Anatomy of Respiration Flashcards
How does the sternum move?
Anterosuperiorly
Like a pump handle
How do the lateral shafts of the ribs move?
Elevate
Like bucket handles
What do the costotransverse joints unite?
Posterior rib with transverse process
What allows the middle ribs to rotate?
Costotransverse joints have concave transverse processes
What allows the lower ribs to slide?
Costotransverse joints have planar transverse processes
What muscles does normal breathing use?
Diaphragm
External intercostals
How does the diaphragm move during contraction?
Flattens and lowers
What does the diaphragm separate?
Thorax and abdomen
What does the diaphragm span?
Inferior thoracic aperture
Where are the attachments of the diaphragm? (5)
Costal margin
Scalloped attachments between floating ribs and transverse processes
Lumbar attachments/left and right crus
Central tendon with pericardium
Posterior of xiphoid process
What passes through the diaphragm?
Descending aorta
Oesophagus
Phrenic and vagus nerves
Inferior vena cava
What part of the diaphragm does the inferior vena cava pass through?
Central tendon
What innervates the diaphragm?
Phrenic nerve (mixed somatic)
On which side is the dome of the diaphragm higher? Why?
Right - liver
Where does the phrenic nerve originate?
C3, 4, 5
Describe the path of the phrenic nerve as it descends through the thorax
Outside pericardium
In front of root of lung
More lateral than vagus
How many layers of intercostal muscles are there?
3
What are the different intercostal muscles?
External
Internal
Innermost
What is the effect of the external intercostal muscles contracting?
Raise thoracic cage
What are the accessory/secondary muscles of respiration? (6)
Pectoralis major
Pectoralis minor
Sternocleidomastoid
Scalenes
Serratus anterior
Subcostal muscles and transversus thoracis
Where does pectoralis major attach?
Along length of clavicle and sternum
Where does pectoralis minor attach?
3, 4, 5 ribs
Where does the sternocleidomastoid attach?
Mastoid process to where the sternum meets the clavicle
Where do the scalenes attach?
Transverse processes of cervical vertebrae to first and second ribs
Which accessory muscles pull on the upper ribs?
Sternocleidomastoid
Scalenes
What are the subcostal muscles and transversus thoracis extensions of?
Innermost intercostal muscles
What happens during quiet inspiration?
Diaphragm descends 1cm
External intercostals contract
500ml air inhaled
What is the typical value of tidal volume?
500ml
What happens during deep inspiration?
Diaphragm descends 10cm
External intercostals contract
2-3L inhaled
What happens during deepest inspiration?
Diaphragm, external intercostals, scalene, SCM, pectoralis, serratus anterior used
~5L inhaled
What happens during quiet expiration?
PASSIVE
Elastic recoil of lungs
Diaphragm and external intercostals relax
What muscles are involved in forced expiration?
Anterior abdominal wall muscles and internal intercostals
What does the upper respiratory tract comprise of?
Nasal cavity
Oral cavity
Pharynx
Larynx
What is the pharynx subdivided into?
Nasopharynx
Oropharynx
Laryngopharynx/hypopharynx
What is a function of the larynx other than voice?
Act as a lid to increase thoracic and abdominal pressure in:
Coughing, sneezing, vomiting, defecating
What does the lower respiratory tract comprise of?
Trachea
Bronchi
Lungs
Describe the structure of the trachea
Single tube
Anterior C-shaped rings of hyaline cartilage
Posterior smooth muscle (trachealis muscle)
What is the carina?
Sensitive ridge before bronchi
Triggers cough reflex
What is the difference between the left and the right bronchi?
Left bends at a sharper angle due to heart
*Which division of bronchi has the least amount of cartilage?
Tertiary
What occurs at the alveoli?
Gas exchange
What are bronchopulmonary segments?
Well-defined regions of the lungs
Supplied by specific segmental bronchi and bronchial arteries
Encased in its own connective tissue
How many lobes do each of the lungs have?
Right = 3
Left = 2
What are the three main surfaces of the lung?
Costal
Diaphragmatic
Mediastinal
What is the lung root/hilum?
Site of entry/exit of airways, blood vessels and lymphatic vessels
Which lung has a horizontal fissure?
Right lung
Which lung has a cardiac notch and lingula?
Left lung
What is it called when the lung has collapsed?
Pneumothorax
What are the pleura?
Serous membranes that line the lungs and the thoracic cavity
What is the space between the two pleural membranes?
Pleural cavity
Which pleura lines the lung?
Visceral
Which pleura lines the thoracic cage?
Parietal
What is the pulmonary ligament?
Extra membrane at the root of the lung due to imperfect continuous pleura
What is the layer of tissue between the parietal pleura and the thoracic wall?
Endothoracic fascia
What is the function of the pleura?
Smooth movement of lungs
Negative pressure keeps lungs inflated
What is the value of intrapleural pressure?
(-)4mmHg
What is the potential pleural space?
Area in thoracic cage that is available to be filled by lungs
Where is the anterior-inferior limit of the lung?
6th rib
Where is the lateral-inferior limit of the lung?
8th rib
Where is the posterior-inferior limit of the lung?
10th rib
Where is the apex/superior limit of the lung?
Above 1st rib
What innervates the pleura?
Intercostal nerves
Phrenic nerves (diaphragmatic)
What is the difference between the pulmonary and bronchial blood supply?
Pulmonary = blood to be oxygenated
Bronchial = nutritive function (oxygenated)
Which vessels do the lymphatic capillaries travel with in the lung?
Pulmonary arteries
Where does the right bronchial artery branch from?
Right third posterior intercostal artery
Where do the inferior and superior left bronchial arteries branch from?
Descending aorta
What nerves travel with the bronchial arteries?
Bronchomotor nerves
