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18. Reproduction- Male
N/A
98
Anatomy
Undergraduate 2
11/13/2012

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Cards

Term
Spermatogenesis is __________ sensitive in most mammals. What does this mean?
Definition
temperature; this means that is cannot occur at normal body temperatures
Term
At what temperature can spermatogenesis occur?
Definition
temperatures 3-5 degrees celsius less than body temperature
Term
What is the major factor that contributes to temperature regulation during spermatogenesis?
Definition
the scrotum
Term
What are the scrotal properties that facilitate thermoregulation?
Definition
  • location of the testis 
  • low insulation
  • sweat glands
  • tunica dartos
  • external cremaster muscle
  • thermoreceptors
Term
How does the location of the testis facilitate thermoregulation?
Definition
they are outside away from the body, allowing air circulation 
Term
How does low insulation of the scrotum facilitate thermoregulation?
Definition
ther is thin skin and low subcutaneous fat or hair
Term
How do seat glands on the scrotum facilitate thermoregulation?
Definition
there are many of them which allows evaporative cooling
Term
What is the tunica dartos?
Definition
it is smooth muscle which lines the scrotal wall
Term
How does the tunica dartos facilitate thermoregulation of the testis?
Definition
  • it can change the testis location: vary closeness to the body wall
  • change in scrotal surface area: vary thickness

 

Term
How does the external cremaster muscle facilitate thermoregulation of the testis?
Definition
it relaxes when hot and contracts when cold
Term
How do thermoreceptors facilitate thermoregulation of the testis?
Definition
nerves in the scrotum control the response to temperature of the testis  
Term
What so Leydig cells do?
Definition
they secrete masculizing testosterone during the breeding season
Term
What are seminiferous tubules?
Definition
highly coiled tubules where spermatogenesis takes place 
Term
What are sertoli cells?
Definition
a nurse cell of the testes which is part of the seminiferous tubules
Term
What are Leydig (interstitial) cells?
Definition
endocrine cells that produce testosterone
Term
5
Definition
Term
Starting in the testis, name the duct work going from inside the testis to outside?
Definition
seminiferous tubules, epididymus, ductus deferens
Term
_________ cells surround ________ cells.
Definition
Leydig, sertoli
Term
How does testosterone affect and organism before birth?
Definition
  • it masculinizes the reproductive tract and external genitalia
  • promotes descent of the testes into the scrotum of most mammals
Term
How does testosterone affect sex-specific tissues?
Definition
  • promotes growth and maturation of the reproductive system at puberty
  • essential for spermatogenesis 
  • maintains the reproductive tract throughout adulthood
Term
What are two other reproductive effects of testosterone?
Definition
  • develops the sex drive at puberty
  • controls gonadotropin hormone secretion
Term
How does testosterone affect secondary sex characteristics?
Definition
  • induces the male pattern of hair growth or feather growth
  • causes the voice to deepen because of thickening of the vocal cords
  • promotes muscle growth responsible for the male body configuration
Term
What are the nonreproductive actions of testosterone?
Definition
  • exerts a protein anabolic effect
  • promotes bone growth at puberty and then closure of the epiphyseal plates (stops growing)
  • induces aggressive behavior 
Term
What does spermatogenesis yield?
Definition
an abundance of highly specialized, mobile sperm
Term
What happens during spermatogenesis?
Definition
mitotic proliferation, meiosis, and packaging
Term
What is mitotic proliferation?
Definition
spermatogonia located in the outermost layer of the tubule continuously divide mitotically
Term
What is a gametogonia?
Definition
a germ cell that divides into gametocytes during gametogenesis
Term
What are male and female gametogonia called?
Definition
  • male: spermatogonia
  • female: oogonia
Term
What is gametogenesis?
Definition
a process by which haploid or diploid precursor cells undergo cell division and differentiation to form mature haploid gametes (spermatogenesis, oogenesis)
Term
What is a gamete?
Definition
a cell that fuses with another gamete during fertilization (conception) in organisms tha reproduce sexually
Term
What is an acrosome?
