Internal Structures of Organisms

External and Internal Structures of Organisms

• External structures are the outer parts of an organism, such as roots, stems, leaves, and flowers in plants, and body, arms, legs, and head in animals.
• Internal structures are the inner pieces and parts that keep organisms alive, help them grow, and help them reproduce.

Internal Structures of Animals

• The heart is a vital internal structure that pumps blood through the body's blood vessels.
• Blood vessels are like highways that transport essential chemicals, including nutrients, gases, and hormones, to every part of the body.
• The stomach breaks down food into nutrients, which are then absorbed into the blood.
• Lungs are responsible for breathing, taking in oxygen, and releasing carbon dioxide.
• The brain processes sensory information and controls the body's functions.

Internal Structures of Plants

• Xylem is a transportation system that carries water and minerals from the roots to the leaves.
• Phloem carries substances downward, moving sugar from the leaves to the roots.
• Chloroplasts in plant leaves can convert water, carbon dioxide, and light into sugar and oxygen through photosynthesis.
• Xylem and phloem work together to transport essential substances throughout the plant.

Learn about the inner pieces and parts of plants and animals that keep them alive, help them grow, and help them reproduce. Explore the basic internal structures of organisms.