ANS 2 - Midterm 1

what is the largest cell created in the female body

egg

what is the smallest cell created in the male body

sperm

zona pellucida

protective barrier of egg

when does fertilization occur

when sperm penetrates egg

where does fertilization occur

in the oviduct

what type of egg does sperm penetrate

oocyte

what is created when egg is fertilized

zygote

zygote

single celled stage after fertilization

name the eight parts of the female repro tract starting from the furthest inside the body

1) ovaries

2) infundibulum

3) oviduct

4) uterine horns

5) uterus/uterine body

6) cervix

7) vagina

8) vulva

function of ovaries

where hormones and eggs are produced

function of infundibulum

to catch the egg that is released by the ovary

function of oviduct

where fertilization occurs

function of uterine horns

where fetus is developed

function of uterus/uterine body

serves as a canal into the uterine horns

function of cervix

prevents infection and foreign bodies from entering rest of repro tract

what feature of the cervix prevents infection and foreign bodies from entering

crypts

what do crypts do outside of preventing infection and foreign bodies

they are groves within the cervix that temporarily store sperm while they wait for the egg to be released allowing for extended release of the sperm

function of vagina

copulatory organ that connects outside of repro tract to inside of repro tract (serves as birth canal)

function of vulva

opening from the outside of the body into the repro tract

what is the location of the urinary bladder and why is it important to consider in reproductive biology of most mammals

the bladder is located below the repro tract as to prevent urine from entering repro tract given that they both exit the vulva

where in the egg is sperm implanted during fertilization

zona pellucida

what is the benefit of the length of oviducts

allows time for the fertilized egg (zygote) to develop on its way to the the uterine horn and send signals to female that pregnancy is occurring

fill in the blank: _________ species have larger uterine horns

litter-based

where is sperm deposited in sows and why

sperm is deposited into the uterus because the boar uses its corkscrew penis to bypass the cervix which is very complex

which uterine horn do fetuses develop in in sows

both

what are the three types of uteri

1) simplex

2) duplex

3) bicornuate

explain the three characteristics of a simplex uterus

1) has no horns

2) one uterine body

3) fallopian tubes instead of oviducts

what animals have a simplex uterus

primates

name the two characteristics of a duplex uterus

1) two cervixes

2) two repro tracts

what two types of animals have a duplex uterus

1) marsupials

2) rabbits

name the four characteristics of a bicornuate uterus

have different stages of uterine horn development

what are the three stages of development of a bicornuate uterus and identify an animal that connects to each type

1) poor uterine horn development (mares)

2) moderate uterine horn development (cows)

3) high uterine horn development (sows)

identify the seven parts of testicular anatomy starting from inside the testicle

1) seminiferous tubules

2) head of epididymis

3) body of epididymis

4) tail of epididymis

5) vas deferens

6) pampiniform plexus

7) spermatic cord

function of seminiferous tubules

where spermatogenisis happens

function of head of epididymis and formal name

function: where the earliest stages of sperm maturation begin

name: caput

function of body of epididymis and formal name

function: where sperm continue to mature

name: corpus

function of tail of epididymis and formal name

function: where most mature sperm reside

name: cauda

function of vas deferens

transports sperm from epididymis to seminal vesicle

function of pampiniform plexus

blood vessels that drain gonads for heat exchange

function of spermatic cord

holds testicles to body

how long does it take for sperm to mature

depends of species, but days to months

why and how can a stressor affect sperm for large periods of time

stressors make the animal infertile by killing the sperm and because it can take sperm a while to fully mature, it takes time for enough sperm to mature to be fertile

what two things reside in the seminiferous tubules

1) leydig cells

2) sertoli cells

what function do leydig cells perform and and where are they located around the seminiferous tubules

function: produces testosterone

where: outside the seminiferous tubules

what prompts the production of testosterone from the leydig cells

LH

what function do sertoli cells perform and and where are they located around the seminiferous tubules

function: protects sperm

where: inside the seminiferous tubules

define hormone

chemical substance produced by specialized ductless glands

function of hormones (overall)

drives reproduction of both genders

how do hormones drive reproduction

they are released into the blood stream and carried to other parts of the body to produce a specific regulatory effect

regulatory effect

reproductive effects that happen in the body due to hormones

what is each hormone created for

for a specific duty in a specific target cell

describe the three step process of regulatory effects in specific cells

1) hormones activate receptors on the surface of the target cell

2) the hormone binds to DNA of the cell

3) triggers second messengers to carry out the duty

fill in the blank: the hypothalamus links the _______ system to the _______ system

the hypothalamus links the nervous system to the endocrine system

what are the five cells within the anterior pituitary that make the six hormones

1) somatrope cell makes growth hormones (GH)

2) corticotrope cell makes adrenal gland hormones (ACTH)

3) thyrotrope cell makes thyroid stimulating hormones (TSH)

4) lactotrope cell makes lactation hormones (PRL)

5) gonadotropic cells make gonadotropins (LH, FSH)

what hormone does the posterior pituitary make

oxytocin

what do gonadotropins do

regulate sex hormones and stimulate the release of LH and FSH

what does FSH do in males and females

males: stimulates sertoli cells in the testes to begin spermatogenisis

females: induces follicle growth in ovaries

what does LH do in males and females

males: stimulates leydig cells to produce testosterone

females: stimulates estrogen production in ovaries and ovulation

fill in the blank: GnRH release is regulated by _______ and ________ input

GnRH release is regulated by neural and hormonal input

what four inputs affect GnRH release

1) age

2) weight/nutrition

3) temp/season

4) repro state of testes

define feedback system

provides balance for the system by tightly regulating hormonal controls

define the two types of feedback systems

1) negative- when output changes or reaches proper levels then further output will be suppressed

