7111 cell attachments and connective tissue

what is epithelial tissue made of?

polyhedral cells that are very strongly attached, small amount of ECM (cells close together)

what does epithelial tissue do?

• protective lining (can be specialized)

• absorption (intestinal lining)

• secretion (parenchymal gut cells)

what is connective tissue made of?

many cell types, some fixed some not, lots of ECM, ECM ground substance

what does connective tissue do?

• support and protect structures

• attach to epithelial tissue

• stores interstitial fluid, water, electrolytes, and immune cells

are epithelial cells vascular?

no, connective tissue is

how do epithelial cells get nutrients

defusal through basement membrane.

how are the epithelial poles oriented?

• basal (faces CT)

• apical (faces lumen)

what is the basement membrane

a thin sheet of ECM anchoring the epithelium to CT

what 3 zones make up the basement membrane?

• lamina lucida (light layer)

• lamina densa (thick collagen layer T4)

• lamina fibroreticularis (other collagen anchors)

what type of epithelium is single layered?

simple

what type of epithelium is multilayered?

stratified

what three epithelium cell shapes are there?

• squamous

• cuboidal

• columnar

what is the role of the cytoskeleton?

structure, movement, and attachment, contractility

what are cytoskeleton microfilaments?

• actin

• can be remodeled

• structure and movement

• 6-8nm

what are cytoskeleton intermediate filaments?

• made of many tissues, mainly vimentin

• non contractile

• anchors, structural

• 10nm

what are cytoskeleton microtubules?

• tubulin

• monorail system (kinesis), cilia and flagella (dynein)

• 25nm

What type of cell attachment allows for narrow gaps between cells? it maintains polarization of the cell and allows cell signaling pathways (like to stop replicating).

Tight junction

what cell adhesions bind to actin filaments?

• tight junctions

• cell-cell

• focal adhesion

tight junctions with more protein strands are ______________?

tighter than those with less

why are cell to cell adhesive junctions important?

hold cells together and provide contact inhibition (prevents cells from over replicating)

what cell attachment holds cells to ECM?

focal adhesions (like cell -cell, also use vinculin to attach to actin filaments)

what component of focal adhesion junctions have a role in cell signaling, and interact with ECM matrix proteins?

integrins (like cadherins for cell-cells)

what are the inside and outside complexes of cell-cell adhesive junctions?

cadherins (out), CatINins (in)

what call attachments use vinculin and actinin to attach to actin filaments?

cell-cell and focal adhesions

cell-cell junction function

Cadherin, CatINins, Ca2+, Contact inhib

(REMEMBER Cs)

what are desmosomes?

• strong cell-cell adhesion

• attach to intermediate filaments

• form electron dense plaques on the cells

• Desmoglein (out) and desmocollIN (in)

• resist shearing forces

• not impermeable like a tight junction

what are hemidesmosomes?

• Cell- basement membrane strong adhesion

• attach to intermediate filaments

• plaques formed

• resist shear

what are gap junctions?

• cell cell aqueous and ion pores

• propagation of electrical signals

what are the permanent connective tissue types?

• fibroblasts

• adipocytes

• macrophages

• mast cells

what are the transient CT cell types?

• plasma cells

• lymphocytes

• neutrophils

• eosinophils

what is the main CT cell? they make collagen and ECM (tissue repair)

fibroblasts

how do fibroblasts connect

actin connections from integrins to fibronectin in ECM

Major synthetic product of cells derived from the mesenchyme

collagen

Elastin, made by fibroblasts form into fibers how?

fibrillin 1 and 2 form microfibril scaffold, elastic fibers accumulate on to the scaffold

what is the function of adipocytes?

• lipid energy reserve

• insulation and cushioning

• major endocrine organ

what is the structure and makeup of the connective tissue ground substance?

gel like substance

• proteoglycans

• glycoproteins

what main component of CT ground substance are a protein core with GAGs

proteoglycans

what stored in the CT is released upon injury for repair? can be stored by proteoglycans

growth factors

what charge to proteoglycans have?

Negative, hydrophilic

proteoglycans are specialized ________________.

glycoproteins

What kind of CT is more cell dense and fewer in fibers? It is for support and form but not rigid structure.

loose CT

what kind of CT is very abundant in fibers and has less cells? It provides structure in one or multi directions.

dense CT

what makes regular dense CT different than irregular?

fibers in one direction (tendons and ligaments)

what makes irregular dense CT different than regular?

multidirectional fibers = multidirectional movement (skin)

where is loose CT found?

fills spaces between tissues and organs, surrounds lymphatic and blood vessels.