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Assessment 1.2
Cellular Environment and Communication Betweens Cells
Question | Answer |
---|---|
Cytosol | entire amount of fluid or water in the body or total body water |
Intracellular Fluid | accounts for 2/3 of total body water, making up 40% of body weight |
Extracellular Fluid | divided into 2 interstitial fluid and plasma |
interstitial fluid- fluid found in the tissues between the cells | |
plasma- fluid component of blood | |
Both intra and extra cellular fluids contain solutes but their concentration gradient is different this is because of the transport mechanisms across cell membranes | |
The concentration of solute in plasma and interstitial fluid are more identical; this is due to the fact that with the exception of proteins, solutes freely diffuse between plasma and interstitial fluid | |
Edema | capillaries contain gaps or pores between the capillary endothelial cells |
fenestrations- are the pores that allow water and solutes to flow freely out of the capillary | |
bruise- broke the capillaries allowing solutes into the interstitial fluid | |
Blood Brain Barrier- brain capillaries are the foundation of blood brain barriers | capillaries in the brain are much different; do not have fenestrations(pores), which makes the capillaries less permeable to water and solutes; this results in significant barrier to movement of fluids and solutes into brain tissue |
Communication Between Cells | conduction of electrical potential(nerve, cardiac, and skeletal), release of a substance, combination of both |
Secretion of Substance- endocrine,paracrine, and autocrine | |
endocrine- release chemicals called hormones into the BLOOD where they are carried to another location in the body | |
Panacrine- cells secrete substances that diffuse into the extracellular fluid and affect neighboring cells (synaposis) | |
Autocrine- cell secretes substances that affect ITSELF by BINDING to the cell surface receptors (immune cells) | |
Action Potentials | electrical potential from cell to cell |
important in nerve, skeletal muscle, and cardiac muscle | |
Action Potential in Nerve Cells -resting state- the cell has no action potential | |
due to the NA/P ATPase pump- the inside of the cell has fewer positive charges than the outside of the cell | |
Depolarization-nerve cell encounters an acion potential becomes depolarized (voltage-gated sodium channgels open allowing sodium to enter the cell), interior of the cell becomes more positive until it reaches if threshold potential, | |
once that happens all the voltage-gated sodium channels open allowing even more rapid influx of sodium REPOLARIZATION until it reaches (35-50mV) then the channels close then the potassium channels open allowing the potassium to rush out of the cell | |
leaves the cell making it more negative again HYPERPOLARIZATION-potassium channels are slower to respond to voltage changes, the potassium channels remain open longer than necessary to return to the resting potential, the resting potential is overshot as | |
the cell becomes slightly more negative than the resting potential | |
read thru packet for skeletal muscle cells and cardiac | |