All Free Veterinary Science MCQs with Answers

• A. Atrioventricular node
• B. Bundle of His
• C. Purkinje fibres
• D. Sinoatrial node

Explanation: The sinoatrial node normally generates the fastest spontaneous electrical impulses and initiates each heartbeat.

• A. Parathyroid hormone
• B. Calcitonin
• C. Insulin
• D. Aldosterone

Explanation: Parathyroid hormone raises blood calcium through effects on bone, kidneys and indirectly the intestine.

• A. Increase airway mucus production
• B. Reduce alveolar surface tension
• C. Stimulate red cell formation
• D. Increase pleural fluid volume

Explanation: Surfactant lowers alveolar surface tension and helps prevent alveolar collapse, especially during expiration.

• A. Soft palate
• B. Thyroid cartilage
• C. Epiglottis
• D. Vocal fold

Explanation: The epiglottis folds over the laryngeal entrance during swallowing and helps direct food toward the oesophagus.

• A. Secrete digestive enzymes
• B. Store urine temporarily
• C. Produce red blood cells
• D. Create a medullary osmotic gradient

Explanation: The loop of Henle establishes a medullary osmotic gradient that supports concentration of urine.

• A. Troponin
• B. Actin
• C. Myosin
• D. Titin

Explanation: Calcium binds to troponin, causing tropomyosin to move away from actin's binding sites.

• A. Large alveolar sacs
• B. Air sacs with parabronchi
• C. A muscular diaphragm
• D. A complete tracheal ring system

Explanation: Birds use air sacs as bellows to move air through rigid lungs containing parabronchi, allowing largely unidirectional airflow.

• A. Cranial mesenteric artery
• B. Caudal vena cava
• C. Hepatic portal vein
• D. Hepatic artery

Explanation: The hepatic portal vein collects blood from the stomach, intestines, spleen and pancreas and delivers it to the liver.

• A. Simple cuboidal epithelium
• B. Pseudostratified columnar epithelium
• C. Stratified squamous epithelium
• D. Simple squamous epithelium

Explanation: Alveoli are mainly lined by thin simple squamous cells called type I pneumocytes, which allow rapid diffusion of gases.

• A. Epididymis
• B. Efferent ductules
• C. Seminiferous tubules
• D. Ductus deferens

Explanation: Sperm are produced in the seminiferous tubules but gain progressive motility and undergo functional maturation while passing through the…

• A. Zona reticularis
• B. Zona glomerulosa
• C. Zona fasciculata
• D. Adrenal medulla

Explanation: The zona glomerulosa produces mineralocorticoids, mainly aldosterone, which promotes sodium retention and potassium excretion.

• A. Aldosterone
• B. Atrial natriuretic peptide
• C. Antidiuretic hormone
• D. Parathyroid hormone

Explanation: Antidiuretic hormone, also called vasopressin, inserts aquaporin-2 channels into collecting duct cells and increases water reabsorption.

• A. Dopamine
• B. Norepinephrine
• C. Serotonin
• D. Acetylcholine

Explanation: Somatic motor neurons release acetylcholine at the neuromuscular junction, where it binds nicotinic receptors on the skeletal muscle…

• A. Red bone marrow
• B. Yellow bone marrow
• C. Spleen
• D. Thymus

Explanation: Red bone marrow is the principal site where new red blood cells are produced in healthy adult mammals.

• A. The horse normally breathes through its mouth
• B. The horse is an obligate nasal breather
• C. The dog is an obligate nasal breather
• D. The horse has no nasal turbinate bones

Explanation: Healthy horses are obligate nasal breathers because the soft palate forms a functional seal that limits oral breathing.

• A. Production of testosterone
• B. Formation of seminal plasma
• C. Storage of mature sperm
• D. Secretion of gonadotropins

Explanation: The cauda epididymis serves mainly as a reservoir for mature sperm before ejaculation.

• A. It increases sweating across the skin
• B. It increases heat production by muscles
• C. It reduces blood flow to the tongue
• D. It increases evaporative cooling from airways

Explanation: Panting increases airflow over moist surfaces of the mouth and upper respiratory tract, causing evaporation that removes heat.

• A. Phrenic nerve
• B. Vagus nerve
• C. Intercostal nerve
• D. Sympathetic trunk

Explanation: The phrenic nerve carries the main motor fibers to the diaphragm and is essential for inspiration.

• A. Rumen
• B. Omasum
• C. Reticulum
• D. Abomasum

Explanation: The omasum has many leaves that provide a large surface for absorption of water, electrolytes, and volatile fatty acids.

• A. Tricuspid valve
• B. Pulmonary valve
• C. Mitral valve
• D. Aortic valve

Explanation: The mitral valve, also called the bicuspid valve, separates the left atrium from the left ventricle.