Physiology Flashcards
What does oestrogen do
Thickens uterine lining
What does progesterone do to the uterus
Makes the endometrium become glandular and secretory
Thickens the myometrium and reduces motility
Oestrogen changes to mucus?
Thin, alkaline, stringy cervical mucus
Progesterone changes to mucus
Thick acidic cervical mucus
What is the most abundant estrogen
Estradiol (E2)
What is the most abundant estrogen
Estradiol (E2)
How is oestrogen produced
Produced by ovaries in response to LH
What does fsh do
Acts upon the ovary
Stimulates develment of a primary follice
What does LH do
Acts upon the ovary
Stimulates production of estradiol (E2)
How does progesterone affect body temp
Causes increase of 0.2°C
What nerve fibres control the external anal sphincter
Somatic nerve fibres of the pudendal nerve (which can be consciously relaxed)
What nerve fibres innervate the internal anal sphincter
Parasympathetic nerve fibres from the pudendal nerve (which relax involuntarily)
What are the boundaries of the pelvic inlet
Lateral - iliopectinealline
Anterior - pubic crest
Posterior - anterior margin of the base of the sacrum and sacral promontory
What are the three types of naturally produced oestrogen
Estradiol, estrone, estriol
Where is estradiol produced?
Ovaries
What does the hypothalamus produce?
Gonadotropin releasing hormone
GnRH
What does the hypothalamus produce?
Gonadotropin releasing hormone
GnRH
On what does GnRH act?
Anterior Pituitary (producing LH and FSH)
What happens to ovarian follicle cells when FSH/LH act on them?
Differentiate into theca cells and granulosa cells
Dominant hormone in follicular phase?
Oestrogen
Dominant hormone in luteal phase?
Progesterone
What happens to the pituitary as oestrogen levels rise?
Oestrogen acts as an inhibitor and less FSH is produced
What does oestrogen do to the pituitary just prior to ovulation
Pituitary becomes more sensitive to GnRH, increasing sensitivity to oestrogen creating a surge of LH and FSH
How does progesterone act on the pituitary in the luteal phase?
Acts as an inhibitor and reduces production of LH
What happens when there is a reduction of LH from the pituitary in the luteal phase?
Reduction in production of progesterone (leading to menstruation)
In what cell is cholesterol turned into steroids hormones
Theca cells
What is cholesterol turned into in theca cells
Pregnenolone (by cholesterol desmolase)
Where is testosterone converted?
In granulosa cells by aromatase into 17b-estradiol
What is 17b-estradiol bound to in the blood?
Sex hormone binding globulin ((SHBG)
What transports progesterone in the blood?
Albumin and transcortin
Systemic effects of oestrogen
Cardiovascular - protective, keeps blood vessel walls flexible, reduces levels of LDL cholesterol
Skeletal - sustains bone density
Systemic effects of oestrogen
Cardiovascular - protective, keeps blood vessel walls flexible, reduces levels of LDL cholesterol
Skeletal - sustains bone density
Systemic effects of progesterone
Maintains bone strength
Increases skin elasticity
What does the placenta produce?
Estriol
Progesterone
What estrogen is being produced during menopause?
Estrone (E1) (by fat cells and adrenal glands)
What increases hepatic synthesis of transport proteins
Oestrogen
Receptors on theca cells
LH
Receptors on granulosa cells
FSH
What is produced within the theca cell
LH stimulates production of cholesterol -> progestogens -> androgens
(Granulosa cells can also do cholesterol ->progesterone)
What does the granulose cells do to androgens
Turns them into oestrogens
How long do platelets live for
9-10 days
What does LH do in men
Stimulates production of testosterone from leydig cells
How many days to grow a follicle
80 days
(65 + 5 + 10)
What produces AMH
Granulosa cells
What is AMH
Peptide growth factor
What is testosterone hydroxylated to
Dihydrotestosterone
What it testosterone aromatised to
Estradiol
Where is androstenedione produced
Ovaries and adrenals
Where is DHEA produced
Ovaries and adrenals
Where is prolactin secreted from
Lactotroph cells in anterior Pituitary
What synthesizes growth hormones
Somatotrophs in the anterior Pituitary
What controls production of growth hormone
Hypothalamic secretion of GHRH and somatostatin
First stage of female puberty
Thelarche (breast development)
What does oestrogen do in breast development
Duct growth
What does progesterone do in breast development
Growth of lobules and alveoli
When does DHEA production peak
Age 25
Definition of Delayed puberty?