2) positive- hormonal output begins because of a stimulus

name three characteristics of a negative feedback system

1) it is the most common way to regulate hormones

2) hormone levels are detected by the brain or pituitary

3) prevents overstimulation (turns on and off)

what is the three step process of a positive feedback system

1) stimulus begins hormonal output

2) hormone is secreted to target cells

3) target cells sends message back to hypothalamus and pituitary to continue secretion

what three things happen after the leydig cells stimulate testosterone production

testosterone is secreted into various tissues resulting in:

1) the development and maintenance of repro organs

2) grows muscle and bone

3) influences behavior and libido

name seven characteristics of sertoli cells

1) act as a physical barrier between blood vessels and seminiferous tubules

2) keeps sperm within the tubules so it can’t get into the blood stream and cause an immune response

3) can detoxify fluids around the tubules

4) keep seminiferous tubules open so that spermatogenisis can occur there

5) provides nutrients to sperm within the testes to support their metabolism

6) not enough FSH prevents sertoli cells from developing and protecting sperm

7) provides structure to seminiferous tubules to make one way direction for sperm

meiosis

cell division that produces gametes

what is the five step process of meiosis in males

1) mitosis provides the supply of spermatogonia stem cells

2) spermatogonium- spermatogonia stage (before becoming a sperm)

3) primary spermatocyte- male’s genetic info doubles into diploids

4)secondary spermatocyte- the doubles split off from each other (ex: twins getting separated at birth)

5) spermatid- the diploids split into haploids signifying the beginning of spermatogenesis (spermatids/immature sperm before maturing into spermatozoa)

where does sperm meiosis take place

seminiferous tubules

why are there diff stages of sperm development within the seminiferous tubules

because spermatogenesis occurs in waves

proximal droplet

round ball on sperm tail that can tell the sperm’s age depending where it is located on the tail

where is the age timeline of the proximal droplet on a sperm’s tail

• closer to head = younger

• farther down tail = more mature

• no droplet = fully mature

what is the sperm overall designed to do

to reach and penetrate the egg

what are the two features of a mature sperm

1) head

2) tail

what are three characteristics of a sperm head

1) contains the DNA/nucleus

2) different sperm head shapes for different animals

3) has a cap on the sperm head

what is the cap on the sperm head called and what does it do

acrosome- contains enzymes to help penetrate egg

what enzyme does the sperm cap contain

hyaluronidase

what is the tail of the sperm called

flagella

what is the purpose of the sperm tail

gets the head/DNA to the egg

what are the three parts of a sperm’s tail and what do they do

1) principal piece- propels/moves the sperm (part of flagella)

2) midpiece- contains mitochondira that provides energy for locomotion

3) end piece- propels/movies the sperm (part of flagella)

spermatogenesis

the process of differentiation from diploid germ cell (spermatogonia) to haploid gamete (spermatozoa); when sperm becomes sperm

spermatogonia

germ cell made by male body

spermatozoa

the actual sperm used in repro

fill in the blank: spermatogenesis is tightly regulated by the _________

HPG axis

fill in the blank: if not properly regulated by the ________, then ________ will be affected

if not properly regulated by the HPG axis, then fertility will be affected

fill in the blank: the ________ acts as temporary storage as sperm matures

epididymis

boar taint

testosterone causes the production of androstenone (pheromone) and skatole (bacteria) in the liver that changes the taste and smell of the boar’s carcass

where is androstenone produced

testes

what are the two solutions to boar taint

1) castration before puberty

2) kisspeptin inhibition via gene editing

what is the three step process of inhibiting kisspeptin

1) genetically edit the kisspeptin gene

2) lack of kisspeptin stops the HPG axis and therefore no testosterone

3) no teststerone = no androstenone or skatole

what are two things to consider when editing kisspeptin in boars

1) it shrinks testes

2) it does not significantly inhibit FSH and LH as much as it does the rest of the HPG axis

fill in the blank: if the uterus is not ready to accept the egg, they will ______ the pregnancy

lose

name the four step process of spermatogenesis

1) mitosis- spermatogonia becomes primary spermatocyte

2) meiosis I- primary spermatocyte becomes secondary spermatocyte

3) meiosis II- secondary spermatocyte becomes spermatid

4) spermiogenesis - spermatid becomes spermatozoa

fill in the blank: during the first step of spermatogenesis, the germ cell at the beginning of the process is made by the ______ at __________

during the first step of spermatogenesis, the germ cell at the beginning of the process is made by body at puberty

fill in the blank: during the first step of oogenesis, the germ cell at the beginning of the process is made _____ ______ and mature at ________

during the first step of oogenesis, the germ cell at the beginning of the process is made before birth and mature at puberty

what are three differences between meiosis in males and females

spermatogenesis: four viable sperm cells (gametes) are made; starts at puberty; continuous

oogenesis: one viable egg cell (gametes) and 2-3 polar bodies are made; starts in utero; completed upon fertilization

fill in the blank: ______ drive the female’s reproductive system because they create hormones

ovaries