Chapter 10: Health Promotion of the Infant and the Family Proportional changes (*See Table 10-1)
Growth is very rapid in the initial 6 months
Infants gain 150 to 210 grams weekly until approx. 5-6 mos., when the birth weight has doubled Weight gain slows during the second 6 mos.
By 1 yr of age, birth weight has tripled
Infants who are breastfed beyond 4-6 mos. of age typically gain less weight than bottlefed infants Breastfed infants tend to self-regulate energy intake
increases by 2.5cm (1in.) a month during the first 6 mos. of life slows down during the second 6 mos.
Increases in length occur in spurts, rather than a slow, gradual pattern By 1 year of age, length has increased by 50%; occurs mainly in the trunk Head growth is rapid- reflects growth & differentiation of the nervous system increases approx.. 1.5cm/ month for 1st 6 mos.
declines to 0.5cm/mo for 2nd 6 mos.
Posterior fontanel closes by 6-8 wks.; anterior fontanel closes by 12-18 mos. Chest assumes a more adult contour, with the lateral diameter becoming larger than the anteroposterior diameter Heart grows less rapidly than rest of body
Maturation of Systems (*See Table 10-1)
Respiratory rate slows and is relatively stable; respiratory movements are abdominal Close proximity of trachea to bronchi and its branching structures transmits infectious agents easily Short, straight Eustachian tube allows infection to ascend from pharynx to the middle ear. Inability of immune system to produce IgA in mucosal lining provides less protection for infants against infection Heart rate slows; systolic pressure rises during 1st 2 mos; diastolic pressure decreases during 1st 3 mos. Fetal hemoglobin present for 1st 5 mos.- a common result at 2-3 mos of age is physiologic anemia Maternally derived iron stores present for 1st 5-6 mos.= accounts for lowered hemoglobin levels at age 6 mos. Digestive processes relatively immature at birth; majority of it do not begin functioning until 3mos. of age Gastric digestions consists of hydrochloric acid and rennin
Renin acts specifically on casein in milk to cause formation of curds; curds cause milk to be retained in stomach long enough for digestion occur Digestion also takes place in duodenum.
Amylase (ptyalin)- enzyme for carbs- deficient until 4-6 mos of age Lipase- enzyme for fat absorption deficient until 4-5 moss
Trypsin secreted in sufficient amounts to digest proteins
Stools signify immaturity of digestive system
solid stools during infancy are passed incompletely broken down in feces excess fiber intake causes loose, bulky stools
Stomach enlarges to accommodate more food
Infants vulnerable to diarrhea, vomiting, and dehydration
Liver is most immature of GI organs during infancy
Full-term newborns receive Ig G from mothers; confers immunity for 1st 3mos of life begin to synthesize during birth; reaches adult levels by 1 yr. of age IgM begins synthesizing at birth; reaches adult levels by 9mos. old IgA not present at birth; found in tears and saliva by 2-5 wks. present in large amounts in colostrum
confers protection in mucosal linings in GI tract
reaches adult levels during early childhood
Vernix caseosa- white, oily substance coats bodies of infants at birth abundant in groin and axilla
protects newborns from infections
Thermoregulation- the ability of the skin to contact and of muscles to shiver in response to cold capillaries constrict in response to cold, decreasing evaporative heat loss from skin surface capillaries dilate in response to heat, decreasing internal body temp. Total body fluid- at birth, 75% of term baby’s body weight is water Abundance of extracellular fluid
Loss of 5%-10% of initial birth weight in 1st 5 days is because of ECF contraction, enhanced renal tubular function, and rapidly increasing glomerular filtration rate Immaturity of renal structures predisposes infants to dehydration and electrolyte imbalance Complete maturity of kidneys occurs in latter half of 2nd year...
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