Chapter 10 - Anatomy(RS)

1. Upper and Lower Respiratory Tracts

Upper Respiratory Tract

• Components:

  • Nose, nasal passages, sinuses, and pharynx.

• Functions:

  • Provides passageway for respiration.

  • Houses receptors for smell.

  • Filters larger foreign materials from incoming air, entrapping microorganisms in mucus.

  • Moisten and warm incoming air.

  • Provides resonating chambers for voice.

Lower Respiratory Tract

• Components:

  • Larynx, trachea, bronchi, bronchioles, lungs, and alveoli.

• Alveoli: Sites of gas exchange; tiny air-filled sacs clustered at end of terminal bronchioles.

2. External and Internal Respiration

• External Respiration: Gas exchange between air and blood in the lungs.

• Internal Respiration: Gas exchange between blood and tissues.

3. Dead Space Volume

• Dead Space Volume: Air remaining in airways that does not participate in gas exchange (approx. 150 ml).

4. Respiratory Control Center

• Located in medulla oblongata, establishes basic breathing rhythm.

• Neurons generate impulses every 4

–5 seconds prompting respiratory muscles to contract.

5. What Determines Rate and Depth of Breathing?

• Rate and depth of breathing are regulated to maintain homeostasis of $CO<em>2$, H+, and $O</em>2$ levels.

• Chemical Receptors:

  • Monitor levels of $CO<em>2$, H+, and $O</em>2$ in the blood and cerebrospinal fluid.

  • Increase in $CO<em>2$ (P{CO_2} > 40 mm Hg) results in increased respiratory rate as a primary regulator of respiration under normal conditions.

  • Receptors in aortic and carotid bodies monitor for $O<em>2$ levels, activating breath response to significant drops in $O</em>2$.

6. Movement of Inspiratory Muscles in Inspiration

• Inspiration (Inhale): Diaphragm contracts, lowering pressure in pleural cavity, causing air to enter lungs.

7. Sequence of Air Movement and Site of Gas Exchange

• Sequence of Air Movement:

  • Nose/nasal passages

  • Pharynx

  • Larynx

  • Trachea

  • Bronchi

  • Bronchioles

  • Alveoli

• Site of Gas Exchange: Alveoli

8. Volumes and Capacities

Lung Capacities and Volumes

• Tidal Volume (TV): Volume of air inhaled/exhaled in a single breath (average: 500 ml).

• Dead Space Volume: Air remaining in airways that does not participate in gas exchange (approx. 150 ml).

• Vital Capacity (VC): Maximal volume exhaled after max inhalation.

• Inspiratory Reserve Volume (IRV): Air inhaled beyond tidal volume (avg: 3100 ml male, 1900 ml female).

• Expiratory Reserve Volume (ERV): Air forcibly exhaled beyond tidal volume (avg: 1200 ml male, 700 ml female).

• Residual Volume (RV): Air remaining after forced expiration (avg: 1200 ml male, 1100 ml female).

Respiratory Capacities

• Summation of two or more volumes:

  • Vital Capacity (VC): $VC = TV + IRV + ERV$ .

  • Total Lung Capacity (TLC): $TLC = TV + IRV + ERV + RV$ .

  • Functional Residual Capacity (FRC): $FRC = ERV + RV$ .

  • Inspiratory Capacity (IC): $IC = TV + IRV$ .

9. Form of Carbon Dioxide and Oxygen Transportation in Blood

Oxygen