Physiology Flashcards
Is all active testosterone free?
NO! It is also active when bound to albumin because of its low affinity (hense high reactivity)
What are the phases of the menstrual cycle?
1. FOLLICULAR PHASE
Cycle days 1-5: Menses/ “period”
Cycle days 6-13 : Rise in estrogen
Cycle day 14 : Ovulation
2. LUTEAL PHASE
Cycle days 15-28 : implantation or not
What is RBC isoimmunisation?
Maternal antibodies formed against fetal erythrocyte antigens that cross the placenta and causes fetal red cell lysis and anemia
What is andropause or partial androgen deficiency in aging men (PADAM)?
- Free testosterone goes down faster with age than total because liver produces SHBG as you get holder, so high affinity binder increases, which causes more testosterone to become bound and there to be less free
- Symptoms: decreased testicular function, libido, muscle strength, increased BPH and prostate cancer, depression and hot flashes
- Treatment: testosterone, human growth hormone, DHEA and melatonin
- Side effects: retain fluids, worsen/precipitates sleep apnea, produces polycythemis
What are the stages of labour?
- First stage (cervical stage): cervical change – effacement & dilatation to 10 cms
- Second stage (pelvic stage): Begins at full dilatation of cervix till the delivery of the baby
- Third stage (placental stage): The third stage of labor involves the separation and expulsion of the placenta.
What are the normal values of progesterones?
Male: 0.3-1.3 nmol/L
Female: 19-45 nmol/L
What hormone is used for pregnancy test?
hCG (human choronic gonadotropin)
What are the respiratory effects of pregnancy?
- Deeper breathing à ↑ tidal volume
- Increased oxygen consumption (20%) by progesterone and enlarged uterus
- Increased ventilation rate (40%)
How is milk secretion controled?
Autocrine control based on the supply-demand principle
What triggers puberty?
Kisspeptin
What hormonal factors influence reproduction?
- Age
- Kisspeptin (+)
- MKRN3 (-)
- Nutrition
- Leptin (long-term)
- Insulin (short-term)
- Light
* Pineal input - Social factors
- Stress
- Breastfeeding (prolactin inhibits pulsatility)
Erection is under the contol of which system?
PARASYMPATHETIC
GnRH is regulated by what?
By a small protein in the hypothalamus called kisspeptin in a pulsatile way
If you have low sex steroids and high LH & FSH, you suspect what endocrine disease?
End-organ resistance to gonadal steroids caused by chromosomal abnormality, menopause, autoimmune condition or surgical/chemotherapy
What hormones peak during puberty?
- LH pulse amplitude is about 10 x that of childhood
- FSH pulse amplitude is about 2x that of childhood
The pulses peak in the NIGHT at first and then during the day as well
What are the MSK effects of pregnancy?
- Progressive lordosis
- ↑ mobility of sacroiliac, sacrococcygeal, and pubic joints have increased mobility during pregnancy
- Symphyseal separation (PAIN)
- Carpal tunnel syndrome-like symptoms
What part of the pituitary secreted the melanocyte stimulating hormone (MSH)?
The Pars Intermedia (Intermediate pituitary)
What are the normal values of estradiol?
Male: 37-360 nmol/L
Female: 700-1250 nmol/L
What are the normal values of testosterone?
Male: 6.9-34.7 nmol/L
Female: 0.7-2.8 nmol/L
When is the use of formula instead of breastfeeding indicated?
- Certain inborn errors of metabolism (galactosemia, PKU)
- Inadequate infant weight gain
- Use of maternal medications ie. anti-neoplastic agents
- Maternal HIV or active/untreated TB
Which cells produce the estradiol (estrogen) in the luteal phase?
- Theca interna cells produce androstenedione in response to LH stimulation
- Then granulosa cells convert androstenedione to estradiol when stimulated by FSH
What hormones increases proportionaly to placental mass during pregnancy?
hPL (human placental lactogen)
Ejaculation is under the conrol of which system?
SYMPATHETIC
What inhibits GH?
- Leptin
- Insulin-Like Growth Factor (IGF-1)
What are the gastro-intestinal effects of pregnancy?
- Hypertrophic gums (gingivitis gravidarum)
- Nausea and hyper-emesis in early pregnancy (hyperemesis gravidarum): hCG and E2 mediated
- Acid reflux
- Constipation
What stimulates GH?
- GH Releasing Hormone (GHRH)
- Estrogen
What are the main effects of progesterone during pregnancy?
