anat lab 17: genital systems and gametogenisis Flashcards

1
Q

describe the genital system

A

The genital system is unique in that it is not essential to the survival of the individual. Unlike
other organs, the organs of the genital system are inactive until puberty, when hormones
cause them to grow and become functionally mature structures

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2
Q

what are the functional similarities between male and female systems

A
  • both adult systems produce mature gametes (sex cells). - both systems can store, nourish, and transport the gametes. - both systems produce hormones that are essential to the development and functioning of
    each respective genital system.
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3
Q

what does the male genital system consist of?

A

The male genital system consists of the testes, the ducts (epididymis, ductus deferens,
ejaculatory duct, and urethra), the accessory sex glands (seminal glands, prostate and
bulbourethral glands), and supporting structures such as the scrotum and penis.

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4
Q

describe the testes and the epididymis

A
  1. Paired testes and epididymides (epididymis, singular) are contained in the scrotum. In each
    testis, seminiferous tubules produce sperm and inhibin, and interstital endocrine cells produce
    testosterone. At puberty, testosterone stimulates the development of male secondary sex
    characteristics.
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5
Q

what are 4 male characteristics

A
  1. Prominent Adam’s apple
  2. growth of facial hair
  3. enlargement of larynx and deepening of voice
    4.fat deposits mainly around abdomen and waist
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6
Q

describe the epididymis

A

The epididymis is a site of sperm storage, and of sperm maturation. Peristaltic contractions
of the ducts of the epididymis move sperm into the ductus (vas) deferens.

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7
Q

describe the ductus deferentia

A

The ductus deferentia (deferens, singular) exit the scrotum and enter the pelvic cavity to
loop up over the ureters, and empty into the ejaculatory ducts. Sperm are also stored in the
ductus deferens.

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8
Q

describe the seminal glands (vesicles)

A

The seminal glands (vesicles) contribute a variety of substances to semen, which they
release into the ejaculatory ducts

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9
Q

list 3 substances produced by the seminal glands

A

fructose - provides energy for the sperms

proteins - (seminogelin) forms protective gell around spem

alkaline fluid - neutralize acidic enviro of male urethra and female reproductive tract

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10
Q

describe the prostate

A
  1. The prostate is a doughnut shaped gland that surrounds the superior portion of the urethra.
    It secretes a number of substances into the urethra that contribute to sperm motility and
    viability.
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11
Q

list 2 substances secreted by the prostate

A

prostatic secretions- essential for sperm health and motility

  1. spermine - enhances sperm motility
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12
Q

describe the bulbourethral glands

A

The bulbourethral glands are located inferior to the prostate, with ducts emptying into the
urethra

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13
Q

list 2 functions of the sybstances secreted by the bulbourethral glands

A
  1. alkaline mucus reduces acidity of male urethra and female reproductive tract
  2. lubrication
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14
Q

function of scrotum

A

supporting structure

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15
Q

function of testes and seminiferous tubules

A

paired ovals glands in scrotum. make sperm and produce testosterone

seminiferous tubules - where sperm is produced

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16
Q

epididymis function

A

sperm mature and are stored here

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17
Q

ductus (vas) deferens function

A

conveys sperm during sexual arousal from epididymis toward the urethra by peristaltic contraction

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18
Q

seminal gland (vesicle)

A

pouch-like structure
-secretes seminal fluid and neutralizes acid

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19
Q

ejaculatory duct function

A

delivers sperm into the urethra, adding secretions and additives from the prostate necessary for sperm function, while providing an interface between the reproductive and urinary systems in men

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20
Q

prostate gland function

A

The prostate’s most important function is the production of a fluid that, together with sperm cells from the testicles and fluids from other glands, makes up semen. The muscles of the prostate also ensure that the semen is forcefully pressed into the urethra and then expelled outwards during ejaculation.

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21
Q

bulbourethral (Cowper’s) gland

A

paired glands that are partially embedded in the urogenital diaphragm muscle and are composed of compound tubuloalveolar glands.

