Science 2nd Quarter: Respiratory, Digestive, and Integumentary Systems PDF

INTEGUMENTARY SYSTEM Skin is the largest external organ of the human body, it performs different functions. It acts as an excretory organ, a sense organ, and a temperature regulator. The skin has the receptors that recognize heat, cold, pain, and touch....

INTEGUMENTARY SYSTEM Skin is the largest external organ of the human body, it performs different functions. It acts as an excretory organ, a sense organ, and a temperature regulator. The skin has the receptors that recognize heat, cold, pain, and touch. The human skin has three layers 1. EPIDERMIS – outer layer that is barrier to infections. 2. DERMIS – middle layer that contains nerves hair roots, sweat and oil. 3. HYPODERMIS – fat, blood vessels and connective tissue that helps maintain body temperature. Epidermis- is the outmost layer of the skin. It has pores through which sweat and oil excreted. Its surface consist of dead cells that are continually shed off and replaced by new cells. It also contains melanin which is responsible for your skin color. Melanin shields you from harmful ultraviolet sunlight. DERMIS middle layer of the skin. It is where nerve endings, blood vessels and sweat and oil glands are found. The sweat gland is a coiled tube that secretes sweat. Sweat is a waste product excreted through the pores of the skin. HYPODERMIS The hypodermis is the inner layer of the skin. It is mainly for fat storage that insulates the body to make sure that you stay warm.  DIGESTIVE SYSTEM The digestive system is composed of organs working together to get nutrients from the food we eat. Functions of DIGESTIVE SYSTEM 1. ingestion – the taking in of food and water; 2. digestion – the breaking down of food into smaller molecules; 3. absorption of nutrients; 4. egestion – the removal of waste. Two Kinds Of Digestion 1. MECHANICAL DIGESTION - involves physically breaking the food to smaller pieces. Mechanical digestion begins in the mouth as the food is chewed. It also takes place as the food moves down the digestive tract via peristalsis – is the rhythmic, involuntary contraction of smooth muscles. In chemical digestion, the food particles are broken down into nutrients and other substance that can be absorbed by the body. This starts at the mouth and continuous in the stomach and small intestine. The digestive system has two main divisions: 1. gastrointestinal tract composes of a. mouth and its parts a. pharynx b. esophagus c. stomach d. intestines. 2. accessory digestive organs contain the ff a. liver b. pancreas c. gallbladder. Mouth- - Digestion begins in the mouth with the help of your teeth, tongue and salivary glands. Its main function is to receive food and chew it into pieces. ESOPHAGUS - is a straight muscular tube that transports bolus from the mouth to the stomach. Bolus keeps moving down the stomach through the rhythmic muscular contractions in the esophagus called peristalsis STOMACH- is a J-shaped muscular sac that digests and temporarily stores food. Your stomach secretes gastric juices that contain hydrochloric acid and enzymes that help digest food. SMALL INTESTINE -- is a coiled tube of about 8 m long. This is where the digestion of food will be completed. The breakdown of food in the small intestine takes 4-8 hours. The undigested food then passes to the large intestine LARGE INTESTINE- - is a tube that is shorter but wider than the small intestine. It is about 2 meters long. In the large intestine, water, undigested food and bacteria combine to form the waste materials called feces. LIVER-- the largest internal organ of the body. The main function of this organ is to produce bile to digest fats and neutralize acids GALLBLADDER - stores with bile and acts only on the digestion of fat and stores iron and vitamins. PANCREAS - An elongated organ behind the stomach. It secretes pancreatic juices that help digest carbohydrates, fats and proteins.  RESPIRATORY SYSTEM The respiratory system consists of organs that help you breathe. Breathing - is a process that allows your body to take in oxygen and release carbon dioxide. RESPIRATORY SYSTEM PARTS AND FUNCTIONS NOSE - serves as an entrance of air during inhalation. It has two small openings called nostrils - where gas enters ad leaves the body. Specialized hair called cilia are found inside the nose to trap the dirt in the air.  PHARYNX- is a muscular tube in which food, water and air passes through. A flap tissue called epiglottis prevents food and water entering the larynx. LARYNX- - also called voice box. It contains the vocal cords that vibrate when you talk. The air that comes out from the lungs causes the vocal cords to vibrate. TRACHEA - also called the windpipe. Trachea is a hollow muscular tubular structure. Air passes through the larynx and trachea on its way to the lungs.  BRONCHI - tubes that connect the trachea and the lungs. Each tube called bronchus, leads to lung. The bronchi branch out into tinier tubes called bronchioles. LUNGS - are the main organ of the respiratory system. They are elastic and spongy organs protected by a membrane called pleura. The lungs are made up of tiny air sacs known as alveoli.