Terms in this set (5)
Describe the mechanisms by which the kidneys remove hydrogen ions from the body.
The mechanism by which kidneys remove hydrogen occurs when sodium ions are reabsorbed from the filtrate in exchange for Hydrogen ion by an antiport mechanism in the apical membranes of cells lining the renal tubule. Then the cells produce bicarbonate ions that can be shunted to peritubular capillaries. Next when CO2 is available, the reaction is driven to the formation of carbonic acid, which dissociates to form a bicarbonate ion and a hydrogen ion. Finally, the bicarbonate ion passes into the peritubular capillaries and returns to the blood. The hydrogen ion is secreted into the filtrate, where it can become part of new water molecules and be reabsorbed as such, or removed in the urine.
Explain the function of the myometrium and endometrium.
a)The Endometrium's main function is to provide a proper site of implantation for the fertilized egg. It can do this because of the two layers that make up the endometrium, the stratum functionalis and stratum basilis. The stratum functionalis grows and thickens when there is an increased level of estrogen and progesterone. This provides and adequate site for a fertilized egg to imbed itself in. If there is no fertilized egg, then the stratum functionalis will shed and stratum basilis will become the new stratum functionalis, providing a new site of implantation for the next egg.
b)The myometriums main function is to allow for uterine contractions during labor. This is possible This is possible through the increasing ratio of estrogen to progesterone that make the myometrium more sensitive to stimuli that promote contractions. While the anterior pituitary has begun its secretion of oxytocin the myometrium will begin to show more receptors for that hormone. This will lead to a positive feedback loop and ultimately lead to a greater contraction force that will allow for expulsion of the fetus
A 38-year-old male is upset about his low sperm count and visits a "practitioner" who commonly advertises his miracle cures of sterility. The practitioner is a quack who treats conditions of low sperm count with megadoses of testosterone. Although his patients experience a huge surge in libido, their sperm count is even lower after hormone treatment. Explain why.
The individual experienced a huge surge in libido because testosterone stimulates the brain and awakens the sex drive. The sperm count is even lower after the hormone treatment because the excess testosterone has negative feedback effects on that reduce the secretion of gonadotropin releasing hormone. This ultimately leads to a reduction of Leutinizing hormone and follicle stimulating hormone, which are necessary for spermatogenesis.
Define Braxton Hicks contractions.
Braxton hicks contractions are also known as false labor and are Intermittent painless contractions of the uterus that may occur every 10 to 20 minutes. They occur more frequently toward the end of pregnancy and are sometimes mistaken for true labor signs.
Explain what triggers a baby's first breath.
There are several factors that contribute to a baby's first breath. First labor contractions temporarily constrict umbilical blood vessels, reducing oxygenated blood flow to the fetus and elevating carbon dioxide levels in the blood. High carbon dioxide levels cause acidosis and stimulate the respiratory center in the brain, triggering the newborn to take a breath. The first breath typically is taken within 10 seconds of birth, after mucus is aspirated from the infant's mouth and nose. The first breaths inflate the lungs to nearly full capacity and dramatically decrease lung pressure and resistance to blood flow, causing a major circulatory reconfiguration. Pulmonary alveoli open, and alveolar capillaries fill with blood. Amniotic fluid in the lungs drains or is absorbed, and the lungs immediately take over the task of the placenta, exchanging carbon dioxide for oxygen by the process of respiration.