1. Respiratory System

2. Functions:
1. Deliver oxygen to the circulatory system
2. Remove carbon dioxide from the circulatory system

3. 3 types of respiration:
1. External respiration – exchange of gases between the atmosphere and the blood

4. 2. Internal respiration – exchange of gases between the blood and the cells of the body

5. 3. Cellular respiration – the process by which glucose is broken down in cells to produce ATP

6. A. The Lungs
The lungs are the sites of external respiration
right lung has 3 lobes
left lung has 2 lobes

7. Lungs are located in the thoracic cavity, encased in a protective cage of bone made up of the sternum, vertebral column, and ribs

8. they sit on top of the muscle called the diaphragm, with the heart sandwiched between them

9. Both lungs are surrounded by a double-layered membrane called the pleural membrane

10. the outer pleural membrane is attached to the wall of the thoracic cavity
the inner pleural membrane is attached to the surface of the lungs

11. Between the two membranes is pleural fluid
this fluid reduces friction between the membrane as you breathe

12. Pleurisy – inflamed membranes
very painful, hurts every time you breathe
it is like having sand in your eye, it rubs with every breath
normal
pleurisy

13. B. Respiratory Passageways
1. Nose – air is filtered of large particles (dust, pollen) by nose hairs
2. Nasal cavity – lined with cilia and mucus

14. air is warmed, moistened, and filtered as it moves through the nasal cavity

16. 3. Pharynx (upper throat) – passageway for both food and air
4. Larynx (voice box) – houses the vocal cords

17. loudness of sounds is controlled by amount of air passing over cords, while pitch is controlled by how tight the vocal cords are stretched
breathing
talking
high pitch

18. food is prevented from entering the larynx by a small flap of cartilage called the epiglottis.
the epiglottis will close over the opening of the larynx when you swallow

19. 5. Trachea (windpipe) – a 10 to 12 inch tube lined with cilia and mucus
mucus traps particles that are moved by cilia up to pharynx and then swallowed

20. the trachea is kept open by C-shaped pieces of cartilage
cartilage rings

21. 6. Bronchi – the inferior end of the trachea that divides to form two branches that enter each lung
bronchus

22. the right and left bronchi divide in the lungs to form smaller branches that eventually connect to very tiny air passages called bronchioles

24. 7. Bronchioles – the smallest respiratory passageways
lined with cilia and mucus, no cartilage supports in their walls
extending from bronchioles like clusters of grapes are tiny air sacs called alveoli

26. 8. Alveoli – one cell layer thick, and they are surrounded by capillaries
location of external respiration – exchange of gases between the atmosphere and the bloodstream

27. You have approximately 300 million alveoli in each lung

28. alveoli increase the surface area of your lungs (you need a large surface area to exchange large amounts of gases
if you were to spread out all your alveoli, they would cover a tennis court

29. Bronchioles and alveoli do not have cartilage in their walls
they have a soapy-like fluid called surfactant
surfactant keeps the alveoli and bronchioles open by reducing the surface tension within them

31. C. The Mechanism of Breathing
Breathing is the result of volume and pressure changes that occur in the lungs
involves 2 processes:
inspiration
expiration

32. 1. Inspiration – taking air into the lungs
occurs when the diaphragm and intercostal muscles contract
contraction of the diaphragm causes it to flatten, contraction of the intercostal muscles causes the rib cage to expand upward and outward

33. Contraction of these 2 groups of muscles increase the volume of chest cavity
As a result, the pressure within the chest cavity is now less than atmospheric pressure – air rushes into the lungs

34. Summary of inspiration:
a. Diaphragm and intercostal muscles contract, causing
b. Volume of chest cavity to ,
c. Pressure within the chest cavity to , resulting in
d. inhalation

36. 2. Expiration – expelling air from the lungs
occurs when the diaphragm and intercostal muscles relax
relaxation of the diaphragm allows it to return to its normal dome shape

37. relaxation of the intercostal muscles cause the rib cage to move downward and inward
Relaxation of these 2 groups of muscles decreases the volume of the chest cavity.

38. As a result, the pressure within the chest cavity is now greater than atmospheric pressure – air rushes out of the lungs

39. Summary of expiration:
a. diaphragm and intercostal muscles relax, causing
b. volume of chest cavity to , causing
c. Pressure within chest cavity to , resulting in
d. expiration

42. Two important facts to remember about respiration:
1. Volume and pressure are inversely related to each other
This means that when V, P and when V , P

43. 2. Inspiration is an active process (muscles contract), while expiration is a passive process (muscles relax)

44. One respiratory cycle = 1 inhalation + 1 exhalation
most adults have 16 – 24 respiratory cycles per minute when they are at rest

45. Can you consciously control the number of respiratory cycles you have?
Up to a point by hyperventilation (rapid breathing) and hypoventilation (slow breathing)

46. Eventually you have to breathe
when you hold your breath the CO2 levels in your blood increase, causing the blood to become acidic
the more acidic, the stronger the urge to breathe

47. D. Gas Exchange and Transport
To understand gas exchange you must remember that gases move across a membrane by diffusion
Diffusion – movement of substances from a higher to a lower concentration

48. When you inhale, the air you take into your lungs is high in O2 and low in CO2
blood entering the lungs is high in CO2 and low in O2
O2 diffuses from the alveoli into the bloodstream, while CO2 diffuses from the bloodstream into the alveoli

49. When blood reaches the cells of your body, O2 will diffuse from the RBCs into your body cells.
Oxygen is transported in the bloodstream in 2 ways:
1. Dissolved in the plasma (3%)
2. Bound to hemoglobin of RBCs (97%)

50. Carbon dioxide is transported in the bloodstream in 3 ways:
1. As CO2 dissolved in plasma (8%)
2. Bound to the globin portion of hemoglobin (25%)
3. As bicarbonate ions (HCO3-) dissolved in plasma (67%)

51. Carbon dioxide is converted to bicarbonate ions within the RBCs with the help of a special enzyme called carbonic anhydrase
CO2 + H2O  H2CO3 HCO3- + H+

52. When blood rich in bicarbonate ions returns to the lungs, the reverse reaction occurs and CO2 is released

53. E. Regulation of Breathing
Your normal rate and rhythm of breathing is controlled by a region of your brain called the respiratory control center

54. it is important to realize that high levels of CO2increase your breathing rate, NOT low levels of O2

55. F. Respiratory System Abnormalities
1. Atelectasis – collapsed lung

56. 2. Bronchitis – inflammation of the bronchi

57. 3. Cystic fibrosis – excessive mucus production in lungs
Most lethal genetic disease in U.S.

58. 4. Emphysema – walls of alveoli rupture leaving less area for the exchange of gases

59. 5. Lung cancer – malignant growth of cells in lungs
Fewer than 10% of individuals diagnosed with lung cancer live more than 5 years

60. 6. Asthma – bronchioles of the lungs become constricted

62. 7. Pleurisy – inflammation of the pleura