Pulmonary A & P

Why does the left lung only have 2 lobes?

To accommodate the heart on the left side of the rib cage.

What is the purpose of cilia in the respiratory tract?

To trap and sweep up mucous and debris up toward the larger airways for expulsion.

How does the epiglottis prevent aspiration?

The epiglottis acts as a flap that covers the trachea during swallowing, preventing food and liquids from entering the airway.

Upper respiratory tract

The part of the respiratory system that includes the nasal cavity, pharynx, and larynx, responsible for filtering, humidifying, and warming the air we breathe.

Lower respiratory tract

The part of the respiratory system that includes the trachea, bronchi, and lungs, responsible for gas exchange.

Where does gas exchange take place?

Alveoli

Respiration

The process of inhaling oxygen and exhaling carbon dioxide.

Ventilation

The process of moving air in and out of the lungs, allowing for gas exchange to occur.

Inhalation

The act of taking air into the lungs through the contraction of the diaphragm and intercostal muscles. Increased volume in the thoracic cavity decreases pressure, allowing air to flow in.

Exhalation

The act of expelling air from the lungs through the relaxation of the diaphragm and intercostal muscles. Decreased volume in the thoracic cavity increased pressure, forcing air out.

Bucket handle movement

A mechanism of rib movement during respiration where the lower ribs elevate and move laterally.

Pump handle movement

A mechanism of rib movement during respiration where the upper ribs move anteriorly and superiorly.

Primary muscles of inspirtion

Diaphragm and external intercostals.

Accessory muscles of inspiration

SCM, scalenes, and pectoralis minor.

How does the SCM and scalenes assist during inspiration?

The SCM will lift the clavicle and sternum, the scalenes will lift the first and second ribs.

What might be observed with excessive use of accessory muscles during breathing?

Visible neck muscle strain, chest wall retractions, and increased respiratory rate.

Involuntary control of breathing

is regulated by the pons (brainstem), which monitors carbon dioxide and oxygen levels in the blood, adjusting the rate and depth of respiration accordingly.

What nerve innervates the diaphragm? At what level?

The phrenic nerve, originating from cervical levels C3 to C5.

What happens to RR when SpO2 drops?

Respiratory rate increases to compensate for low oxygen levels in the blood.

Tidal Volume

air that is moved in or out of the lungs during a normal breath. It typically averages about 500 milliliters in adults.

Inspiratory Reserve Volume

extra air that can be inspired beyond normal inspiration. It typically averages about 3100 milliliters in adults.

Expiratory Reserve Volume

extra air that can be exhaled beyond normal expiration. It typically averages about 1200 milliliters in adults.

Residual Volume

air that is left in the lungs after maximal exhalation, preventing lung collapse. It typically averages about 1200 milliliters in adults.

Total Lung Capacity

total amount of air in lungs after max inspiration. Normal = 6L

IRV+TV+ERV+RV

Vital Capacity

max amount of air expired following a max inspiration. Normal = 4800 ml

IRV+TV+ERV

Functional Residual Capacity

amount of air remaining in the lungs after normal exhalation. Normal = 2400ml

ERV+RV

Forced Vital Capacity

amount of air that can be exhaled during maxed forced expiration effort.

Forced Expiratory Volume

amount of air exhaled forcefully in 1, 2, 0r 3 seconds

FEV1/FVC Ratio

Normal = 75 to 80%
Obstructive Lung Disease = < 70%
Restrictive Lung Disease = > 80%

Minute Ventilation

amount of air breathed in or out per minute. Average = 6L/min

Ventilation Perfusion

Imaging test that uses a ventilation scan to measure air flow and a perfusion scan to measure blood flow. Often used to diagnose pulmonary embolism

Arterial Blood Gases

Gold standard for evaluating pH, ventilation, and oxygenation

pH

7.35-7.45

PaCO2

35-45 mmHg

PaO2

80-100 mmHg

HCO3

22-26 mEq/L

SpO2

95-99%

Respiratory Acidosis

A condition characterized by an excess of carbon dioxide in the bloodstream due to inadequate ventilation, leading to a decrease in blood pH; pH < 7.35

Respiratory Alkalosis

A condition characterized by a deficit of carbon dioxide in the bloodstream due to excessive ventilation, leading to an increase in blood pH; pH > 7.45.