Fill in the blanks using appropriate words given in the bracket. (Haemoglobin, alkaline, diaphragm, red bone marrow, acidic, voluntary, involuntary,)

a. RBCs of the blood contain ----------, an iron compound.

b. ---------- is present between thoracic and abdominal cavity.

c. Cardiac muscles are ----------.

d. pH of oxygenated blood is ----------.

e. Production of RBCs occurs in ----------.

(a) Haemoglobin

Explanation: Larger and more-complex animals, which have greater oxygen needs, have pigments capable of transporting relatively large amounts of oxygen. The red pigment haemoglobin, which contains iron, is found in all vertebrates and in some invertebrates. In almost all vertebrates, including humans, haemoglobin is contained exclusively within the red blood cells to carry oxygen and transport in throughout the body.

(b) Diaphragm

Explanation: A muscular partition is present at the base of thoracic cage which is called as diaphragm. It is present between the thoracic cavity and abdominal cavity. Simultaneous rising up of ribs and lowering of diaphragm causes the decrease in pressure on lungs. Due to this, air moves into the lungs through nose. When ribs return to their original position and diaphragm rises up, pressure on the lungs increases. Due to this, air moves out from it through nose. Continuous upward and downward movement of diaphragm is necessary to bring about the breathing.

(c) Involuntary

Explanation: The muscular system consists of all the muscles in the body. This is the body system that allows us to move. You can control some muscle movements. However, certain muscle movements happen without our thinking about them. Muscles that are under our conscious control are called voluntary muscles. Muscles that are not under our conscious control are called involuntary muscles.

We also depend on many muscles to keep you alive. Our heart, which is mostly muscle, pumps blood around our body. The cardiac muscle fibres all contract together, generating enough force to push blood throughout the body.

(d) alkaline (basic) - 7.4

Explanation: pH is a logarithmic scale used to specify the acidity or basicity of an aqueous solution. Blood pH is regulated to stay within the narrow range of 7.35 to 7.45, making it slightly basic. Blood that has a pH below 7.35 is too acidic, whereas blood pH above 7.45 is too basic. The oxygenated blood is deep red colour, salty in taste and its pH is 7.4.

(e) Red bone marrow

Explanation: Bone marrow is the tissue comprising the centre of large bones. There are two types of bone marrow: red marrow (also known as myeloid tissue) and yellow marrow. Red blood cells, platelets and most white blood cells arise in red marrow; some white blood cells develop in yellow marrow.

Production of red blood cells is controlled by erythropoietin, a hormone produced primarily by the kidneys. Red blood cells start as immature cells in the bone marrow and after approximately seven days of maturation are released into the bloodstream.