Sexual Reproduction #2 Flashcards
What purpose does the bulbourethral gland serve?
During sexual arousal, produce a clear slippery fluid that lubricates penis in preparation for intercourse.
Protects the sperm by neutralizing the acidity of residual urine in the urethra.
How does the erectile tissue assist during an erection?
Single corpus spongiosum along ventral side of penis: encloses spongy(penile)urethra.
Distal end enlarges and forms the glans penis
Two corpora cavernosa: Diverge like arms of a Y: covered with ischiocavernosus muscle.
What portion of the penis is removed during circumcision?
Lose tubular piece of muscosal skin known as foreskin
What hypothalamic and pituitary hormones regulate the testes?
As hypothalamus matures it produces Gonadotropin-realsing hormone(GnRH)
- GnRh stimulates anterior pituitary cells(gonadotropes to secrete
- FSH
- LH
What does FSH cause in the testes?
Stimulates sustentacular cells to secrete androgen-binding protein that binds testosterone, keeping it in the seminiferous tubule to stimulate speratogenesis and raising sperm count.
What does LH cause in the testes?
Stimulates interstitial cells to produce testosterone.
What physical changes occur during puberty?
Enlargement of secondary sexual organs:penis, testes, scrotum, ducts, glands.
Testosterone stimulates aburst of generalized body growth
Pubic hair, scent and subaceous glands develop
Stimulates sperm production and libido(sex drive)
How do testosterone and inhibin effect men in adulthood?
Testosterone sustains the male reproductive tract,sperm production and libido.
Inhibin-from sustentacular cell surpress FSH output from the pituitary, reducing sperm production without reducing LH and testosterone secretion.
What is the purpose of spermatogenesis?
Process of sperm production in seminiferous tubuler.
What major events will happen during spermatogenesis process?
- Remodeling of large germ cells into small, mobile sperm cells with flagella.
- Reduction of chromosome number by 1/2 in sperm cells
- Shuffling of genes so new combinations exist in the sperm that are different from parents
Spermatogonia
Lie along periphery of seminiferous tubules and divide my mitosis
Type A Spermatogonium
One daughter cell remains in tubule wall as stem cell
Type B Spermatogonium
One daughter cell migrates slightly away from wall and becomes sperm
Primary Spermatocyte
Diploid, then undergoes meiosis; each spermatocyte produces 4 spermatids
Blood Test Barrier
To prevent activation of the immune system of the male against the developing sperm
When do sperm become active?
20 to 30 minutes after ejaculation, sperm becomes active
Why is it important for seminal fluid to be sticky?
Promotes fertilization
Sticks to the inner wall of the vagina and cervix
Ensures that semen does not drain back into vagina
What do the prostatic and seminal vesticles contribute to the seminal fluid?
Prostate-Produces thin, milky white fluid
*Buffers vaginal acidity to activate sperm;clotting enzyme to stick
Seminal vesticles-Yellow fluid provide frutose and other sugars to mitochondria
What changes occur during spermiogenesis?
Condensation of nuclear material, acquire an acrosome (lysosome with enzymes), form a tail, develop a mitochondrial sheath around its tail, and extrude any unnecessary cytoplasm
What is the purpose of the Acrosome on the head of the sperm?
To help the sperm get through the eggs protective coat allow plasma membranes of the sperm and eggs to fuse
What is Acrosome?
Is a lysosome in the form of a thin cap covering the apical half of the nucleus. It contains enzymes that are later used to penetrate the egg if the sperm is successful.
Describe the stages of Meiosis I and II
Meiosis I
Prophase I, Metaphase I, Anaphase I, Telophase I
Meiosis II
Prophase II, Metaphase II, Anaphase II, Telophase II
Explain the outcome at the end of Meiosis II
Second division of meiosis. The cells must go through a second division in order to have the correct number of chromosomes. Meiosis is completed with four haploid daughter cells.
