Lecture 1.1: Anatomy of the Respiratory System Flashcards
What are the 2 parts of the Respiratory System?
Upper and Lower
What makes up the Upper Respiratory Tract? (4)
- Nasal cavity
- Paranasal sinuses
- Pharynx
- Larynx above vocal cords
What makes up the Lower Respiratory Tract? (4)
- Larynx below the vocal cords
- Trachea
- Bronchi
- Bronchioles
What anatomical structures do the lungs contain? (4)
- Respiratory Bronchioles - Transitional
- Alveolar Ducts
- Alveolar Sacs Respiratory
- Alveoli
How do the Ribs 1-7 articulate with the sternum anteriorly?
• Ribs 1 - 7 connected to sternum via costal cartilages
How do the Ribs 8-10 articulate with the sternum anteriorly?
• Ribs 8 - 10 connected to the costal cartilage above
How do the Ribs 11-12 articulate with the sternum anteriorly?
• Ribs 11 & 12 end free in the abdominal muscles (`floating ribs’)
What are the Typical Ribs?
• Ribs 3-9
• Head: 2 articular facets
• Neck
• Tubercle: 1 articular facet for articulation with transverse process of the
corresponding thoracic vertebra
• Shaft: costal groove under lower border which protects the intercostal vessels
& nerve
Structure of 1st Rib (Atypical)
- Forms upper border of superior thoracic aperture
- Short and thick
- Single articular facet for the costovertebral joint
- Flattened from top to bottom
- Grooves for: subclavian artery, subclavian vein, lowest trunk of brachial plexus
Where do Rib Fractures usually occur? Why?
- Usually Middle Ribs
* Crush Injuries/Direct Trauma
Complications of Rib Fractures?
- Soft tissue injury from broken fragments
* Risk of damage to lungs, spleen or diaphragm
When is the affected area in a rib fracture not under control of the thoracic muscles?
• If 2+ fractures occur in 2+ adjacent ribs
What is Flail Chest?
Defined as two or more contiguous rib fractures with two or more breaks per rib
What Intercostal Muscles are used in Inspiration?
• External Intercostal Muscles
What Intercostal Muscles are used in Expiration?
- Internal Intercostal
* Innermost Intercostal
Diaphragm Structure and Position?
- Double-domed musculotendinous sheet
* Inferior aspect of the rib cage
Functions of the Diaphragm
• Separates thoracic cavity from abdominal cavity
• Contraction and Relaxation alters volume of thoracic cavity and lungs
• Primary muscle of inspiration and expiration (70% chest expansion in quiet
respiration)
What does the Diaphragm attach to?
- Anteriorly to xiphoid process and costal margin
- Laterally to ribs 11 and 12
- Posteriorly to lumbar vertebrae
What are the 3 Openings in the Diaphragm?
- Vena Caval Hiatus (Foramen Venae Cavae)
- Oesophageal Hiatus (Hiatus Oesophagus)
- Aortic Hiatus (Hiatus Aorticus)
Caval Aperture/Hiatus
- Level: T8
- Central area of the central tendon
- Inferior vena cava
- Branches of right phrenic nerve
Oesophageal Aperture/Hiatus
- Level: T10
- Formed by fibres of the right crus, around oesophagus, to left of the midline
- Oesophagus
- Right and left vagus nerves (Gastric nerves)
- Oesophageal branches of Left Gastric vessels
- Lymphatics
Aortic Aperture/Hiatus
- Level: T12
- Between the right and the left crura, bounded by the median arcuate ligament
- Aorta
- Thoracic duct
- Azygous and Hemiazygous vein
What Nerves supply the Diaphragm?
- Right and left Phrenic Nerve
- Cervical plexus
- C3, C4, C5 (these keep the diaphragm alive!)
Why is Diaphragmatic pain often felt at the Shoulder Tip?
- Shoulder and diaphragm share common nerve supply - C3, C4
- Phrenic nerve
- Supraclavicular nerves
What is the Blood Supply of the Diaphragm?
- Primary: Inferior phrenic arteries (branch directly from the abdominal aorta)
- Others: Superior phrenic, Pericardiacophrenic, Musculophrenic arteries
What is a Diaphragmatic Hernia?
What is a Diaphragmatic Hernia? Compilcations?
- A birth defect where there is a hole in the diaphragm
* Abdominal organs move further up in body i.e. small intestine next to lungs
What are the 4 (Main) Body Cavities?
Cranial
Vertebral
Thoracic Cavity (Pleural Cavity, Mediastinum)
Abdomino-Pelvic Cavity
Where is the Mediastinum located?
Region between the lungs, extending from the sternum to the bodies of the vertebrae & from the superior thoracic aperture to the diaphragm
What is the Visceral Layer of the Pleural Cavity?
• Against the organs within the cavity
What is the Parietal Layer of the Pleural Cavity?
- Against the wall of the cavity
* Thin layer of pleural fluid between
What is the Function of the Pleural Cavity?
- Allows parietal and visceral parts to slide on one another
- Allows movement of the lung against chest wall
- Surface tension of pleural fluid keeps lung surface in contact with thoracic wall
- When thorax expands, the lung expands with it and fills with air
What is the Structure of the Lungs?
- Apex (above the level of 1st rib and into the root of neck)
- Base (inferior surface of the lung, on diaphragm)
- 2-3 Lobes (separated by fissures within the lung)
- Surfaces (costal, mediastinal, diaphragmatic)
- Lung Root (structures that suspend the lung from the mediastinum)
- Borders/Edges of the Lungs (anterior, inferior, posterior)
What is the Hilum in the Lungs?
The hilum is the point of entry on each lung for the bronchus, blood vessels, and nerves
Right Lung: Lobes and Fissures
- 3 Lobes (superior, middle, inferior)
* 2 Fissures (oblique and horizontal)
Left Lung: Lobes and Fissures
- 2 Lobes (superior and inferior)
* 1 Fissure (oblique)
Surface Markings of Lobes & Fissures: Oblique Fissure
- Between upper and lower lobes
* From spinous process of T4 posteriorly to the 6th costal cartilage anteriorly
Structure and Position of the Trachea
- Inner diameter of 1.5 to 2 centimetres (wider in males than females)
- 10 to 11 centimetres long
- Begins at the lower edge of the cricoid cartilage of the larynx (C6)
- Divides at the carina into left and right main bronchi (T4)
- 16–20 rings hyaline cartilage (incomplete and C-shaped)
