The role of oxytocin at birth and the use of artificial hormones in induction of birth.
Nutrition of the new-born (Consideration of the nutrition of the new-born should include the presence of antibodies in colostrum and breast milk and some reference to the possibility of chemical contamination of colostrum and breast milk).
The pattern of growth after birth
The major stages of the growth curve, including changes in body proportions.
The role of growth hormone (The general effects of growth hormone on the growth process should be considered, but microscopic details of bone structure or bone growth are not required).
The major body changes in males and females at puberty.
Hormonal changes and development in males and females at puberty.
15/12/16
Mrs Smith Ch18 Birth & Post-natal development
Learning Intentions
Understanding how the embryo develops inside the uterus and effects that the uterine environment can have on this development
Success Criteria
Explain the role of oxytocin at birth and the use of artificial hormones in induction of birth
Describe how the new born infant is nourished
To find out about the composition of colostrum
15/12/16
Mrs Smith Ch18 Birth & Post-natal development
Image source: images.doctorberlin.com
Birth
A human pregnancy lasts for about 38 weeks.
After the full period of gestation when the foetus is described as ‘full term’. Gentle contractions of the uterus move the foetus into the birthing position, with the head close to the cervix (PATURITION).
15/12/16
Mrs Smith Ch18 Birth & Post-natal development
Labour is brought on by the hormone oxytocin, which is secreted by the mother’s posterior pituitary gland. This hormone stimulates involuntary rhythmic contractions of the uterine wall, which start at the top of the uterus and work their way downwards in waves.
Anterior
(front)
lobe
Labour
Labour is brought on by the hormone oxytocin, which is secreted by the mother’s posterior pituitary gland. This hormone stimulates involuntary rhythmic contractions of the uterine wall, which start at the top of the uterus and work their way downwards in waves.
During the early stages of labour the amniotic sac bursts (waters break) and the cervix gradually dilates (opens). The contractions become stronger and come more often until eventually the baby is expelled from the uterus and delivered through the vagina.
15/12/16
Mrs Smith Ch18 Birth & Post-natal development
Induced Birth
Nowadays, birth can be artificially induced by gradually injecting synthetic oxytocin (or a hormone which mimics its effect) into the mothers bloodstream.
15/12/16
Mrs Smith Ch18 Birth & Post-natal development
Birth: Summary!
Oxytocin:
Produced by pituitary gland.
Brings about uterine contractions during labour.
stimulates contractions of mammary gland muscle tissue resulting in milk ejection.
Labour can be induced by injection of oxytocin.
15/12/16
Mrs Smith Ch18 Birth & Post-natal development
Nutrition of the Newborn
Lactation
Following parturition (the baby getting into position for birth) the hormone prolactin the mothers mammary glands become enlarged ready to produce milk. For milk to be released from the breasts– lactation the hormone oxytocin must be released.
As well as stimulating the uterine contractions during labour, oxytocin stimulates contraction of muscle tissues in the mammary glands causing milk to be released.
15/12/16
Mrs Smith Ch18 Birth & Post-natal development
Nutrition of the Newborn
Colostrum
Colostrum “mother-milk” is a yellow liquid produced by mammary glands a few hours after birth. It is the first milk the baby receives.
Colostrum is not only a source of protein, carbohydrate, fat, vitamins and minerals which are important for growth but it is also rich in maternal antibodies so gives the baby passive immunity against many diseases.
15/12/16
Mrs Smith Ch18 Birth & Post-natal development
A few days after birth normal breast milk is produced, which has fewer antibodies than colostrum but is richer in lactose sugar and fat.
Nutrition of the Newborn
15/12/16
Mrs Smith Ch18 Birth & Post-natal development
If a baby it not breastfed
Some mothers choose not to or find it too difficult to breast feed and instead feed their baby with powdered cow’s milk. This is also rich in the nutrients needed (especially proteins & minerals) by newborns. However this lacks the antibodies needed to protect the baby until it’s own immune system develops.
FYI – breast milk contains many more essential vitamins and minerals to support healthy development
15/12/16
Mrs Smith Ch18 Birth & Post-natal development
Babies do not get an adequate supply of iron from milk. Instead, they make use of iron stored during gestation (pregnancy) until they begin to eat solid foods at about 6 months.
Iron is an essential part of our diet because it is needed to:
Foods rich in iron:
Make many enzymes (e.g. catalase)
Make cytochrome (for aerobic respiration)
Form part of the haem group in haemoglobin
Nutrition of the Newborn
Iron
15/12/16
Mrs Smith Ch18 Birth & Post-natal development
Contamination of Breast Milk Organochlorides.
