Animal reproduction

asexual reproduction budding, fission, parthenogenesis

asexual: budding new organism developing from a bud or outgrowth of the parent,

fission involves the splitting of the parent into two or more daughter organisms.

parthenogenesis (production of an embryo from a female gamete without any genetic contribution from a male gamete)

spermatogenesis

oogenesis

describe the hormonal pathway for testosterone

male reproductive system

seminial vesicle: supply furtose to sperm, supply movement

prostate gland: nourish and protect sperm

vas deferenes: transports sperm from epidymidis

epidymidis: sperm undergo maturation

testis: produce testosterone

ovarian cycle

follicular phase: follical develops in prep for ovualtion

• primary oocyte

• support cells grow around

• secondary oocyte ready to go through meiosis 2, ready for ovulation

ovulation: secondary oocyte released from ovary

luteal phase: corpus lutuem produces hormones then decays, helps keep uterun linign of implantation of eggs (shedding)

describe what happens in the follicular phase- oviarian hormone cycle, pituitary hormone cycle, menstrual cycle

• follicle phase increases estradiol , switches to positive feedback stimulating LH (has slight - feedback), progesterone stays same,

• FSH and LH stimulate follicle to develop

• estradiol stimulate development of uterine lining, estradiol keeps FHS and LH low (negative feedback inhibition)

what happens during ovulation

LH surge causes ovulation

FSH also peaks a little

estradiol decreases

progesterone starts to rise

luteal phase and how the cycle restarts again

corpus luteum, LH stimulates corpus luteum to make progesterone

1. corpus luteum makes progesterone and keeps lining around

2. progesterone inhibits LH and FSH and protects uterine lining in case egg gets ovulated

drop in progestrone causes next menstruation cycle

if implantation

corpus luteum does not degenerate, no drop in progesterone, so no menstruation

what happens in the luteal phase

LH stimulates corpus luteum to make progesterone, estradoil starts to decrease, progesterone inhibits LH and FHS, progesterone protects uterine lining

when progesterone drops, what happens?

menstruation starts

birth control

prevents ovulation, - feedback LH and FSH

• if miss a day keeping estrogen and progestin levels high enough to inhibit the surge of luteinizing hormone (LH) needed to release an egg.

  Thickening cervical mucus: making it harder for sperm to reach the uterus.

  Thinning the uterine lining: reducing the chance of implantation.

emergency contraception

• - feedback prevents ovulation, if embyo already implanted, cannot do anything

abortion pill

blocks progesterone receptors to cause shedding of uterine lining including embryo

how spermatozoon fertilizes sea urchin egg,

1. sperm attracted to egg via chemical signals

2. sperm make contact w jelly layer

3. acrosome (tip of head of sperm) reaction enzymes break down jelly layer and viteline envelope, penetrates

4. bindin binds to bindin receptors

5. fusion of cell membranes

6. sperm nuclues enters egg

7. meiosis 2 of egg cell complete

how polysperm is prevented

1. Ca+2 released= depolarization

2. release of ions and solutes from cortical granules into space around plasma membrane

   1. viltiline envelope swells outward and becomes rigid

what is difference between sea urchin egg and human egg

human egg: corona radiata (crown), zone of pellucida, plasma membrane, cytoplasm, yolk granule, polar body

jelly egg: jelly layer, vitelline envelope, plasma membrane, cytoplasm, yolk granule, nucleus

internal fertilization

animals: mammals, reptiles, birds

parental investment often higher, fewer offspringex

external fertlization

animals: amphibians, fish, aquatic invertebrates

sperm released into environment, lower success rate, parental investment lower

oviparity

eggs laid and development occurs outside moms body (birds)vi

viviparity

embryo develops in mom, direct nourishment from placenta- present in cold climates because temperature regulation

what happens during cleavage

1. converting the single-celled zygote into a multicellular embryo. This process involves dividing the zygote's cytoplasm into called blastomeres.

gastrulation

formation of ectoderm, mesoderm, endoderm, makes future gut

what does ectoderm differeintate into

nervous system, epidermis of skin, epithelial lining of mouth and rectum

what does mesoderm make

skeletal, circulatoary, lympahtic, msuclar system, linging of body cavities, dermis of skin

endoderm makes

epithelial lining of digestive respiratory, reproduct, urininary, liver pancreas, htyroid, thymus

compare gestation and development in marsupial mammals and placental mammal

m: shorter gestation period, embryo underdeveloped at birth, goes into pouch to cont development, simpler placenta

e: longer gestation, fetus develops fully in uterus. highly specialized placenta

male reproductive system

1. Testis (Testes)

   • Produces sperm.

   • Secretes testosterone.

2. Epididymis

   • Stores and matures sperm after production.

3. Vas Deferens

   • Transports mature sperm from the epididymis to the urethra.

4. Seminal Vesicle

   • Produces fluid rich in fructose to nourish sperm.

   • Contributes to semen volume.

5. Prostate Gland

   • Secretes an alkaline fluid that protects sperm in the female reproductive tract.

6. Penis

   • Delivers sperm into the female reproductive tract.

   • Also functions in urination.

7. Urethra

   • Conducts urine and semen out of the body

spermatozoon

mature male gamete

ovum

haploid female gamete

intersitial cells of leydid

cells that synthesize testostrone in testes

spermatid

immature spermatozoon that have not developed flagellumg

granulosa cells

cells form corona radiate surrounding egg

sertoli cells

cells that release cytokines that promote spermatogenesis

what happens during each major stage of embryonic development

cleavage, gastrulation, neuraliation, organogenesis

cleavage

• Shortly after fertilization, the zygote undergoes a series of mitotic divisions. These early divisions are called cleavages.

• The resulting smaller cells are called blastomeres.

• Blastula Formation: After several cleavages, a hollow sphere of cells called the blastula forms. The internal fluid-filled cavity is called the blastocoel.

• Key Features:

  • Establishes the early multicellular structure of the embryo.

  • Cell size decreases with each division.

gastrulation

• Cells of the blastula begin to move inward through a structure called the blastopore.

• Formation of Germ Layers:

  • Ectoderm (outer layer): will form the skin, nervous system.

  • Mesoderm (middle layer): will form muscles, bones, blood, and other internal organs, systems

  • Endoderm (inner layer): will form the lining of the gut and other internal organs.

    • cell differentiation

basltopore becomes what

mouth or anus

neuraluation

formation of neural tube

• mesoderm forms notochord- forms neural plate

• neural tube: nneural plate folds inwards becoming neural tube (brian and spinal)

  • neural crest cells form other structures

organogenesis

cells differentiate based on germ layer (ecto, endo, meso)

somite and trophobalst

somite: mesoderm forms msucle and body tissue

trophoblast forms placenta

womens reproductive system

clit

cervix

fallopian tube

urethra

vagina

ovary

labia majora

clit: Erectile tissue containing numerous nerve endings

cervix: muscular sphincter between the vagina and uterus

fallopian tube: Tube in which the egg may be fertilized following ovulation

urethra: Common tube through which sperm or urine can be released

vagina: Tube in which sperm is deposited during mating in a mammal

ovary: produces ova, estrogen, and progesterone

labia majora: Hairy folds of skin that cover the urethral and vaginal openings