What Makes A Normal Sperm Flashcards
what 3 components are human sperm made up of
- head
- midpiece
- tail
describe the head of the sperm with detail
- contains nucleus (genetic material)
- contains centrioles (inherited to zygote post-fertilisation)
- contains acrosome (contains enzymes to penetrate cumulus cells and zona pellucida)
describe the midpiece of the sperm with detail
contains sperm-specific mitochondria - produce energy for movement via oxidative phosphorylation
describe tail aka flagellum of sperm with detail
- contains axoneme - core structure
- axoneme functions as motors for motility through its 9+2 structure
- tail can generate energy thru glycolysis (breakdown glucose for energy)
what sperm characteristics are measured during a standard semen analysis
- sperm numbers (count / concentration)
- sperm motility (progressive, non-progressive, immotile)
- sperm morphology (head, mid-piece, tail)
what is the most widely used assessment of male fertility
semen analysis
what does sperm numbers reflect
- numbers of sperm produced by testes
- storage ability of sperm in post-testicular duct system (transport sperm from the testes to the outside of the body)
- efficacy of smooth muscle contractions in epididymis to actively transport sperm into ejaculate
count vs conc of sperm numbers
- count: total amount of sperm present in the ejaculate
- concentration: total numbers of sperm in 1ml of the ejaculate
3 key factors that influence sperm numbers
- size of testicles
- endocrine status
- medications, supplements, non-prescribe medications
describe relevance of sperm motility to fertility
- the amount of sperm moving forward is directly related to pregnancy rates
explain sperm motility assessment
proportion of sperm that have
- progressive motility (straight forward movement)
in total against
- non-progressive motility (tails moving but going nowhere or in circles)
- immotile (no tail movement)
if a sperm is immotile does it necessarily mean they are dead
no
what is how sperm look (sperm morphology) a predictor of
- fertilisation potential
what component/s of sperm is morphology evaluated on
- every component: head, mid-piece, tail
how many components have to have correct morphological appearance to be classified as normal sperm
- all components (head, mid-piece, tail)
what are 2 common things associated w poor sperm morphology
- defective spermatogenesis
- some epididymal pathologies
what are 3 things that poor sperm morphology are associated with an increase in
increased:
- sperm DNA fragmentation (presence of breaks or damage to DNA strands within sperm)
- chromosomal alterations
- aneuploidy (incorrect DNA copy number)
what is another category of interest that can be considered for sperm morphology & when is it an anomaly
- excess residual cytoplasm
- anomaly if more than 1/3 of normal sperm head size
describe ideal typical normal appearance of sperm head
- smooth
- oval in shape
- well-defined acrosomal region - 40-70% of head area
- not too large
- length-to-width ratio so not too round or elongated
- acrosome should contain no large vacuoles, only two or less 2 small vacuoles in head
- max 2 small vacuoles should not occupy more than 1/5th of sperm head
- post acrosomal region should not contain vacuoles
describe ideal typical normal appearance of sperm tail / flagellum
- uniform diameter along its length
- be thinner than midpiece
- about 10x head length
- may be looped back on itself as long as there no sharp angulation - indicate broken flagellum
- not bent
- no terminal droplet (residual cytoplasm)
describe ideal typical normal appearance of sperm mid-piece
- slender, regular
- about same length as sperm head
- should come out in centre of sperm head - alignment
- not too thick or too thin
- not sharply bent
- no asymmetrical insertion into head
- no angled insertion into head
- not non-inserted (can see top of mid-piece)
are the parameters (sperm count, sperm motility, sperm morphology) a direct measure of male fertility potential
no
what % of all infertility diagnoses are idiopathic (unknown cause)
15%
can men with infertility return a normal semen analysis
yes
