Special cells in the alveolus wall secrete a detergent like chemical on to the inside lining of the alveolus called surfactant. It lowers the surface tension to reduce force needed to inflate lungs and also kill any bacteria present in the alveoli

Laryngopharynx is located inferior to all parts and it is also the Posterior most part.

Left bronchus is longer than right bronchus while right bronchus has larger diameter than left one.

1. Tidal Volume (TV): The volume of air inspired or expired during normal breathing. Typical value: around 500 mL.
2. Inspiratory Reserve Volume (IRV): The additional volume of air that can be inhaled with maximum effort after a normal inspiration. Typical value: around 3000 mL.
3. Expiratory Reserve Volume (ERV): The additional volume of air that can be exhaled with maximum effort after a normal expiration. Typical value: around 1200 mL.
4. Residual Volume (RV): The volume of air remaining in the lungs after maximum expiration. Typical value: around 1500 mL.

Voice is produced when air pass through two ligaments called vocal cords present in larynx.

The pitch and volume of sound produced varies with the amount of tension on the vocal cords and on the amount of air being forced past them. When amount of air is same then it only depends on Tension.

Right lung has 3 lobes and has greater volume (56%) while the left one has 2 lobe and (46%) of the total volume.

Trachea is wind pipe between larynx(specifically cricoid cartilage) and carina(see next question).

Oropharynx is the middle part of Pharynx. It is involved in both phases of swallowing.

1. Medullary Respiratory Center: Located in the medulla oblongata of the brainstem, it consists of two main groups of neurons:
a. Inspiratory Centre: Primarily responsible for inspiration. primary centre.
b. Expiratory centre: Involved in both inspiration and expiration, but primarily active during forced expiration.
2. Pon Respiratory Group (PRG): Located in the pons, it helps regulate and fine-tune the breathing pattern by influencing the medullary respiratory centers.

Larynx is also called Glottis

1. Pericardium: Double-layered membrane surrounding the heart.
2. Capsule: Tough, fibrous layer surrounding a structure, such as a joint or organ. i-e renal capsule
3. Perimysium: Connective tissue surrounding groups of muscle fibers.
4. Pleura: Double-layered membrane surrounding each lung and lining the chest cavity.

1. Simple Squamous Epithelium: This is a single layer of flat cells. It is often found in areas where diffusion or filtration occurs. For example, it lines blood vessels and air sacs of lungs.
2. Ciliated Squamous Epithelium: This is a type of epithelial tissue that consists of a single layer of flat cells (squamous cells) with cilia on their surface. Ciliated squamous epithelium is found in the lining of certain parts of the respiratory tract, where the cilia help to move mucus and trapped particles out of the airways.
3. Simple Cuboidal Epithelium: This is a single layer of cube-shaped cells. It is found in areas where secretion and absorption take place. For example, it lines the kidney tubules and ducts of certain glands.
4. Ciliated Cuboidal Epithelium: This is a type of epithelial tissue that consists of a single layer of cube-shaped cells (cuboidal cells) with cilia on their surface. Ciliated cuboidal epithelium is less common than ciliated columnar epithelium but can be found in certain parts of the respiratory and reproductive systems where cilia help to move substances along the surface of the epithelium.

Bronchi have same structure as trachea although they contains cartilaginous rings in proximal part which are progressively replaced by cartilaginous plates in the distal part.

A point where trachea divides into Bronchi

1. Moist Squamous Epithelium: This is a single layer of flat cells. It is often found in areas where diffusion or filtration occurs. For example, it lines blood vessels and air sacs of lungs.
2. Ciliated Squamous Epithelium: This is a type of epithelial tissue that consists of a single layer of flat cells (squamous cells) with cilia on their surface. Ciliated squamous epithelium is found in the lining of certain parts of the respiratory tract, where the cilia help to move mucus and trapped particles out of the airways.
3. Simple Cuboidal Epithelium: This is a single layer of cube-shaped cells. It is found in areas where secretion and absorption take place. For example, it lines the kidney tubules and ducts of certain glands.
4. Ciliated Cuboidal Epithelium: This is a type of epithelial tissue that consists of a single layer of cube-shaped cells (cuboidal cells) with cilia on their surface. Ciliated cuboidal epithelium is less common than ciliated columnar epithelium but can be found in certain parts of the respiratory and reproductive systems where cilia help to move substances along the surface of the epithelium.