1. Observe specimens and sections of the eye to understand the gross anatomy and microstructure of the eye.
2. Observe the parafoveal organs of the eye - eyelids, conjunctiva, lacrimal apparatus and ocular muscles.
3. Observe ear specimens and sections of the inner ear to understand the gross anatomy of the ear and the microstructure of the inner ear.
4. Observe skin sections to understand the microstructure of the skin and its appendages.
5. Demonstrate observation of electron microscopic pictures of the retina, the outer segmental membrane disk of the optic rod cells and the spiral apparatus.
Operation method
Sensory organs and skin anatomy observation experiment
Materials and Instruments
Pig's eye Bovine eyeball Monkey's eyeball anatomical specimen Eyeball model Lacrimal apparatus anatomical specimen Temporal bone dissection specimen Inner ear specimen Inner ear anatomical model Horizontal section of the eyeball Longitudinal section of the cochlea Vertical section of the human scalp Optic rod surface of retinal optic cells electron microscope Pictures of optic rod surface of retinal optic cell Optic rod surface of retina Pictures of outer segmental disc of optic rod Pictures of helical apparatus Pictures of electropheromograms Move I. The general anatomy of the eye For more product details, please visit Aladdin Scientific website.
Blades Dissecting forceps Dissecting disks Mirrors Microscopes
Take a pig or cow eyeball for dissection, and observe it in combination with the human eyeball model and the monkey eyeball anatomical specimen. Use a razor blade to cut the eyeball into anterior and posterior halves, observe the posterior half first, then the anterior half.
(i) The posterior half of the eyeball identifies the following structures from the inside out:
1. vitreous body is a transparent gelatinous substance that fills the eyeball.
2. Retina The retina can be seen when the vitreous humor is removed. It is the innermost white membrane of the eye wall and can be easily peeled away. The macula and the central sulcus can be seen clearly when compared to a demonstration specimen of monkey eye anatomy.
The optic disk is a white circular bulge in the posterior part of the retina.
4. Choroidal membrane The dark brown film seen after tearing off the retina is the choroidal membrane. This membrane is rich in pigment cells and blood vessels.
5. Sclera The outermost layer of the wall of the eyeball left after removal of the choroid is the sclera, which is white, thick and tough.
(b) Identify the following structures from the front half of the eyeball from back to front:
1. Lens Located between the iris and the vitreous humor, the lens is a biconvex hyaloid with a flat front and a convex back.
2. Ciliary body The ciliary body is a ring-shaped thickened portion of the anterior part of the choroid. In the anterior part of the ciliary body, there are dozens of ciliary protrusions protruding medially and arranged in a radial pattern.
3. Small ciliary bands The lens is carefully removed. When the lens is removed, a close look reveals some filamentous fibers, the ciliary bands, which suspend the lens from the ciliary processes.
4. Iris After removing the lens, you can see the iris, which is the most anterior part of the vascular membrane of the eyeball wall. The hole in the center of the iris is the pupil.
5. cornea is the outer membrane of the eye wall of the first 1 / 6 of the transparent membrane, slightly convex forward.
6. The eye chamber is the cavity between the cornea and the lens, divided into anterior and posterior chambers with the iris as the boundary. In vivo, the atrium is filled with aqueous humor.
Second, ocular collateral organs
(I) Eyelids
It is a fold of skin that protects the eyeball, commonly known as the "eyelid", and is divided into the upper and lower lids.
(ii) Conjunctiva
The conjunctiva is a thin, transparent mucous membrane that lines the inner surface of the eyelid. The conjunctiva moves to the bulbar conjunctiva, which is attached to the front of the eyeball. The two migrating parts are called the conjunctival vault, which can be divided into the supraconjunctival vault and the subconjunctival vault. Both of these structures can be observed in a mirror or by classmates with each other.
(iii) Lacrimal apparatus
Demonstrate observation of the components of the lacrimal apparatus using anatomical specimens and models of the lacrimal apparatus.
The lacrimal gland is located in the lacrimal fossa above the orbit and its excretory duct opens into the superior conjunctival vault.
The tear duct is located in the supraorbital fossa, and its excretory duct opens into the superior conjunctival vault. 2. Tear point There is a small hole at the medial end of each of the upper and lower lid margins of the eye.
