Puberty and Lactation Flashcards
What does puberty involve?
Physiological processes of gonadarche (maturation of gonads by gonadotrohins) and adrenarche (increase in production of androgens (sex hormones) by adrenal cortex)
What are the primary and secondary sexual characteristics?
Primary - formation of reproductive organs (present at birth)
Secondary - Develop during puberty but are not directly required for reproduction
Define;
- Thelarche,
- Pubarche,
- Menarche,
- Thelarche - Onset of breast development.
- Pubarche - First appearance of pubic hair.
- Menarche - Onset of menstruation
What is the hypothalamic-pituitary-adrenal axis?
Occurs at 6-8yeats and results in ACTH produced by pituitary. It causes stimulation of adrenal glands to secrete androgens (go on to cause pubarche, development of pilosebaceous units in skin and increases cortical bone density)
Describe the stages of female puberty
Breast development - first sign and can occur from 8.5 to 12.5 years.
Pubic hair and rapid height growth (tends to occur almost immediately after breast development).
Menarche - average 13 years old, above 2.5 years after start of puberty and signals the end of growth.
What are the hormone-dependant secondary sexual characteristics in girls?
- Facial, underarm and pubic hair,
- Thick secretions of skin oil glands,
- Female pattern of fat distribution,
- Hips and pelvis widen,
- Uterus and cervix enlarge, secretory function increases,
- Bone growth via hormone secretion then termination via closure of epiphyseal plates.
What are the stages of male puberty
- Testicular enlargement (first sign occurring between 10-15).
- Pubic hair growth and penile growth (normally 2 years after hair growth)
- Spermarche (appearance of sperm in seminal fluid)
- Growth spurt (when testicular volume is 12-15mls)
How is puberty initiated?
Sustained increase in pulsatile GnRH release due to a change in sensitivity of hypothalamic neurons. This occurs at night and leads to more pronounced gonadotrophin release
Name some factors that contribute to early puberty
- Genetics,
- Social factors (lower social class and obesity),
- Geographical factors (closer to the equator, lower altitudes and urban),
- Environmental exposures (endocrine disrupting chemicals),
- Race (earlier onset in black patients)
What are some of the benefits of breastfeeding for baby?
- Reduced incidence of GI, resp and middle ear infections,
- Decreased risk of childhood diabetes, asthma and eczema,
- Lower risk of lactose intolerance,
- Improved intellectual and motor development,
- Decreased risk of obesity,
- Reduced autoimmune disease,
- Reduced risk of sudden infant death syndrome
What are the benefits of breastfeeding for mum?
- Promotes recovery from childbirth,
- Promotes return to normal body weight,
- Period of infertility,
- Reduced risk of postmenopausal breast cancer,
- Reduced risk of ovarian cancer,
- Improves bone mineralisation
Explain the anatomy of the breast
- Nipple surrounded by pigmented skin called areola.
- Modified sebaceous glands empty via lactoferous sinuses which open up onto surface of nipple.
- Adipose tissue is dominant in non-lactating breast,
- Glandular tissue only fully develops during pregnancy
Describe features of secretory alveoli
Milk producing cells which are stimulated by prolactin
Describe features of each alveolus
Surrounded by myo-epithelial cells and stimulated by oxytocin
Describe the 5 major routes for milk production
1) Secretory pathways,
2) Transcellular endo/exo-cytosis,
3) Lipid pathways,
4) Transcellular salt and water transport through channels and transporters,
5) Paracellular pathway for ions and water
