14.0 Lactation and Neonatal Physiology Flashcards
What are the respiratory changes that occur post-partum?
<b>1) Lung needs ability to inflate</b><br></br>- Drainage of lung fluid<br></br>- Surfactant production<br></br><br></br><b>2) Lung needs adequate ventilation and perfusion</b>
What are the stimuli for post-partum respiratory changes?
1) Tying/cutting cord<br></br>2) Cold air<br></br>3) Sensory stimuli
What are the circulatory changes that occur post-partum?
1) ↓ pulmonary vascular resistance<br></br>2) ↑ pulmonary blood flow<br></br>3) Closure of foramen ovale<br></br>4) Initiation of closure of ductus arteriosus<br></br>5) ↑ systemic vascular resistance
What are the stimuli for post-partum circulatory changes?
1) pO₂<br></br>2) Pressure gradients<br></br>3) PGE<br></br>4) CT deposition
What are the main neonatal fuel reserves?
1) Glycogen (muscle + liver)<br></br>2) Fat
How long can fuel reserves maintain a neonate?
> 24hrs<br></br><br></br>(fat stores allow baby to last 3 days with minimal calorific intake)
What percentage of neonatal glucose is endogenously produced?
50-80%
What is immunity transferred to neonate?
Antenatally
Where does non-shivering thermogenesis occur?
Brown adipose
Why are premature babies less able to deal with post-partum stresses?
May not have had sufficient cortisol exposure to induce maturation of organs/physiology to deal with life
What hormones promote breast development?
Begins at puberty due to:<br></br>1) Ovarian oestrogen<br></br>2) Adrenal steroids<br></br><br></br>Continues after menarche in response to cyclic changes in ovarian steroids
What changes occur to breast tissue during pregnancy?
- Rapid growth + branching of terminal portions<br></br>- ↑ vascularity<br></br>- Formation of glandular acini
When does breast alveolar secretion commence?
2nd trimester (fully activated after birth)
What is required for the morphological and functional differentiation of breast tissue?
Range of hormones<br></br>Growth factors (IGF-1 + EGF)
What is the main energy source in milk?
Fat
What is colostrum?
Initial milk<br></br>Differs from mature milk:<br></br>- Less fat + lactose<br></br>- More proteins, Ig, and fat soluble vitamins (D,E,A,K)
What cells produce milk?
Alveolar epithelial cells
What are the 5 different pathways for milk secretion?
<b>1) Exocytosis</b><br></br>- Secretion of lactose and milk proteins (lactalbumin)<br></br><br></br><b>2) Lipid transfer</b><br></br>- For triglycerides<br></br><br></br><b>3) Apical transport</b><br></br>- For water, minerals and monosaccharides<br></br><br></br><b>4) Transcellular</b><br></br>- Immunoglobulins (IgG)<br></br><br></br><b>5) Paracellular</b><br></br>- Bulk flow down gradients<br></br>- WBCs
Define lactogenesis:
Onset of lactation
What hormone does lactogenesis depend on?
Prolactin<br></br><br></br>(also needs withdrawal of progesteron and oestrogen)<br></br><br></br>Prolactin gradually increases throughout pregnancy and stays high for 4-6weeks post partum
How do progesterone and oestrogen inhibit lactogenesis?
Oestrogen inhibits prolactin<br></br><br></br>Progesterone inhibits lactose synthetase <br></br><br></br>(levels of these hormones decrease rapidly following delivery of placenta)
Define galactopoiesis:
Maintenance of lactation
What is the mechanism of galactopoiesis?
Suckling the nipple starts several reflexes (mediated in the hypothalamus)
What are the consequences of the suckling induced reflexes in galactopoiesis?
<b>1) ↑ Prolactin</b> <br></br>- from ant. pituitary <br></br>- forms milk<br></br><br></br><b>2) ↑ oxytocin</b> -<br></br>- From post. pituitary<br></br>- causes contraction of myoepithelial cells around ducts → milk ejection<br></br><br></br><b>3) ↓ GnRH release</b><br></br>- Thus ↓ ovulation
Human infants express milk from the nipple by stripping out milk stored in the lactiferous sinus using their tongues and hard palates.<br></br>The baby __________ have to generate a negative pressure to <b>breast</b> feed.<br></br>The baby __________ have to generate a negative pressure to <b>bottle</b> feed
Human infants express milk from the nipple by stripping out milk stored in the lactiferous sinus using their tongues and hard palates.<br></br>The baby DOES NOT have to generate a negative pressure to <b>breast</b> feed.<br></br>The baby DOES have to generate a negative pressure to <b>bottle</b> feed
What is the percentage risk of transmitting HIV from mother to baby?<br></br><br></br>What is the additional risk from breast feeding?
20-25%<br></br><br></br><br></br>10-14% increase with breast feeding
