Pregnancy and the reproductive system Flashcards
Define gonads and gametogenesis
- Gonads: organs that produce gametes (eggs or sperm)
* Gametogenesis: the generation of gametes
State the characteristics that develop with the onset of puberty
Female
• Deposition of fat, predominantly in breasts and hips
• Breast development
• Broadening of the pelvis and growth of axillary and pubic hair
Male
• Increased larynx size and deepening of the voice
• Increased muscular development
• Growth of facial, axillary, and pubic hair, and increased growth of body hair
State the components female reproductive system and their functions
- Vagina: Allows discharge of menstrual flow
- Cervix: Pathway of menstrual flow and sperms and parturition
- Uterus: Receives fertilised ovum or sheds superficial layer (menstruation)
- Endometrium: the mucous membrane that lines the uterus
- Fallopian tubes: Transport the ovum
- Ovaries: Produce hormones (oestrogen, progesterone)
State the components of the male reproductive system and their functions
• Penis and urethra: Conveys urine and seminal fluid
• Scrotum: Encloses and protects the testes
• Testes Produce sperm and hormone (testosterone)
• Vas deferens: Store and convey spermatozoa
• Epididymis: Store sperm
Prostate gland: Secrete an alkaline fluid that helps neutralise acidity of sperm
Understand the endocrine control of reproductive system
- During puberty the hypothalamus produces gonadotropin-releasing hormone (GnRH)
- The GnRH stimulates the anterior pituitary to produce the follicle simulating hormone (FSH) and luteinizing hormone (LH)
- FSH: stimulates gamete production (eggs maturation in females), (sperm in males)
- LH: stimulates production of hormones by the gonads (oestrogens and progesterone’s in females) (testosterone in males)
List the functions of testosterone and which organ it is secreted by
Secreted by:
Testes
Functions:
• Testes: Produce sperm
• Other body tissues: Enable development of secondary sexual characteristics
List the functions of oestrogen and which organ it is secreted by
Secreted by:
Ovaries
Function:
• Uterus: Proliferation of endometrial cells
• Mammary glands: Development of the mammary glands (ducts)
• Anterior pituitary & hypothalamus - Before ovulation, increased LH & FSH secretion. After ovulation, decreased LH & FSH secretion
• Other tissues: Enable development of secondary sexual characteristics
List the functions of progesterone and which organ it is secreted by
Secreted by:
Ovaries
Functions:
• Uterus: growth of endometrial cells and secretion of fluid from uterine glands
• Mammary glands: Development of the mammary glands (ducts)
• Anterior pituitary & hypothalamus - Before ovulation, increased LH & FSH secretion. After ovulation, decreased LH & FSH secretion
• Other tissues: Enable development of secondary sexual characteristics
List the functions of the human chorionic condition hormone and which organ it is secreted by
Secreted by:
Placenta
Functions
• Ovaries: increase progesterone secretion
Briefly describe the follicular stage of the menstrual cycle
- This phase starts when the period starts and ends when ovulation starts
- It involves the release of the follicle stimulating hormone which causes the ovaries to prepare for ovulation
- Follicles are fluid filled sacs containing eggs. During the menstrual cycle, there are multiple follicles at varying stages of development
- This follicle produces oestrogen as it grows
Briefly describe the proliferative stage of the menstrual cycle
- After the uterus lining is shed, the uterus responds to the oestrogen produced by the follicles to rebuild the lining
- The endometrium becomes thicker to prepare a place for a potential fertilized egg to implant and grow
Briefly describe the ovulation stage of the menstrual cycle
- When the largest follicle produces high enough levels of oestrogen, it signals the brain to increase its levels of the luteinizing hormone
- Luteinizing hormone stimulates egg release (ovulation)
- Largest follicle will be the one to be released during ovulation
Briefly describe the luteal stage of the menstrual cycle
- After ovulation the follicle that contained the egg transforms into something called acorpus luteumand begins to produce progesterone as well as oestrogen
- Progesterone levels peak, and these changes are associated with common premenstrual symptoms
- If an egg is fertilized, progesterone from the corpus luteum supports the early pregnancy
- No fertilization = corpus luteum starts breaking down, resulting in a drop in estrogen and progesterone levels. This causes menstruation
Briefly describe the secretory stage of the menstrual cycle
- Endometrium prepares to either support pregnancy or break down for menstruation
- The endometrium secretes prostaglandins that cause changes to other cells nearby, “PGF2α” and “PGE2”.
