Therio - Sperm Production

Front 1

Spermatozoa
-produced where

Back 1

-seminiferous tubules of the testes

Front 2

Spermatogenesis
-involves

Back 2

-proliferation of stem cells
-meiotic division of stem cells
-differentiation from a nucleated round cell to a more specialized tadpole shape

Front 3

Spermatogenesis
-importance of meiosis

Back 3

-homologous chromosomes form pairs and exchange DNA --> every chromosome in a sperm cell has DNA from sire and Dam

Front 4

Sperm
-levels of development

Back 4

Spermatogonium --> (mitosis) additional spermatogonia
-primary spermatocyte
-(1st mieotic division) secondary spermatocye
-(2nd mieotic division) spermatids
-sperm

Front 5

Sperm
-reduction divisions in formation begin when

Back 5

-puberty

Front 6

Onset of meiosis is controlled by:

Back 6

-mieosis inducing substance (MIS)
-meiosis preventing substance (MPS)

*secreted by testicular tissue

Front 7

Sperm
-plasma membrane function

Back 7

-micro-domains of signaling molecules

Front 8

Sperm
-head importance

Back 8

-contains chromatin
-posterior portion attach to the egg
-acrosome

Front 9

Sperm
-acrosome importance

Back 9

-membrane enclosed sac of enzymes important for penetrating the Zona pellucida of the oocyte

Front 10

Sperm
-mitochondria importance

Back 10

-convert glucose to ATP
-located in midpiece

Front 11

Sperm
-tail importance

Back 11

-necessary to swim to oocyte, penetrate zona pellucida, fertilize egg

Front 12

Sperm
-tail parts

Back 12

-midpiece
-principle piece
-end piece

Front 13

Testicle
-main component

Back 13

Tightly packed seminiferous tubules
-90% (bulls, rams, rats)
-60% (boars, stallions)

Front 14

Sertoli cell
-function

Back 14

-support maturation of spermatogonia

Front 15

Testicle
-interstitial tissue components

Back 15

-blood vessels
-nerves
-leydig cells

Front 16

Leydig cells
-main function

Back 16

-synthesize steroid hormones (testosterone)

Front 17

Sperm
-proximal droplet is a representation of?

Back 17

-old cytoplasm

Front 18

Sperm
-travel

Back 18

-seminiferous tubules
--rete testis
---efferent ducts
----epididymis
-----vas deferens

Front 19

Rete testis
-define

Back 19

-collection from seminiferous tubules
-located in center of testicle

Front 20

Efferent ducts
-define

Back 20

-3-20 ducts leading from rete testis to epididymis

Front 21

Epididymis
-define

Back 21

-single long tubule that is metabolically active
-tail stores sperm

Front 22

Vas deferens
-function

Back 22

-connects epididymis to urethra
-has thick muscular wall for ejaculation

Front 23

Spermatozoa
-movement when taken from rete testis

Back 23

-weak vibrating movement of tail

Front 24

Spermatozoa
-movement when taken from head of epidiymis

Back 24

-slow circular motion

Front 25

Spermatozoa
-movement when taken from the tail of the epididymis

Back 25

-vigorous uni-directional progressive motility with longitudinal rotation of the head

Front 26

Physiologic changes in spermatozoa as they traverse the tubular tract

Back 26

-gain ability for progressive motility
-acrosome matures
-plasma membrane stiffens in some areas and increases flexibility in others

Front 27

The ability of the epidiymis to maintain sperm viability and allow maturation is dependent on?

Back 27

Androgen steroids
-testosterone

Front 28

Blood-Testis Barrier
-define

Back 28

-tight junction between sertoli cells which divide tubules into 2 compartments

Front 29

Blood-Testis Barrier
-compartments

Back 29

-Basal Compartment
-Adluminal compartment

Front 30

Blood-Testis Barrier
-Basal compartment function

Back 30

-contains spermatogonium and preleptotene spermatocytes

Front 31

Blood-Testis Barrier
-Adluminal compartment function

Back 31

-communication with lumen of tubule and contains more advanced stages

Front 32

Blood-Testis Barrier
-permeability

Back 32

-complete exclusion of antibody
-free transfer of androgen-binding protein and inhibin

Front 33

Blood-Testis Barrier
-function

Back 33

Keeps haploid cells from initiating an immune reaction
-prevents protein hormones and antibodies from coming into contact with germ cells from spermatocytes onward
-prevents haploid spermatogenic cell proteins from causing an immune reaction

Front 34

Animal scrotum types:
-without scrotum
-intra-abdominal testes
-non-pendulous scrotum
-pendulous scrotum

Back 34

Without scrotum
-reptiles, birds

Intra-abdominal testes
-elephants, dolphins, whales, armadillos, ...

