Anatomy Ch 23

• 1. Gas exchange - O₂ in (used for ATP porduction)
• - - CO₂ out - waste product of the body
• 2. pH regulation
• 3. Temperature & H₂O regulation (traps water)
• 4. Small recaptors
• 5. Immune - mucus is a 1st line of defense - filter/ trap/ removal
• 6. Sound production

• Glucose (C₆H₁₂O₆) + O₂ → CO₂ + H₂O + energy
• 36 ADP + 36 P + energy → 36 ATP

• Structurally:
• 1. Upper respiratory system - nose & pharynx
• 2. Lower respiratory system - larynx, trachea, bronchi, lungs, pleural cavities

• Functionally:
• 1. Condicting - nose, pharynx, larynx, trachea, 2 bronchi, bronchioles, terminal bronchioles

2. Respiratory (gas exchange) - respiratory bronchioles, alveolar ducts, alveloar sacs, alveoli

• External nose:
• 1. bone/cartilage - support
• 2. muscle/ skin - cover
• 3. mucous membrane - lining

• a. Three cartilages
• 1. septal - middle/ midline (x1)
• 2. lateral - each side of septal (x2)
• 3. alar - walls of nostrils (x2)

• Internal anatomy:
• 1. Choanae - internal nares - 2 openings that communicate with the nasopharynx
• 2. Ducts - form paranasal sinuses (mucus) and nosolacrimal (tears) open into the internal nose
• 3. Nasal cavity - space within internal nose
• 4. Nasal chonchae - turbinates - superior, middle, inferior
• 5. Meatuses - passages between the turbinates - superior, middle, inferior

b. mucose is pseudostratified ciliated epitherial with goblet cells for mucous production

• 1. Warm, moisten, and filter air
• 2. Smell - via receptors
• 3. Modifies speech - via resonance

• The pharinx runs from the internal nares to the cricoid cartilage.
• 1. nasopharynx - superior portion -internal nares → soft palate & connets to eustachian tubes = made of pseudostratified ciliated columnar mucosa w/ goblet cells

2. oropharynx - soft palate → hyoid bone = made of stratified squamous mucosa (non keritinized) to protect from abradion

3. laringopharynx (hypopharynx) - hyoid bone → (anterior) larynx & (posterior) esophagus = made of stratified squamous (nonkeratinized) mucosa

• Structure:
• skeletal muscle lined with mucosa

• Function:
• passageway for food and air
• resonating cavity
• immune function - pharyngeal tonsils (adenoids) are located here

• Eustachien tube:
• The nasopharynx excanges air with the eustachien tubes to equalize pressure between the pharynx and the middle ear.

• a. The epiglottis keep food and liquid from entering the larynx and going into the lungs.
• b. Epiglottis is made of elastic cartilage covered with epithelial tissue

• c. 9 cartilages of the larynx:
• 1. Thyroid - adams apple- anterior & largest
• 2. Epiglottis - covers larynx when swallowing
• 3. Cricoid - inferior end of pharynx - inferiorly attached to thyroid cartilage by crocithyroid ligament - just superior to trachea
• 4. Arytenoids (2) - posterior, superior border of cricoid cartilage - attached to true vocal cords - form synovial joints with cricoid cartilage - wide range of mobility
• 5. Corniculate (2) - horns on the arytenoids that support the epiglottis
• 6. Cuneiform - club like - anterior to the corniculate cartilages - support the vocal folds and epiglottis

d. Glottis - true vocal cords (folds of mucous membrane). The ventricular folds are also known as the false vocal cords - They are superior to the true vocal cords.

e. Cricothyroid membrane - used for making an emergency airway in the case of blockage - tracheotomy

f. Arytenoid cartilages are inportant for vocal production becuase they are attached to the vocal ligaments (true vocal cords) and move as the vocal ligaments open and close.

g. A tracheostomy is inserted into the trachea inferior to the cricoid cartilage.

Sound is produced when air is directed against the vocal cords and they vibriate and they resonate by creating sounds waves in the larynx, nose, and mouth.

