Ch.27: Reproductive System Part 2: Flashcards
____________, is the sequence of events in the seminiferous tubules of the testes that produce the male gametes: Sperm or spermatozoa
Spermatogenesis
Diploid chromosomal number is ___
46
The number of chromosomes in a human gamete is ___, referred to as the haploid chromosomal number
23
Gamete formation in both sexes involves _______, a unique kind of nuclear division that for the most part occurs only in the gonads
Meiosis
These cells called __________ ____, give rise to sperm, goes through In presence of Testosterone and Follicle stimulating hormone (FSH) released by the ant. Pituitary, each spermatogenic cell (2n= 46) undergo meiosis and forms four unidentical sperms ( n= 23
Spermatogenic cells
___________, during which it elongates, sheds its excess cytoplasmic baggage and forms a tail. HAS HEAD, MIDPIECE, and TAIL
spermiogenesis
The ______ of a sperm consist almost entirely of its flattened nucleus, which contains the compacted DNA
Head
A helmetlike _______ adheres to the top of the nucleus. It contains hydrolytic enzymes, which enable the sperm to penetrate and enter an egg.
Acrosome
The sperm __________ contains mitochondria spiraled tightly around the microtubules of the tail
Midpiece
The long tail is a typical _________ produced by one centriole near the nucleus.
flagellum
The __________ provides the metabolic energy needed for the whiplike movements of the tail that will propel the sperm along its way in the female reproductive tract.
Mitochondria
Important role of the Sertoli cells/ Supporting Cells/ Sustentacular cells:
- Blood-Testis Barrier (tight Junctions)
- provide nutrients & essential signals (live or die)
- move cells to the lumen
- secrete TESTICULAR FLUID (transport medium)
- Phagocytize faulty germ cells and excess cytoplasm
- produce chemical mediators (inhibin & Androgen-binding protein) which aid in regulating Spermatogenesis
Hormonal interactions between the hypothalamus, anterior pituitary gland, and gonads, a relationship called the ___________ _______ _______ (HPG) axis.
hypothalamic pituitary-gonadal axis
The hypothalamus releases _________ _________ hormone (GnRH), which reaches the anterior pituitary cells via the blood of the hypophyseal portal system.
gonadotropin- releasing hormone
GnRH controls the release of the two anterior pituitary gonadotropins: ________ _____ _______ and _______ ______
Follicle stimulating hormone (FSH) Lutenizing hormone (LH)
_____ stimulates spermatogenesis by stimulating the sustenocytes to release ANDROGEN-BINDING PROTEIN (ABP) ____ enhances testosterone’s stimulatory effects
FSH
_______ keeps the concentration of TESTOSTERONE in the vicinity of the spermatogenic cells high.
ABP
______ binds to the interstitial endocrine cells (LEYDIG CELLS) in the soft connective tissue surrounding the seminferous tubules, producing them to secrete testosterone.
LH
Rising __________ _______ serve as the final trigger for spermatogenesis
Testosterone level
__________, a protein hormone produced by the sustentocytes, serves as a “barometer” of the normalcy of spermatogenesis. When the sperm count is high more _______ is released, inhibiting anterior pituitary release of FSH and hypothalmic release of GnRH
Inhibin
Like all steroid hormones, testosterone is synthesized from __________ and exerts its effects by activating specific genes
Cholesterol
Male Secondary sex characteristics:
appearance of pubic, axillary, and facial hair deepening of the voice skin becomes oilier bones grow and increase in density high metabolic rate male libido
