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This means the brain-to-body mass ratio is, on average, approximately the same for both sexes. [85] [86] Comparing a male and a female of the same body size, an average difference of 100 grams in brain-mass is present, the male having the bigger and heavier brain. This difference of 100 grams applies over the whole range of human sizes.
Structurally, adult male brains are on average 11–12% heavier and 10% bigger than female brains. [21] Though statistically there are sex differences in white matter and gray matter percentage, this ratio is directly related to brain size, and some [ 22 ] argue these sex differences in gray and white matter percentage are caused by the average ...
An elephant's brain weighs just over 5 kg (11 lb), a bottlenose dolphin's 1.5 to 1.7 kg (3.3 to 3.7 lb), whereas a human brain is around 1.3 to 1.5 kg (2.9 to 3.3 lb). Brain size tends to vary according to body size. The relationship is not proportional, though: the brain-to-body mass ratio varies. The largest ratio found is in the shrew. [57]
Planning began in 1986; [2] the data set of the male was completed in November 1994 and the one of the female in November 1995. The project can be viewed today at the NLM in Bethesda, Maryland. [ 3 ] There are currently efforts to repeat this project with higher resolution images but only with parts of the body instead of a cadaver.
A scanner used to measure bone density using dual energy X-ray absorptiometry. Bone density, or bone mineral density, is the amount of bone mineral in bone tissue.The concept is of mass of mineral per volume of bone (relating to density in the physics sense), although clinically it is measured by proxy according to optical density per square centimetre of bone surface upon imaging. [1]
The embryo and subsequent early fetus appear to be sexually indifferent, looking neither like a male or a female. Over the next several weeks, hormones are produced that cause undifferentiated tissue to transform into either male or female reproductive organs. This process is called sexual differentiation.
Body image is a complex construct, [1] often used in the clinical context of describing a patient's cognitive perception of their own body. The medical concept began with the work of the Austrian neuropsychiatrist and psychoanalyst Paul Schilder , described in his book The Image and Appearance of the Human Body first published in 1935. [ 2 ]
Body image – Aesthetic perception of one's own body; Body proportions – Proportions of the human body in art; Body mass index – Relative weight based on mass and height (BMI) Body roundness index – Body scale based on waist circumference and height (BRI) Bust/waist/hip measurements – Measures used for fitting clothing ("Vital statistics")