Human-being is a highly evolved, rational living being. Human is a mammal because the young ones are reared by breastfeeding it is a vertebrate because it has a bony vertebral column on its back.
Human body is made up of bones and fleshy. Bones give the human body its shape. The whole body is covered with a membrane known as skin that possesses hairs. The skin protects the body from external injuries and infections.
The human body is divided into three main parts:
1. Head: The topmost (uppermost) part of the body is the head that is placed above the neck. It is more or less round in shape.
The anterior or front part of the head is known as face. Except the face, the head is covered with hairs.
There are two ears on either side of the face. The external part of the ear is known as pinna.
There are two spherical eyes on both the sides of the median nose. Eyes have eyebrows above them. Each eye has an upper and a lower eyelid. The margin of the eyelid is provided with small hairs called eyelash. Eyebrows and eyelids protect the eyes from dust and excessive light.
The frontal portion above the eye is called forehead. In between the two eyes there is a conical, slightly elevated structure called nose, it has two openings known as nostrils. The portion of the face below the eyes and lateral to the nose is known as cheek.
Just below the nose, the mouth is located which is bound by two lips – the upper and the lower.
The almost conical lowermost portion of the face is known as chin. Inside the mouth, a chamber called buccal cavity is present. In the buccal cavity, two rows of teeth and a fleshy tongue are present.
2. Neck: The short, cylindrical portion connecting the head with the trunk is known as neck. The front portion of the neck is called the throat and the back portion is the nape of the neck.
3. Trunk: The main portion of human body other than the limbs is called the trunk. The trunk can be broadly divided into thorax, abdomen and pelvis.
The thorax is the uppermost broad flat portion of the trunk. The front part of the trunk remaining below the throat is called the chest. On the chest, there are two mammary glands. The dorsal surface of the thorax is the back of the thorax. The upper two sides of the thorax extending laterally from the neck towards the arms are called shoulders.
The chest gradually goes down and forms a narrow waist. The lower portion of the trunk lying below the chest is called abdomen. There is a circular groove in the centre of the abdomen that is called navel.
The lowermost part of the trunk is called pelvis. The lowermost, dorsolateral elevated portion of the pelvis is known as buttock. The genital organs are located in the ventral portion of the pelvis and lying between two legs.
There are two forelimbs or arms and two hind limbs or legs.
The forelimbs start laterally from the shoulders. Each forelimb has three parts – upper arm, forearm and hard. The joint of the upper arm and forearm is known as elbow, the junction between the hand (palm) and forearm is called wrist. The hand includes the flat expanded palm, the wrist and five digits or fingers. Each digit or finger has nail at the top. The fingers from the thickest to the thinnest are named as thumb, index finger, middle finger, ring finger, and little finger.
Man has two hind limbs or legs remaining attached to the ventral and lateral sides of the pelvis. The upper muscular portion of the leg is the thigh. The middle tubular part of the leg is shin, the lower flat part is foot.The joint between the thing, and shin is called knee. Each foot has five digits or toes with nails at the tip. The lower portion of the foot is the sole and the back portion of the foot is the heel. The joint between the foot and the skin is the ankle.