TRANSPORT

• Plant transport


  Substance transport involves movement of water plus macronutrients and micronutrients through the cells and the vascular system. Water taken up by the roots has to reach all parts of the plant, usually up to the growing stem. The photosynthates or food synthesized by the leaves (source) also have to be moved to all parts including the sink such as root tips.
• Routes of Absorption of Water and Minerals across Plant roots

  • Symplast route - through plasmodesmata (cell junction that connects cytoplasm of adjacent plant cell)
  • Apoplast route - along all cell walls
• Long Distance Movement


  Xylem Transport - The movement is controlled by pressure potential (hydraulic pressure).
• Imagine this process similar to sucking water from a straw.
• How are water and minerals pulled through the xylem?

  Water is mainly pulled by transpiration from leaves. (Cohesion-tension-transpiration pull Model)
• Water Properties


  • Cohesion - the mutual attraction between water molecules
  • Adhesion - the attraction of water molecules to polar surfaces
  • Surface tension - the tendency to occupy the least possible surface area
• Tension


  The release of water from the leaves creates tension in the xylem sap, causing upward flow of water from the stems towards the leaves
• Transpiration


  Evaporation of water from stomata in leaves which pulls water and minerals up stems and provides evaporative cooling, but results in tremendous loss of water, which must be controlled.
• Guttation


  With high humidity and wet soils some plants will even have water pushed out of the leaves
• Phloem Transport


  It functions for translocation, the transport of food nutrients such as glucose and amino acids from the leaves (source) to all other cells (sink) of the plant. Since the source to sink relationship is variable, the direction of movement in the phloem can be upwards or downwards, bi-directional. Unlike the one-way flow of water in transpiration, food in phloem sap can be transported in any required direction so long as there is a source of sugar and a sink able to use, store or remove the sugar
• Functions of the Circulatory System

  • Transport of nutrients and respiratory gases to every part of the body
  • Collection of waste products of metabolism and excess substances bringing them to organs for their proper elimination
  • Protection against diseases by way of phagocytosis and antibody production of the blood cells
• Types of Circulatory System

  • Open circulatory system - blood does not stay in the blood vessel, poured directly into the body tissues
  • Closed circulatory system - blood passes via the blood vessels; it does not come in direct contact with the body tissues
• General Components of the Circulatory System

  • Blood - the circulating fluid
  • Heart - a pumping organ that circulates blood through the body
  • Blood vessels - tubes through which the blood can circulate through out the body
• Functions of the Circulatory System

  • Transporting substances around the body. These include oxygen, glucose, carbon dioxide, nutrients, water and waste products.
  • Protecting the body. Blood contains cells and anti-bodies that fight infection and clotting agents to stop bleeding.
  • Controlling body temperature.
• Vascular tissue (Blood)


  Specialized form of connective tissue
• Components of Blood


  • Blood cells
  • Plasma (extracellular matrix)
• What's in Blood?


  • Red blood cells
  • White blood cells
  • Platelets
  • Plasma
  • Carbon dioxide
  • Digested food
  • Waste (urea)
  • Hormones
  • Oxygen
• Blood


  The body's means of transporting substances around. It transports oxygen from the lungs to the heart and then to the body's tissues, carbon dioxide from the tissues to the heart and then to the lungs to be expired, materials like hormones from one organ to another, nutrients (especially glucose) and minerals from the intestines to the tissues, and waste products to the kidneys.
• Red blood cells


  Also called erythrocytes. Disc-shaped. Made in the bone marrow. Contain a red-colored compound called hemoglobin which bonds with oxygen to form oxyhemoglobin. Transport oxygen to the tissues.
• Red Blood Cells


  • Contain hemoglobin, a molecule specially designed to hold oxygen and carry it to cells that need it.
  • Can change shape to an amazing extent, without breaking, as it squeezes single file through the capillaries.
  • A biconcave disc that is round and flat without a nucleus
• Erythrocytes (RBCs)


  Small, biconcave discs. Transport oxygen and CO2, cytoplasm is full of hemoglobin molecules. Have no nuclei or organelles. Pick up O2 at lung capillaries and release it at body tissue capillaries. Survive for ~100-120 days in the circulation. Worn out RBCs are removed by macrophages of the spleen and liver.
• White blood cells


  Also called leucocytes. They are bigger than red blood cells and have large nuclei. Act as the body's defense system. Some white blood cells surround and consume harmful microbes. Some produce antibodies that fight infection.
• Types of White Blood Cells

  • Lymphocytes
  • Macrophages
• Lymphocytes


  Some fight disease by making antibodies to destroy invaders by dissolving them. Other lymphocytes make antitoxins to break down poisons.
• Macrophages


  Eat and digest micro-organisms.
• Leukocytes (WBCs)


  • Granulocytes - Neutrophils, Eosinophils, Basophils
  • Agranulocytes - Lymphocytes, Monocytes
• Leukocytes (6-10,000 per µL)

  • Granulocytes (polymorphonuclear leukocytes) - Neutrophils 60-70%, Eosinophils 2-4%, Basophils 0.5-1%
  • Agranulocytes (mononuclear leukocytes) - Lymphocytes 20-30%, Monocytes 3-8%
• Platelets


  Formed in red bone marrow. Produce thrombokinase – a chemical needed for blood clotting. Platelets help to repair tissues and close wounds both internally and externally. When needed, they grow into irregular shapes and stick together to form a plug over the wound.
• Thrombocytes (Platelets)


  Disc-shaped, plasma membrane enclosed fragments of cytoplasm. Broken off from larger cells called megakaryocytes. Aids in clotting. Release secretory granules that help recruit other platelets.
• Blood Clotting


  Platelets aggregate at the site of a wound. Broken cells and platelets release chemicals to stimulate thrombin production. Thrombin converts the protein fibrinogen into sticky fibrin, which binds the clot.
• Components of Plasma


  • Water (~90%)
  • Nutrients
  • Waste products (CO2, ammonia, urea)
  • Hormones
  • Oxygen
  • Proteins including fibrinogen, a clotting factor
• Serum


  Everything in plasma, minus the clotting factors
• Bone Marrow and Hematopoiesis

  Red bone marrow actively generates blood cells. In adults, found only in vertebrae and girdles, and in the proximal epiphysis of the humerus and femur. Yellow marrow is dormant; only makes blood cells in emergencies.
• Hemophila


  A well-known blood-clotting disorder. Absence of a particular clotting factor.
• Hematopoietic cells


  Adult stem cells that become the various types of blood cells, located in the bone marrow.
• Agglutination


  Clumping of red blood cells can cause blood to stop circulating in small blood vessels, leading to organ damage. This is followed by hemolysis (bursting of RBC), which if extensive, can cause the death of the individual.