BIO 431 Exam Questions and
Answers 100% PASS
Testes Characterstics - CORRECT ANSWER--Male gonads, located externally
w/in scrotum
-Spermatic cord: Contains blood vessels (testicular artery/vein), lymphatic vessels,
nerve fibers going to/from testes, ductus deferens
>Life line between the body's exterior and interior
-Smooth + skeletal muscles
>Dartos (smooth) and Cremaster (skeletal)
>Pull testes toward body when contracted: Sexual arousal, decreased body
temperature
>Relax with increased body temperature
>* Temperature-sensitive sperm viability
,-Lobules: seminiferous tubules
>Stretch out to about 0.5 miles!
>Extensive surface area
Testes Function - CORRECT ANSWER--Produce sperm (spermatogenesis)
-Produce male sex hormones (androgens - testosterone)
Seminiferous Tubules - CORRECT ANSWER--Coiled tubes
-Contain spermatogenic cells: these develop into sperm
>400 million made per day
-Various stages of development within the tubules
-Sequence of development:
1. Spermatogonia
2. Primary spermatocyte
3. Secondary spermatocyte
4. Spermatids
5. Spermatozoa (sperm)
© 2026 Copyright. All Rights Reserved. This document is
protected by copyright law
,Cross-section of Seminiferous Tubule - CORRECT ANSWER--Least developed
cells will be on the outside aspect of the inner wall of the tubule
(spermatogonia/spermatogonium)
-Once the sperm has reached the final development stage, sperm will break off
from the wall of the seminiferous tubule and go into the lumen of the tubule
-Tails of the sperm can sometimes be seen on the inside of the cross-section of the
tubule
Spermatongenesis - CORRECT ANSWER-Order of least to most developed
stages of sperm
1. Spermatogonium (stem cell)
2. Primary spermatocyte
3. Secondary spermatocyte
4. Early spermatid
5. Late spermatid
5. Spermatozoa
3 Regions of the Sperm - CORRECT ANSWER-1. Head
-Nucleus (DNA): 23 chromosomes
-Acrosome (enzymes needed to penetrate egg): Hyaluronidase and acrosin
, 2. Midpiece
-Mitochondria: energy/ATP for movement
3. Tail
-Flagellum: propel sperm
Sustentocytes - CORRECT ANSWER--AKA Sertoli cells or Sustentacular cells
-Surrond developing spermatogenic cells
-Produce nutrients for developing sperm + fluid for outflow of sperm (testicular
fluid)
-Produce Androgen binding protein (ABP): Carrier molecule for hormone
testosterone
>Produced to make sure the steroid hormone testosterone is in a watery
environment
-Produce inhibin: Inhibits FSH (follicle-stimulating-hormone) release from anterior
pituitary
Blood Testis Barrier - CORRECT ANSWER--Tight junctions between
sustentocytes prevent it from coming into contact with blood
>Prevents immune response against sperm
>These cells do not have the same surface antigens
© 2026 Copyright. All Rights Reserved. This document is
protected by copyright law
Answers 100% PASS
Testes Characterstics - CORRECT ANSWER--Male gonads, located externally
w/in scrotum
-Spermatic cord: Contains blood vessels (testicular artery/vein), lymphatic vessels,
nerve fibers going to/from testes, ductus deferens
>Life line between the body's exterior and interior
-Smooth + skeletal muscles
>Dartos (smooth) and Cremaster (skeletal)
>Pull testes toward body when contracted: Sexual arousal, decreased body
temperature
>Relax with increased body temperature
>* Temperature-sensitive sperm viability
,-Lobules: seminiferous tubules
>Stretch out to about 0.5 miles!
>Extensive surface area
Testes Function - CORRECT ANSWER--Produce sperm (spermatogenesis)
-Produce male sex hormones (androgens - testosterone)
Seminiferous Tubules - CORRECT ANSWER--Coiled tubes
-Contain spermatogenic cells: these develop into sperm
>400 million made per day
-Various stages of development within the tubules
-Sequence of development:
1. Spermatogonia
2. Primary spermatocyte
3. Secondary spermatocyte
4. Spermatids
5. Spermatozoa (sperm)
© 2026 Copyright. All Rights Reserved. This document is
protected by copyright law
,Cross-section of Seminiferous Tubule - CORRECT ANSWER--Least developed
cells will be on the outside aspect of the inner wall of the tubule
(spermatogonia/spermatogonium)
-Once the sperm has reached the final development stage, sperm will break off
from the wall of the seminiferous tubule and go into the lumen of the tubule
-Tails of the sperm can sometimes be seen on the inside of the cross-section of the
tubule
Spermatongenesis - CORRECT ANSWER-Order of least to most developed
stages of sperm
1. Spermatogonium (stem cell)
2. Primary spermatocyte
3. Secondary spermatocyte
4. Early spermatid
5. Late spermatid
5. Spermatozoa
3 Regions of the Sperm - CORRECT ANSWER-1. Head
-Nucleus (DNA): 23 chromosomes
-Acrosome (enzymes needed to penetrate egg): Hyaluronidase and acrosin
, 2. Midpiece
-Mitochondria: energy/ATP for movement
3. Tail
-Flagellum: propel sperm
Sustentocytes - CORRECT ANSWER--AKA Sertoli cells or Sustentacular cells
-Surrond developing spermatogenic cells
-Produce nutrients for developing sperm + fluid for outflow of sperm (testicular
fluid)
-Produce Androgen binding protein (ABP): Carrier molecule for hormone
testosterone
>Produced to make sure the steroid hormone testosterone is in a watery
environment
-Produce inhibin: Inhibits FSH (follicle-stimulating-hormone) release from anterior
pituitary
Blood Testis Barrier - CORRECT ANSWER--Tight junctions between
sustentocytes prevent it from coming into contact with blood
>Prevents immune response against sperm
>These cells do not have the same surface antigens
© 2026 Copyright. All Rights Reserved. This document is
protected by copyright law
