Lower respiratory tract Flashcards
Pleurae
fluid-filled (serous) sacs that surround each lung.
Visceral pleura
part of pleura covering lungs
Parietal pleura
part of pleura not covering lungs
adjacent to body wall
Pleural cavity
Potential space between parietal and visceral layers filled with a small amount (20 ml) of serous fluid.
Pressure of pleural cavity is always _____ than
atmospheric pressure.
lower
Collapsed lung (pneumothorax)
Because there is low pressure within the pleural cavity, air or
liquid will readily enter this space. This increases the
pressure of the pleural cavity, causing the lung to collapse
due to it’s inherent elasticity.
lungs separated by
mediastium
lobes of lung
right = 3 lobes (superior, middle, inferior) left = 2 lobes (superior, inferior)
lung lobes are separated by ____
fissures (oblique, horizontal)
Hilum
located on the mediastinal surface of each lung.
It is where the parietal and visceral pleura meet, and all
structures enter and exit the lung.
Structures at hilum (3)
Pulmonary arteries
Pulmonary veins
Air passages (bronchi)
Pulmonary Emboli
•Most (95%) originate in deep leg veins.
•Causes: stasis (bed rest), trauma, or
coagulation disorders.
• Symptoms: dyspnea, lightheadedness, tachycardia
Consequences of a large capillary bed
Pulmonary Emboli, Metastasis
Metastases:
about 30% of malignant tumors
originating outside of lung get lodged in, and hence
invade into, the lung.
• Include salivary gland, thyroid, breast, kidney, colon,
uterine, bladder, ovarian, and prostate.
The Bronchial Tree
Trachea Primary (main) bronchi Secondary (lobar) bronchi Tertiary (segmental) bronchi ~Conducting bronchioles~ Terminal bronchioles Respiratory bronchioles Alveoli
Trachea
- C-shaped cartilaginous rings.
- Posterior part has no cartilage. Replaced by trachealis muscle (adjacent to esophagus)
- Ridge of cartilage at inferior aspect of trachea = carina.
- Splits into primary bronchi.
Primary Bronchi
- One to each lung. Enters lungs at hilum. Contains cartilage like trachea.
- Right bronchus: shorter, wider,and more vertical vs left.
Secondary (Lobar) Bronchi
- Each lobe is supplied by a secondary bronchus.
* Three in right lung, Two in left lung
Tertiary (Segmental) Bronchi
• Each lung has 10 tertiary bronchi.
• Each tertiary bronchus supplies a bronchopulmonary segment: an anatomical unit with own pulmonary
artery and tertiary bronchus.
• Can surgically resect while leaving other segments intact.
bronchopulmonary segment
an anatomical unit with own pulmonary
artery and tertiary bronchus.
Bronchioles:
loss of cartilage, gain of smooth muscle.
Many divisions until reach terminal bronchioles (end of
conducting zone).
Respiratory zone includes respiratory bronchioles and alveoli.
External respiration
O2 diffuses from alveolus to capillary; CO2 diffuses from capillary to alveolus.
Emphysema - COPD
Damage to alveolar walls & loss of lung elasticity.
Difficulty breathing, cannot exhale completely.
Barrel chested.Culprit: tobacco smoke, pollutants, mining.
Parasympathetic on airway
smooth muscle contraction = bronchial constriction, mucus secretion
Sympathetic on airway
smooth muscle relaxation = bronchial dilation
Asthma
Bronchospasm, inflammation causing bronchiole constriction
Constricted bronchiole, mucus secretion
Many inhalers act by simulating the sympathetic nervous system to cause bronchodilation and reduce mucus secretion
the diaphragm is located between
thoracic and abdominal cavities.
Contraction of the diaphragm
(flattening of the parachute)
increases volume of thoracic cavity (inspiraton).
Relaxation of the diaphragm
(passive) resumes its parachut shape, and decreases volume of thoracic cavity (expiration).
Hiccups - synchronous diaphragmatic flutter
Involuntary, spasmodic contractions of the diaphragm, interrupted by closure of the rima glottitis (voice box).
