Cellular Pathophysiology and Genetics

Flashcards covering cellular anatomy, mechanisms of injury, metabolic processes, and the genetic basis of various diseases based on the lecture transcript.

Nucleus

Contains RNA, cellular DNA, and proteins; its primary functions are cell division, control of genetic information, replication/repair of DNA, and transcription of RNA.

Transcription

The process occurring in the nucleus where DNA is converted into messenger RNA (mRNA).

Translation

The process occurring in the cytoplasm where an mRNA strand is converted into an amino acid sequence by ribosomes.

Ribosomes

RNA protein complexes that serve as the chief sites for cellular protein synthesis; often referred to as protein factories.

Endoplasmic Reticulum

A network of tubular and flat vesicular structures responsible for protein synthesis, protein folding, transport, and sensing cellular stress.

Golgi Apparatus

A refining plant that packages proteins from the Endoplasmic Reticulum into secretory vesicles and directs traffic within the cell.

Lysosomes

Small organelles containing digestive enzymes used for autolysis (destroying the cell) and heterolysis (digesting foreign material).

Tay-Sachs disease

A lysosomal storage disease caused by a lack of lysosomal enzymes leading to the accumulation of gangliosides.

Mitochondria

The powerhouse of the cell that generates ATP through aerobic metabolism and participates in oxidative phosphorylation; contains an inner membrane with cristae.

Aerobic metabolism

The process of energy production where glucose is converted to pyruvate for the Krebs cycle in the presence of oxygen, yielding a net of $34$ ATP.

Anaerobic metabolism (Glycolysis)

Energy production occurring during hypoxia where glucose is converted to pyruvate and then to lactic acid, yielding a net of $2$ ATP.

Adenosine Triphosphate (ATP)

The universal fuel inside living cells used for the synthesis of organic molecules, muscle contraction, and active transport.

Cytosol

The gelatinous, semi-liquid portion of the cytoplasm that accounts for 55% of total cell volume.

Plasma Membrane

A semi-permeable barrier between the external and internal cell environment that regulates fluid movement.

Glycoproteins

Antigens located on the surface of all cells that play a role in self vs. non-self recognition, allergies, and autoimmune diseases.

Sodium-Potassium Pump

An active transport mechanism using ATPase to move $3 \text{ Na}^+$ ions out of the cell and $2 \text{ K}^+$ ions into the cell.

Cellular Edema

Swelling of the cell that occurs when the sodium-potassium pump fails, leading to the accumulation of sodium and water inside the cell.

Atrophy

A cellular adaptation where cells revert to a smaller size, such as skeletal muscle shrinkage due to paralysis.

Hypertrophy

An increase in individual cell size, which can be physiological (cardiac enlargement from exercise) or pathological (heart tissue enlargement from hypertension).

Hyperplasia

An increase in the number of cells in tissues capable of mitosis, such as estrogen-stimulated breast cell growth or keloid formation.

Metaplasia

The replacement of one cell type with another due to genetic reprogramming, often to ensure survival in response to environmental exposure like GERD.

Dysplasia

Deranged cellular growth characterized by cells varying in size, shape, and organization; often a result of chronic inflammation or a precancerous condition.

Neoplasia

New, uncoordinated, and uncontrolled cellular growth that is often used interchangeably with the term tumor or cancer.

Hypoxia

Diminished oxygen to cells and the most common cause of cell injury; results from ischemia, anemia, or pulmonary issues.

Free radical injury

Damage caused by reactive oxygen species containing unpaired electrons that disrupt the plasma membrane; leads to oxidative stress.

Endothelium

The active tissue lining the interior of blood vessels that secretes VEGF, nitric oxide (NO), and endothelin.

Aneurysm

A weakened area of an arterial wall that may rupture, often caused by the shearing force of hypertension.

Atherogenesis

The formation of atherosclerotic plaque triggered by endothelial injury, LDL deposition, and foam cell formation.

Apoptosis

Genetically programmed, organized cell death that does not cause inflammation or adversely affect surrounding tissues.

Necrosis

Irreversible cell death due to injury where the membrane disintegrates, enzymes are released (autolysis), and an inflammatory reaction is initiated.

Infarction

Ischemic necrosis; the death of tissue resulting from prolonged ischemia, such as a Myocardial Infarction (MI).

Gangrene

Tissue death associated with prolonged ischemia, infarction, and necrosis, often involving Clostridium perfringens which emits gas.

Epigenetic changes

Alterations in gene expression caused by environmental stressors, behaviors, or lifestyle rather than changes to the DNA sequence itself.

Karyotype

A picture of the $23$ chromosome pairs in a human, consisting of $22$ pairs of autosomes and one pair of sex chromosomes.

Aneuploidy

A chromosomal alteration resulting in a different number of chromosomes than the normal $46$, such as Trisomy $21$ or Turner syndrome.

Marfan’s syndrome

An autosomal dominant connective tissue disorder caused by a Fibrillin-1 ($FBN1$) gene mutation; often involves the aorta, heart valves, and lungs.

Cystic Fibrosis (CF)

An autosomal recessive lethal inherited disease caused by a defect in the $CFTR$ gene at $7q31$, disrupting lung and pancreatic secretions.

Klinefelter syndrome

A chromosomal abnormality in males characterized by the karyotype $47, XXY$, leading to decreased cognitive development.

Turner syndrome

A chromosomal abnormality in females characterized by a $45, X0$ karyotype, often involving a webbed neck and varying disease severity.

Fragile X syndrome

A disorder of the X chromosome at $Xq27.3$ characterized by long repeating sequences of CGG, leading to cognitive impairment.

Down syndrome

The most common chromosomal disorder (Trisomy $21$), characterized by a flat facial profile and epicanthic folds around the eyes.