A spiral shape or structure, often used to describe the shape of DNA or other biomolecules.

An infection caused by parasitic worms (helminths), such as roundworms or flatworms.

A type of T lymphocyte that assists in immune responses by activating other immune cells, such as B cells and cytotoxic T cells.

A bony structure in vertebrates that encases blood vessels, particularly in the region of the tail in fish.

A rare and aggressive cancer that originates in the blood vessels, commonly affecting the spleen, liver, and heart.

The accumulation of menstrual blood in the vagina, typically due to an obstruction in the vaginal opening.

Organisms that feed on blood, such as mosquitoes, leeches, and some species of bats.

The process of blood cell formation, including the production of red blood cells, white blood cells, and platelets.

The iron-containing molecule in hemoglobin that binds oxygen, allowing the transport of oxygen in the blood.

A group of polysaccharides found in plant cell walls, which are less rigid than cellulose and can be broken down by certain enzymes.