Biology - Human Respiratory System

A. Figure of human respiratory system

B. Inhale and exhale mechanism

Inhalation:

On inhalation the diaphragm contracts and becomes flatter as it is lowered. In addition, the lower ribs swing upwards and outwards as the external intercostal muscles contract. These movements increase the volume of the thorax and the pressure within it falls to below atmospheric pressure. Consequently, air rushes into the lungs to fill this partial vacuum.

Exhalation:

Relaxation of the external intercostals and the diaphragm allow a set of opposing muscles, the internal intercostal muscles, to return the thorax to its previous size. As the thorax diminishes in size air is expelled from the lungs. All English speech sounds are composed using exhaled air from the lungs, i.e. using a pulmonic air stream.

C. Effect of carbon monoxide from smoking a cigarette on human body  

Carbon monoxide binds to hemoglobin in red blood cells, preventing affected cells from carrying a full load of oxygen.

D. Chemicals in Cigarettes

1. Carsinogens : benzene, formaldehyde, pesticides, TSNAs, and vinyl chloride.

2. Toxic metals : arsenic, and cadmium.

3. Radioactive toxic metals : radioactive cigarette smoke.

4. Poisons : ammonia, carbon monoxide, hydrogen cyanide, and nicotine.

 

 

 

Biology - Small Intestine

Small bowel or small intestine is the part of the digestive tract that lies between the stomach and the colon. In the duodenum, there are two estuaries, intestinal tract is a continuation of the stomach. The small intestine consists of three parts, namely the duodenum (duodenal), empty intestine (jejunum), and intestinal absorption (ileum). Intestine has a length of about 6-8 meters. The small intestine is divided into 3 parts: the duodenum (± 25 cm), jejunum (± 2.5 m), and ileum (± 3.6 m). In the small intestine occurs only chemical digestion alone, with the help of a chemical compound produced by the small intestine as well as chemical compounds that are released from the pancreas to the small intestine.

Substance produced by the small intestine are:

1. Bile
2. Pancreatic Juice