Tissues: Cell junctions, interactions, membranes Flashcards
What Is a tight junction?
Zipper-like interlocking conjunction between lateral sides of cells

What protein in tight junctions?
Transmembrane proteins
Function of tight junction
Blocks off intercellular space to keep things from passing between them; Impermeable
Desmosomes Structure
Flailed like structure (like snap/button)
Desmosomes protein
Linker proteins called cadherins
Desmosomes function
Anchors cells to each other; keeps from pulling apart
Gap junction
Channel that helps with communication between cells; direct line into adjoining cell
Gap junction function
Huge role in stimulating cells simultaneously; Near instant communication
Hemidesmosomes
Half of the desmosome button
Hemi desmosomes where?
basal surface of cells
Hemidesmosome function
Helps adhere cell to basement membrane
Tissue Membranes: Epithelial or connective?
What do they do?
Can be Just epithelial or connective tissue or both;
Help coat and line different features of body; Keep it lubricated and in it’s own space
Types of tissue membranes
Cutaneous
Serous
Mucosal
Cutaneous membrane: what and where
Largest tissue membrane: skin
Epithelial layer and underlying connective tissue layer
Serous membranes: Function and where?
Help with cushioning because of serous fluid
Along lining of some body cavities and outside of things like digestive track; membranes that surround heart and lungs
Mucosal membranes: what and where
Line anything that has exposure to outside environment:
-Respiratory tract,
-digestive tract,
-reproductive tract,
-urinary tract
Mucosal membrane structure
2 to 3 layers:
-Epithelial layer
-Connective tissue layer (areolar) Called lamina propria
– smooth muscle layer called muscularis mucosae
Lamina propria
Areolar connective tissue layer In a mucosal membrane with collagen, elastic fibers, fibroblasts, and blood vessels
Stem cells are important for:
Development, healing, and regeneration
Undifferentiated cells
Have not been developed perform different function
The farther along differentiation is stem cell goes…
The less likely that it can turn into another cell type
Stages of stem cells:
- Embryonic stem cells
– Totipotent
– Pluripotent - Adult stem cells
– Multipotent
– Unipotent
Totipotent Embryonic stem cell
Can turn into any cell in the body including placenta and amniotic sac
Pluripotent embryonic stem cell
Committed to only cells of embryo
Multipotent adult stem cells
Can still turn into a variety of cells, but more specific and committed to different pathways:
Ex: Neural stem cells—> dif types ofNervous cells
Unipotent adult stem cells
Precursor to fully mature cell
Limited, but ready to mature to regenerate when needed
