8. Changes at birth Flashcards
(18 cards)
What is required for neurological/reflex integration at birth?
Fully organised reflex pathways needed (e.g. suckling)
Reflex pathways must be established for basic functions to occur immediately after birth.
What happens to endocrine function before and after birth?
Mostly established before birth; fine-tuned postnatally
Hormonal adjustments continue after delivery to support growth and metabolism.
What is the role of the epidermal function at birth?
Skin becomes a barrier—critical after placental separation
This barrier is essential for protecting the infant from environmental hazards.
What is the consequence of the loss of the placenta?
Loss of passive nutrient/oxygen exchange
This change triggers the infant’s need for independent physiological functions.
What must the infant do post-birth regarding thermoregulation?
Maintain own heat using brown fat and vasoconstriction
Pre-birth, heat was lost via the placenta; now the infant must generate heat independently.
What is the condition of the intestinal and liver function pre-birth?
Immature pre-birth
Rapid activation is required for digestion, absorption, and other metabolic functions after birth.
What is the renal system’s function post-birth?
Begins excretion and regulates ions/glucose—critical for fluid/electrolyte balance
The kidneys must adapt quickly to manage waste and maintain homeostasis.
How does lung function transition at birth?
From fluid-filled to air-filled
Surfactant reduces surface tension and enables gas exchange necessary for survival.
What drives cardiovascular changes at birth?
Activation of lungs and systemic circulation needs
These changes are essential for adapting to life outside the womb.
What is the order of closure for umbilical circulation?
Umbilical arteries close first, then the vein
This sequence allows for the drainage of placental blood to the neonate.
What triggers vasoconstriction in umbilical arteries?
Cord stretch, cooling to <18°C, high O₂ tension
These factors lead to the closure of the umbilical arteries.
What are the chemical mediators involved in umbilical artery closure?
↓ PGE₂ synthase, ↑ Thromboxane, ↑ Serotonin
These mediators facilitate the physiological changes necessary for circulation adaptation.
What is the purpose of vascular shunts in fetal circulation?
Prioritise oxygen-rich blood to brain and heart before lungs and liver
This ensures essential organs receive adequate oxygen during fetal development.
What is the function of the ductus venosus?
Bypasses liver, sends blood from umbilical vein to IVC
This shunt allows oxygenated blood to bypass the non-functioning fetal liver.
What is the role of the foramen ovale?
Blood flows from RA to LA, bypassing pulmonary circuit
This adaptation is critical for redirecting blood flow in the fetus.
What does the ductus arteriosus do?
Shunts blood from pulmonary artery to aorta, after brain arteries branch off
This mechanism minimizes blood flow to the lungs before birth.
What ensures the brain receives the most oxygenated blood in fetal circulation?
Ductus arteriosus and foramen ovale
These structures prioritize oxygen delivery to the brain over other organs.
True or False: Lungs receive a maximal amount of blood pre-birth.
False
High resistance in the fetal lungs prevents significant blood flow before birth.
