reproduction

Implantation

The process where the embryo bores into the endometrium, which grows over the blastocyst.

Nutrition during early pregnancy

The embryo gains nutrition directly from the endometrium for the first 2-4 weeks.

Placenta

The structure formed from embryonic tissue that interacts with the endometrium to facilitate gas exchange, nutrient transfer, and waste removal.

Role of Human Chorionic Gonadotropin (hCG)

Maintains estrogen and progesterone levels in pregnancy.

Effects of high progesterone levels

Stimulates the formation of a mucous plug in the cervix, growth of the placenta, enlargement of the uterus, and cessation of ovulation and menstruation.

2nd Trimester Fetal Development

Rapid growth occurs, the fetus becomes active, and the pregnancy becomes visibly obvious.

3rd Trimester Characteristics

The fetus reaches approximately 50 cm in length, and labor is induced by hormones.

Oxytocin

Hormone secreted during labor that induces contractions of the uterus and stimulates prostaglandin secretion.

Filtration osmolarity in kidneys

Filtration from the Bowman's capsule to the proximal tubule has an osmolarity of about 300 mosm/L.

Juxtaglomerular apparatus (JGA)

Specialized tissue that releases renin to regulate blood pressure, volume, and sodium concentration.

Antidiuretic hormone (ADH)

Hormone that enhances fluid retention by increasing water permeability in the distal tubule and collecting duct.

Renin-angiotensin-aldosterone system (RAAS)

A regulatory mechanism that increases blood pressure and volume by promoting sodium and water reabsorption.

Atrial natriuretic factor (ANF)

Hormone that opposes RAAS, released by the heart in response to increased blood pressure and volume.

Organogenesis

The process of organ development that occurs during the first trimester of pregnancy.

Fetus at 8 weeks

All major organs are formed, marking the end of embryonic development.

Normal osmolarity range

The normal osmolarity for blood is approximately 300 mosm/L.

Distal tubule osmolarity

Osmolarity decreases to approximately 100 mosm/L as it flows through the distal tubule.

Collecting duct osmolarity

In the collecting duct, osmolarity can increase to approximately 1200 mosm/L as filtrate loses water.