Tissues Test - 57

RBCs contain pigment hemoglobin which helps in the transport of oxygen to body cells. Thus, RBCs are oxygen carriers. Option A is correct.

Average life span of an RBC is 120 days. About 1% of RBCs are destroyed and replaced every day. There are around 4.5 - 5 million RBCs per cubic millimeter of blood. 

Sensory neurons receive sensory inputs from the internal and external environment and transmit it to CNS (brain and spinal cord) for processing.  Motor neurons transmit the nerve impulses from CNS to effectors (muscles and glands).  According to the signal, carried by motor nerves to effector organs, the muscles and glands perform their actions (contraction and secretion respectively) and thereby coordinating the metabolic activities. 

The RBC count is the total number of red blood cells per cubic millimeter of blood. In response to hypoxia, the hormone erythropoietin, secreted by the kidneys, stimulates the bone marrow to produce red blood cells. The formation of red blood cells is known as erythropoiesis. Normal red blood cells values at various ages are: 

The fibrous tissue connecting two bones is called the ligament. Ligaments are very elastic and have considerable strength.

So, the correct answer is 'Ligament'.

• Meristematic tissues: These tissues have the capacity to divide. They have a thin cellulose wall. They do not have intercellular spaces. They contain dense cytoplasm with a prominent nucleus. They contain many small vacuoles in their cytoplasm. They produce permanent tissues. They are responsible for the primary and secondary growth of the plants. 
• Permanent tissues: These tissues have lost the capacity of division. They have a thick cellulose wall. They have large intercellular spaces. They contain a thin cytoplasm with a normal nucleus. They contain a single large vacuole in their cytoplasm. They are produced by meristematic tissues. These tissues add to the various growths.

Answer: (C) Both A and B

• Areolar connective tissue is made of cells and an extracellular matrix. The matrix has two components, fibers, and ground substance. It consists of fibroblast which secretes collagen, macrophages which help in phagocytosis, and mast cells which help in the allergic and inflammatory response. These are absent in adipose, cartilage, and compound epithelium. 

The water content in the human body refers to the water contained in the tissues, blood, bones and elsewhere and makes up the significant fraction of the body weight and volume. On an average, the adult human body contains between 60-65% water, which is nearly 2/3 of the body weight.