Excretory System and Circulatory System.pdf

Insect Circulatory System Department of Pest Management College of Agriculture and Food Science  Hemolymph Composition It makes up 15–75% of the volume of the insect it contributes to the ability of the insect to live at both high and low temperatures. hemolym...

Insect Circulatory System Department of Pest Management College of Agriculture and Food Science  Hemolymph Composition It makes up 15–75% of the volume of the insect it contributes to the ability of the insect to live at both high and low temperatures. hemolymph consists of the liquid plasma and the cellular hemocytes. Department of Pest Management College of Agriculture and Food Science Functions of the hemolymph circulating hemolymph, or blood, is not important in respiration but functions in transporting nutrients to all parts of the body and metabolic waste products from the organs to the malpighian tubules for excretion Contains hemocytes to help protect the insect  Hemocytes cellular hemocytes (insect blood cells) are suspended in the plasma have a variety of functions: phagocytosis of foreign particulate matter encapsulation of multicellular parasites coagulation and wound healing after injury Department of Pest Management College of Agriculture and Food Science Department of Pest Management College of Agriculture and Food Science Department of Pest Management College of Agriculture and Food Science  Open circulatory system Peristaltic contractions- alary muscles Diastolic phase (relaxation phase) 30-200 beats per minute Department of Pest Management College of Agriculture and Food Science  Accessory Pulsatile Organs Department of Pest Management College of Agriculture and Food Science  Insect Excretory System Department of Pest Management College of Agriculture and Food Science  Excretion defined broadly as any process that eliminates the interaction of harmful substances with cells and tissues Nitrogenous metabolites, ions, water, and ingested chemicals are substances that an insect may need to excrete Department of Pest Management College of Agriculture and Food Science Excretory Organs Malpighian tubules Filter urine from hemolymph Hindgut Secrete and reabsorb some materials Excreta- materials eliminated through anus Nation, 2017  Malpighian Tubules The system is named after Marcello Malpighi, a seventeenth-century anatomist. Ectodermal in origin-no cuticle lining Involved in the secretion of the primary urine Department of Pest Management College of Agriculture and Food Science  Role of of Malpighian tubules and hindgut in excretion Department of Pest Management College of Agriculture and Food Science Nation, 2016  (Chloride-sodium pump) Department of Pest Management College of Agriculture and Food Science  Sodium, chloride, potassium, etc enters the Malpighian tubules either by active or passive transport. Water passive enters the MT and it is controlled by the diuretic hormone. Primary urine is formed from these substances. In the ileum, reabsorption of the Cl, Na, K+ and water occurs. The hemolymph ammonium ions is toxic and reabsorbed by the ilium. It is converted to urate for excretion. The rectum is the last place for reabsorption of ions andwater. In the rectum, potassium, water and small metabolites move back to the hemolymph. Amino acids are resorbed actively. Ammonia is absorbed by the rectum and converted to soluble urate. All (uric acid, alkaloids, ammonium salts) are released as excreta and insects are able to maintain the homeostasis.