Human Physiology MCQ Quiz - Objective Question with Answer for Human Physiology - Download Free PDF

The correct answer is A-III, B-I, C-IV, D-II

Explanation:

• Respiratory rhythm centre is primarily responsible for regulating respiratory rhythm
• Pneumotaxic centre present in the pons region of the brain can moderate the functions of the respiratory rhythm centre.
• A chemosensitive area is situated adjacent to the rhythm centre which is highly sensitive to CO2 and hydrogen ions.
• Receptors associated with aortic arch and carotid artery also can recognise changes in CO₂ and H+ concentration and send necessary signals to the rhythm centre for remedial actions.

• The regulatory mechanism of respiration involves multiple centers and receptors within the central nervous system and peripheral areas. The respiratory rhythm is primarily controlled by:
  • Respiratory rhythm centre in the medulla oblongata, which generates the basic rhythm of respiration.
  • Pneumotaxic centre in the pons, which moderates the activity of the respiratory rhythm centre to regulate the breathing rate and pattern.
  • Chemosensitive area adjacent to the respiratory rhythm centre in the medulla, which detects the levels of carbon dioxide and hydrogen ions in the blood and cerebrospinal fluid.
  • Receptors associated with the aortic arch and carotid artery (peripheral chemoreceptors), which detect changes in the partial pressure of oxygen (pO2) in the blood.

• Rationale: Although receptors in the aortic arch and carotid artery (peripheral chemoreceptors) are important, they are not sufficient on their own to regulate respiration. Central control mechanisms in the brain are also involved.

• Rationale: While this statement includes important components, it omits the critical roles of the respiratory rhythm centre in the medulla and the pneumotaxic centre in the pons, which are essential for the regulation of the rhythm and rate of breathing.

• The regulation of respiration is a complex process involving multiple centers in the brain and various peripheral receptors. These include the respiratory rhythm centre in the medulla, the pneumotaxic centre in the pons, chemosensitive areas in the medulla, and peripheral receptors in the aortic arch and carotid artery, all working together to ensure proper respiratory function.

The correct answer is Neural signals from the pneumatic centre of the pons increase the duration of inspiration.

Explanation:

• The pneumotaxic centre can moderate the functions of the respiratory rhythm centre.
• Neural signal from this centre can reduce the duration of inspiration and thereby alter the respiratory rate.
• About 90% of the carbon dioxide is carried as bicarbonate.
• Emphysema is the reduction in the surface area of alveoli and smoking leads to this condition.
• Receptors associated with aortic arch and carotid artery also can recognise changes in CO₂ and H⁺ concentration and send necessary signals to the rhythm centre for remedial actions.
• The role of oxygen in the regulation of respiratory rhythm is quite insignificant.

The Correct answer is Increased saliva and digestion.

Key Points

• Chewing food thoroughly stimulates the production of saliva, which contains enzymes like amylase and lipase that aid in the breakdown of carbohydrates and fats.
• Saliva not only helps in digestion but also moistens the food, forming a bolus, which makes it easier to swallow and pass through the esophagus.
• Proper chewing enhances the breakdown of food into smaller particles, which increases the surface area for digestive enzymes to act upon in the stomach and intestines, improving overall digestion.
• Mindful eating, which involves chewing thoroughly, allows the brain to register satiety signals, reducing the likelihood of overeating and supporting healthy weight management.
• Chewing thoroughly reduces the risk of indigestion and bloating as it ensures food is adequately processed before it reaches the stomach.
• It promotes better absorption of nutrients by ensuring the food is broken down effectively, facilitating easier digestion and assimilation in the small intestine.
• Chewing stimulates the production of gastric juices in the stomach, further aiding the digestive process.
• Mindful eating and thorough chewing can also enhance the sensory experience of eating, allowing individuals to savor flavors, textures, and aromas more deeply.

Additional Information

• Faster eating
  • Faster eating often leads to overeating because the brain does not have enough time to process satiety signals, resulting in delayed recognition of fullness.
  • It can cause digestive issues like bloating, gas, and indigestion because food is not adequately chewed.
• Increased calorie intake
  • Chewing food thoroughly during mindful eating generally helps reduce calorie intake as it promotes a sense of fullness, contrary to this option.
  • Increased calorie intake is often associated with unmindful or rushed eating practices.
• Reduced nutrient absorption
  • Chewing food thoroughly actually enhances nutrient absorption because it facilitates better digestion and breakdown of food particles.
  • Reduced nutrient absorption can occur if food is swallowed without proper chewing, leading to incomplete digestion.

