Module 3 - Transportation and Circulation & Gas Exchange

• In circulation, these are the needs to be transported:

  • nutrients from digestive system
  • gases coming from gas exchange system
  • waste products from cells
  • hormones needed for body regulation
  • components of blood that are need for blood clotting and immune defense
• Two types of Mechanisms

  • Open Circulatory System - not enclosed in the blood vessels but is pumped into a cavity called hemocoel. does not require much energy compared to closed system.
  • Closed Circulatory System - the blood is confined to vessels and is separate from interstitial fluid. The blood unidirectionally from the heart around the systemic circulatory route.
• Heart Chambers of Animals:

  • Fish has one
  • Amphibians and reptiles has 3
  • Birds and Mammals has 4
• Hemolymph - a fluid equivalent to blood in most invertebrates, is occupying the hemocoel.
• As the animal moves and the heart beats, hemolymph is pushed into organs through openings and pulled back through holes called ostia
• In vertebrae cardiovascular system, the heart is composed of atrium that received blood, and ventricle that pump blood out. In blood vessels; arteries that carry blood away from the heart (arterioles are smaller arteries), veins return the blood to heart (venules are smaller veins), and capillaries are the point of exchange of materials (capillary beds are networks of capillaries).
• Mammalian four chambered heart is consist of two thin-walled receiving chambers, atria, and two thick-walled pumping chambers, and ventricles. These ventricles pump almost in unison.
• Blood is a connective tissue composed of liquid extracellular matrix called blood plasma that dissolves and suspend various cells and cell fragments.
• Blood has three general functions:

  • Transportation - transports oxygen from the lungs to the cells of the body. carries nutrients from gastrointestinal tract to body cells and hormones from endocrine glands to other body cells. Blood transports heat and waste products to various organs for elimination .
  • Regulation - help maintain homeostasis of all body fluid, blood also helps regulate pH using buffers. adjust body temperature.
  • Protection - protects against excessive loss from the cardiovascular system after injury. Also, its white blood cells protect against diseases by carrying phagocytosis.
• Blood has two components

  • 45% formed elements (cells and cell fragments)
  • 55% blood plasma - watery extracellular matrix contains dissolved substances
• Cellular Elements

  • Erythrocytes (red blood cells) - transport oxygen
  • Leukocytes (white blood cells) - defense and immunity
  • Platelets - blood clotting
• Two types of blood circulation:

  • Pulmonary Circulation - happens in lungs which carries deoxygenated blood away from the right ventricle of the lungs, and returns oxygenated blood to the left atrium and ventricle of the heart.
  • Systematic Circulation - circuit carries oxygenated blood from the left ventricle, through the arteries, to the capillaries in the tissues of the body. From the tissue capillaries, the deoxygenated blood returns through a system of veins to the right atrium of the heart.
• When blood reaches the capillaries, that’s the time of exchanging materials across the capillary walls. These exchanges passive and active transport. Water and small solutes enter or exits the cell membrane by diffusion. This happen when bulk flow transport due to fluid pressure and the blood pressure within capillary pushes fluid and smaller solutes through the capillary wall entering the neighboring tissues.
• Simple diffusion - a process that requires no energy input
• If there are large molecules such as proteins in blood move into and out of the endothelial cells packaged within endocytosis and exocytosis. Water moves by osmosis.
• Plant has two transport systems:

  • Xylem - transports minerals from water and minerals from roots up to other parts of the plant. Transpiration is the main driver in xylem. It occurs because of the opening of stomata to allow gas exchange for photosynthesis.
  • Phloem - transports food or sugar between leaves and other parts of the plants. It is important because it is need for molecular and cellular activities. Translocation is the process of transporting substances in the phloem.
• Unicellular organisms - the gas exchange surface of unicellular is the cell surface membrane

  • Cell surface membrane - is thin ensuring rapid gas exchange and it is moist to allow gases to dissolve.
• Multicellular Organism

  Direct Diffusion - facilitated the gas change across surface membranes and their cells must keep moist.
• Multicellular Organism

  The Body Surface

  • Flatworms and annelids use their outer surfaces as gas exchange surfaces. Gas exchange occurs at capillaries located throughout the body as well as those in the respiratory surface.
• Multicellular Organism

  Gills

  • are convoluted outgrowths containing blood vessels covered by a thin epithelial layer. Typically gills are organized into a series of plates and may be internal (as in crabs and fish) or external to the body (as in some amphibians).
  • are very efficient at removing oxygen from water: there is only 1/20 the amount of oxygen present in water as in the same volume of air
• Tracheal Systems

  • Tracheae are these tubes that carry air directly to cells for gas exchange. Spiracles are openings at the body surface that lead to tracheae that branch into smaller tubes known as tracheoles.
• Lungs

  • are ingrowths of the body wall and connect to the outside by as series of tubes and small openings
• Human Respiratory System

  • Lungs are large, lobed, paired organs in the chest (also known as the thoracic cavity). Thin sheets of epithelium (pleura) separate the inside of the chest cavity from the outer surface of the lungs. The bottom of the thoracic cavity is formed by the diaphragm.
  • Bronchi are reinforced to prevent their collapse and are lined with ciliated epithelium and mucus-producing cells.
  • Bronchi branch into smaller and smaller tubes known as bronchioles.
  • Bronchioles terminate in grape-like sac clusters known as alveoli.
  • Alveoli are surrounded by a network of thinwalled capillaries
• Ventilation is the mechanics of breathing in and out.