T3: Spermatozoa/ Sperm Charcaterisitcs Flashcards
what parts make up the sperm
head and tail
what makes up the head in the sperm?
nucleus, acrosome, post nuclear cap
what makes up the tail in the sperm?
middle piece, principal piece, and terminal piece
what part has different characteristics for each species
the head, some tail variations
name the basic components of the sperm
acrosome and nucleus in the head, then the neck, mitochondrion(middle piece), plasma membrane, and tail
describe the nucleus of the head
-oval, flattened
-genetic material is nearly inert due to high degree of keratinization (disulfide cross-linking)
what happens in the nucleus of the head at fertilization
disulfide cross links are reduced by glutathione in cytoplasm of oocyte
what is the acrosome and what is the importance
-covers the anterior 2/3 of the nucleus
-membrane-bound lysosome that contains hydrolytic enzymes
what is the post nuclear cap
-membrane component posterior to the acrosome
describe the sperm head anatomy
at the top there is the apical ridge(enzymes are found here) following is the acrosome, then post nuclear cap, the nuclear ring/ equatorial ring separates the two regions, the plasma membrane surrounds the entire head and in the center is the nucleus
what are the two acrosomal enzymes
acrosin, hyaluronidase
where are the disulfide bonds
nucleus
what makes up the middle piece of the tail
-mitochondria: arranged in a helical structure
-laminated columns: flexibility for movement
-9 coarse fibers
-9 pairs of microtubules around 2 central filaments
what are the laminated columns, mitochondrial helix, and axoneme used for
flexibility, energy, and bending
what causes movement of the sperm
axoneme, motor proteins connecting the microtubules, allow the tail to bend and move the sperm through the repro tract
T/F the axoneme stretches through the entire tail
true
T/F the mitochondria are only contained in the middle piece
true
describe the components of the axoneme/ important motor proteins and their role
-Radial Spokes: that connect the microtubule inward (outer to center)
-Dynein arms: help with flagella movement(small stem like protrusions form the tubule) MOVEMENT
-Nexin: Anchoring protein, helps keep the outer tubes connected
describe the microtubule sliding in sperm tail
- Dynein arm elongated and attached (no ATP rigor)
- Dynein arm detaches and shortens(ATP release)
- Dynein arm tilts, elongates and attaches at lower site (ATP to ADP + energy/ re-extension/binding)
4.Dynein arm shortens and returns to horizontal “rigor” (elevation to sliding)
noted as walking up and down the pairs of microtubules
Describe the microtubule arrangement
2 central (singlet microtubules) to 9 microtubule doublets
- flagella can have portions of the tubule in different states and this is what gives it the shape
(9,9,2 arrangement of the axoneme)
what follows after the posterior head and is before the laminated columns (start of the middle piece)
capitulum
what is the juncture between the middle pieces and the principal piece
the annulus
what is the majority of the tail
principial piece
where is the fibrous helix found
in the principal piece, which is above the terminal piece
describe the subsections of the sperm
- Head: acrosome, neck/ capitulum
2.Tail
-Capitulum, midpiece, principal piece, and terminal piece
-the capitulum fits into the implantation socket
-annulus is separating the midpiece from the principal piece
where do microtubules end
in the terminal piece
what is the primary energy supply for sperm
glucose
describe the ATP utilization in sperm
- motility (60%)
-substrate cycling (40%): wasted
-maintenance of ionic gradients: very small amount
-no transcription and translation: none after condensation of nucleus and loss of residual body(cytoplasmic droplet)
what is sperm metabolism dependent on
-temperature (movement of flagella)
-ATP production increases as temperature increases
-ATP dependent processes are temp dependent
-motility increases with increasing temperature
-beat frequency increases with temp increase
how is sperm transported? what does each region do?
- vas efferentia: fluid flow/ cilia
- vas deferens: contractions
- corpus: contractions
- cauda: contractions
5.semiferous tubule: bulk fluid flow, contractions of myoid cells - rete testis: fluid flow, RT secretion
- Caput: contractions
what is the epididymal function
-change in fertility
-develop motility
-nuclear condensation
-cytoplasmic droplet
-increase disulfide crosslinking
-transport/ maturation mainly
what is the importance of a breeding soundness exam
ensures the male is ready to breed/ security blanket
what are the ejaculate characteristics of the species
bull-1 sec- single fraction
ram- 1 sec- single fraction
boar- 5-25 minutes- fractionated sperm free/ sperm rich coagulum
stallion-30-60 seconds- fractionated sperm free/ sperm rich mucus
human- 10-30 seconds- single fraction but coagulated
what are the things tested during a initial semen evaluation
color, volume, (visual) concentration, motility, viability, morphology
what is the typical semen color and volume
-color : white to cream color is good
yellow: urine is present
clear or thin: few sperm
-volume: weight 1ml to 1 gm
-concentration
hemocytometer: gold standard
spectrophotometer, photometer, fluorometer (measure DNA)
What are the components to a motility evaluation
-also a viability evaluation
-visual estimation (nearest 5% estimate)
-total motility: all moving sperm
-progressive motility: sperm moving in a straight line
-CASA: computer aided sperm analysis
-tracts individual sperm and computes a variety of stats
what is key to usefulness of data obtained
sample preparation
what does the color of the green florescent sperm in the viability assay mean? red?
red is dead
green is viable
what are the different sample preparations and methods for evaluation
-stain vs. no stain
-wet mount vs. dried or fixed
-magnification of observation
-computer systems require training samples
what are in scheme A of morphology classifications
primary: head abnormalities
secondary: tail abnormalities
what are in the scheme B of morphology classifications
Primary: head
secondary: tail
Tertiary: cytoplasmic droplets
what type of defects are the most concerning
proximal are the most concerning
what are the percent normal ranges for species
bull: 95
ram:95
boar: 90
stallion: 40-90
man: 30-70