The lacrimal sac is a membranous sac located in the lacrimal fossa on the medial wall of the orbit, the upper end is blind, and the lower end opens through the nasolacrimal duct into the lower nasal passage.
4. Lacrimal duct is the part connecting the lacrimal punctum and the lacrimal sac, divided into upper and lower lacrimal ducts, both opening in the upper part of the lacrimal sac.
(D) Extraocular muscle
Demonstrate the six muscles that move the eyeball.
The superior, inferior, internal, and external rectus muscles all start in the ring of the common tendon around the optic foramen and end anteriorly at the superior, inferior, internal, and external sides of the eyeball, respectively. The superior oblique muscle originates in the common tendon ring and travels anteriorly between the superior and medial rectus muscles, ending at the superior lateral aspect of the eye. The inferior oblique muscle originates in the infraorbital wall and stops posteriorly posterolateral to the underside of the eye.
III. Microstructure of the eyeball
Horizontal sections (H-E stained) of the dog or human eyeball were taken, and the structures of the various parts of the wall of the eyeball were first differentiated by the naked eye, and then observed under the microscope:
(i) Low magnification observation
The structural features of the various parts of the eyeball were further distinguished under low magnification.
(ii) High magnification observation
Focusing on the structure of the retina, it can be seen that it is divided into 10 layers from outside to inside:
1. Pigment epithelial layer is immediately adjacent to the arterial membrane and consists of a single layer of dwarf cubic pigment ___ epithelial cells. The nucleus is round and centered in the cell. The nucleus is rounded and in the center of the cell. In the cytoplasm of some cells, tiny melanin granules can be seen.
2. Cone and rod layer The cones and rods are the protrusions of cone and rod cells, which are stained red on the section. In the H-E stained section, it is not possible to distinguish between the optic rod and the optic cone.
The outer membrane is a reddish colored thread-like structure on the section.
The outer nuclear layer, where the nuclei of the cone and rod cells are located, is a thick layer stained dark blue on the section, and the two types of nuclei are densely packed together and indistinguishable.
The outer reticular layer is a reddish colored layer interspersed with blue nuclei.
6. The inner nuclear layer is where the nuclei of bipolar cells are located, also stained blue, but the nuclei are larger, slightly sparsely arranged, and lighter in color than the outer nuclear layer.
7. The inner reticulum layer is a layer that is also colored red.
8. Arthrocyte layer In this layer, you can see scattered, large and round, lightly stained nuclei, the nucleus of the arthrocyte.
9. Optic nerve fiber layer is stained red on the section and contains crisscrossed fibers.
10. The inner boundary membrane is the innermost membrane stained red, and also appears as a line-like structure on the section.
The above 10 layers are mainly composed of four layers of cells, from the outer to the inner pigment epithelium, cone and rod cells, bipolar cells and ganglion cells.
Four, the general anatomy of the ear
Ear model, temporal bone dissection specimen, inner ear specimen and inner ear model were taken to observe the middle and inner ear ministries.
(i) Middle ear
The middle ear consists of the tympanic chamber, the eustachian tube and the mastoid process. At the junction of the outer ear and the middle ear, there is an oval membrane, which is called the tympanic membrane.
1. The tympanic cavity is a small cavity within the rocky part of the temporal bone. There are two holes in the lateral wall of the tympanic membrane, the upper hole is the vestibular window, and the lower hole is the cochlear window. The anterior wall of the tympanic cavity has an opening for the eustachian tube. Inside the tympanic cavity there are three auditory ossicles, the hammer bone, the anvil bone and the stapes bone. They are interconnected by joints. The stalk of the hammer bone is attached to the inner surface of the tympanic membrane, and the base of the stapes bone closes the vestibular window.
The Eustachian tube is a tube that connects the tympanic cavity to the nasopharynx, and its two ends open into the anterior wall of the tympanic cavity and the lateral wall of the nasopharynx, respectively.
3. The mastoid process is a series of small air-containing cavities in the mastoid process of the temporal bone. These small cavities are interconnected and eventually pass into a larger cavity that opens forward into the posterior wall of the tympanic cavity.
(ii) Inner ear
It is divided into two parts: the osseous labyrinth and the membranous labyrinth.
The osseous labyrinth is divided into the vestibule, the osseous semicircular canal and the cochlea, which are connected to each other.
