basic respiratory system

Question 1

why do we need a respiratory system

Answer 1

distance means we cant diffuse through our surface so it provides an interface between the environment and the tissues via blood

Question 2

2 main challenges to operate effectively

Answer 2

• surface must be thin and moist allowing gas to dissolve and diffuse
• a muscular pump is required to move air in and out of lungs via pressure gradients

Question 3

functions of the RS (4)

Answer 3

• gas exchange between enviro and blood
• control acidity of body (co2 levels and acid in body)
• filter inhaled air protecting body
• vocalisation (speech)

Question 4

basic structure of lungs
- how to describe them basically and what do they do when air enters and leaves
- how many lobes does each lung have
- what makes up the thoracic cavity

Answer 4

• They are large, spongy, and elastic “bags” that they fill up with air with every breath (expand and recoil allowing this).
• Each lung is divided into lobes. right lung three lobes, left lung has only two (smaller as room for lv of heart).
  Lung tissue fills entire thoracic cavity, except the mid-sternal line where the heart, major vessels, and the oesophagus are.

Question 5

the pleural sac
- what is it
- 2 functions

Answer 5

• a double-walled enclosure of the lungs filled with pleural fluid
• Reduces friction from movement on the surface of the lungs (allows lungs to move throughout life, healthily)
• Fixes lungs on thoracic wall without any physical attachments

Question 6

the bones and muscles that make up the thoracic cavity and their functions as a whole

Answer 6

• The bones (rib cage and spine) offer rigid protection to sensitive organs (heart and lungs).
• The muscles (diaphragm, intercostals (ext+int), abdominals) support the rib cage and create pump (pressure difference) that drives air flow.

Question 7

what makes up the upper respiratory tract

Answer 7

nostrils, nasal cavity, mouth, throat (pharynx) and voice box (larynx)

Question 8

nasal cavity in more detail
- what increase the surface area of the nasal cavity
- why does the surface of the nasal cavity have a very high blood supply
- what is the first line of defence at the vestibule (entrance)

Answer 8

• turbinates (or conchae) are bony dividers
• helps warm up and humidify the inspired air as it flows over it.
• Small hairs and mucus in the vestibule help trap inhaled particles so that they can be blown back out

Question 9

lower respiratory tract
- what makes it up
- 2 zones and their functions
- how many divisions are there from trachea to alveoli and what is end surface area

Answer 9

• trachea, bronchi, bronchioles, alveoli
• conductive zone/dead space (trachea and bronchial tree)- moves air in and out
• exchange zone (alveoli)- gas exchange
• 23 divisions, end surface area around 100m2

Question 10

surface of the airways
- different parts and what they all do

Answer 10

• Columnar epithelial cells (with cilia on top)
• Cilia- hair like cells. Have a stroke phase and relax phase (constantly moving mucus 1 way back away from lungs)
• Goblet cells- secrete mucus which traps inhaled particles
• Watery saline layer- allows cilia to move to push mucus towards pharynx

Question 11

3 functions of the airways

Answer 11

• Warming up of inspired air.
• Humidification of dry inspired air.
• Filtration of inhaled foreign materials.

Question 12

alveoli
- what are the 2 types of cells that separate air in alveoli to blood in capillaries
- 2 reasons why the barrier is optimal for gas exchange

Answer 12

• capillary endothelial cells and a single layer of alveolar epithelial cells.
• very thin, huge SA

Question 13

3 main types of cells in alveoli

Answer 13

Type 1- for gas exchange
Type2- releases surfactant which creates alveolar stability preventing collapse, allowing gas to diffuse across
Alveolar macrophages- ingest foreign material that made it to lungs