Which node is called the natural pacemaker of the heart?
The SA node located in the right atrium initiates the electrical impulse that triggers each heartbeat. It is called the natural pacemaker of the heart.
Question 2 of 20
The functional unit of the kidney is called the:
The nephron is the structural and functional unit of the kidney. Each kidney contains approximately 1 million nephrons.
Question 3 of 20
Gas exchange in the lungs takes place at the:
Alveoli are tiny air sacs at the end of bronchioles. Their thin walls make them the site of oxygen-CO2 exchange.
Question 4 of 20
Which is the largest gland in the human body?
The liver is the largest gland and largest internal organ in the human body.
Question 5 of 20
Which is the smallest bone in the human body?
The stapes in the middle ear is the smallest bone, measuring only about 3mm.
Question 6 of 20
The pituitary gland is called the "master gland" because it:
The pituitary gland secretes tropic hormones that regulate other endocrine glands including thyroid, adrenal and gonads.
Question 7 of 20
Insulin hormone is secreted by which cells of the pancreas?
Beta cells of the Islets of Langerhans secrete insulin. Alpha cells secrete glucagon.
Question 8 of 20
A reflex arc involves which part of the nervous system as its centre?
A spinal reflex arc uses the spinal cord as the integration centre, allowing rapid automatic responses without involving the brain.
Question 9 of 20
Which enzyme begins starch digestion in the mouth?
Salivary amylase converts starch into maltose in the mouth. Digestion of starch begins in the mouth, not the stomach.
Question 10 of 20
The human heart is enclosed in a membrane called the:
The pericardium is the double-walled sac surrounding the heart. Pleura covers lungs; meninges protect the brain.
Question 11 of 20
Which blood group is known as the "universal donor"?
O negative is the universal donor because red blood cells lack A, B, and Rh antigens. AB+ is the universal recipient.
Question 12 of 20
The largest part of the human brain is the:
The cerebrum is the largest part of the brain, comprising about 85% of brain mass. It controls intelligence, memory and voluntary movements.
Question 13 of 20
Which part of the eye is responsible for focusing light on the retina?
The lens focuses light on the retina by changing shape (accommodation). The iris controls pupil size.
Question 14 of 20
Ultrafiltration of blood occurs in which part of the nephron?
Ultrafiltration occurs at the glomerulus inside Bowman capsule. Blood pressure forces water, glucose, urea and salts into the capsule.
Question 15 of 20
Which hormone regulates blood calcium levels?
PTH from parathyroid glands raises blood calcium. Calcitonin from thyroid lowers it.
Question 16 of 20
The normal human body temperature is approximately:
Normal body temperature is 37 degrees C or 98.6 degrees F. The hypothalamus maintains this temperature.
Question 17 of 20
Which organ produces bile stored in the gallbladder?
Bile is produced by the liver and stored in the gallbladder. It emulsifies fats in the duodenum.
Question 18 of 20
Which vitamin is called the sunshine vitamin?
Vitamin D is synthesised in the skin by UV sunlight. It is essential for calcium absorption. Deficiency causes rickets in children.
Question 19 of 20
The longest bone in the human body is the:
The femur (thigh bone) is the longest and strongest bone. The stapes is the smallest.
Question 20 of 20
The fight-or-flight response is primarily triggered by which hormone?
Adrenaline from the adrenal medulla triggers fight-or-flight: increased heart rate, dilated pupils, raised blood sugar.