Respiratory System - Anatomy

What are the main structures of the respiratory system?

Nose, nasal cavity, paranasal sinuses, pharynx, larynx, trachea, bronchi, lungs, bronchioles, and alveoli

What are the main functions of the respiratory system?

Surface area for gas exchange, ventilation, protect respiratory surfaces, produce sounds, and facilitate sense of smell

What are the 3 definitions of respiration?

External, internal and cellular

What is external respiration?

The exchange of O2 and CO2 between the air and the body’s interstitial fluids “gas exchange at the lungs”

What is internal respiration?

The absorption of O2 and release of CO2 by the body’s cells “gas exchnge at the tissues”

What is cellular respiration?

The process of converting the energy stored in food molecules into a useable form (ATP), requires the presence of O2 and produces CO2 as a waste product

What are the 3 basic requirements of the surface where external respiration occurs?

Moisture, lining of thin cells, a large surge area

What does the majority of our respiratory tract do?

Delivers air to and from the respiratory surfaces, ie. the alveoli and bronchioles

What are the 2 structural divisions of the respiratory system?

Into the upper and lower tracts

What structures are found in the upper respiratory tract?

Nose, nasal cavity, paranasal sinuses, and pharynx

What structures are found in the lower respiratory tract?

Larynx, trachea, bronchi, bronchioles, and alveoli

What are the 2 functional divisions of the respiratory system?

Conducting and respiratory divisions

What is the conducting division of the respiratory system?

The passageways that carry air to and from the surfaces where gas exchange occurs, includes: nasal cavity, pharynx, larynx, trachea, bronchi, and larger bronchioles

What is the respiratory division of the respiratory system?

The structures that have the surfaces where gas exchange occurs, includes: respiratory bronchioles and alveoli

What are the nose, nasal cavity and paranasal sinuses lined by?

Nasal mucosa which consists of pseudostratified ciliated columnar epithelium over top of a basement membrane which is then over top of a layer of lamina propria

What is the purpose of the nasal conchae?

To cause turbulence which ensures that air moves around in the nasal cavity to maximise air exposure to the nasal mucosa

What is the pharynx?

A chamber shared by the respiratory and digestive systems

What are the 3 parts of the pharynx?

Nasopharynx, oropharynx, and laryngopharynx

What is the name of the tube connecting the nasopharynx to the middle ear?

Eustachian tube

What kind of tissue is the pharynx made up of?

Stratified squamous epithelium

What is the glottis?

The opening to the larynx, surrounded by vocal folds

What is the larynx?

The start of the lower respiratory tract, composed of various cartilaginous structures including the epiglottis

What tissue type makes up the epiglottis?

Elastic cartilage

What is the trachea?

The windpipe, a strong and flexible tube

What is the structure of the trachea?

Approximately 2.5cm in diameter, with C-shaped rings of hyaline cartilage to hold it open

Where is the trachea located?

Anterior to the esophagus, connects the larynx and primary bronchi

What is the smooth muscle in the C-shaped rings?

The trachealis, controls the diameter of the opening as needed

What are the C-shaped rings of the trachea made of?

Hyaline cartilage

What are the bronchi divisions?

Primary (main), secondary (lobar), and tertiary (segmental) bronchi

What is the role of the primary (main) R and L bronchi?

Carry air to and from each lung

What is the role of the secondary (lobar) bronchi?

Carry air to and from a lung lobe

Where are the lung lobes located?

3 on the right 2 on the left

What is the role of the tertiary (segmental) bronchi?

Carry to and from a bronchopulmonary segment of a lung

What is a lobe?

The smaller subunits of the lungs separated by fissures

What is a bronchopulmonary segement?

The smaller subunits of a lobe, each lobe has multiple

What is a bronchus?

A tube connected to the trachea that branches into many subsidiaries and provides a passageway for air to enter and leave the lungs

What is a bronchiole?

Branch of the bronchi that are 1mm or less in diameter and terminate at alveolar sacs

What do bronchioles divide into?

1000s of terminal bronchioles

What are the smallest tubes of the conducting respiratory division?

Terminal bronchioles

What tissue type makes up bronchioles and what does it allow?

Smooth muscle, bronchoconstriction and bronchodilation

What are alveoli?

Many tiny sacs where gas exchange occurs

What surrounds the alveoli?

Capillaries

What tissue type is an alveolus made of?

A single layer of epithelium

What allows for the easy diffusion of gasses in the alveoli?

The very thin layer of epithelial tissue found in the alveolus and the capillary it touches

What are the 2 types of alveoli tissues?

Squamous (type I) alveolar cells/Type I pneumocytes and great (type II) alveolar cells/Type II pneumocytes

What is the most common type of alveoli tissue?

Type I pneumocytes, 95%

What tissue type are type I pneumocytes?

Simple squamous epithelium

What tissue type are type II pneumocytes?

Cuboidal epithelium

What is the role of type II pneumocytes?

Secrete pulmonary surfactant

What is pulmonary surfactant?

Substance composed of phospholipid and proteins that reduces the surface tension of the alveoli, lacking in premature babies

What is the respiratory membrane?

Alveolar and capillary wall together, which form an air-blood barrier that facilitates the simple diffusion of gases

What is the respiratory membrane composed of?

Simple squamous epithelium lining of the alveolus and capillary and their shared basement membrane, average of 0.5 micrometers thick