M9S3 Respiratory Portion

Question 1

Respiratory portion

Answer 1

-lead to by the conducting portion
-serves to allow gas exchange between air and blood (important as cells need to absorb oxygen and expel carbon dioxide to survive)
-at this part of bronchial tree the walls of remaining structures only one cell layer thick and gases able to cross membrane easily

Question 2

The lungs

Answer 2

-respiratory portion makes up majority of the lung tissues within both lungs
-lungs located on either side of heart with thoracic cavity
-right lung slightly large than left due to heart positioning

Right lung:
-3 lobes: superior, middle, inferior
- 2 fissures that separate the lobes: horizontal and oblique fissures

Left lung:
-two lobes: superior and inferior
-superior lobe -> contains cardiac notch (a depression on anterior boarder of left lung that accommodates the space taken up by apex of heart)
-superior lobe -> small outfacing process on it called lingula that covers heart
One fissure that separate lobes: oblique fissure

*when spread out lungs have surface area of tennis court

Question 3

Surfaces of the lungs

Answer 3

-lungs close contact with surrounding structures so creates surfaces of lungs that named by structure in contact with

Apex
-most superior point
-sits just above first rib

Diaphragmatic
-sits superiorly to diaphragm (a dome-shaped skeletal muscle)
-base of lung known as diaphragmatic surface as rests on diaphragm

Costal
-named after adjacent ribs
-surface curves around lateral aspect of lung

Mediastinal
-medial surface
-contains entry and exit points for all vessels and airways at a structure known as hilus

Question 4

Pleural membranes

Answer 4

-lungs important organs for gas exchange so need to be protected
-pleural consists of 2 continuous membranes that form a sac around each lung
-secretes pleural fluid to fill pleural space between 2 membranes
-fluid act as lubricant, allowing visceral pleura of lung to slide freely on parietal pleura of thoracic wall during inflation and deflation

Parietal pleura
-an outer membrane attached to wall and floor of thoracic cavity around lungs
-continuous with visceral pleura at hilus of lungs where reflected inwards

Visceral pleura
-serous membrane attached to surface of lung that continuous with parietal pleura at hilus

Question 5

Structures of respiratory portion

Answer 5

1. Respiratory bronchioles
   -branch from terminal bronchioles (last structure in conducting portion)
   -first structure to contribute to gas exchange in lungs
   -thin walled ducts with simple ciliated cuboidal epithelium
   -continue to branch, ending with alveoli
2. Alveoli
   -alveolus is functional unit in lung where gas exchange takes place
   -each alveolus surrounded by capillaries in order to maximize amount of oxygen going into body and carbon dioxide leaving body

Question 6

Chronic obstructive pulmonary disease (COPD)

Answer 6

-lung disease make it hard to breath (inflammation and limitation of air flow in and out of lungs)
-describe breathing conditions like chronic bronchitis, asthma, emphysema
Causes: smoking, second hand smoke, dust, workplace fumes, biomass exposure, genetic disorders
-respiratory infections can make these people really sick
Normal lungs:
Air goes to bronchial and branch into bronchiole into alveoli (normally walls flexible so each air sac fill/deflate)
In COPD: bronchiole airway inflamed and full of mucous making it hard to breath (walls air sac damaged, not elasticy, floppy and air sacs trapped so fewer to supply oxygen to blood so lungs don’t deflate like normal