Secrete a clear, viscous fluid that lubricates and cleanses the urethra, and neutralizes its acidity in preparation for sperm

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22
Q

prostatic urethra vs membranous urethra vs spongy urethra

A

prostatic (located within the prostate), membranous (the part contained within the perineal pouch), and spongy (located in the spongious body of the penis) parts.

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23
Q

corpus spongiosum penis

A

The corpus spongiosum surrounds the urethra (the tube through which urine and sperm pass from the body). It contains blood vessels that fill with blood to help make an erection and keep the urethra open during the erection.

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24
Q

corpora cavernosa penis

A

One of two columns of spongy tissue that runs through the shaft (body) of the penis. The corpus cavernosum forms most of the penis and contains blood vessels that fill with blood to help make an erection.

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25
Q

external urethral orifice

A

the external opening or urinary meatus, normally located at the tip of the glans penis,

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26
Q

prepuce

A

is a movable sheath of skin that covers the head of the penis

FORESKIN GROSSSS

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27
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A
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28
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29
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30
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31
Q

what do the ovaries produce?

A

After puberty, the ovaries produce oocytes (eggs or gametes) which are released in a process
called ovulation. The ovaries also produce estrogens, progesterone, relaxin and inhibin.

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32
Q

what does the female genital system include?

A

The female genital system includes the ovaries, uterine (fallopian) tubes, uterus,
vagina, external genitalia (vulva) and mammary glands.

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33
Q

describe the ovaries

A

The ovaries are held in place by ligaments attaching them to the uterus, pelvic wall and
peritoneum. Review the stages of follicular development in the ovary - the primordial, primary,
secondary, and tertiary ovarian follicles, corpus luteum, and corpus albicans, as well as the
follicular and granulosa cells.

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34
Q

describe fallopian tubes

A

he uterine (fallopian) tubes are the passageway for sperm to reach the ovulated oocyte,
and they transport the secondary oocyte (or fertilized ovum) to the uterus. The distal end of
the uterine tube, the infundibulum, is funnel-shaped and has fingerlike projections from its
expanded end called fimbriae.

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35
Q

describe the epithelium of the fallopian tubes

A

The mucosal lining of the uterine tubes is made of simple ciliated columnar epithelium, to
move the secondary oocyte (or fertilized ovum) or zygote along the tube, and non-ciliated
secretory cells (peg cells) that provide nutrition for the ovum. The peristaltic contractions of
the circular and longitudinal smooth muscle of the muscularis layer also move the oocyte or
fertilized ovum toward the uterus.

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36
Q

describe the uterus

A

The uterus is the site of implantation of the blastocyst, is the site of fetal development, and
it facilitates birth. It is held in place by a number of ligaments, such as the broad ligament
and round ligaments. The uterus has three layers of tissue: the perimetrium, the
myometrium and the endometrium.

The perimetrium of the uterus is the most superficial layer. It extends laterally to form the
broad ligament. The myometrium has circular, longitudinal and oblique muscle layers whose
contractions expel the fetus from the uterus.

37
Q

which posterior pituitary hormone s causes contraction.

A

The hormone oxytocin, released from the posterior pituitary gland, causes contractions during childbirth and lactation

38
Q

Name the hormone that inhibits contraction of the myometrium

Name two sources of this hormone - why is this hormone produced by two different tissues?

A

Progesterone inhibits uterine contraction and induces uterine relaxation in late pregnancy.

ovaries and the adrenal glands

to perform different functions:
Adrenal cortex
Produces a small amount of progesterone in both males and females. Progesterone from the adrenal glands is mostly converted into androgens and glucocorticoids.
Ovaries
The corpus luteum, which develops from the follicle that releases an egg, produces the majority of progesterone in females. Progesterone from the gonads is mostly carried in the blood to perform its biological functions

39
Q

describe the different layers of the uterus

A

The deepest layer, the endometrium, is divided into two layers, the functional layer
(stratum functionalis) of the endometrium and the basal layer (stratum basalis) of the
endometrium. The functional layer of the endometrium lines the uterine cavity and is shed
each month during menstruation. The basal layer of the endometrium, like other epidermal
basal layers, has a high rate of cell division, allowing it to replace the functional layer of the
endometrium each month. The narrow, inferior portion of the uterus, the cervix, opens into
the vagina.

