Tag: science & technology

The tibia, also called the shinbone, is the larger and stronger of the two bones in the lower leg (the other being the fibula). It connects the knee to the ankle and bears most of the body's weight.

Hemoglobin contains iron ions (Fe²⁺) in its heme groups, which bind to oxygen molecules in the lungs and release them in tissues. Each hemoglobin molecule can carry up to 4 oxygen molecules thanks to its 4 iron-containing heme groups.

Red blood cells (erythrocytes) are produced in the bone marrow through a process called erythropoiesis. In adults, this primarily occurs in the vertebrae, sternum, ribs, and pelvis. The liver produces RBCs only during fetal development.

The cerebrum is the largest part of the human brain, making up about 85% of its weight. It's responsible for higher functions like thought, memory, reasoning, and voluntary movement. The cerebellum coordinates movement, while the medulla controls vital functions like breathing and heart rate.

Calcium phosphate (specifically hydroxyapatite) is the primary mineral component of bones and teeth, providing hardness and strength. Bones are about 60-70% mineral (mostly calcium phosphate) and 30-40% organic matrix (mostly collagen).

The lacrimal glands, located above each eye, secrete tears to lubricate and protect the eyes. Tears contain water, electrolytes, antibodies, and enzymes that maintain eye health and wash away irritants.

The liver is the largest internal gland and organ in the human body (weighing about 1.5 kg). It performs over 500 functions including detoxification, bile production, metabolism of nutrients, and synthesis of plasma proteins.

Short-sightedness (myopia) occurs when the eyeball is too long or the lens is too strong, causing light to focus in front of the retina. A concave lens diverges incoming light before it enters the eye, moving the focal point back onto the retina for clear vision.

Typhoid (caused by Salmonella typhi) and cholera (caused by Vibrio cholerae) are classic water-borne diseases. They spread through contaminated water or food washed with contaminated water, not through air or direct contact.

Pyorrhea, also known as periodontitis, is an inflammatory disease affecting the tissues surrounding the teeth, primarily the gums. It causes gum infection, inflammation, and can lead to tooth loss if untreated. The other options (nose, heart, lungs) are unrelated to this condition.