Estimating the number of cells in the human body clearly isn’t an easy or straightforward task....
QUIZ WHIZ
Estimating the number of cells in the human body clearly isn’t an easy or straightforward task, but researchers have estimated that the total number of cells that compose the average human adult is around 30 to 40 trillion, with one study putting the number at 37.2 trillion. The majority of these are red blood cells, which make up over 80 percent of the body in number.
206 bones make up the adult human skeleton, providing support and protecting delicate internal organs. Around 640 muscles facilitate the movement of this skeletal structure by contracting upon receiving a signal from the nervous system.
The femur - or thighbone - is the longest and strongest bone in the human body. It runs from around the hip to the knee, and is 48 centimetres long in an average adult male.
The shortest bone in the human body is the stapes, a stirrup-shaped bone in the middle ear, which is only about 3 millimetres long.
The volume of blood, of course, varies by the individual’s size and health, but there are around 4.7 to 5.5 litres of blood in an average human, around 55 percent of which is plasma while the rest is the cellular portion.
Blood carries oxygen to all the tissues in the body and takes away carbon dioxide. It also carries food materials and waste chemicals, and helps fight diseases.
The blood is pumped around the body by the heart in less than a minute. In an average lifespan, the human heart beats more than three billion times!
The muscle that can exert the most pressure is the masseter muscle, which opens and closes the mouth when you chew and can regularly apply as much as 200 pounds of force on the molars when biting and chewing.
The gluteus maximus is the largest muscle in the human body.
The tongue isn’t a single muscle but actually eight different muscles.
The largest organ of the human body is the skin. The largest internal organ is the liver.
Fingernails typically grow at an average rate of about 3.47 mm per month, which roughly comes down to 1 mm per week. Toenails grow much slower than fingernails, at an average rate of around 1.62 mm per month.
The average person breathes around 500 ml of air in one normal breath, inhaling and exhaling 7 or 8 litres of air per minute, or ~11,000 litres of air per day.
In humans, the small intestine is about 6 to 7 meters (20 to 23 feet) long, while the large intestine is about 1.5 meters (5 feet) long. The intestines facilitate digestion and the absorption of water and nutrients.
The liver is the only organ that can regenerate itself, which is why a living person can donate a part of their liver to another recipient; the portion that remains will regenerate itself into a whole liver again.
The cerebrum primarily performs functions related to touch, vision, hearing, speech, reasoning, learning, and emotions.
The cerebellum coordinates muscle movements.
The brainstem connects the cerebrum and cerebellum to the spinal cord and performs several autonomic functions.
The hypothalamus links the nervous system to the endocrine system.
Almost 99% of the mass of the human body is made up of six elements: oxygen, carbon, hydrogen, nitrogen, calcium, and phosphorus. Out of these elements, oxygen is the most abundant, making up about 65% of the body, followed by carbon (18.5), hydrogen (9.5), and nitrogen (3.2).
The adult human body is about 53% water, and because of this water content, it contains more oxygen by mass than any other element (but more hydrogen by atom-fraction - 62% - than any element).
- S.A.
