action potential - The process by which excitable cells transmit information from one to another.
How is the action potential altered by a potassium imbalance? (Hyperkalemia) - The ECF has more K+
ions. The membrane potential becomes more positive (hypopolarized).
How is the action potential altered by a potassium imbalance? (Hypokalemia) - The ECF has less K+ ions.
The membrane potential becomes more negative or hyper-polarized.
The cell becomes less excitable, depolarization takes longer, and takes a stronger stimulus.
Causes weakness, atony, cardiac dystrhythmias.
How is the action potential altered by a calcium imbalance? (hypercalemia) - Increase in ECF calcium to
>10.5 mg/dL. It decreases the cell permeability to calcium.
The cell becomes hyperpolarized (the distance between membrane potential and threshold potential
widens).
The cell is less excitable and take more stimulus to depolarize.
,Atrophy - Catabolism of intracellular organelles causing a reduction in the intracellular contents.
The cell shrinks
-The thymus gland shrinks in childhood
-Disuse atrophy
hypertrophy - Hormonal stimulation in response to increased demand than causes an increase in cellular
protien.
The cell gets larger - eventually causing the whole organ to get larger.
-Skeletal muscle hypertrophy in the weight lifter.
-Cardiomegaly in response to hypertensive heart disease.
Hyperplasia - Increase in the number of growth factor cell receptors that activate cellular proliferation.
Only happens in cell capable of mitosis.
-Increased number of cells.
-Uterine and mammary glands in pregnancy.
-Increased production of endometrial cells due to estrogen/progesterone imbalance.
Dysplasia - abnormal changes in cell size, shape or organization in response to cell injury or irritation.
Not a true adaptive process.
-Cervical dysplasia.
Metaplasia - Mature cell type is replaced by a different mature cell type.
-Reversible, but can induce metestatic change.
-Result of chronic stressor to the cell.
-Chronic smokers who loose normal ciliated epithelial cells (columnar) and the cells are replaced with
squamous cells.
-Barrett's esophagus: Normal esophogeal epithelial cells are replaced with columnar type cells that are
more like the intestine to withstand the acidity of reflux.
, hypoxic injury - Most common type of cellular injury. Caused by lack of oxygen, loss of hemoglobin,
decrease in RBC production, cardiopulmonary disease, ischemia and inflammation. Causes
mitochondrial disfunction ↓ decreased ATP production, ↑ anaerobic metabolism, metabolism ceases,
cell dies.
-Ischemia progresses to hypoxia. Causes intracellular enzymes to show up in labs.
-Creatinine kinase - indicates muscle injury.
-LDH - muscle, liver, lungs, heart, RBCs and brain.
-AST - liver cells
-ALT - liver cells
-Troponin - heart
Reperfusion injury - Occurs when O2 supply is restored to ischemic tissues.
Causes pH alterations.
Trigger reactive oxygen intermediates to be produced causing cell membrane damage and
mitochondrial calcium overload. Causes opening of MPTP allowing ATP to escape causing apatosis.
Free radical and Reactive Oxygen Species - Caused by a molecule with one unpaired electron. They will
steal from another electron and cause that electron to become a free radical. ROS can overwhelm the
mitochondria (they are a free radical subspecies)
-Caused by endothelial injury and leads to atherosclerosis.
-ROS have roles in Alzheimers, ALS, Parkinsons. ROS cause lipid peroxidation and destroy the cell
membrane. Lipid peroxidation damages proteins and fragments DNA.
Causes inflammation, fatty liver, hepatomegaly and liver failure.
-Metabolized by the liver to for acetyaldehyde in the cytoplasm of the cell.
-Eventually causes lactic acidosis which prevents gluconeogenesis, increases triglycerides and
heapatsteatosis.
-Causes the utilization of Acetyl-CoA, causing ketoacidosis and hepatosteatosis.
Necrosis - Cell death from damage or injury.
The benefits of buying summaries with Stuvia:
Guaranteed quality through customer reviews
Stuvia customers have reviewed more than 700,000 summaries. This how you know that you are buying the best documents.
Quick and easy check-out
You can quickly pay through credit card or Stuvia-credit for the summaries. There is no membership needed.
Focus on what matters
Your fellow students write the study notes themselves, which is why the documents are always reliable and up-to-date. This ensures you quickly get to the core!
Frequently asked questions
What do I get when I buy this document?
You get a PDF, available immediately after your purchase. The purchased document is accessible anytime, anywhere and indefinitely through your profile.
Satisfaction guarantee: how does it work?
Our satisfaction guarantee ensures that you always find a study document that suits you well. You fill out a form, and our customer service team takes care of the rest.
Who am I buying these notes from?
Stuvia is a marketplace, so you are not buying this document from us, but from seller VasilyKichigin. Stuvia facilitates payment to the seller.
Will I be stuck with a subscription?
No, you only buy these notes for $13.48. You're not tied to anything after your purchase.
