Nakamura Human Anatomy Ch 22 Flashcards
(21 cards)
Organs of the respiratory system are divided into:
Conducting zone: air passes through (nose/ nasal cavity etc)
Respiratory zone: functional structure, gas exchange oxygen for carbon dioxide and vice versus
Uvula
Problem in old people
Blocks food/ drink from entering lungs
Larynx
.Three functions
–Voice production
–Provides an open airway
–Routes air and food into the proper channels
Bronchi in the conducting zone
- bronchial tree
- primary bronchi (main bronchi)
- right main bronchi
- secondary (lobar bronchi)
- tertiary (segmental) bronchi
- bronchioles
- terminal bronchioles
Bronchial tree
Extensively branching respiratory passageways
Primary bronchi
Main bronchi
Largest bronchi
Right main bronchi
Wider and shorter than the left
Food drops more easily on this side
Secondary bronchi
Lobar
Three lobes on right
Two lobes on the left
Tertiary bronchi
Segmental
Branch into each lung segment
Bronchioles
Little bronchi, less than 1 mm in diameter
Terminal bronchioles
Less than .5 mm in diameter
Respiratory organs
-Nose, nasal cavity, and paranasal sinuses
–Pharynx, larynx, and trachea
–Bronchi and smaller branches
–Lungs and alveoli
Conducting zone
Air conduction
Do not have gas exchanges
Just for air to pass through
From mouth/nose to terminal bronchioles
Changes in tissue composition along conducting pathways
Cartilage changes
–Cartilage rings replaced by cartilage plates as main bronchi enter the lungs
•Epithelium
–First, pseudostratified ciliated columnar
–Replaced by simple columnar, then simple cuboidal epithelium in the terminal bronchioles
•Smooth muscle becomes important
The respiratory zone
Consists of air-exchanging structures
•Respiratory bronchioles: branch from terminal bronchioles (start of respiratory zone)
–Lead to alveolar ducts
•Lead to alveolar sacs
•Simple cuboidal epithelium in the respiratory bronchioles
-Alveoli consist of type I cells and basal laminae
•Scattered among type I cells
–Cuboidal epithelial cells: type II cells
•Secrete surfactant (chemical necessary for alveoli without it alveoli will collapse and cannot have respiration)
The pleurae
A double-layered sac surrounding each lung
–Parietal pleura: surround pleural cavity
–Visceral pleura: cover surface of lung
•Pleural cavity
–Potential space between the visceral and parietal pleurae
•Pleurae help divide the thoracic cavity
–Central mediastinum
–Two lateral pleural compartments
Blood Supply and innervation of the lungs
Pulmonary arteries: deliver oxygen-poor blood to the lungs
•Pulmonary veins: carry oxygenated blood to the heart
•Innervation (autonomic ns)
–Sympathetic, parasympathetic, and visceral sensory fibers
•Parasympathetic: constrict airways
•Sympathetic: dilate airways.
Mechanisms of ventilation
Two phases of pulmonary ventilation
–Inspiration: inhalation
–Expiration: exhalation
Inspiration
Volume of thoracic cavity increases
–Decreases internal gas pressure
–Action of the diaphragm: diaphragm flattens (goes down)
–Action of intercostal muscles: contraction raises the ribs
Expiration
.Quiet expiration – chiefly a passive process
–Inspiratory muscles relax
–Diaphragm moves superiorly
–Volume of thoracic cavity decreases
-ribs go down, internal obliques contract and pull ribs down
Neural control of ventilation
.Respiratory center: generates baseline respiration rate
–In the pons and medulla
•Chemoreceptors: sensitive to rising and falling oxygen levels
–Central chemoreceptors: located in medulla
–Peripheral chemoreceptors
•Aortic bodies
•Carotid bodies
