Anatomy Of The Respiratory System Flashcards
Walls of the thoracic cavity
- anterior: sternum + costal cartilages
- lateral: ribs
- posterior: vertebral bodies
- inferior diaphragm
What are the two analogies of the movement of the chest wall during breathing?
- bucket handle movement
- pump handle movement
Explain the bucket handle movement of the chest wall
Ribs move out laterally to increase lung volume
Explain the pump handle movement
Sternum moves anteriorly + ribs swing up like pump handle to increase lung volume
What are the 3 types of intercostal muscles?
External
Internal
Innermost
What intercostal muscles are used in inspiration?
External intercostal muscle
What intercostal muscles are used in expiration (forced)?
Internal + innermost intercostal muscle
What levels do these structure pass through the diaphragm?
- vena cava
- oesophagus
- aortic hiatus
How can you remember this?
- vena cava: T8
- oesophagus: T10
- aortic hiatus: T12
Number of letters in each
Where should you insert a chest strain?
Why?
- Above the rib
- To avoid hitting the intercostal neurovascular bundles which lie beneath the ribs
Outline venous drainage of the intercostal muscles
Intercostal vein > azygous vein > superior vena cava
What nerve supplies the diaphragm ?
Phrenic nerve C3-5
‘C3,4,5 keeps the diaphragm alive’
Outline the lobes of the lungs
3 right
2 left
What do the oblique and horizontal fissure do?
Separate the lobes of the lungs
What is the area in between the lungs called?
Mediastinum
What spinal level splits the superior + inferior mediastinum?
C4-5
Describe the layout of the hilum of the lungs
- airways: posterior
- branches of pulmonary arteries: superior
- tributaries of pulmonary veins: inferior
What is the costodiaphragmatic recess?
The space where the lungs will expand in inspiration
Outline the blood supply to the lungs
- pulmonary arteries directly from the heart
- bronchial artery directly from the aorta
What blood supply helps the lungs during a pulmonary embolism when the pulmonary arteries are blocked?
Bronchial arteries
Development of the respiratory tract
Develops as a diverticulum from the pharynx
Role of the epiglottis
To ensure food and air enter oesophagus + trachea respectively
What epithelial cells line the airways?
Ciliated pseudostratified columnar
What makes up the lamina propria?
Basement membrane
Loose connective tissue
Describe the layers of the airway walls
Mucosa
- epithelium: ciliated pseudostratified columnar + goblet cells
- lamina propria: basement membrane + loose connective tissue
Submucosa
- smooth muscle
- connective tissue: contain the bronchial mutinous glands
Cartilage in bronchi
Layers of the mucosa in the airways
- epithelium: ciliated pseudostratified columnar + goblet cells
- lamina propria: basement membrane + loose connective tissue
Layers of the submucosa in the airways
Smooth muscle
Connective tissue (contains the bronchial mucinous glands)
What is also found in the walls of the bronchi but not the other airways?
Cartilage
What is the carina?
The cartilage situated at the point where the trachea divides into the left and right main bronchus
Function of type I pneumocytes
Squamous epithelial cells
Responsible for gas exchange in alveoli
Function of type II pneumocytes
Produce surfactant
Nerve root of the phrenic nerve
C3-5
‘C3,4,5 keeps the diaphragm alive
What makes up the neurovascular bundles below the ribs?
Intercostal vein
Intercostal artery
Intercostal nerve
Where does the trachea start and end?
- starts: lower border of the cricoid cartilage C6
- ends: at T6 as it divides into the main bronchi
Outline the attachment of the ribs
- 1-7 attach to sternum via costal cartilages
- 8-10 attach to costal cartilage of 7th rib
- 11-12 are floating ribs
TRUE RIB: 7 letters > 1-7 true ribs
FLASE RIB: 8 letters > 8-10 false ribs
FLOATING RIB: 11 letters > 11-12 floating ribs
Location of Clara cells
Terminal bronchioles
Function of Clara cells
Produce surfactant + mucous
Is air resistance in the bronchioles greater in expiration or inspiration?
expiration
.
- during inspiration the alveolar expand
- this increases radial traction on the bronchioles
- bronchiole diameter is bigger
.
- during expiration, radial traction is lower
- so bronchioles have a smaller diameter
- increases air resistance
What effect does an absence of surfactant have?
- higher surface tension of alevoli
- the pressure within the small alevoli is higher than large alevoli
- small alveoli collapse in large alevoli
- making fewer but larger air spaces
How does surfactant reduce surface tension?
- surfactant is amphipathic
- hydrophilic lie in the alveolar fluid
- hydrophobic ends project into the alveolar gas
- surfactant molecles are interspersed between water molecules
- bonds disrupted between molecules
- surface tension reduces
How much of the tidal volume reaches the alevoli?
2/3rds
Blood supply to the visceral pleura
Bronchial arteries
Blood supply to the parietal pleura
Intercostal arteries
What do the intercostal nerves innervate?
- Sensory: parietal pleura + kin overlying each intercostal space
- Motor: intercostal muscles
What does the oblique fissure separate?
- Right: middle and inferior lobes
- Left: upper and lower lobes
What does the horizontal fissure separate?
Right superior and middle lobes
