Module 2 Female Anatomy and Physiology Flashcards
***Describe the cascade of events that initiates labor focusing on the placenta, fetus, and maternal components.
What anatomical and physiologic changes occur to the cervix that are necessary for the onset and progress of labor?
The cervix undergoes dramatic changes during labour in a process known as ‘effacement’ or ‘ripening’. It starts out long and firm, and as labour progresses, it softens, widens and becomes more elastic. Changes to the cervix are partly triggered by contractions of the muscles of the uterus, which help open the cervix. Prostaglandins decrease the collagen content in the cervix to make it more elastic and thinner. Contractions cause the dilation (“opening”) and continued effacement (“thinning”) of the cervix through labor.
Describe the significance of progesterone in the onset and progression of labor.
Progesterone is part of Phase 0 (Quiescence), where uterine contractions are inhibited. This is a period late in pregnancy.
Onset: Progesterone is a central hormone leading to uterine quiescence. When progesterone dominates, labor onset it prevented.
Describe the significance of estrogen in the onset and progression of labor.
Estrogen plays a role in phase 1 of labor (activation). It helps to stimulate the upregulation of myometrial receptors prostoglandin for oxytocin and develop gap junctions to allow communication between muscle fibers (through gap junctions)
Onset: Plays a central role in activation of labor (phase 1). It is a uterotropin-a hormone that facilitates initiation of labor. Under the influence of estrogen, uterine myometrial cells express receptors for prostaglandins and oxytocin and is necessary for development of gap junctions.
Describe the significance of prostaglandins in the onset and progression of labor.
Prostaglandins facilitate uterine contractions and increase myometrial sensitivity to oxytocin and stimulate the formation of gap junctions.
Onset: Plays a role in labor activitation and acts as a uterotropin by increasing myometrial sensitivity to oxytocin and stimulating the formation of gap junctions
Progress: Promotes decreased collagen content in the cervix leading to cervical softening and effacement. Also produces by uterine decidua and promotes uterine contractions
Describe the significance of oxytocin in the onset and progression of labor.
Oxytocin is a potent uterotonic, stimulates lactation, increases sexual arousal, and promotes bonding.
Oxytocin is released by the hypothalamus and stimulates smooth muscle contractions. The change in oxytocin number and sensitivity affects the strength and frequency of contractions. It also serves to contract the uterus after delivery to prevent hemorrhage.
What is the myometrium?
Makes up the bulk of the uterus. Composed of bundles of smooth muscle fibers separated by connective tissue made primarily of collagen and elastin.
**Describe the myometrium and the myometrial contraction including the definition of the myometrium, the difference in myometrial activity in the activation vs. stimulation phase, the importance of changes in oxytocin receptor number and sensitivity, and the triple descending gradient of fundal dominance.
Myometrium: The bulk of the uterus is made up of the myometrium, which is composed of bundles of smooth muscle fibers separated by connective tissue made primarily of collagen and elastin. The muscle fibers of the myometrium are arranged in three distinct patterns that contribute to this tissue’s ability to contract effectively.
Describe the phase of parturition: quiescence, including which of the following hormones inhibit, activate, and stimulate uterine activity:
-progesterone
-estrogen
-prostaglandins
-oxytocin
Quiescence is the before the first phase of parturition cascade. It is a period late in pregnancy. Hormones that inhibit contractions in this phase are; progesterone, relaxin, nitric oxide.
Describe the phase of parturition: activation, including which of the following hormones inhibit, activate, and stimulate uterine activity:
-progesterone
-estrogen
-prostaglandins
-oxytocin
Activation is the first phase of parturition. This is where uterotropins (estrogen and prostaglandins) stimulate the upregulation of myometrial receptors (aka activate oxytocin receptors). This phase is characterized by a loss of progesterone.
Describe the phase of parturition: stimulation, including which of the following hormones inhibit, activate, and stimulate uterine activity:
-progesterone
-estrogen
-prostaglandins
-oxytocin
Stimulation is the second phase of parturition. This is where uterotonins (prostaglandins and oxytocin) promote labor progression. This is characterized by the onset of regular, progressive contractions.
***Describe the maternal physiologic adaptations to labor in regards to the hemodynamic, respiratory, hematologic and gastrointestinal systems; and maternal psychobiological responses to pain.
Can you draw or identify these pelvic parts?
1) ischial spine
2) ischial tuberosity
3) pelvic sidewall
4) pubic arch
5) sacral promontory
1) ischial spine= I
2) ischial tuberosity= M
3) pelvic sidewall= G
4) pubic arch= K
5) sacral promontory= D
Refer to study guide for associated photo if needed
Can you draw or identify these pelvic parts?
1) symphysis pubis
2) sacroiliac joints (called sacroiliac synchondroses in Varney)
3) sacrococcygeal symphysis
1) symphysis pubis= L
2) sacroiliac joints= F
3) sacrococcygeal symphysis= C
Refer to study guide for associated photo if needed
Can you draw or identify these pelvic ligaments?
1) sacrospinous
2) sacrotuberous
1) sacrospinous= O
2) sacrotuberous= N
Refer to study guide for associated photo if needed
