Reproductive System Flashcards
Gonads (testes and ovaries) produce…
Gametes (sperm or eggs) and sex hormones
When is HPG axis established?
Puberty
Meiosis
-Basis of gamete production
-consists of 2 consecutive nuclear divisions w/o DNA replication in between
-reduces chromosomal # by 1/2 and introduces genetic variability.
-synapsis- fusion of chromosome pairs at the start of meiosis
-crossing over if homologous chromosomes (prophase 1)
-Is involved only in production of gametes:
-spermatozoa in males
-ova in females
-Human body cells contain ____________ chromosomes (23 Pairs) :
-meiosis divides chromosomes in half
-gametes contain 23 chromosomes
-They are haploid
Mitosis
-Is part of somatic division
-Produces 2 diploid daughter cells:
-both have identical pairs (23) of chromosomes
HPG
Hormonal interrelationship between the hypothalamus, anterior pituitary, and gonads that regulates the production of gametes and sex hormones
Reproductive system
-Gonads:
▪ organs that produce gametes and sex hormones
-Ducts:
▪ receive and transport gametes
-Accessory glands:
▪ secrete fluids into ducts
-Perineal structures:
▪ collectively known as external genitalia
What is the final outcome of meiosis?
Meiosis reduces the chromosomal count from 2n to n and introduces variability
What is the final outcome of meiosis?
Meiosis reduces the chromosomal count from 2n to n and introduces variability
Pathway of Spermatoza
■ Testis
■ Epididymis
■ Ductus deferens (vas deferens)
■ Ejaculatory duct
■ Urethra
Accessory Organs
■ Secrete fluids into ejaculatory ducts:
-seminal vesicles
-prostate gland
-bulbourethral glands
Give examples of homologous reproductive structures in males and females
Structures that share common origin during development and function
Testes- M ovaries- F
Gonads
Primary reproductive organ testes and ovaries
External male genitalia
■ Scrotum:
-encloses testes
■ Penis:
-erectile organ
-contains distal portion of urethra
Describe the HPG axis and its activation at puberty
hypothalamic-pituitary-gonadal axis, is a complex endocrine system that regulates reproductive development and function by involving the hypothalamus, pituitary gland, and gonads;
at puberty, the HPG axis becomes activated, leading to increased production of gonadotropin-releasing hormone (GnRH) from the hypothalamus, which then stimulates the pituitary gland to release follicle-stimulating hormone (FSH) and luteinizing hormone (LH), causing the gonads to produce sex hormones like estrogen and testosterone, marking the onset of puberty
Testis
■ egg-shaped
■ 5 cm long, 3 cm wide, 2.5 cm thick
■ Weighs 10–15 g
■ Hangs in scrotum
The Scrotum
■ Is a fleshy pouch
■ Suspended inferior to perineum
■ Anterior to anus
■ Posterior to penis
Testis
■ egg-shaped
■ 5 cm long, 3 cm wide, 2.5 cm thick
■ Weighs 10–15 g
■ Hangs in scrotum
The Scrotum
■ Is a fleshy pouch
■ Suspended inferior to perineum
■ Anterior to anus
■ Posterior to penis
Define meiosis
process in which a single (diploid) cell divides twice to produce four daughter cells which contain half the original amount of genetic information (haploid). - process that produces our sperm and egg cells, and the reproductive gametes of other organisms as well.
Compare and contrast meiosis to mitosis
Mitosis produces 2 identical diploid cells while meiosis produces 4 haploid cells with different genetic info in each cell
Organisms that under sexual reproduction meiosis
Eukaryotes- mitosis
The fetus: formation of testes
■ Testes form inside body cavity:
-are adjacent to kidneys
The Fetus: Gubernaculum Testis
■ Is a bundle of connective tissue
■ Extends from testis to pockets of peritoneum
■ Locks testes in position (near anterior abdominal wall) as fetus grows
Descent of the Testes
■ During seventh month:
-fetus grows rapidly
■ Circulating hormones:
■ cause gubernaculum testis to stop growing
■ testis are pulled into the scrotum accompanied by peritoneal cavity
Scrotum
-Contains the testes
-provides temp slightly lower than body temp as required to produce viable sperm
Cryptorchidism
■ One or both testes have failed to descend by birth
■ Corrective surgery is needed before puberty
■ If both testes are cryptorchid the individual will be sterile
Testis and lobules
Each testes is covered externally by a tunica albuginea that extends internally to divide the testis into many lobules.
