LESSON 6

• Both plants and animals require a circulatory system to transport essential substances throughout their bodies.
• Plants have a unique circulatory system known as the vascular system.
• Xylem is responsible for the transport of water and minerals from the roots to the rest of the plant
• Xylem is composed of specialized cells called tracheids and vessel elements.
• tracheids and vessel elements. - These cells are interconnected, forming long tubes that allow for the upward movement of water through capillary action.
• Xylem also provides structural support to the plant.
• Phloem is responsible for the transport of organic compounds, such as sugars, from the leaves to other parts of the plant.
• phloem consists of sieve tube elements and companion cells.
• Sieve tube elements - form long tubes that allow for the movement of sugars through pressure flow.
• Companion cells- provide metabolic support to the sieve tube elements
• Animals have a closed circulatory system, which consists of a heart, blood vessels, and blood
• Heart - The heart is a muscular organ that pumps blood throughout the body.
• Heart consists of four chambers: two atria and two ventricles.
• The atria receive blood from the body and lungs, while the ventricles pump blood out to the body and lungs.
• Blood Vessels - are responsible for carrying blood to and from the heart and various organs
• Arteries carry oxygenated blood away from the heart
• veins carry deoxygenated blood back to the heart
• Capillaries are tiny, thin-walled vessels that allow for the exchange of nutrients, gases, and waste products between the blood and body tissues.
• Blood - is a fluid connective tissue that carries oxygen, nutrients, hormones, and waste products throughout the body.
• Transpiration - Water is absorbed by the roots and transported through the xylem to the leaves, It then evaporates from the leaf surface through small openings called stomata.
• transpiration- creates a suction force that pulls water up through the xylem.
• Translocation - Sugars produced in the leaves through photosynthesis are transported through the phloem to other parts of the plant.
• translocation- occurs through pressure flow, where sugars move from areas of high concentration to areas of low concentration
• Heart Pumping - The heart contracts and relaxes rhythmically, pumping blood throughout the body
• pumping action ensures the circulation of oxygen, nutrients, and hormones to all cells and organs.
• Blood Vessel Network - Blood vessels form an extensive network that allows for the distribution of blood to different parts of the body.
• Capillaries facilitate the exchange of substances between the blood and body tissues