Chapter 27 Flashcards
Sexual reproduction is biparental, meaning offspring receives genes from__
two parents
is offspring genetically identical too either parent?
no
what are sex cells called
gametes
gametes are produced by each parent and contain
their genetic information
what are the male and female gametes
sperm (spermatozoon) and egg (ovum)
gametes combine to form a
zygote
what is another name for a fertilized egg
zygote
Our cells contain ___ pairs of chromosomes
23
__ pairs of autosomes
22
_ pairs of sex chromosomes
1
the chromosomes are __ for male and __ for female
XY, XX
Males produce 1/2 __ carrying sperm and 1/2 __ carrying sperm
Y, X
all eggs cary the __ chromosome
X
the sex of the child is determined but he type of __
sperm that fertilizes the egg
what are autosomes
chromosomes that are not your sex chromosomes
what are the functions of the male reproductive system
produce sperm and introduce sperm into the female body
what are the functions of the female reproductive system,
- produces eggs
- receives sperm
- provides for gametes’ union
- harbors fetus
- nourishes offspring
what is another name for the primary sex organs
gonads
what do the primary sex organs do
produce gamete
what are the primary sex organs of the male and females
testes and ovaries
what are secondary sex organs
organs other than gonads that are necessary for reproduction
what are the secondary sex organs for males
system of ducts, glands and penis
what are the secondary sex organs for females
uterine tubes, uterus, and vagina receive sperm and harbor developing fetus
what are some intersex conditions
Discrepancy between a person’s genotype and their external genitalia
Genotypic sex vs Phenotypic sex
what is the difference between genotypic and phenotypic sex
genotypic-chromosomes given during birth
phenotypic- the appearance of one
what are the male external genitalia
penis and scrotum
what are the female external genitalia
- mons pubis
- labia majora
- labia minora
- clitoris
- vaginal office
- vestibular bulbs
- vestibular glands
- paraurethral glands
what are the male internal genitalia
- testes
- epididymides
- ductus deferentes
- seminal vesicles
- prostate
- bulbourethral glands
what are the female internal genitalia
- ovaries
- uterine tubes
- uterus
- vagina
what are the telltale signs of androgen-insensitivity syndrom
a girl will show all the signs of puberty but fails to menstruate
what causes androgen-insensitivity syndromn
- presence of testes in the abdomen
- Karyotype of XY chromosomes
- Testes produce normal male levels of testosterone
- Target cells lack receptors for it
- No ovaries, uterus, vagina, or menstruation
what are secondary sex characteristics
features that appear as sexual maturity is approached and play a role in mate attraction
what are secondary sex characteristics of both sexes
Pubic and axillary hair and their associated scent glands, and the pitch of the voice
what is are the secondary sex characteristics of males
Facial hair, coarse and visible hair on the torso and limbs, relatively muscular physique
what are the secondary sex characteristics of females
Distribution of body fat, breast enlargement, and relatively hairless appearance of the skin
true or false: there is overlap between sexes in the secondary sex characteristics
true
true or false: Initially, a fetus is sexually undifferentiated
true
when do gonads begin to develop
5-6 weeks as gonadal ridges
there are __ sets of ducts adjacent to gonadal ridges
two
In males, __ ducts develop into reproductive tract; __ ducts degenerate
mesonephric, paramesonephric
In females, ___ducts develop into reproductive tract; ___ ducts degenerate
paramesonephric, mesonephric
the __ gene is only in males
SRY
what does SRY gene stand for
sex determining region of the Y chromosome
SRY codes for what protein
testes-determining factor
what does testes determining factor do
initiates development of testes
Testes begin to secrete testosterone at __ weeks stimulating the __ducts to develop into male tracts
8 to 9, mesonephric
at 8-9 weeks the testes secrete __ causing degeneration of the paramesonephric ducts
müllerian-inhibiting factor
true or false: estrogen levels lower in pregnancy
false, estrogen levels are always high win pregnancy
If estrogen was the hormone that directed female development, all fetuses would be
female
Female development of a fetus occurs whenever there is an absence of
androgen hormones
__ becomes the head (glans) of the penis or glans clitoris
Genital tubercle
Pair of __ encloses male urethra helping to form the penis or forms the labia minora
urogenital folds
Pair of __ becomes either scrotum or labia majora
labioscrotal folds
By week __, either male or female genitalia are distinctly formed
12
Male and female organs that develop from the same embryonic structure are __
homologous
Penis is homologous to the
clitoris
Scrotum is homologous to the
labia majora
Urogenital makes __ or body of penis
shaft
what does homologous mean
one structure is from the same embryonic structure
Gonads initially develop high in the__ and then migrate into the __ (ovaries) or scrotum (testes)
abdominal cavity, pelvic cavity
Descent of the testes begins as early as __ weeks
6
In seventh month, testes pass through the __ canal into the __ guided by the __
inguinal, scrotum, gubernaculum
Testes accompanied by __
- elongating testicular arteries 2. veins
- lymphatic vessels
- nerves
- spermatic ducts
- extensions of internal abdominal oblique muscle
what is the term for undescended testes
Cryptorchidism
Cryptorchidism occurs in about __% of male births
3
in most cases of Cryptorchidism the testes descend within the first __ of infancy
year
what can aid in making the testes descend
testosterone injections or simple surgery
what can uncorrected cases cryptorchidism lead to
sterility or testicular cancer
the ovaries lodges on the __ of the lesser pelvis during descent
inferior brim
__ becomes a pair of ligaments that supports the ovary and the uterus
Gubernaculum
what is the perineum and what occupies it
diamond shaped area between the thighs, scrotum and penis
what is the scrotum
sac of skin, connective tissue and muscle that contains the testes
why do the human testes reside in the scrotum
because of its cooler environment
the __ testis is usually lower so they are not compressed
left
what is the spermatic cord
bundle of connective tissue, muscle, blood and lymphatic vessels, and nerves
Right testicular vein drains to
inferior vena cava
Left testicular vein drains into
left renal vein