40
Q

describe the vagina

A
  1. The vagina is the passageway from the cervix to the exterior of the body. The epithelial
    layer of the mucosa is non-keratinized stratified squamous epithelium, while the muscularis
    layer has longitudinal and circular smooth muscles.
41
Q

describe the vulva

A

The vulva is the external female genitals. It consists of the mons pubis, labia majora,
labia minora, clitoris and vestibule.

42
Q

describe the mammary glands

A

The mammary glands located inside each breast are modified sudoriferous glands. They
synthesize, secrete and eject milk in a process called lactation

43
Q

Name an anterior pituitary hormone involved in milk production

A

Prolactin is synthesized by lactotrophs in the anterior pituitary gland.

44
Q

Name a posterior pituitary hormone that stimulates the ejection of milk

A

oxytocin

45
Q

ovary function

A

One of a pair of female glands in which the eggs form and the female hormones estrogen and progesterone are made. These hormones play an important role in female traits, such as breast development, body shape, and body hair. They are also involved in the menstrual cycle, fertility, and pregnancy.

46
Q

uterine tube

infundibulum and fimbriae

A

They function as channels for oocyte transport and fertilization

infundibulum The infundibulum catches and channels the released eggs; it is the wide distal (outermost) portion of each fallopian tube. The endings of the fimbriae extend over the ovary; they contract close to the ovary’s surface during ovulation in order to guide the free egg

fimbriae: are finger-like projections on the ends of your fallopian tubes closest to your ovaries. Each month, your fimbriae catch the egg that one of your ovaries releases during ovulation

47
Q

uterus function

A

The uterus nurtures the fertilized ovum, which passes through the fallopian tube. The ovum then implants into the endometrium, where it receives nourishment from blood vessels exclusively developed for this purpose. As the embryo grows and matures, the uterus expands to accommodate the developing fetus.

48
Q

uterine cavity

A

the triangular-shaped space inside the uterus, a hollow, muscular organ in the female reproductive system

49
Q

endometrium function

A

preparation for implantation, maintenance of pregnancy if implantation occurs, and menstruation in the absence of pregnancy.

50
Q

myometrium function

A

. This is the thick middle muscle layer of the corpus or fundus. It expands during pregnancy to hold the growing baby. It contracts during labor to push the baby out.

51
Q

perimetrium

A

apart from fulfilling protective functions, it helps to maintain the structural integrity of the uterus in addition to anchoring to neighbouring structures of the pelvis such as the broad ligament of uterus and the pelvic floor.

52
Q

cervix function

A

The cervix allows fluids, such as menstrual blood, to pass from the uterus into the vagina

53
Q

cervical canal

A

The cervical canal passes through the cervix. It allows blood from a menstrual period and a baby (fetus) to pass from the womb into the vagina. The sperm travel from the vagina up the cervical canal into the uterine cavity, then into the fallopian tubes to fertilize the egg.

54
Q

ovarian ligaments function

A

The ovarian ligament’s function is to attach each ovary to the side of the uterus and the pelvic wall

55
Q

broad ligament function

A

The broad ligament is believed to hold the uterus in its normal position within the pelvis and maintains the relationship of the fallopian tubes to the ovaries and the uterus, a role that might be important in reproduction.

56
Q

round ligaments

A

The round ligament helps maintain the anteversion position of the uterus during pregnancy.

57
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A
58
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A
59
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A
60
Q

List some of the female secondary sex characteristics brought about by hormones at puberty.

A

ude relative lack of body hair, thicker hair on the head (in some cases), rounded hips/figure, a decreased ability to generate muscle mass at a fast rate, decreased upper body strength, breasts, ability to nurse children, a menstrual cycle, and increased body fat …

61
Q

Why is it important that the vagina be acidic?

A

to prevent infections and other health issues

62
Q

Semen consists of a mixture of sperm and seminal fluid. What is the function of semen?

A

In all species semen carries sperm into the reproductive tract of the female to facilitate fertilizations

63
Q

what happens during interphase prior to meiosis

A

In interphase prior to meiosis, the chromosomes of the diploid parent cell are duplicated. Each
of the 46 chromosomes now consists of two identical sister chromatids attached at their
centromeres.

