Respiratory system 2 Flashcards
What makes up the Lower Respiratory tract (LRT)
Larynx Trachea Bronchi Bronchioles Alveoli
What is the function of the LRT
Conducts air to/from site of gas exchange
Completes cleaning, warming and humidifying of air
Barrier between air and blood (large surface area for gas exchange)
Describe the larynx
Air passage
Cartilages protect and maintain open airways
Epiglottis closes over airway when swallowing
Where is the larynx located
Anterior to esophagus
From hyoid bone to trachea
What are the main bits of cartilage in the larynx
Epiglottis (just under tongue)
Thyroid cartilage (laryngeal prominence)
Cricoid cartilage
What is the glottis
Voice box
What are the two types of folds
Vocal folds
Vestibular folds
Where are the vocal folds
Attached to cartilages
Describe vocal folds
‘true’ vocal cords
Passing air causes vibrations (sounds waves)
Used for normal speech
What affects vocal folds
Testosterone - affects the cartilage and muscle - Longer, thicker folds. Deeper voice
Describe Vestibular folds
‘false’ vocal cords
Superior to vocal cords
Prevent foreign object entry to glottis
Produce deep sounds`
Where is the trachea located
Anterior to esophagus
Between larynx and primary bronchi
What are the functions of the trachea
Maintain patent airway - C-shaped cartilage rings
- Elastin fibres in lamina propria/submucosa
Clean, warm, humidify air
What connects the ends of C shaped cartilage rings
Trachealis - band of smooth muscle - contracts for coughing (as well as elastin fibres recoiling)
How are debris removed from the trachea
Mucociliary escalator - goblet cells and mucus glands coat surface and traps debris. Cilia move mucus up to pharynx to be swallowed and digested
How many lobes does each lung have
Right has 3
Left has 2
What is the hilum
Where bronchi and blood vessels enter
What is the costal surface of the lungs
Outer surface - against ribs
Describe 1 degree bronchi
Respiratory epithelium
Complete cartilage and smooth muscle rings
Describe 2 and 3 degree bronchi
Respiratory epithelium decease in height
Num. of goblet cells decrease
Cartilage plates (air P holds open)
Describe Bronchioles
Cuboidal epithelium
No cartilage
Thick smooth muscle for bronchoconstriction/dilation
No goblet cells
Describe Terminal Bronchioles
Each supplies a pulmonary lobule
Site of gas exchange
What is a pulmonary lobule
Made up of many alveoli (air sacks)
Most of lunch volume - enormous surface area
(150 million alveoli per lung)
Describe alveoli
Very thin - simple squamous epithelium on thin basement membrane
Covered in fine network of pulmonary capillaries
Open at one end
What are the two types of pneumocytes
(lung epithelial cells)
Type 1 squamous
Type 2 cuboidal
Describe Type 1 squamous
Forms respiratory membrane (blood-air barrier) with capillary wall and shared basement membrane
Describe type 2 cuboidal
Scattered amongst type 1
secrete surfactant - complex lipoprotein (phospholipid) - reduces surface tension of alveolar fluid.
Describe structure of alveolus
Roaming macrophage - removes debris
Capillary (oxygenated blood)
Connections to neighbouring alveoli
What are the layers of the respiratory membrane (From air to blood)
Alveolar cell layer (type 1 epithelial cell)
Fused basement membrane
Capillary endothelium
