Organization of the Human Body Anatomy & Physiology Chapter 1

Anatomy Anatomy is the study of the structures and shape of the body and body parts and their relationship to each other. Study of the large body structures is called gross anatomy. Study of the small body structures is called microscopic anatomy.

Physiology Physiology is the study of how the body and its parts function. Physiology has many subdivisions include: Neurophysiology – functions of the brain Cardiac Physiology – functions of the heart

Plan of the Human Body There are several levels of organization in the human body. The levels range from simple to more complex. Levels of Organization are: Atoms > Cellular > Tissue > Organ > Organ System > Organism

Specialization of Cells The process by which cells of a common origin specialize to perform specific functions is called differentiation. Cells with a common origin, appearance and function are called tissues. The body consists of four types of tissue: epithelial, connective, muscular, and nervous.

Functions of Different Types of Tissue Epithelial tissue covers and protects surfaces. Connective tissue joins various parts together and provides support. Muscular tissue allows movement. Nervous tissue responds to environmental stimuli and coordinates bodily activity.

Organ Systems An organ is formed when two or more types of tissues join together to perform a specific function. When organs join together, they form an organ system. The organ systems all working together form an organism.

Survival Needs of the Body To survive, the body has certain needs: Nutrients – contain the chemicals used for energy and cell building and are taken in through digestion Oxygen – a chemical that is required to process and digest food to supply energy to the body Water – the most abundant substance in the body which is required for all reactions & transport Body temperature – cells can only survive within a certain temperature that is maintained by chemical reactions within the body Atmospheric pressure – required to move oxygen in and carbon dioxide out of the lungs

Life Functions Organ systems work together to promote the well being of the body. The functions organ systems provide include: Maintaining boundaries –Integumentary system Movement – Muscular and skeletal systems Responsiveness – Nervous system Digestion – Digestive system Metabolism – Digestive, Respiratory and Circulatory systems Excretion – Excretory and Lymphatic system Reproduction – Reproductive system Growth – Endocrine system

Organ Systems Match the human organ systems with their functions: Integumentary – external covering of the body Skeletal – bones, cartilages, ligaments, and joints Muscular – muscles of the body Nervous – body’s control system Endocrine – hormonal system of the body Cardiovascular –heart and blood vessels Lymphatic – lymph tissues of the body Respiratory –oxygen & carbon dioxide exchange system Digestive – system for processing food Urinary – system for ridding the body of waste Reproductive – system for producing offspring

Homeostasis Homeostasis is the body’s ability to maintain relatively stable conditions. Every organ system plays a role in maintaining homeostasis to keep the body healthy. Communication within the body is required to maintain homeostasis.

Homeostatic Mechanisms The nervous system and endocrine systems are mostly responsible for maintaining homeostasis. Homeostatic mechanisms have three components: receptor, control center and effector. The receptor is a sensor that monitors and responds to changes in the environment. The control center receives information and then determines a response. An effector provides the means for the control center’s response.

Anatomical References Directional terms are used to describe the location of structures within the body, in anatomical position. Anatomical position is the body standing up with feet parallel and arms at the side with palms facing forward.

Anatomical References Coronal Plane (Frontal or Medial Plane) A vertical plane running from side to side; divides the body or any of its parts into anterior and posterior portions. Sagittal Plane (Lateral Plane) A vertical plane running from front to back; divides the body or any of its parts into right and left sides. Axial Plane (Transverse Plane) A horizontal plane; divides the body or any of its parts into upper and lower parts.

Directional Terms Certain terms are used by medical personnel to describe the body structures in relationship to each other. The following terms are used together: Superior (above) and inferior (below) Anterior (front) and posterior (back) Medial (close to center line) and lateral (away from center line) Proximal (closer to trunk) and distal (farther away from trunk) Superficial (close to surface) and deep

Body Cavities The human body is divided into two major spaces: the dorsal cavity and ventral cavity. Dorsal cavity is divided into the: cranial cavity and spinal cavity. The ventral cavity includes: the thoracic cavity, abdominal cavity and pelvic cavity.