1. Give reasons for the following
a) Matrix of bone is made up of calcium.
b) Presence of contractile proteins in the muscles.
c) Animals of colder regions and fishes of cold water have a thick layer of
subcutaneous fat. Name this tissue.
d) Columnar Epithelial tissue present in the respiratory tract has cilia.
Answers
Explanation:
1:-Bone matrix
The hardness and rigidity of bone is due to the presence of mineral salt in the osteoid matrix, which is a crystalline complex of calcium and phosphate (hydroxyapatite). Calcified bone contains about 25% organic matrix (2-5% of which are cells), 5% water and 70% inorganic mineral (hydroxyapatite).
2:-Contractile proteins of muscle are actin and myosin, the main components of the thin and thick filaments, respectively. ... The thin filaments extend from the Z lines; they are formed by the actin molecules twisted in a helix. Each molecule has a myosin-binding site for the myosin head. Muscle Contraction.
3:-adipose
Describe why the animals of colder regions and fishes of cold water have a thicker layer of subcutaneous fat. Subcutaneous layer or adipose tissues are the fat depositing layers found just below the skin or in between internal organs. They reduce heat loss from the body and act as a good insulator.
4:-The conducting passageways of the respiratory system (nasal cavity, trachea, bronchi and bronchioles) are lined by pseudostratified columnar epithelial tissue, which is ciliated and which includes mucus-secreting goblet cells. ... This epithelium is exceedingly thin to facilitate diffusion of oxygen and CO2