In a process called diffusion, oxygen moves from the alveoli to the blood through the capillaries (tiny blood vessels) lining the alveolar walls. Once in the bloodstream, oxygen gets picked up by the hemoglobin in red blood cells.
The sequence of impulse through the cardiac conduction system starts from SA node passes to AV node to atrioventricular bundle fibers and finally to Purkinje fibers.
Heart is an organ that receives oxygenated blood form lungs and deoxygenated blood from different parts of body. Oxygenated blood is transported to different organs and deoxygenated blood is transported to lungs for oxygenation.
Now, to perform this transportation, the auricles and ventricles of heart contract and relax. In order to contract and relax, impulse generation is required, which begins at SA node or Sinoatrial node. It is also referred to as pacemaker of the heart. SA node contracts the atria and the impulse transfers to AV node or Atrioventricular node.
This is followed by transfer of impulse to atrioventricular bundle fibers which further passes it on to Purkinje fibres for ventricular contraction. Now the blood is sent to lungs and aorta as per it's oxygen status.
Learn more about cardiac conduction system -
brainly.com/question/2813924
#SPJ4
Answer:
D. A mutation causing uncontrolled cell division
Explanation:
Cell division is controlled by various mechanisms. Any mutations in the genes regulating the cell division lead to uncontrolled cell division. Loss of control over the process of cell division leads to the formation of tumors.
These tumors may cause cancer if they are transformed into malignant tumors. Hence, a mutation that causes loss of control over cell division is harmful.
In general, the process responsible for the growth and repair of human tissue is the healing process, which takes place in three phases.
1. inflammatory response. Injured tissues release chemicals that draw resources to the area, alert the body that damage has occurred and inhibit function to prevent further injury.
2. Repair phase. Once injured area is walled off and debris removed, construction to replace or repair injured tissue begins. New blood vessels grow in the injured area maximizing transport within tissue.
3. Remodeling phase. Construction of permanent tissue , typically strong scar tissue made from dense network of collagen fibers.
Looking at it from cell level, the process of mitosis is actually taking place during healing.
Mitosis is used for growth and repair and produces diploid cells identical to each other and to the parent cell.
New cells are needed throughout life. These are for growth and replacement of damaged or worn out tissue. The body obtains such through the process of mitosis.
