Introduction
The Human Body, composed of several different types of cells is the structure of a human being. The cells together create tissues and organ systems. The human body on the outer surface primarily consists of a head, neck, trunk (thorax & abdomen), arms, hands, legs and feet.
The main organ systems in the human body are as follows:
- Circulatory System - Heart, Lungs, Brain, Kidneys
- Respiratory System - Nose, Lungs, Pharynx, Bronchi
- Digestive System - Mouth, Tongue, Teeth, Pharynx, Diaphragm, Stomach, Spleen, Liver, Gallbladder, Pancreas, Small Intestine
- Muscular System - Skeletal Muscle, Cardiac Muscle, Smooth Muscle
- Nervous System - Brain, Spinal Cord, Meninges, Dura Matter
- Reproductive System [ Female] - Cervix, Ovary, Uterus
- Reproductive System [Male] - Testis, Epididymis, Gonads
- Skeletal System - Bones, Cartilage, Tendons, Ligaments
- The adult body is made up of: 100 trillion cells, 206 bones, 600 muscles, and 22 internal organs
- Every square inch of the human body has about 19 million skin cells.
- Every hour about 1 billion cells in the human body must be replaced.
- Human Brain has over 100 billion nerve cells.
- The adult human brain is about 2% of total body weight.
- The only part of the body that has no blood supply is the cornea of the eye. It receives oxygen directly from the air.
- The human brain has a memory capacity which is the equivalent of more than four terabytes on a hard drive.
- A newborn child can breathe and swallow at the same time for up to seven months.
- Human skull is made up of 29 different bones.
- The human heart pumps 182 million litres of blood during the average lifetime.
Human Body
Human Body Facts
| Largest and strongest Bone in the body | Femur (thigh bone) |
| Smallest Bone in the body | Stapes in ear |
| Number of Cells in the body | 75 trillion |
| Volume of Blood in the body | 6 litres (in 70 kg body) |
| Number of Red Blood Cells(R.B.C.) | 1. In male: 5 to 6 million/cubic mm 2. In female: 4 to 5 million/cubic mm |
| Life span of Red Blood Cells(R.B.C.) | 100 to 120 days |
| Life span of White Blood Cell(W.B.C.) | 3-4 days |
| Normal White Blood Cell(W.B.C.) count | 5000-10000/cubic mm |
| Life span of Red Blood Cells(R.B.C.) | 100 to 120 days |
| Life span of White Blood Cell(W.B.C.) | 3-4 days |
| Normal White Blood Cell(W.B.C.) count | 5000-10000/cubic mm |
| Time taken by R.B.C. to complete one cycle of circulation | 20 seconds |
| Other name of Red Blood Cell (R.B.C.) | Erythrocytes |
| Largest White Blood Cells | Monocytes |
| Smallest White Blood Cells | Lymphocytes |
| Who discovered Blood Group | Karl Landsteiner |
| Blood Platelets count | 150,000 - 400,000 platelets per micro litre |
| Haemoglobin (Hb) | 1. In male: 14-15 gm/100 c.c. of blood 2. In female: 11-14 gm/100 c.c. of blood |
| Hb content in body | 500-700 gm |
| pH of Urine | 6.5-8 |
| pH of Blood | 7.36-7.41 |
| Volume of Semen | 2-5 ml/ejaculation |
| Normal Sperm Count | 250-400 million/ejaculation |
| Menstrual cycle | 28 days |
| Menopause age | 45-50 years |
| Blood clotting time | 3-5 minutes |
| Weight of Brain | 1300-1400 gm in human adult |
| Normal Blood Pressure (B.P.) | 120/80 mm Hg |
| Universal blood donor | O |
| Universal blood recipient | AB |
| Average body weight | 70 kg |
| Normal body temperature | 37 degree celsius |
| Breathing Rate at rest | 12-16/minute |
| Number of Spinal Nerves | 31 pairs |
| Largest Endocrine Gland | Thyroid gland |
| Gestation period | 40 weeks or 9 calendar months |
| Normal Heart Beat at rest | 72 beats per minute |
| Largest Gland | Liver |
| Largest Muscle in the body | Gluteus Maximus or Buttock Muscle |
| Smallest Muscle in the body | Stapedius |
| Largest Artery | Aorta |
| Largest Vein | Inferior Vena Cava |
| Largest and longest Nerve | Sciatic Nerve |
| Longest Cell | Neurons (nerve cells) |
| Minimum distance for proper vision | 25 cm |
| Pulse rate | 72 per minute |
| Thinnest Skin | Eyelids |
| Weight of Heart | 200-300 gm |