Body Organization and Terminology

Introduction Anatomy –The study of the form and structure of an organism. Physiology – The study of the processes of living organisms, or why and how they work. Pathophysiology –Study of how disease occurs and response of the body to disease process.

Homeostasis Definition: A constant state of natural balance within the body. –Example: if you become too hot a message is sent to your brain, your brain reacts by making adjustments causing you to sweat, and your blood vessels near the skin to dilate, these things cause you to cool off, now your body must send your brain a new message, it again reacts by stopping the sweating and dilation. Homeostasis allows the body to regulate itself in many ways, blood glucose levels, temperature, and heart rate are just a few.

Tissues

Tissue Cells of the same type join together for a common purpose. 60 – 99% water with various substances dissolved in it. –Fluid called tissue fluid –Slightly salty in nature –Dehydration: insufficient amount of tissue fluid –Edema: Excess amount of tissue fluid; swelling

Four Groups of Tissues Epithelial Connective Nerve Muscle

Epithelial Tissue Covers surface of body and main tissue in skin. Forms lining of intestinal, respiratory, circulatory, and urinary tract and body cavities. Forms body glands where it specializes to produce specific secretions for the body.

Connective Tissue Supporting fabric of organs and other body parts. Soft connective tissue –Adipose or fatty tissue: stores fat as a reserve food source of energy, insulates the body, and acts as padding

Connective cont. –Fibrous connective tissue: includes ligaments and tendons that help hold body structures together.

Connective cont. Hard connective Tissue –Cartilage: tough, elastic material found between bones of spine and at end of long bones where it acts a s a shock absorber and allows for flexibility; also found in nose, ears, and larynx to provide form.

Connective cont. Bone: similar to cartilage but has calcium salts, nerves and blood vessels; frequently called osseous tissue; helps form body structure

Connective cont. Blood and lymph classified as liquid connective tissue or vascular tissue. –Blood carries nutrients and oxygen to body cells and metabolic wastes away from cells. –Lymph transports tissue fluid, proteins, fats, and other materials from the tissues to the circulatory system

Nerve Tissue Made of special cells called neurons Controls and coordinates body activities by transmitting messages throughout the body. Nerves, brain and spinal cord are composed of nerve tissue

Muscle Tissue Produces power and movement by contraction of muscle fibers Three main types –Skeletal: attaches to bones and provides movement.

–Cardiac: causes heart to beat

–Visceral (smooth): in walls of the respiratory, digestive, urinary tract and blood vessels

Organs

Two or more tissues join together for a specific function. Examples include heart, stomach, and lungs.

Systems Organs and other parts that join together for a particular function. Includes integumentary, skeletal, muscular, circulatory, lymphatic, nervous, respiratory, digestive, urinary or excretory, endocrine and reproductive.

Body Planes Imaginary Lines drawn through the body at various parts to separate the body into sections. Directional terms are created by these planes.

Transverse plane One of the three main planes. Horizontal plane. Divides body into top and bottom half. Superior: body parts above other parts. Inferior: body parts below other parts. Example: Knee is superior to ankle but inferior to hip. Cranial: body parts located near the head. Caudal: body parts located near the sacral region of the spinal column or “tail”.

Midsagittal or Median Plane Second plane of body Divides body into right and left sides. Medial: body parts close to midline or plane. Lateral: body parts away from midline or plane.

Frontal or Coronal Plane Third plane of the body. Divides the body into front and back section. Ventral or anterior: body parts in front of the plane or on the front of the body. Dorsal or Posterior: body parts on the back of the body or behind the plane.

Proximal and Distal Used to describe the relationship of the extremities to the main trunk of the body, generally called the point of reference. Proximal: body parts close to the point of reference. Distal: body parts away from the point of reference. Example: wrist is distal to and elbow is proximal to the shoulder or point of reference.

Body Cavities Spaces within the body that contain vital organs. Dorsal or Posterior cavity –One of two main cavities –One long continuous cavity on the back of the body. –Divided into two sections: Cranial cavity: contains the brain. Spinal Cavity: contains the spinal cord.

Ventral or anterior cavity –Larger than dorsal cavity –Separated into two distinct cavities by diaphragm. –Thoracic cavity Located in chest Contains esophagus, trachea, bronchi, lungs, heart and large blood vessels. –Abdominal or Abdomino-pelvic cavity. Divided into upper and lower part. Upper abdominal cavity contains: stomach, small intestines, most of large intestine, appendix, liver, gallbladder, pancreas and spleen. Lower abdominal or pelvic cavity contains: urinary bladder, reproductive organs, and last part of large intestine.

Three Small Cavities Orbital for the eyes. Nasal for the nose structures. Buccal or mouth cavity for the teeth and tongue.

Abdominal Regions Abdominal cavity separated into regions or sections because it is so large. Quadrants –One method of division. –Creates right upper quadrant (RUQ), left upper quadrant (LUQ), right lower quadrant (RLQ), and left lower quadrant (LLQ)

Regions Epigastric: upper center region above the stomach. Umbilical: middle center region by umbilicus. Hypogastric or pelvic: Lower center. Hypochondriac: on either side below the ribs. Lumbar: on either side by large bones of spinal cord. Iliac or inguinal: on either side by groin.