Process of Breathing 50 Pulmonary ventilation Breathing Involves

Process of Breathing

50. Pulmonary ventilation - Breathing Involves two phases: Inspiration Expiration

A. Boyle’s Law • if the volume increases, then the pressure must decrease (or vice versa)

Boyle’s Law a. Gasses flow from areas of high pressure to low pressure to become equal

B. Inspiration – air flows into lungs

a. Inspiratory muscles • Diaphragm –dome shaped muscle, separates the thoracic cavity from the abdominal cavity

Inspiratory muscles • Intercostals – muscles between the ribs (costals)

Steps of inspiration 1) Respiratory muscles contract (diaphragm descends, rib cage rises)

Steps of inspiration 2) Thoracic cavity volume increases

Steps of inspiration 3) Lungs stretched, intrapulmonary volume increases

Steps of inspiration 4) Intrapulmonary pressure drops

Steps of inspiration 5) Air flows into lungs until pressure inside is equal to pressure outside

C. Expiration – gases exit lungs

Steps of Expiration • 1) Respiratory muscles relax (diaphragm rises, rib cage descends

Steps of Expiration • 2) Thoracic cavity volume decreases

Steps of Expiration • 3) Elastic lungs recoil passively, intrapulmonary volume decreases

Steps of Expiration • 4) Intrapulmonary pressure rises

Steps of Expiration • 5) Gases flow out of lungs until inside and outside pressure are equal

Inspiration or expiration?

Inspiration or expiration?

Lung Capacity

A. Tidal Volume (TV) = the amount of air going into or out of the lungs on single breath An adult’s lungs can hold about 6 liters of air. During normal breathing, only about ½ liter is exchanged

B. Expiratory reserve Volume(ERV) = air left to be exhaled AFTER normal breathing (exhalation)

C. Inspiratory Reserve Volume(IRV)= the amount of air you can take in after tidal volume

D. Vital Capacity (VC) = total amount of air you can move a. VC = TV + IRV + ERV Trained athletes or singers have a large vital capacity

E. Inspiratory Capacity (IC) = how much air you bring in a. IC = TV + IRV

F. Residual Volume (RV) = what is left in the lungs that you can not move! This keeps the lungs partially inflated at all times

G. DEAD SPACE • Air in passage way that never makes it to gas exchange.

IRV ERV

http: //www. youtube. com/watch? v=4 y E 89 Z 4 q. Ti. E • Calculate your vital capactiy

52. Control of Breathing • Both voluntary and involuntary

A. Respiratory Centers a. Medulla Oblongata b. Pons

B. Reflex Control • AKA autonomic control

Chemoreceptor Reflex a. Responds to the amount of CO₂ in the blood

Chemoreceptor Reflexes b. If. . CO₂ THEN respiration

C. Protective reflexes a. What happens when people are poisoned by toxic gases? b. 1. Stop breathing! 2. Start coughing!

53. External respiration • Getting air from the atmosphere into the blood. (gas to dissolve into liquid)

A. Diffusion • Oxygen diffuses across alveolar membrane into the blood stream of capillaries

B. Hemoglobin (Hb) a. Oxygen is not very soluble, so it binds to the carrier hemoglobin on the RBC.

Hemoglobin b. Hb + O 2 Hb. O 2 (oxyhemoglobin)

Hemoglobin c. The hemoglobin contains iron, this is where O 2 attaches. d. Iron Hb RBC

C. CO poisoning a. Carbon monoxide: colorless, odorless b. Attached to Hb before oxygen does and you suffocate

D. Hyperventilating • Breathing faster and/or deeper than normal usually from anxiety or stress Build up of too much oxygen and not enough CO₂

54. Other Respiratory Issues A. Pneumonia – inflammation of the alveoli, fluids accumulate, difficult to breathe

Other Respiratory Issues B. Emphysema – alveoli lose elasticity and stay inflated, difficult to breathe

Other Respiratory Issues C. Cystic Fibrosis – inherited, thick, sticky mucus accumulates in lungs

Yawning • What causes yawning? Still not sure!

Hiccups • Diaphragm becomes irritated: – eating too quickly or too much – irritation in stomach or throat – feeling nervous or excited

Labeling the Respiratory System