(1) vestibule in the middle of the bone labyrinth, for the irregular cavity. Its outer wall is the inner wall of the tympanic cavity, on which there are vestibular window and cochlear window. Posteriorly there are five small holes that pass into the three osseous semicircular canals. Anteriorly, a larger hole leads into the cochlea.
(2) Bone semicircular canals Located in the posterior part of the bone labyrinth, there are three bone semicircular canals, anterior, posterior, and posterior, vertically aligned with each other. Each bony semicircular canal communicates with the vestibule through two bony feet, one of which has an enlarged part called the bony potbelly. The posterior and anterior bony semicircular canals without the pot-bellied end are united into a common foot, so that the three bony semicircular canals have only five holes opening into the vestibule.
(3) the cochlea for the bone labyrinth anterior part, shaped like a snail shell is made of a snail spiral tube around the snail axis curled two and a half weeks into the snail, the top of the snail towards the front of the outside, for the blind end. The bottom of the cochlea faces backward and inward, and the mouth of the tube opens into the vestibule. The middle axis of the cochlea is the cochlear axis, and a cross-section of the cochlea from the top of the cochlea to the bottom of the cochlea is made in a near-horizontal position, which shows the white cochlear axis extending into the cochlea in the form of a spiral piece of bone called the bone helix plate, which doesn't reach the lateral wall of the tube.
2. Membrane labyrinth is a closed continuous membranous tubule and capsule hanging in the bone labyrinth, which can be divided into ellipsoidal capsule and balloon capsule, membranous semicircular canals, and cochlear ducts.
(1) Elliptic capsule and balloon Located in the vestibule. The elliptic bursa is posterior and superior and communicates with the three membranous semicircular canals. The balloon is anteriorly and inferiorly connected to the cochlea by a connecting duct at its lower end. The ellipsoid bursa is connected to the balloon by the ellipsoid balloon canal, which extends upward into the endolymphatic duct and enlarges at the end into the endolymphatic sac. On the floor and anterior wall within the ellipsoid bursa there are ellipsoid bursal spots, and on the anterior wall within the ball sac there are bulbous spots, which are sitoreceptors.
(2) Membranous semicircular canals Similar in shape to the bony semicircular canals, but with a smaller diameter. The membranous jugular wall has a jugular ridge on its inner surface, which is also a bitemporal receptor.
(3) The cochlea is a membranous tube in the cochlea, which also rotates in two and a half weeks. Both ends of the tube are blind, starting at the vestibule and ending at the cochlear apex. The cochlea is connected to the bone spiral plate, thus dividing the cochlea into an upper vestibular order and a lower tympanic order, which are connected at the foramen ovale.
V. Microstructure of the inner ear
(i) Longitudinal section of the cochlea of a guinea pig (H I E staining)
1. Visual observation The cross section of the cochlea and the bony axis (cochlear axis) between them can be seen. The cochlea of the guinea pig is rolled up into more circles, so there are three to four cochlear tubes on both sides of the cochlear axis in the section.
2. Low magnification observation: The bone of the cochlea is loose, with blood vessels, nerves and spiral ganglia inside. The cochlear axis protrudes into the cochlea and forms a bone spiral plate. At the base of the bone spiral plate, some round cells with large cell bodies, round nuclei and light coloring can be seen, which are the spiral ganglion cells. On the outer side of the bone spiral plate is the cochlea, which is triangular in section.
3. High magnification observation Choose a good cross section of the cochlea for observation. It can be seen that the cochlea is divided into upper, outer and lower walls. The upper wall is the vestibular membrane. The outer wall is the spiral ligament formed by the thickening of the cochlear ossicles, and the surface of the spiral ligament is covered with a complex layer of columnar epithelium with blood vessels, which is called the vascular stripe. The lower wall of the cochlea consists of the basilar membrane and the marginal part of the bony spiral plate. Focus on the basement membrane epithelium specialized for auditory receptors, which consists of two types of cells:
(1) Hair cell Columnar in shape with short auditory hairs on the free surface.
(2) Supporting cells Various morphologies, which can be categorized into finger cells and columnar cells according to their location and morphology.
A gelatinous membrane protruding into the cochlea from the thickened portion of the periosteum at the edge of the bony spiral plate is called the capping membrane.
(ii) Demonstration of the observation of baroreceptors
1. ellipsoid saccule and globular saccule The epithelial cells are high columnar, with hair cells and supporting cells. The hairs of the hair cells are short and are encased in the otolithic membrane.
