Unit 1: Respiration PDF

Unit 1: Respiration  1.1 - The human respiratory system Lesson objectives Learn the names of different parts of the human respiratory system Observes carefully, and record your observations, as the structure of lungs is demonstrated Keywords Aerobic respiration, ar sac,...

Unit 1: Respiration  1.1 - The human respiratory system Lesson objectives Learn the names of different parts of the human respiratory system Observes carefully, and record your observations, as the structure of lungs is demonstrated Keywords Aerobic respiration, ar sac, bronchiole, bronchus, cartilage, larynx, respiratory system, trachea, vocal cords, voicebox, windpipe Why we need oxygen? Respiration is a series of chemical reactions that happens inside every living cell.  1.2 - Gas exchange Lesson objectives Find out how oxygen gets into your blood from the air, and how carbon dioxide goes out into the other direction Learn why the air sacs in the lungs need to be very small Compare how much CO2 in the air you breathe in and the air you breathe out Keywords Alveoli, analogy, capillaries, diffusion, expired air, gas exchange, haemoglobin, inspired air, limewater Air sacs The photograph shows a tiny part of lungs. Lungs looks like mostly holes. These holes are called air sacs or alveoli. Lots of tiny blood vessels are wrapped around the air sacs. These blood vessels are called capillaries. Structure of an air sac The air sac has a wall made of one layer of cells. There are blood capillaries outside alveolus. They are pressed tightly against the alveolus. Capillary wall is single layer thick. Exchange in air sacs Oxygen from the air goes into the blood. Carbon dioxide from the blood goes into the air - gas exchange Oxygen → to all cells of the body through blood Carbon dioxide → collected from body cells/organs → heart → lungs Oxygen particles move from the air (more of them), through the thin-walled cells into the blood (containing less oxygen). This movement of particles from an area of higher concentration to a lower concentration is called diffusion. CO2 from the blood diffuses into the alveoli. Why are air sacs so small? Oxygen particles move from the air (more of them), through the thin-walled cells into the blood (containing less oxygen). This movement of particles from an area of higher concentration to a lower concentration is called diffusion. CO2 from the blood diffuses into the alveoli. Why are air sacs so small? - Too tiny too fit in many numbers - Surface in our lungs is larger - Diffusion of gases is easier and faster Example of diffusion