Page 156 - 86 human physiology part-2

Development: Birth Through Death

Growth and development

Growth is physical change and can be weighed and measured. Development is pyschological and
social. It's behaviors and thinking patterns. Growth and development work hand in hand to affect the
whole person. (We can not simply speak we must also have the physical structure to support that
speech.

Growth and development is happening from the time of fertilization until the day we die. This
process ranges from being fairly simple to very complex. It also happens in a certain order; for
example, we first learn to hold our heads up, then move our arms, use our hands, then comes crawling,
and finally walking. Growth and development occurs in stages and must complete stage one before
going to the next stage. Each stage is important and needed to get our bodies ready for the next stage.

The rate at which we grow and develop is not a constant. The rates change. Growth is a lot more
rapid in infants than in any other age. Children can have growth spurts, some developing quicker than
others, and it varies from individual to individual.

Hormonal causes of growth

The following chart summarizes hormones that regulate growth. Chapter 14, The endocrine system
has more information on this topic.

PRODUCTION
HORMONE ACTION REGULATION
SITE
Promotes protein Stimulated by GH-RH
synthesis and growth;
GH Growth Hormone Anterior pituitary Growth Hormones -
lipolysis and increased Releasing Hormones
blood glucose
Inhibited by somatostatin
Stimulated by TRH
TSH Thyroid Stimulating Anterior Pituitary Stimulates secretion of Thyrotropin-releasing
Hormone thyroid hormones
hormone
Inhibited by thyroid
hormones.
FSH Follicle Stimulating Promotes gamete Stimulated by GnRH
Hormone and LH Anterior Pituitary production and sex steroid Gonadotropin-releasing
Luteinizing Hormone hormone secretion hormone
Inhibited by sex steroids

Age of
Reflex Stimulation Response Function
disappearance
This reflex
Bright light shinning
Eye blink in eyes or clap hands closes eyelids Permanent protects the
infant form a lot
quickly
by eyes
of stimulation

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