64
Q

describe meiosis I

A

Meiosis I carefully matches up the two homologous chromosomes in a diploid cell and
then pulls them apart to produce two haploid cells. Homologous chromosomes, the two
chromosomes in a pair, contain genes that control the same genetic trait. If a chromosome
that you received from your mother (the maternal chromosome) holds a gene for eye colour,
then the homologous chromosome from your father (the paternal chromosome) will have a
gene for eye colour.

Meiosis I consists of four phases: Prophase I, Metaphase I, Anaphase I and Telophase I.

65
Q

describe prophase I

A

Prophase I of meiosis is very similar to prophase of mitosis - the chromosomes condense,
the nuclear membrane and nucleoli disappear, and the spindle apparatus forms. In meiosis,
however, two homologous chromosomes each made of two sister chromatids pair up to form
a tetrad in a process called synapsis. At this time, crossing over occurs - the exchange of
segments of genetic material between non-sister (genetically different) chromatids.

66
Q

what happens in metaphase I

A

In metaphase I, the tetrads line up on the metaphase plate.

67
Q

what happens in anaphase I

A

In anaphase I, the tetrads separate, with one chromosome of each homologous pair
(consisting of joined sister chromatids) moving towards each pole. Maternal and paternal
chromosomes are randomly distributed between the two poles, increasing the potential for
genetic variation in offspring.

68
Q

describe the process of telophase I and cytokinesis

A

The processes of telophase I and cytokinesis are similar to those in mitosis, and the
chromosomes of the two daughter nuclei end up grouped at opposite poles. These daughter
nuclei contain only one set of homologous chromosomes and are therefore haploid.

69
Q

what happens during meiosis II

A

After cytokinesis, meiosis II begins. The phases of meiosis II are similar to those of mitosis:
the chromosomes condense in prophase II, and line up on the equatorial plate in
metaphase II. The sister chromatids separate and move to opposite poles in anaphase II,
and the nuclei of the daughter cells reform in telophase II.

70
Q

what is the end result of meiosis

A

four genetically different haploid cells

71
Q

name two methods by which meiosis increases the genetic variability of the genes

A
  1. crossover
  2. independent assortment
72
Q

what is spermatogenisis. describe it

A

In the testes, the formation of haploid sperm cells by meiosis is called spermatogenesis.
The seminiferous tubules are lined with immature cells called spermatogonia.
Spermatogonia are diploid and are the precursor cells for all sperm that a man will produce.
During childhood, these cells are relatively inactive. When the male reaches puberty, the
spermatogonia become active and remain so for life.

Some of the spermatogonia undergo mitotic cell divisions and become known as primary
spermatocytes. Each primary spermatocyte then divides by meiosis I to form two daughter
cells called secondary spermatocytes, which are haploid.

Each secondary spermatocyte undergoes meiosis II to produce two cells called spermatids,
which are haploid. Each spermatid develops a head with an acrosome and a flagellum in a
process called spermiogenesis, becoming a sperm cell or spermatozoan.

73
Q

describe oogenesis

A

In the ovary, the formation of a haploid ovum by meiosis is referred to as oogenesis. The
precursor cell in this sequence is a diploid cell called the oogonium. During fetal development,
oogonia undergo developmental changes and become primary oocytes. It is during fetal
development that oocytes begin meiosis I, but the process will be arrested in prophase I until
puberty.

Each month, starting at puberty, one primary oocyte (2n) completes meiosis I to form two
cells of unequal size, both of which are haploid. The smaller of the two cells is called the first
polar body and contains one replicated chromosome from each homologous pair. The larger
of the two cells is the secondary oocyte, and in addition to having the other replicated
chromosome from each homologous pair, it contains all the cytoplasmic material present
before cell division.

At the time of fertilization, the secondary oocyte completes meiosis II to form two more cells
of unequal size. The larger haploid cell is the ovum, and the smaller is the second polar
body.

Thus, in the female, one oogonium produces a single haploid ovum, whereas in the male each
spermatogonium produces four haploid sperm.

