Functions of Bones Bones form an important component of the Skeleton System . They perform a wide range of important functions that can be classified into three categories: Mechanical Functions of bones Protection:At numerous places inside the body, bones serve to protect important and delicate organs. The...

Deep Fascia Deep fascia is the dense fibrous connective tissue that interpenetrates and surrounds the muscles, bones, nerves and blood vessels of the body. It is in the form of a fibrous sheet which invests the body beneath the superficial fascia. It is devoid of fat, and is usually inelastic and tough. Distribution...

Superficial Fascia Superficial fascia is a general coating of the body beneath the skin, made up of loose areolar tissue with varying amounts of fat. It is the layer that primarily determines the shape of the body. In addition to its subcutaneous presence, the supreficial fascia surrounds organs , glands and neurovascular...

Sweat Glands Sweat glands, also known as sudoriferous glands, are small tubular structures of skin that produce sweat. They are distributed all over the skin, except lips, glans penis and nail bed. These glands are of two types: Eccrine and Apocrine. Eccrine Sweat Glands Eccrine glands are much more abundant...

Sebaceous Glands Sebaceous glands are microscopic glands in the skin that secrete an oily secretion known as sebum. They are widely distributed all over the dermis of skin, except for the palms and soles. They are especially abundant in the scalp and face. They are also very numerous around the apertures of ear, nose,...

Anatomy of Hair Hair are keratinous filaments derived from invaginations of the germinative layer of epidermis into the dermis. These are peculiar to mammals (like feathers to the birds), and help in conservation of their body heat. However, in man the heat loss is prevented b the cutaneous sensation of touch Distribution...

Anatomy of Nail Nail is a hardened keratin plates (cornified zone) on the dorsal surface of the tips of fingers and toes, acting as a rigid support for the digital pads of terminal phalanges. They are horn-like envelopes covering the dorsal aspect of terminal phalanges of fingers and toes of human body. Parts...

Lines and Ridges of Skin The skin is marked by three types of surface irregularities: The tension lines, flexure lines and papillary ridges. Tension lines Form a network of linear furrows which divided the surface into polygonal or lozenge shaped areas . These lines to some extent correspond to variations in...

Structure of Skin The skin is composed of two distinct layers: epidermis and dermis. Epidermis It is the superficial avascular layer of stratified squamous epithelium, It is ectodermal in origin and gives rise to the appendages of the skin, namely hair, nails, sweat glands and sebaceous glands. Structurally...

Pigmentation of Skin The color of the skin is determined by at least five pigments present at different levels and places of the skin. These pigments are: Melanin: It is brown is color and is found in the germinative zone of the epidermis. Melanoid: It resembles the melanin pigment in structure, however...

Skin Skin is the general covering of the entire external surface of the body, including the external auditory meatus and the outer surface of tympanic membrane. The skin is continuous with the mucous membrane at the orifices of the body.  The skin performs a large number of important functions, and consequently...

Comparison of Sympathetic and Parasympathetic Nervous Systems Sympathetic and parasympathetic nervous systems are two divisions of the autonomic nervous system of body. They are closely coordinated with one another to regulate the functions of human body. In the lines below a brief comparison of the two systems is...

Autonomic Nervous System Autonomic nervous system is the part of the Peripheral Nervous System (PNS), which control the unconscious functions of body. Autonomic nervous system controls involuntary activities of the body, like sweating, salivation, peristalsis, etc. It differs fundamentally from the somatic nervous...

Parasympathetic Nervous System Parasympathetic nervous system is one of the two main divisions of the autonomic nervous system.  It is responsible specifically for stimulation of activities that occur when the body is at rest. The main goal of this system is to conserve the resources of the body so that they...

Sypmathetic Nervous System Sympathetic nervous system is a part of the autonomic nervous system of body. It is mainly concerned with mobilization of body’s resources under stress to induce the “fight or flight response“. Sympathetic nervous system is also known as thoracolumbar outflow because it arises from T1...

Nerve Fibers Nerve fiber is a thread like extension of a neuron, which is formed by the axon and its covering. Thus each nerve fiber is an axon with its coverings. Larger axons are covered by a myelin sheath and are termed myelinated or medullated fibers. The fatty nature of myelin is responsible for the glistening...