Anatomy & Physiology of the Respiratory System Flashcards
Thoracic vertebrae & Ribs
Except for ribs 1 and 10-12, the head of each rib articulates with 2 vertebrae. The head of the rib attached inferiorly to the same numbered vertebrae and superiorly to one vertebrae higher.
The transverse process of the vertebrae attaches to the facet on the tubercle of the rib, forming the costotransverse joints.
Muscles of inspiration
Diaphragm, external intercostals, and parasternal internal intercostals
Accessory muscles of inspiration
Sternocleidomastoid, scalenes, pectoralis major (sternal portion), petoralis minor, and serratus anterior.
Muscles of exhalation
During quiet breathing, exhalation results from passive recoil of the lungs and ribcage.
During forceful breathing, the rectus abdominis, external and internal oblique, and transverse abdominis depress the lower ribs and the abdominal contents, pushing up the diaphragm and assisting with active exhalation.
Upper respiratory tract
Nasal cavity, pharynx (nasopharynx, oropharynx, laryngopharynx), and laryxn.
Humidifies, cools or warms inspired air and filters foreign matter before it reaches alveoli.
Lower respiratory tract
Extends from the larynx to the alveoli.
The trachea extends from the larynx (base of neck) to the carina (level of 4th thoracic vertebrae and sternal angle). Divides into the R and L main bronchi at carina.
Lung lobes
R lung has 3 lobes: upper, middle, and lower.
L lung has 2 lobes: upper and lower. Lingula analogous to R middle lobe.
Right Lung Bronchopulmonary Segments
R lung has 10 segments.
R main bronchus gives rise to the superior, middle, and inferior lobar bronchi.
R superior lobar bronchi divides into apical, anterior, and posterior segmental bronchi.
R middle lobar bronchi divides into medial and lateral segmental bronchi.
R inferior lobar bronchi divides into superior, medial basal, anterior basal, lateral basal, and posterior basal segmental bronchi.
Left Lung Bronchopulmonary Segments
L lung has 8 segments.
L main bronchus divides into the superior and inferior lobar bronchi.
L superior lobar bronchus divides into a superior and inferior (lingular) division.
-The superior division divides into the anterior segmental bronchus and the apicoposterior segmental bronchus.
-The inferior division divides into the superior and inferior segmental bronchus.
L inferior lobar bronchus divides into the superior, lateral basal, posterior basal, and anteromedial basal segmental bronchi.
Plaeurae
Visceral pleura covers the surface of the lungs.
Parietal pleura covers the inner surface of the chest wall, ribs, vertebrae, and mediastinum.
The two pleura are usually in contact with each other, separated only by serous fluid.
Pneumothorax - air in the pleural space
Hemothorax - blood in pleural space
Also pus or increased amount of serous fluid can compress the lung and cause respiratory distress.
Lung innervation
Anterior and posterior pulmonary plexuses.
Innervated by both sympathetic and parasympathetic nerves containing both efferent and afferent fibers.
Postganglionic sympathetic fibers innervate the smooth muscles of the bronchi and pulmonary blood vessels.
Parasympathetic innervation of these structures is via the vagus nerve.
Control of breathing
Breathing is controlled by the central respiratory center in the brainstem and peripheral chemo- and mechano-
receptors in the lungs, airways, chest wall, and blood vessels. Using feedback from receptors, the respiratory center can stimulate motor neurons that innervate respiratory muscles for voluntary control of breathing.
Central chemoreceptors
In medulla
Respond to increase in partial pressures of CO2 and hydrogen ion by increasing ventilation
Peripheral chemoreceptors
In carotid body
Respond to increase in partial pressures of CO2 and hydrogen ion and hypoxemia by increasing ventilation
Mechanoreceptors
Inhibit muscle activity when the force of contraction reaches potentially injurious levels
