Lec1 Introduction To The Human Body PDF

Lec1: INTRODUCTION TO THE HUMAN BODY Prepared by: Roy P. Maribojoc MD MPH Physiology—the study of the functions of living organisms and their parts. Anatomy—the study of the structure of an organism and the relationship of its parts STRUCTURAL LEVELS OF THE BODY Organization is an outstandin...

Lec1: INTRODUCTION TO THE HUMAN BODY Prepared by: Roy P. Maribojoc MD MPH Physiology—the study of the functions of living organisms and their parts. Anatomy—the study of the structure of an organism and the relationship of its parts STRUCTURAL LEVELS OF THE BODY Organization is an outstanding characteristic of the body structure. The body is constructed of the following smaller units: > Chemical level, i.e. atoms The simplest level of organization within the body is the chemical level, which is composed of atoms and molecules. 􀂃 Atoms are the smallest units of matter. > Cells The cell is the smallest structural unit that exhibits the characteristics of living things (organisms), and it is the smallest living portion of the human body. >Tissues Groups of similar cells with a common function > Organs Different tissue types that work together to perform specific, complex functions >Systems Introduction to Body Systems: Our bodies are made up of eleven systems, each of which has been designed to fulfill different functions: Digestive. This is the system that breaks down food and absorbs its nutrients. The digestive tract is a long system of tubes that run from the mouth to the anus. It includes the mouth, pharynx, esophagus, stomach, small intestine, and large intestine. The liver and the pancreas manufacture special enzymes to help break down food. Muscular. This system provides the body with movement. There are three types of muscle: skeletal, cardiac, and smooth. Skeletal muscles attach to bones, and are voluntary--they are consciously controlled by the nervous system. Cardiac muscles cause the heart to pump blood, and are involuntary--they contract automatically. Smooth muscles are also involuntary, and cause movement in other organs; these are the muscles that push the food that we eat down the esophagus and into the stomach. Integumentary. The integumentary system includes skin, which provides sensory receptors and protects the body, and its accessory structures such as hair and 1 nails. Excretory or Urinary. This system gets rid of various body wastes and maintains the fluid and the electrolytes balance in the body. The major organs of this system include the kidneys, ureter, urinary bladder and urethra. Reproductive. The reproductive system allows for the continuation of life. Gametes from the male's sperm and the female's egg combine to form a zygote--a unique combination of genes which no other human being has! Circulatory. Consists of a pump (the heart) that moves blood through blood vessels in order to distribute hormones, nutrients, gases, and pick up waste products Respiratory. The respiratory system provides the body with oxygen, and it expels carbon dioxide from the body. The nasal passage, trachea, bronchial tubes, lungs, and alveoli are involved in this process. Inhaled oxygen is broken down in the alveoli (tiny air sacs in the lungs) and then passed into the capillaries, where it travels into the bloodstream. In the same way, carbon dioxide from the blood is passed back into the alveoli, and exhaled from the body. Skeletal. The skeletal system provides structure for the body, attachment of the muscles, and protection for the body's internal organs Immune. The immune system, which is made up of special cells, proteins, tissues, and organs, defends people against germs and microorganisms every day. In most cases, the immune system does a great job of keeping people healthy and preventing infections. Nervous. The brain, spinal cord, and nerves work together to coordinate the body's actions. Our senses are also part of this system, allowing us to see, taste, smell, touch, hear, and feel pressure and pain. It is also responsible for consciousness, intelligence and memory. Endocrine. The endocrine system is made up of the chemical messengers which control many bodily activities called hormones. Hormones initiate many bodily processes, such as reproduction, growth, and digestion. 2