Reproductive System Flashcards
What chromosomes are males?
XY
What chromosomes are females?
XX
What is the significance of the X chromosome being bigger than the Y?
Includes genes not present on Y
= responsible for sex characteristics
What are gonads?
Contain germ cells + produce gametes + hormones
What are the male gonads?
Testes —> sperm
What are the female gonads?
Ovaries —> egg
What is testosterone?
Potent androgen
Where is testosterone synthesised?
Within Leydig cells of testes
What does testosterone do?
Development + maintenance of male secondary sexual characteristics
What is male testosterone metabolised to?
Dihydrotestosterone + androsterone
What is female testosterone metabolised to?
Oestradiol + etiocholanolone
What are the actions of testosterone?
Stimulate enlargement of testes + male accessory organs
Stimulate development of mule secondary characteristics
What secondary characteristics does testosterone stimulate?
\+ body hair Enlarge larynx Thicken vocal cords Thicken skin Muscle growth Thicken + strengthen bones
Describe androgen receptors
Bind to receptor = heat shock proteins (hsp)
Complex migrates to nucleus
Bind to specific region of DNA that contain androgen response element (ARE)
What is the importance of androgen receptors?
Drives expression of genes that determine male phenotype
What happens to women with androgen insensitivity?
Sparse pubic hair + axillary hair
Describe testosterone level throughout life
Mini puberty at 6 months
Hormones unchanged until puberty
Maintained throughout life
Declined in old age
What are organs secreted by?
Hypothalamus
Anterior pituitary gland
Testes
What is significant about the ovaries?
Contain fixed no. of follicles
What happens during puberty in females?
Follicles mature
Describe brief process of ovulation
FSH —> release oestrogen —> release LH = ovulation
What happens when there is no fertilisation?
Progesterone level decrease = uterus wall shreds
How long is 1 cycle?
28 days
What are the ovarian steroid hormones?
Oestrogen Estrone (post-menopause) Estriol (pregnancy) Progesterone Androgens
What does oestrogen do?
Development + regulation of female reproductive system + secondary sex characteristics
What else does oestrogen do?
Provision of hormonal timing for ovulation
Develop tissues = implantation of blastocyte
Establishment of milieu required for pregnancy
At what age does menopause happen?
45-55 years
Why does menopause happen?
Ovaries fall to respond to FSH = no. of follicles decrease Weak oestrogen (E1)
Why does hot flushes happen in menopause?
Increase of LH + FSH
What is micturition?
Filling + emptying of bladder
Describe micturition
Parietal lobes + thalamus receive + coordinate detrusor afferent stimuli
Frontal lobes + basal ganglia provide modulation with inhibitory signals
What is the facilitatory of micturition?
Potine area, posterior hypothalamus + other cortical centres
What is the inhibitory of micturition?
In the mid
What does the sympathetic nerve do?
Transmits impulses from pain receptors to upper lumbar segment
= perception of pain sensation from urethra + bladder
What does the pelvic nerve do?
Transmits impulses from tension + pain receptors
= reflex micturition + sensation of bladder fullness
What does the pudendal nerve do?
Transmits impulses for sensation of …
Distension of urethra
Passage of urine through urethra
Maintains tonic contractions of skeletal muscle fibres of external sphincter
At volume is the 1st urge?
150-300ml
At volume is the sense of fullness?
300-400ml
At volume is the sense of discomfort?
400-600ml
At volume is the sense of pain?
600-700ml
At volume micturition cannot be suppressed?
700ml
