Answer:
Pericardial sac has protective tole
Explanation:
Pericardial sac or pericardium is a fibrous tissue that surrounds the heart. It has two coats:
- the outter coat-parietal pericardium
- the inner coat-visceral pericardium or epicardium which is double-layered and contains pericardial fluid between those two layers (pericardial fluid is necessary as a lubricant for the heart movement).
Besides lubrication, percardium also protects heart from infections, fixes it and limits its movements.
Answer: Haploid number
In normal humans, sex cells contain the diploid number of chromosomes
Explanation;
Human somatic cells or body cells are diploid such that they contain two sets of 23 chromosomes which gives a total of 23 chromosomes. Examples of somatic cells in the body that are diploid include, epithelial cells, somatic cells, liver cells, blood cells, nerve cells, etc.
However, mature sex cells are haploid, which means they have one set of 23 chromosomes which means they have 23 chromosomes. Sex cells are the results of meiosis type of cell division in which a diploid cell divides to form four daughter cells that are haploid.
The right atrium receives the de-oxygenated blood from the body. From the right atrium blood passes to the right ventricle.
The right ventricle propels this de-oxygenated blood to the lungs though pulmonary artery, for oxygenation. The deoxygenated blood loses carbon-di-oxide and gains oxygen in the lungs. This process is called gaseous exchange.
After the gaseous exchange, blood becomes oxygenated. This oxygenated blood comes to left atrium of the heart through pulmonary veins.
From the left atrium blood comes to the left ventricle. Left ventricle sends this oxygenated blood through aorta and arteries to all organs of the body.
