1. Physical Changes and Maturation of Systems: Please briefly describe the biological maturations that are happening in each body system (focus on what is changing instead of what is staying the same, and make sure to include the changes of puberty): (10 points)

Basal metabolic rate slows during puberty (Slightly higher basal metabolic rate in boys than girls); Basal body temperature gradually decreases with age and reaches adult levels around 12yo (slightly later in boys)

System Biological Maturations
Reproductive Puberty occurs during the adolescent years d/t CNS inhibitor mechanism during childhood years. The fundamental biological change during adolescence is puberty, in which the precise mechanism is not fully understood. Puberty is a predictable sequence of hormonal and physical changes with sexual changes and physical growth triggered by hormones controlled by the anterior pituitary gland (stimulates and produces FSH & LH) in response to stimulus from the hypothalamus (gonadotropin-releasing hormone-GnRH). FSH in females causes growth of ovarian follicles and production of estrogen. LH in females causes ovulation, forming of the corpus luteum, and production of progesterone. In males, LH causes testicular maturation and testosterone production; FSH with LH cause sperm production; estrogen, progesterone, and other androgens released from the gonads causes biological changes in muscles, bones, skin, and hair follicles.

Primary sexual characteristic in girls is development and release of an ovum from the ovaries every 28 days. Normal vaginal discharge is associated with uterine development and preparing for menstration.
Building of an endometrial lining of the uterus and first menarche (10.5 to 15.5 yo). A mature follicle release an ovum, ovulation as puberty progresses. Estrogen causes G&D of the vagina, uterus, fallopian tubes, and the skin of labia majora, breast areola, and nipples to grow and darken. Breast enlargement (development of a small bud of breast tissue 8-13yo) is d/t estrogen as well as pubic hair and axilla hair growth (2-6 mos following initial breast development) pigmentation of genital skin, and widening of the hips. Menarche occurs 2 years after breast bud appearance and average age is 10.5-15.5 yo.

In males the first pubescent changes are testicular enlargement accompanied by thinning, reddening, and increasing looseness of the scrotum at 9.5-14yo. (see Tanner stages for age of height spurt, penis growth, testis, pubic hair) Primary sexual characteristics is the development of viable sperm d/t FSH acting on testicular cells. FSH&LH cause an increase in production & secretion of testosterone. Breast enlargement and tenderness is common during midpuberty. Testosterone and other androgens have a direct impact on growth of the penis, scrotum, prostate, and seminal vesicles of the testicles as well as rapid increase in muscle mass, skeletal growth, bone age and bone density.

An adolescent should be considered potential fertile with 1st menstruation/ 1st ejaculation. In both sexes androgens are responsible for development of pubic, axillary, facial, and body hair. Increased androgen activity causes acne, body odor, deepening of voice, height spurt (see Tanner stages for age), and increase in RBC levels.
Respiratory Lungs increase in both diameter and length during puberty, RR steadily decreases throughout childhood to eventually reach adult rate in adolescence (At 7-12yo, RR at rest- 19-21 breaths/min; At 13-19yo, RR at rest- 16-18 breaths/min)
Cardiac HR decreases (At 7-12yo, HR at rest- 70-110 beats/min; At 13-19yo, HR at rest- 55-90 beats/min) and the size of the heart, blood volume (higher in boys than girls), and systolic BP (At 7-12yo, BP- 100-120/60-75; At 13-19yo, BP- 90-120/65-85)increases; girls have a slightly higher pulse rate and slightly lower systolic BP than boys; formed elements of the blood are reached (i.e. serum Fe, HH, RBCs)
Musculoskeletal Final 20-25% of linear