Biology

• Types of gas exchange

  • Skin system (integumentary system)
  • Gills system
  • Tracheal system (spiracles)
  • Lungs system
• Skin system (integumentary system)

  Breath in oxygen through their moist body surface. Example: frog, worm
• Gills system


  The membrane in most aquatic animals, these are able to get oxygen that has been dissolved in water into their blood stream. Example: fish
• Tracheal system (spiracles)


  Gas exchange in some animals like insects takes place in their trachea, which are several air tubes that form a network in their bodies. Example: insects
• Lungs system


  A pair of organs divided into small chambers filled with capillaries and air sacs. Example: land animals, human
• Respiratory system


  The set of organs that allows a person to breathe and exchange oxygen and carbon dioxide throughout the body
• Major tasks of the respiratory system

  • Exchanging air between the body and the outside environment (external respiration)
  • Bringing oxygen to the cells and removing carbon dioxide from them (internal respiration)
  • Biochemical oxidation of glucose and consequent synthesis of ATP in the cell (cellular respiration)
• Parts of the respiratory system

  • Lung
  • Bronchial tubes
  • Nose
  • Mouth
  • Trachea
  • Diaphragm
• Functions of the respiratory system

  • Supplies the body with oxygen and disposes of carbon dioxide
  • Filters inspired air
  • Produces sound
  • Contains receptors for smell
  • Rids the body of some excess water and heat
  • Helps regulate blood pH
• Breathing (pulmonary ventilation)


  1. Inhalation (inspiration) - draws gases into the lungs

  2. Exhalation (expiration) - forces gases out of the lungs
• External respiration


  Air from the outside environment enters the nose or mouth during inspiration (inhalation)
• Parts of external respiration

  • Nose and nasal cavity
  • Paranasal sinuses
  • Pharynx (throat)
  • Larynx
• Parts of the nose

  • Nostril
  • Nasal septum
  • Nasal cavity
  • Oral cavity
  • Mucous membrane
• Pharynx


  Common space used by both the respiratory and digestive systems, commonly called the throat
• Sections of the pharynx

  • Nasopharynx
  • Oropharynx
  • Laryngopharynx
• Larynx


  Voice box, a short, somewhat cylindrical airway that ends in the trachea
• Trachea


  A flexible tube also called the windpipe, extends through the mediastinum and lies anterior to the esophagus and inferior to the larynx
• Lungs


  • Left lung - divided into 2 lobes, smaller than right lung
  • Right lung - divided into 3 lobes, located more superiorly in the body
• Pleura


  The outer surface of each lung and the adjacent internal thoracic wall are lined by a serous membrane
• Pleural cavities


  The potential space between the serous membrane layers
• How lungs work


  1. Air enters lungs through bronchi

  2. Alveoli are where gas exchange takes place between air and blood

  3. Oxygen travels from alveoli into bloodstream

  4. Carbon dioxide travels from bloodstream into alveoli and is exhaled
• Parts involved in how lungs work

  • Branch of pulmonary vein
  • Branch of pulmonary artery
  • Bronchiole
  • Terminal bronchiole
  • Respiratory bronchiole
  • Capillary beds
  • Alveoli
• Breathing


  1. Diaphragm contracts, rib cage rises, chest cavity expands, creating partial vacuum that draws air into lungs (inhalation)

  2. Diaphragm relaxes, rib cage lowers, pressure in chest cavity greater than atmospheric pressure, air pushed out of lungs (exhalation)
• Proper care of the respiratory system

  • Stop smoking and stay away from secondhand smoke
  • Avoid indoor and outdoor air pollution
  • Avoid exposure to people with flu or other viral infections
  • Exercise regularly
  • Eat a healthy, balanced diet
  • Maintain a healthy weight
  • See your doctor for an annual physical
• Digestive System


  Food undergoes six major processes: 1. Ingestion, 2. Propulsion, 3. Mechanical digestion, 4. Chemical digestion, 5. Absorption, 6. Defecation
• Ingestion


  Process of eating
• Propulsion


  Passing of food down the GI tract
• Swallowing


  • Voluntary
• Peristalsis


  • Reflex, involuntary, involves alternating contractions of muscles in body walls of GI organs
• Mechanical digestion


  Prepares food for chemical digestion, includes chewing, mixing with saliva by tongue action, churning in stomach
• Chemical digestion


  Catabolic steps in which food is broken down to basic building blocks, accomplished by enzymes in digestive juices
• Absorption


  Passage of food particles into the blood-lymph
• Defecation


  Elimination of indigestible food substances
• Main Parts of Human Digestive System

  • Mouth
  • Esophagus
  • Stomach
  • Small Intestine
  • Large Intestine
• Accessory Parts of Human Digestive System

  • Liver
  • Pancreas
  • Gallbladder
  • Salivary Gland
• Mouth


  There are two major processes which take place: Mastication (Chewing) and Secretion of Saliva
• Mastication (Chewing)


  • Breaks down large food molecules, increases surface area of food particles
• Saliva


  • Contains salivary amylase (ptyalin) that digests starch to maltose, lubricates and moistens food
• Salivary Glands


  • Parotid
  • Submaxillary
  • Sublingual
• Teeth


  Bonelike structure in the mouth used for mastification or chewing, with parts: Crown, Neck, Root