Integument

Every organism has a layer or covering that separates it from the environment and also protects it from every matter that is foreign to its body. This covering also establishes a communication with the environment around the organism that makes it possible for the organism to live and sustain in the particular environment.

The integument meaning is stated as a matter or layer that covers or can be said that encloses the parts of the organism. This can be a cuticle, membrane, or skin that envelops a layer on the organism or a specific part. For instance, in unicellular organisms like protozoans or bacteria, the integument is any secretion produced by an organism to coat itself, or the cell membrane. Among the invertebrate animals, surface or epithelial cells normally form an integument and also have an extra secreted coating while in vertebrates the various derived elements such as hair, feathers, and scales make up the integument meaning.

Integument Definition

The word integument is derived from the Latin word ‘integumentum’ that means a covering. The adjective form of the integument is integumentary. Integument definition as per anatomy (integument medical definition) and botany are mentioned below:

1. If we define integument anatomically, it is the outer covering of an organism that includes seed coat, rind, shell, fur, cuticle, etc that also protects the organs and the body parts. It also acts as the skin or the layer of the body of an organism that constitutes appendages and glands such as claws, hooves, horns, scales, feathers, nails, hair, etc

Anatomy states that the largest organ of the body of the vertebrates and humans is the integument. The important functions that a common integument performs are thermoregulation, insulation, vitamin D synthesis, secretion, sensation, protection against pathogens, abrasive injuries, chemical and thermal.

2. As per botany, the integument definition states the cell layers of the ovule that is outside and encloses the nucellus

According to botany the outer layer of the ovule is an integument. This ovule matures after fertilization and develops as a seed coat. There is one integument layer in the Gymnosperms while angiosperms have two integument layers.

Importance of Integument

Integument acts as an interface between the organism and the environment that it belongs to. The integument performs vital functions such as:

• It protects as well as supports soft tissues of the organism against microbes, other organisms, etc.

• Transduction and reception of external and outer stimuli that includes tactile, chemical, heat, etc.

• Transporting material to different parts of the body for rehydration, dehydration, resorption, secretion, and excretion.

• Regulating heat in the body.

• Respiration.

• Storage of nutrients that includes storing vitamins, synthesis of Vitamin D.

• Locomotion.

• Display or cryptic colouration.

Every organism performs these vital functions in various ways. These functions make them derive different structures.

Integument of the Vertebrate Classes

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Every organism lives and sustains in different habitats and so forms different as well as common integument. Amphioxus constitutes an epidermis that forms a single layer of the cell. The multilayered or stratified epidermis is found in the synapomorphy of Craniata. The tissues that constitute the skin are enamel, dentine, and bone.

Integument of Amphibians

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The transition of the organisms from an aquatic environment to a terrestrial environment is represented by Amphibians. Therefore the integument of amphibians is similar to aquatic organisms such as fish. However, the scales are absent from it. Osteoderms are the small dermal scales that were found in living amphibians and acted as armour.

The water loss in the amphibians is prevented through mucus that functions in the same way as what a fish does to prevent intake of additional water. The only difference being fish performs this function with unicellular glands while amphibians do it through multicellular glands.

Vulnerability is associated with the integument of amphibians and hence they secrete toxins. However, this helps them protect themselves from getting eaten up by other organisms.

Integument of Mammals

The integument of mammals is the basic reason to conform to the structure of the organism. The epidermal layers are normally thick in places that need protection such as palms and soles of the feet.

Hair

Hair forms a protective layer on mammals from heat and foreign matter. Hair grows from follicles but has its roots in the dermis. When the mitosis in the roots stops, the hair growth also stops which results in baldness. These are normally the characteristics of the human integument.

Glands of the Skin

Glands of the skin are responsible for protection, heat regulation, and giving off a scent. The eccrine and apocrine are the sweat glands responsible for heat regulation. The mammary glands are the secretory glands often found in females.

Antlers, Horns, Hoofs, Claws, Nails

All these are integumental derivatives that grow at specific organisms on the specific parts of the body.