The correct answer is A-IV, B-II, C-I, D-III

Explanation:

A. Progesterone - IV (Corpus luteum):

• Progesterone is a steroid hormone primarily produced by the corpus luteum in the ovaries.
• It plays a critical role in regulating the menstrual cycle and maintaining pregnancy by preparing the uterine lining for implantation of the fertilized egg.
• During pregnancy, the placenta also produces progesterone to support fetal development.

B. Relaxin - II (Ovary):

• Relaxin is a hormone secreted mainly by the ovary, specifically by the corpus luteum, during pregnancy.
• It helps relax the ligaments in the pelvis and softens the cervix to prepare for childbirth.
• It also plays a role in inhibiting uterine contractions during early pregnancy.

C. Melanocyte-Stimulating Hormone (MSH) - I (Pars intermedia):

• MSH is produced by the pars intermedia of the pituitary gland (a part of the intermediate lobe of the pituitary).
• It regulates the production and release of melanin in the skin, which affects pigmentation.

D. Catecholamines - III (Adrenal Medulla):

• Catecholamines such as adrenaline (epinephrine) and noradrenaline (norepinephrine) are produced by the adrenal medulla.
• These hormones are part of the body's response to stress ("fight-or-flight" response), increasing heart rate, blood pressure, and glucose levels.
• Catecholamines also stimulate the breakdown of glycogen resulting in an increased concentration of glucose in blood. In addition, they also stimulate the breakdown of lipids and proteins.

The correct answer is the Pivotal joint.

The joint where our neck joins the head is a pivotal joint. It allows us to bend our head forward and backwards and turn the head to our right or left. In a pivotal joint, a cylindrical bone rotates in a ring.
Additional Information

•  The ball and socket joint provides swinging and rotating movements.
  • The articulating bone is received into the cavity of another bone, allowing the distal bone to move around three main axes with a common centre.
  • The joint has to stabilize ligaments that limit the directions and extent to which the bones can be moved
• Hinge joints are those that allow movement along one plane.
  • They facilitate bending and straightening actions, such as flexing a finger.
  • In a hinge joint, protective cartilage covers the bones, and a thick gel called synovial fluid lubricates them, allowing them to move without rubbing against one another.

The correct answer is The iris contracts the pupil to allow less light to enter the eye.Key Points

• When we move from a brightly lit room to a dimly lit room, our eyes take some time to adjust to the change in lighting.
• This is because the iris, which controls the amount of light entering the eye, needs to adjust to the new lighting conditions.
• This helps to improve the clarity of the image that is formed on the retina.
• Dilation of the eye lens actually allows more light to enter the eye, and so this would not help in a dimly lit room.​

Additional Information

• Iris:
  • The iris is a circular muscle in the eye that controls the size of the pupil and the amount of light entering the eye.
  • It is responsible for adjusting the amount of light that enters the eye based on the lighting conditions.
• Pupil:
  • ​The pupil is the black circular opening in the center of the iris that allows light to enter the eye.
  • Its size is controlled by the iris, which adjusts it based on the amount of light available.
• Vitreous humour:
  • The vitreous humour is a gel-like substance that fills the eye and helps to maintain its shape.
  • It does not have any control over the amount of light entering the eye.
• Cornea:
  • The cornea is a transparent layer at the front of the eye that helps to focus light onto the retina.
  • It does not have any control over the amount of light entering the eye.

