Molec and Cell Chapter 22

Stem cells

Undifferentiated cell that can divide indefinitely • Found between Paneth cells • Daughter cells can differentiate or remain stem cells

At the Crypt Base Are Multipotent!!!!!!

Committed precursor cells

Cell derived from a stem cell • Divide for a limited number of times before terminally differentiating • Also known as transit amplifying cells

Absorptive cell

most abundant constituent of the epithelium, many microvilli >Absorbs nutrients from the gut lumen ,they produce hydrolytic enzymes to help extracellular digestion

Goblet cells

produce the protective coat of the epithelium by secreting mucus into the gut lumen

Paneth cells

secrete proteins to kill bacteria, part of the innate immune defense system

Create the Stem-Cell Niche!!!

Enteroendocrine cells

secrete serotonin and other peptide hormones that interact with neurons and other gut cells . Regulate growth, proliferation and digestive activities of gut cells and other tissues

Crypts

Lining of the Small Intestine Is Continually Renewed Through Cell Proliferation in the______?

Wnt Signaling

Maintains the Gut Stem-Cell Compartment; Maintains the Gut Stem-Cell Compartment

ACTIVATED BY APC mutation

maintains Notch Signaling

Quiescent Stem Cells

Are Difficult to Identify by lineage tracing, Small, inactive, close contact with mature cell

Muscle damage, Muscular dystrophy, MYOBLAST STIMULATED

Myoblasts

_________ Fuse to Form New Skeletal Muscle Fibers

Bone Marrow

Contains Multipotent Hematopoietic Stem Cells, Able to Give Rise to All Classes of Blood Cells

Stem-Cell Niche

Maintains Stem-Cell Self Renewal

Lgr5

A Single ________ expressing Cell in Culture Can Generate an Entire Organized Crypt-Villus System

Crypt cells

express EphB receptor proteins , and othersGoblet, Absorptive switch on ligands-cell surface proteins Ephrin B

Asymmetric Division of Stem Cells

Choice is determined by asymmetry in dividing stem cell and DOES NOT Have to Become Different

Independence Choice of Stem Cells

Choice is determined stochastically and/or by the environment and DOES NOT Have to Become Different

Notch Signaling

Controls Gut Cell Diversification and Helps Maintain the Stem-Cell State

Cells expressing DELTA, activates Notch

Wnt Signaling maintains NotS

NEOBLASTS

Can Regenerate a Whole New Body

BLASTEMA

Can Regenerate Entire Limbs and Organs

Nuclei

_______Can Be Reprogrammed by Transplantation into Foreign Cytoplasm

CHROMATIN

Reprogramming of a Transplanted Nucleus Involves Drastic Epigenetic Changes in_______?

Embryonic Stem (ES) Cells

Can Generate Any Part of the Body

OCT4 gene in ES, a critical gene!!!!!

Totipotent cells

can give rise to all types of cells

Pluripotent

give rise to MOST, NOT ALL

Not a true stem cell/can be programmed to progressive differentiation

Induced Pluripotent Stem Cells (iPS Cells)

Fibroblasts Can Be Reprogrammed to Create_________