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Physiology Chptr 20
Sexual Reproduction
| Question | Answer |
|---|---|
| Early embryonic gonads can become either _______ or _______. | Testes/ovaries |
| What chromosome induces the formation of the testes? | Y |
| What hormone from the testes induces formation of the male sex organs and absence forms the female sex organs? | Testosterone |
| What are formed in gonads by meiosis? | Gametes |
| Each gamete has a ______ number of chromosomes (23) | Haploid |
| Fusion of sperm and egg during ______ results in a _______ ______ with 43 chromosomes. | Fertilizatio/dipoid zygote |
| Each zygote inherits __ chromosomes from mother and __ from father producing __ pairs of ____________ ___________. | 23/23/23/homologous chromosomes |
| How many autosomal chromosomes are there? | 22 |
| the 23rd pair of chromosomes are _____ chromosomes. | Sex |
| There are more genetic diseases causes by the _____linked gene. | X |
| Only 1 of 2 Xs in the females becomes active in meiosis the other forms a clump of inactive heterochromatic called what? | Barr body |
| What is used as a test for chromosomal sex? | Barr body |
| What occurs in a gamete or zygote and causes differential expression of alleles? | Genomic imprinting |
| In genomic imprinting each gene is represented either by the same or an alternative allele and both are usually expresses. In approximatelly ____ genes either the maternal or paternal allele is ___________. | 80/silenced |
| Silencing of an allele is accomplished by _________ changes to the chromatin, such as by methylation of cytosine bases in DNA. | Epigenetic |
| The 1st 40 days after conception, ganads of males and females are __________. | Similar |
| Gonads have the potential to become testes or ovaries until what causes a conversion to testes which is produced by what gene? | Testis-determining factor (TDF)/Sex-determining region of Y (SRY gene) |
| __________ tubules appear within 43-50 days following conception as opposed to _________ ________ that don't appear until day 105. | Seminiferous/ovarian follicle |
| What masculinizes the embryonic structures? | Leydig cells |
| In developing testes what cells begin secreting testosterone at 8 weeks of development and peak at 12-14 weeks and then decline to very low levels until puberty? | Leydig cells |
| When do the testes descend into the scrotum? | Shortly before birth |
| Spermatogenesis does not occur in males with undescended testes because it requires a 3 degrees C lower temperature than the body and is a condition called what? | Cryptorchidism |
| Seminiferous tubules (STs) contain germinal cells which will produce _______ and nongerminal cells called __________ which appear at day 42. | Sperm/Sertoli |
| At ~day 65, during the formation of testes, _______ cells (that produce testosterone) appear in cluster around the seminiferous tubules. | Leydig |
| What develops in the absence of TDF? | Ovaries |
| What ducts are male accessory sex organs derived from? | Wolffian |
| What are the 4 wolffian ducts? | Epididymis, vas deferens, seminal vesicles, and ejaculatory duct |
| What ducts are the female accessory organs derived from? | Mullerian |
| What are the 2 mullerian ducts | Uterus and fallopian tubes |
| Testosterone from _____ cells causes ______ ducts to give rise to male accessory organs. | Leydig/Wolffian |
| At ~day 60, _______ cells secrete Mullerian inhibiting factor (MIF) which causes Mullerian ducts to regress. | Sertoli |
| What secretions masculinize the external genitalia of men to form what 4 things? | Testis/penis/urethra/prostate/scrotum |
| In the absence of testosterone _______ forms instead of a penis and the _____ forms instead of the scrotum. | Clitoris/labia |
| What disorder occurs when individuals have both ovary and testis tissue? | Hermaphroditism |
| What disorder occurs when the testes or ovaries are present (not both) but the accessory organs and external genitalia are incompletely developed or inappropriate for their chromosomal sex? | Pseudohermaphrodites |
| The most common cause of female pseudohemaphroditism is what? | Congenital adrenal hyperplasia |
| One cause of pseudohermaphroditism in males is caused by ______ ______ _____ in which the testes are normal but there are no receptors for testosterone. | Testicular feminizing syndrome |
| What embryonic sexual development disorder causes a male to develop a very female appearance and is also infertile | Testicular feminizing syndrome |
| In which trimester is there a lot of testosterone produced to masculinize the fetus? | 1st |
| Ovaries don't produce much _____ ______ until puberty and both testes and ovaries remain inactive after birth until ________. | Sex steroid/puberty |
| What part of the brain controls the release of LH and FSH from the anterior pituitary with GnRH. | Hypothalamus |
| What 2 hormones stimulate the production of sperm and eggs, and gonadal sex steroids and maintains the size of the gonads? | LH and FSH |
| Sex steroids provide what type of feedback on hypothalamus and the Ant. Pit.? | Negative |
| What hormone does the gonads secrete which negatively feeds back on FSH secretion? | Inhibin |
| At puberty the hypothalamus increases the secretion of what hormone which stimulates the increase of what 2 hormones? | GnRH/LH/FSH |
| When is the secretion of FSH and LH low? | Between the 6th month of life until puberty |
| What 2 hormones stimulates sex steroid seretion? | LH and FSH |
| LH and FSH stimulates the secretion of sex steroids wich drives changes in __________ ______ characteristics and ____________. | Secondary sex/Menarche |
| Growth of pubic and axillary hair is due to the secretion of what? | Androgen |
| The growth of pubic and axillary hair is due to androgen secretion from what endocrine gland? | Adrenal cortex |
| What is the 1st menstral flow called? | Menarche |
| The age of puberty in girls depends on what 2 factors? | % of body fat and physical activity |
| At the beginning of female puberty a high level of ____ stimulates growth? | E |
| Melatonin inhibits the secreation of what hormone? | Gonadotropin |
| What endocrine gland appears to play a role in seasonal reproduction in animals but the role in humans is unclear? | Pineal |
| What are the 4 phases of sexual response? | Excitation (arousal), plateau, organsm, and resolution |
| What phase of sexual response is characterized by increased muscle tone and engorgement of sexual organs with blood including nipples, clitoris, penis, and labia minor as well as vaginal lubricants? | Excitation |
| During what phase of sexual human response is the clitoris partially hidden by the swelling labia, the areolae continues swelling and the outer third of the vagina engorges? | Plateau phase |
| During what phase of human sexual response does the men ejaculate and the women have analogous contractions of the uterus and vagina? | Orgasm |
| During what phase of sexual response does the body return to the preexcitation conditions and men enter a refractory period? | Resolution phase |
Created by:
seshelby62
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