Definition
an organelle that develops over the anterior half of the sperm's head. It is a cap-like structure.
Term
Where are acrosome derived from?
Definition
the Golgi apparatus 
Term
When is acrosome formation completed?
Definition
during testicular maturation
Term
In Eutharian mammals, what does the acrosome contain and what do these products do?
Definition
  • they contain digestive enzymes (including hyaluronidase and acrosin)
  • these enzymes break down the outer membrane of the ovum called the zona pellucida, allowing the haploid nuclei in the sperm to join with the haploid nucleus found in the ova
Term
Starting with spermatogonium, name the stages of tranformation form spermatogonium to spermatozoa.
Definition
  • spermatogonium
  • spermatogonia
  • primary spermatocytes
  • secondary spermatocytes
  • spermatids
  • spermatozoa
Term
Are spermatogonium haploid or diploid?
Definition
diploid
Term
What forms of sperm are part of the stage of mitotic proliferation?
Definition
spermatogonium and spermatogonia
Term
Once there is a spermatogonium, what happens to it?
Definition
  • two daughter cells are produced (spermatogonia):
  • one daughter cell remains at the outer edge of the seminiferous tubule to maintain the germ cell line
  • the other daughter cell moves towrds the lumen to produce spermatozoa
Term
Are spermatogonia haploid or diploid?
Definition
diploid
Term
Once a spermatogonia is formed, what happens?
Definition
mitotic proliferation continues until primary spermatocytes are formed
Term
Are primary spermatocytes haploid or diploid?
Definition
diploid
Term
When does meiosis begin?
Definition
once primary spermatocytes have been formed
Term
What happens after primary spermatocytes are formed?
Definition
secondary spermatocytes are formed through meiosis
Term
Are secondary spermatocytes haploid or diploid?
Definition
haploid
Term
What is produced from secondary spermatocytes?
Definition
spermatids through meiosis
Term
When does the packaging phase begin?
Definition
once spermatids have been formed
Term
Are spermatids haploid or diploid?
Definition
haploid
Term
What is produced from spermatids?
Definition
spermatozoa
Term
Are spermatozoa haploid or diploid?
Definition
haploid
Term
What is located in the head of a sperm?
Definition
the nucleus and acrosome
Term
What is located in the midpiece of a sperm?
Definition
mitochondria
Term
What is located in the tail of a sperm?
Definition
microtubules
Term
Where is the centriole of a sperm located?
Definition
between the head and the midpiece
Term
Throughout their development, vertebrate sperm remain intimately associated with ________________.
Definition
sertoli cells
Term
Where do sperm develop?
Definition
within sertoli cells
Term
What is located between adjacent sertoli cells?
Definition
tight junctions
Term
What do the tight junctions between sertoli cells form?
Definition
a blood testis barrier 
Term
The blood testis barrier allows _____.
Definition
FSH
Term
What is the function of the blood testis barrier formed by the tight junctions between sertoli cells?
Definition
it preevents the formation of an anitbody for highly differentiated sperm
Term
What do sertoli cells provide for spermatozoa?
Definition
nutrients
Term
How are sertoli cells related to an immune response?
Definition
they carry out a phagocytic function to destroy defective germ cells
Term
Sertoli cells secrete _____________ and ____________.
Definition
seminiferous tubule fluid, androgen binding protein
Term
What is the function of seminiferous tubule fluid?
Definition
it flushes the released sperm from the tubule into the epididymus for storage
Term
What is the function of androgen binding protien?
Definition
it causes a high androgen concentration which is required for maintaining high testosterone concentration
Term
_____ and _______ from the ____________ control testsosterone secretion and spermatogenesis.
Definition
LH, FSH
Term
_____________ hormones activity increases at puberty.
Definition
gonadotropin releasing 
Term
18
Definition
Term
What is the function of the ducts in the reproductive tract?
Definition
they store and concentrate sperm and increase their fertility
Term
What are three main functions of the testis?
Definition
  • spermatogenesis
  • transport sperm out of the testis
  • produce testosterone
Term
How do the testis produce sperm?
