External leaf characteristics (such as shape, margin, hairs, etc.) are important for identifying plant species, and botanists have developed a rich terminology for describing leaf characteristics. These structures are a part of what makes leaves determinant, they grow and achieve a specific pattern and shape, then stop. Other plant parts like stems or roots are non-determinant, and will continue to grow as l ...

See also:

Leaf, Leaf - Leaf anatomy, Leaf - Epidermis, Leaf - Mesophyll, Leaf - Veins, Leaf - Leaf morphology, Leaf - Basic leaf types, Leaf - Arrangement on the stem, Leaf - Divisions of the lamina blade, Leaf - Venation arrangement of the veins, Leaf - Leaf terminology, Leaf - Margins edge, Leaf - Tip of the leaf, Leaf - Base of the leaf, Leaf - Surface of the leaf, Leaf - Hairiness trichomes, Leaf - Adaptations

Read more here: » Leaf: Encyclopedia II - Leaf - Leaf morphology

See also:

Leaf, Leaf - Leaf anatomy, Leaf - Epidermis, Leaf - Mesophyll, Leaf - Veins, Leaf - Leaf morphology, Leaf - Basic leaf types, Leaf - Arrangement on the stem, Leaf - Divisions of the lamina blade, Leaf - Venation arrangement of the veins, Leaf - Leaf terminology, Leaf - Margins edge, Leaf - Tip of the leaf, Leaf - Base of the leaf, Leaf - Surface of the leaf, Leaf - Hairiness trichomes, Leaf - Adaptations

Read more here: » Leaf: Encyclopedia II - Leaf - Leaf terminology

Definition and meaning of epidermis:

epidermis - the outer epithelial layer of the body

(Source: US National Oceanic and Atmospheric Administration (NOAA) )

Also see these pages: Oceanography, Oceanography Sitemap, Coral Reef, Environment, Sustainability, Climate Change,

In botany, a leaf is an above-ground plant organ specialized for photosynthesis. For this purpose, a leaf is typically flat (laminar) and thin, to expose the chloroplast containing cells (chlorenchyma tissue) to light over a broad area, and to allow light to penetrate fully into the tissues. Leaves are also the sites in most plants where respiration, transpiration, and guttation take place. Leaves can store food and water, and are modified in some plants for other purposes. The comparable structures of ferns are correctl ...

Including:

Leaf - Leaf anatomy
Leaf - Epidermis Leaf - Mesophyll Leaf - Veins
Leaf - Leaf morphology
Leaf - Basic leaf types Leaf - Arrangement on the stem Leaf - Divisions of the lamina blade Leaf - Venation arrangement of the veins
Leaf - Leaf terminology
Leaf - Margins edge Leaf - Tip of the leaf Leaf - Base of the leaf Leaf - Surface of the leaf Leaf - Hairiness trichomes
Leaf - Adaptations

Read more here: » Leaf: Encyclopedia - Leaf

In dermatology, an abrasion is superficial damage to the skin, generally not deeper than the epidermis. It is more superficial than an excoriation, although it can give mild bleeding. Mild abrasions do not scar, but deep abrasions may lead to the development of scarring tissue. See also. Wound ...

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A structurally complete leaf of an angiosperm consists of a petiole (leaf stem), a lamina (leaf blade), and stipules (small processes located to either side of the base of the petiole). The point at which the petiole attaches to the stem is called the leaf axil. Not every species produces leaves with all of these structural parts. In some species, paired stipules are not obvious or are absent altogether; a petiole may be absent; or the blade may not be laminar (flattened). The tremendou ...

See also:

Leaf, Leaf - Leaf anatomy, Leaf - Epidermis, Leaf - Mesophyll, Leaf - Veins, Leaf - Leaf morphology, Leaf - Basic leaf types, Leaf - Arrangement on the stem, Leaf - Divisions of the lamina blade, Leaf - Venation arrangement of the veins, Leaf - Leaf terminology, Leaf - Margins edge, Leaf - Tip of the leaf, Leaf - Base of the leaf, Leaf - Surface of the leaf, Leaf - Hairiness trichomes, Leaf - Adaptations

Read more here: » Leaf: Encyclopedia II - Leaf - Leaf anatomy

Skin is composed of the epidermis and the dermis. Below these layers lies the hypodermis, which is not usually classified as a layer of skin. The outermost epidermis is made up of stratified squamous epithelium with an underlying basement membrane. It contains no blood vessels, and is nourished by diffusion from the dermis. The main type of cells which make up the epidermis are keratinocytes, with melanocytes and Langerhans cells also present. The epidermis can be further subdivided into the following strataSee also:

Skin, Skin - Layers, Skin - Types, Skin - Functions, Skin - Hygiene, Skin - Aging and disease

Read more here: » Skin: Encyclopedia II - Skin - Layers

Baleen (also called whalebone) is a substance made of keratin and is therefore stiff but somewhat elastic. Whalebone is a modification of the epidermis. A bony mineral, hydroxyapatite, is also present in baleen in small amounts, along with traces of manganese, copper, boron, iron, and calcium. Baleen makes up baleen plates, which are arranged in two parallel rows that look like combs of thick hair; they are attached to the upper jaws of baleen whales. Whales use these combs for filter feeding. Whales are the only ...

