Chapter 1 The Human Body: An Orientation Human Anatomy Chapter 1 The Human Body: An Orientation

I. Definitions Anatomy is the study of the structure and shape of the body and body parts and their relationships to one another. Gross anatomy – examining large easily observable body structures. Microscope anatomy – examining cells and tissues using a microscope.

I. Definitions (con’t) Physiology is the study of how the body and its parts work or function. Neurophysiology – explains how the nervous system works. Cardiac physiology studies the functions of the heart. Anatomy and physiology are always related. FORM FOLLOWS FUNCTION.

II. Levels of Organization Atoms – building blocks of matter. They combine to form: Molecules – water, sugars, and proteins. Molecules associate in specific ways to form cells.

II. Levels of Organization (Con’t) Cells are the smallest units of all living things. Cells that are similar and have a common function are called tissues. An organ is a structure, composed of two or more tissue types, that performs a specific function for the body. A group of organs that cooperate to accomplish a common purpose is called an organ system. All 11 organ systems make up an organism.

II. Levels of Organization

Integumentary System External covering of the body Waterproofs, cushions and protects Excretes salts and urea in sweat and helps regulate body temperature Sense organ – pain and pressure

Skeletal System Bone, cartilage, ligaments, and joints Support and protection Attachment of the skeletal muscles Hematopoiesis – the formation of blood cells Store house of minerals

Muscular System Only one function – contract Movement occurs when muscles contract Three types of muscle tissue Skeletal muscles - movement Cardial muscles - heart contraction Smooth muscles – intestines, internal organs

Nervous System Fast-acting control system Consists of the brain, spinal cord, nerves, and sensory receptors. The body must be able to respond to stimuli. The Central Nervous system assesses the information received and responds.

Endocrine System Slow acting control system of the body. Produces and releases hormones into the blood. Includes pituitary, thyroid, adrenals, thymus, pancreas, pineal, ovaries, testes, and parathyroid glands.

Cardiovascular System Made up of the heart and blood vessels. Blood is the transporting fluid Carries oxygen, nutrients, hormones, and other substances to and from the cells where waste is exchanged and removed.

Lymphatic System Closely related to the cardiovascular system. Includes lymphatic vessels, lymph nodes, and other organs like the spleen and tonsils. Fluid leaks from the blood vessels and this system returns the fluid back to the circulatory system. Lymph nodes help cleanse the blood and house the cells involved in immunity.

Respiratory System Keep the body constantly supplied with oxygen and remove carbon dioxide. Includes nasal passages, pharynx, larynx, trachea, bronchi, and lungs. Lungs have tiny air sacs in which gas exchange occurs

Digestive System Tube within a tube system running from the mouth to the anus. Includes the oral cavity (mouth), esophagus, stomach, small and large intestines, and the rectum. Break down food into usable macromolecules. Large intestines job is to reclaim water.

Urinary System The body produces waste which must be removed. Nitrogenous wastes (urea and uric acid) must be removed. Sometimes called the excretory system Includes kidneys, ureters, bladder, and urethra. Maintains body’s water and salt balance

Reproductive System Produce offspring Sperm produced by testes Eggs produced by ovaries Fertilization occurs when sperm is deposited into the female by the penis.

HOMEOSTASIS The key to understanding the interactions of the body systems as well as disease and wellness is understanding homeostasis. Homeostasis is the body’s ability to maintain relatively stable internal conditions even though the outside world is continuously changing.

The Language of Anatomy To accurately describe body parts and position we have to have a reference point that is accepted universally. This is helpful when the coroner finds a body and must describe the body. Anatomical position – The assumption that the body is erect with the feet parallel and the arms hanging at the sides with the palms facing forward.

Directional Terms (pg. 12) Superior/cranial/cephalad Toward the head or upper part of the body or structure; above Inferior (caudal) Away from the head end or toward the lower part of a body or structure; below Anterior (ventral) Toward the front of the body (belly) Posterior (dorsal) Toward the back of the body; behind Medial Toward or at the midline of the body; on the inner side of Lateral Away from the midline of the body; on the outer side of Intermediate Between a medial and lateral structure

Directional Terms (pg. 12) Proximal Close to the origin of the body part or the point of attachment of a limb to the body trunk Distal Farther from the origin of a body part or the point of attachment of a lumb to the body truck Superficial Toward or at the body surface Deep Away from the body surface; more internal

Anterior Body Landmarks (pg. 13) Abdominal Anterior body trunk inferior to the ribs Antecubital Anterior surface of the elbow Axillary Armpit Brachial Arm Buccal Cheek area Carpal Wrist Cervical Neck region

Anterior Body Landmarks (pg 13) Digital Fingers and toes Femoral Thigh Inguinal Area where thigh meets the trunk Nasal Nose area Oral Mouth Orbital Eye area Patellar Anterior knee

Anterior Body Landmarks (pg 13) Peroneal Lateral part of the leg Pubic Genital region Sternal Breasbone area Tarsal Ankle region Thoracic Chest Umbilical Navel

Posterior Body Landmarks (pg 13) Cephalic Head Deltoid Curve of the shoulder Gluteal Butt Lumbar Lower back Occipital Posterior surface of the head Popliteal Posterior knee area Scapular Shoulder blade region Sural The area of the calf muscle Vertebral Area of the spine

Body Planes (pg 14) Body planes and sections can be used to describe either the entire body or any part of the body such as an organ. There are several ways to “cut” body. Sagittal section – cut down the middle to create left and right sides. (aka midsagittal or median section if the cut makes equal sides) Frontal or coronal section – a cut that divides the body into anterior and posterior sides. Transverse or cross sections – A cut is made along the horizontal plane dividing the body into superior and inferior parts. Oblique section-B/W transverse and sagittal OR between a transverse plane and a frontal plane.