respitory system

STRAND 10.1: LIVING THINGS AND THE ENVIRONMENT

SUB-STRAND 10.1.1: STRUCTURE AND LIFE PROCESSES

Lesson Outcome

  1. Define respiration; identify gases exchanged (oxygen and carbon dioxide).

  2. Describe inhalation and exhalation processes.

  3. Test for carbon dioxide using lime water.

Respiratory System Overview

  • Definition: Group of organs and tissues facilitating breathing.

  • Primary Organs: Lungs; enable gas exchange.

  • Components: Airways, blood vessels, respiratory muscles.

Functions of the Respiratory System

  1. Gas exchange (O$2$ and CO$2$) between blood and air.

  2. Speech and vocalization.

  3. Sense of smell.

  4. Controls body acid-base balance.

  5. Promotes blood and lymph flow through breathing movements.

Lungs and Gas Exchange

  • Contain alveoli (tiny air spaces).

  • Alveoli walls: thin; surrounded by capillaries.

  • Oxygen: Diffuses from air to blood.

  • Carbon Dioxide: Diffuses from blood to air.

Breathing Processes

  • External Respiration: Exchange of O$2$ and CO$2$.

  • Inhalation:

    • Diaphragm contracts, increasing thoracic volume.

    • External intercostal muscles contract, rib cage moves upward/outward.

  • Exhalation:

    • Diaphragm and intercostal muscles relax; thorax returns to original size, pushing air out.

Testing for Carbon Dioxide

  • Method: Bubble gas through limewater; turns milky if CO$_2$ is present.