2. Pituitary cristae The epithelium is mound-shaped and also has hair cells and supporting cells. The hairs of the hair cells are encapsulated in a higher gelatinous jugular cap.
Sixth, the structure of the skin and its appendages
In conjunction with the skin model, observe a vertical section of the human scalp (H I E stain).
(i) Low magnification observation
Observe the stratification of the skin and the appendages.
1. The layers of the skin can be divided into epidermis, dermis and subcutaneous tissue from the surface to the inside.
(1) the epidermis for the keratinization of the complex flat epithelium, is a number of layers of dense nuclei, stained parts of the deeper, the surface and the keratinized layer.
(2) dermis consists of dense connective tissue, fibers are stained red, and the nuclei of various connective tissue cells are stained blue. Dermis and epidermis at the junction of the formation of a number of papillary elevations, this layer is the papillary layer, the papillary layer of the deep for the reticular layer, there is no obvious boundary between the two layers of the reticular layer can be seen in the sweat glands, hair follicles, blood vessels and other cross-sections. In some sections, the deeper part of the reticular layer can still be seen in the cross section of the ring layer of vesicles.
(3) Subcutaneous tissue which contains more fat cells.
(2) Hair by the hair shaft and hair root composition. The hair shaft is exposed outside the skin, and the hair root is buried in the skin. Hair root is surrounded by hair follicles. Hair follicle end expanded into a ball of hair. The bottom of the ball of hair has connective tissue protruding into the formation of hair papillae. In the epidermis and the hair follicle formed an obtuse angle side there are oblique rows of smooth muscle bundles, for the vertical hair muscle. An intact hair is easily seen on section, but various oblique sections of the hair follicle can be seen.
3. Sweat glands are divided into secretory and excretory parts. Secretory part in the deep dermis, is a single layer of cuboidal epithelium composed of fine curved tubes, coiled into a mass. In the section was cut into different sizes, surrounded by a single layer of cuboidal epithelium cross-section structure. The conduit section is a slender epithelial tube, the walls of which are surrounded by two or three layers of low columnar cells that wind from the deep dermis toward the epidermis, and is seen only in intermittent sections on the section. If it can be seen crossing the epidermis between two dermal papillae to open on the surface of the epidermis, the epidermal portion is visible as a single round hole with a cell-free wall.
4. sebaceous gland located between the hair follicle and the vertical hair muscle of the vesicular gland, the secretion of the central part of the cell is large and translucent, light color, the surrounding cells are small and dark color. Some sections of the sebaceous glands can be seen on the surface of the hair follicle or skin with a short duct opening.
(ii) High magnification observation Observe the stratification of the epidermis, which is divided from deep to light:
1. Basal layer is a layer of cubic or short columnar cells adjacent to the dermis, the cells are neatly arranged, the nucleus is ovoid, and the staining is darker.
2. Spiny layer is generally composed of 4-10 layers of cells. The cell body is large and polygonal. The nucleus is large and spherical.
3. The stratum corneum is several layers of red corrugated, non-nuclear flat cells on the surface of the epidermis. Between the stratum spinosum and stratum corneum, there are occasionally 1 to 2 layers of granular layer, the cells are shuttle-shaped, the nucleus is lighter staining, is a tendency to degenerate cells. The nuclei are lighter in staining, and the cells tend to degenerate.
VII. Demonstrate the observation of the following electron microscopic structures
1. surface view of the optic rod and cone of retinal optic cells Observe with scanning electron microscope pictures. The pigment epithelium is stripped away and the optic rod and cone are viewed from the scleral side. Some of the outer segments of the optic rod are easily peeled off together with the pigment epithelium, making the rod more or less short, so that the cones can be clearly seen. Normally, the cones are shorter and fewer in number than the rods.
2. The outer segments of the optic rod cells are observed with transmission electron microscope pictures. The membrane discs of the outer segment of the optic rod cells, the protrusions of the pigment epithelium and the pigment granules can be seen.
3. Surface view of auditory hair cells Observed with a scanning electron microscope picture. Surface view of the cochlear duct spiral apparatus at the base of the cochlea, showing one row of inner hair cells and three rows of outer hair cells. The hairs of the inner and outer hair cells are arranged in a "V" shape.