74
Q

what happens to polar bodies produced in oogenesis? Why?

A

During oogenesis, polar bodies are small cells that are usually broken down and die, but can sometimes be important in an organism’s life cycle:
Explanation
During oogenesis, an egg cell (oogonium) divides unevenly during meiosis, resulting in a larger cell and a smaller cell. The larger cell becomes the egg, or ovum, while the smaller cell is the polar body. The polar body contains a small amount of cytoplasm and a redundant set of chromosomes

75
Q

what are autosomes

A

chromosomes which code for traits that are not directly involved in determining the sex of an individual

76
Q

how many chromosomes do humans have

A

Each individual has 22 pairs of autosomes and two sex chromosomes.

77
Q

what is a karyotype and how is the test performed

A

A karyotype is an analysis of an individual’s chromosomes, to see if there is an abnormality.
Identifying abnormalities and determining their role in disease is an important step in
developing new methods for diagnosis and early treatment.

The test can be performed on a sample of blood, bone marrow, amniotic fluid or placental
tissue. Cells are grown in tissue culture, arrested at metaphase (when the chromosomes are
tightly coiled), stained with a dye, and photographed.

78
Q

what are structural abnormalities

A

In the case of structural abnormalities, the chromosome number remains unchanged. A
variety of structural abnormalities exist. The survival of an individual depends upon which
genes are affected. Structural changes include:
inversions, where one segment of a chromosome breaks off an reattaches inverted.
deletions, where a segment of a chromosome breaks off and is lost.
translocations, where two unrelated chromosomes exchange sections.

79
Q

what are numerical changes in a chromosome. What are the two types?

A

Numerical changes result in a chromosome number other than 46. In meiosis, if two sister
chromatids fail to separate in anaphase, one of the resulting daughter cells will have an extra
chromosome and one daughter cell will be missing a chromosome. If the daughter cell with
the extra chromosome eventually forms the zygote, all the cells resulting from the mitosis of
the zygote will have three copies of that chromosome. This is called a trisomy. If the daughter
cell missing the chromosome forms the zygote, then it is termed a monosomy.
Zygotes with abnormal numbers of autosomes rarely survive. Individuals with trisomy 13 or
trisomy 18 may survive until delivery, but rarely live longer than a year. Trisomy 21, also
known as Down syndrome, is the exception.
Abnormal numbers of sex chromosomes are also possible. Individuals may have only one X
chromosome (XO), a monosomy, or may have three X chromosomes (XXX) or two X and one
Y (XXY, Klinefelter syndrome), all of which are trisomies.

80
Q

define mitosis

A

Mitosis is the process of cell division in eukaryotic organisms, during which a single cell divides to produce two genetically identical daughter cells.

81
Q

meiosis definition

A

Meiosis is a type of cell division that reduces the chromosome number by half, producing four genetically unique daughter cells

82
Q

synapsis definition

A

Synapsis is the pairing of homologous chromosomes during meiosis. This happens in prophase I and allows the exchange of genetic material through crossing-over, increasing genetic diversity.

83
Q

haploid vs diploid

A
  • Haploid (n): A cell with one set of chromosomes. Example: sperm and egg cells in humans have 23 chromosomes.
  • Diploid (2n): A cell with two sets of chromosomes (one from each parent). Example: most human body cells have 46 chromosomes.
84
Q

crossing over

A

Crossing over is the process during prophase I of meiosis where homologous chromosomes exchange genetic material. This creates new combinations of genes, increasing genetic diversity in offspring.

85
Q

sister chromatids vs homologous chromosomes

A

Sister chromatids**:
- Identical copies of the same chromosome, created during DNA replication.
- They are connected at the centromere and separate during mitosis or anaphase II of meiosis.

  • Homologous chromosomes:
    • A pair of chromosomes, one from each parent, with the same genes but possibly different versions (alleles).
    • They pair up during meiosis I and exchange genetic material through crossing over.

Example in humans:
- Sister chromatids: Two identical copies of chromosome 1.
- Homologous chromosomes: One chromosome 1 from the mother and one from the father.

86
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88
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