffusion
Active transport
Countercurrent mechanism
Ans- c
Explanation- A countercurrent mechanism system uses energy to build a concentration gradient, which allows you to reabsorb water from tubular fluid and produce concentrated urine. This system keeps you from creating litres upon litres of dilute pee every day, which is why you don't need to drink constantly to stay hydrated.
12. The right sequence of formation of urine is ?
Secretion, reabsorption, filtration
Reabsorption. Secretion, filtration
Filtration, reabsorption, secretion
Ans- c
Explanation- Filtration, reabsorption, secretion, is the sequence of events in the nephron that results in urine formation.
13. When an individual consumes a large amount of protein, what will he or she will excrete?
More urea and uric acid
More glucose
Salt
Ans- a
Explanation- More urea and uric acid is produced in the urine of a person who is intaking a protein-rich diet.
14. In the case of uricotelic animals, urea is removed via?
Ornithine cycle
Kreb’s cycle
Cori Cycle
Ans- a
Explanation- Urea is ureotelic animals' major nitrogenous excretory product. The urea cycle, also known as the Ornithine cycle or Krebs Henseleit cycle, is used by liver cells to manufacture it from deaminated excess amino acids.
MCQs on Body Fluids and Circulation
15. The life span of red blood cells is?
100 days
110 days
120 days
Ans- c
Explanation- 120 days is the maximum lifespan of an RBC.
16. The life span of white blood cells is?
Between 20-30 days
Between two to three months
Less than ten days
Ans- a
Explanation- The life span of white blood cells varies between 20-30 days.
17. What is the ratio of WBC to RBC in the body?
1:60
1:600
1:6000
Ans- b
Explanation- 1:600 is the normal ratio of WBC to RBC in the body. There is one WBC per 600 RBC.
18. Which is the largest blood vessel in the human body?
Pulmonary vein
Capillaries
Aorta
Ans- c
Explanation- The aorta is the major blood vessel that connects your heart to the rest of your body. The aortic valve is where blood leaves the heart. The blood next passes through the aorta, where it forms a cane-shaped curvature that permits other major arteries to supply oxygen-rich blood to the brain, muscles, and other cells.
19. Which of the following is responsible for the red colour of blood?
Hemocyanin
Myoglobin
Haemoglobin
Ans- c
Explanation- Haemoglobin is the protein found in the red blood cells, it primarily functions in the transport of oxygen and carbon dioxide. It renders red colour to the blood.
20. What should be the blood pressure of a healthy human being?
120/80
120/100
110/90
Ans- a
Explanation- 120/80 is the normal blood pressure measured in humans, 12 represents the systolic pressure while 80 represents the diastolic pressure.
MCQs on Locomotor and Movement in Humans
21. Which is a skull bone?
Arytenoid
Cricoid
Pterygoid
Ans- c
Explanation- The pterygoid is a skull bone.
22. Which body muscle can resist fatigue?
Voluntary
Striped
Cardiac
Ans- c
Explanation- Cardiomyocytes are extremely fatigue resistant. They, like other muscles, are largely fueled by mitochondria (the cell's energy house). Cardiomyocytes contain up to ten times the density of mitochondria, resulting in a massive increase in energy output.
MCQs on the Nervous System
23. In which area does the comprehension of spoken and written words take place?
Broca’s area
Wernicke’s area
Association area
Ans- b
Explanation- The Wernicke's area is a critical part of the brain for language development. It is responsible for speech comprehension and is located in the temporal lobe on the left side of the brain, whereas Broca's region is responsible for speech production.
24. Which of the following controls skeletal muscles?
Autonomic nerves
Somatic nerves
Sympathetic nerves
Ans- b
Explanation- The somatic nervous system, also known as the voluntary nervous system, is a portion of the peripheral nervous system that is responsible for the voluntary regulation of skeletal muscle contractions.
25. When Sympathetic Nerves get activated, it releases?
Adrenaline, which stimulates the organ
Adrenaline, which inhibits the organ
Acetylcholine, which stimulates the organ
Ans- (a)
Explanation- Adrenaline is a sympathetic nerve activator that stimulates the organ when secreted.
26. Which of the following is not a neurotransmitter?
Glutamic Acid
Acetylcholine
Tyrosine
Ans- (c)
Explanation- Tyrosine is an amino acid that does not act as a neurotransmitter.
27. Which of the following is the largest cranial nerve?
Oculomotor nerve
Olfactory nerve
Trigeminal nerve
Ans- (c)
Explanation- The trigeminal nerve is a component of the nervous system that transmits discomfort, pressure, and thermal impulses from the face to the brain. It's a big, three-part nerve.
Now that you have solved the Human Physiology MCQs, you will be able to ascertain your preparation level for exams for this unit.
