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Growth And Its Measurement

Methods Of Measuring Growth

Supine Length (unable to stand → infant's length)

Standing Height

Body Mass → Amount of Organic Matter [Dry Mass → Plants]

Absolute Growth and Growth Rate

Advantages and Disadvantages of Cross-Sectional Study

Longitudinal Study

Relatives rates of growth of tissues and organs from birth to adulthood


Physical And Endocrine Changes Associated With Puberty

The Role Of Hormones In Controlling Early Growth

Table 16-3-1: Summary of hormones controlling growth
Name of Hormone Site of Release Actions
Somatotropin Anterior pituitary gland Stimulates mitosis, protein synthesis
Thyroxine Thyroid gland Stimulates rate of metabolism
Gonadotrophins Anterior pituitary gland (situated under brain)
- FSH - Development of follicle/egg cells and oestrogen secretion by follicle cells in ovaries
- ICSH - Spermatogenesis in testes
- LH (females) - Triggers ovulation, forms corpus luteum, thickens uterus lining, produces milk in breasts
- LH (males) - Secretion of testosterone by testes
Oestrogen Ovaries - Growth of 2° sexual characteristics - Thickening of uterus lining
Progesterone Corpus luteum - Growth of breasts - Increases blood supply to uterus lining
Testosterone Testes - Growth of 2° sexual characteristics - Sperm production
Table 16-3-2: Changes associated with puberty
In Boys In Girls Hormonal Stimulation In Boys In Girls
Testes Ovaries, Oviduct, Uterus, Vagina ICSH (boys) FSH (girls) Growth hormones Testosterone Oestrogen
Body growth Breasts Growth hormones Testosterone Oestrogen + Progesterone
Facial Hair, Larynx Pelvic girdle Testosterone Oestrogen
Pubic and axillary (underarm) hair Pubic and axillary (underarm) hair Testosterone Oestrogen
First menstrual flow (menarche) Oestrogen + Progesterone