session 2: cells/tissues + connective/ adipose tissue Flashcards
what are cell junctions?
types?
structures found between adjacent cells, making sure they are tightly adhered together
What are the 3 cell junctions?
Tight junction
Desmosomes
Gap junctions
What are tight junctions ?
impermeable junction that prevents moleculs from passing
What are desmosomes ?
anchoring junctions that bind adjacent cells together
What are gap junctions?
communicating junctions that allow ions and small molecules to pass
All cells sit on..?
basement membrane
How are cells attached to the basement membrane?
Hemi-desmosomes
Focal adhesion
Hemi-desmosome?
While desmosomes link two cells together, hemidesmosomes attach one cell to the extracellular matrix
What are the functions of focal adhesions?
Anchor intraellular actin filaments to the basemment membrane
play a role in call movement “migration of epithelial cells of skin”
What are the functions of integrins?
- attach cell to ECM
- activate signal transductionpathways from ECM to cell upon ligand binding
- immune patrolling
- cell migration
- binding to cells by certain viruses
what are integrins?
transmembrane receptors that facilitate cell-extracellular matrix (ECM) adhesion.
Which of the following is involved in cell migration?
(Gap junctions, desmosomes, focal adhesions, hemi-desmosomes, integrins)
focal adhesions
integrins
which of the following in NOT involved in lateral domain cell contact?
(desomosomes, gap junctions, hemi-desmosomes, tight junctions)
hemi-desmosomes
What is this communication called?
autocrine
Why are cultured cells different than normal cells?
when they come into contact with other cells they stop growing “Contct inhibition”
they have a limitd life span “senescence”
Explain Senescence?
loss of a cell’s power of division and growth
What are gap junctions made of?
channels of Connexon
Explain the paracrine communication?
cell-cell communication in which a cell produces signals/ chemicals to induce changes in nearby cells
Explain the endocrine communication?
Communication between endocrine organs, as they are ductless and secrete directly into the blood stream
Explain the synaptic communication?
Communication between neurons is achieved at synapses by the process of neurotransmission and the release of neurotransmitters
NA - sympathetic
Ach - parasympathetic
Explain the neurocrine communication?
What 3 areas can we find them in our body?
electrical signaling traveling along the nerve and releases chemicals into the blood stream instead of at a synapse
Examples: hypothalamus, posterior pituitary, adrenal medulla
What process involved in cell replacement?
mitosis
Necrosis vs. apoptosis?
explain necrosis?
Physical distrusting through cell injury,
bacterial toxins, or nutritional deprivation
-> cell swells then bursts -> cytotoxic
cellular components spill out -> damage
and inflammation
explain apoptosis?
Bcl-2 protein on outer mitochondrial membrane inhibits apoptosis,
deactivating Bcl-2 initiates apoptosis -> catabolic reactions take place +
enzymes digest cytotoxic compounds and DNA fragments-> Caspases:
target specific proteins in nuclear lamina and cytoskeleton -> cell
repackaged for safe removal -> cell shrink and fragments into small
apoptotic bodies to be phagocytized
What type of cell death causes
1. inflammation?
2. Caspases activation?
- necrosis
- apoptosis
What is meant by Stable cells?
Where can we find them?
Stable cells are cells that multiply only when needed.
They spend most of the time in G0 phase
fibroblasts, endothelium, SMCs
liver, the proximal tubules of the kidney, and endocrine glands
What is meant by Static/ permenant cells?
Where can we find them?
cells that are incapable of regeneration
This includes brain cells, neurons, heart cells, skeletal muscle cells and (RBCs?)
What is inherited exclusively through the maternal lineage?
mitochondia
What is meant by Labile cells?
Where can we find them?
cells that multiply constantly throughout life
including hepatocytes, skin cells, GI tract, and blood cells in the bone marrow
which cell type is associted with cancer and why?
labile/ renewing cells, bcuz constantly dividing cells have a higher risk of becoming malignant and develop cancer, dividing uncontrollably
which cells that are rarely cancerous? why?
muscle cells, since they are not constantly dividing cells “static/ permenant”
which of the following methods of ell communication involve scretion of hormone?
paracrine, endocrine, autocrine, meurocrine, direct contact
endocrine
neurocrine
where can we find anaerobic prokaryotes in our body?
colon
prokaryotes vs. eukaryotes?
Explain Endosymbiosis?
aerobic bacteria wa taken into an anaerobic eukaryote and fomed the mitochondria
what are the 4 basic tissue types?
epithelial
muscle
nerve
connective tissue
what are the 6 specialized connective tissues?
adipose
lymphatic
blood
hemopoietic
cartilage
bone