lactation

Examples of lactation in the following topics:

• Physiology of Lactation

  • Lactation is the secretion of milk from specialized glands (mammary glands) to provide nourishment to offspring.
  • Lactation describes the secretion of milk from the mammary glands and the period of time that a mother lactates to feed her young.
  • The chief function of lactation is to provide nutrition and immune protection to the young after birth.
  • In almost all mammals, lactation induces a period of infertility, which serves to provide the optimal birth spacing for survival of the offspring.

• Energy Requirements

  • Lactate, created from lactic acid fermentation, accounts for the anaerobic component of cardiac metabolism.
  • At normal metabolic rates, about 1% of energy is derived from lactate, and about 10% under moderately hypoxic (low oxygen) conditions.
  • Under more severe hypoxic conditions, not enough energy can be liberated by lactate production to sustain ventricular contraction, and heart failure will occur.
  • Lactate can be recycled by the heart and provides additional support during nutrient deprivation.
  • Recycling lactate is very energy-efficient in the nutrient-deprived myocardium, since one NAD+ is reduced to NADH and H+ (equal to 2.5 or 3 ATP) when lactate is oxidized to pyruvate.

• Pyruvic Acid and Metabolism

  • If insufficient oxygen is available, the acid is broken down anaerobically, creating lactate in animals and ethanol in plants and microorganisms.
  • Pyruvate from glycolysis is converted by fermentation to lactate using the enzyme lactate dehydrogenase and the coenzyme NADH in lactate fermentation.

• Clostridial and Propionic Acid Fermentation

  • Acetic acid is equally a co-metabolite of the organic substrates' fermentation (sugars, glycerol, lactic acid, etc.) by diverse groups of microorganisms which produce different acids: Propionic bacteria (propionate + acetate), Clostridium (butyrate + acetate), Enterobacteria (acetate + lactate), Hetero-fermentative bacteria (acetate, propionate, butyrate, valerate, etc.)
  • The hydrolyzed compounds are fermented into volatile fatty acids (acetate, propionate, butyrate, and lactate), neutral compounds (ethanol, methanol), ammonia, hydrogen and carbon dioxide.

• Breast Augmentation and Reduction

  • In a breast reduction surgery for re-establishing a functional bust that is proportionate to the woman's body, the critical corrective consideration is the tissue viability of the nipple-areola complex (NAC), to ensure the functional sensitivity and lactational capability of the breasts.
  • Moreover, the correction of gynecomastia (woman's breast) is the analogous, enlarged male-breast reduction surgery procedure, wherein there is no consideration of lactation capability.

• Anaerobic Cellular Respiration

  • The excess amount of lactate in those muscles is what causes the burning sensation in your legs while running.
  • In these muscles, lactic acid accumulation must be removed by the blood circulation and the lactate brought to the liver for further metabolism.
  • The enzyme used in this reaction is lactate dehydrogenase (LDH).

• Biosynthesis and Energy

  • This process utilizes precursors such as pyruvate, lactate, or glycerol .

• Acidosis

  • A rise in lactate out of proportion to the level of pyruvate is termed "excess lactate," and may be an indicator of fermentation due to anaerobic metabolism occurring in muscle cells, as seen during strenuous exercise.

• Types of Catabolism

  • In anaerobic conditions, glycolysis produces lactate, through the enzyme lactate dehydrogenase re-oxidizing NADH to NAD+ for re-use in glycolysis.

• Placenta

  • Human placental lactogen is lactogenic and promotes mammary gland growth in preparation for lactation in the mother.
  • It contributes to the woman's mammary gland development in preparation for lactation and stimulates uterine growth to accommodate the growing fetus.