Absence of secondary sexual development by 12 OR
Failure of menarche within 3 years of onset of secondary sexual characteristics
Where is oxytocin synthesized
Hypothalamus
What increases ESR
Large cells (macrocytosis), fewer cells, more proteins
LH subunit associated with PCOS
Beta subunit
Where is prolactin produced
Anterior Pituitary gland
What lymphocytes are the majority circulating lymphocytes?
T-cells
Where is oxytocin synthesized
Hypothalamus for release from posterior pituitary gland.
What produces inhibin in men
Sertoli cells
Where do sperm acquire the ability to become mobile
Epidymis
How are sperm formed
Primary spermatocytes are formed in the spermatogonium, which then divides into two secondary spermatocytes, which then becomes 4 spermatids
What do DNA polymerase enzymes do
Required for DNA replication and repair
MoA azithromycin
Prevents RNA dependant protein synthesis by binding to 50S ribosomal sub unit
What does factor Xa do
Converts prothrombin (Factor II) to thrombin
What does thrombin do
Converts soluble fibrinogen into solid fibrin clot
What are the factors in the PT pathway
Factor 7 then factor III
If factor 10 is affected, what coagulation pathway is affected
Both PT and PTT as factor X is common pathway
What receptors can be found on the bladder
Muscurinicn3 and beta 3
What receptor is on the male internal urthrethra
Alpha 1 receptor
What receptor is on the external urethral sphincter
Nicotinic receptor
Where is the micturation system located
Pons
What does the pelvic (parasympathetic) nerve act on on the bladder
M3 with acetylcholine causing contractions of the detrusor
What receptor does the pudendal nerve act on in micturition
Releases acetylcholine onto the nicotinic receptor at the external urethral sphincter
What does the hypogastric plexus (sympathetic) act on in the bladder
Releases noradrenaline onto beta 3 receptors causing relaxation of the detrusor
( And acts on alpha 1 receptor on internal sphincter causing contraction)
What binds platelets to Von Willebrand Factor
Glycoprotein 1b
What binds platelets together
Glycoprotein 2b/3a (and fibrinogen)
Majority circulating estrogen for someone on coc
Estrone
How much testosterone is bound to SHBG
2/3 of circulating testosterone
How much testosterone is bound to albumin
1/3 of circulating testosterone is weakly bound to albumin
How much testosterone is free circulation
2%
Rare causes of hot flushes?
Pheochromocytoma and carcinoid syndrome
Common causes of hot flushes
Menopause and hyperthyroid
Diagnosis of pheochromocytoma
Catecholamines
Diagnosis of carcinoid syndrome
24 hours urinary 5 hydroyindoleacetic acid
What does 5 alpha reductase do?
Convert testosterone into the more potent dihydrotestosterone
Gene mutation in 5 alpha reductase deficiency?
SRD5A2
Type of mutation for 5alpha reductase
Autosomal recessive, sex limited (male)
In theca cells, what converts cholesterol into pregnenalone
Cholesterol desmolase
In theca cells what converts pregnenolone to progesterone
3B-hydroxysteroid dehydrogenase
In theca cells, what happens to the pregnenalone that is not converted to progesterone
Converts to 17-hydroxypregnenolone then to dehydroepiandrosterone (DHEA)
In theca cells, what converts DHEA to androstenedione
3B-hydroxysteroid dehydrogenase
In granulosa cells, what converts androstenedione into testosterone
17B-hydroxysteroid dehydrogenase
What does testosterone convert to in granulosa cells
17B estradiol via aromatase
Where is oxytocin produced
Paraventricular nucleii of the hypothalmus
Where is oxytocin releases from
Herring bodies on the posterior pituitary
Where is prolactin produced
Lactotrophs in the anterior postuitary
What inhibits prolactin?
Dopamine
What does prolactin inhibit
GnRH (thus inhibiting lh and FSH)
What does prolactin do
Stimulate breast milk productiin
What does oxytocin do after birth
Cause alveolar duct myometrial cells to contract, pushing milk out
