Respiratory System Flashcards
What is in the upper respiratory tract?
Nose, Pharynx and Larynx
What is in the lower respiratory tract?
Trachea, Bronchi, Bronchioles and Alveoli
What is the role of the upper respiratory tract?
- Warms
- Humidifies
- Secretes lysozyme
- Filters and moves dust laden mucus to the pharynx
What is the role of the nose?
In addition to respiration the nose is a resonating chamber fro speech and houses the scent receptors
What are the 3 bones in the nose extending from the cavity wall?
Superior, middle and inferior nasal conchae
What happens in the nasal cavity?
Air swirls around to enhance filtering, warming and wetting on inhalation and reverse these processes on exhalation
What is the pharynx?
Tube of skeletal muscle which starts at the internal nares and extends to the level of the 6th cervical vertebrae
What does the pharynx act as?
- A passageway for both food and air
- Houses the tonsils
- Acts as a resonance chamber for sounds
What are the 3 divisions of the pharynx?
- Nasopharynx
- Oropharynx
- Laryngopharynx
What does the nasopharynx connect to?
With the middle ear via the left and right eustachian tubes which equalise pressure to prevent damage to the ears
What is the nasopharynx?
It is blocked by the soft palate and uvula during swallowing. It is lined by pseudostratified epithelium which wafts mucus dust packages to the mouth
What is the oropharynx?
It is lined by resilient stratified squamous epithelium. This contains the pair of palatine tonsils and the lingual tonsils
What is the laryngopharynx?
It is lined with stratified squamous epithelium. It connects with both the oesophagus and larynx
What is the larynx?
Cartilaginous tube lined with mucus membrane anterior to vertebrae C4 - C6
What are the pieces of cartilage that form the laryngeal box?
- Epiglottis
- Thyroid cartilage (Adams apple)
- Cricoid cartilage (Anchor for trachea)
What is the laryngeal box?
Voice box
What are the internal laryngeal muscles?
Control coal cord length and tension
What are the external laryngeal muscles?
Control movement of whole larynx up and down
What is the trachea?
Lined with mucous ciliated membranes. Divides into 2 main bronchi and is very flexible and mobile. Supported by 16 - 20 C shaped bands of cartilage which allows expansion into the trachea when swallowing
In the lungs what do the main bronchi divide to form?
Lobar bronchi then segmental bronchi then bronchioles
What are the lungs covered by?
Pleura
How many lobes does the right lung have?
3
How many lobes does the left lung have?
2 and is 10% smaller
What are the 2 major types of epithelial cells that form the walls of alveoli?
- Type 1 = for gas exchange
- Type 2 = secretes surfactant
What is pulmonary ventilation?
Movement of air in and out of the lungs so that gases in the alveoli are continuously changed and refreshed
What is inspiration?
Development of a negative pressure within the chest to allow air to flow in down a pressure gradient into the lungs
What is expiration?
Thoracic volume decreases which increases intrathoracic pressure and air flows out
What is external respiration?
Occurs at the alveoli. Oxygen diffuses from the air in the alveoli to the blood in the pulmonary capillaries because P02 is higher in air than in the deoxygenated blood. Independently CO2 diffuses in the opposite direction
What is internal respiration?
Occurs between the blood in the capillaries and tissue cells throughout the body. This happens because of differences in the partial pressures of the gases
How is oxygen transported?
98.5% is carried by erythrocytes as oxyhaemoglobin. When P02 is high oxyhaemoglobin binds tightly together and becomes saturated. When PC02 or temperature rises haemoglobin releases oxygen more readily
How is carbon dioxide transported?
7% dissolves in plasma. Proteins in the blood pick up and carry another 23%. Mostly carried as carbaminohaemoglobin. The majority (70%) combines with water to form carbonic acid which separates into the hydrogen and bicarbonate ions
Where is the control of respiration?
Control primarily lies with neurones in the in the reticullar system of the medulla and pons.
What does the medulla oblongata include?
The ventral respiratory group (VRG) and the dorsal respiratory group (DRG)
What do the pons include?
The pontine respiratory group (PRG)
What does the ventral respiratory group do?
Autorhythmically stimulates spontaneous ventilation
What does the dorsal respiratory group do?
Responds to situations beyond those of resting breathing to alter the pattern for ventilation in respond to the physiological needs of the body
What is reduced oxygen content in the blood called?
Hypoxia
What is the rate and depth of breathing is mainly influenced by?
Changes in PC02, P02 and pH
