Human Body Systems Varad Mahajan

Circulatory System Transports blood throughout body Blood is carried through arteries and veins Oxygen rich blood exits the left side of heart and enters the aorta (the largest artery) Blood delivers nutrients and oxygen to cells as it enters the capillaries (the smallest blood vessels) Blood then takes in carbon dioxide, water, and waste Goes back to heart through veins Heart pumps blood to lungs which eliminate carbon dioxide Circulatory System

Breaks food down into protein, vitamins, minerals, carbohydrates, and fats Food travels through esophagus and into stomach after being chewed and swallowed Food is broken down further by stomach acids Food travels to small intestine where it is broken down into nutrients Food enters large intestine where epithelial cells are renewed All the organs from the esophagus to the large intestine are called the gastrointestinal (GI) tract Excess food is turned into waste and eliminated from body Digestive System

Parts of Intestines Small Intestine Duodenum – First section of small intestine. Shortest part of small intestine Jejunum – Middle section of small intestine Ileum – Final section of small intestine. Separated from cecum by the ileocecal valve (ICV) Large Intestine Cecum – Beginning of large intestine. Connected to appendix Colon – Extracts water and salt from solid wastes before they’re eliminated from the body. Divided into 4 smaller parts (ascending colon, transverse colon, descending colon, and sigmoid colon Rectum – Final straight portion of large intestine Parts of Intestines

A group of glands which produce hormones which are released into the bloodstream Hormones are chemicals which control body functions such as metabolism and growth Includes hypothalamus, pituitary gland, pineal gland, thyroid gland, parathyroid glands, adrenal glands, pancreas, gonads, and the thymus Endocrine System

Immune System Body’s defense against infections and diseases Organs, tissues, cells, and cell products respond to viruses and bacteria 3 Types of Responses Anatomic Response – Physically prevents threatening substances from entering the body. An example is the skin Inflammatory Response – Begins attack when anatomic response fails. Excretes substances from body. Examples are sneezing, runny noses, and fever Immune Response – Begins attack when inflammatory response fails. Made up of white blood cells and is the central part of immune system. A quarter of the white blood cells migrate to the lymph nodes and produce antibodies which fight disease Immune System

Lymphatic System Defense mechanism for body like immune system Produces white blood cells and filters out substances that cause disease Generates antibodies Distributes fluids and nutrients in the body Drains excess fluids and protein so tissues don’t swell up Made up of a network of vessels that circulate body fluids Vessels carry excess fluid away from space between tissues and organisms and return to bloodstream Lymphatic System

Made up of tissues that control the movement of the body with help from skeletal system Involuntary muscles are controlled automatically by the nervous system and hormones. 3 Types of Muscle Tissue Skeletal Muscle – Help body move. Voluntary Smooth Muscle – Located inside organs. Involuntary Cardiac Muscle – Found only in the heart. Involuntary Muscular System

Nervous System Made up of brain, spinal cord, and nerves Body’s control system Sends, receives, and interprets nerve impulses throughout the body Central Nervous System – Includes brain and spinal cord. Sends out nerve impulses and analyzes information from the sense organs Peripheral Nervous System – Includes craniospinal nerves that branch off from the spinal cord and brain. Carries nerve impulses from the central nervous system to muscles and glands Autonomic Nervous System – Regulates involuntary actions including heart beat and digestion Nervous System

Reproductive System System of sex organs Sperm from the male fertilizes the female’s egg, or ovum, in the fallopian tube Fertilized egg travels to the uterus Fetus develops in the uterus over a period of nine months Reproductive System

Respiratory System Brings air into body and removes carbon dioxide Includes the nose, trachea, and lungs After air enters the nose or mouth, it goes down the trachea Trachea branches off into two bronchial tubes which go to the lungs These tubes branch off into smaller tubes called bronchioles These end in the alveoli or air sacks Oxygen follows this path to enter the bloodstream At the same time, carbon dioxide passes through the lungs and is exhaled Respiratory System

Skeletal System Made up of bones, ligaments, and tendons Shapes the body and protects vital organs Works with muscular system to make the body move Marrow, a soft, fatty tissue inside bones, creates red and white blood cells Made of 206 individual bones Divided into Two Divisions Axial Skelton – Runs along the body’s midline axis and is made up of 80 bones Appendicular Skelton – Made up of 126 bones in the upper and lower limbs, pelvic girdle, and pectoral girdle Skeletal System

Long Bones – Longer than they are wide and a major bone in the limbs Long Bones – Longer than they are wide and a major bone in the limbs. Grow more than the other throughout childhood. Contain a medullary cavity in the center for bone marrow. Examples are the femur, tibia, and fibula Flat Bones – Vary greatly in size and shape and are very thin in one direction. No medullary cavity. Short Bones – About as long as they are wide. Often cubed or round shaped. Irregular Bones – Have a shape that doesn’t fit the pattern of the other classes of bones. Examples are the vertebrate and sacrum Sesamoid Bones – Formed after birth inside of tendons that run across joints. Grow to protect the tendons. The patella and pisiform bones are the only ones that are counted in the 206 bones that are in the body. Others can form in the joints, but they are not present in all people. Types of Bones

Urinary System Eliminates waste products from the body Kidneys remove waste from the blood and waste combines with water to form urine Urine travels down two thin tubes called ureters to the bladder When the bladder is full, urine is excreted through the urethra Urinary System

The End