1. Observe the gross morphological structure of the nasal cavity, paranasal sinuses, larynx, trachea, bronchi and lungs.
2. Observe the gross morphologic structure of the pleura, pleural cavity and mediastinum.
3. Observe the microstructure of trachea and lung.
Operation method
Respiratory System Observation Experiment
Materials and Instruments
Head median sagittal specimen and model Skull specimen Larynx anatomical specimen and model Laryngeal cartilage model Trachea Bronchus and lung anatomical specimen and model Anatomical specimen and model Thorax anatomical specimen Trachea Lung tissue section Olfactory epithelium Alveolar wall electron microscope picture Blood-air barrier electron microscope picture Move I. Nasal cavity and paranasal sinuses For more product details, please visit Aladdin Scientific website.
Anatomical disks Anatomical forceps Probes Microscopes
A median sagittal cut specimen of the head was used and observed in conjunction with a cranial specimen.
1. The nasal cavity is divided into two halves, left and right, by the nasal septum. The posterior part of the nasal cavity is connected to the nasopharynx through the posterior nasal aperture. There are three turbinates in the lateral wall of the nasal cavity, which are called the upper turbinate, middle turbinate and lower turbinate. Below each turbinate there are nasal passages, respectively known as the upper nasal tract, the middle nasal tract and the lower nasal tract. The upper and middle nasal passages have openings for the paranasal sinuses, which can be explored with a probe. The anterior part of the inferior nasal passage has the opening of the nasolacrimal duct. The inner surface of the nasal cavity, including the nasal turbinates and nasal passages are lined with mucosa.
2. Paranasal sinuses for the nasal cavity around the skull containing air cavity, there are four pairs, namely, the upper frontal sinus, frontal sinus, pterygoid sinus and sieve sinus. Upper collateral sinus, frontal sinus, sieve sinus of the front group and the group are open in the middle nasal tract; sieve sinus of the back group of openings in the upper nasal tract; pterygoid sinus openings in the lower turbinate of the upper back.
II. Larynx
Observation with isolated laryngeal anatomical specimens and laryngeal cartilage models.
The larynx is based on cartilage, connected by joints, ligaments and muscles.
(I) Cartilage of the larynx
It consists of a single thyroid cartilage, cricoid cartilage, epiglottis cartilage and paired arytenoid cartilages. The thyroid cartilage consists of two square plates fused to each other at the anterior margin, the upper end of the fusion protrudes forward, especially prominent in adult men, called the laryngeal node. The cricoid cartilage lies below the thyroid cartilage and consists of two parts: the cricoid plate and the cricoid arch. The epiglottis cartilage is leaf-shaped and is attached to the inner surface of the thyroid cartilage by a ligament. The arytenoid cartilage is located above the cricoid plate and is trigonous in shape, with the base downward to form a joint with the cricoid cartilage.
(II) Laryngeal muscle
According to their functions, they can be divided into the following two groups of muscles:
1. Muscle groups for opening or narrowing the vocal folds There are cricoarytenoid muscles for opening the vocal folds, and cricoarytenoid muscles and transverse arytenoid muscles for narrowing the vocal folds.
2. Muscle groups for tension and relaxation of the vocal folds The cricoarytenoid muscle is used for tensioning the vocal folds, and the arytenoid muscle is used for relaxing the vocal folds.
Observe carefully the course and origin of the above muscle fibers and relate them to their functions.
(ii) Laryngeal cavity
The lateral wall of the middle laryngeal cavity has two pairs of mucosal folds protruding into the cavity, the upper symmetrical vestibular folds and the lower symmetrical vocal folds. The fissure between the vestibular folds is the vestibular fissure, and the fissure between the vocal folds is the vocal fissure. The vocal folds, along with the vocal ligaments that cover them, and the vocal fold muscle (the muscle bundle of the arytenoid muscle that stops at the vocal fold eminence), form the vocal folds.
Trachea and bronchi
Anatomical specimens of the trachea and bronchi were taken for observation. The trachea consists of 16 ~ ~ 20 semi-circular tracheal cartilage and connective tissue and smooth muscle between the tracheal cartilage, lined with mucosa. The trachea is attached to the cricoid cartilage and descends vertically anterior to the esophagus, entering the thoracic cavity and dividing into the left and right bronchi into the lungs at the plane of the sternal angle. The right bronchus is short and thick, steeper and straighter, almost a direct continuation of the bronchus. The left bronchus is slender and more oblique.
Lungs
Thoracic dissection specimens and free specimens of the lungs were taken for observation.
The left and right lungs are located in the thoracic cavity separated by the mediastinum. The mediastinum is the entire area between the two lungs in terms of the trachea, bronchi, heart, esophagus and large blood vessels in this area.
2. Morphology of the lungs The lungs are roughly conical in shape, with the apex at the top and the base at the bottom. The apices of the lungs protrude towards the base of the neck and are about 2-3 cm above the upper thoracic opening, while the lung bases are located above the septal muscles. There is a depression in the middle of the inner face of both lungs called the hilum. The hilum is the entry and exit point for nerves, blood vessels, lymphatic vessels and bronchi, and is surrounded by many hilar lymph nodes.
The left lung is divided into upper and lower lobes by the oblique fissure, and the right lung is divided into upper, middle and lower lobes by the oblique fissure and the right parafissure. The surface of the lungs can be seen in many polygonal cells, each cell is equivalent to a lobule.
V. Pleura and pleural cavity
Observe with an anatomical specimen of the thoracic cavity.
