Caste study on transportation in animals
Answers
Explanation:
All livings beings require food, water and oxygen for their survival and to perform various activities. Food we consume is digested in to simple absorbable substances called as nutrients in the digestive system.
The circulatory system helps in the transport of nutrients in the glucose, amino acids and fats to different parts of the body. Every cell receives absorbed nutrients through the circulating fluid tissue called as blood.
Excretory system is responsible for the removal of waste from different parts of the body. Every cell releases its waste material into the blood to be carried over to excretory organs for expulsion.
2. CIRCULATION IN LOWER ANIMALS
In unicellular organisms like amoeba and paramecium, circulation is brought about by the process of diffusion. Nutrients are delivered to all parts of the cell by diffusion.
In multicellular organisms like hydra and jelly fish, nutrients are circulated in the body by water vascular system.
3. CIRCULATORY SYSTEM IN HUMAN BEINGS
The circulatory system is also known as the cardiovascular system. The circulatory system comprises blood, blood vessels and the heart.
A. Blood
• Blood is a fluid tissue that flows in special tubes called as blood vessels. Different functions of blood are elucidated.
• Blood maintains constant body temperature.
• Blood helps in transportation of food and water from the digestive system in the body to all the cells in the body.
• Blood helps in transportation of oxygen from the respiratory system to the cells present in all parts of the body.
• Blood helps in transportation of harmful and unwanted wastes from the cells to the excretory Blood is made up of plasma and formed elements.
• Blood provides resistance to the body against pathogens and infections they cause in different parts of the body.
CONSTITUENTS OF BLOOD
a) Plasma is the fluid part of blood which contains 90% water. It is pale yellow in colour. It carries nutrients, enzymes and waste materials in it.
b) Formed elements are made up of three different types of blood cells. These include red blood cells, white blood cells and platelets. Each of these cells performs a specific function.
(i) Red blood cells – RBCs are disc-shaped cells which transport oxygen to different parts of the body. The presence of haemoglobin gives blood its red colour. Haemoglobin is an iron-containing pigment that combines with oxygen to form oxyhaemoglobin. As the blood reaches the cells, oxyhaemoglobin dissociates to release oxygen which is supplied to cells. In the cells, carbon dioxide binds with haemoglobin to form carboxy-haemoglobin. In the lungs, carboxy-haemoglobin dissociates to release carbon dioxide which is expelled out.
(ii) White blood cells – These cells are also called as WBCs. These cells are larger than RBCs. White blood cells help in defending the body against infections. White blood cells have the capability of destroying foreign cells. WBCs can move on their own and can enter the areas of infection by passing through the membranes of blood vessels. These are of many kinds – Leucocytes, basophils, neutrophils, eosinophils etc.
(iii) Platelets – Platelets are the non-nucleated irregularly shaped blood cells which bring about clotting of the blood. These are also called as thrombocytes as they release thromboplastin which brings about clotting of blood. Platelets immediately come to the place of injury and lyse themselves to release thromboplastin. The remnants aggregate in large amounts to form a plug on the injury preventing the blood loss.
B. Blood Vessels
• Blood flows through narrow pipe-like structures in the body known as blood vessels.
• These blood vessels transport food, oxygen and waste throughout the body. Blood vessels are of three types namely, arteries, veins and capillaries.