Physiology_dept. Unical

PREGNANCY & LACTATION
Pregnancy is one of the most coordinated physiological processes known to science. It begins when a fertilized egg implants into the lining of the uterus. From this moment, a remarkable hormonal symphony begins.
The early placenta releases hCG, which maintains the corpus luteum and keeps progesterone levels high to support the growing embryo. As pregnancy progresses, the placenta takes over production of progesterone and estrogen, ensuring uterine stability, suppressing contraction, and supporting fetal development.
These hormones also prepare the breasts for feeding. By late pregnancy, the mammary glands are fully developed, though milk production is suppressed by high estrogen and progesterone.
After childbirth, these hormones drop sharply, allowing prolactin to stimulate milk production. Meanwhile, oxytocin triggers the let-down reflex and helps eject milk during breastfeeding. The same oxytocin also causes uterine contractions, helping the uterus return to its pre-pregnancy size.
Lactation is maintained by a supply-and-demand cycle—frequent suckling increases prolactin and oxytocin, which increases milk production and release.
Pregnancy and lactation show how perfectly the body coordinates growth, nourishment, and maternal adaptation to support new life.

GLOMERULAR FILTRATION RATE
GFR na the speed wey your kidney dey take filter blood every minute. E show how well the kidney dey work. But how the body take maintain this rate steady? Na serious coordination dey happen behind the scenes.
First, the kidney get autoregulation. If blood pressure rise, the afferent arteriole go tighten small so that filtration no too high. If pressure drop, e go relax to allow more blood enter glomerulus. The tubuloglomerular feedback from the macula densa dey monitor sodium levels and adjust the arteriole accordingly.
When blood pressure fall too much, juxtaglomerular cells release renin. This hormone start the renin–angiotensin–aldosterone system (RAAS). Angiotensin II tighten the efferent arteriole, raise filtration pressure, and help maintain GFR.
Hormones like ANP, prostaglandins, and sympathetic stimulation also join regulate the process.
Kidney no dey joke—if GFR too low, toxins go build; if e too high, important nutrients go waste. So maintaining normal GFR na key to life.