Physiology Flashcards
What does gonadotrophin releasing hormone (GnRH) release in females?
FSH (follicle stimulating hormone)
LH (Leutinising hormone)
What are the reproductive steroid hormones in females?
Estrogen(estradiol, estrone, estriol), Progesterone, Testosterone
Where are estrogen and progesterone released from in females?
Ovaries
When does estrogen exhibit positive feedback on the hypothalamus/anterior pituitary?
Day 12-14 on the cycle
When does estrogen exhibit negative feedback on the hypothalamus/anterior pituitary?
Most of the cycle
Which hormone is higher at the beginning of the ovarian cycle - progesterone/estrogen?
Estrogen
Which hormone is higher at the end of the ovarian cycle - progesterone/estrogen?
Progesterone
What does a follicle become upon expelling a secondary oocyte in the menstrual cycle (ovulation)?
Corpus Luteum
When does meiosis begin in a female?
Intra-uterine, before birth
When does meiosis 1 arrest in females?
After birth
When does meiosis 2 arrest in females?
At puberty (After meiosis 1 has released first polar body)
When does meiosis 2 resume in females?
At fertilisation (Releasing second polar body)
And what stage in the cell cycle is meiosis 1 arrested in females?
Prophase
What happens to fertility with age in females?
It decreases
What is the result to the uterine lining at the end of the menstrual cycle if pregnancy does not take place?
Menstruation
What is the function of germ cells in the male?
Production of sperm
What is the function of Sertoli cells in the male?
Support sperm producing cells
Production of inhibin (Inhibits FSH - Neg Feedback)
What is the function of Leydig cells in the male?
Production of Testosterone
What is the function of FSH in the male?
Spermatogenesis
What is the function of androgens in the male?
Secondary sex characteristics
Support sperm producing cells
When does meiosis occur in males?
Begins in puberty, continues throughout life
What factors can affect oogenesis/spermatogenesis from the site of hormonal control?
Problems with the hypothalamus;
Genetic (Klinefelters),
Tumours (Craniopharyngioma), Medications, Functional (stress, exercise, weight loss)
What factors can affect oogenesis/spermatogenesis from the site of production?
Problems at site of production; Genetic, Cancer treatment induced, Surgery (Vasectomy), Trauma, Infections
Which hormone is produced by the corpus luteum towards the end of the uterine cycle?
Progesterone
What are the different stages in the ovarian cycle?
Primordial follicle > Primary follicle > Theca Cells > Mature (Graffian) Follicle > Ovulation > Young corpus luteum > Corpus luteum > Corpus albicans
What is the role of FSH from anterior pituitary in females?
Stimulate follicle recruitment and development
What is the role of LH from anterior pituitary in females?
Maintain dominant follicle, induce follicular maturation and ovulation, stimulate CL function
What is the role of oestradiol from granulosa cells in females?
- Supports secondary sexual characteristics
- Negative feedback of LH and GnRH
- EXCEPT for late follicular phase - positive control of LH surge
- Stimulates proliferative endometrium
- negative control of FSH
What is the role of progesterone from CL in females?
- Maintenance of secretory endometrium
- Negative feedback of HPO
Which hormone stimulates ovulation in females?
LH (leutinising hormone) - LH surge!
Which hormone helps to repair endometrium lining in females?
Estrogen
List potential targets for oestrogens in females?
Uterus Mammary gland Bone maturation + turnover CNS Anterior pituitary Fat distribution
What are some systemic effects of oestrogens in females?
Protein, CHO, Lipid metabolism
Water + Electrolyte balance
Blood clotting
What structure is responsible for production of the majority of seminal fluid in males?
Seminal vesicle
List potential targets for testosterone in males?
Male sex organs (Growth, sprematogenesis, prostate growth + function) Liver (Serum protein synth) Skin (Hair, balding, sebum) Brain (Libido, mood) Muscle (Strength, volume) Kidney (EPO) Bone marrow (Stem cells stimulation) Bone (Accelerated closure of epiphyses)
What structure releases FSH and LH?
Pituitary gland
What are the two phases of the ovarian cycle?
Follicular Phase
Luteal Phase
What is the function of LH in males?
Triggers Leydig/Interstital cells to produce testosterone
What happens to progesterone levels after fertilisation?
Continue to rise
What does progesterone do to the endometrium?
- Progesterone stops uterine lining from shedding - maintains uterine thickness
- Encourages decidua formation
What is the name given to cells on the outer layer of the fertilised egg?
Trophoblasts
What structures do trophoblasts cells go on to form?
Placenta and membranes
What hormone is produced by trophoblast cells?
B-hCG (Beta - human Chorionic Gonadotrophin)
What is the target of B-hCG?
Corpus luteum in ovary
What is the function of B-hCG?
Stimulates corpus luteum to produce progestogen. Stops uterine lining from chedding.
What structures invade mother’s blood vessels to provide the chorion with blood?
Trophoblast cells (cover Chorionic villi)
What do the methylated maternal genes in ovaries promote?
Early baby growth
What do the methylated paternal genes in ovaries promote?
Early placenta growth
Does glucose cross the placenta?
Yes
What may diabetes in pregnancy do to size of the baby?
Hyperinsulinaemia and hyperglycaemia - may lead to intrauterine death and massive growth
What is considered mild chronic hypertension in a patient <20 weeks pregnant?
Diastolic BP - 90-99
Systolic BP - 140-49
Why do insulin requirements of the mother increase during pregnancy?
Human placental lactogen, progesterone, HCG, cortisol all have anti-insulin action
Why is pregnancy a hypercoaguable state?
- Increase in fibrinogen factor 8, vW factor, platelets
- Decrease in natural anticoagulants - antithrombin III
- Increase in fibrinolysis