HUMAN RESPIRATORY SYSTEM
Human respiration includes Cellular Respiration (ch. 6) Conversion of energy in organic molecules to energy usable by humans (ATP) External & Internal Respiration Ventilation or Breathing
Human Respiratory System Transports gases between external environment & internal gas exchange surfaces. Humans have an internal surface for exchange of gases with external environment. These surfaces are in lung & are continuous with external environment through a series of tubules.
Structures External Nares: (Nostrils) intake & exhaust ports Nasal cavity: Air is warmed, filtered, & humidified by the ciliated nasal epithelium. Sinuses: spaces in bones of skull which aid in functions of nasal cavity & communicate with it. Turbinate bones: (conchae) spiral bones covered with nasal epithelium which cause turbulence & slowing of air to allow filtration, warming & humidification.
Pharynx: Junction of nasal & oral cavities Larynx: (voice box) made of cartilage & muscles which control vocal cords. Opening (glottis) is covered by cartilagenous flap - epiglottis. Prevents food from entering larynx.
Trachea: tube connecting pharynx with bronchi. Lined with pseudostratified ciliated columnar epithelium & kept open with "C" shaped cartilage rings. Cilia sweep particles up & out.
Lung: consists of Bronchi, bronchioles, alveoli, & pleura. Bronchus - branch of trachea, lined with ciliated epithelium & kept open with complete "O" cartilage rings. Bronchioles - mucous membrane, no cilia or cartilage Alveoli- thin moist air sacs, squamous epithelium, 1 cell layer thick, surrounded by capillaries (Functional unit of respiratory system). Pleural membranes: double membrane surrounding lung. contains fluid for lubrication.
Breathing (Ventilation) 1. Lungs themselves are passive 2. Intercostal Breathing Muscles of rib cage (intercostals) contract, pulling ribs out & up, increasing volume of chest cavity. Volume increases, pressure drops & air flows into lungs (inhalation). When muscles relax, volume decreases, pressure increases, air is forced out (exhalation)
3. Diaphragmic Breathing Diaphragm contracts & moves down. Volume increases, pressure decreases, air flows in (inhalation). Diaphragm relaxes, moves up, volume decreases, pressure increases, air flows out of lungs (exhalation)
Rate of breathing is regulated by pH of blood (directly related to CO2 content) Affects sensory receptors (chemoreceptors) in carotid artery & aorta that send messages to regulatory center in medulla of brain.
Malfunctions Bronchitis: inflammation of bronchial tubes Asthma: allergic response causing constriction of bronchial tubes. Emphysema: enlargement & degeneration of alveoli resulting in decreased lung capacity
1. What role do the nasal passages AND the diaphragm play in gas exchange?
2. What is the name of the respiratory surface in humans?
3. What are the four (4) phases of gas EXCHANGE in humans?
4. Name three (3) respiratory diseases that are common in cigarette smokers than in nonsmokers.
BRONCHITIS
EMPHYSEMA
LUNG CANCER
ASTHMA
PNEUMONIA
5. People with emphysema often suffer from heart problems as well 5. People with emphysema often suffer from heart problems as well. Offer an explanation for this finding.
Lung Volumes Vital Capacity: total of volume from deepest inspiration to deepest expiration Tidal volume: volume exchange under normal shallow breathing at rest. Inspiratory reserve volume: from crest of tidal volume to deepest inspiration Expiratory Reserve Volume: from trough of tidal volume to largest expiration.