science reviewer 1

• Our body needs oxygen in order to live
• Respiration


  The process of organisms exchanging gases with the environment
• Respiration includes the intake of oxygen and its delivery to the cells of the different parts of the body
• Respiration or breathing is a continuous cycle
• An average person breathes 20,000 times a day
• Breathing

  1. Inhalation - body takes in oxygen

  2. Exhalation - body expels carbon dioxide
• Respiratory system


  The body system that allows the exchange of gases
• Parts of the respiratory system

  • Upper tract - nose, nasal cavity, pharynx
  • Lower tract - larynx, trachea, bronchial tubes, lungs
• Nose


  • Mostly made of cartilage, flexible and strong
  • Has two openings called nostrils
  • Nostrils lined with small hairs called cilia to filter dust and particles
• Nasal cavity


  • Lining is moist due to mucus
  • Lined with tiny hairs or cilia to filter dust and particles
  • Warms and moistens air that enters the body
• Pharynx


  • Also called the throat
  • Connects the nose and mouth, acts as a passageway for air and food
• Tonsils


  • Found at the opening of the pharynx, destroy bacteria that enter the body
• Larynx


  • Also called the voice box
  • Found at the lower end of the pharynx
  • Vocal cords vibrate to produce sound
• Epiglottis


  • Covers the larynx
  • Raised during breathing to allow air flow, pressed down during swallowing to prevent choking
• Trachea


  • Also called the windpipe
  • Lined with mucus to prevent dust and particles from entering the lungs
  • Connects to the lungs through bronchi or bronchial tubes
• Bronchial tubes


  • Two tubes that carry air into the lungs
  • Branch into smaller tubes called bronchioles
• Bronchioles


  • At the end of each bronchiole is a bunch of tiny air sacs called alveoli
• Alveoli


  • The exchange of oxygen and carbon dioxide happens in the alveoli
• Lungs


  • Enclosed in a coating called pleura which allows the lungs to slide freely as they expand and contract
• Diaphragm


  • Dome-shaped muscle that controls breathing
  • Contracts and pulls downward during inhalation to increase space for the lungs
  • Expands and moves upward during exhalation to reduce space for the lungs
• Respiration


  1. Inhalation - air enters through nostrils, goes through nasal cavities, pharynx, larynx, trachea, bronchi, bronchioles, alveoli where oxygen and carbon dioxide are exchanged

  2. Exhalation - air with carbon dioxide travels out through the same path in reverse
• The air we breathe is a mixture of gases - 78% nitrogen, 21% oxygen, 0.04% carbon dioxide, and other gases
• We do not absorb all the oxygen in the air we breathe, which is why we can supply oxygen to someone during mouth-to-mouth resuscitation
• Nebular theory


  The sun and planets are formed from a rotating disk of dust and gases
• Nebula


  A cloud of gas and dust in space that will form heavenly bodies over a very long time
• Types of planets

  • Terrestrial planets
  • Jovian planets
• Terrestrial planets

  Also called the inner planets
• Inner planets


  • Mercury
  • Venus
  • Earth
  • Mars
• Mercury


  • Nearest planet to the sun
  • Has many craters due to no atmosphere
  • Has no moons
  • One rotation is 58 days 15 hours 30 minutes
  • One revolution around the sun is 88 days
  • Considered the fastest planet
• Venus


  • Second planet from the sun
  • Brightest object in the sky besides the sun
  • Commonly referred to as the morning and evening star
  • Considered the twin planet of Earth
  • Hottest planet due to thick carbon dioxide atmosphere and greenhouse effect
  • Clouds are mostly sulfuric acid
  • Rains are acid rain
  • Surface has mountains and volcanoes
  • First planet studied with space in 1962
  • Has no moons
  • Gravity as strong as Earth
  • One rotation is 116 days 18 hours
  • One revolution is 225 days
  • Rotates only twice in one year
• Earth


  • Third planet from the sun
  • The only living planet
  • Rich in liquid water that supports life
  • Has an atmosphere that supports and protects life
  • Atmosphere burns most meteors before reaching surface
  • Has one large moon
  • One rotation is 23 hours 56 minutes
  • One revolution is 365 1/4 days
• Mars


  • Known as the red planet
  • Surface appears red/yellow due to iron oxide
  • Atmosphere is 18% composed of carbon dioxide, small amounts of oxygen and nitrogen
  • Has water in atmosphere but not enough to form clouds
  • One rotation is 24 hours 37 minutes
  • One revolution is 687 days
  • Has the largest volcano in the solar system, Mount Olympus Mons
  • Gravity is 2/5 as strong as Earth
  • Has two irregularly shaped moons, Phobos and Deimos
• Mercury, Venus, Earth, and Mars are called terrestrial planets because they have rocky surfaces and metal cores
• Asteroid belt


  Group of asteroids found between the orbits of Mars and Jupiter, separating the terrestrial and jovian planets
• Outer planets (gas giants)


  • Jupiter
  • Saturn
  • Uranus
  • Neptune
• Jupiter


  • Largest gaseous planet
  • More than 11 times the size of Earth
  • Generates strong gravitational force
  • Atmosphere is hydrogen, helium, methane, ammonia, and water vapor
  • Has a faint dust ring
  • Has at least 63 moons, including the 4 Galilean moons of Ganymede, Callisto, Europa, and Io
  • Ganymede is the largest moon in the solar system
  • Io has active volcanoes
  • Callisto is mostly rock and ice
  • Has a large counterclockwise rotating storm called the Great Red Spot
  • One rotation is 9 hours 56 minutes
  • One revolution is 12 years
• Saturn


  • Second largest planet
  • Lowest density
  • 9.5 times larger than Earth
  • One rotation is 10 hours 39 minutes
  • One revolution is 29 years
  • Atmosphere is hydrogen, helium, methane, and water vapor
  • Has at least 31 moons, the largest being Titan
• Uranus


  • Third largest planet
  • Has a system of 11 thin dark rings
  • Atmosphere is hydrogen, helium, and methane which gives it a bluish-green color
  • Radiates the same amount of solar energy it receives
  • Axis of rotation is tilted 84 degrees, so its north pole faces the sun for half of its 84 year revolution
  • One rotation is 17 hours 14 minutes
  • One revolution is 84 years
  • Gravity is a little stronger than Earth
  • Has at least 21 moons, the largest being Titania
• Neptune


  • Fourth largest planet
  • Has an elliptical orbit
  • Atmosphere is methane which gives it a bluish-green color
  • Has a dark storm called the Great Dark Spot
  • Has the fastest winds in the solar system
  • Has at least 11 moons, the largest being Triton
  • One rotation is 16 hours 6 minutes
  • One revolution is 165 years
• Planets in order from closest to farthest from the sun

  • Mercury
  • Venus
  • Earth
  • Mars
  • Jupiter
  • Saturn
  • Uranus
  • Neptune