Overview of the Respiratory System and Anatomy Flashcards
Regions of Parietal Pleura
Costal Pleura
- adjacent to ribs
Diaphragmatic Pleura
- adjacent to diaphragm
Mediastinal Pleura
- adjacent to pericardial sac
Bronchial Tree
Superior/Larger
- trachea
- primary bronchi to right or left lung
- secondary bronchi to each lobe of lung (2 on left, 3 on right)
- tertiary bronchi to each bronchopulmonary segment
- smaller bronchi
- bronchioles
- alveoli
Inferior/More Specific
Recesses of Pleural Sacs
- Pleural sacs extend beyond borders of lungs.
- Parietal pleura reflects back on itself.
- Spaces created are usually very small.
- Larger during expiration
- Fluid from infection or bleeding can collect here
- not normally a space but can be a space in cases of infection
- clinically important
neutral blood pH
7.4 is the neutral blood pH
Surface Anatomy of Lungs
Functions of Respiratory System
- Provides oxygen
- Eliminates carbon dioxide
- Regulates the blood’s hydrogen ion concentration (pH) in coordination with the kidneys
- Forms of speech sounds (phonation)
- Immune functions (defense against microbes/dust in air)
- Influences arterial concentrations of chemical messengers by removing some from pulmonary capillary blood and producing and adding others to this blood
Diaphragm
Skeletal Muscle
Dome-shaped
Central tendon (middle of diaphragm)
Alveolar Cell Types
Type I pneumocytes (95%)
- Flat; make diffusion barrier with capillary endothelial cells
Type II pneumocytes (5%)
- Produce surfactant
Macrophages (‘dust cells’)
- Phagocytes; move freely through alveoli
Bronchopulmonary Segments
- Anatomically and functionally independent units.
- Pyramidal in shape: apex toward hilus; base toward pleural surface
- Supplied by one tertiary (segmental) bronchus and one segmental branch of pulmonary artery.
- Pulmonary veins travel between segments; drain adjacent segments.
- Each bronchopulmonary segment can be removed without affecting the rest of the lung
*need to know all of these segments!
Vocal Ligaments
- Elastic tissue
- Underlie vocal folds, bilaterally
- Run between each arytenoid cartilage and the internal surface of thyroid cartilage
Right Lung v. Left Lung At Hilus
“RALS”
Right Lung Pulmonary Artery = Anterior to Bronchus
Left Lung Pulmonary Artery = Superior to Bronchus
Things produced and added by lung cells
- bradykinin
- histamine
- serotonin
- heparin
- prostaglandins Ex and F2a
- endoperoxidases (prostaglandins G2 and H2)
Trachea
- Just inferior to larynx
- Branches at carina
- at T4/5 vertebral level
- (at sternal angle)
- superior to the heart
- at T4/5 vertebral level
- to form right and left primary (main) bronchi
Three Major Foramina of of Diaphragm
Vena Caval Foramen (T8):
- Inferior Vena Cava
- Right Phrenic N.
Esophageal Hiatus (T10):
- Esophagus
- R & L Vagal Trunks
Aortic Hiatus (T12):
- Aorta (aorta kind goes behind diaphragm; don’t want it to be affected by contraction of the muscles in the diaphragm)
- Thoracic Duct
Conducting Airways: Superior to Inferior
nasal cavity
pharynx
larynx (vocal folds)
trachea
Conducting Airways and Respiratory Airways responsible for:
Conducting Airways
- warm, moisten and filter incoming air
- deliver air to alveoli
Respiratory Airways
- gas exchange
Laryngeal Cartilages
9* Laryngeal Cartilages (*we only care about 5)
3 unpaired
- Epiglottis
- Elastic cartilage
- Covers opening of larynx
- Thyroid cartilage
- Hyaline cartilage
- Shield-shaped; doesn’t cover posterior larynx
- Cricoid cartilage
- Hyaline cartilage
- Only complete ring of cartilage in airway •
3 pairs* (*we only care about 1 pair)
- Arytenoid cartilages
- Hyaline cartilage
- Articulate with superior part of posterior cricoid cartilage • Very movable
- Attach to vocal ligaments
Diffusion Barrier (Air-Blood Barrier)
Pleural sacs
Parietal Pleura
- lines inside of thoracic cavity (rib cage).
Visceral Pleura
- lines surface of lungs.
two layers are continuous at the hilus of the lung
Lining of Respiratory System changes through conducting and respiratory passageways
Epithelium and underlying structures change composition through conducting and respiratory passageways.
- height of epithelium decreases; transitions from more columnar to more cuboidal
- goblet cells & glands decrease
- cartilage decreases
- relative amounts of smooth muscle & elastic fibers increase
Bronchi and Lobes of Lungs
Right lung = 3 lobes
Left Lung = 2 lobes
Primary (Main) Bronchi
- one to each lung
Secondary (Lobar) Bronchi
- one to each lobe
Tertiary (Segmental) Bronchi
- one to each bronchopulmonary segment
Things metabolized, modified, or cleared by lungs
prostaglandins E1, E2, and F2a; norepinephrine
Three Regions (Spaces) Within the Larynx
Vestibule
- opening of larynx to vestibular folds
Ventricle
- between the vestibular and vocal folds
Infraglottic Cavity
- vocal folds to trachea
Vocal Folds + Space Between = Glottis
Right vs. Left Main Bronchus
Right main bronchus: • straighter • shorter • wider
how do cilia work and role of smoking
- cilia face the lumen and beat upward; covered in water and mucous that can catch particulate matter to move it back up out of body
- Smoke can kill cilia; why smokers get hacking cough (trying to compensate for lack of cilia)
Hilus of Lung
- Only place where structures enter/ exit lungs
- Contains:
- Bronchi
- Blood vessels
- Pulmonary A/V
- Bronchial A/V
- Lymphatics
- Lymph Nodes
- Nerves
Larynx has 2 main functions:
- Maintain a patent airway (cartilage)
- Close off airway if needed (muscles)
- Swallowing
- Cough reflex
- (+Speech)
have to close the larynx off every time we swallow
histology of alveoli
Histology of the Trachea
- 16-20 C-shaped hyaline cartilages
- airway stays patent
- Smooth muscle on posterior side
- Allows esophagus to expand
- Lined with respiratory epithelium
why are lungs good place to add things to blood?
