Thorax, Lungs & Pleura Flashcards
Describe the thorax
Area of body between neck and abdomen
Framework of the walls is thoracic cage
Flattened in front and behind, rounder at the sides
Has a narrow superior aperture and a larger inferior aperture
Give detail on superior thoracic aperture
Communication with the root of the neck
Bounded by:
Body of T1
Medial margin of 1st rib
Superior border of manubrium
Is an opening to allow structures to pass into the neck and upper limb
Compression causes thoracic outlet syndrome
Give detail on inferior thoracic aperture.
Communication with the abdomen
Closed by the respiratory diaphragm
Bounded by:
Body of T12
Inferior margins of 11th and 12th ribs
Costal margin
Xiphoid process
Allows passage of oesophagus, aorta, inferior vena cava, other nerves and vessels
What is the sternal angle?
The angle formed between the join of the manubrium and body of sternum.
Explain key features of the upper respiratory tract, beginning with air movement into the body.
External nose = location of nostrils
Nasal cavity = designed to condition the air, making it warm and moist, also removes any dirt.
Paranasal sinuses = add resonance to your voice, lighten the skull, and are also a home for respiratory epithelium and also produce mucus. These become inflamed during sinusitis.
Then air passes to pharynx and larynx.
Trachea continues from bottom of larynx and is covered in c-shaped cartilaginous rings.
Give details of key features of the pharynx.
Nasal choanae = communication between the nasal cavity and the nasopharynx
Soft palate = moves as you speak and swallow.
Uvula = attached to back of the soft palate. When you swallow the uvula sticks up over the nasopharynx so you don’t get fluid escaping into the nasal cavity.
Oropharynx = found at back of oral cavity
Tongue = powerful muscle formed floor
Laryngopharynx = descends from the oropharynx. Laryngopharynx continues as two structures either oesophagus or larynx.
Give detail on larynx
Musculoligamentous structure with a cartilaginous framework that caps the lower respiratory tract
Continuous below with trachea
Opens into the pharynx posterior and inferior to the tongue
Functions as a valve to close the lower respiratory tract and an instrument to produce sound
Give detail on trachea
Mobile and cartilaginous tube
Begins at the neck as a continuation of the larynx
Kept open by the presence of C-shaped rings of hyaline cartilage embedded in its wall
Trachea ends by dividing into right and left principal bronchi in the thorax
Bronchi divide dichotomously, giving rise to several million terminal bronchioles that terminate in one or more respiratory bronchioles in the lungs.
Right bronchus is shorter, wider and more vertically aligned so more likely to receive inhaled foreign bodies.
(left bronchus has to go behind the heart so its longer, narrower and more horizontal.)
Describe similarities and differences between right and left lungs
Each is suspended free in its plural cavity
Attached to the mediastinum by its root, where the main blood vessels and bronchi enter the lung.
Right lung slightly larger than left
Right has 3 lobes, left has 2
Both due to space taken on the left hand side of the thoracic cavity by the heart
Give detail on lung blood supply
The bronchi and connective tissue of the lung supplied by bronchial arteries, which are branches of the descending aorta
Alveoli receive deoxygenated blood from the terminal branches of the pulmonary arteries
Oxygenated blood leaving alveolar capillaries drains into the tributaries of the pulmonary veins.
Give detail on the 3 types of intercostals
External:
Fibres directed downward and forward from the inferior border of the rib above to the superior border of the rib below
Internal:
Fibres directed downward and backward
Innermost:
Deepest layer
Incomplete muscle layer that crosses more than one intercostal space
What is the role of accessory muscles?
Recruited during times of increased metabolic need
Also during dysfunction in the respiratory system
What are the 2 pleural membrane components?
Visceral & parietal
What is the visceral pleura?
Completely covers the outer surfaces of the lungs and extends into the depths of the interlobar fissure.
Not sensitive to pain, temperature or touch
Sensory fibres only detect stretch
Receives autonomic innervation from the pulmonary plexus
Network of nerves derived from the sympathetic trunk and vagus nerve
Arterial supply is via the bronchial arteries (branches of the descending aorta)
What is the parietal pleura?
Lines thoracic wall, thoracic surface of the diaphragm, lateral aspect of the mediastinum.
Sensitive to pressure, pain and temperature
Localised pain
Innervated by the phrenic and intercostal nerves
Blood supply from the intercostal arteries
