Parturition & Uterine Physiology Flashcards
Describe the layers of the Uterus from superficial to deep
- Perimetrium (serous epithelium)
- Myometrium
- *Junctional Zone
- Endometrium
- Uterine cavity
What are the (3) sub-sections of the Uterus?
- Fundus
- Body
- Cervix
What are the sections of the cervix?
How do they differ between Nulliparous & multiparous women?
Supravaginal (internal) cervix:
Vaginal (External) cervix:
Nulliparous: appears circular
Multiparous: appears as a transverse Slit
What are the nerves associated with sympathetic (adrenergic) innervation?
Associated spinal nerves?
What ganglion do they synapse at?
Lumbar Splanchnic Nerves: T12, L1, & L2.
Synapse at the Inferior Mesenteric Ganglion
What are the nerves associated with Parasympathetic (Cholinergic) innervation?
Associated spinal nerves?
Pelvic n. S2, S3, & S4.
Through which plexus do the sensory, sympathetic, & parasympathetic nerves pass through?
Hypogastric Plexus
Parasympathetic (Cholinergic) nerves innervate what location?
Cervix
Sympathetic (Adrenergic) nerves innervate what locations?
Fallopian tubes
Cervix
Vagina
Sparse in uterine corpus & fundus.
The myometrium is composed of what (3) layers?
Tunica Muscularis;
- Stratum Supravasculare
- Stratum Vasculare
- Stratum Subvasculare
How are the muscle fibers at the fundus are primarily oriented?
Mosltly Longitudinal
How are the muscle fibers at the corpus (body) are primarily oriented?
Longitudinal & Oblique
How are the muscle fibers at the Cervix are primarily oriented?
Circular
In the absence of Calcium, caldesmon binds what?
Does this result in contraction or relaxation?
Caldesmon binds to Actin, resulting in relaxation
Activation of PKC results in phosphorylation of what?
Does this result in contraction or relaxation?
PKC phosphorylates Myosin LC, resulting in Relaxation.
PKC is an antagonist of MLCK*
Presence of Calcium acts on what?
Does this result in contraction or relaxation?
Calcium + Calmodulin bind to & activate MLCK;
MLCK then phosphorylates Myosin LC, resulting in contraction.
In addition, Calcium-Calmodulin binds to Caldesmon, keeping it from binding to Actin.
Calcium promotes contraction
Calcium channel blockers have what effect on uterine smooth muscle?
Calcium channel blockers relax muscle by inhibiting calcium influx through voltage-operated changes (VOC’s) & Receptor-operated Channels (ROC’s).
What signaling molecules result in relaxation of uterine smooth muscle? (3)
- CRH
- B2-Sympathomimetics
- Prostaglandin E2
What signaling molecules induce contraction of uterine smooth muscle? (3)
- Oxytocin*
- Thrombin
- Prostaglandin F2a
What changes do the changes in Estrogen & Progesterone cause in the myometrium?
- Changes in the Velocity & timing of action potentials
- Changes in membrane potentials
- Hypertrophy & hyperplasia of the myometrial cells
- Increased sensitivity of the myometrium
- Alteration in the arrangement of muscle bundles
- Development of the Sarcoplasmic Reticulum
- Increased number of mitochondria
During Ripening Phase 1,
