Physiology Of Labour

Front 1

Uterine contractions mediated by interaction of......

Back 1

actin and myosin.
sliding of the filaments MORE ON THIS

Front 2

Effect of Oxytocin and Gap Junctions

Back 2

binds to receptors on myometrium
receptor numbers increased due to effects of estrogen
increase in intracellular calcium facilitated by gap junctions

Front 3

Energy for contractions comes from...

Back 3

hydrolysis of ATP

Front 4

Intensity of contractions and Retraction

Back 4

upper segment contracts powerfully. intensity decreases from fundus down.
lower segment slightly contracts, almost absent, cervix dilates at lower segment

cells relax after each contraction due to removal of calcium but do not return to their original size.
retarction of cells leaves each cell shorter and fatter.

Front 5

Retraction Ring

Back 5

Physiologic Ridge between upper thick fibres and lower uterine segments. Contraction occur above and not below this ring.

Front 6

Relaxation of the uterus is important because...

Back 6

It allows for gas exchange and diffusion in the intervillous space and to avoid depletion of ATP

Front 7

Second stage contractions are...

Back 7

assisted by voluntary diaphragm and abdominal force. The woman holds her breath and her diaphragm goes down, and the abdominal muscles contract.

Front 8

Oxytocin receptors in labour are..

Back 8

Found in the myometrium, decidua, placenta and fetal membranes. The highest numbers of these are found in early labour. Receptors in the myometrium directly stimulate muscle contractions.

Front 9

Oxytocin is released by the __________ ___________ _______ in a ___________ manner. This is in response to _____________ stimuli from the _________, __________ and _________.

Back 9

Oxytocin is released by the posterior pituitary gland in a pulsatile manner. This is in response to neural stimuli from the uterus, cervix and vagina.

Front 10

Prostaglandins stimulate muscle contraction by...

Back 10

binding to the cell membranes in the uterus and increasing the frequency of action potentials allowing for greater calcium influx.

Front 11

Prostaglandin _________, E_ and E_ promote contractions by increasing ___ ________ formation.

Back 11

Prostaglandin F2alpha, E1 and E2 promote contractions by increasing gap junction formation.

Front 12

Estrogen levels rise beginning at __ weeks.

Back 12

36

Front 13

Estrogen promotes the formation of ___________ _________ ________ (___s) such as....

Back 13

Estrogen promotes the formation of contractile associated proteins (CAPs) such as oxytocin receptors, gap junctions and prostaglandin receptors.

Front 14

Estrogen is continuously secreted due to the effects of ___, which leads to the stimulation of the fetal _______ ______ to secrete _____, which in turn promotes the production of Estrogen. This is called ________ _________.

Back 14

Estrogen is continuously secreted due to the effects of CRH, which leads to the stimulation of the fetal adrenal glands to secrete DHEAS, which in turn promotes the production of Estrogen. This is called positive feedback.

Front 15

As the fetus passes into the vagina the maternal ______ is pushed ________ and the bladder is moved into the ___________ . Posteriorly the pelvic floor is pushed _______ and the rectum is __________.

Back 15

As the fetus passes into the vagina the maternal pelvis is pushed up and the bladder is moved into the abdomen. Posteriorly the pelvic floor is pushed down and the rectum is compressed.

Front 16

Fetal Cortisol stimulates...

Back 16

production of PGF2alpha and PGE2, placental CRH.