Pulmo: Anatomy and Physiology

• Ventilation and Perfusion

• Respiration

• Transport of oxygen and carbon dioxide

• Diffusion of oxygen and carbon dioxide

functions of the lungs.

Ventilation

act of moving air in and out of the lungs, inhale or exhale, inspire or expire.

Boyle’s Law

- states that “as we inhale, air goes inside the lungs; as we exhale, air goes outside the lungs”

- law that explains ventilation

Perfusion

pulmonary blood flow to the lungs, essential for gas exchange.

0.8 or 80%

normal ventilation to perfusion ratio.

Base

in the lungs, this is where perfusion is at the greatest.

Respiration

refers to the gas exchange of oxygen and carbon dioxide, which occurs in the lungs and at the tissue level.

External Respiration

gas exchange happens between the alveoli and capillaries.

Internal Respiration

gas exchange happens in between the capillaries and tissues.

Passive Diffusion

type of diffusion that is utilized in the exchange of oxygen and carbon dioxide.

• Nose

• Pharnyx

• Larynx

components of the upper respiratory system.

Nose

large cavity with a mucosal surface area that filters and warms/humidifies air.

Vibrassae

hair inside the nose that trap foreign particles.

• Nasopharynx

• Oropharynx

• Laryngopharynx

three parts of the pharynx.

Larynx

for voice or sound production, ensures that air will pass through the trachea.

Epiglottis

leaflet cartilage that guards the airways.

• Thyroid (1)

• Cricoid (1)

• Arytenoid (2)

• Corniculate (2)

• Cuneiform (2)

• Epiglottis (1)

cartilages inside the larynx.

• Trachea

• Main bronchi

• Lobar bronchi

• Segmental bronchi

• Terminal bronchioles

• Respiratory bronchioles

• Alveolar ducts

• Alveolar sacs

• Alveolii

• Capillaries

components of the lower respiratory tract.

23 generations

number of generations in the lungs.

Trachea

most common site of intubation.

Larynx

most common site of emergency intubation.

Carina

point where the trachea bifurcates (divides) into the left and right main bronchi, located at the level of the 4th rib anteriorly and the T4 vertebra posteriorly.

Right Lung

common site of aspiration pneumonia.

Right Main Bronchus

resting place of large aspirated objects.

Lobar Bronchi

resting place of small aspirated objects.

300 million alveoli

number of allveoli in lungs.

Conduction Zone

zone which is composed of trachea, main bronchi, lobar bronchi, segmental bronchi, and terminal bronchi.

Respiratory Zone

- zone which is composed of respiratory bronchioles, alveolar ducts, alveolar sacs, alveoli, and capillaries

- site of gas exchange

- acinus

- Right Lung

• Superior

• Middle

• Inferior

- Left Lung

• Superior

• Inferior

lobes of the lungs.

Lingula

tongue shaped structure

Visceral Pleura

- membrane that directly covers the lungs, including the fissure lines

- sensitive to stretch

Parietal Pleura

- membrane covering the thoracic wall

- sensitive to pain

Pleural Space

space betwen visceral and parietal pleura.

-4 mmHg

normal pressure in pleural space.

Pleural Fluid

fluid inside the pleural space that lubricates the pleurae and has shock absorption properties.

Type 1 Pneumonocytes

flat cells inside the lung that lines the alveoli.

Type 2 Pneumonocytes

cells that synthesizes surfectant that reduces the surface tension of lungs to prevent collapse.

Respiratory Distress Syndrome

- newborn condition wherein there is a decrease in surfectant resulting to small alveoli collapse

- hyaline membrane disease

• Anterior: sternum

• Posterior: thoracic vertebrae (T1-T12)

• Superior: thoracic outlet

• Inferior: diaphragm

• Lateral: ribs

boundaries of the thorax.

Pump Handle Motion

thoracic cage mechanism, which involves the sternum and ribs 1-6 and increases the anteroposterior diameter of the thoracic wall.

Bucket Handle Motion

thoracic cage mechanism, which involves the ribs 7-10 and increases the lateral diameter of the thoracic wall.

Caliper Motion

thoracic cage mechanism which involves ribs 8-12 wherein the ribs move laterally to increase the transverse diameter of the thoracic cavity during inspiration.

• Inhalation: downward and outward

• Exhalation: upward and inward

movement of the diaphragm during piston action.

• Diaphragm

• External intercostals

muscles for relaxed inspiration.

• SCM

• Upper trapezius

• Pectoralis major and mino

• Anterior, middle, and posterior scalene

• Serratus anterior and superior division of serratus posterior

muscles for forced expiration.

