Copyright © 2006, Elsevier Inc. All rights reserved C HAPTER 6 Puberty

Copyright © 2006, Elsevier Inc. All rights reserved F IGURE 6-1 D IFFERENT DEGREES OF SEXUAL MATURATION AT THE SAME AGE. T HE MALES ARE ALL YEARS OLD, AND THE FEMALES ARE ALL YEARS OLD. T HIS ILLUSTRATES THAT THE DEGREE OF SEXUAL MATURITY CAN VARY WIDELY IN RELATION TO AGE.

Copyright © 2006, Elsevier Inc. All rights reserved F IGURE 6-2 C HANGES IN THE WEIGHT OF AN OVARY AND THE UTERUS WITH AGE.

Copyright © 2006, Elsevier Inc. All rights reserved F IGURE 6-3 C HANGES IN THE WEIGHT OF A SINGLE TESTIS, SEMINAL VESICLE, AND PROSTATE GLAND WITH AGE.

Copyright © 2006, Elsevier Inc. All rights reserved F IGURE 6-4 S TAGES OF PUBIC HAIR DEVELOPMENT IN FEMALES. T HE INFANTILE PATTERN ( STAGE 1) IS NOT SHOWN. R EFER TO THE DESCRIPTION OF THESE STAGES IN T ABLE 6-3.

Copyright © 2006, Elsevier Inc. All rights reserved F IGURE 6-5 S TAGES OF FEMALE BREAST DEVELOPMENT. R EFER TO THE DESCRIPTION OF THESE STAGES IN T ABLE 6-3.

Copyright © 2006, Elsevier Inc. All rights reserved F IGURE 6-6 S TAGES OF MALE GENITAL DEVELOPMENT DURING PUBERTY. R EFER TO THE DESCRIPTION OF THESE STAGES IN T ABLE 6-3.

Copyright © 2006, Elsevier Inc. All rights reserved F IGURE 6-7 C HANGES IN BLOOD LEVELS OF FSH, LH, AND ESTRADIOL IN FEMALES OF DIFFERENT AGES. B LOOD ANDROGEN LEVELS ARE NOT DEPICTED, BUT THESE ALSO RISE AS PUBERTY NEARS. N OTE THAT THE VALUES FOR HORMONE LEVELS ARE IN NANOGRAMS PERCENT ( NG %) OR MICROGRAMS PERCENT ( G %). A NANOGRAM IS OF A MICROGRAM, AND 1 NG % IS 1/1000 EQUIVALENT TO 1.0 NG IN 100 ML OF BLOOD PLASMA. T HUS NOT MANY HORMONE MOLECULES ARE NEEDED TO CHANGE BIOLOGICAL FUNCTION.

Copyright © 2006, Elsevier Inc. All rights reserved F IGURE 6-8 C HANGES IN BLOOD LEVELS OF FSH, LH, AND TESTOSTERONE IN MALES OF DIFFERENT AGES. B LOOD ESTROGEN LEVELS ARE NOT DEPICTED, BUT THESE ALSO RISE SLIGHTLY AS PUBERTY NEARS. F OR AN EXPLANATION OF NG % AND G %, SEE THE LEGEND TO F IG. 6-7.

Copyright © 2006, Elsevier Inc. All rights reserved F IGURE 6-9 D AILY PATTERNS OF LH LEVELS IN BLOOD OF FEMALES AT VARIOUS STAGES OF SEXUAL MATURATION. N OTE THAT DURING PUBERTY, LH LEVELS RISE DURING SLEEP AND EXHIBIT MARKED HOUR - TO - HOUR FLUCTUATIONS. A VERAGE LEVELS AND FLUCTUATIONS IN BOTH DAY AND NIGHT THEN INCREASE DURING LATE PUBERTY, BEFORE DECREASING SOMEWHAT IN THE ADULT. LH CONCENTRATIONS ARE IN MILLI -IU S PER MILLILITER OF BLOOD ( SEE F IG. 3-2.)

Copyright © 2006, Elsevier Inc. All rights reserved F IGURE 6-10 A VERAGE AGE OF MENARCHE, 1790 TO 1980., U NITED S TATES ;, VARIOUS E UROPEAN COUNTRIES. T HE REGRESSION LINE REPRESENTS THE AVERAGE RATE OF DECREASE, WHICH HAS BEEN 3 TO 4 MONTHS PER DECADE. T HE AVERAGE AGE OF MENARCHE IN THE U NITED S TATES IN THE LATE 1990 S WAS 12.3 YEARS, WHICH APPEARS TO BE STABLE AT PRESENT. A GE OF MENARCHE HAS NOT BEEN DECREASING IN UNDERDEVELOPED COUNTRIES, PROBABLY BECAUSE OF MALNUTRITION.