Ch. 12 - Animal Reproduction & Development

Question 1

Non-animal: Asexual reproduction: benefits from stable environment since offspring are clones; sexual reproduction’s advantage is ___

Answer 1

___

variation

Question 2

___: separation of organism into two new cells (amoeba)

Answer 2

fission

Question 3

___: new individual splits off from existing one (hydra)

Answer 3

budding

Question 4

______: single parent breaks into parts that regenerate into new individuals (sponge/planaria/starfish)

Answer 4

fragmentation and regeneration

Question 5

______: development of egg w/out fertilization; resulting adult is haploid (honeybees, some lizards)

Answer 5

parthenogenesis

Question 6

______ – reproductive structure responsible for production of gametes. Male = testis, female = ovaries (______ sex characteristics)

• ______: indication of sexual maturity but not specifically involved in reproduction (e.g. breasts)

Answer 6

gonads
primary
secondary sex characteristics

Question 7

a. Ovary: ___, or eggs, are produced. Each female has two ovaries.
b. Oviduct: eggs move from ovary to uterus through oviduct (Fallopian/uterine tube); one for each ovary; swept by ___
c. Uterus: fertilized ovum implants (attaches) on the inside wall, ___, of uterus. ___
occurs here until birth.
d. Vagina: at birth, fetus passes through ___ (opening in the uterus), through and out of body.

Answer 7

ova
fimbrae
endometrium
development of embryo
cervix

Question 8

a. Testis: each consists of \_\_\_ for production of sperm and interstitial cells (Leydig cells)
produces \_\_\_ (testosterone = androgen) secreted in the presence of \_\_\_; sertoli cells stimulated by FSH surround and nurture sperm (also secrete peptide hormone \_\_\_, acts on PitGl to \_\_\_ FSH release); testis contained in scrotum-about \_\_\_ lower than body temp for sperm production.

Answer 8

seminiferous tubules
male sex hormones
LH
inhibin
inhibit
2oC

Question 9

b. Epididymis: coiled tube, one attached to each testis; site for ___ and ___ of sperm.
c. Vas deferens: transfer sperms from one epididymis to ___.
d. Seminal vesicles: Two glands, during ejaculation secrete into ___: provide ___ (liquid for sperm),
___ as ATP, and ___ (stimulate uterine contractions that help sperm move into uterus).
e. Prostate gland: secretes milky alkaline fluid into urethra; neutralizes ___ of urine that may still be in urethra,
also ___ acidity. Also neutralizes ___ (too acidic from metabolic waste of sperm)
f. Bulbourethral glands (aka Cowper’s): secrete small amount of fluid of unknown function into urethra.
g. Penis: transport ___ (fluid containing sperm and secretions) into vagina.

Answer 9

final maturation
storage
urethra
vas deferens
mucus
fructose
prostaglandins
acidity
vagina
seminal fluid
semen

Question 10

Sperm: compact packages of DNA specialized for effective male genome delivery.

a. Sperm head: haploid (23 chromosomes); at tip is ___ (a lysosome containing enzymes [hyaluronidase] which are used to penetrate egg-originates from Golgi body vesicles that fused together). Only ___ of sperm enters the egg.
b. Midpiece: flagellum (___ microtubule array), lots of ___.
c. Tail: remainder of flagellum; sperm is propelled by ___ motion of tail and midpiece.

Answer 10

acrosome
nuclear portion

9+2
mito

whiplike

Question 11

SEVEnUP

Answer 11

seminiferous tubules
epidydmis
vas deferens
ejaculatory duct
urethra
penis

Question 12

1. Oogenesis: being during ___; oogonia (fetal cells) -> (mitosis) ___ -> (meiosis) and remain at Prophase I until ___ (one primary oocyte during each menstrual cycle-28days, stim’d by ___) continue its development through remainder of meiosis I within follicle (protects and nourishes oocyte) -> (completion of Meiosis I) secondary oocyte (___) + polar body (small cytoplasm; may or may not divide but products disintegrate) formed; now arrested at metaphase of meiosis II until -> ___

Answer 12

embryonic development
primary oocyte
puberty
FSH
most of cytoplasm
ovulation

Question 13

2. Ovulation: releases secondary oocyte from ___ (caused by ___ surge). If fertilized by sperm -> (finishes meiosis II) ___ (diploid once completely fertilized) + polar body (degenerate)

Answer 13

vesicular follicle
LH
ovum/egg

Question 14

3. Spermatogenesis: begins at ___ within ___ of testes. ___ cells -> (mitosis) primary
   spermatocytes -> (meiosis) 2 secondary spermatocytes -> (meiosis II) 4 spermatids.

