Genetic variation is stored in a populationâs gene poolâthe combined. alleles of all of the individuals in a population. Different combinations of. alleles in a gene pool can be formed when organisms mate and have offspring. Each allele exists at a certain rate, or frequency.
Also found in: Wikipedia. cosÂ·tal surÂ·face. the surface of certain structures that face the ribs; they are the costal surfaces of the lungs (facies costalis pulmonis [TA]) and the scapula (facies costalis scapulae [TA]).
SURFACE ANATOMY AND FEATURES OF THE. HEART AND THE PERICARDIUM. THE PERICARDIUM: DEFINITION / DESCRIPTION (Fig 1): The pericardium is a double-walled, truncated, cone-shaped fibroserous sac, which encloses the. heart within the middle mediastinum. Its main function is to prevent sudden overfilling of the heart. It also secretes serous fluid, which prevents friction between its inner surface and the outer surface.