Which part of the nervous system increases the secretion of digestive juices?

The sympathetic nervous system is part of the autonomous nervous system which is involved in the stimulation of movements that prepare the body for action, such as increasing the heart rate, raising the release of sugar from the liver into the blood and other flight or fight responses of the body. The parasympathetic nervous system reduces respiration and heart rate and increases digestion by the increase in saliva production and other digestive juices.

Explain the mechanism of respiration.

The process of respiration initiates usually with glucose. Pyruvic acid is formed in the initial stages of aerobic and anaerobic respiration by the breakdown of glucose. The process of formation of pyruvic acid is called Glycolysis or EMP Pathway (Embden-Meyerhof-Parnas Pathway). EMP process does not require O 2 , but it can also take place in the presence of oxygen. After this step, pyruvic acid's fate is decided by the presence or absence of oxygen. In the presence of oxygen, the complete oxidation of pyruvic acid into H 2 O and CO 2 occurs and the chemical reactions involved in it are called the Tri-Carboxylic Acid cycle (TCA Cycle) or Krebs Cycle. Kreb's cycle occurs in mitochondria. In the absence of oxygen, pyruvic acid forms ethyl alcohol (C 2 H 5 OH) and CO 2 in the cytoplasm. This process is called anaerobic respiration.

Draw a labelled diagram of human respiratory system.

The respiratory system consists of nostrils, windpipe, lungs, and diaphragm. The atmospheric air that contains oxygen enters the lungs through the nostrils and windpipe. From the lungs, oxygen gets dissolved in the blood and reaches all the parts of the body.

Respiration is a chemical process where oxygen is taken in and which reacts chemically with food in the body and metabolize it and release carbon dioxide and energy. The energy released during respiration is essential for the survival of the organism.

Which nutritive element is found in abundance in fish?

Fish is a vital source of food for people. Fish is an important source of protein. Fish proteins are regarded as 'easily digestible' protein. Proteins are required for growth and repair of our body. Fish is rich in calcium and phosphorus and a great source of minerals, such as iron, zinc, iodine, magnesium, and potassium. It is also one of the source of vitamin A and D. Fish contain omega- 3 fatty acids and riboflavin.

Draw a labelled diagram of human excretory system.

Excretion is the process of removal of metabolic wastes from the body. Human beings and other mammals are ureotelic organisms as they excrete urea in the form of urine as an excretory material.

Explain the mechanism of glomerular filtration in urine formation

Glomerular filtration occurs in the glomerulus where blood is filtered. This process occurs across the three layers- epithelium of Bowman’s capsule, endothelium of glomerular blood vessels, and a membrane between these two layers. The glomerulus is a complex network of blood capillaries that is surrounded by Bowman's capsule. It occurs at the barrier between the blood and the filtrate in the glomerular capsule in the kidneys. The pressure of blood and concentration gradients lead to a separation of components through a semipermeable membrane. The product of ultrafiltration is the glomerular filtrate that contains excess water, salts, ions, nitrogenous waste, and nutrients.

The living organisms produce various waste products such as uric acid, carbon dioxide, urea, ammonia, etc as a result of various metabolic reactions taking place in their bodies. The process of removal of wastes from the body is called excretion.