Definition
sertoli cells are stimulated by FSH
Term
How do the testis transport sperm out of the testis?
Definition
  • myoid cells contract
  • smooth muscles in the testis capsule (tunica albuginea)
  • water absorption draws sperm towards the epididymus 
Term
How do the testis produce testosterone?
Definition
leydig cells are stimulated by LH
Term
What are the three main functions of the epididymus?
Definition
transport of sperm, concentration of sperm, and maturation of sperm
Term
What are the three factors that play into the role of the epididymus transporting sperm?
Definition
  • pressure of new sperm
  • regular contraction of smooth muscles
  • stimulated contractions of the cauda
Term
How does the pressure of new sperm aid in the transport of sperm through the epididymus?
Definition
sperm moving into the caput from the efferent ductules creates a pressure gradient
Term
How does regular contraction of smooth muscle aid movement of sperm through the epididymus?
Definition
the muscle surrounds the duct and causes peristaltic contractions every 6 seconds in the caput and corpus (independent of sexual activity)
Term
How does stimulated contractions of the cauda aid in transport of sperm through the epididymus?
Definition
increased contractions stimulated by sexual activity may reduce trasnport time in the cauda itself
Term
How does the epididymus concentrate sperm?
Definition
fluid is absorbed by the efferent ductules (concentration doesn't change much after the proximal caput)
Term
How does the epididymus function in the maturation of sperm?
Definition
  • sperm gain motility and fertility (this process is helped by androgen binding protein bound testosterone)
  • biochemical and physical changes to the sperm
  • controlled by rate of transport throught the epididymus and epididymal secretions: allows time for maturation
  • epidyidymal fluid changes: secretions are different in various segments of the epididymus: used to stimulate maturation and motility
  • capacitiation: removal of seminal plasma protein in the surface of sperm cells by secretion from the female reproductive tract anhances the sperm's capacity
Term
The _____________ contribute to the bulk of semen.
Definition
accessory sex glands
Term
What happens to the cells within the epididymus during breeding season?
Definition
they undergo hypertrophy and secrete seminal fluid
Term
What are the five main fucntions of seminal plasma?
Definition
  • transport media
  • culture media
  • stimulates sperm motility
  • retards sperm capacitation
  • stimulates sperm transport in the female
Term
In what way is seminal plasma a transport media?
Definition
it gives fluid volume to sperm and helps move the sperm through the urethra
Term
How does seminal plasma act as a culture media?
Definition
it provides the proper environment for sperm viability and  motility in the female reproductive tract
Term
How does seminal plasma stimulate sperm motility?
Definition
biochemical stimulation and it activates metabolic activity
Term
How does seminal plasma retard sperm capacitation?
Definition
it prevents the sperm from fertilizing immediately because we don't won't the sperm to activate until it is at the site of fertilization. Secretions in the cervix, uterus, and oviduct remove the coating on the sperm so they can fertilize 
Term
How does the seminal plasma stimulate sperm transport in the female?
Definition
uterine muscle contractions
Term
What are the four main functions of the male accessory sex glands?
Definition
  • supply fructose
  • secrete prostaglandins
  • provide more than half of semen volume
  • secretes fibrinogen
Term
What is the functions of the fructose that is supplied by male accessory sex glands?
Definition
it serves as the primary energy source for ejaculated sperm
Term
What is the function of the prostaglandins that are secreted by the male accessory sex glands?
Definition
they stimulate contraction of smooth muscle in both male and female reproductive organs to help trasnportation to the fertilization site 
Term
What is the purpose of accessory sex glands providing more than half of the semen volume?
Definition
it helps wash semen into the urethra and dilute sperm to help motility 
Term
What is the function of the fibrinogen that is secreted by the male accessory sex glands?
Definition
it keeps the semen where it was deposited where it's at; it forms a network to trap the semen
Term
With regards to the ejaculation characteristics of animals, ______________ and ___________ are inversely related.
Definition
volume, sperm concentration
Term
With regards to the ejaculation characteristics of animals, total _______ is related to total ________.
Definition
sperm, volume
Term
26
Definition
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