BIOL 202 Lecture Notes - Thymus, Sebaceous Gland, Estrogen
Document Summary
Measures same person at regular intervals over a long period of time. Measurements taken at different times can be compared. People leaf study area/lose interest in being involved in investigation. Takes a long time to see a pattern/conclusion. Relatives rates of growth of tissues and organs from birth to adulthood. [graph] different parts of the body grow at different rates: head and brain develop first being 90% of its adult size by the age of 5. Before growth of bones and muscles in limbs. Thus, results in a change in body proportion: reproductive system develops latest remains below 20% until puberty, lymphoid tissues (appendix, spleen, thymus gland) reach max size before puberty. Different growth rates result in changes in shape during embryological and post-natal growth. Growth spurt occurs earlier in girls but is larger in boys. Sex hormones (testosterone; oestrogen + progesterone) cause: development of internal reproductive organs and 2 sexual characteristics.