Answer 14

puberty
seminiferous tubules
spermatogonia

Question 15

Sertoli cells: in seminiferous tubules provide ___ to spermatids as they differentiate into mature spermatozoa
(sperm). They complete maturation (gain motility and are stored) in the ___.

Capacitation – penultimate step in maturation of the spermatozoa while in the vagina, allows for ___

Answer 15

nourishment
epidydmis

egg penetration

Question 16

1. Female Reproductive Cycle: ovarian cycle (___) + menstrual cycle (___).
   a. Menstrual Cycle – divided into ___, ovulation, ___, menstruation (proliferative/secretory/menstruation) -______ initiate: monitor estrogen and progesterone in blood;
   ___ -> hypothalamus -> GnRH -> FSH and LH (via anterior pituitary-___) ->
   Follicle develops -> FSH stimulate follicle to secrete estrogen -> lots of estrogen (___ on AP) -> LH Surge -> ___ (follicle is now ___-maintained by ___ [which along w/ estrogen begins to
   decrease after ovulation], secretes -> estrogen + progesterone -> Development of endometrium (thickens in prepn for implantation of fertilized egg) -> NO IMPLANTATION OR IMPLANTATION (separate slide)

Answer 16

ovary
uterus

follicular
luteal

hypothalamus/anterior pituitary
low level
negative feedback

positive feedback
ovulation
corpus luteum
LH

Question 17

NO IMPLANTATION:
(___ on AP from ↑e+p) terminates production of ___ (due to ↓GnRH from hypothalamus) -> Corpus luteum (no longer maintained by LH) ___ -> ___, no estrogen + progesterone ->
endometrium ___ during menstruation’s flow phase.

Answer 17

negative feedback
FSH and LH
disintegrates
corpus albicans
shed

Question 18

IMPLANTATION:
If implantation occurs -> embryo (placenta) secretes ___ -> maintain corpus luteum -> Production of e + p remain ___ -> endometrium stays -> HCG is later replaced by ___ from placenta.

Answer 18

chorionic gonadotropin (HCG)
high
progesterone

Question 19

Ovarian Cycle
1.___ : development of egg and secretion of
estrogen from follicle.
2. ___ : midcycle release of egg.
3. ___ : secretion of ___ and ___ from ___ after ovulation.

Estrogen –___ endometrium
Progesterone – development and ___ of endometrial wall

Answer 19

follicular phase
ovulation
luteal phase
estrogen
progesterone
corpus luteum

thicken
maintenance

Question 20

Male Reproductive Cycle:
- GnRH -> FSH + LH (also called___ -> testosterone and androgens from testis).

• FSH and testosterone -> influence ___ to promote development of sperms (nourish sperm during development-spermatogenesis). Hormone and gamete production are ___ unlike female.

Answer 20

ICSH, interstitial cell stimulating hormone

sertoli cells
constant

Question 21

Four stages in growth and development of animal: ___ (sperm/egg formation), ___ (fertilization of egg until birth), ___ (puberty), ___.
- In mammals, development is two stages—___ followed by ___. ___ is an embryo that resembles the infant form.

Answer 21

gametogenesis
embryonic development
reproductive maturity
aging process to death
embryonic
fetal development
fetus

Question 22

a. Fertilization: sperm penetrate plasma membrane of ___.
1. Recognition: before penetration, sperm secretes ___ that bind with receptor that reside on glycoprotein layer (___-zone pellucida in human) surrounding plasma membrane of oocyte ensures same species fertilization

Answer 22

2nd oocyte
proteins
vitelline layer

Question 23

FERTILIZATION

2. Penetration: plasma membranes of sperm and oocyte fuse, sperm ___ enter oocyte.
3. Formation of fertilization membrane: vitelline layer forms fertilization membrane ___ (due to ___: exocytosis of enzymes produced by cortical granules in egg cytoplasm during fertilization – slow block when seen in mammals)
4. Completion of ___ in 2nd oocyte: sperm penetration triggers ___; ovum + polar body (discharged through plasma membrane) produced.
5. Fusion of nuclei and replication of DNA: sperm and ovum nuclei fuse -> ___ (diploid-23 pairs in human).