FAQs on Human Physiology MCQs
1. What is Human Physiology and what major systems are covered in the Class 11 syllabus?
Human Physiology is the scientific study of the functions and mechanisms which work within a living human body. For Class 11 Biology, as per the CBSE 2025-26 curriculum, this unit explores how different organ systems work in coordination. The major systems include:
- Digestion and Absorption
- Breathing and Exchange of Gases
- Body Fluids and Circulation
- Excretory Products and their Elimination
- Locomotion and Movement
- Neural Control and Coordination
- Chemical Coordination and Integration
2. What are the main enzymes involved in digesting proteins, carbohydrates, and fats in the human body?
The digestion of macromolecules is carried out by specific enzymes. Key examples include:
- Proteins: Digestion starts in the stomach with Pepsin and continues in the small intestine with enzymes like Trypsin, Chymotrypsin, and Carboxypeptidases from the pancreas.
- Carbohydrates: Digestion begins in the mouth with Salivary Amylase and is completed in the small intestine by Pancreatic Amylase and other disaccharidases like maltase and lactase.
- Fats: Fat digestion primarily occurs in the small intestine, where fats are first emulsified by bile and then broken down by Lipases secreted by the pancreas.
3. How is breathing regulated by the brain?
The primary control centre for regulating breathing is the respiratory rhythm centre, located in the medulla oblongata region of the brainstem. This centre establishes the basic rhythm of inspiration and expiration. Another centre, the pneumotaxic centre in the pons, can moderate the functions of the respiratory rhythm centre to alter the breathing rate based on the body's needs.
4. What are the three key steps of urine formation in a nephron?
The formation of urine in the nephrons of the kidney involves three main processes that occur in a specific sequence:
- Glomerular Filtration: Blood is filtered under pressure from the glomerulus into the Bowman's capsule, separating water and small solutes from blood cells and proteins.
- Tubular Reabsorption: As the filtrate passes through the renal tubule, essential substances like glucose, amino acids, salts, and a majority of water are reabsorbed back into the blood.
- Tubular Secretion: Certain waste products like hydrogen ions, potassium ions, and ammonia are actively secreted from the blood into the filtrate to be eliminated in urine.
5. What is the difference between systolic and diastolic blood pressure?
Blood pressure is measured with two numbers, with a normal reading around 120/80 mm Hg. The difference is:
- Systolic Pressure (120 mm Hg): This is the higher number and represents the maximum pressure your heart exerts while beating to push blood through your arteries.
- Diastolic Pressure (80 mm Hg): This is the lower number and represents the amount of pressure in your arteries between beats, when the heart muscle is at rest.
6. How does the countercurrent mechanism in the kidney help in water conservation?
The countercurrent mechanism is an efficient system that helps produce concentrated urine, thus conserving water. It involves the flow of filtrate in opposite directions in the two limbs of the Henle's loop and the flow of blood in the vasa recta. This opposition creates and maintains a high concentration of solutes in the kidney's inner medulla. As the final urine passes through the collecting duct, this high concentration gradient pulls water out via osmosis, making the urine more concentrated than body fluids.
7. Why is carbon monoxide (CO) more dangerous than carbon dioxide (CO₂) in terms of its effect on haemoglobin?
Carbon monoxide (CO) is significantly more dangerous because it has an affinity for haemoglobin that is about 200-250 times higher than that of oxygen. When inhaled, CO binds tightly to haemoglobin to form a stable compound called carboxyhaemoglobin. This binding is very difficult to reverse and effectively blocks haemoglobin from carrying oxygen, leading to severe oxygen deprivation in tissues and potential death. Carbon dioxide, in contrast, binds much more loosely and is transported in different ways.
8. What is the functional difference between the somatic nervous system and the autonomic nervous system?
The key functional difference lies in the type of control they exert over body functions.
- The Somatic Nervous System (SNS) controls voluntary actions. It is responsible for carrying motor and sensory information to and from the central nervous system to control the skeletal muscles, such as when you decide to walk or talk.
- The Autonomic Nervous System (ANS) governs involuntary functions that are not under conscious control. This includes regulating heart rate, digestion, respiratory rate, and pupillary response.
9. How do cardiac muscles resist fatigue compared to other muscle types in the body?
Cardiac muscles, found in the heart, are exceptionally resistant to fatigue due to unique cellular adaptations. Their cells, called cardiomyocytes, have a much higher density of mitochondria than skeletal muscle cells. This abundance of mitochondria allows for continuous and efficient aerobic respiration, providing a constant supply of ATP (energy). Furthermore, cardiac muscles have a rich blood supply, ensuring constant delivery of oxygen and preventing the buildup of metabolic wastes that cause fatigue.
10. What is a common misconception about the digestion of fats?
A common misconception is that significant fat digestion begins in the stomach, similar to protein digestion. In reality, meaningful chemical digestion of fats does not occur until they reach the small intestine. The crucial steps of emulsification by bile salts (from the liver) and the enzymatic breakdown by pancreatic lipase happen almost exclusively in the duodenum, the first part of the small intestine.
