Chapter 2.3 Flashcards
What causes sex-linked disorders? Are they recessive or dominant?
- mutations in the gene of the X-chromosome
- most of them are recessively inherited
- > therefore, women inherit less of these sex-linked disorders
- > because they have two sex chromosomes
Why are males termed hemizygous with respect to the X chromosome
-because they have only one copy of each gene on the X chromosome
What is a notable gene on the Y chromosome that initiates testis differentiation
-the SRY gene
What are the two functional parts of the testis
1) seminiferous tubules
2) interstitial cells(of Leydig)
Where are sperm produced in? What are they nourished by?
- sperm are produced in the seminiferous tubules
- >they are nourished by the Sertoli cells
What hormone do cells of the Leydig secrete?
- cells of the Leydig produce testosterone
- >they also produce other androgens
Where is the location of the testies? What is the temperature like there in comparison to the rest of the body?
- the testies is located in the scrotum
- >the temperature there is 2 degrees to 4 degrees lower than the body
Where do sperm gain motility? Where do they go for ejaculation?
- sperm gain motility in the vas deferens
- they go to the ejaculatory duct during ejaculation
Where do the two ejaculatory ducts?
- in the urethra
- >it carries the sperm through the penis as they exit the body
What is the role of the seminal vesicles
- contribute fructose to nourish the sperm
- give sperm fluid mildly alkaline properties
- > so it can survive in the vagina
What is the role of the prostate gland
-give sperm fluid mildly alkaline properties
What is the role of the bulbourethral gland
- produces clear viscous fluid
- > cleans out any remnants of urine
- > lubricates the urethra during sexual arousal
What is semen
-a combination of sperm and seminal fluid
Describe the process of spermatogenesis
-it is the formation of haploid sperm through meiosis
- in males diploid sperm are known as spermatogonia
- after replicating their genetic material in the S stage
- > they develop into primary spermatocytes
- first meiotic division results in secondary spermatocytes
- second meiotic division results in haploids called spermatids
- finally spermatids mature to become spermatozoa
What do mature sperm consist of
-they consist of a head, midpiece and a flagellum
What is the midpiece filled with
- it is filled with mitochondria
- >generates energy as the sperm swims through the female reproductive tract
What is each sperm head covered by
- an acrosome
- >is necessary to penetrate the ovum
What is a major difference between the positioning of the female reproductive organs and the male reproductive organs?
- unlike male reproductive system
- >all female reproductive organs are internal
What hormones do the ovaries produce
-the ovaries produce estrogen and progesterone
Describe where the egg goes after ovulation
- it is released into the peritoneal sac
- > in the abdominal cavity
- it is then drawn into the fallopian tube
- > which is lined with cilia to propel the egg forward
What is the external female anatomy known as
-it is known as the vulva
What kind of oocytes are the oogonia considered to be by birth? What do they develop into after menarche(menstrual cycle)
- by birth
- > all of the oogonia are considered to be primary oocytes
- > these cells are 2n
- > arrested in prophase 1
- develop into secondary oocytes after menarche
- > this is when one primary oocyte completes meiosis 1
- > produces secondary oocyte
- > secondary oocyte remains arrested in metaphase 2
When does the secondary oocyte complete metaphase 2 and finish the remainder of meiosis 2
- the secondary oocyte completes metaphase 2 once fertilization occurs
- > then meiosis 2 is finished
What two layers are the oocyte surrounded by
- surrounded by:
- > zone pellucida
- > corona radiata
What is the purpose of the zone pellucida
- surround the oocyte itself
- > an acellular mixture of glycoproteins
- > protects the oocyte
- > contains compounds necessary for sperm cell binding
What is the purpose of the corona radiata
- lies outside of the zona pellucida
- >layer of cells adhered to the oocyte during ovulation
Is GnRH allowed to be produced prior to puberty?
- no
- > it is only released at the start of puberty
-which then triggers the anterior pituitary to release FSH and LH
What is the role of LH and FSH in males
- FSH is to stimulate Sertoli cells
- > triggers sperm maturation
-LH cells causes interstitial cells to produce testosterone
->maintains male reproductive system
->responsible for secondary sexual characteristics
eg; facial/axillary hair, deepening of the voice and changes in growth patterns
How does testosterone interact with the hypothalamus and the anterior pituitary
-it has a negative feedback on both of these structures
What is estrogen secreted in response to
-it is secreted in response to FSH
->results in the development of the female reproductive system and female secondary sexual characteristics
eg; breast growth, change in fat distribution and widening of the hips
What is progesterone
- secreted by the corpeus luteum
- involved in the development and maintenance of the endometrium
- > not involved in the initial thickening of the endometrium
- > that is the job of estrogen
Describe the characteristics of the follicular phase. When does it start? What hormones are in high amounts during this phase?
- begins when the menstrual flow starts
- higher concentrations of GnRH=higher concentrations of FSH and LH
- the ovarian follicles develop
- follicles begin to produce estrogen
- > estrogen has a negative feedback on the GnRH, LH and FSH
What are estrogen levels like during ovulation
- they reach a threshold
- > results in positive feedback of GnRH, LH and FSH
- > surge in LH is crucial, as this releases the ovum from the ovary
What hormone has high levels in the luteal phase? How does it affect GnRH, FSH and LH
- progesterone
- > it has negative feedback on the three hormones mentioned in the question
What is hCG or human chorionic gonadotropin?
- hormone is an analog of LH
- > maintain the corpus luteum
- it is crucial during the first trimester of development
- > as the corpus luteum secrete estrogen/progesterone
- > this keeps the uterine lining in place
Why do estrogen and progesterone need to be maintained at a high level during pregnancy
-so that there is negative feedback on GnRH secretion
What happens to FSH/LH levels during menopause? Also talk about estrogen and progesterone levels
- since there is no negative feedback on these two
- > blood levels rise
- estrogen and progesterone levels drop
- > so endometrium lining is not maintained