• Abdominals

• Serratus Posterior (inferior division)

• Internal intercos

muscles for forced expiration.

Phrenic Nerve (C3-C5)

innervation of the diaphragm.

• Pons

• Medulla Oblongata (automatic)

part of brainstem which is responsible for the control of respiration.

• Dorsal respiratory group

• Vental respiratory group

• Pneumotaxic center

• Apneustic center

• Chemoreceptors

controls of respiration.

Dorsal Respiratory Group

- responsible for inspiration

- location: dorsal medulla/nucleus tractus solitarius

• Inhale - 2 secs on

• Exhale - 3 secs off

inspiratory ramp signal.

Ventral Respiratory Group

- responsible for expiration and inspiration

- location: ventrolateral medulla/nucleus ambiguus

Pneumotaxic Center

- limits inspiration by switching off the inspiratory ramp signal, controls rate and depth of breathing

- location: superior pons/ nucleus parabrachialis

Apneustic Center

- prevents the switching off of inspiratory ramp signal

- location: inferior pons

Central Chemoreceptors

- location: ventral medulla

- stimulus: increase hydrogen ions

- effect: hyperventilation

Peripheral Chemoreceptors

- location: carotid and aortic bodies

- stimulus: decrease partial pressure of oxygen and pH and increase partial pressure of carbon dioxide

- effect: hyperventilation

7.35-7.45

normal pH.

35-45 mmHg

normal PaCO2.

22-26 mEq/L

normal HCO3.

80-100 mmHg

normal PaO2.

95-100%

normal SaO2

• pH is inversely related to PaCO2

• pH is directly related to HCO3

relationship of pH to PaCO2 and HCO3

• Dizziness

• Early tetany

• Numbness

• Tingling

• Syncope

signs and symptoms of respiratory alkalosis.

Early

• Headache

• Anxiety

• Restlessness

• Dyspnea

Late

• Disorientation

• Somnolence

• Coma

signs and symptoms of respiratory acidosis.

• Weakness

• Early tetany

• Mental dullness

• Increase DTR

• Muscle twitching

signs and symptoms of metabolic alkalosis.

• Nausea

• Lethargy

• Coma

• (+) Kussmaul’s breathing

signs and symptoms of metabolic acidosis.

• COPD

• Atelectasis

• Respiratory failure

• Pneumonia

• Asthma

causes of respiratory acidosis.

• Hypoxemia

• Hyperventilation

• Ventilator

• Pain

causes of respiratory alkalosis.

• DM ketoacidosis

• Diarrehea

• Renal failure

causes of metabolic acidosis.

• Vomiting

• Antacids

• Nasogastric sunctioning

• Diuretics

• Excessive bicarbonate ingestion

causes of metabolic alkalosis.

• ↑ hydrogen ions

• ↑ CO2

• ↑ temp

• ↑ 2,3 diphosphoglycerate

• ↓ pH

• exercise

causes of a right shift in the oxygen-hemoglobin dissociation curve.

• ↓ hydrogen ions

• ↓ CO2

• ↓ temp

• ↓ 2,3 diphosphoglycerate

• ↑ pH

• ↑ (+) fetal Hb

causes of a left shift in the oxygen-hemoglobin dissociation curve.

Bohr Effect

↑ binding of carbon dioxide with hemoglonin will displace oxygen therefore promoting oxygen transport

Haldane Effect

↑ binding of oxygen with hemoglonin will displace carbon dioxide therefore promoting carbon dioxide transport

Dead Space Air

- air found inside the lungs but is not used during gas exchange

- N: 150 mL

- types:

• anatomic

• alveolar

Spirometer

device used for measurement of lung volume and capacities.

• Helium or nitrogen washout

• Body plethysmography

used to measure RV, FRC, and TLC

Tidal Volume

amount or volume of air inspired or expired with each normal breath.

Inspiratory Reserve Volume

amount of air that can be inspired in after a normal/maximal inspiration

Expiratory Reserve Volume

amount of air that can be expired out after a normal/maximal expiration.

500 mL

normal value of TV

3000 mL

normal value of IRV

1000 mL

normal value of ERV

Residual Volume

amount of air left inside the lungs after a forceful/maximal expiration

1500 mL

normal value of RV.

Inspiratory Capacity

amount of air that can be inspired in after a normal expiration.

3500 mL

normal value of IC.

Functional Residual Capacity

amount of air left inside the lungs after a normal expiration.

2500 mL

normal value of FRC.

Vital Capacity

amount or volume of air that can be maximall expired after a maximal inspiration.

4500 mL

normal value of VC.

Total Lung Capacity

amount of air that can be contained inside the lungs after a maximal inspiration.

6000 mL

normal valie of TLC.