Each lobule contains sperm-producing senuniferous tubules
Accessory structure of male reproductive system
-Accompany testis during descent
-Form body of spermatic cord:
-ductus deferens
-testicular blood vessels, nerves, and lymphatic vessels
-Extend between abdominopelvic cavity and testes
-Consists of layers of fascia and muscle
Pathway of Spermatic Cord
-Passes through inguinal canal
-Descends into scrotum
The Inguinal Canals
-Are passageways through abdominal musculature
-Form during development as testis descend into scrotum
Male inguinal hernias
■ Are protrusions of visceral tissues into inguinal canal
■ Spermatic cord (in closed inguinal canal):
-causes weak point in abdominal wall
Name the tubular structures in the testes that act as “sperm factories”
Seminiferous tubules
Carlos and Jennifer have been trying to start a family. Carlos spends his daily 2 hour commute working with his laptop on his lap. How might this affect his fertility?
Balancing his laptop on his lap for 2 hours a day might affect his fertility by increasing the temp inside scrotum. Increased testicular temp decrease fertility
Female inguinal canals
■ Are very small
■ Contain ilioinguinal nerves and round ligaments of the uterus
Muscle activity and the pampiniform venous plexus help to keep temp of testes at homeostatic levels. How do they do that?
When ambient temp is cold= associated muscles relax allowing testes to hang away from body wall. Pampiniform venous plexus absorbs heat from arterial 🩸, cooling the 🩸 before it enters the testes
The scrotum
■ Is divided into 2 chambers, or scrotal cavities
■ Each testis lies in a separate scrotal chamber
Raphe
■ Is a raised thickening in scrotal surface
■ Marks partition of 2 scrotal chambers
Describe the structure and function of the testes, and explain the importance of their location in the scrotum
The testes are the primary reproductive organ of the male, producing both sperm and testosterone.
The testes are divided into lobules with seminiferous tubules inside, where sperm are produced.
Interstitial cells are found in the connective tissue surrounding the seminiferous tubules and produce testosterone.
•The scrotum is a sac of skin and superficial fascia that hangs outside the abdominopelvic cavity at the root of the penis and houses the testes.
It provides an environment 3° below the core body temperature.
oIt responds to temperature changes.
Epididymis
-hugs the external surface of the testis
-serves as site for sperm maturation and storage
Dartos muscle
■ Is a layer of smooth muscle in dermis of scrotum
■ Causes characteristic wrinkling of scrotal surface
Ductus (bad) deferens
-extending from the epididymis to the ejaculatory duct, propels sperm into the urethra by peristalsis during ejaculation
-it’s terminus fuses w/ the duct of the seminal gland, forming the ejaculatory duct, which empties into the urethra w/in the prostate
Name the organs of the male duct system in order, from the epididymis to the body exterior. Which of these organs runs from the scrotum into the pelvic cavity.
-ductus deferens
-ejaculatory duct
-prostatic urethra
-intermediate part of urethra
-spongy urethra
What are the 2 functions of the stereocilia on the epididymal epithelium
Pass nutrients to the sperm and absorb excess testicular fluid
What are the 2 functions of the stereocilia on the epididymal epithelium
Pass nutrients to the sperm and absorb excess testicular fluid
Compare and contrast the roles of each part of the male reproductive duct system
Semineferous Tubules: production of sperm
Epididymis: sperm matures here
Ductus Deferens: carry sperm
Ejactulatory duct: carry sperm towards urethra:propels
Urethra: conveys urine and semen