week 2

Question 1

Describe the process of spermatogenesis

Answer 1

seminiferous tubules make sperm. testes are 90% these.

sertoli cells secrete growth factors that ‘nurse’ sperm in an adluminal compartment.

tightly contained compartment provides right environment.

leydig cells outside of the tube lumen

Question 2

Detail the process of steroid production in the male including its endocrinological control

Answer 2

Question 3

Describe the physiological processes of erection and ejaculation

Answer 3

Question 4

Identify the components of semen analysis

Answer 4

initial precum to neutralise urine acidic levels in the urethra + lubricate. made by bulbo urethral glands

seminal fluid compromises 50-70% of ejaculate. proteins electrolites, mucus, vit C.

prostate- milky white fluid 30% of vol. 1% protein content. inc proteolytic enzymes. high zinc (antibac)

liequefaction of sperm is important to help sperm move when inside, once held in place by the more viscous initial texture.

Question 5

differences between spermatagonia

Answer 5

dark (A) spermatagonia mitotically divide producing primary spermatocites.

a proportion become B and enter meiosis. - become primary spermatocites.

Question 6

what do sister chromatids do

Answer 6

primary spermatocytes duplicate to prod sister chromatids

they exchange genetic material at this point to produce slight genetic differences.

Question 7

how long does it take to make a sperms

Answer 7

74 days to make it.

new cycle every 16 days.

Question 8

what is oligospermia
aspermia
motility

Answer 8

less than 15 mill per ml

no sperm

amount of sperm swimming. (prog mot is number getting somewhere)

Question 9

what is the structure of a sperm

Answer 9

Question 10

Describe the process of sperm capacitation and acrosome reaction

Answer 10

capacitation- need to undergo changes after ejaculation to be able to fertilise an egg. takes 14-24 hours. generally re-arrangement of molecules. (removal of cholesterol and Ca entry CatSper channels)

on inner acrosome- receptors adhere to the egg after zona has been enzymatically degraded (e.g acrosane)

also specific adhesion mollecules- species specific

Question 11

Describe the role of the corpus luteum

Answer 11

prod more progesterone than oestrogen.
14 day lifespan.- LH could save but is suppressed by CL own progesterone production.

saved in pregnancy by hCG which bind to LH receptors (hCG prod by embryo)

Question 12

Describe the process of fertilisation

Answer 12

sperm binds to zona pelucidda

released enzymes (acrosane)

cortical granules release contents- cutting away receptors- cross lining making it rigid..

once one sperm entered door is ‘locked’

Question 13

Appreciate the stages of early embryo development- describe them including polar body ejection,

Answer 13

syngamy-
after meiosis 1 oocyte had 23 chromasones but two copies of each arranged as sisters

entry of sperm causes an inc in ca2 via phospholipase zeta from sperm

ca causes completion of meiosis 2 expelling 2nd polar body & cortical reaction

The sperm nuclear
membrane breaks down,
the chromatin
decondenses and
chromosomes separate

2nd half is in the picture.

Question 14

what does visualisation of a polar body mean

Answer 14

completeness of meiosis 1
division
been exposed to LH

if can see two then has completed meiosis 2

Question 15

summarise fertilisation.

Answer 15

Question 16

first 5 days of development what happens

Answer 16

Question 17

Outline the pathways in the synthesis of testosterone, dihydrotestosterone and oestrogen

Answer 17

control via hypothalamic pituitary axis.

test synth by leydig cells (LH binds, inc intake of cholesterol +transcription of genes)

Question 18

List the effects of testosterone and DHT in the bodies of males and females

Answer 18

bind to nuclear receptors.
taken into nucleus
promote transcription. Nuc receptors are specific for each hormone.

can also switch off some genes, including tissue and cell cycle specific genes.

secondary sexual charicteristics.

Question 19

Describe the bodily effects of anabolic steroid abuse

Answer 19

disrupts/ switches off hpa axis. can switch it off and then shrink in size.

can also cause HTN (calcium, water and sodium retaining properties)

liver cancer
baldness
premature epipheses closure
gynocomastia

Question 20

Explain the mechanism of action of androgenic and anti-androgenic drugs in common medical conditions

Answer 20

prostate hyperplasia- block androgen receptors can block the cancer.

in prostate test -> DHT. 5Areductase inhibitors can present high expusure.

switch off androgen receptor signalling- switch off growth.

abiraterone- stops test being synth entirely.
zitega stops cholesterol synth.

stop hpa - antagonistic or superagnoists to the hypothalamus hormones.

competitive inhibitors of androgen receptors- bicalutamide.

Question 21

Describe the modes of action of common methods of contraception

Answer 21

barrier
cycle awareness

hormonal contraception. - inhibition of ovulation by feedback on the HPO axis.

Question 22

List the risks and benefits of common methods of contraception

Answer 22

often need to be taught
often fail when done in normal use.
may require ongoing use rather than one off intervention.

pill is rapidly reversible, helps with some cancers and menstrual disorders. - incs DVT risk. changes in mood libido, weight gain.

coil- lasts 5 years, useful in endometriosis, menorrhagia, dysmennorhoea. May be expelled, may have ectopics, may perforate uterus.

many put the woman in control
some prevent against STI.

Question 23

Demonstrate an awareness of the relative efficacy of common methods of contraception

Answer 23