abBio lab quiz

white, tough outer covering

Viscous fluid that fills eye

1st lens, transparent, no blood vessels

Ring of muscles, colored part of eye, contracts/relaxes in response to light

Keeps image in focus

converts light into electrical signals through optic nerve, responsible for central and color vision, responsible for peripheral vision

contains neurons that connect to the brain

• 1. Optic vesicle: close proximity to the non-neural ectoderm to induce lens placode.
• 2. lens placode: invaginates to form the lens vesicle.
• 3. optic vesicle: forms the optic cup and stimulates lens induction.
• 4. cornea develops from ectoderm
• 5. retina differtiation of several layers of cells

cell to cell interaction that determines the fate of a group of cells.

• Sperm entry point gives the zygote symmetry
• -Anterior/posterior
• -Left/right axes

• Animal
• Vegetal

Rapid miotic divisions without cell growth (cell stays the same size)

• Increase - mitosis
• Decrease - DNA sythesis

Individual cells

Latin for mulberry

Blastomeres move to edges to form a hollow ball

• Blastocoel:
• Fluid inside the blastula

Invagination: animal pole moves toward vegetal pole

Blastopore: opening

• Archenteron: cavity

• 3 layers:
• Ectoderm: skin, nervous system
• Mesoderm: muscles, circulatory system, cartilage, bone
• Endoderm: internal organs, gut lining

• Deuterostomes (echinoderms, chordates)
• -Blastopore forms the anus

• Protosomes (mollusks, arthropods, annelids)
• -Blastopore forms the mouth

• Yolk:
• Evenly distributed
• Sparce

• Holoblastic cleavage
• Complete division of egg into blastomeres
• eg: seastars, mammals

• Yolk:
• vegetal pole
• moderate pole

• Holoblastic cleavage
• -complete division of egg into blastomeres
• -cells divide slower at vegetal pole (yolk is thicker) ...faster in thinner part
• eg: amphibians

yolk: throughout and dense

• Meroblastic cleavage:
• only a portion of the egg divides into blastomeres (in upper portion by nucleus)

• Discoidal cleavage:
• a type of meroblastic cleavage resulting in a disk of cells at the animal pole

• eg: reptiles, birds

blastodisc: area at animal pole without yolk

ingression: cells of blastoderm migrate and turn in at the primative streak

Cleavage is restricted to blastodisc (telolecithal)

• Primative streak:
• The same as the blastopore in the sea star

• 1) nervous system develops from ectoderm
• 2) epidermal cells move centrally
• 3) neural plate folds
• 4) folds elevate and come together
• 5) closing forming neural tube
• 6) neural crest cells migrate to form various structures
• 7) the neural tube then develops into the central nervous system.

• 1. Heart develops from mesoderm
• 2. paired tubes fuse, blood flows from bottom to top (25-30hrs)
• 3. S-bend (about 33hrs)
• 4. Folds onto self into a loop, atria on the top and ventricles on the bottom (48hrs)
• 5. Divsion into chambers (72hrs)

• growth
• differentiation - specialization of cells (eg: muscles or nerves)
• organogenesis - organis
• morphogenesis - body begins to take shape