Has 5L of output each pump passing through it whereas systemic blood has 5L totally being shared across all body
Vagus Nerve (Cranial Nerve X)
- Originates from brainstem
- Travels through neck into thorax and abdomen
- Two branches of vagus nerve innervate the larynx (motor and sensory)
- Superior laryngeal nerves (in M&M)
- Recurrent laryngeal nerves
- Right: loops around subclavian artery
- Left: loops around aortic arch; loops around ligamentum arteriosum (?)
- Pathology in thorax can affect this nerve
Lobes and Fissures of the Lungs
Lung in Situ
- Surround the heart
- Apex of each lung is superior to first rib
- Bases rest on diaphragm
Respiratory Epithelium
- Lines most of the conducting parts of the respiratory system
- Pseudostratified columnar ciliated epithelium with goblet cells
- Lamina propria and submucosa contain numerous seromucous glands
Movement of Diaphragm
- Flattens with inspiration.
- Increases thoracic volume/decreases thoracic pressure.
- Moves 4-6 cm with each breath.
- Boundary between thorax and abdomen moves with each breath.
Airway Branching in the Human Lung
Cartilaginous rings help hold trachea and bronchi open
Alveoli - where gas exchange occurs
Alveolar sacs are like a cluster of grapes (with the grapes being alveoli)
Vocal Folds and Vestibular Folds
Vocal Folds (True Vocal Folds)
- Stratified squamous epithelium (to resist frictional forces)
- Overlie the vocal ligaments
- Changes in length, tension, proximity involved in sound production
- Can close off airway
- Tenser (or shorter) vocal fold = Faster Vibration, Higher Pitch
Vestibular Folds (False Vocal Folds)
- Respiratory epithelium
- Overlie vestibular ligaments
- Contain glands
- Not involved in sound production
Phrenic Nerve
- From cervical spinal nerves 3, 4, & 5
- Somatomotor
- Anterior to hilus of lung on each side
The Alveolar-Capillary Unit
- Alveoli = tiny, hollow sacs whose open ends are continuous with the lumens of airways
- Large surface area (480 million of them)
- Main site of gas exchange
- 280 billion pulmonary capillaries; 500-1,000 pulmonary capillaries per alveolus
- Total surface area between alveoli and pulmonary capillaries = 50-100m^2
- Space between alveoli and capillaries just a few microns (need to be thin for exchange)
Elastic Tissue in Alveolar Walls
long-term COPD patients can have large ribcages
Laryngeal Muslces
- Skeletal muscles
- Move the cartilages at joints
- Regulate airway
- Move vocal ligaments closer together/farther apart
- Change length & tension of vocal ligaments (speech)
- Contraction of all muscles together will close off airway (cough reflex)
Hilus anatomy: medial surface
Histology of Bronchial Tree (Bronchi vs. Bronchioles)
Bronchi
- Have cartilage
- Part of conducting system only
Bronchioles (Both)
- Have NO cartilage
- More prominent smooth muscle layer
- Part of conducting system through terminal bronchioles
- Last branches are respiratory bronchioles
- Part of respiratory system
- Give rise to alveoli
Conducting Bronchioles (through terminal bronchioles)
- Respiratory epithelium
- Smooth muscle
- Elastic fibers
- No cartilage
Respiratory Bronchioles
- Directly lead to alveoli
- Smooth muscle
- Elastic fibers
- No cartilage
Cell Types in Respiratory Epithelium
Ciliated cells
- Cilia beat toward pharynx
Goblet cells
- Unicellular mucous glands; secrete mucus
Granule cells
- Endocrine cells
Brush cells
- Have microvilli; chemosensory/associated with nerve ending
Basal cells
- Stem cells
*these cells are contributing to the warming, humidifying and filtering of inspired air
Filtration of Inspired Air
- By entrapment from nasal hairs
- By sedimentation due to gravity in the smaller airways
- Mechanical or chemical stimulation of airway receptors can lead to bronchoconstriction (reduce flow of bad things into body)
- Stimulation of nose or nasopharynx receptors = sneeze
- Stimulation of tracheal receptors = cough
- Activity of the “mucociliary escalator”; cilia
respiratory zone vs. cartilaginous zone
- Respiratory zone is participating in gas exchange
- Conducting zone can’t participate in gas exchange; just transports air down
- Can be referred to as the anatomical dead space (150-200 ml)
Paths of Pulmonary Arteries and Veins through lung
Pulmonary Arteries “segmental”
- follow bronchial tree
Pulmonary Veins (“intersegmental”)
- travel between bronchopulmonary segments
Motor & Sensory Innervation of the Larynx
Vagus Nerve (Cranial Nerve X)
Anatomy of Larynx
- Larynx includes epiglottis and vocal folds
- Cartilage and skeletal muscle
- Vocal folds are on lateral walls
- Lined by respiratory epithelium
- EXCEPT on vocal folds
- stratified squamous epithelium
- Resists high friction from vibration
- EXCEPT on vocal folds
epiglotiis is the lid that covers larynx when we swallow
