circulatory and respiratory

• We breathe for GAS exchange (O2 in, CO2 out)

  for cellular respiration (making energy)!
• •Respiratory systems allow animals to move O2 (needed for cellular respiration) into body tissues and remove CO2 (waste product of cellular respiration) from cells.
• Some animals have gas exchange in their skin, they have low metalbolic rates and are aquatic
• Gills(aquatic), spiracles(terrestrial), lungs(most terrestrial vertebrates), these all help gas exchange
• Fish gills use a countercurrent exchange process to obtain O2 dissolved in the water. This increases efficiency.
• Parts of the respiratory system include the Trachea, Bronchi, Bronchioles, Alveoli
• During inspiration (inhalation), the diaphragm and intercostal muscles contract.During exhalation, these muscles relax. The diaphragm domes upwards.
• The alveoli are moist, thin-walled pockets which are the site of gas exchange. A slightly oily surfactant prevents the alveolar walls from collapsing and sticking together.
• The respiratory surface is made up of the alveoli and capillary walls. The walls of the capillaries and the alveoli may share the same membrane.
• Air entering the lungs contains more oxygen and less carbon dioxide than the blood that flows in the pulmonary capillaries.
• Hemoglobin binds to O2 that diffuses into the blood stream.
• 7% of CO2  is dissolved in the blood. 20% can bind to hemoglobin for transport.
• 73% of carbon dioxide can dissolve in plasma. Carbonic acid is formed which ionizes into bicarbonate ions and protons. Hemoglobin attaches the extra H+ to lower the acidity of the blood. The reverse occurs at the lungs!
• Diffusion of oxygen from lungs to blood is rapid because: 1.Active transport moves oxygen.2.Hemoglobin takes up oxygen, keeping plasma concentration low.3.Blood plasma is oxygen-rich.
• Most oxygen in the blood are 1.In the white cells.2.Bound to hemoglobin.3.Combined with carbon to make carbon dioxide.4.Dissolved in the plasma.
• toxic nicotine, which paralyzes cilia that normally clean the lungs.
• Smoking can also lead to emphysema. Alveoli become dry and brittle, and eventually rupture.
• People with cystic fibrosis have trouble with lung infections because their lung

  mucus is thick and sticky.
• Three main blood vessels are arteries, veins and capillaries
• Arteries carry blood away from the heart, have thick muscular walls with elastic tissue, and have high blood pressure and flow
• Arterioles are branches that come from the main arteries. They contain smooth muscle controlled by the nervous system. They control blood flow.
• Veins carry blood to the heart, have thin walls, little elastic tissue, low blood opressure, and valves are present to prevent backflow of blood
• Capillaries link up arteries and veins. Their walls are one cell thick and are large enough for one red blood cell at a time
• Circulatory system transports nutrients, gases, wastes, other chemicals and molecules such as hormones
• Circulatory system has three general components:

  1.) a fluid transports materials

  2.) A systems of vessels in which the fluid moves

  3.) A pump to move the fluid through the vessels
• Half of blood is filled with plasma, the rest is blood cells
• Plasma is a fluid in which the solid blood cells bath. Nutrients, gases, wastes and hormones are also transported
• Air within alveoli must be exchanged regularly to provide a fresh supply of oxygen to your lungs and to carry carbon away from lungs for cellular respiration\
• Air always moves from an area of high pressure to low pressure
• The diaphram is responsible for most of the changes in pressure in the lungs
• Inspiration is air moving into teh during. The diaphragm contracts and moves down while the muscles in ribcage move up and out to cause lungs volume to increase and pressure to decrease.
• Expiration is air moving out of the lungs. The diaphram relaxes and moves up while the rib cage muscles move down causing volume in lungs to decrease and pressure to increase
• Pleural membrane is a tissue that protects the delicate tissue of the lungs and keeps the lungs attached to the chest cavity. There is also a thin liquid which allows lungs to move more freely
• If air is let into pleural space, then your lung will collapse and not function
• The heart has a double pump
• There are two sides of the heart seperated by the septum
• Each pump of the heart has an atrium (thin wall) and a ventricle (thick wall)
• Atria recieve blood and pump it to the ventricles