What makes up the thorax? thorax function.
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The fibrous tunic is composed of the sclera and the cornea. The sclera covers nearly the entire surface of the eyeball. With its external surface being white-coloured, it is commonly known as the “white of the eye”.
Arteries, arterioles, venules, and veins are composed of three tunics known as the tunica intima, tunica media, and tunica externa.
With the exception of capillaries and sinusoids, all larger vessels have the same three basic structural elements (tunics). These are the tunica intima (inner or luminal layer), tunica media (middle layer), and tunica adventitia (outer layer).
In modern biology in general, tunica occurs as a technical or anatomical term mainly in botany and zoology. It usually refers to membranous structures that line or cover particular organs. … An organ or organism that has a tunic(a) may be said to be tunicate, as in a tunicate bulb.
FIG. 869– Horizontal section of the eyeball. From without inward the three tunics are: (1) A fibrous tunic, (Fig. 869) consisting of the sclera behind and the cornea in front; (2) a vascular pigmented tunic, comprising, from behind forward, the choroid, ciliary body, and iris; and (3) a nervous tunic, the retina.
| Fibrous tunic of eyeball | |
|---|---|
| TA2 | 6743 |
| FMA | 58102 |
| Anatomical terminology | |
Tunica fibrosa refers to the outer fibrous layer of the eye. This includes the sclera and the cornea, which are continuous with one another.
Structure and Function The fovea centralis is located in the center of the macula lutea, a small, flat spot located exactly in the center of the posterior portion of the retina. As the fovea is responsible for high-acuity vision it is densely saturated with cone photoreceptors.
The tunica intima differs from the inner layer of an artery: many veins, particularly in the arms and legs, have valves to prevent…
- Prescription medicines or non-prescription medicines like decongestants. These have ingredients that cause blood vessels to narrow to provide relief.
- Some medical conditions. …
- Some psychological problems, such as stress. …
- Smoking. …
- Being outside in the cold.
Myointimal cells are situated between the internal elastic lamina and endothelial cells. They often have myofilaments and other characteristics of smooth muscle; but they are not normally in contact with circulating blood (Fig.
- blouse.
- coat.
- jacket.
- robe.
- chiton.
- kirtle.
- surcoat.
- toga.
A tunicate is a marine invertebrate animal, a member of the subphylum Tunicata /tjuːnɪˈkeɪtə/. It is part of the Chordata, a phylum which includes all animals with dorsal nerve cords and notochords (including vertebrates).
Although tunicates are invertebrates (animals without backbones) found in the subphylum Tunicata (sometimes called Urochordata), they are part of the Phylum Chordata, which also includes animals with backbones, like us.
| Tunic | |
|---|---|
| Developer(s) | Andrew Shouldice |
| Publisher(s) | Finji |
| Engine | Unity |
| Platform(s) | Mac OS X Microsoft Windows Xbox Series X/S Xbox One |
The conjunctiva helps lubricate the eye by producing mucus and tears, although a smaller volume of tears than the lacrimal gland. It also contributes to immune surveillance and helps to prevent the entrance of microbes into the eye.
They appeared in the middle of the 14th century and were worn under outer garments.
The innermost layer of the eye is the neural tunic, or retina, which contains the nervous tissue responsible for photoreception. The eye is also divided into two cavities: the anterior cavity and the posterior cavity. The anterior cavity is the space between the cornea and lens, including the iris and ciliary body.
Neural components: Include the retina and the optic nerve: Retina – cup-shaped outgrowth of the brain which forms the inner layer of the eyeball. Optic nerve – CNII responsible for vision.
The retina consists of two layers: the sensory retina, which contains nerve cells that process visual information and send it to the brain; and the retinal pigment epithelium (RPE), which lies between the sensory retina and the wall of the eye.
The outermost layer of the eye is called the fibrous tunic. The sclera and cornea make up the fibrous tunic.
Sclera. The sclera (SKLAIR-uh) is the white part of the eyeball, which makes up the posterior five- sixths of the fibrous tunic.
Aqueous humor – the clear, watery fluid between the cornea and the front of the vitreous. The aqueous humor bathes and nourishes the lens and maintains pressure within the eye. Since the lens and cornea have no blood supply, the aqueous humor performs the blood’s job of carrying nutrients to those structures.
pl. fo·ve·ae (-vē-ē′) 1. A small cuplike depression or pit in a bone or organ.
The natural blind spot (scotoma) is due to lack of receptors (rods or cones) where the optic nerve and blood vessels leave the eye. There can also be artificial blind spots when something blocks light from reaching the photoreceptors, or when there is local adaptation of the retina as just after seeing a bright light.
Unlike arteries, veins contain valves that ensure blood flows in only one direction. (Arteries don’t require valves because pressure from the heart is so strong that blood is only able to flow in one direction.)
The innermost layer of the vein is the tunica intima. This layer consists of flat epithelial cells. These cells allow fluid to flow smoothly and are interspersed with valves that ensure the flow continues in one direction. This continuous layer of epithelial cells holds cells and fluid within the vessel lumen.
The wall of an artery consists of three layers. The innermost layer, the tunica intima (also called tunica interna), is simple squamous epithelium surrounded by a connective tissue basement membrane with elastic fibers. The middle layer, the tunica media, is primarily smooth muscle and is usually the thickest layer.
Vasodilation occurs naturally in your body in response to triggers such as low oxygen levels, a decrease in available nutrients, and increases in temperature. It causes the widening of your blood vessels, which in turn increases blood flow and lowers blood pressure.
Vasoconstriction is the narrowing (constriction) of blood vessels by small muscles in their walls. When blood vessels constrict, blood flow is slowed or blocked. Vasoconstriction may be slight or severe. It may result from disease, drugs, or psychological conditions.
Too coldToo hotHeat loss from skinDecreasesIncreases
Atheromas are raised lesions that protrude into the vessel lumen and contain a soft, yellow, grumous (thick and lumpy) core consisting mainly of cholesterol and cholesterol esters, covered by a white, fibrous cap.
Abstract. Myointimal hyperplasia (MIH) is an arterial wall smooth muscle cell (SMC) proliferative disorder. This process is responsible for a significant number of early and long-term arterial reconstructive and graft failures.
A subendothelial layer, consisting of delicate connective tissue with branched cells lying in the interspaces of the tissue; in arteries of less than 2 mm in diameter the subendothelial layer consists of a single stratum of stellate cells, and the connective tissue is only largely developed in vessels of a considerable …
is that shirt is an article of clothing that is worn on the upper part of the body, and often has sleeves, either long or short, that cover the arms while tunic is a garment worn over the torso, with or without sleeves, and of various lengths reaching from the hips to the ankles.
A tunic is a loose-fitting shirt that looks sort of like a long shirt or a short dress. For a fashionable summer look, you might pair trousers with a comfortable tunic that extends past your waist. The ancient Greeks and Romans were early fans of the tunic, and the loose-fitting garment remains popular in modern times.
part of speech:noundefinition 2:a short coat with a stiff high collar, worn as part of a uniform by soldiers or the like.related words:mantle