bio exam 4

What type of reproduction:

offspring are genetically identical (clones) to the parent

asexual reproduction

What is it called when new individuals arise from outgrowths of existing ones

Budding

What is the term:

breaking of the body into pieces, some or all of which develop into adults

fragmentation/regeneration

What is the term:

development of a new individual from an unfertilized egg

parthenogenesis

T OR F: parthenogenesis occurs in some vertebrates

TRUE

Describe the process (brief) of sexual reproduction

male gamete (sperm) and female gamete (ovum) fuse to form a zygote

T OR F: sexual reproduction results in offspring of identical genotypes

FALSE!!! varied genotypes

What is the result of increased variation among offspring

enhances the reproductive success of parents in changing environments

What are the advantages and disadvantages of asexual reproduction

ADV:

simple to produce many copies

can reproduce even if isolates

can produce quickly

DISADV:

only good for stable envs.

little selection pressure for genetic diversity

What are the advantages and disadvantages of sexual reproduction

ADV:

allows for genetic diversity

good for changing envs

DISADV:

requires two individuals

What is gametogenesis

the production of gametes

Where are gametes formed

in gonads

What are the male gonads

testes

What are the female gonads

ovaries

How do germ cells multiply

mitosis

What is the result of mitosis of germ cells (male and female)

spermatogonia (male-2n)

oogonia (female-2n)

Spermatogonia and oogonia multiply again by mitosis to produce what?

primary spermatocytes and primary oocytes

What happens to primary spermatocytes and oocytes after produced

undergo meiosis I and II to form haploid gametes (sperm and egg)

What is the process of spermatogenesis?

spermatogonia, primary spermatocyte, secondary spermatocyte, spermatids, mature sperm

What is the development of sperm (forming a haploid sperm from a diploid sperm) called?

spermatogenesis

T OR F: spermatogenesis is continuous and prolific

true

How much sperm is produces per day

millions

How long does it take each sperm to develop

7 weeks

What is the development of a mature egg called?

oogenesis

Where do immature eggs form in women

in the female embryo

How long does it take for a mature egg to be formed

years or decades

T OR F: All animals have gonads, organs that produce gametes

FALSE, many but not all

Primary spermatocytes undergo meiosis I to produce..?

2 haploid secondary spermatocytes

Secondary spermatocytes undergo meiosis II to produce..?

4 haploid spermatids

Spermatids eventually develop into..?

sperm

During spermatogenesis, one ____ becomes___ ____

one cell, four gametes

What are the part of the sperm

head (with acrosome)

midpiece

tail

What provides energy (ATP) for flagellar movement (mid piece)

Mitochondria

Mitochondria provides energy (ATP) for what in the sperm?

flagellar movement (mid piece)

In oogenesis, how many gametes are produced from each primary oocyte

one

T OR F: one or many ova can develop at a time

true

In mammals, when does oogenesis begin?

in the fetus before birth

Explain oogenesis in the context of puberty and growth

a bunch of germs enter meiosis I and STOP-will not resume development until puberty

What is the process of oogenesis

oogonium replicates chrom to form diploid primary oocyte. po undergoes meiosis I, resulting in small, haploid polar body that will degenerate and a larger, haploid secondary oocyte. the so undergoes meiosis II to form a second polar body which is very small and degenerates. meiosis II also results in a larger, haploid egg

What is the layer of cells that protect and nourish the oocyte called?

cumulus mass

Whats the outer layer of cells that produce hormones which control oocyte growth called?

theca

What is the layer of glycoproteins called?

zone pellucida

In what 3 what does spermatogenesis differ from oogenesis?

1. all 4 products of meiosis develop ssperm whereas only ¼ becomes an egg

2. Spermatogenesis always occurs (adolescence-adulthood) whereas oogenesis mitotic divisions end before birth and gamete production ends around 50 yrs old

   1. sperm are produced continuously w/o the prolonged interruptions in oogenesis

What are the external reproductive organs in males

scrotum and penis

What are the internal reproductive organs in males

1. gonads (testes/testis)

2. accessory glands

3. ducts

What do the gonads do

produce sperm and reproductive hormones

What do the accessory glands do

secrete products essential to sperm movement

What do the ducts in males do

carry sperm and glandular secretions

Each testis is composed of..?

