LESSON 6: PLANT TRANSPORT AND ANIMAL CIRCULATION

• Plant Transport

  The transportation of substances in plants, involving the absorption of water and minerals from the soil through the roots and the conduction of these substances to the leaves
• Plant structure

  • Plants have simpler structures than animals, with only two systems: the shoot and root systems
• Plant transport process

  1. Absorption of water through the roots

  2. Up and down movement of substances in phloem
• Phloem transport

  1. Phloem cells conduct substances such as products of photosynthesis, water, and other compounds up and down the plant body

  2. Phloem tissues are adjacent to companion cells that give them support and nourishment
• Ascent of xylem sap


  1. Explained as a "push" from below by the water molecules gushing upwards through xylem vessels

  2. Can also be described as "pull" from above by a combination of transpiration and cohesion of water molecules through hydrogen bonds
• Pressure flow or bulk flow

  1. Maintains that in the plant there is a source cell and a sink cell

  2. Sink cells are growing parts of plants buds, flowers, fruits or even root tips

  3. Phloem tissues carry materials down and up
• Xylem lies adjacent to phloem tissues and water may easily diffuse from xylem to phloem
• Materials transported up and down the plant body by a combination of actions of phloem and xylem cells
• Animal Circulation

  The movement of blood through a complex network of vessels, transporting oxygen, nutrients, hormones, and waste products to and from cells
• Not all animals have a circulatory system, including the least complex forms of animals such as sponges, cnidarians, and flatworms
• Vertebrate circulatory system

  Consists of the heart, blood, and blood vessels
• Open circulatory system

  • Blood bathes the organs directly in a fluid called hemolymph
  • Hemolymph is pumped by a simple heart-like structure, circulating freely throughout the body cavity
  • Less efficient in terms of nutrient delivery and waste removal compared to closed systems, but still facilitates essential physiological functions
• Closed circulatory system

  • Predominantly found in vertebrate animals, including humans
  • Blood flows through a network of vessels, including arteries, veins, and capillaries, enclosed within the body
  • The blood remains distinct from interstitial fluid, and it is propelled by a muscular heart that pumps it through the vessels
• Cardiovascular system


  The system that includes the heart and a system of vessels called arteries, veins, and capillaries
• Purpose of the cardiovascular system

  Pumps blood around a closed circuit of vessels again and again through the various "circulations" of the body, maintaining homeostasis
• Heart


  • The vital organ that serves as the central component of the circulatory system, responsible for pumping blood throughout the body
• Blood flow through the heart

  1. The right atrium receives oxygen-poor blood from the body and pumps it to the right ventricle

  2. The right ventricle pumps the oxygen-poor blood to the lungs

  3. The left atrium receives oxygen-rich blood from the lungs and pumps it to the left ventricle

  4. The left ventricle pumps the oxygen-rich blood to the body
• Blood vessels

  • Arteries carry oxygenated blood away from the heart to the body's tissues
  • Veins carry deoxygenated blood back to the heart
  • Capillaries are the smallest blood vessels, allowing for the exchange of oxygen, nutrients, and waste products between the blood and the body's cells
• Blood

  The fluid that carries oxygen, nutrients, hormones, and other essential substances to the body's cells
• Blood components

  • Erythrocytes (red blood cells) - carry oxygen from the lungs and deliver it throughout the body
  • Thrombocytes (platelets) - form clots and prevent and stop bleeding
  • Leukocytes (white blood cells) - help defend the body against infection
• Blood flow

  The movement of blood through the vessels from arteries to the capillaries and then into the veins
• The cardiovascular system is essential for sustaining life by transporting oxygen, nutrients, and hormones to cells while removing waste products
• The cardiovascular system regulates body temperature, pH balance, and immune responses, ensuring proper function of tissues and organs
• The cardiovascular system is the body's lifeline, providing the necessary support for all physiological processes to occur efficiently and effectively