(Slide 1) Lecture Notes: Respiratory System I. (Slide 2) The Respiratory Tract

A) Major structures and regions of the respiratory Tract/Route INTO body

1) nose 2) nasal cavity 3) pharynx 4) glottis 5) larynx 6) trachea 7) Primary (main) bronchi 8) bronchioles 9) alveoli

B) (Slide 3) Nose and Nasal Cavities

1) Structures:

(a) nares/nostrils separated by nasal septum (b) lined with mucosa

(1) epithelial tissue (2) goblet cells (3) lysozyme

(c) palate separates oral and nasal cavities

2) Function: conditions incoming air (a) warms-blood vessels (b) moistens—mucous and watery (c) cleans

(1) filters (hairs) (2) mucus traps

(d) olfaction (smell-olfactory sensory receptors)

C) (Slide 4) Pharynx

1) Structure: (a) regions: oropharynx and nasopharynx (b) tonsils: immune function

2) Function: passageway (food and air)

D) (Slide 5) Larynx 1) structure:

(a) epiglottis (1) elastic cartilage (2) closes glottis during swallowing

(b) glottis: opening (c) hyaline cartilages

(1) adam’s apple (d) vocal cords

(1) CT

2) (Slide 6)Function: (a) passageway for air (b) prevents food from entering airways (c) speech

(1) vocal cords vibrate as air passes through producing sounds

(2) tighter the vocal cords stretched, the higher the pitch

E) (Slide 7) The Bronchial Tree:

1) Major Structures (a) trachea (b) primary bronchi (c) secondary bronchi (d) tertiary bronchi (e) bronchioles (f) alveoli (microscopic)

2) (Slide 8) Functionally divided into two zones:

(a) conducting zone

(b) respiratory zone

3) (Slide 9) Trachea

(a) Structure: (1) C-shaped hyaline (2) epithelium lines lumen

(a) goblet cells (b) pseudostratified ciliated columnar

(b) function: (1) keeps passageway open (conducting zone) (2) cleans—traps

4) (Slide 10) Bronchi (a) structure:

(1) bachnes off trachea and enter hilum of lungs (indentation) (2) hyaline cartilage (3) continue to branch

(a) smaller diameter (b) cartilage rings�plates in bronchioles

(b) function: conducting pathway for air flow in/out

5) (Slide 11)Lungs (a) structure:

(1) soft/spongy

(2) approximately 2 ½ pounds (3) lobes (3 right and 2 left) (4) pleural cavity (5) surrounded by rib cage/bony thorax (6) diaphragm (inferior) (7) (Slide 12) Pleural membranes

(a) structure:

1. parietal pleura—line thoracic cavity 2. visceral pleura—cover surface of lung lobes 3. pleural (serous/water) fluid fills space between parietal and visceral pleura

(b) function: 1. decrease friction during inhalation/exhalation 2. surface tension holds membranes together during ventilation

(8) (Slide 13) Alveoli or Alveolar Sacs (a) structure:

1. simple squamous epithelium—thin/fast diffusion

2. pulmonary capillaries 3. surfactant: lipid that decreases

surface tension allowing alveoli to expand

4. macrophages (phagocytes)

(b) function: External Respiration

II. (Slide 14)Mechanism of Breathing

A) Definitions:

1) breathing or ventilation

2) external respiration

3) internal respiration

4) (aerobic) cellular respiration: Glucose + Oxygen � carbon dioxide + water

B) (Slide 15)Regulation of Inspiration/Inhalation

1) Respiratory Center (a) brainstem: medulla oblongata (b) chemoreceptors (sensory receptors)

(1) carbon dioxide (2) hydrogen ions

(c) increases inspiration (rate and depth)

C) (Slide 16-17)Mechanism of Inspiration (Inhale)

1) thoracic cavity volume:

2) muscles contract: (a) intercostals (between ribs) lift ribs up and out (b) diaphragm flattens

3) abdominal muscles relax—abdominal organs drop

D) Mechanism of Exhalation (exhale)

1) opposite of inhalation

III. (Slide 18)Gas Exchange within the Body

A) Diffusion: 1) movement of a substance from an area of high concentration to an area of low

concentration 2) due to substances own kinetic energy 3) gases move based on partial pressures

(a) gas molecules bound on walls (pressure) (b) more molecules/more bouncing/higher pressure (c) each gas exerts its own partial pressure

(1) oxygen gas (2) carbon dioxide (3) nitrogen gas

(d) all gases together makes up atmospheric pressure

B) (Slide 19)External Respiration: gas exchange between external environment (alveoli) and the blood

1) CO2 2) O2

C) (Slide 20)Internal Respiration: gas exchange between internal environment of body tissues and the blood

1) CO2 2) O2

D) (Slide 21)Carbon Dioxide Transport

1) dissolved gas molecules in plasma (a) not very soluble in liquids/water (b) nonpolar/hydrophobic (c) very little transported

2) hemoglobin (RBC protein) (a) two active sites—O2 and CO2 (b) inefficient 20-30%

3) (Slide 22)Bicarbonate: most CO2 transported

(a) internal respiration (right)

CO2+H2O�H2CO3carbonicanydrase

�H++HCO3-

tissues make CO2 gas and converted to bicarbonate ion in blood for transport (b) external respiration (left)

CO2+H2O�H2CO3carbonicanydraseH++HCO3

-

blood arrives at lungs and bicarbonate converted back to CO2 where it is excreted by the lungs as waste.

E) (Slide 23-25)Oxygen Transport

1) small amount transported as dissolved gas molecules in plasma

2) hemoglobin

(a) quaternary proteins within RBCs (b) 4 heme groups / iron groups (c) each heme carries 4 oxygen (d) 200-250 million hemoglobins per RBC

3) Factors that affect Hemoglobin’s ability to carry oxygen

(a) concentration gradient/partial pressure—moves from high to low (b) temperature

(1) cooler temperatures promote loading (2) warmer (active) promote unloading

(c) pH (1) alkaline promotes loading (2) acidic (active tissues) promote unloading

Concentration: ↑O2 in alveolus Cooler External Environment pH alkaline/basic

↓H+ as CO2 excreted

Concentration: ↑O2 in blood Warmer Active Body Tissues pH ↑H+ as CO2 generated by active body tissues