Cell Physiology Flashcards
Large Water soluble (hydrophilic/Lipophobic) molecules and ions do NOT diffuse through the lipid bilayer and therefore generally must use what to enter and exit cells and cross the blood brain barrier or placental barriers?
channels
Of all substances what are least likely to penetrate lipid bilayers ( give 3 examples)
IONs Na+ K+ Cl- etc.
what is it termed when an intracellular vesicle melts into the surface membrane, before opening to the extracellular space and extruding its contents?
exocytosis
What is it termed when he surface membrane invaginates, pinches off, and becomes an intracellular vesicle containing extracellular fluid?
Endocytosis
what is the term for cell drinking?
pinocytosis
What is the term for Cell ingestion and digestion
Phagocytosis
Proteins are reabsorbed from the proximal tubule of the kidney by what?
pinocytosis (cell drinking)
What cells phagocytize bacteria
Macrophages
Neurotransmitters are released from nerve terminals by what process?
exocytosis
What proteins relay (shuttle) messages (signals) from receptors to enzymes?
G proteins
name 5 second messengers (names and abbreviations)
- Cyclic adenosine monophosphate (cAMP)
- Cyclic guanosine monophosphate (cGMP)
- Calcium
- Calmodulin
- Inositol triphosphate (IP3)
Second messenger are specific to what? and explain why?
- Tissue Specific
- a 2nd messenger can produce different effects in different tissues
- Ex. Increased cAMP in the heart increases Ca++, causing increased contractility, however in bronchial smooth muscle increased cAMP decreases Ca++, producing smooth muscle relaxation (bronchial dilation)
An increase in Cardiac contractility is mediated by ____ adrenergic agonist and Brochodilation is mediated by ____ adrenergic agonist; both of these responses involve Gs and adenylate cyclase
CARDIAC Beta 1
Bronchodilation Beta 2
Insulin stimulates what pump?
Na+ — K+ pump
Insulin stimulates the Na+ – K+ pump, which is the reason it is effective in treating Hyperkalemia. how does it do this ?
Insulin by stimulating the Na+ K+ pump, drives K+ into the cells.
why do you need to give dextrose (sugar) when treating hyperkalemia with insulin?
B/c insulin also opens glucose channels, which permits the transfer of glucose into fat and skeletal muscle cells. thus the glucose component prevents hypoglycemia
What beta agonist are also used for treatment of hyperkalemia? and Why? what are 2 common drugs given?
- Beta 2 agonist
- B/c they stimulate the Na+ K+ pump and drive potassium into cells.
- ritodrine and terbutaline (albuterol is also a good one just not listed here in valley)
Normal extracellular (serum) and Intracellular ( cytoplasm) levels: Na+
145
10
Normal extracellular (serum) and Intracellular ( cytoplasm) levels: K+
4
140
Normal extracellular (serum) and Intracellular ( cytoplasm) levels: Ca++
2.0-2.5
«1
Normal extracellular (serum) and Intracellular ( cytoplasm) levels: Mg++
2
50
Normal extracellular (serum) and Intracellular ( cytoplasm) levels: Cl-
105
4
Normal extracellular (serum) and Intracellular ( cytoplasm) levels: PO4--
2
75
Normal extracellular (serum) and Intracellular ( cytoplasm) levels: HCO3-
24
10
what is the most abundant intracellular ion?
K+
What is the most abundant Extracellular ion
Na+
Resting membrane potential is controlled by which ion
K+
the threshold is controlled by which ion
Ca++
if you depolarize do u go more negative or positive?
positive
if you hyperpolarize do you go more negative or positive
negative
what happens to cells with Hyperkalemia
depolarize
What happens to cells with HypoKalemia
Hyperpolarize
what is most responsible for RMP
Potassium efflux (through “leak” channels)
Diffusion of ____ ions into the cells responsible for depolarization of the axon
Sodium (Na+)
Diffusion of ____ ions OUT of the cell is responsible for repolarization of the
K+
when the Na+ channel is in the inactivated state, another action potential cannont be fired… what is this termed
the absolute refractory period