Non-pendulous scrotum
-pigs, horses, cats

Pendulous scrotum
-cattle, sheep, primates

Front 35

Testicle temperature within scortum compared to body temp

Back 35

4-7C cooler

Front 36

Rise in testicle temperature
-effect

Back 36

-abnormal spermatogenesis ---> infertility

Front 37

Tunica dartos
-define

Back 37

-smooth muscle located just below the skin surface of the scrotum

Front 38

Tunica dartos
-function

Back 38

Helps to regulate testicular temperature
-Contraction: reduces surface area available for heat loss
-Relaxation: increases surface area available for heat loss

Front 39

Cremaster muscle
-function

Back 39

Retracts the testicles
-conservation of heat on a cold day
-fight or flight response to move the testicles out of the way

Front 40

Pampiniform plexus
-define

Back 40

-coiling testicular artery and vein that creates a counter-current exchange to cool blood in the artery supplying the testicles
-decreases temp of arriving blood by 5C

Front 41

Pampiniform plexus
-effect of fat deposition in the area

Back 41

-more insulation ---> decreased heat loss

Front 42

Puberty
-onset controlled by

Back 42

-maturing of the hypothalamic-pituitary-gonadal (leydig & sertoli cell) axis

Front 43

Puberty in the Bull
-definition

Back 43

-ejaculate has a minimum of 50 million total sperm with 10% progressive motility

*not considered sexually mature though

Front 44

Why do sperm cells near puberty have many of the same defects as sperm cells from degenerating testicles?

Back 44

-low testosterone

Front 45

Disturbances of spermatogenesis are manifested by:

Back 45

-reduced sperm production
-increased sperm abnormalities

*Usually # of sperm not counted. Typically if sperm are abnormal it is thought that there is probably an abnormal amount

Front 46

Testicular degeneration
-types

Back 46

-Temporary followed by regeneration
or
-Permanent followed by fibrosis

Front 47

Describe

Back 47

Sertoli cells in seminiferous tubules

-only thing that should be found in lumen is tadpole-like sperm
-palpate many times as soft

Front 48

One way to know there is a problem with the testicles

Back 48

-ability to make a dent in them with slight pressure

Front 49

Describe

Back 49

-seminiferous tubule breakdown with fibrosis

Front 50

Pathogenesis of abnormal sperm production

Back 50

Anything that drops testosterone levels
-Stress (pain, hunger, cold)
-Heat (obesity, scrotal abnormality, climate, fever)
-Season (photoperiod, nutrition, temp)
-Heredity (sperm defects, testis size)
-Puberty (resembles disturbed spermatogenesis)
-Toxicity (plant, bacterial, environmental)
-Nutritional (protein, Vit A, Se-deficiency)

Front 51

How to know if a defect in sperm production may be hereditary

Back 51

-if hereditary all sperm from different areas of the tract will likely have the same defect
-if non-hereditary sperm defect will correspond to where sperm were in development along the tract when the insult occured

Front 52

How does stress effect sperm production.maturation?

Back 52

-suppresses LH release which is necessary for testosterone production
--testosterone is needed for spermatogenesis and epididymal function

*LH is needed to convert cholesterol to testosterone in the leydig cells

Front 53

Subfertility due to increased body temp
-can be caused by

Back 53

-excess fat in the scrotum
-high temperature & high humidity
-fever

Front 54

Effect of heat on spermatogenesis

Back 54

-testes normally function on the bring of hypoxia
--increase in temp causes a decrease in the metabolic rate
---no corresponding increase in blood flow to the increase in metabolism
----tissue becomes hypoxic

Front 55

Effect of an increase in temperature (fever) on fertility

Back 55

-developing sperm are killed but the sperm already formed are OK for 1-2 wks
-poor quality sperm for at least 1 month
-gradual improvement until normal sperm in 3 months

Front 56

Sperm defects correlated to timing of ejaculation post-insult

Back 56

Front 57

Defects post insult
-8 days post

Back 57

-distal midpiece reflex
-proximal droplets

*epididymis

Front 58

Defects post insult
-12-15 days

Back 58

-decapitated sperm
-mitochondrial helix

Front 59

Defects post insult
-15-20 days

Back 59

-diadem defect

Front 60

Defects post insult
-18-24 days

Back 60

-vacuoles
-coiled principle piece
-pyriform plexus

Front 61

Defect post insult
-30 days

Back 61

-acrosome damage

Front 62

Sperm
-length of time to mature in seminiferous tubules

Back 62

-39 days

Front 63

Sperm
-length of time to traverse epididymis

Back 63

-7-16 days