- They cause the uterine muscle to contract/ cramp which helps trigger the period
- If a pregnancy occurs, prostaglandin production is inhibited
- If pregnancy does not occur, the corpus luteum stops producing oestrogen and progesterone
- The drop in hormones, along with the effects of the prostaglandins, cause the blood vessels to constrict and tissue of the endometrium to break
Explain the process of fertilisation
- When a sperm reaches and fuses with the egg, it must capacitate: their membranes must become fragile and release hydrolytic enzymes
- The first sperm to make contact with the eggs membrane will capacitate and its will move into the cytoplasm of the egg
- The eggs nucleus and sperms nucleus fuse
- Meanwhile, the egg releases cortical granules into the extracellularly space to prevent the entry of other sperm
Appreciate the sex determination and differentiation
- The sperm decides the genetic sex: the presence of the Y chromosome = male
- The presence of the SRY gene the Y chromosome causes the development of the testes in males
Discuss how oral contraceptives work
- The pill: Synthetic versions of oestrogen and progesterone
- Mini pill: Synthetic version of progesterone only, used by patients who cannot take oestrogen
- Prevent ovulation by maintaining more consistent hormone levels
- Without a peak in estrogen, the ovary doesn’t get the signal to release an egg
- Causes thickened cervical mucus so the sperm cannot reach the egg
Understand the oral implications of contraceptives
- Can exacerbate inflammatory status
- Tendency toward gingival bleeding, gingival enlargement
- Dry socket after extraction
- Interact with antibiotics
Explain the positive feedback control using parturition as an example
- The first contractions of labour push the baby toward the cervix
- The cervix contains stretch-sensitive nerve cells that monitor the degree of stretching
- These nerve cells send messages to the brain, which in turn causes the posterior pituitary to release oxytocin
- Oxytocin causes stronger contractions of the smooth muscles in of the uterus, pushing the baby further down the birth canal
- This causes even greater stretching of the cervix
Explain the positive feedback control using lactation as an example
- During pregnancy oestrogen and progesterone, and other placental hormones inhibit prolactin-mediated milk
- It is not until the placenta is expelled that this inhibition is lifted
- The suckling action of an infant causes the brain to receive sensory input from the areola
- The brain releases prolactin, which leads to milk production; more suckling leads to more prolactin, which in turn leads to more lactation.
- Oxytocin stimulates myoepithelial cells to squeeze milk from the alveoli so it can eventually discharge through the nipple pores
List the oral changes during pregnancy
- Gingivitis and periodontitis: Hormones
- Swollen red gums that bleed easily: blood supply
- Pyogenic granuloma: caused by increased progesterone in combination with local irritants/bacteria
- Caries: food craving, frequent snacks and sweets
- Erosion: Morning sickness
- Prevention: rinse immediately, smear toothpaste over teeth, don’t brush immediately
List the oral changes during menopause
- Burning mouth syndrome
- Xerostomia
- Mucosal changes (menopausal gingivostomatitis)
- Abnormal pale dry or shiny erythematous appearance
- Pyogenic granuloma
- Trigeminal neuralgia
- Osteoporosis and periodontitis
- Eating disorders and caries
Discuss the precautions when managing a pregnant patient
- Dental treatment in the 2nd trimester is the safest time
- Be aware of drugs which could cross the placenta
- N2O is not recommended for pain management (birth defects)
- Avoid supine hypotensive syndrome in the 3rd trimester
- Dental X-ray can be taken at anytime BUT use of a lead drape is recommended
Understand the physiological effects of pregnancy
- Hormones increases in human chorionic gonadotropin, oestrogen, progesterone to maintain pregnancy
- Metabolic adaptations in pregnancy: increased metabolic rate, increased oxygen consumption, decreased insulin sensitivity
- Cardiovascular adaptations: increased blood volume, changes in blood pressure, cardiac output and haematocrit
- Respiratory changes in pregnancy: structural changes, increase in alveolar ventilation
- Renal changes in pregnancy: increase in renin, angiotensin II and aldosterone, increased filtration, increased water and sodium retention