1. seminiferous tubules

2. leydig cells

3. sertoli

Where does spermatogenesis occur?

seminiferous tubules

What hormone do leydig cells secrete?

testosterone

What do Sertoli cells do?

provide nutrients and protection to developing sperm

T OR F: production of normal sperm can occur at any temp

false, cannot occur at the body temps of most mammals

What does the scrotum? What is its purpose?

a fold of the body wall

maintains testis temp at about 2 deg. C below the core body temp

What temp can normal sperm occur?

2 deg C below the core body temp

Where do the testes produce sperm

highly coiled tubes called seminiferous tubules

From the seminiferous tubules of a testis, sperm pass into the coiled duct of the _____, where they complete maturation and become motile

epididymis

What happens in the epididymis?

sperm complete maturation and become motile

During ejaculation, sperm are propelled through what? Where do they exit from?

through the muscular vas deferens and the ejaculatory duct and then exit through the urethra

What is semen composed of?

sperm plus secretions for accessory glands

What contributes about 60% of the total volume of semen (fructose)

seminal vesicles

What secretes its products directly into the urethra through several small ducts (alkaline fluid)

prostate gland

What secretes a clear mucus before ejaculation that neutralizes acidic urine remaining in the urethra (alkaline fluid)?

the bulbourethral gland

What are the 3 male accessory glands

1. seminal vesicles

2. prostate gland

3. bulbouretral glands

What are the 2 external reproductive structures of females?

1. clitoris

2. 2 sets of labia

What are the internal organs in females

1. a pair of gonads

2. a system of ducts

3. chambers that carry gametes and house the embryo and fetus

What are the female gonads called?

ovaries

Where do the ovaries lie?

in the abdominal cavity

What is each ovary packed with?

follicles

What consists of a partially developed egg, called an oocyte, surrounded by support cells

follicles

What makes up the follicles of an ovaru

a partially developed egg, called an oocyte, surrounded by support cells

T OR F: most female mammals are born with all the primary oocytes they will EVER have

true

How many oocytes do females have at birth

1 mil

After degeneration, how many oocytes to women have in each ovary at purbety

200,000 in each ovary

400,000 total

How long does the ovarian cycle last in humans?

28 days

How many oocytes are matures each cycle

one

What is it called when oocytes become depleted and ovulation stops

menopause

flip

-

T OR F: oocytes develop in only ONE of 2 ovaries

true

oocytes are quickly draw into the ______ or _______ by action of fimbriae

oviduct, fallopian tube

Oocytes are quickly drawn into the oviduct or fallopian tube by the action of what?

fimbriae

The secondary oocyte moves down the oviduct by what?

cilia

What do you call a ball of 32 to 150 cells that enters the uterus

blastocyst

How many cells is a blastocyst composed of

32-150

What is the uterus lining called? What is it supplied with?

the endometrium. blood vessels

The neck of the uterus is the _____, which opens into the vagina

cervix

What system are the gonads a part of

endocrine

What is mammalian reproduction regulated by?

1. tropic and sex hormones

2. anterior pituitary

3. gonads

Where are the tropic and sex hormones from?

Hypothalamus

What are the 2 tropic hormones?

1. Luteinizing hormone (LH)

2. Follicle stimulating hormone (FSH)

Where are FSH and LH found

the anterior pituitary

What hormone is secreted by the hypothalamus

GnRH (gonadotropin-releasing hormone)

What hormone directs the release of FSH and LH from the anterior pituitary

What does it mean when a hormone is tropic?

They trigger endocrine tissues to release other hormones

What do FSH and LH do?

act on the gonads and regulate the production of sex hormones

What is the major androgen?

testosterone

What are the major estrogens?

1. estradiol

2. progesterone

T OR F: both males and females produce androgens and estrogens but differ in their blood conc. of particular hormones

TRUE

Males have testosterone levels about ___ times higher than females

10

What hormone stimulates Leydig cells

LH