• a. Pitch is controlled by the amound of tension on the vocal cords.
• Sound = vibration
• Pitch = tension
• Thickness = deeper voice

b. Resonating structures = pharynx, mouth, nasal cavity, and sinuses

• c. The cricoarytenoid muscles pivot the arytenoid cartilages to change the position of the vocal ligaments
• lateral cricoarytenoids (contraction) = tighten = sound
• posterior cricoarytenoids (contraction) = loosen - cords move apart

a. The trachea is the windspipe - its function is to conduct gases

• b. Runs from larynx → T5 (splits into R & L bronchi)
• anterior to the esophagus

c. Trachael cartilages - C shaleped hialine cartilage connected by dense CT - semirigid support so trachea does not collapse

• d. Walls of Trachea
• - - 1. mucosa (deep) - pseudostratified ciliated collumnar with goble cells (mucus) - underlying layer of lamina propria (elastic and reticular fibers)
• - - 2. submucosa - aerolar CT with seromuccus glands
• - - 3. hyaline cartilage
• - - 4. adventitia (areolar CT)
• - - 5. Open part of C contains trachealis muscle - smooth (involuntary) muscle

e. Lamina propria & trachealis muscle - allows traches to expand and contract to control airflow

• a. Primary bronchi - 2 R & L - go to lungs
• b. Seconday bronchi - 5 - go to each lobe (3 on R; 2 on L) "lobular bronchi"
• c. Tertiary bronchi - 10/lung - go to each bronchopulmonary segment "segmental bronchi"
• d. Bronchioles → terminal bronchioles that supply lobules (many)

• b. Smooth muscle line entire bronchial tree -
• - - sympathetic (EPI/ NOR) = bronchodilation = more air
• - - para (ACh) = brochoconstriction (also caused by asthma)

c. Carina - last trachael ring where R & L bronchi begins - most sensitive area for triggering cough reflex

d. The R primary bronchi is move vertial, shorter, and wider than L - easier for stuff to get into

Lungs are separated so that if one is damaged or collapses the other is still functioning.

• Pleura = sirus membrane of the pleural cavity - also called the mesotheilum
• 1. parietal pleura - lines the wall of the thoracic cavity
• 2. visceral pleura - covers the lungs
• 3. pleural cavity - filled with pleural fluid to reduce friction and provide surface tension (hold pleural layers together)

Pleural effusion = excess fluid in the pleural space - may cause lung collapse

pneumothorax = air in the pleural cavity - may cause lung to collapse

hemothorax = blood in the pleural cavity - may cause lung collapse

atelectasis = collapse of all or part of a lung

thoracentesis = remove fluid from pleural cavity - can be diagnostic or theraputic (removal of extra liquid) - insert a needle at the seventh intercoastal space

• Yes. The parietal pleura adheres to the diaphram. This is an important part of ventillation.
• 1. As the diapharm contracts and flattens the thoracic cavity volume increaded.
• 2. The diaphram pulls the parietal pleura - which pulls the viseral pleura and the lungs - expanding the lungs
• 3. The lung volume ↑ so (intrapulmonic) pressure ↓ to 758 mmHg - below atmospheric pressure - air moves into lung.

• Lungs end at T10
• pleura ends at T12
• The bronchi, blood vessels, lympatics, and nerves enter the lungs at the Hilum (called the root) - entering structures are covered with pleura

1. Main function of alveoli = gas exchange - Over 300 million alveoli

• 2. alveolar air space → blood plasma (4 layers)=
• - - a. alveolar wall (Type I & II alveolar cells, mphages)
• - - b. epithelial basement membrane
• - - c. capillary basement membrane - fused to epithelial basement membrane
• - - d. capillary endothelium

3. Each alveoli is surrounded by a capillary bed.

• 4.
• 1. Type I alveolar cells - most numerous- simple squamous - used for gast exchange
• 2. Type II alveolar cells - cuboidal w/microvilli - make alveolar fluid (surfaciant)
• 3. Alveolar macrophages (dust cells) - phagocytes
• 4. Fibroblasts - make elastic and reticular fibers (for expansion/ contraction

Ventilation = mechanical breathing - movement of air in/ out of the lungs

• Respiration = gas exchange
• 1. External respiration (pulmonary respiration) - gas exchange between alveoli and pulmonary capillaries

2. Internal respiration (systemic respiration) - gas exchange between systemic capillaries & tissue cells

1. Boyle's Law = Pressure is inversely related to volume. Inspiration and Expiration are driven by differences in pressure. Gas flows from high → low pressure.

2. When the diaphram contracts (flattens) the volume in the thoracic cavity ↑. Pressure in the cavity ↓ to 758 mmHg. Intrathoracic (intrapleural) pressure ↓ to 756 mmHg. Atmospheric pressure is 760 mmHg so air flows down the pressure gradient into the lungs. This is known as inspiration or inhalation. (75% of ↑ from diaphram). The diaphram is innervated by the phrenic nerve which comes off the spinal cord at C3, C4, & C%.