Answer 23

nucleus
blocks additional sperm
cortical reaction
meiosis II
meiosis II
zygote

Question 24

b. Cleavage: rapid cell divisions without cell growth; each cell = ___ (less cytoplasm than original zygote)
1. Embryo polarity: egg has upper, animal pole and lower, vegetal pole (contain more yolk material which is denser than cytoplasm, ___; differentiates into ___ that protect+nourish embryo). Animal cell can divide through mitosis at a faster rate. (?)

2. Polar and equatorial cleavages: early cleavages are polar, dividing egg into segments that___ (segments of orange); others are ___ with equator.
3. Radial and spiral cleavages: radial in ___ forming (___) cells at animal and vegetal poles that are aligned together, top cells ___ bottom cells. In protostomes (___-determinate), cells formed on top are ___ relative to those below.
4. Indeterminate and determinate cleavages: ___ (blastomeres can individually complete normal development if separated). ___ cannot develop into complete embryo if separated; each is differentiated into part of the embryo.

Answer 24

blastomere
settles at bottom
extraembryonic membranes

stretch from pole to pole
shifted relative

deuterostomes
inderterminate
directly above
spiral
shifted

indeterminate
determinate

Question 25

c. Morula: successive cleavage results in ___ of cells (~8+ cells stage) (first 8 cells are ___) d. Blastula: cell division continues; liquid fills morula and pushes cells out to form circular cavity surrounded by single layer of cells. ___ is the cavity. (~128 cells stage). (get a good picture for this and make sure it distinguishes how the mammalian blastocyst has an inner cell mass) - In humans the blastula is called the ___ and implants into the endometrium (development here) e. Gastrula(tion): ___ into blastula, forming ___ embryo with an opening from outside into center cavity.

Answer 25

``` solid ball totipotent blastocoel blastocyst invagination two-layered ```

Question 26

1. Three germ layers: ectoderm, mesoderm, and endoderm (3rd layer is formed between outer and inner layer of invaginated embryo). Give rise to all subsequent tissues. a. ___ – epithelial lining of digestive & respiratory, parts of liver, pancreas, thyroid, and urinary bladder lining b. ___ – musculoskeletal, circulatory system, excretory system, gonads, connective tissue, portions of digestive & respiratory, notochord c. ___ – Nervous system (brain and spinal cord), integument (epidermis & hair / epithelium of nose, mouth, anal canal), sense structures (lens of eye, retina), teeth, neural tube Note: some primitive animals (e.g. sponges, cnidarian) will develop ___, a noncellular layer, instead of mesoderm

Answer 26

endoderm mesoderm ectoderm mesoglea

Question 27

2. Archenteron: center cavity formed by ___. | 3. Blastopore: opening into ___, becomes mouth (___) or the anus (___).

Answer 27

gastrulation archentron protostomes deuterostomes

Question 28

Extraembryonic membrane development – In birds, reptiles, and humans (called ___ develops as follows: 1. Chorion: outer membrane. Birds and reptiles: membrane for ___. Mammals: chorion implants into endometrium, and later, the chorion and maternal tissue form the ___ (a blend of maternal and embryonic tissues across which gases, nutrients, and wastes are ___) 2. Allantois: Sac that buds off from ___ (cavity of gastrula forming primitive gut) that eventually encircles the embryo, forming layer below chorion. Birds + reptiles: initially stores waste products as ___. Later fuses w/ ___ -> membrane for gas exchange w/ blood vessels below. Mammals: allantois transports waste products to ___; eventually forms ___ between embryo and placenta: transporting gases, nutrients, and wastes. Becomes ___ in adults. 3. Amnion: encloses amniotic cavity, a fluid-filled cavity that ___ the developing embryo, much like the ___ cushions internal organs in coelomates

Answer 28

amniotes gas exchange placenta exchanged ``` archentron uric acid chorion placenta umbilical cord urinary bladder ``` cushions coleom

Question 29

EXTRAEMBRYONIC DEVELOPME 4. Yolk sac: In bird___ digests enclosed yolk. Blood vessels transfer nutrients to embryo. In placental mammals, yolk sac is ___, as umbilical cord/placenta delivers nutrients.

Answer 29

yolk sac membrane | empty

Question 30

g. Organogenesis: cells continue to divide after gastrulation -> differentiate -> develop into specific tissues and organs. In chordates: 1. ___: cells along dorsal surface of mesoderm layer form notochord, a stiff rod that provides support in lower chordates. Vertebrae of higher chordates are formed from nearby cells in mesoderm. 2. ___: In ectoderm layer ___ notochord, layer of cells forms neural plate. Plate indents, forming neural groove, then rolls up into a cylinder, the neural tube. This develops into the CNS. Additional cells roll off top of neural tube and form ___ (which form teeth, bones, muscles of skull, pigment cells in skin, and nerve tissue)

Answer 30

notochord neural tube directly above neural crest

Question 31

Frog: amphibian a. ___: sperm penetrates frog egg -> reorganization of cytoplasm -> pigmented cap of animal pole rotates towards point of penetration while gray, crescent-shaped region forms opposite the point of penetration. Spemann found in early cleavage, each ___ could develop into a frog only if it had a small portion of gray crescent. b. Gastrulation: blastopore forms at border between gray crescent and vegetal pole. During gastrulation, cells migrate over top edge (___-formed from same region previously occupied by gray crescent) of and into blastopore in process called involution; blastocoel disappears and replaced by a different cavity (the archenteron). (this is confusing, see here for in depth explanation). Bottom edge of blastopore -> ___, side -> ___. c. Yolk: more extensive than sea urchin; cells from vegetal pole rich in yolk material form ___ near dorsal lip.

Answer 31

