Human Body Systems PDF

Human Body Systems Digestive System ❑ The body system responsible for extracting nutrients and other useful substance from food. ❑ This system is composed of the digestive tract, also called alimentary canal, and the accessory organs that play important roles in the...

Human Body Systems Digestive System ❑ The body system responsible for extracting nutrients and other useful substance from food. ❑ This system is composed of the digestive tract, also called alimentary canal, and the accessory organs that play important roles in the digestion process.  Type of Digestion □ Mechanical Digestion- there is physical breakdown of food into smaller parts □ Chemical Digestion- starts in the mouth through the action of the enzyme present in the saliva.  Mouth ❖ Is where the process of digestion starts where the food is mechanically digested by the process of chewing or mastication. The teeth tear cut, and grind the food into smaller pieces ❖ There are four types of teeth. The incisors, which have thin edges, are for cutting food. The canines, which are pointed, are for tearing meat. The broader and bigger premolars and molars are for crushing and grinding food. ❖ As the food is being chewed, saliva is released by the salivary glands, moistening the food for easy swallowing. The saliva contains salivary amylase, an enzyme that breaks down starches into smaller sugars  Esophagus ❖ Is a muscular tube that can open and close at the upper end which is connected to pharynx. ❖ The chewed food, referred to as bolus, passes through the pharynx then to the esophagus. ❖ The rhythmic and wavelike contractions of the esophagus, called peristalsis, force and push the bolus down to the stomach  Stomach ❖ Is a hollow muscular organ shaped like a bag. ❖ Its upper end is connected to the esophagus while its lower end is connected to the small intestine  Small Intestine ❖ Is a coiled tube that measures approximately seven meters long. ❖ Being the largest part of the digestive system, it forms loops, as it can fit in the small space of the abdomen. ❖ It is in the small intestine where most of the digestion takes place.  Accessory Digestive Organs ❖ Liver is the largest organ in the body and is located near the stomach. It produces bile which is needed in breaking down fats. ❖ The liver also stores nutrients like iron and copper and releases them once the body needs them. ❖ Gallbladder-is a small sac under the liver where bile is stored. ❖ During digestion, the gallbladder releases bile into small intestine. ❖ Pancreas- is a long elongated organ behind the stomach. ❖ It secretes pancreatic juice which neutralizes the acidity of chyme before it enters the small intestine. ❖ It also has enzymes that help break down proteins and fats in the small intestine.  Large Intestine ❖ Water from the undigested food is absorbed. ❖ The intestinal flora, or bacteria living in the intestines, help break down the food remains until only waste remain. ❖ These wastes will be expelled from the body in the form of feces.  Rectum and Anus ❖ The last section of the digestive tract. ❖ The rectum provides temporary storage for the feces before they are expelled in the body. ❖ As the rectum expands due to the accumulating feces, receptors in the rectal walls stimulate the urge to defecate. ❖ Peristaltic waves then push the feces out of the body through the anus. Respiratory System ❑ It allow the exchange of gases in the body, specifically to bring oxygen to the cells and release carbon dioxide to the environment ❑ It has an upper and lower tract. ❑ The upper tract consist of the nose, nasal cavity and pharynx. ❑ The lower tract consists of the larynx, trachea, bronchial tubes and the lungs.  Nose and Nasal cavity ❖ The nose is the outer part of the respiratory system. ❖ The nose is mostly made of cartilage instead of bone making it flexible but strong. ❖ The two opening of nose, called nostrils, lead to the nasal cavity. ❖ The lining of the nasal cavity is moist because of mucus. ❖ Tiny hairs also line in this cavity. ❖ The hair and mucus filter out the dust and dirt that comes with the inhaled air. ❖ They also warm and moisten the air that enters the body  Pharynx ❖ The back part of the mouth cavity arches and leads to the throat cavity. ❖ It is a tube which acts as a passageway for both air and food. ❖ Both mouth and nasal cavities lead to pharynx. ❖ The tonsils flank the opening of the pharynx.  Larynx ❖ At the lower end of the pharynx is the voice box. ❖ When you talk, the vocal cords in the larynx vibrate, so sound is produced.  Trachea ❖ The trachea or the windpipe, is a tube at the bottom of the larynx. ❖ The wall of the trachea is lined with mucus and cilia. ❖ The cilia prevents dust particles from going into the lungs. ❖ They help in carrying the trapped dust in the mucus back to the throat through coughing and swallowing  Lungs ❖ Its main function is to help oxygen from the air you breathe enter the red cells in the blood. ❖ There are two lungs which are found in the chest on the right and left side. ❖ The pleurae are the protective linings that covers the lungs. ❖ The right lung is slightly larger and heavier than left lung and it has three lobes while the left lung has two lobes. ❖ The trachea divides into two tubes each entering the lung. ❖ These tubes called bronchial tubes branch into smaller tubes called bronchioles. ❖ Each bronchiole end in very tiny air sacs called alveoli. There are about 300 to 600 million alveoli in the lungs. Urinary System ❑ It is responsible for excreting most of the liquid wastes from the body. ❑ Excretion- is the process by which the body gets rids of wastes produced by its cells.  Kidneys ❖ Main organs of the urinary system. ❖ They are two bean-shaped organs found at the lower part of the spinal column, one on each side. ❖ They filter all the blood in the body about 300 times each day. ❖ They clean the blood, remove the waste substances and ensure that only useful substances stay in the blood circulation. ❖ Eliminates excess water, urea, excess salts and other wastes from the blood. ❖ Maintain balance of water and salts in the body. ❖ Each kidneys has two parts, the outer layer called cortex, and the inner layer called the medulla. ❖ Filtration units are found within the cortex while the medulla is made up of collecting tubules through which the urine passes down to the ureters. ❖ Nephrons-purify the blood and remove the wastes.  Ureters ❖ The urine flows out from the kidneys to the bladder through the two ureters. ❖ The smooth muscles of the ureters move by peristalsis to move the urine towards the bladder.  Bladder ❖ The urinary bladder is a hollow muscular organ that acts as temporary storage for urine.  Urethra ❖ Urine is emptied from the bladder and leaves through the urethra. ❖ The urethra is a tube at the bottom of the bladder. ❖ The length of the urethra varies in male and female. The female urethra is about 4 centimeters long while the male is about 9 centimeters long. ❖ The urethra has a sphincter muscle which serve as a valvelike structure to help regulate the outflow of urine. ❖ Urination is the process of eliminating urine.