Cartilage is a flexible connective tissue found in joints between bones, the rib cage, ear, nose, and other areas. It is composed of specialized cells called chondroblasts that produce collagen fibers and ground substance rich in proteoglycans. Cartilage comes in three types - elastic, hyaline, and fibrocartilage - which differ in their amounts of collagen, ground substance and elastin. Skeletal muscle is striated, voluntary muscle tissue found throughout the body that is attached to bones via tendons and composed of long, cylindrical myofibers formed from fused myoblasts. Smooth muscle is involuntary muscle responsible for contracting hollow organs like blood vessels, and differs from skeletal muscle in its structure and slower contraction

1. In genetics, an insertion (also called an insertion mutation) is the addition of one or
more nucleotide base pairs into a DNA sequence. This can often happen in microsatellite regions due to
the DNA polymerase slipping. Insertions can be anywhere in size from one base pair incorrectly inserted
into a DNA sequence to a section of one chromosome inserted into another.
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A joint is the location at which two or more bones make contact. They are constructed to allow
movement (except for skull bones) and provide mechanical support, and are classified structurally and
functionally
Cartilage /ˈkɑrtɨlɨdʒ/ is a flexible connective tissue found in many areas in the bodies of humans and
other animals, including the joints between bones, the rib cage, the ear, the nose, the bronchial tubes and
the intervertebral discs. It is not as hard and rigid asbone but is stiffer and less flexible than muscle.
Cartilage is composed of specialized cells called chondroblasts that produce a large amount
of extracellular matrix composed of collagen fibers, abundant ground substancerich in proteoglycan,
and elastin fibers. Cartilage is classified in three types, elastic cartilage, hyaline
cartilage and fibrocartilage, which differ in the relative amounts of these three main
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components. Chondroblasts that get caught in the matrix are calledchondrocytes. They lie in spaces
called lacunae with up to eight chondrocytes per lacuna.
Skeletal muscle is a form of striated muscle tissue existing throughout the human body, and which is
under control of the somatic nervous system; that is to say, it is voluntarily controlled. It is one of three
major muscle types, the others being cardiac andsmooth muscle. As their name suggests, most skeletal
muscles are attached to bones by bundles of collagen fibers known as tendons.
Skeletal muscle is made up of individual components known as myocytes, or "muscle cells", sometimes
colloquially called "muscle fibers". They are formed from the fusion of developmental myoblasts (a type of
embryonic progenitor cell that gives rise to a muscle cell). These long, cylindrical, multinucleated cells are
also called myofibers.
Smooth muscle is responsible for the contractility of hollow organs, such as blood vessels, the
gastrointestinal tract, the bladder, or the uterus. Its structure differs greatly from that of skeletal muscle,
although it can develop isometric force per cross-sectional area that is equal to that of skeletal muscle.
However, the speed of smooth muscle contraction is only a small fraction of that of skeletal muscle.
Cardiac muscle (heart muscle) is a type of involuntary striated muscle found in the walls and histological
foundation of the heart, specifically the myocardium. Cardiac muscle is one of three major types of
muscle, the others being skeletal and smooth muscle. The cells that comprise cardiac muscle,
called cardiomyocytes ormyocardiocytes, can contain one, two, or (very rarely) three or
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four nuclei. Coordinated contractions of cardiac muscle cells in the heart propel blood out of
theatria and ventricles to the blood vessels of the left/body/systemic and right/lungs/pulmonary circulatory
systems. This complex of actions makes up thesystole of the heart.
Cardiac muscle cells, like all tissues in the body, rely on an ample blood supply to deliver oxygen and
nutrients and to remove waste products such as carbon dioxide. Thecoronary arteries fulfill this function.
voluntary muscle
noun, Anatomy .
muscle whose action is normally controlled by an individual's will;mainly skeletal
muscle, composed of parallel bundles of striated,multinucleate fibers.

2. Involuntary muscles are muscles that are not controllable consciously, and instead contract due to
unconscious impulses sent by the autonomic nervous system or certain specialized cells or hormones.
Both smooth muscle and cardiac muscle can be classified as involuntary muscles. Smooth muscle is
comprised of spindle-shaped cells that have no striations and is found in numerous locations throughout
the human body. Cardiac muscle is striated rather than smooth, and is found only within the walls of the
heart.
Smooth muscles are involuntary muscles composed of thick and thin protein filaments that are
homologous to the organelles known as myofibrils found in skeletal muscles. The thin filaments are
composed of a globular protein called actin, while the thick ones are made up of a motor protein called
myosin. Smooth muscles require extracellular calcium ions to contract: the ions activate a nucleotide
called Adenosine triphosphate (ATP), which then activates the myosin filaments. The myosin filaments
attach to the actin filaments in a process known as the crossbridge cycle, which causes the thick and thin
filaments to slide over each other and contract. When the myosin filaments release the actin filaments,
the muscle relaxes.
The triceps brachii muscle (Latin for "three-headed arm muscle") is the large muscleon the back of
the upper limb of many vertebrates. It is the muscle principally responsible for extension of the elbow
joint (straightening of the arm).
In human anatomy, the biceps brachii, or simply biceps in common parlance, is, as the name implies, a
two-headed muscle. The biceps lies on the upper arm between the shoulder and the elbow. Both heads
arise on the scapula and join to form a single muscle belly which is attached to the upper forearm. While
the biceps crosses both theshoulder and elbow joints, its main function is at the latter where it flexes the
elbow andsupinates the forearm. Both these movements are used when opening a bottle with a
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corkscrew: first biceps unscrews the cork (supination), then it pulls the cork out (flexion).
Common ailments of the skin
1. Acne
Acne is a skin disorder that causes pimples when the passageway that connects the skin’s pores to the
oil glands becomes clogged.
Acne, which appears most often on the face, neck, shoulders, chest and back, can come in many forms.
Whiteheads and blackheads are the most commonly known; nodular and cystic acne are more severe
because they form deep in the skin and can cause scars
2. Eczema
Eczema is a "grab-bag term," which Alexiades-Armenakas said comes from the Greek word for "boils
over."
3. Seborrheic Dermatitis
Seborrheic dermatitis, which causes oily, waxy patches to develop on the scalp, is distinct from other
forms of dermatitis
5. Psoriasis
Psoriasis is a chronic and disfiguring genetic disease. It is a buildup of excess skin tissue that looks red
and thick and is covered with silvery scales. It first appears on the elbows and knees, but can spread to
other parts of the limbs and even the trunk. Certain forms affect particular areas like the hands, scalp or
the joints.
Atopic Dermatitis
Atopic dermatitis, more commonly known as eczema, is a chronic skin condition characterized by dryness
and intense itching. Repetitive scratching of the skin typically causes swelling and redness. Eventually,
the skin can break open and ooze fluid. As the skin heals, scaly crusts form. The onset of atopic
dermatitis most commonly occurs in infancy and early childhood.