“THE RESPIRATORY SYSTEM”

HAPChapter 16

Why breathe???

I. Introduction

A. Why Breathe?1. break down nutrients2. produce ATP3. excrete carbon

B. What is the respiratory system?1. Obtaining O2 and removing CO2

II. Organs of the Respiratory System

A. Upper Tract1. nose2. nasal cavity3. paranasal cavity4. pharynx

B. Lower Tract1. larynx2. trachea3. bronchial tree4. lungs

C. The Nose1. comprised of bone and cartilage 2. nostrils (2)

D. The Nasal Cavity1. space behind nose

a. Nasal septum – divides into right and left halves

b. Nasal conchea – bones that give structure

c. Goblet cells – produce mucous -swallow particles (why?)

E. Paranasal Sinuses1. air filled spaces

a. Lighten skullb. Resonant chambers used for voice

F. Pharynx (Throat)1. passageway for air and food2. used for speech3. parts…

a. Nasopharynxb. Oropharynxc. Laryngopharynx

G. Larynx1. enlargement above trachea2. allows air in and out

a. Home of the vocal cords3. 3 cartilages

a. Thyroid – “Adam’s apple”b. Cricoidc. Epiglottic

H. Trachea1. aka windpipe2. flexible tube (2.5 cm diameter / 12.5 cm length)3. splits into r/l bronchi4. goblet cells5. cartilage rings – C-shaped

prevent collapsing

I. Bronchial Tree1. Primary Bronchi

a. Initial split from trachea/5th thoracic vertebra2. Secondary Bronchi3. Tertiary Bronchi4. Bronchioles5. Alveolar ducts6. Alveolar sacs7. Alveoli – tiny air sacs which are surrounded by capillary networks

a. Increase surface areab. 300 million c. 1000 feet2

J. Lungs1. pink, soft, spongy organs…2. found in thoracic cage3. Pleura – sac that lines the lungs…

a. Visceral pleura – inner sac that connects to lungs

b. Parietal pleura – outer sac that holds lungs to the thoracic cavity4. right lobe (3) > left lobe (2)

III. Breathing Mechanism (Boyle’s Law)

A. Def – air into and out of the body.1. Inspiration – inhaling2. Expiration – exhaling

B. Inspiration1. Atmospheric pressure = 760 mm Hg2. How does air get into the lungs?

Diaphragm moves downward / ribs move out

lung volume increases pressure decreases*Result…Outside air moves into the lungs

C. Expiration1. How do we get air out of the lungs?

Elastic recoil of muscular and connective tissue

Diaphragm pushes upwardPressure inside thoracic cavity increasesAir is forced outside of the body

Diaphragm is moving upthus the internal pressure increases causing the air tomove out of the body

D. Respiratory Air Volumes and Capacities tidal volume = amount that enters or leaves lungs

-500 mL inspiratory reserve volume = extra air that can be breathed in

- 3,000 mL (past tidal volume) expiratory reserve volume = extra air that can be breathed out

- 1,100 mL (past tidal volume) residual volume = amount that stays in the lungs permanently

- 1,200 mL total lung capacity = total amount of air that could be found in lungs. -5,800 mL vital capacity = maximum amount a person can exhale after taking in a full breath.

-4,600 mL

Respiratory Volumes and Capacities

IV. Control of Breathing

A. The Respiratory Center (involuntary and voluntary)1. Location – Brainstem

a. Pons b. Medulla Oblongata

2. Special Areasa. Medullary Rhythmicity Area dorsal respiratory group -basic inspiration rhythm (at rest) -send signals to diaphragm and other small muscles ventral respiratory group -dormant at resting levels -activated during forceful breathing -send impulse to larger muscles used in breathing

b. Pneumotaxic Area transmit impulses that inhibit

inspiratory bursts from the dorsal respiratory group

controls the overall breathing rate-when transmitting = slow

breathing-when not transmitting = fast

breathing

B. Factors that Affect Breathing1. High CO2 levels (primary)

2. High H+ ion levels3. Low blood O2 levels (minor)

4. Emotions (fear, pain, stress)

V. Alveolar Gas Exhange

A. Respiratory Membrane1. Simple Squamous Epithelial Cells2. Covered in a capillary network3. O2 and CO2 easily exchanged

B. Diffusion (HL)1. Partial pressure – amount of pressure for each gas according to concentration.

Gas Lung (alveoli) Capillary

O2 104 mmHg 40 mmHg

CO2 40 mmHg 45 mmHg

VI. Gas Transport

A. Oxygen Transport1. hemoglobin

a. 98% of all O2

b. Forms oxyhemoglobin-bond is unstable-O2 is released

-O2 diffuses into nearby cells

c. Factors which cause oxyhemoglobin to release O2

-CO2 levels, acids, increase in blood temp

*Explains why working muscles get more O2

Hypoxia – O2 deficiency

B. CO2 Transport (3 methods)

1. CO2 dissolved in plasma

a. Based on partial pressureb. Approx. 7%

2. Part of a compound formed with hemoglobina. Binds with globulin (-NH2)

-carbaminohemoglobinb. Approx. 23%

3. Converted to Bicarbonate ion (HCO3-)

a. CO2 + H2O H2CO3 (carbonic acid)

-carbonic anhydrase (enzyme)b. Approx. 70%