Including:

Baleen - Evolution of Baleen Baleen - Baleen in Filter Feeding Baleen - Uses of Baleen

Read more here: » Baleen: Encyclopedia - Baleen

Feathers are one of the epidermal growths that form the distinctive outer covering, or plumage, on birds. They are the outstanding characteristic that distinguishes the Class Aves from all other living groups. Other Theropoda also had feathers (see Feathered dinosaurs). Feather - Characteristics. Feathers are among the most complex structural organs found in vertebrates: integumentary appendages, formed by controlled proliferation of cells in the epidermis, or outer skin layer, that produce keratin proteins ...

Including:

Feather - Characteristics Feather - Origins Feather - Feathered dinosaurs Feather - Human uses

Read more here: » Feather: Encyclopedia - Feather

A carpel is the female reproductive organ of a flower; the basic unit of the gynoecium. The parts of the carpel are: the stigma (plural: stigmas), usually the terminal (end) portion that has no epidermis and is fitted to receive pollen (male gametes); it is commonly somewhat glutinous or viscid; the style, a stalk connecting the stigma with the ovary below containing the transmitting tract, which facilitates the movement of the male gamete to the ovule; and< ...

Including:

Carpel - Carpel anatomy
Carpel - The ovule
Carpel - Miscellaneous

Read more here: » Carpel: Encyclopedia - Carpel

Skin is composed of the epidermis and the dermis. Below these layers lies the hypodermis(subcutaneous adipose layer), which is not usually classified as a layer of skin. The outermost epidermis is consists of stratified squamous epithelium with an underlying basement membrane. It contains no blood vessels, and is nourished by diffusion from the dermis. The main type of cells which make up the epidermis are keratinocytes, with melanocytes and Langerhans cells also present. The epidermis can be further subdivided in ...

See also:

Skin, Skin - Layers, Skin - Types, Skin - Functions, Skin - Hygiene, Skin - Aging and disease

Read more here: » Skin: Encyclopedia II - Skin - Layers

Special adaptations of roots are found among epiphytic or semi-epiphytic plants such as Orchid sp. and Clivia. Velamen is a spongy, multiple epidermis that covers the roots of some of these plants. The velamen of an orchid is the white or gray covering of aerial roots (when dry, and usually more green when wet as a result of the appearance of underlying photosynthetic structures). It is many cell layers thick and capable of absorbing atmospheric moisture and nutrients. Often, the roots of orchids are associated with symbiotic bacteria ...

Read more here: » Velamen: Encyclopedia - Velamen

A black head (technically known as a comedo) is a yellowish, reddish (with white cap) or blackish bump or plug on a skin. It is caused by an excess of oils that have accumulated in the sebaceous gland's duct typically caused by excessive oil, make up and dirt. The substance found in these bumps mostly consist of keratin (horny epidermis cells) and modified sebum (oily secretions of the sebaceous gland) [1]. Factors that cause black heads: Lack of water in your system Excess dead cells blocking the opening ...

Including:

Black head - Treatment

Read more here: » Black head: Encyclopedia - Black head

Hair is a filamentous outgrowth of the skin found only in mammals. In some species it is absent at certain stages of life. It projects from the epidermis, though it grows from follicles deep in the dermis. So-called "hairs" (trichomes) are also found on plants. The projections on insects and spiders are actually bristles. The hair of non-human species is commonly referred to as fur. There are varieties of cats, dogs, and mice bred to have little or no visible hair. Hair serves a number of different functions. It provides insula ...

Including:

Hair - Human hair Hair - Structure Hair - Types of hair Hair - Hair change with aging Hair - Androgenic hair Hair - Other information

Read more here: » Hair: Encyclopedia - Hair

The epidermis of an embryo, young, or half-grown Crocodilia contains the rete Malpighii: a single layer of short, cylindrical cells. Over the rete are somewhat flattened, disk-shaped cells formed by transverse division of the underlying rete cells. On the outside lies the epitrichial layer, a mosaic of polygonal cells each with an oval nucleus near its middle. Between the epitrichial cells are small oval holes, not unlike the stomata in the epidermis of plant tissues. Bronn[2] thinks these are not ar ...