``` gray crescent individual cell dorsal lip ventral lip lateral lip yolk plug ```

Question 32

Bird a. ___ : yolk of bird egg is very large, not involved in ___ ; cleavages only occur in blastula that consists of flattened, disk-shaped region that sits on top of yolk (blastodisc). b. ___ : when gastrulation begins, invagination occurs along line called primitive streak (rather than a ___ ). As cells migrate into here, results in an elongated blastopore rather than circular as in sea urchins and frogs.

Answer 32

blastodisc cleavages primitive streak circle

Question 33

Humans and most other mammals: a. ___: blastula stage consisting of two parts—outer ring of cells (___) and inner mass of cells (___). -Inner cell mass goes on to form the ___ and ___; ___ is what gives rise to the endo/epi/mesoderm. b. ___: accomplishes implantation by embedding into endometrium; produces ___ to maintain e+p production from corpus luteum (which in turn maintains endometrium); it later forms the ___ (later forms placenta). c. ___: within cavity created by trophoblast, ___ clusters at one pole and flatten into embryonic disc (analogous to blastodisc of birds and reptiles). ___ develops -> gastrulation -> development of embryo + extraembryonic membranes (except chorion)

Answer 33

``` blastocyst trophoblast embryonic disc epiblast hypoblast epiblast ``` trophoblast human chorionic gonadotropic (HCG) chorion embryonic disc inner cell mass primitive streak

Question 34

Factors that Influence Development 1. Influence of ___: cytoplasmic material distributed ___ in egg, non-uniform distribution of cytoplasm (think gray crescent in frogs and yolk in bird eggs) results in embryonic axes, such as animal and vegetal poles. When cleavages divide egg -> daughter cells have different quality of ___ (cytoplasmic ___). -> Unique substances influence subsequent development of each daughter cell. (Sea urchin: slice 8-ball embryo into two halves. Longitudinal -> embryo has cells from animal & vegetal pole -> normal development results. Horizontal -> embryo only has cells from animal OR vegetal -> abnormal development results. Confirms the cytoplasmic determinants affecting development. Spemann confirmed with gray crescent vs none cuts.)

Answer 34

egg cytoplasm unequally cytoplasmic substances determinants

Question 35

Factors that Influence Development 2. ___: influence of one cell/group of cells over neighboring cells; ___ (controller cells) secrete chemicals that diffuse among neighboring cells, influence their development (Dorsal lip [fxning as a primary organizer] of blastopore induces ___ in nearby cells); 2nd dorsal lip grafted to embryo -> two ___ developed.

Answer 35

embryonic induction organizers notochord development notochords

Question 36

Factors that Influence Development 3. ___ genes: control of development by turning on and off other genes that code for substances that directly affect development. ___ homeotic genes in fruit flies -> wrong body parts in wrong places. ___ (unique DNA segment-180 nts) identifies a particular class of genes that control ___ (encodes homeodomain of protein that can bind DNA)

Answer 36

homeotic mutant homeobox

Question 37

Cell is said to be ___ if its final form cannot be changed; cytoplasmic influences narrowed by successive cell division; determination likely later than earlier. Trace cells during development to build ___.

Answer 37

determined | lineage map

Question 38

Labor (three stages) – a series of strong uterine contractions 1. Cervix thins out and dilates, ___ ruptures and releases fluids 2. Rapid contractions followed by birth 3. Uterus ___ and expels umbilical cord and placenta ___ twins result from more than one egg being fertilized;___ twins result from indeterminate cleavage

Answer 38

amniotic sac contracts fraternal identical