Anatomy of the Human Respiratory and Digestive Systems
Pharynx
The pharynx is a composite input formed by the nasopharynx, oropharynx, and laryngopharynx. It is formed by musculoskeletal tissue and lined by mucous. It is a channel without anterior muscle, located in front of the cervical vertebrae, measuring 14 to 15cm. The pharynx goes to the 6th cervical vertebra.
Pharyngeal Muscles
- Superior constrictor
- Middle constrictor
- Inferior constrictor
Larynx
The larynx has a respiratory function and is located between C3 and C6. It is an odd, symmetric, and superficial organ.
Paired Cartilages
- Arytenoid
- Cuneiform
- Corniculate
Unpaired Cartilages
- Epiglottis
- Thyroid
- Cricoid
Trachea
The trachea is the continuation of the larynx, located between C6 and T6. It consists of 16 to 20 C-shaped cartilaginous rings. It is positioned posteriorly to the esophagus and is 15 cm in length.
Trachea Layers
- Mucosa
- Submucosa
- Hyaline cartilage
- Adventitia
Bronchi
Right Primary Bronchus
The right primary bronchus is shorter, more vertical, and of a larger caliber than the left. It passes behind the superior vena cava and forms the first branching into the superior, middle, and inferior lobar bronchi.
Left Primary Bronchus
The left primary bronchus is more horizontal, longer, and of a smaller caliber than the right (5 cm). It passes in front of the esophagus and below the aortic arch.
Pleura
Visceral Pleura
The visceral pleura is part of the surface of the lung. It is thin and transparent.
Parietal Pleura
The parietal pleura lines the inside of the thoracic cavity. It has three parts: costal, diaphragmatic, and mediastinal, and a cervical portion.
Pleural Recesses
These are the fornices formed by the pleura:
- Costodiaphragmatic recess
- Vertebromediastinal recess
- Phrenicomediastinal recess
Lungs
Weight: 600g for the right lung and 500g for the left lung. Color: Pink, mottled gray, or dark red. They are soft, elastic, and spongy in appearance, with a smooth and shiny surface, and a flaccid and elastic consistency.
Parotid Gland
The parotid gland’s function is the secretion of saliva. It is the most voluminous salivary gland, weighing approximately 25g, and has a lobulated, yellowish-gray appearance. It is located in the parotid-masseteric region, behind the branch of the jaw.
Parotid Papilla
The parotid duct enters the oral vestibule through a foramen at the second molar, known as the parotid papilla.
Teeth
There are 8 incisors, 4 canines, and 8 molars, totaling 20 to 36 teeth. They are accessory digestive organs located in the alveolar processes of the maxilla and mandible.
Crown
The crown is covered with enamel and projects into the oral cavity.
Neck
The neck is the narrowing where the gum attaches.
Tongue
The tongue is an accessory digestive organ. It presents intricate muscles and is related to chewing, swallowing, taste, and phonation.
Esophagus
The esophagus is 25cm long, and the cervical portion is the widest (5cm). It is located just behind the trachea and extends from the pharynx to the stomach. It secretes mucus.
Esophageal Constrictions
- At the beginning
- The aortic arch crossing
- The left primary bronchus
- When passing through the diaphragm
Stomach
The stomach is 25cm long and has a capacity of 1500ml.
Stomach Regions
- Cardia
- Fundus
- Body
- Pylorus
Stomach Muscle Layers
- Outer longitudinal
- Middle oblique
- Inner circular
Peritoneum
The peritoneum is a tunic shaped like an apron that prevents the abdominal contents from falling out. It is the largest mucous membrane in the body and has parietal and visceral walls.
Components of the Peritoneum
- Greater omentum
- Falciform ligament
- Lesser omentum
- Mesocolon
Parietal Wall
The parietal wall continuously covers the anterior abdominal wall.
Visceral Wall
The visceral wall covers some organs in whole or in part.
Lesser Omentum
The lesser omentum relates to the lesser curvature of the stomach.
Greater Omentum
The greater omentum relates to the greater curvature of the stomach.