Unformatted text preview: ium, and the limbs elongate as a result of
increasing ossification of cartilage. In the period up to
two years, infants also develop so that they can hold
their head up, sit up, crawl, and then walk. (a) Estrogen
(b) Prostaglandins, factors released from the
placenta (as its function becomes compromised
towards the end of pregnancy), and the
physiological state of the baby itself. 3. The second period of rapid growth occurs at puberty
in response to the rapid increase in secretion of sex
steroids and growth hormone. Each gender develops
their secondary sexual characteristics and there is a
second increase in height. 3. The umbilical cord continues to function (supplying
oxygen) until the baby is breathing on its own. 4 4. (a) Hormone: Oxytocin. Production: posterior pituitary.
(b) Hormone: Prolactin. Production: anterior pituitary.
(c) Hormone: Oxytocin. Production: posterior pituitary. (a) Growth velocity drops rapidly in the first two years
of life (although their absolute growth remains
(b) The graph infers that the rate of growth before
birth is very high.
(c) Between 12 and 14 years 5. Progesterone inhibits prolactin secretion. 5. 6. (a) and (b) any two of the following:
• It helps to form early, close contact between the mother and infant (bonding).
• Breast fed babies do not get too fat.
• The infant has better control over its own milk intake (said to prevent overeating in later life).
• Fats and iron from breast milk are better absorbed than those in cow’s and the milk is
easier to digest.
• The sodium (salt) content of human milk is lower than cow’s milk and more suited to infants needs.
• Breast feeding provides important antibodies that help prevent gut problems and improve immunity
to respiratory infections and meningitis.
• The act of sucking on the breast promotes development of the jaw, facial muscles, and teeth
(sucking from a bottle requires much less effort).
• There is less likely to be an allergic reaction to a mothers milk than to cow’s milk or to a formula.
• Breastfeeding helps the m...
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This document was uploaded on 01/28/2014.
- Winter '13