Linoleic Acid
Linoleic acid is an essential polyunsaturated fatty acid containing 18 carbon atoms and two cis double bonds. It is written in fatty-acid shorthand as 18:2 n-6, or 18:2 omega-6. The omega-6 designation means that the first …
Browse the journal
Knowledge
Follow journal articles connected to Alpekin knowledge topics.
536
published entries
Explore articles
Knowledge
Lipid-soluble Antioxidant
A lipid-soluble antioxidant is an antioxidant that preferentially dissolves in or associates with lipid-rich environments rather than aqueous compartments. In biological systems, these environments include cell membranes and circulating lipoproteins. This distribution allows lipid-soluble antioxidants to …
Lipids
Lipids are a broad and chemically diverse group of biological molecules characterized by hydrophobic or amphipathic properties. Some lipids are predominantly hydrophobic, while others are amphipathic, meaning that they contain both water-attracting and water-repelling regions. Unlike …
Lipolysis
Lipolysis is the enzymatic breakdown of triacylglycerols, also called triglycerides, into fatty acids and glycerol. It occurs in many tissues but is especially important in adipose tissue, where large amounts of energy are stored as triglycerides …
Listeria monocytogenes
Listeria monocytogenes is a species of Gram-positive, rod-shaped bacterium that can cause the foodborne disease listeriosis. It is facultatively anaerobic, meaning it can grow with or without oxygen, and occurs widely in environments such as soil, …
Liver Fibrosis
Liver fibrosis accumulates collagen-rich scar tissue after repeated injury, ranging from limited scarring to changes that disrupt liver architecture.
Lower esophageal sphincter
The lower esophageal sphincter, or LES, is a specialized high-pressure zone at the junction between the esophagus and stomach. Its main function is to help prevent the backward movement, or reflux, of stomach contents into the …
Lymphatic System
The lymphatic system is a network of lymphatic vessels, lymph nodes, and associated lymphoid tissues that helps maintain fluid balance, transport material from tissues, and support immune function. Fluid that leaves blood capillaries enters the spaces …
Lymphocytes
Lymphocytes are immune cells that include B cells, T cells, and natural killer cells. These groups perform different tasks in recognizing threats and coordinating or carrying out immune responses. They occur in blood and in lymphoid …
M-Line
The M-line is a protein-rich structure at the center of a sarcomere, the repeating contractile unit of striated skeletal and cardiac muscle. It lies in the middle of the A band, within the central region occupied …
MET
A MET, or metabolic equivalent of task, is a unit used to express the energy cost or intensity of a physical activity relative to a standardized resting value. One MET represents the conventional energy expenditure of …
MET-Minutes
MET-minutes combine activity intensity with time, providing an exposure measure rather than a direct count of calories burned by an individual.
MIND Diet
The MIND diet scores adherence to a defined food pattern for cognitive-aging research, without proving that the pattern prevents dementia in an individual.
Macronutrients
Macronutrients are nutrients required by the body in relatively large amounts. In human nutrition, the three main energy-yielding macronutrients are carbohydrates, fats, and proteins. They provide energy and also supply chemical building blocks needed for normal …
Magnetic resonance imaging (MRI)
MRI creates tissue images from magnetic and radiofrequency signals without ionizing radiation, while still requiring specific safety screening.
Malabsorption
Malabsorption impairs gastrointestinal nutrient absorption, with consequences that depend on which nutrients are affected and the underlying cause.
Malnutrition
Malnutrition is a state resulting from deficient, excessive, or imbalanced intake or utilization of energy or nutrients. In its broad public-health meaning, malnutrition includes undernutrition, micronutrient deficiencies or excesses, overweight, obesity, and diet-related noncommunicable diseases. Malnutrition …
Mastication
Mastication is the process of chewing food in preparation for swallowing. It involves coordinated movements of the jaw, teeth, tongue, and muscles of the face and mouth. These movements break food into smaller particles and repeatedly …
Maximal Exercise Test
A maximal exercise test raises workload toward the person's highest capacity, with results interpreted using the specific protocol's criteria.
Mediterranean Diet
The Mediterranean diet describes related traditional food patterns, with research definitions that vary rather than specifying one universal menu.
Mediterranean Dietary Pattern
A Mediterranean dietary pattern describes the combination of foods across a diet, with research definitions that differ beyond any single ingredient.
Menopause Transition
The menopause transition marks persistent changes in menstrual-cycle timing as ovarian function shifts, rather than one hormone value or symptom alone.
Menstrual Cycle
The menstrual cycle is the recurring sequence of hormonal, ovarian, and uterine changes that prepares the reproductive system for a possible pregnancy. A cycle is counted from the first day of menstrual bleeding to the first …
Metabolic Dysfunction-Associated Steatotic Liver Disease (MASLD)
MASLD classifies excess liver fat alongside specified cardiometabolic risk, with categories that distinguish metabolic disease from other causes.
