Oxytocin

Question 1

 It is a mammalian hormone that also acts as a neurotransmitter in the brain.
 It is best known for its roles in female reproduction: it is released in large amounts after distension of the cervix and vagina during labor, and after stimulation of the nipples, facilitating birth and breastfeeding, respectively.
 Recent studies have begun to investigate oxytocin’s role in various behaviors, including orgasm, social recognition, pair bonding, anxiety, trust, love, and maternal behaviors.

Answer 1

Oxytocin

Question 2

Oxytocin is made in ___________ _____________ cells of the supraoptic and paraventricular nuclei of
the hypothalamus and is stored in __________bodies at the axon terminals in the posterior pituitary.

Answer 2

magnocellular neurosecretory; Herring

Question 3

 It is then released into the blood from the _________ (neurohypophysis) of the pituitary gland.

Answer 3

posterior lobe;

Question 4

also made by some neurons in the paraventricular nucleus that project to other parts of the brain and to the spinal cord.

Answer 4

Oxytocin

Question 5

in lactating (breastfeeding) mothers, oxytocin acts at the mammary glands, causing milk to be ‘let down’ into a collecting chamber, from where it can be extracted by compressing the areola and sucking at the nipple. Sucking by the infant at the nipple is relayed by spinal nerves to the hypothalamus.

Answer 5

Letdown reflex

Question 6

important for cervical dilation before birth and causes contractions during the second and third stages of labor. Oxytocin release during breastfeeding causes mild but often painful uterine contractions during the first few weeks of lactation. This also serves to assist the uterus in clotting the placental attachment point postpartum.

Answer 6

Uterine contraction

Question 7

Due to its similarity to vasopressin, it can reduce the excretion of urine slightly. More importantly, in several species, oxytocin can stimulate sodium excretion from the kidneys (natriuresis), and in humans, high doses of oxytocin can result in

Answer 7

hyponatremia

Question 8

Modulation of _______________________________ activity. Oxytocin, under certain circumstances, indirectly inhibits release of adrenocorticotropic hormone and cortisol and, in those situations, may be considered an antagonist of vasopressin.

Answer 8

hypothalamic-pituitary-adrenal axis

Question 9

Oxytocin is relatively safe when used at recommended doses. Potential side effects include:
 Central nervous system:

Answer 9

Subarachnoid hemorrhage, seizures

Question 10

Potential side effects include:
Increased heart rate, decreased blood pressure, systemic venous return, cardiac output, and arrhythmias.

Answer 10

Cardiovascular

Question 11

Oxytocin is relatively safe when used at recommended doses. Potential side effects include:
Impaired uterine blood flow, pelvic hematoma, tetanic uterine contractions, uterine rupture, postpartum hemorrhage.

Answer 11

Genitourinary