Organochlorides are non-biodegradeable chemicals used in pesticides on crops.
These can increase in concentration along the food chain and so are abundant in the final consumers (e.g. large fish, birds of prey, humans).
Stored in fatty tissue (these molecules are fat-soluble) including breast milk!
Excessive concentrations of these chemicals have been found in breast milk (so high it exceeds legal limits for commercially produced foodstuffs), fortunately there are no known cases of babies becoming ill from this. Many of these chemicals (e.g. DDT) are now banned in many countries
15/12/16
Mrs Smith Ch18 Birth & Post-natal development
A mini-clip: DDT in umbilical cords, it’s not a giant leap to assume there is traces in breast milk!
15/12/16
Mrs Smith Ch18 Birth & Post-natal development
Nutrition: Summary
Prolactin stimulates lactation Oxytocin is needed to release the milk.
Colostrum – first milk. Yellowish fluid rich in antibodies.
Normal breast milk – fewer antibodies, rich in lactose and fat. May contain organochlorides from mother’s diet
15/12/16
Mrs Smith Ch18 Birth & Post-natal development
Task: Torrance-TYK pg131 Qu’s 1&2
15/12/16
Mrs Smith Ch18 Birth & Post-natal development
Task: Torrance AYK pg135 Qu’s 1
15/12/16
Mrs Smith Ch18 Birth & Post-natal development
Learning Intentions
Understanding the pattern of growth after birth and the influences of hormones on this.
Success Criteria
Plot and interpret a human growth curve
Stat that body proportions vary through development from foetus to adult
Explain the role of growth hormone during normal development and the consequence of underproduction /overproduction. To study the effects of steriod use
Summarise
The major changes in males and females at puberty.
The hormonal changes in males and females at puberty.
15/12/16
Mrs Smith Ch18 Birth & Post-natal development
Growth After Birth
Measured as weight or height against time.
When graphed this is called a growth curve.
15/12/16
Mrs Smith Ch18 Birth & Post-natal development
Growth Curve
When drawn as a graph, growth takes the form of a curved line, thus is called a growth curve. It contains two phases of rapid growth called growth spurts! This is a sigmoid (S-shaped) curve.
Accelerating amino acid transport into bone and soft tissue cells.
This in turn particularly enhances growth of bones (especially the long bones of the body in the arms and legs) and cartilage.
Stimulating the breakdown of fats for energy release allowing rapid synthesis of proteins.
15/12/16
Mrs Smith Ch18 Birth & Post-natal development
15/12/16
Mrs Smith Ch18 Birth & Post-natal development
Pituitary Dwarfism
An under-production of GH during adolescence leads to a reduction in growth
Nowadays if a child is diagnosed with this condition they can be treated.
15/12/16
Mrs Smith Ch18 Birth & Post-natal development
Pituitary Dwarfism in the German Shepherd Dog
15/12/16
Mrs Smith Ch18 Birth & Post-natal development
Treatment for Dwarfism
As the production of somatotrophin is controlled by a gene, scientists have used genetic engineering to transfer this gene into a bacterium to produce human growth hormone. The hormone is then extracted and used to treat children who show the early signs of pituitary dwarfism.
15/12/16
Mrs Smith Ch18 Birth & Post-natal development
Giantism
An over-production of GH during adolescence leads to an abnormal increase in growth, especially in the long bones.
15/12/16
Mrs Smith Ch18 Birth & Post-natal development
Acromegaly
Acromegaly occurs in about 6 of every 100,000 adults. It is caused by abnormal production of growth hormone after the skeleton and other organs finish growing.
Growth hormone normally decreases once adolescence is completed.
If excessive GH production occurs in adulthood, an abnormal increase in the bones of the hands, feet and jaw (not the long bones) occurs
15/12/16
Mrs Smith Ch18 Birth & Post-natal development
Body Changes at Puberty
The second growth spurt occurs at puberty.
Until this stage the sex organs remain dormant, at puberty the sex organs become functional and a child changes into an adult. Males tend to reach puberty later than females. During puberty the body changes to develop secondary sexual characteristics.
Primary sexual characteristics (e.g. possession of male/female genitals) occur at birth
15/12/16
Mrs Smith Ch18 Birth & Post-natal development
Secondary sexual characteristics – happen during adolescence/puberty
Changes in males
Changes in females
Growth in height and weight
Growth in height and weight
Maturation of sex organs i.e. testes, scrotum and penis
Maturation of sex organs i.e. uterus, oviduct and vagina
