Porth - Respiratory Function

Question 1

Primary Function of Respiratory System

Answer 1

Gas Exchange

• O2 from the air transferred into the blood
• CO2 from blood eliminated into atmosphere

Question 2

2 Parts of the Respiratory System (Functionally)

Answer 2

1. Conducting airways:
   
   1. Air moves as it passes btwn atmosphere and lungs
   2. Filters, humidifies, & warms air
2. Respiratory Tissues:
   
   1. . Gas exchange occurs here in the lungs

Question 3

Mediastinum

Answer 3

• “The Space Between the Lungs”
• Separates lungs

Question 4

Conducting Airway Structures

Answer 4

• Nasal passages
• Mouth
• Pharynx
• Larynx
• Trachea
• Bronchi
• Bronchioles

Question 5

The Conducting Airways Wall has 3 components… What are they?

Answer 5

• Mucosal Lining (epithelial & conductive tissue)
• Smooth Muscle Layer
• Supporting Connective Tissue Layer

–Lined with ciliated pseudostratified columnar epithelium (provides moisture)

—Cigarette smoking slows down/paralyzes cilia’s motility: creates particle accumulation in lungs; decreases defenses

Question 6

Ventilation

Answer 6

Movement of gases into and out of the lungs through a system of open airways & along a pressure gradient resulting from a change in chest volume.

Question 7

Perfusion

Answer 7

Movement of blood through the lungs

Question 8

Innvervation of the Lung

Answer 8

• Sympathetic & Parasympathetic NS divisions
• Parasympathetic = Vagal Nerves
• Sympathetic = Upper Thoracic & Cervical Ganglia

– Together, these guys form the Pulmonary Plexuses

Question 9

Nervous System-wise, what do you NOT find in the Lungs?

Answer 9

• NO Voluntary Motor Innervation
• NO Pain Fibers
  
  • Pain fibers are found in the pleura

Question 10

Parasympathetic NS & Stimulation

Answer 10

• Airway constriction
• Blood Vessel Dilation
• Increased Glandular Secretion
• Excitatory/Cholinergic motor neurons are located here & respond to ACH

Question 11

The smooth muscle of the lung under Normal Resting Conditions is…

Answer 11

Slight constricted

Due to parasympathetic stimulation

Question 12

Sympathetic NS & Stimulation

Answer 12

• Airway Dilation
• Blood Vessel Constriction
• Inhibition of glandular secretion

Question 13

Pleura

Answer 13

• Thin, transparent, double-layered serous membrane.
• Lines thoracic cavity
• Encases Lungs
• Thin flim of serous fluid separates the layers

Question 14

Pleural Cavity

Answer 14

• Potential space in which serous fluid or inflammatory exudate can accumulate
• *Pleural effusion = Abnormal collection of fluid in the pleural cavity*

Question 16

Partial Pressure

Answer 16

Pressure exerted by a single gas in a mixture. Denoted by a “P”.

Question 17

A little bit of physics…

Answer 17

• Air moves between the atmosphere and lungs b/c of a pressure different (or gradient).
  
  • Inspiration = air moves into lungs as size of chest cavity increases
  • Expiration = air moves out of lungs as size of chest cavity decreases
    
    • Movement is from the area of greater pressure to less.

Question 18

Minute Volume

Answer 18

• The amount of air that is exchanged each minute.
  
  • Determined by the metabolic needs
• Tidal Volume x Respiratory Rate

Question 19

What causes the negative pressure in the Pleural Cavity?

Answer 19

• Opposing forces of the chest wall and lungs

Question 20

During Inspiration….

Answer 20

• Chest cavity size increases
• Intrathoracic pressure decreases (becomes more negative)
• Diaphragm contracts
• Air is brought into Lungs!

Question 21

During Expiration…

Answer 21

• Chest wall & lung structures recoil
• Diaphragm relaxes
• Chest cavity size decreases
• Pressure inside the cavity increases
• Expiration is largely passive

Question 22

Diaphragm

Answer 22

The Principle muscle of inspiration!

• During normal levels of inspiration, the diaphragm moves ~1cm.
• Innvervated by the Phrenic Nerve (C3,C4,C5)

Question 23

Lung Compliance

Answer 23

• The ease with which the lungs can be inflated
• “Measure of change in lung volume that occurs with a change in intrapulmonary pressure.”

Question 24

Lung Diseases that mess with the elasticity of the Lungs

Answer 24

• Interstitial Lung Disease
• Pulmonary Fibrosis
  
  • Elastin fibers replaced by collagen
• Pulmonary congestion
• PE
  
  • Increase water content in lung, thus decreasing compliance

Question 25

Elastic Recoil

Answer 25

• Ability of the lung to recoil to their original position after being stretched
• Emphysema overstretches lung tissues
  • Easy in inflate
  • Harder to deflate