Lecture 13 Flashcards
Exocrine function of reproductive system
Production of gametes and secretions in semen: sperm, seminal vesicle fluid (60%), prostatic fluid (25%), and an alkaline secretion from the Bulbourethral (Cowper’s) glands that neutralizes the acidic male urethra and secretes mucous that lubricates the urethra and glans.
Endocrine function of reproductive system
Endocrine secretions are released in the blood and exocrine secretions are released externally. Testosterone secretion is an endocrine function
Internal Genitalia
Bulbourethral glands Ductus deferentes Epididymides Prostate Seminal vesicles Testes
External Genitalia
Penis
Scrotum
Male secondary characteristics
Mainly develop during puberty
•Distinguish males from females, and signal sexual maturity
•Pubic and axillary hair are not sexually dimorphic
•Larger skeleton, more skeletal muscle, laryngeal prominence, body hair, facial hair, and deeper voice are
•Important in intersexual selection –mate choice (mainly on the part of females)
How is sex determined in development
Y chromosome contains SRYgene (Sex-determining Region of Y)
- Codes for testis-determining factor
- Protein that alters gene expression and causes development of male reproductive structures
gonadal ridges
Gonads begin to develop at 6 weeks as gonadal ridges
•Near the primitive kidneys, called mesonephros
Nures cells in testes secrete testosterone which furthers the formation of male reproductive system
•Also, sustentacular cells secrete Müllerian-inhibiting factor, causing degeneration of the paramesonephric ducts
Mesonephric Ducts
Develops into male reproductive tract with testosterone
Paramesonephric Ducts
Develops into female reproductive tract
What chemical do the sustentacular(nurse) cells of the testes secrete early on in the development of a male embryo?
sustentacular cells secrete Müllerian-inhibiting factor, causing degeneration of the paramesonephric ducts
Why is testosterone and not estrogen used to determine if an embryo will develop male or female?
Because the levels of estrogen will be very high in the mother during pregnancy and would make all children female.
Genital tubercle develops into?
Male: glands and portion of shaft
Female: clitoris
Urogenital folds develop into?
Male: Urethra
Female: Labia Minora
Labioscrotal folds develop into?
Male: Scrotum
Female: Labia majora
Median septum
Separates testes and provides protection against infection or cancer from spreading between your two testes
Dartos Muscle
Wall of the scrotum. Helps with thermoregulation to keep testes at a slightly lower than the rest of the body
Tunica Vaginalis
Serous membrane that lines the scrotal sac and allows the testes to move around in the scrotum
What temperature does sperm production occur at?
35 C
Structures that provide thermoregulation of testes?
Ductus deferens - Portion of spermatic cord that helps keep temperature lower than core temp.
Cremaster muscles - derived from interal obliques and travel through spermatic cord. Contract or relax to allow for elevation or lowering of testes
Pampiniform plexus - Counter current heat exchange
Exocrine function of testes
produce spermatozoa
Endocrine function of testes
produce androgens, male sex hormones
Spermatic cords
attached at posterior of testes and pass through inguinal canals. Each contains a ductus (vas) deferens, blood vessels, nerves, and lymphatic vessels
What cells in the testes produce testosterone?
Interstitial cells that are located in the areolar connective tissue between the seminiferous tubules produce testosterone
What are the functions of the seminiferous tubules?
Location of sperm production
