Ch 6 - Respiratory

Question 1

Respiratory Pathway

Answer 1

• In through nares then filtered by vibrissae (nasal hairs) in the nasal cavity
• pharynx (food and air) and larynx (only air)
  
  • larynx contains vocal cords
• glottis (opening of larynx) covered by epiglottis
• Into trachea then bronchi, bronchioles, alveoli
• surfactant in lungs to reduce surface tension and keep lungs from collapsing

Question 2

Lungs

Answer 2

• In thoracic cavity
• pleura surround each lung
  
  • visceral - directly on lung
  • parietal - outer pleura
• Interpleural space - between visceral and parietal
  
  • can fill with air (pneumothorax)
• Diaphragm - thin muscle that seperates thoracic and abdominal cavities.
  
  • muscle for inhilation
  • under somatic control

Question 3

Inhalation

Answer 3

• Active process
• diaphragm and external intercostal muscles used to expand chest cavity
  
  • intrathoracic volume increases (volume of chest cavity)
  • decrease intrapleural pressure
  • Boyles Law
• negative-pressure breathing - lower intrapeural pressure compared to lungs (atmospheric pressure)
  
  • air sucked in

Question 4

Exhalation

Answer 4

• not required to be active process
• diaphragm relaxes and decreases chest volume
• lungs are elastic and decreases volume, increase pressure
• Active exhalation uses internal intercostal muscles and abdominal muscles to quickly contract chest cavity

Question 5

Lung Capacities and Volumes

Answer 5

• Spirometer - measure lung capacity
• Total lung capacity (TLC) - max volume, inhale completely (about 6-7L)
• Residual Volume (RV) - minimum air in lungs after complete exhale
• Vital Capacity (VC) - difference between min and max volumes (TLC - RV)
• Tidal Volume (TV) - volume of normal breath
• Expiratory reserve volume (ERV) - additional air forcebly exhaled after normal exhale
• Insiratory reserve volume (IRV) - additional air inhaled after normal inhalation

Question 6

Breathing Regulation

Answer 6

• controlled by neurons in ventilation center of medulla oblongata
• neurons have chemoreceptors that respond to CO2
  
  • hypercarbia/hypercapnia is increased CO2 and causes increased respiratory rate
  • only receptive to low O2 in times of significant hypoxemia

Question 7

Gas Exchange

Answer 7

• Diffuse across alveoli walls (one cell thick) and capillaries
• Use concentration gradient - no enegry required for gas transfer
• low oxygen blood in from pulmonary arteries and oxygenated blood out via pulmonary veins

Question 8

Thermoregulation via respiratory

Answer 8

• vasodilation - dissapate heat
• visoconstriction - conserve heat
• panting - used by animals to cool down

Question 9

Immune function of respiratory

Answer 9

• Vibrissae - hair in nose
• Lysozyme in nasal cavity, attack peptidoglycan
• internal airways have mucus and cilia
  
  • mucociliary escalator
• Macrophages in alveoli
• antibodies in mucosal surfaces
• mast cells in lungs promote immune response using activated antibodies
  
  • allergies

Question 10

pH control via Respiratory

Answer 10

• bicarbonate buffer system
• CO2 + H2O = H2CO3 = H + HCO3
• homeostais pH of 7.35-7.45
• acidemia - chemoreceptors send signal for greater respiratory rate
  
  • greater H+ causes shift left and more CO2 which also increases resp rate
• alkalemia - slow resp rate and CO2 retained, shift right and decrease pH
• kidneys also control pH, but on a long term scale