Respiratory system Flashcards
Respiratory system components and functions
Components
- Lungs and airway passages
- Pharynx, larynx, Trachea, bronchial tubes.
Function
- Transfer oxygen from inhaled air to blood (external respiration)
- Transfer carbon dioxide from blood to exhaled air.
- Aids in the regulation of acid/base balance of body fluids
- Air flowing out through the vocal cords produces sound.
- Clears the airway, removing of particles
Describe the lungs
- Located within the thoracic cavity
- Spongy
- Cone shaped organs
- Apex
- Broad base
- Costal surface
- Hilum located on mediastinal surface
- 3 borders: anterior, superior and posterior
- Paired
Describe left lung
- smaller
- contains cardiac notch
- 2 lobes: superior and inferior
- Divided by oblique fissure
Describe right lung
- thicker and broader
- 3 lobes: superior, middle and inferior
- Oblique fissure and horizontal fissure
Lungs: Pleural membrane
- Each lung has its own pleural membrane
Consists of 2 layers - Visceral (inner)
- Parietal (outer)
Between the 2 layers is the pleural cavity - Contain pleural fluid- to reduce friction, allows lungs to move as we breathe.
Respiratory system: What is a conducting zone?
series of interconnecting cavities
What is the respiratory zone?
where gas exchange occurs
Upper respiratory tract
- Nose
- Pharyn
Lower Respiratory Tract
- Larynx
- Trachea
- Bronchi
- Lungs
Upper respiratory tract: Nose
Nose has 3 functions.
Warming, moistening and filtering air (membrane has blood vessels running close to surfaces)
- Conchae (ledgers- increase turbulence)
- Respiratory membrane- (consists nucleus, ciliated cells)
- Nasal hair (vibrissae)- Filter out large particles
Detecting smell:
- Olfactory nerves- First cranial nerve
Modifying speech vibration, through resonance
- Paranasal sinuses
Upper respiratory tract: Pharnyx + describe the 3 regions it consists of
Function:
- Passage for: Air, Food.
- Resonating chamber for sound.
- Immunological reactions against foreign invaders.
Nasopharynx
- Superior aspect
- Commences at the posterior aspect of the nasal cavity
Oropharynx
- Middle aspect
- Located behind the oral cavity
Laryngopharynx /Hypopharynx
- Inferior aspect
- Larynx located anteriorly
- Continuous with the oesophagus
Lower respiratory tract: Larnyx
Function:
- Switching mechanism
- Structure of sound production
- Cough mechanism
Structure
-Located between the pharynx and trachea
Consists of 9 cartilages:
-3 paired arytenoid, cuneiform and corniculate
-3 single thyroid, cricoid and epiglottis
-Held together by ligaments
-True vocal cords
-False vocal cords / vestibular folds
Lower respiratory tract: Trachea
Structure
- Tubular passage way providing rigidity and flexibility
Consists of :
- “C” shaped horizontal ring of hyaline cartilage located anteriorly,
- Smooth muscle fibres, Trachealis muscle, Soft connective tissue Posteriorly
- Carina
- Mucous membrane lining
- Submucosa
- Aventitia
Lower respiratory tract: Bronchi
- Secondary (Lobular) bronchi
- Tertiary (Segmental) bronchi
- Continue branching approximately 23 orders.
Bronchioles - Terminal Bronchioles
- Respiratory Bronchioles
- Left and right primary bronchi
Differences
Right primary bronchus
- is more vertical
- Shorter
- Wider
- Divide into secondary bronchi one for each lobe.
- Divide in to tertiary (segmental) bronchi
- All bronchi have cilia and goblet cells present and cartilage.
Lower respiratory tract: Bronchioles
Main function is for gas exchange (external)
- Airways less than 1 mm in diameter
- have no cartilaginous support replaced by smooth muscle.
- ciliated epithelium is replaced by non-ciliated epithelium
Terminal Bronchioles
- limited ciliated cells, no goblet cells
Respiratory Bronchioles
- cuboidal epithelium
- Branch to form alveolar ducts
Lower respiratory tract: Alveoli
- microscopic
- protrude from the end of the alveolar ducts
- groups of alveoli called alveolar sacs
- composed of a single layer of cells
- alveoli form huge surface area (estimated 70 m2)
- surrounded by pulmonary capillaries
- Alveolar pores – connect adjacent alveoli equalize air pressure
- contain alveolar macrophages
- Site of external respiration
Muscles of respiration: What does the diaphragm do?
- Separates thoracic and abdominal cavities
- Dome shaped
- Main muscle of respiration: Contracts and flattens in inspiration, Relaxes in expiration, Supplied by the phrenic nerve
Muscles of respiration: Intercostal muscles (in between ribs)
External intercostal
- Located between ribs
- Contracts in inspiration
- Relaxes in expiration
Internal intercostal
- Located between ribs
- Contracts in forceful expiration
What type of process is inhalation classed as?
Active
What type of process is exhalation classed as?
passive
Mediastinum
- Located in the thoracic cavity.
- Between the medial aspects of the two lungs and pleura
- Superior mediastinum
- Inferior mediastinum
Anterior mediastinum
Middle mediastinum
Posterior mediastinum
Contains: - heart, vessels, trachea, oesophagus and nerves.
Control of respiration
Respiratory centres located in:
- Medulla oblongata
- Pons
Phrenic nerves (to diaphragm)
External intercostal nerves (to external intercostal muscles
Chemoreceptors
- Central
- Peripheral