• 3. The external intercoastal muscles contract and cause the rib cage to move superiorly and anteriorly (25% of volume increase).
• The internal intercoastal contract on forced exhalation and move the inferior ribs downward and compresses the abdominal viscera

4. Inhalation uses ATP (muscles contract) however exhalation is a passive process and does not use ATP normally.

• 5. Atmospheric pressure = 760 mmHg
• - Intrathoracic pressure = 756 mmHg
• - - Inhallation - Interpulmonic pressure = 758mmHg & intrathoracic (intrpleural) is 754 mmHg
• - - Exhalaiton - Interpulmonic pressure = 762 mmHg & intrathoracic = 758 mmHg

• 6. Accessory muscles of inspiration = scalenes, sternocledomastoid, serratus, pectoralis minor
• - Accessory mucles of expiration - internal intercoastals and abdominal muscles

Dyspnea = difficulty breathing

Apnes = no breathing

Hyperventillation = fast breathing

1. Inspiration is an active process and uses ATP. Expiration is a passive provess and does not usually use ATP. Forced exhalation requires contraction of muscles and thus uses ATP.

2. The diaphram and external intercoastals relax on expiration. The lamina propria recoils (elastic fibers)

3. Abdominal pressure ↑ during inhalation and ↓ during exhalation (unless forced exhalation)

Sufactant is a phospholipid & lipoprotein mixture that is found in the alveoli. It is made by Type II alveolar cells as part of the alveolar fluid.

• Sufactant reduces the surface tension of H₂O by breaking the hydrogen bonds.
• Surface tension pulls on alveoli and makes them assume their smallest sphere shape - surface tension must be overcome during inhalation but provides 2/3 of the recoil during exhalation.

Lowering the surface tension of the alveoli will make it easier to breath.

Compliance is how much effort is needed to stretch the lungs and chest wall. Determined by elasticity and surface tension.

• high compliance = easy breathing
• low compliance = harder to breathe

• Airflow depends on both pressure difference and resistance.
• ↓ diameter = ↑ resistance
• ↑ diameter = ↓ resistance (more space to flow thorugh)
• resistance ↑ during exhalation as bronchioles get smaller.

• V_t (tidal volume) = amount of air moved into or out of the lungs in one breath.
• Normal tidal volume = 500-700 cc in adults
• 10cc/ kg of weight

• Respiratory rate = breaths/ minute
• normal value = 12 -20 / min

• Minuter ventilation (MV) = volume of air moved each minute
• V_t x respiratory rate = MV
• 12/ min x 500cc = 6 L (adult female)

• Respiratory zone = gas exchange system - respiratory brochioles, alveolar ducts, alveolar sacs, alveoli
• 70% of V_t make it here

Anatomic dead zone = 30% V_t - non-exchanging structures (nose, pharynx, larynx, trachea, bronchi, bronchioles, terminal bronchioles.

Alveolar ventilation rate = volume of air that reaches respiratory zone per min (cc/min)

Spirometer = device that measures volume of air exchanged during breathing and respiratory rate.

• a. V_t = vol air moved per breath
• b. IRV = air vol of deep breath (beyond V_t)
• c. IC = V_t + IRV

• d. ERV = forced expiration (beyond V_t)
• e. RV = connot be expired - keep alveoli from collapsing - can't be measured on spirogram
• f. FRV = RV + ERV - ↓ if diaphram is pushed up (pregnancy)

• g. VC = ERV + V_t + IRV - all values except RV
• h. TLC = VC + RV - all lung volumes

* capacity are combinations of values

• Simple diffusion (passive) down the gradient
• Governed by Dalton's Law and Henry's Law

Dalton's Law states that each gas in a mixture exerts its own pressure as if no other gases were present.

Partial pressure is the pressure of a specific gas in a mixture. Total pressure is all partial pressures together

Gas will move down its concentration gradient from areas with a high partial pressure to low pp.

• Air:
• N₂ = 78%
• O₂ = 21%
• H₂0 = <1%
• CO₂ = <1%

Atmosheric pressure = 760 mmHg

Henry's Law = Amount of gas that will dissolve in a liquid is proportional to the partial pressure of that gas and the solubility of that gas in the solution (plasma).