The pleura is a thin and smooth plasma membrane, divided into two parts: the dirty pleura and the wall pleura. The dirty pleura is close to the surface of the lungs and extends into the interlobar fissures. The mural pleura adheres to the surface of the mediastinum, the inner surface of the chest wall and above the diaphragm. The dirty pleura and the mural pleura migrate towards each other at the hilum. The narrow space between the dirty and mural pleura is called the pleural cavity. Understand the role of the pleura in respiration.
VI. Microstructure of the trachea
Take sections of rabbit trachea (H-E staining) for observation, relate to the function of trachea, understand the general organization of trachea wall and its characteristics.
(I) Low magnification observation
When observed sequentially from the lumen surface outward, the tracheal wall was seen to be composed of mucosa, submucosa and epithelium.
(B) High magnification observation
The epithelium is pseudo-ciliated columnar epithelium. The cilia were clearly visible, and there were a large number of cup-shaped cells in the epithelium. The fibers of the lamina propria are fine and dense, containing abundant elastic fibers, and these fibers are mostly cut into sections on the section, showing red glossy strips or dots. In addition, there are ducts of glands, blood vessels and nerves.
2. The submucosa is a loose connective tissue with mixed glands, which are tracheal glands. This layer has no obvious boundary with the lamina propria.
3. The outer membrane is composed of "C"-shaped hyaline cartilage (tracheal cartilage) and connective tissue. If the section is cut to the notch of the tracheal cartilage, it can be seen that there are some smooth muscle bundles in the connective tissue at the notch.
VII. Microstructure of the lung
Take sections of rabbit and human lungs (H-E staining) for observation. Identify the different structural characteristics of the conduction and respiratory segments of the lung and their relationship to each other's migration.
(i) Low magnification observation
Many honeycomb-like structures of varying sizes, i.e. alveoli, are visible. Also visible are bronchi at all levels (small bronchi, fine bronchi, terminal bronchi, respiratory bronchi) and their accompanying blood vessels. The connective tissue between the two alveoli is the alveolar septum. Look for a section with respiratory fine bronchioles connected to the alveolar ducts, alveolar sacs, and alveoli and change to high magnification.
(ii) High magnification observation
1. The lumen of small bronchial tubes is large, and the luminal surface is covered with pseudo-complex ciliated columnar epithelium. There is an incomplete circular smooth muscle bundle at the junction of the lamina propria and the submucosa. There were glands in the submucosa. There are several pieces of cartilage in the tunica.
2. Fine bronchial tubes The structure is basically similar to that of small bronchial tubes, except that the diameter of the tubes is smaller, and the glands and cartilage gradually decrease, but the smooth muscle increases.
3. Terminal bronchioles The mucosa forms many folds, so the lumen is stellate. The epithelium is a single layer of ciliated columnar epithelium, no cup-shaped cells. Glands and cartilage no longer exist. The outside is surrounded by a thin layer of more complete circular smooth muscle layer.
4. Respiratory bronchial tubes It is different from the terminal fine bronchial tubes is that the wall of the tube has been alveolar, and its wall is directly connected to the alveoli or alveolar ducts. The wall epithelium is a single layer of columnar or cuboidal epithelium, or even a single layer of flat epithelium.
5. Alveolar ducts are branches of respiratory bronchioles, which are surrounded by many alveoli, so they have few wall structures of their own, and the walls exist only in the part between the openings of neighboring alveoli. The epithelial cells here are cuboidal or flattened. The subepithelium contains a small amount of connective tissue and smooth muscle fibers. Its structure is characterized by the formation of a nodular expansion at the edge of the alveolar septum.
6. Alveolar sacs are saccular cavities formed by the common opening of several alveoli. The structure is similar to the alveolar ducts, but there are no smooth muscle fibers at the alveolar openings, so the alveolar septum has no obvious expansion at the end.
7. Alveoli are small hemispherical sacs. The walls of the alveoli are thin and lined with a single layer of flat epithelium. The epithelium consists of type I alveolar cells and type II alveolar cells. Most of the surface of the alveoli lined by type I alveolar cells, the cells are flat, thin, only slightly thick in the nucleus, so it is difficult to see clearly under the light microscope. type II alveolar cells are larger, in the light microscope can be distinguished, the cells were round or cubic, can be protruding from the surface of the alveolus into the cavity, the cytoplasm of the light blue, and some of them are vacuolated.
8. Alveolar septum The thin layer of connective tissue between adjacent alveoli constitutes the alveolar septum. The septum can be seen in the section of many capillaries. In human lung section, alveolar cavity or alveolar septum can be seen in a larger, cytoplasmic black dust particles in the cells, called dust cells. Dust cells may be present singly or in groups of several.
VIII. Demonstrate observation of the following electron microscopic structures
1. Olfactory epithelium Observe with a scanning electron microscope picture. On the surface of the olfactory epithelium, the ends of the dendrites of the olfactory cells can be seen to expand into globules called olfactory vesicles. The olfactory bulb emits 10-30 slender cilia called olfactory hairs. The supporting cells have slender, zigzagging microvilli.
2. Alveolar wall Observed with scanning electron microscope picture. The capillary lumen and alveoli are visible in the cross section, and the capillary wall is zigzagged and convex to the alveolar lumen.
3. Blood-air barrier Viewed with a transmission electron microscope image. Identify structures such as alveolar lumen, alveolar epithelium, basement membrane, endothelial cells, and red blood cells.