CBT1 Anatomy of respiratory and cardiovascular systems Flashcards
What is the main job of the respiratory system?
Most efficient delivery of air into the lungs
What is the main job of the cardiovascular system?
most efficient delivery of oxygen and all the other blood-borne molecules (proteins, lipids, carbohydrates) to the tissues
Name the layers of the chest wall and lungs from superficial to deep
Skeletal muscle - affixed Skeleton - affixed Parietal pleura - separated by pleural fluid Visceral pleura - affixed Lung
What are the two parts of the lung organ?
The lung tissue and the chest wall
Describe the structure of the chest wall?
rigid support structure comprising mostly the ribcage, sternum and intercostal muscles. It naturally recoils outward.
Describe the structure of the lungs
soft tissue structures, very elastic, and naturally recoil inward. They provide a large surface area for gas exchange.
What are the two layers of connective tissue in between the lungs and chest wall?
- (visceral and parietal) pleura
- pleura fluid (lubricating fluid)
What is the pleura membrane attached to the lungs called?
visceral pleura
Where is the parietal pleura attached?
Inner surface of chest wall
What do the pleura act as?
The lung-chest interface and are integral to normal chest function
What volume of pleural fluid is there in between the pleura?
A few millilitres
What should the interpleural cavity pressure always be in healthy individuals?
negative (-5 cmH20)
atmospheric pressure = 0 cmH20
SA of lungs is roughly equal to?
Tennis court, much of this SA is in the alveolar region
How many litres of air do we inhale on average per day?
12,000 litres
What does patent refer to?
open airways
How are the cartilaginous airways held open?
- C-shape cartilage strips
- The open side of the dorsal strip is the dorsal side
Where is the open side of the cartilaginous airway most important and why?
Trachea, where the open side accommodate the oesophagus, and does not impede swallowing
Describe how the tensile strength of the cartilaginous airways is formed
The C-rings are slightly offset with each other (not stacked) thereby increasing airway wall support properties
How do the bronchioles remain open?
Not by cartilage but by surfactant to reduce surface tension and limit airway collapse
What are acini?
Discrete anatomical alveolar regions
What does bifurcate mean?
Branching off into two new branches called dichotomous branching
What do the two main bronchi split into?
four smaller extrapulmonary bronvhi
As the number of airways progressively increases, what happens to their diameter and length? and the cross-sectional area?
proportionally decreases
cross-sectional area increases markedly
In chronic obstructive pulmonary disease and other respiratory diseases which increase difficulty breathing, what is the diameter of the bronchioles?
<2mm
Describe the relationship between resistance to airflow and airway generation
There is an initial relatively small increase in resistance in the first few airway generations. But then resistance falls markedly, with virtually no resistance in the respiratory zone
How many different cell types are found in the airway? why would this change?
22
acute or chronic disease status
Describe the structures of the airway wall superficial to deep
Submucosa:
Cartilage
smooth muscle (tracheal/bronchial)
(submucosa gland found within smooth muscle)
(blood vessels found within smooth muscles too)
Mucosa:
Goblet and ciliated cells beside each other
mucus
airway
Describe how the airways are cleared of inhaled particles
Mucus on the epithelia surface traps inhaled particles. beating cilia moves the mucus. This process is called mucociliary clearance
What is the alveolar region also known as?
lung parenchyma
Within the alveolar region, what has close interactions?
type 1 alveolar cell
capillary endothelial cell
erythrocyte
fibroblasts
What do type 2 alveolar cells do?
They have a variety of functions
Replicate to replace type 1 cells
Secrete surfactant and antiproteases
Contribute to xenobiotic metabolism
What do macrophages in alveolus do? How many normally in healthy individuals?
2-3/alvelolus
ingest inhaled particles and microbes
What do fibroblasts do to aid the alveoli?
produce extracellular matrix that helps to hold the alveolar unit structures together