Concept:

• The brain is a complex and vital organ in an animal's body that controls several activities.
• Memory, motor skills, breathing, vision, hunger, libido, etc. are some of the various processes in an animal's body that are regulated by the brain.
• The brain along with the spinal cord forms the Central Nervous System.
• A brain is made up of fats, carbohydrates, water, protein and salts.
• It comprises blood vessels and nerves.
• The brain carries out several functions of the body by sending and receiving chemical and electrical signals throughout the body.
• The brain is divided into three parts:
  • Forebrain (Prosencephalon)
  • Midbrain (Mesencephalon)
  • Hindbrain (Rhombencephalon)

Explanation:

• Option 1: Medulla oblongata - INCORRECT​
  • The medulla oblongata is located in the hindbrain. 
  • It is located at a point where the brain and spinal cord connect.
  • Functions:
  1. Controls heartbeats
  2. Controls breathing as well as blood pressure
  3. Produces reflective actions such as sneezing, coughing, vomiting, etc.
• Option 2: Midbrain - INCORRECT
  • ​Midbrain comprises two parts - Tectum and Tegmentum.
  • Midbrain consists of neuron clusters that facilitate various functions.
  • Functions:
  1. Facilitates visual reflexes
  2. Hearing
  3. Determines movements concerning responses and changes in the environment.
• Option 3: Cerebrum - INCORRECT
  • Cerebrum is the largest part of the brain.
  • It is part of the forebrain that is further divided into Frontal lobe, Parietal lobe, Occipital lobe and Temporal lobe.
  • Functions:
  1. Regulates temperature
  2. Enables speech
  3. Involved in thinking, reasoning and problem-solving
  4. Co-ordinates movements
  5. Controls emotions and learning, etc.
• Option 4: Cerebellum - CORRECT
  • The cerebellum is also known as the little brain.
  • The cerebellum is located in the hindbrain above the brainstem.  
  • Functions:
  1. Controls voluntary muscular movement like walking, posture, etc.
  2. Responsible for the maintenance of posture, balance and equilibrium.

So the correct answer is option 4 (Cerebellum).

Key Points

• The Duramater is the tough and outermost layer of the meninges that covers the brain and spinal cord.
  • It is a thick and fibrous layer that protects the brain and spinal cord from external shocks or trauma.

Additional Information

• Piamater plays a crucial role in protecting and nourishing the brain.
  • The Piamater is the thin, delicate, and innermost layer that covers the surface of the brain and spinal cord.
• The Arachnoid is the middle layer of the meninges that covers the brain and spinal cord.
  • It is a delicate and web-like layer that is located between the Duramater and the Piamater.
  • The Arachnoid is filled with cerebrospinal fluid (CSF), which helps to cushion the brain and spinal cord.
• The Coracoid is a bone in the shoulder that connects the scapula and the clavicle. It has no relation to the brain or its coverings.

Correct answer: 1)

Concept:

• The respiratory system consists of organs and different structures that help in the exchange of gases in both plants and animals.
• The human respiratory system consists of the nose (nasal cavity), pharynx, larynx, trachea, bronchi, bronchioles, lungs, and alveoli.

Explanation:

• The respiratory system is divided into conducting zone and a respiratory zone.
• Conducting zone starts from the nose and ends in the bronchioles.
• The respiratory zone includes terminal bronchioles and alveoli.
• The conduction zone has different functions such as, it clears the inhaled air from foreign particles, humidifying the inhaled air, and also bringing the temperature of the inhaled air to body temperature.
• The respiratory zone is the site for an exchange of gases such as oxygen and carbon dioxide.

So, the correct answer is option 1

The correct answer is Acromegaly - Adrenaline. Key Points

• Acromegaly is a hormonal disorder that results in the excessive production of growth hormone, which is produced by the pituitary gland.
• Adrenaline is not associated with acromegaly.
• Instead, it is a hormone that is produced by the adrenal glands and is involved in the body's "fight or flight" response.
• Cushing's syndrome is a condition that is caused by the overproduction of cortisol, a steroid hormone that is produced by the adrenal glands.
• Diabetes is a condition that is characterized by high levels of glucose (sugar) in the blood.
  • It is caused by a lack of insulin, a hormone that is produced by the pancreas.
• Thyroxin, which is associated with goitre, is involved in regulating metabolism and growth.
  • It helps to regulate the body's energy production and influences the development of the brain, bones, and muscles.

Additional Information

• Cortisol, which is associated with Cushing's syndrome, is involved in regulating a variety of bodily functions, including metabolism, immune response, and stress response.
• Insulin, which is associated with diabetes, regulates the levels of glucose (sugar) in the blood.
  • It allows cells to use glucose for energy and helps to store excess glucose in the liver and muscles.
• Goitre is a condition that is characterized by an enlarged thyroid gland.
  • It is often caused by a deficiency of iodine, which is necessary for the production of thyroid hormones.