Metabolism
Metabolism is the complete set of chemical reactions that occur within living cells and organisms. These reactions transform nutrients and other molecules, provide energy for biological processes, and produce materials needed to build and maintain cells …
Micronutrients
Micronutrients are essential vitamins and minerals that the body needs in relatively small amounts. The term includes vitamins such as vitamins A, C, D, E, K, and the B vitamins, as well as minerals such as …
Microvilli
Microvilli are microscopic, finger-like projections of the plasma membrane that extend from the surface of many types of cells. They are especially prominent on absorptive epithelial cells, such as enterocytes lining the small intestine. By increasing …
Mild Cognitive Impairment
Mild cognitive impairment involves measurable cognitive decline while largely preserving daily independence, and does not always progress to dementia.
Mitochondria
Mitochondria are membrane-bound organelles in eukaryotic cells that carry out major parts of aerobic energy metabolism. The singular form is mitochondrion. Their best-known function is producing adenosine triphosphate, or ATP, through oxidative phosphorylation, converting energy released …
Mixed Micelles
Mixed micelles are small, water-compatible aggregates that form in the small intestine from bile salts together with products of dietary fat digestion and other lipids. They commonly contain bile salts, fatty acids, monoacylglycerols, phospholipids or their …
Mobility
Mobility generally refers to the ability to move the body or a joint through a useful range of motion. In exercise and sport contexts, the term is often used to emphasize active, controlled movement through an …
Moment Arm
A moment arm is the perpendicular distance between the line of action of a force and the axis about which that force produces rotation. In human biomechanics, a muscle’s moment arm is therefore the shortest perpendicular …
Monoacylglycerol
A monoacylglycerol (MAG) is a glycerolipid consisting of a glycerol molecule with one fatty acyl group attached by an ester bond. Because glycerol has three carbon positions, the fatty acyl group can be attached at different …
Monocytes
Monocytes are immune cells produced in bone marrow that enter the bloodstream and contribute to innate immunity. They belong to the mononuclear phagocyte system, a group of cells involved in detecting threats and engulfing material. Their …
Motor Neuron
A motor neuron, or motoneuron, is a nerve cell involved in controlling muscle activity. In the somatic motor system, lower motor neurons located in the spinal cord or brainstem send axons to skeletal muscle and provide …
Movement Pattern
A movement pattern describes how body segments work together for a task, with normal variation rather than one universally ideal technique.
Multi-Joint Exercise
A multi-joint exercise is an exercise in which movement occurs at two or more joints during performance. These exercises typically require coordinated action from several muscles or muscle groups. In resistance training, common examples include squats, …
Multicomponent Warm-Up
Multicomponent warm-ups combine different exercise types, with injury-prevention findings that apply to the programs and populations tested.
Muscle Atrophy
Muscle atrophy is a reduction in the size or mass of muscle tissue. In skeletal muscle, it commonly involves shrinkage of individual muscle fibers, seen as a decrease in their cross-sectional area and loss of contractile …
Muscle Fat Infiltration
Muscle fat infiltration describes fat within muscle regions, with imaging results that depend on the anatomical compartment and measurement method.
Muscle Hypertrophy
Muscle hypertrophy increases skeletal-muscle size through lasting adaptation, while strength also depends on neural activation and movement skill.
Muscle Injury
Muscle injury classification distinguishes structural tears from functional disorders, so pain or dysfunction alone does not establish a tear.
Muscle Protein Synthesis
Muscle protein synthesis builds new proteins from amino acids, but lasting muscle growth depends on the balance between synthesis and breakdown.
Muscle Quality
Muscle quality describes functional or compositional features beyond muscle quantity, with measures that capture different aspects of performance.
Muscle Spindle
A muscle spindle is a specialized sensory receptor located within skeletal muscle that detects muscle length and changes in length, including the speed of stretch. Muscle spindles provide the nervous system with information used for proprioception, …
Muscle Temperature
Muscle temperature is the temperature within muscle tissue, also called intramuscular temperature. It is a local measurement: different depths within a muscle can have different temperatures. A reading therefore describes a particular measurement site, rather than …
Muscle–Tendon Unit
A muscle–tendon unit, or MTU, is the functional mechanical system formed by skeletal muscle and the tendinous tissues connected to it. It includes the force-generating muscle fibers together with force-transmitting structures such as tendons and, where …
Muscular Endurance
Muscular endurance is the ability of a muscle or group of muscles to repeatedly produce force or sustain force over time before task-limiting fatigue occurs. It is usually assessed during submaximal muscular work, meaning the resistance …