Cellular communication 8 Flashcards
Which statement is NOT a feature of cell death by apoptosis?
a. apoptosis is genetically programmed
b. cells shrink during apoptosis
c. plasma membranes are intact during apoptosis
d. inflammation in surrounding tissue is common in apoptosis
d. inflammation in surrounding tissue is common in apoptosis
_________is cell death by uncontrolled chaotic cellular events in response to cell injury
Necrosis
Describe what happens during necrosis.
cells swell
DNA condenses and dissolves
plasma membranes are disrupted
cell contents are dissolved and leak out
adjacent tissues undergo inflammatory processes
_____________ is characterized by genetically controlled and programmed cell death pathways
Apoptosis
Describe what happens during apoptosis.
cells shrink
nucleus is systematically fragmented
plasma membranes are intact
cellular contents are usually intact
cell components are packaged into “bite-sized” apoptosomes & digested by phagocytosis, all without causing inflammation in surrounding tissues
Death by apoptosis is a ______ physiologic phenomenon that eliminates cells that are no longer needed and maintains a steady number of various cell populations.
normal
Almost all _____________ drugs cause apoptosis of _______ cells
chemotherapeutic drugs; cancer
What are the two pathways that initiate apoptosis?
the intrinsic (or mitochondrial pathway)
extrinsic (death receptor-initiated) pathway
The intrinsic and extrinsic pathways then converge on the
effector (executioner) pathway
What are the three forms of cell death?
necrosis
apoptosis
autophagic cell death
The main biochemical features of apoptosis are:
activation of caspases
membrane alterations & recognition by phagocytes
DNA, protein, lipid, and cell components break down into “bite-sized” fragments
Two families of proteins are key regulators of apoptosis:
caspases & B-cell lymphoma proteins
Which protein keeps mitochondrial Bax/Bak pores in check in healthy cells?
Bcl-2
What type of cell digests apoptotic bodies?
phagocytes
What leads to the intrinsic (mitochondrial) pathway?
damage to the mitochondria by reactive oxygen species or increases in intracellular Ca2+ result in the opening of large pores
The apoptosome activates ______________ and commits the cell to apoptosis in the intrinsic pathway
caspase-9
The extrinsic pathway is triggered by
extracellular signals bind to transmembrane death receptor
The ____________ converges from the extrinsic pathway with caspase-9 from the intrinsic pathway to converge on the executioner pathway
Caspase-8
Executioner caspases are
3 & 7
In the presynaptic nerve terminal, opioid-activated G protein By subunits block:
a. voltage-gated Ca2+ channels
b. voltage-gated Na+ channels
c. voltage-gated K+ channels
d. voltage-gated Cl- channels
a. voltage-gated Ca2+ channels
B1-adrenoreceptor stimulation of cardiac myocytes produces
positive chronotropic, dromotropic (conduction velocity), inotropic, and lusitropic (relaxation) effects by cAMP-mediated signal transduction pathways
Many signals at endothelial cells lead to the production of
nitric oxide (NO) and vasodilation
Opioids exert _______________________ responses in neurons through G protein-coupled receptor signal transduction pathways
both presynaptic and postsynaptic inhibitory
________________ are the sole known enzymes for terminating cyclic nucleotide signals
Cyclic nucleotide phosphodiesterases (PDE)
_________________ plays a key role in water regulation at the terminal nephron
Vasopressin, also known as arginine vasopressin (AVP) and antidiuretic hormone (ADH)
Opioids exert __________________________ responses in neurons
both presynaptic and postsynaptic inhibitory
In presynaptic neurons, GBy subunits block
voltage-gated Ca2+ channels
Vasopressin plays a key role in BP control at two different tissues:
blood vessels & nephrons in the kidney
______________ are the sole known enzyme for terminating cyclic nucleotide signals.
Cyclic nucleotide phosphodiesterases
Inhibition of SERCA2 is relieved by phosphorylation of:
phospholamban
Endothelial nitric oxide synthase (eNOS) is activated by:
Ca2+/CaM complex
Water reabsorption in principal cells of the collecting duct is increased by the insertion of what protein into the apical membrane?
Aquaporin 2 (APQ2)