Concept:

• Exocrine glands: The glands which secrete substances on the epithelial surface through the ducts are called exocrine glands. Eg. sweat, salivary, mammary, ceruminous, lacrimal, sebaceous, prostate, and mucous glands.
• Endocrine glands: The glands which secrete hormones and other substances directly into the bloodstream are called endocrine glands. Eg. Pituitary, Pineal, Thyroid, Thymus, Gonads, etc.

​Explanation:

Endocrine Glands: 

• Endocrine glands lack ducts and are hence, called ductless glands. Their secretions are called hormones
• Hormones are non-nutrient chemicals that act as intercellular messengers and are produced in trace amounts
• The hormones are emptied directly into the bloodstream and then transported to target cells by blood
• The endocrine system regulates the metabolic activities of the body like body growth, sexual development & other biological processes
• The endocrine gland signalling is slow but its effects are prolonged 
• Some of the major endocrine glands are the Pituitary, Pineal, Thyroid, Thymus, Gonads, etc.

 Additional Information

The correct answer is O^-

Explanation:

• The O-ve negative is the universal donor blood group.
• It has a low risk of causing transfusion reactions.
• O-ve is given in the case of emergency if the blood group is not known.
• Red blood cells have antigens on the surface and antibodies in the plasma.
• It has four major types of antigens.
  • Type A: It has A antigens on the surface of the red blood cells and anti-B antibodies in the plasma.
  • Type B: It has B antigens on the surface of the red blood cells and anti-A antibodies in the plasma.
  • Type AB: It has both A and B antigens on the surface of the red blood cells and no antibodies in the plasma.
  • Type O: It has no antigens, but both anti-A and anti-B antibodies in the plasma.

Each group can be either RhD +ve or RhD -ve.

The correct answer is Deficiency of protein.

Key Points

• About Proteins:
  • Proteins are one of the building blocks of body tissue.
  • Proteins are made up of Carbon, Hydrogen, Oxygen, and Nitrogen.
  • Proteins help for the growth and repair of the body.
  • Proteins are the nutrient known as 'bodybuilders'.
  • Amino acid is the basic unit of proteins.
  • The Soyabean contains the highest percentage of protein.
  • The major source of proteins is meat, milk, egg, fish, gram, etc.
• Marasmus is also caused by severe protein deficiency.
• Kwashiorkor is caused by severe protein deficiency.​

Additional Information

• Deficiency of iron
  • Iron deficiency can lead to Anaemia.
  • Iron deficiency anemia is a common type of anemia — a condition in which blood lacks adequate healthy red blood cells.
  • Red blood cells carry oxygen to the body's tissues. 
  • This means that red blood cells aren’t going to be able to carry as much oxygen to your tissues.​
• Calcium deficiency occurs at any stage.
  • It can result in rickets, osteoporosis, and osteopenia.
  • Osteoporosis occurs at later stages of life and is a disease in which bone becomes more fragile and more likely leading to fractures.

• Deficiency of vitamin A
  • Severe vitamin A deficiency can lead to night blindness and poor vision. 
  • People with night blindness do not see well in the dark, But they can see normally if enough light is present.
  • Vitamin A is found in many foods like leafy green vegetables, orange vegetables (carrots, sweet potatoes, pumpkin), eggs, and cantaloupes.

The correct answer is Arteries.Key Points

• Arteries are thick-walled blood vessels that carry oxygenated blood away from the heart to various organs of the body.
• They have a muscular wall that contracts and relaxes to regulate blood pressure and flow.
• Arteries also branch out into smaller vessels called arterioles, which further divide into capillaries where exchange of nutrients and waste products takes place.
• Veins, on the other hand, carry deoxygenated blood back to the heart from various organs of the body.
• Tracheas are part of the respiratory system and carry air to and from the lungs.

Additional Information

• Veins:
  • These are thin-walled blood vessels that have valves to prevent backflow of blood.
  • They are located closer to the surface of the skin and are often visible as blue or greenish lines.
• Plasma:
  • This is the liquid component of blood that carries nutrients, hormones, and waste products.
  • It also helps in maintaining the pH balance and temperature of the body.
  • Plasma is not a vessel but a component of blood.