Functional Anatomy & Histology

Question 1

Structures of Upper and Lower Respiratory tract

Answer 1

• if they aren’t apart of gas exchange then they are dead space-conduct/condition air
  
  • alveoli-gas exchange only
• Sinuses aren’t part of the respiratory system
• Conduction: conduct air from the aupper respiratory tract to alveoli
• dead space=no gas exchange, just transport
• Upper respiratory tract:
  
  • Nasal cavity
  • Oral cavity
  • Pharynx
  • Larynx
  • Sinuses
• Lower Respiratory tract
  
  • Trachea
  • Bronchi
  • Bronchioles
  • Alveoli

Question 2

Nose

Answer 2

Upper Respiratory Tract: Conduct/condition air

• 15,000 L air/day
• Volume of nasal passages: 20mL
• 50% of airflow resistance
• Air is warmed and humidified as it flows around turbinates (highly vascularized)
• large particles filtered by vibrissae (nose hair)

Question 3

Larynx

Answer 3

Upper Respiratory Tract-Conduct/condition air

• swelling can block flow

Question 4

Nasal Cavity:

Answer 4

• Superior Turbinate:
  
  • olfactory epithelium contains sensory cells that are stimulated when molecules become trapped in mucus

Question 5

Respiratory system: Thoracic structures

Answer 5

• Pleural space
  
  • thin, fluid filled space
  • seperates the lungs from the chest
  • allows the lungs to slide along the chest wall with very little friction
• Pressure changes of pleural space
  
  • caused by movement of the chest wall
  • pressure changes are transmitted to the lungs, deforming the lung tissue
    
    • inhalation
    • exhalation
  • also effects any structure passing through the space
    
    • vena cava
    • lower trachea
    • mainstem bronchi
    • vessels

Question 6

Characterize the Trachea and Bronchi

Answer 6

• Pseudostratified columnar ciliated epithelium (Mucociliary escalator)
• Goblet cells:
  
  • mucus
  • electrolytes-ELF
• Smooth Muscle, submucosal glands, cartilage

Question 7

Cartilage fxn:

Answer 7

Prevents teh airway from collapsing

Question 8

Characterize the bronchioles

Answer 8

• Simple cuboidal and ciliated epithelium
• Clara cells
  
  • secretory
  • can differentiate into ciliated cells
• smooth muscle

Question 9

characterize the respiratory bronchioles

Answer 9

• Simple cuboidal epithelium
• Clara cells
• Smooth Muscle

Question 10

Characterize the Alveolar Ducts

Answer 10

• Squamous epithelium
• Smooth Muscle

Question 11

Characterize the Alveoli

Answer 11

• Alveolar type I and II pneumocytes

Question 12

identify airway

Answer 12

Trachea

• cartilage forms tehh horseshoe
• muscle connects the ends of the horsehshoe

Question 13

How much type I pneumocyte is there?

Answer 13

• Thin, elongated
• large surface area:
  
  • cover 95% of alveolar surface
    
    • at birth: 2.8m
    • Adult: 85m (tennis court)
  • Alveolar number:
    
    • at birth: 24x10^6
    • Adult: 300x10^6
• Thin blood-gas barrier-0.3um
  
  • share basement membrane with capillary endothelium

Question 14

Diffusion of air is proportional to what?

Answer 14

• surface area
  
  • _​_inversely proportional to distance (thickness)

Question 15

What are alveolar macrophages?

Answer 15

• Phagocytose foreign material and dead cells
• Secrete cytokines and chemokines to attract inflammatory cells if need
  
  • inflammation is not ideal in the lungs

Question 16

What are fibroblasts?

Answer 16

• Produce collagen and other components of the extracellular matrix for support
• brown staining cells

Question 17

Lymphatic System

Answer 17

• drain interstial fluid to prevent pulmonary edema
• In the lungs, if the interstitium is full of fluid it spills into the alveoli and impairs gas exchange
• lungs can’t swell bc it is surrounded by the walls-fluid ends up filling the lungs and is gravity dependnt

Question 18

How are the lungs innervated?

Answer 18

• lungs and thorax are innervated by motor, sensory, and autonomic nerves
  
  • the diaphragm
    
    • phrenic nerve-breathing at rest
      
      • autonomous breathing
  • Muscles of chest wall and abdomen
    
    • segmental intercostal nerves=Auxillary muscles and conscious breathing
    • chest wall T2-T6
    • Abdomen T7-T12
  • Airway smooth muscle and glands
    
    • via ANS
      
      • parasympathetic=Vagus nerve
      • Sympathetic ganglia
• Feedback control to stretch or inhale an irritant

Question 19

Type I vs Type II Alveolar Pneumocytes

Answer 19

• Type I cells
  
  • thin, elongated
  • 95% of alveolar surface
  • gas exchange
• Type II Cells
  
  • cuboidal
  • 2% of alveolar surface
  • secretes surfactant
  • progenitor of type I cells

Question 20

Pores of Kohn

Answer 20

• Alveoli
• interalveolar connections
• holes in adjacent alveoli to allow even distribution of air

Question 21

Large conducting airway vs small conducting airway vs alveolus

Answer 21

• Large conducting airway
  
  • Trachea and Bronchi
    
    • pseudostratified ciliated columnar epithelium
    • Goblet cells
    • Smooth muscle, submucosal glands, cartilage
• Small Conducting airway
  
  • Bronchioles, Respiratory bronchioles
  • Simple cuboidal (ciliated) epithelium
  • Clara cells
  • Smooth muscle
• Alveolus
  
  • Alveolar ducts, Alveoli
    
    • Simple squamous epithelium
    • Smooth muscle