09 - Respiratory Anatomy

Question 1

Functions of the respiratory system

Answer 1

perform gas exchange
regulate blood pH
provide for olfaction
provide for phonation (sound)

Question 2

Structures of the respiratory system

Answer 2

upper and lower airways
lungs and pleura
thoracic cage
muscles of respiration

Question 3

Describe the upper airway
And the route of airflow

Answer 3

structures above the larynx (vocal cords)

Route of airflow
1. external nares (lined with nose hairs)
2. nose
3. nasal cavity (nasal conchae)
- increase SA for rapid warming and humidification of air and traps air
4. pharynx (3 zones)
- nasopharanyx
- oral pharanyx (also for food)
- laryngeal pharanyx (also for food)
5. larynx

Question 4

What lines the nasal cavity

Answer 4

respiratory epithelium (cilia and goblet cells; a mucous membrane) and a smaller olfactory epithelium

Question 5

What lines the oral cavity

Answer 5

pseudostratified cilliarly epithelium

Question 6

Describe the purpose of the epiglottis

Answer 6

cartilaginous structure

covered by mucus membrane

stem attached to thyroid cartilage
leaf is free to move

protects the trachea from food stuff (aspiration) during deglutition (swallowing)

also aids in explosive maneuvers
- coughing/sneezing
- micturition
- defacation
- labour and delivery
structural support

Question 7

What are the structures of the lower airways

Answer 7

below the larynx
- trachea
- bronchi
- alveoli
- lungs

Question 8

Describe the trachea

Answer 8

~12cm long, ~3m diameter
C-shaped cartilage maintain patency
tracheal smooth muscle (posteriorly)

bifurcates (divides) into primary bronchi

lined by ciliated pseudostratified columnar epithelium –> forms a mucociliary apparatus

carina = internal ridge at bronchial junction (associated with cough reflex)

Question 9

What are the four layers of walls of the trachea

Answer 9

1) epithelium
2) submucosa
3) hyaline cartilage
4) adventitia

Question 10

Describe the bronchi and bronchioles

Answer 10

1. primary (main) bronchi enter the hilum of the lungs to direct air to the right and left lung
   - supported by rings of cartilage
   - right primary (main) bronchus –> short, wide, vertical
   - left primary (main) bronchus –> long, less vertical
2. secondary (lobar) bronchi dirext air to each lobe of the lung (3 right, 2 left)
   - supported by plates of cartilage

lined by ciliated pseudostratified epithelium

Question 11

Describe the lungs and lobes

Answer 11

lobes separated by fissures visible on the surface of the lungs
- right: superior, middle, inferior lobes
- left: superior and inferior lobes

lungs surrounded by pleural cavities that are lined by a serous membrane
- parietal pleura
- visceral pleura

Question 12

Describe the tertiary (segmental) bronchi

Answer 12

direct air into discrete bronchopulmonary segments within the lobes of the lungs
- right = 10 segments
- left = ~8 segments

anatomically and functionally independent –> contain many small segments called lobules

forms a bronchial tree with extensive branching

at the ends, plates of cartilage get replaced by elastic fibres and smooth muscle

Question 13

What does a terminal bronchiole mark

Answer 13

the beginning of a lung lobule (where gas exchange occurs)

Question 14

Describe the lung lobules (acinus)

Answer 14

each lobule wrapped in elastic tissue and contains
- branch of a terminal bronchiole
- arteriole
- venule
- lymphatic vessel

terminal bronchioles –> respiratory bronchioles –> alveolar ducts –> alveolar sacs –> alveolus

Question 15

What are the types of alveolar cells

Answer 15

Type 1: line the alveolar wall (pneumocyte)
- primary site of gas exchange

Type 2: secrete alveolar fluid and a substance called surfactant (reduces the surface tension of alveolar fluid to make it easier to breathe)
- elastic fibers also help to keep the alveoli open

Alveolar macrophages: provide immune surveillance

Question 16

What makes up the gas exchange membrane

Answer 16

type 1 pneumocyte
basement membrane
pulmonary capilary endothelial cell

Question 17

What are the two circulations of the lung

Answer 17

conducting regions of the lungs (trachea to terminal bronchiole) is supplied by the bronchial circulation
- receives oxygenated blood from the systemic circuit

respiratory regions of the lung (terminal bronchiole to alveolus)
- receives deoxygenated blood from the pulmonary circuit

Question 18

Describe the thoracic cage

Answer 18

consists of 12 pairs of ribs and associated costal cartilage
- ribs articulate with 12 thoracic vertebrae

7 pairs of true ribs –> touches sternum
5 pairs of false ribs –> don’t touch sternum (free floating)

contains sternum (manubrium, body, xiphoid process)

Question 19

Describe the features of the thoracic vertebrae and associated ribs

Answer 19

ribs possess facets for articulation with the vertebrae (synovial joint)

pedicle
lamina
body

head
rubercle
costal angle –> weakest part of the rib
costal groove –> houses an intercostal VAN) intercostal vein, artery and nerve)

Question 20

What does the phrenic nerve innervate

Answer 20

skeletal muscle in the diaphragm

Question 21

Describe the diaphragm

Answer 21

attaches to the inferior aspects of the rib cage and acts upon a central tendon

seperates the pleural cavity from the peritoneal cavity

many structures must pass through the diaphragm (one caval opening and two hiatuses)