- Reduces smooth muscle excitability (myometrium)
- Relaxes ureters, blood vessels, GI tract
- Brain effect
What hormone does not trigger but is essential to puberty?
Leptin
What causes the labour to start?
- Fetal cortisol levels
- Progesterone withdrawal
- Prostaglandin release
- Oxytocin stimulation
What are some effects of breastfeeding?
EVERYTHING
- Overall decreased morbidity and mortality
- Decreased risk of infections - respiratory, gastro, otitis, sepsis
- Establishement of a healthy infant microbiome
- Decreased risk of SIDS
- Decreased asthma, allergies and eczema
- Decreased risk of diabetes, obesity and hypercholesterolemia
- Increased development, cognition and IQ scores
- Decreased risk of childhood cancers, ie. lymphoma and leukemia
- Decreased risk of certain chronic disease, ie. celiac disease, juvenile arthritis
- Decreased risk of dental caries and malocclusion
- Enhanced mother-infant bonding
- Oxytocin release à decreased postpartum bleeding
- Earlier return to pre-pregnancy weight
- Decreased risk of breast, ovarian and endometrial cancer
- Decreased risk of cardiovascular events
- Simpler and cost-saving
- Contraceptive (< 6 months, every 4 hours, no menstrual bleeding)
If you have low sex steroids and low LH & FSH, you suspect what endocrine disease?
Hypogonadotropic hypogonadism (hypothalamic-pituitary failure)
Which hormone causes the Milk Ejection Reflex?
Oxytocin
What is the LH Surge effect on the Ovary?
- Oocyte in the dominant follicle completes 1st meiotic division
- Increase in local secretion of plasminogen activator and cytokines required for ovulation
- ****Oocyte released from follicle at ovarian surface ~ 36 hrs after LH surge*****
- Even before oocyte is released, granulosa cells around it begin to “luteinize” and produce progesterone. Progesterone slows LH pulses/ decreases LH pulse frequency
What can cause a deficiency in a receptor or in aromatase?
Osteoporosis, fertility issues and affected growth because of lack of ESTROGEN
What are the components of the hypothalamo-pituitary-testicular (HPT) axis?
What are the cardiovascular effects of pregnancy?
- Increase in blood volume (4 L → 5.5 L)
- Decrease in iron stores (BM, liver, spleen)
- Increase in cardiac output: stroke volume (20%), heart rate (15%)
- Decreased peripheral resistance
- Redistribution of blood flow to kidneys, uterus
What are the hematological effects of pregnancy?
- Development of hypercoagulable state (estrogen mediated): Increased risk of DVT and PE
- Increased leucocyte count: Increased risk of infection
- Varicosities
What hormones are involved in lactogenesis?
- Prolactin: nipple growth and milk secretion after birth (MAIN HORMONE)
- Human placental lactogen: areolar growth
- Estrogen: proliferation and differentiation of ductal system (ductular sprouting)
- Progesterone: growth/development of lobes and alveoli
What are the main effects of estrogen during pregnancy?
- Increases uterine size and blood flow
- Softens connective tissue
- Breast development (along with PRL)
- Fluid retention
What are the 2 products made by testosterone?
- Dihydrotestosterone (DHT) by 5a-reductase
- Estradiol (E2) by aromatase
What are the renal effects of pregnancy?
- Ureteric dilatation
- Increased water excretion
- Increased renal plasma flow
- Increased glomerular filtration rate (60%)
How are GnRH and LH released?
In a pulsatile way
What are the differences between FSH and LH?
They have the same alpha units but different beta units
- LH drives steroid production
- FSH works on the testes
What does the anterior pituitary produce?
- GH
- Prolactine
- ACTH
- FSH
- LH
- TSH
How is testosterone in the blood and in the testes?
MOSTLY BOUND TO SOMETHING
- Capillary (periphery) –> 99% bound to albumin (low affinity, high capacity), erythrocytes or SHBG (high affinity, low capacity),
- Seminiferous tubules –> 98% bound to androgen or binding proteins
Physiologicaly, how does an erection occur?
- “Erectogenic centers”: Medial Preoptic area and Hypothalamus paraventricular nucleus
- Lumbrosacral spinal cord
- Cavernous nerves (S2-4):
- Smooth muscle relaxation in the copora cavernosa: arteries/arterioles, penile trabeculae
- Nitric oxide is the single most important neurotransmitter to trigger erection
What are the components of delivery?
- Powers: Contractions
- Passenger: The fetus
- Passage: The pelvis
What is the crutial effects of progesterone in pregnancy?
- Implantation of blastocyte
- Protection from hypertension
