Lipid & Protein Metabolism and Epithelial Tissue Histology

Vocabulary practice flashcards generated from lecture notes covering lipid transport, amino acids, metabolic pathways, cell junctions, and epithelial tissue classifications.

Lipoprotein

A spherical carrier molecule made of lipids and proteins that transports hydrophobic lipids through the blood plasma.

Chylomicrons

The largest and lightest lipid carriers that form on the mucosal layer of the intestine to transport dietary lipids to adipose tissue.

Lacteals

Lymphatic vessels located in the intestinal villi where dietary fats enter, turning the lymphatic fluid milky white.

Very Low Density Lipoproteins (VLDLs)

Endogenous lipid carriers synthesized by hepatocytes in the liver to transport liver-made triglycerides to adipose tissue.

Low Density Lipoproteins (LDLs)

Lipoproteins converted from VLDLs that carry 75% of total blood cholesterol to tissues for membrane repair, hormone synthesis, and bile salt production.

High Density Lipoproteins (HDLs)

The smallest and heaviest lipoproteins, referred to as good cholesterol, which remove excess cholesterol from cells and transport it to the liver.

Lipolysis

The enzymatic breakdown of triglycerides into glycerol and fatty acids to be used as fuel for ATP synthesis.

Lipogenesis

The synthesis process where excess dietary proteins, carbohydrates, or fatty acids are converted into triglycerides for storage.

Beta Oxidation

A metabolic process occurring in the mitochondria that breaks fatty acids into two-carbon acetyl CoA fragments, ultimately yielding ketone bodies.

Deamination

The removal of an amino group from an amino acid prior to entering the Krebs cycle, which produces toxic ammonia.

Essential Amino Acids

The 10 amino acids that the human body cannot synthesize on its own and must obtain directly through the diet.

Phenylketonuria (PKU)

A genetic disorder characterized by the lack of a hydroxylase enzyme needed to convert phenylalanine into tyrosine, leading to a toxic buildup of phenylalanine.

Histology

The microscopic study of body tissues and their organization.

Cytology

The study of individual cells rather than full tissues.

Tissues

Groups of similar cells performing a shared function and sharing a similar extracellular matrix.

Epithelial Tissue

A primary tissue type consisting of closely packed cells with minimal extracellular space that forms body coverings, cavity linings, and glands.

Apical Surface

The top or free surface of an epithelial cell facing toward an open space, cavity, or external environment.

Basal Surface

The bottom surface of an epithelial cell that anchors to the underlying basement membrane.

Basement Membrane

An acellular foundational layer composed of collagen, glycoproteins, and proteoglycans that secures epithelial tissue to connective tissue.

Tight Junction

An intercellular junction created by stitched protein strands that seals the space between adjacent cells to create a impermeable barrier.

Gap Junction

A communicating cell junction formed by aligned protein channels (tunnels) between cells, allowing direct fluid and signaling movement.

Desmosome

A mechanical spot-weld junction where interdigitating cadherin proteins from plaques attach adjacent cells, anchored internally by keratin filaments.

Hemidesmosome

A half-desmosome structure that uses integrin proteins to firmly bind the basal surface of an epithelial cell to the basement membrane.

Adherens Junction

A cell junction similar to a desmosome that utilizes actin filaments around its plaque, enabling contraction and movement control.

Simple Epithelium

Epithelial tissue composed of a single layer of cells where every cell touches the basement membrane.

Stratified Epithelium

Epithelial tissue consisting of two or more layers of cells, designed for protection against mechanical stress.

Pseudostratified Epithelium

Epithelium that appears multi-layered due to staggered nuclei positions, but is actually a single layer where every cell connects to the basement membrane.

Transitional Epithelium

A specialized stratified epithelium in the urinary bladder composed of polyhedral balloon cells that flatten and stretch as the bladder fills.