UNIT 5 - RESPIRATORY SYSTEM Flashcards
Respiratory system
Group of organs and tissues used for gas exchange (breathing)
Main respiratory structures (8)
- Nasal cavity (nose
- Mouth
- Pharynx (throat)
- Larynx (voice box)
- Trachea (windpipe)
- Bronchi (large airways)
- Bronchioles (small airways)
- Lungs
Nasal cavity
Provides airway for respiration and moistens/warms the entering air. Filtering of air by hairs the mucous (lysozyme) and contains olfactory receptors
Pharynx
Common passageway for air from nasal and buccal cavity to trachea
Larynx
Common path for food and air to separate controlled by swallow reflex and epiglottis. Also the voice box
Epiglottis
Flap of cartilage that protects the glottis, opening to the trachea
Trachea
Long U shape tube connecting larynx to lungs supported by cartilage rings to put air into and out of the lungs
Thyroid cartilage
2 large plates of cartilage on anterior wall of larynx (adams apple)
Bronchi
Two primary bronchi branch into secondary and tertiary bronchi and takes air into lungs from trachea
Right primary bronchus
Serves the right lung
Left primary bronchus
Serves the left lung
Bronchioles
Further divisions of the tertiary bronchi, the air passage inside the lungs
Branching of bronchial tree in order (9)
- Trachea
- Primary bronchi
- Secondary bronchi
- Bronchioles
- Terminal bronchioles
- Respiratory bronchioles
- Alveolar duct
- Alveolar sac
- Alveoli
Alveoli
Air sacs at the end of bronchioles made of a single layer of squamous epithelial cells surrounded by capillaries where gas exchange occurs and accounts for most of the lungs volume with the largest surface area
How many alveoli do we have
300 million
Alveolar epithelial cells (3)
- Forms nearly continuous lining
- Flat shape
- Main site of gas exchange
Other characteristics of alveolar cells (3)
- Free surfaces contain microvilli secreting surfactant
- Reduce tendency to collapse
- Macrophages
Breathing
Process of getting oxygen into lungs and carbon dioxide out of the lungs
Thoracic cavity
Sealed cavity that houses the lungs and the heart
Rib cage
Surrounds the lungs for protection
Diaphragm
Muscle that helps to inhale and exhale and separates the lungs from the abdomen
Lungs
Major organ in chest to transport oxygen and remove carbon dioxide surrounded by two membranes (pleural membranes)
2 types of pleural membranes:
- Parietal pleura (outer): attached to walls of thoracic cavity and lines inner surface
- Visceral pleura (inner): Covers the lungs
Pleural cavity
Fluid filled space between pleural membranes for lubrication between lung & wall of chest cavity, and to hold the two membranes together ensuring lungs don’t collapse
Inspiration (inhalation)
Process of taking air into lungs, breathing in
Expiration (Exhalation)
Process of removing air from lungs, breathing out
Inhalation process (4)
- Air sucked in lung
- Diaphragm contracts and move down
- External intercostal muscles contract and ribs move upward & outward
- Volume of chest cavity increases, decreasing pressure to -1mm Hg in lungs until 0 (atmospheric pressure)
Exhalation process (4)
- Air is forced out lungs
- Diaphragm relaxes and moves up
- External intercostals relax and ribs move downward & inward
- Volume of chest cavity decreases, increasing pressure to +1mm Hg in lungs until intrapulmonary pressure is 0
Relaxed exhalation
Muscle relaxation
Forced exhalation
Muscle relaxation and contraction of internal intercostal and abdominal muscles to increase thoracic pressure, aiding in the rapid expulsion of air from the lungs
What mechanism controls breathing
Autonomic nervous system (involuntary), however we can control the rate and depth of breathing
Breathing control center
AKA pons and medulla oblongata (also the cardiac centers)