Bio 111 lecture 20

what are the two types of drugs that target receptors?

agonists and antagonists

what do agonists do?

mimic the action of ligands and activate receptors

what do antagonists do?

bind to receptors without activating them, blocking other ligands from binding to the receptor

is nalaxone/narcan an agonist or antagonist?

antagonist

what receptor does narcan bind to?

opioid receptor

what is embryonic development?

a process of gene-directed changes that occur after fertilization that lead to the formation of an organism

what are the four subprocesses of embryonic development?

cell division, cell differentiation, pattern formation, morphogenesis

what is involved in cell division?

cleavage

what is involved in cell differentiation?

cells become particular types

what is involved in pattern formation?

cells detect positional information within the embryo, a body plan takes shape

what is involved in morphogenesis?

development and final shaping of specific anatomical structures

what is cleavage?

when animal cells have a period of rapid cell division following fertilization

do cells grow during cleavage?

no, they only divide

what determines a cell’s developmental fate in cell differentiation?

exposure to ligands

physical contact with other cells

cells ultimately adopt a fate appropriate for their ________ in the embryo

location

in what stage can cells become any cell type?

fertilization through 16-cell morula

in what stage can cells become any cell type except placenta?

blastocyst stage

in what stage can cells become only a few cell types?

three primary germ layers

in what stage can cells become only one cell type?

somatic cells

what is totipotency?

when cells can become any cell typewh

what is pluripotency?

when cells can become any cell type except placentawh

what is multipotency?

when cells can become a few cell tyoeswh

what is unipotency?

when cells can only become one cell type(fully differentiated)

what do radially symmetrical embryos develop?

axes that define the basic body plan

what is polarity?

the qcquisition of axial differences in an embryo

what are the two axes in polarity?

anterior-posterior

dorsal-ventra

what does morphogenesis result from?

changes in: cell growth and differentiation, cell shape, cell migration, or cell death

what is apoptosis?

programmed cell death

what cells go through apoptosis in development?

webbing in fingers and toes

what is an example of failure of morphogenesis?

syndactyly