↑ partial p + ↑ solubility = ↑ amount of gas dissolved in plasma

• Solubility of gas in plasma:
• 1. CO₂ (24x more soluble than O₂)
• 2. O₂
• 3. N₂ (insoluble at atmospheric P)

atmospheric P ↑ = ↑ all partial Ps in gas mixture

Nitrogen narcosis = ↑ atmospheric P (under water) = ↑ P_N2 = ↑ solubility in plasma. High N₂ in plasma results in delirium (giddiness like alcohol intoxication)

External respiration is pulmonary (lungs) gas exchange of O₂ (into venous blood) and CO₂ (out of venous blood).

Internal respiration - systemic gas exchange between systemic capillaries and interstitial fluid (moves into cell)

• pO₂ is 105 mm in alveoli & 40 mm in pulmonary capillaries (veins)
• O2 down pressure gradient from alveoli → capillaries

pCO2 is 45 mm in pulmonary capillaries & 40 in alveoli - down pressure gradient

• Normal pO₂ ~100 mmHg
• Normal CO₂ ~ 35 - 45 mmHg

pO2 = 105mm (capillaries) → 40 mm (Interstitial fluid)pCO2 = 45mm (IF) → 40 (capillaries)

Cells extract 25% of avilable O₂

Venous blood still has 75% of atrial blood O₂ content.

• 1. Partial pressure difference of the gases (gradients)
• 2. Surface area available for gas exchange
• 3. Diffusion distance - (increases w/ pulmonary edema)
• 4. Molecular weight and solubility -
• ↑ solubility = ↑ rate of diffusion
• ↑ molecular wt. of gas = ↑ rate of dissusion

• plasma- O₂ = 1.5% CO₂ = 7%
• Hgb - O₂ = 98.5% CO₂ = 23%

70% CO₂ is transported in RBCs in the form of HCO^_3-

• Oxyhemoglobin = O₂ bound to heme units on Hgb
• Hbg + O₂ ↔ HgbO₂ (oxyhemoglobin)
• reversible reaction

• Hemoglobin = globin (protein) made of 4 polypeptide chains. 1 Heme group (ringlike nonprotien pigment w/ iron ion at the center) is attached to each of these. Each iron ion bind to 1 molecule O₂
• 4 globins = 4 hemes = 4 O₂ / Hgb molecule

• Oxy-hemoglobin curve shows how much O₂ binds to Hgb at any given partial pressure.
• ↑ pO₂ = ↑ oxyhemoglobin formed
• ↓ p O₂ = ↑ O₂ released from Hgb
• The curve facilitates ↑ rate of O₂ released from Hgb as O₂ in plasma drops (straight line graph wouldn't represent that)

1. pO₂ decrease -shift to right - most important factor

• 2. pH- - Bohr Effect - ↓pH (acidic) → O₂ release
• - - Hypoxic tissue generate acid (H⁺) which bind to a.a. on Hgb - changes the 3-D shape of Hgb = releases more O_2.
• Acid = shift to right (more O₂) released at any pO₂

• 3. pCO₂ - increased pCO₂ = shift to right (CO₂ can bind to a.a & changes shape also)
• CO₂ + H₂O ↔ H₂CO₃ (carbonic acid) ↔ H⁺ + HCO^3-

• 4. Temperature - Increased Temp = Shift to right - ↑ temp = ↑ metabolic demand = ↑ O₂ consumes
• temp decreases = less O₂ released

• 5. BPG : increased 2,3 BPG = shirt to right
• BPG is byproduct of glycolysis
• 1) glucose → (2)2,3 BPG's → (2) pyruvic acids
• BPGs found in RBCs - a BPG concentration ↑ it binds to Hgb & changes its shape = Hgb releases more O₂.
• (increased levels of BPGs in hypermetabolic states and high altitude)

*Fetal Hgb - shift to left - higher affinty

Most CO₂ (70%) is carried in RBCs as HCO^3-. It is converted to carbonic acid (H₂CO₃) and then to bicarbonate ions (HCO^3-) in RBCs by carbonic anhydrase.

• In the lung CO₂ is released from venous blood
• - CO₂ dissolved in plasma is released
• - CO₂ bound to Hgb is released
• - HCO_3- has to be converted back to CO₂ (in RBC) and released

• CO₂→ (H₂CO₃→ HCO_3-→ H₂CO₃)→ CO₂
• - uses carbonic amhydrase in RBC

When low O₂ - oxy-Hgb can bind both CO₂ and H⁺ beter to correct aciddosis (Hgb = buffer) (H⁺ displaces O₂ in acidosis.

H⁺ HgbO₂ ↔ H⁺Hgb + O₂

• Respiration is controlled by the respiratory center in the brain stem:
• 1. Medulla oblongata -
• - the