Part 1: Respiratory System

Describe how air passes into the lungs. What structures does it pass through? Describe the anatomy and how those structures contribute to the system. Where does gas exchange occur? Make sure you mention all of the structures that air passes through, beginning at the nose and ending in the alveoli.

Part 2: Blood Flow Through the Heart

Describe the flow of blood through the heart and name each of the chambers and vessels that the blood circulates through. Make sure to discuss the structures in the order in which blood flows through them. Don't forget to also mention the valves that the blood flows through. Include a discussion of the systemic and pulmonary circulations.

 

Respiratory system.

When inhalation occurs, air enters the lungs and oxygen in the air enters the blood stream. When you inhale through the nose, air travels down the pharynx then to the larynx and into the trachea which is also called windpipe. One bronchial tube leads to the left lung and the other to the right lung.

The upper airway include nose which is an opening which makes it possible for air to enter the body, the larynx and trachea before entering the lung. These structures act to funnel fresh air down from the outside world into the body. Air can also enter the body through the mouth cavity.

The lungs are paired, cone-shaped organs which take up the most the most space i the chest. Everybody has two lungs. the right lung has three lobes but the left lung has only two. The lungs is divided into seven smaller portions called Broncho pulmonary segments which pyramidal-shaped areas separated from each other by membranes.

Air enters the lungs through a system of pipes called bronchi. These pipes start from the bottom of the trachea as the left and right bronchi and branch into respiratory bronchioles many times in the lung to form thin-walled air sacs or bubbles called alveoli. In the alveoli is where gaseous exchange takes place between air and the blood. Covering each alveolus is a whole network of blood vessel called capillaries which are very small branches of the of the pulmonary arteries. Oxygen which is more in the alveoli travels across the the walls of the alveoli into the blood stream. Carbon (iv) oxide travels opposite to oxygen into the alveoli then exhaled to the outside.

Blood flow through the heart.

Blood enters the heart through the inferior and superior vena cava, emptying oxygen-poor blood from the body into the right atrium of the heart.

As the atrium contracts, blood flows from your right atrium into your right ventricle through the open tricuspid valve. When the ventricle is full, the tricuspid valve shuts. This prevents blood from flowing backward into the atria while the ventricle contracts.

• As the ventricle contracts, blood leaves the heart through the pulmonic valve, into the pulmonary artery and to the lungs where it is oxygenated. Pulmonary vein carries oxygen rich blood from the lung into the left atrium of the heart and with the contraction of the atrium, the blood flows through the mitral valve which is open to left ventricle. Then mitral valve shuts when the left ventricle is full to prevent backflow of blood into the atrium. The ventricle contracts and oxygen enriched blood leaves the heart through the aortic valve into the aorta then to the arteries. The blood in the arteries then reaches the body organs to enable the systems like the digestion system to work properly. The blood then enters the capillaries then to veins back to the heart through venacava.