Unit 3: transport sytems

• Purpose of transport systems

  To take materials into our tissues
• Types of transport systems

  • Passive Transport Systems
  • Active Transport Systems
• Passive Transport Systems

  • Rely on diffusion to get materials in and out of the body
  • Generally works well for small aquatic animals
• Passive Transport Systems

  • Cnidarians (jellyfish)
  • Take food & water into a hollow space inside of them
  • Food diffuses in along the concentration gradient (moves from high to low)
• Passive transport isn't very efficient. Tends to be used by sessile (non moving) animals
• Active Transport Systems

  • Expend energy to move substances where they're needed
• Types of Active Transport Systems

  • Open circulatory system
  • Closed circulatory system
• Open circulatory system

  • No blood vessels (arteries or veins)
  • Blood fills the spaces between organs
  • Blood sloshes around when the organism moves
  • Simple heart helps spray the blood around
  • Inefficient as cells don't always get the food/oxygen they need
• Closed circulatory system

  • Blood is contained in a system of blood vessels
  • Much more efficient but requires lots of energy
• Blood flow in closed circulatory system

  Heart -> Arteries -> Arterioles -> Capillaries -> Venules -> Veins -> Heart
• Arteries

  • Thick walled vessels that carry blood out of the heart
  • Under the highest pressure
  • Narrow down into arterioles which take blood into the capillaries
• Capillaries

  • Small (<1mm) with very thin walls
  • Allow materials to diffuse into the blood
  • Connect to every tissue in the body
  • Materials diffuse between the capillaries and the interstitial spaces (between the cells)
  • Easily broken and repaired
• Capillary beds

  • Large groups of capillaries where materials move between cells and the blood stream
• Veins

  • Have to withstand lower pressure so their walls are thinner
  • Contain one way valves to prevent backflow
• Arteriosclerosis is a condition characterized by a build up of plaque along the walls of the arteries, causing the artery walls to harden and become less flexible
• Blood pressure


  The pressure in which the blood is pumped, highest during systole and lowest during diastole
• Blood pressure measurement


  A ratio of systolic pressure to diastolic pressure, measured in millimeters of mercury (mmHg)
• Average male blood pressure is 120/80 mmHg
• Blood pressure is a way to measure health
• Circulatory system


  A group of organs that work together, including the heart, blood vessels, and lungs
• Organ


  Several different tissues linked together for a common purpose
• Tissue


  A group of similar cells, such as muscle tissue
• Lungs


  • Designed to get oxygen into the blood and carbon dioxide out
  • The larger an organism, the larger its lungs will be
• Oxygen entry into the body

  1. Enters through the trachea

  2. Splits into two bronchi

  3. Each bronchus splits into a lung

  4. Bronchi branch into smaller bronchioles

  5. Bronchioles lead to alveoli
• Alveoli


  Small sacs in the lungs where gases diffuse in and out of the blood, covered in capillaries
• The alveoli increase the surface area of the lungs
• Carbon dioxide transport


  1. CO2 in the blood is carried by bonding to H2O to form H2CO3

  2. H2CO3 is changed back to CO2 at the lungs where it is exhaled
• Blood


  Made from several types of cells carried in a clear liquid called plasma
• Platelets


  • Clot the blood, their use is controlled by several chemical reactions
• Red blood cells (erythrocytes)


  The most abundant cells in the blood, contain an iron based compound called hemoglobin that carries oxygen
• Carbon monoxide


  Has a higher affinity (attraction) to hemoglobin
• Anemia


  A condition characterized by a lack of iron in the blood, causing the person to feel weak due to a lack of oxygen
• White blood cells (leukocytes)


  Immune system cells, normally very low in the blood, formed in bone marrow (B-cells) and the thymus gland (T cells), able to move independently to hunt for pathogens
• Leukemia


  Cancer of the bone marrow, affects white blood cell production
• Antigens


  Specifically shaped proteins on the surface of cells, different for each individual
• First line of defense


  • Non-cellular (skin, body temp, natural microbes)
• Immune system response to pathogens


  1. B cells & T cells work together to kill it

  2. B cells produce antibodies that bind to antigens

  3. Helper T cells produce lymphokines that boost antibody production

  4. Killer T cells destroy infected body cells

  5. Macrophages destroy bound pathogens
• Memory cells


  • Reduce the time to create antibodies from 7-14 days to 2-3 days
• Vaccination


  Dead pathogens or their antigens are released into the body, producing antibodies and memory cells for a fast response if the live pathogen ever enters
• AIDS (Acquired Immune Deficiency Syndrome)


  Caused by HIV (Human Immunodeficiency Virus) which infects a type of T cell called a T4 cell, can lay dormant for up to 10 years before becoming active