Tag: science & technology

The lung is part of the respiratory system, exchanging oxygen and carbon dioxide. The circulatory system comprises the heart, blood vessels (arteries, veins, capillaries), and blood - which transport materials throughout the body. Lungs and heart work together but belong to different systems.

The small intestine (duodenum, jejunum, ileum) is the longest digestive tube section at about 6 meters (20 feet). Most nutrient absorption occurs here through villi and microvilli. The large intestine is about 1.5 meters, and the stomach is a J-shaped organ, not a tube.

The liver is the body's largest internal gland (1.4-1.6 kg), performing vital functions: bile production, detoxification, protein synthesis, glycogen storage. The thyroid and pituitary are much smaller endocrine glands. Kidneys filter blood but are excretory organs, not glands.

Epithelial tissue forms protective covering layers on body surfaces (skin epidermis), lines internal cavities and organs, and comprises glands. Cells are tightly packed with minimal extracellular matrix. Connective tissue binds structures, nervous tissue transmits signals, and muscle tissue contracts.

The sinoatrial (SA) node, located in the right atrium near the superior vena cava, is the heart's natural pacemaker. It spontaneously generates electrical impulses (~60-100 bpm) that initiate each heartbeat. The AV node delays impulses, and Purkinje fibers conduct signals to ventricles.

The hindbrain (rhombencephalon) comprises the cerebellum, pons, and medulla oblongata. The mesencephalon is the midbrain, and prosencephalon is the forebrain (cerebrum + diencephalon). These are developmental divisions of the brain.

Aqua fortis is Latin for 'strong water' and historically refers to nitric acid (HNO₃). Nitric acid is a strong corrosive acid, while nitrous oxide (N₂O) is a gas, and nitrogen (N₂) is an element.

Arboreal creatures are tree-dwelling animals. The term comes from the Latin 'arbor' meaning tree. Mountains, hills, and rivers are not the primary habitat of arboreal animals - they live in and among trees.

The mandible is the anatomical name for the lower jawbone in vertebrates. The occipital bone is at the back of the skull, and the cranium refers to the entire skull enclosing the brain.

Ruminating refers to the process of chewing cud - regurgitated food that ruminants like cows, sheep, and deer chew again to aid digestion. It's a multi-stage digestive process, not related to roaming or sleeping.