chapter 13 part b

Chapter 13 – Respiration – Part B

9. Gas exchange via diffusion only- gas crosses the respiratory membrane by diffusion

a.    Oxygen enters the blood

b.    Carbon dioxide enters the alveoli

c.    Macrophages “dust cells”- add protection by picking up bacteria, carbon particles, and other debris

d.    Surfactant a lipid molecule- coats gas-exposed alveolar surfaces

10.  Events of respiration

a.    Breathing= pulmonary ventilation- moving air in and out of the lungs

b.    External respiration- gas exchange between pulmonary blood and alveoli:

                                          i.    Oxygen is loaded into the blood

                                        ii.    Carbon dioxide is unloaded from the blood

c.    Respiratory gas transport- transport of oxygen and carbon dioxide via the bloodstream

d.    Internal respiration- gas exchange between blood and tissue cells in systemic capillaries

e.    Mechanics of breathing (pulmonary ventilation)

f.    Mechanical process that depends on volume changes in the thoracic cavity

g.    Volume changes àpressure changes –volume changes lead to pressure changes, which lead to the flow of gases to equalize pressure

h.    Charles’ Law: P = 1/V

i.      Two phases:

                                          i.    Inspiration= inhalation- flow of air into lungs

                                        ii.    Expiration= exhalation- air leaving lungs

                                       iii.    Yoga

j.     Inspiration details- size of thoracic cavity increases

                                          i.    Two sets of muscles- diaphragm and external intercostals muscles contract

                                        ii.    External air pulled into chest due to:

1.     Increase in intrapulmonary volume (volume in the lungs)

2.    Decrease in gas pressure

k.    Expiration details

                                          i.    Passive process which depends on natural lung elasticity

                                        ii.    Air pushed out of lungs due to: relaxation of muscles

1.     Decrease in intrapulmonary volume (volume in lungs)

2.    Increase in gas pressure

3.    Forced expiration can occur mostly by contracting internal intercostals muscles to depress the rib cage

l.      Thoracic cavity pressure

                                          i.    Negative relative to the lungs

                                        ii.    Differences between lungs & pleural space

11.  Nonrespiratory gas movements – reflexes or voluntary action

a.    Coughing-clears lungs of debris

b.    Sneezing – clears lungs of debris

c.    Crying -emotionally induced mechanism

d.    Laughing- similar to crying…emotionally induced

e.    Hiccup- reflex, sudden inspirations

f.    Yawning-very deep inspiration, not getting enough air, take in more oxygen

                                          i.    Pandiculation = yawning +stretching together

g.    Talking-communication

12.  Respiratory volumes and capacities

a.    Normal breathing = tidal volume (TV) = moves about 500mL of air with each breath

                                          i.    Affected by

b.    Inspiratory reserve volume (IRV) = amount of air that can be taken in forcibly over the tidal volume. Usually between 2100 and 3200mL

c.    Expiratory reserve volume (ERV) = amount of air that can be forcibly exhaled. About 1200 mL

d.    Residual volume (RV) = air remaining in lung after expiration. about 1200mL

e.    Dead space volume (DSV) =

f.    Functional volume = air that actually reaches the respiratory zone..low percentage

g.    Capacities = two or more volumes together

                                          i.    Spirometer

                                        ii.    Vital capacity (VC) = TV + IRV + ERV- total amount of exchangeable air

                                       iii.    Total Lung Capacity (TLC) = VC + RV

13.  Respiratory sounds

a.    With a stethoscope- monitored with

b.    Two sounds

                                          i.    Bronchial- produced by air rushing through trachea and bronchi

                                        ii.    Vesicular breathing- soft sounds of air filling alveoli

14.  External respiration details

a.    Oxygen loaded into the blood

                                          i.    Alveolar concentration

                                        ii.    Diffusion moves oxygen towards the area of lower concentration

                                       iii.    Pulmonary capillaries blood gains oxygen

b.    Carbon dioxide unloaded from blood

                                          i.    Blood returning from tissues has higher concentration of carbon dioxide than air in the alveoli

                                        ii.    Pulmonary capillary blood gives up carbon dioxide to be exhaled

                                       iii.    Blood leaving lungs has more oxygen and less carbon dioxide than when it entered

15.  Gas transport in blood

a.    Oxygen

                                          i.    Almost all oxygen as HbO₂ – most oxygen attached to hemoglobin to form oxyhemoglobin. (HbO2)=98%

                                        ii.    Small amount is carried in the plasma membrane 2%

                                       iii.    Carbon monoxide will outcomplete oxygen for hemoglobin sites..resulting in suffocation due to CO poisoning

b.    Carbon dioxide

                                          i.    Most carried as HCO₃^- in the plasma membrane

                                        ii.    Small amount carried inside red blood cells on hemoglobin and dissolved in plasma

                                       iii.    Getting out of blood:

1.     HCO₃^- + H⁺ à H₂CO₃ à H₂O + CO₂

16.  Internal respiration = exchange between

a.    Opposite what happens in the lungs

                                          i.    Carbon dioxide

                                        ii.    Oxygen

17.  Neural control of respiration

a.    Phrenic and intercostals nerves

b.    Rate and depth of breathing

                                          i.    Medulla

                                        ii.    Pons

c.    Rates

                                          i.    Normal

                                        ii.    Hypernea

d.    Other factors controlling breathing

                                          i.    Physical

1.     Body temperature

2.    Exercise

3.    Talking

4.    Coughing

                                        ii.    Volition

                                       iii.    Emotional factors

                                       iv.    Chemical factors

1.     Getting rid of CO₂

2.    Oxygen levels

                                         v.    Hyperventilation

                                       vi.    Hypoventilation