- The major organs/parts of body that are involved in
respiration
1. Nose/Nasal cavity
Filters, warms, and moistens air. 2 portions: external (nose) and Internal
(nasal cavity) – composed of bone and cartilage.
The bony part – frontal, nasal and maxillae bones
The cartilage part – septal, lateral, and alar cartilages (contains mucus-
secreting cells)
Anterior nares (nostrils) are the openings of the nasal cavity. The septum
divides the nasal cavity into two halves.
2. Pharynx (Throat)
Passageway for air and food. Funnel shaped and posterior to the nasal
cavity.
Nasopharynx (1st), Oropharynx (2nd), Laryngopharynx (3rd)
3. Larynx (Voice box)
Air passageway and voice production. Hollow structure that is connected
to the top of the trachea.
4. Epiglottis
Large leaf-shaped piece of cartilage – closes the tracheal opening during
swallowing of food to prevent food entering trachea.
5. Trachea (windpipe)
Air conduction. C-shaped cartilage rings keep it open. Divides into smaller
structures – bronchi, terminal bronchioles, respiratory bronchioles.
6. Bronchi and Bronchial tree
Extends into the lungs. Left – 2 secondary bronchioles – 8 Tertiary
bronchioles Right – 3 secondary bronchioles – 10 tertiary bronchioles
7. Lungs
Contains the alveoli (site of gas exchange)
, - The gross anatomy and function of each region of
respiratory system
Conducting Zone: Cleanse, humidify, and warm incoming air (nose,
pharynx, larynx, trachea, bronchi, and terminal bronchioles)
Respiratory Zone: Site of gas exchange (respiratory bronchioles,
alveolar ducts, and alveoli)
Alveoli: Tiny air sacs; walls are mainly a single layer of type 1 cells
(Squamous epithelial - 95%) and have scatter type 2 cells (secrete
surfactant to reduce surface tension – 5%)
- Normal respiratory process including the cellular
component (between blood and tissues)
Respiration involves four processes:
1. Pulmonary Ventilation (Breathing): Movement of air into
(inspiration) and out of (expiration) the lungs.
Inspiration: Diaphragm contracts – thoracic volume increases – lung
pressure decreases – air flows in
Expiration: Diaphragm relaxes – thoracic volume decreases - lung
pressure increases – air flows out
2. External Respiration: Gas exchange between the lungs (alveoli)
and the blood. Oxygen moves from the alveoli to the blood, and
carbon dioxide moves from the blood to the alveoli.
3. Transport of Respiratory Gases: Oxygen transported bound to
haemoglobin on red blood cells. Carbon dioxide transported mostly
as bicarbonate ion in plasma.
4. Internal Respiration: Gas exchange between the blood and the
tissues. Oxygen moves from the blood to the tissues and carbon
dioxide moves from the tissues to the blood.
- Basics of lung volumes and pulmonary function tests
Pulmonary Function Test: Group of non-invasive tests that assess how
well the lungs work. These tests can measure lung volume, capacity, flow
rates, and gas exchange. It can be used to diagnose and monitor
respiratory conditions.
Spirometry: Measure the amount of air a person can inhale and exhale,
also the rate at which air is exhaled from the lungs.
Forced Vital Capacity (FVC): The maximum volume of air a person can
forcefully exhale from their lungs after taking a maximal deep breath.