See also:

Crocodile exoskeleton, Crocodile exoskeleton - Structure and anatomy, Crocodile exoskeleton - Histology of the integument, Crocodile exoskeleton - Sources

Read more here: » Crocodile exoskeleton: Encyclopedia II - Crocodile exoskeleton - Histology of the integument

Feathers are among the most complex structural organs found in vertebrates: integumentary appendages, formed by controlled proliferation of cells in the epidermis, or outer skin layer, that produce keratin proteins. The β-keratins in feathers, beaks and claws — and the claws, scales and shells of reptiles — are composed of protein strands hydrogen-bonded into β-pleated sheats, which are then further twisted and crosslinked by disulfide bridges into structures even tougher than the α-ke ...

See also:

Feather, Feather - Characteristics, Feather - Origins, Feather - Feathered dinosaurs, Feather - Human uses

Read more here: » Feather: Encyclopedia II - Feather - Characteristics

A subcutaneous injection is administered into the subcutis, the layer of skin directly below the dermis and epidermis, collectively referred to as the cutis. Subcutaneous injections are relatively painless and highly effective in administering such medications as insulin or goserelin. A person with Type I diabetes mellitus typically injects insulin subcutaneously. Places on the body where people can inject insulin most easily are: The outer area of the upper arm. Just above and below the waist, except the ...

See also:

Injection medicine, Injection medicine - Subcutaneous Injection, Injection medicine - Intramuscular Injection, Injection medicine - Intravenous Infusion

Read more here: » Injection medicine: Encyclopedia II - Injection medicine - Subcutaneous Injection

Hydras have two main body layers separated by mesoglea, a gel-like substance. The outer layer is the epidermis and the inner layer is called the gastrodermis. The cells making up these two body layers are relatively simple cells. The nervous system of Hydra is a nerve net, which is simple compared to mammalian nervous systems. They do not have a recognisable brain. Nerve nets connect sensory photoreceptors and touch sensitive nerve cells that are found in the body wall and tentacles of hydras. Respiration occurs by diffusion through the epidermis. Some excretion and ...

See also:

Hydra genus, Hydra genus - Form, Hydra genus - Morphology, Hydra genus - Motion and locomotion, Hydra genus - Reproduction, Hydra genus - Feeding, Hydra genus - Morphallaxis, Hydra genus - Senescence

Read more here: » Hydra genus: Encyclopedia II - Hydra genus - Morphology

Wraith Stargate - Anatomy and physiology. The Wraith are characterized by a pale blue or light-green epidermis, yellow eyes, and white, black, or red hair. The majority of Wraith so far observed are male. Adult female Wraith that have been seen seem to fill only the rôle of "Keeper", overseeing Hive-ships, rather like a queen bee. ("Rising", "The Hive") Wraith exhibit bipedal locomotion and have mostly humanoid characteristics. These characteristics include noticible gender dimorphism; female Wraith have ...

See also:

Wraith Stargate, Wraith Stargate - Overview, Wraith Stargate - Origin, Wraith Stargate - Biology, Wraith Stargate - Anatomy and physiology, Wraith Stargate - Means of nourishment, Wraith Stargate - Communication and telepathy, Wraith Stargate - The force of death, Wraith Stargate - Society, Wraith Stargate - Feeding Cycle, Wraith Stargate - Technology, Wraith Stargate - Wraith tactics, Wraith Stargate - The Atlantis Expedition Team, Wraith Stargate - Individually known Wraith

Read more here: » Wraith Stargate: Encyclopedia II - Wraith Stargate - Biology

Chronic wounds may affect only the epidermis and dermis, or they may affect tissues all the way to the fascia (Crovetti et al., 2004). They may be formed originally by the same things that cause acute ones, such as surgery or accidental trauma (Moreo, 2005), or they may form as the result of systemic infection, vascular, immune, or nerve insufficiency, or comorbidities such as neoplasias or metabolic disorders (Crovetti et al., 2004). The reason a wound becomes chronic is that the body’s ability to deal with the damage is overwhelmed by factors such as repeated trauma, continued pressure, ischemia, ...

See also:

Chronic wound, Chronic wound - Epidemiology, Chronic wound - Types, Chronic wound - Venous ulcers, Chronic wound - Diabetic ulcers, Chronic wound - Pressure ulcers, Chronic wound - Contributing factors, Chronic wound - Pathophysiology, Chronic wound - Ischemia, Chronic wound - Bacterial colonization, Chronic wound - Growth factors and proteolytic enzymes, Chronic wound - Treatment, Chronic wound - Preventing and treating infection, Chronic wound - Treating ischemia and hypoxia, Chronic wound - Growth factors and hormones

Read more here: » Chronic wound: Encyclopedia II - Chronic wound - Pathophysiology