Quiz 3 Lecture Notes Flashcards
3 parts of sperm structure
- head
- neck/connecting piece
- tail
3 parts of the sperm tail
- midpiece
- principal piece
- end piece
what is the most important part of the sperms structure and why?
- the nucleus
- the end goal of sperm is to transfer genetic material from the male to the oocyte and genetic information is stored in the nucleus
why are enzymes needed in the acrosome?
enzymes help to penetrate the oocyte
where is the mitochondria in the sperm and why is it located there?
- the midpiece
- energy is needed to move so mitochondria are located behind the nucleus to help it move forward
what is the purpose of the principal piece of the sperms tail?
makes it strong, able to make the contractions so the sperm can move
ODF purpose
- outer dense fiber
- maintains a rigid structure of the sperm
axonemes purpose
important for motility
axoneme
- skeletal components (formed by microtubules, dynein) that make motile proteins
- doublets are made that run through the tail, the back and forth of the doublets creates the back and forth movement of the tail to propel if forward
normal sperm motility
forward progressive motility
2 types of morphology abnormalities
- primary abnormality
- secondary abnormality
primary abnormalities
occurs during the generation of sperm (in the seminiferous tubules)
secondary abnormailites
occurs after leaving the seminiferous tubules
what type of abnormality: 2 heads
primary abnormality
what type of abnormality: coiled tail
secondary abnormality (cold shock)
what type of abnormality: head (no tail)
- primary or secondary
- if the head looks normal probably secondary
head abnormalities
- crater defect
- tapered heads
- ruffled acrosome
- knobbed acrosome
what type of abnormality: crater defect
primary abnormality
what type of abnormality: tapered heads
primary abnormality
what type of abnormality: ruffled acrosome
primary abnormality
what type of abnormality: knobbed acrosome
primary abnormality
tail abnormailites
- coiled tail
- double midpiece
- folded tail
- detached head
what type of abnormality: coiled tail
secondary abnormality
what type of abnormality: double midpiece
primary abnormality
what type of abnormality: folded tail
primary OR secondary
what type of abnormality: detached head
secondary (if the head looks normal)
spermatogenesis and location
- process to generate sperm
- location: seminiferous tubules
Sertoli cells
give the sperm cells nourishment so they can develop
Stages of Spermatogenesis
- spermatocytogenesis (mitosis)
- meiosis
- spermiogenesis
- spermiation
spermatocytogenesis (mitosis)
increase number of cells and formation of spermatocyte
meiosis
- 2N chromosome to 1N chromosome
- crossing over occurs
spermiogenesis
- formation of sperm
- change shape from round cell to sperm shape
spermiation
release of sperm from seminiferous tubules
in a male, how is fertility able to keep occurring?
the source of spermatogenesis (spermatogonia) can be renewed by mitosis. 2 divisions occur: one is the sperm and the other replaces spermatogonia
what is the source of spermatogenesis
spermatogonia
how long is a complete sperm cycle?
60-63 days, this is a continuous cycle so everyday cycles are ending and beginning again
spermiogenesis
process of metamorphosis, change the sperm from a round cell to the normal shape of sperm
spermiogenesis: the Golgi phase
- the Golgi moves towards the top of the cell making proacrosomic granules which will form the acrosome
- centrioles move towards the bottom of the cell
spermiogenesis: the cap phase
- acrosome is developed at the top
- proximal and distal centriole at the bottom (distal centromere begins forming the tail / axoneme)
spermiogenesis: the acrosomal phase
- acrosomic granule degenerates to leave just the formed acrosome
- the top of the cell is pushed down so the cytoplasm is moves towards the bottom of the cell (mitochondria pushed down)
spermiogenesis: the maturation phase
- normal sperm shape
- cytoplasmic droplet (formed from the excess cytoplasm) will move down the sperm cell and removed in the epididymis
spermiation
sperm to be released into the lumen
blood-testis barrier: function
prevent contact of germ cells from blood
how is the blood testis barrier formed?
- basement membrane
- sertoli cells
- wall of blood vessels
why do the tight junctions of Sertoli cells open and close?
so that the spermatogonia can move up the cells towards the lumen, moving higher concentration to lower concentration, the sperm shape begins to form
where is GnRH produced and its function?
hypothalamus, stimulates the anterior pituitary gland to produce LH and FSH
LH function is testis
LH will stimulate the leydig cells to produce testosterone
function of testosterone in the Sertoli cells
- converted to dihydrotestosterone by a 5 reductase (keeps a strong amount of testosterone in the Sertoli cells so spermatogenesis can occur)
- converted to estrogen by aromatase
How can testosterone regulate hormones?
testosterone produced from leydig cells can have a negative feedback on the hypothalamus to decrease the amount of GnRH produced
FSH function in testis
important for the spermatogenesis process
what control FSH through negative feedback?
inhibin
androgen binding protein
binds to DHT to keep a high concentration of testosterone in sertoli cells
fate of unejaculated sperm
- reabsorption
- disposal in urine
ejaculated sperm
semen = sperm + accessory fluid
functions of accessory fluid
- transport of sperm
- energy source
- buffer
why is important that accessory fluid is a buffer?
sperm is very sensitive and needs to be around osmotic pressure to survive the female reproductive tract
female reproductive tract function
- female gamete maturation
- sexual behavior
- fertilization
- pregnancy
what genes make the genital ridge into the biopotential gonad?
WT1 and SF1
2 main parts of the ovary
- cortex (outside)
- medulla (inside)
cortex function
follicle growth, CL forms
medulla function
blood vessels, lymphatic, etc.
ovary main function
to produce the oocyte
briefly, what are the stages of the oocyte production
it begins with primordial follicle, more granulosa cells form and eventually an oocyte is made, then a Graafian follicle is formed and oocyte is ready for ovulation, follicle is fluid filled (antrum) and producing estrogen to show signs of heat, ovulation occurs (rupture in the membrane and oocyte is released) and the CL forms, CL produces progesterone (if there is a pregnancy CL remains to keep the embryo alive, if there is no pregnancy PGF2a will regress the CL so a new follicle will form)
ovary produces 2 main hormones
- estrogen
- progesterone
what is different about the mare ovary anatomy?
- kidney shaped
- cortex is on the inside, so follicles form on the inside
- medulla is on the outside
- ovulation fossa (where ovulation occurs)
what is an explanation for the ovulation fossa in the mare?
twins can be fatal in horses so the narrow pathway of the ovulation fossa may limit the number of oocytes that can be ovulated at one time
theca cells
- internal and external
- the outermost membrane
theca cell: external
smooth muscle
theca cell: internal
secretes testosterone, the layer attached to the basement membrane
granulosa cells: mural
the outer layer, around the antrum (fluid)
granulosa cells: cumulus
the layer around the oocyte
antrum
fluid
cumulus oophorus
the stalk, cells that connect the oocyte with the wall so that the oocyte cannot hang in free fluid
zona pellucida
oocyte surrounded by glycoprotein layer for protection
corona radiata
establish connection with oocyte (first layer of granulosa cells)
