Organization of the Body Chapter 4 Organization of the Body

Identify parts of a cell and the specialized functions of tissues Identify the body systems Describe the functions of the body system and how they work Define the anatomical positions of the body List the body cavities and the organs Identify nine body regions

Organization of the Human Body The body is organized from the smallest part to the largest part. CELL -simplest structural unit -basic unit of life -smallest unit that can live on its own

Cell Many cannot be seen with the naked eye A cell may be an entire organism or it may be one of billions of cells that make up the organism

Tissue - a group of cells with common origin, structure, and function. - cells within a tissue all work toward a common goal (i.e.: movement, nutrition, etc.) Organ - a group of tissues that have a common function.

Structural units of the body: Cell: Body has million of cells that work together to sustain life consist of a nucleus surrounded by cytoplasm It is the fundamental unit of all living things (basic building block) Cells multiply by dividing called mitosis

Contd: Several types of cells Size and shape of cell relates its function Examples of some cells in the body: Muscle cells: contract Nerve: conduct electrical impulses Epithelial: skin and lining Fat cell: contain empty spaces to store fat

Nucleus A spheroid body within a cell Consists of a thin nuclear membrane and genes and chromosomes Responsible for metabolism, growth and reproduction Control center of the cell

Chromosomes Thread like structures in the cell nucleus Control growth and repair Control the reproduction of the body Contain regions of DNA called genes There are 23 pairs of chromosomes in every cell except for the egg and sperm which contain 23 unpaired chromosomes

Cytoplasm The substance between the cell membrane and the nuclear membrane Jelly like material that is mostly water It is exclusive to the nucleus Carries on the work of the cell

Cell membrane Thin layer of tissue which serves as the wall of the cell Protects the cell Selectively allows substances to pass in and out of the cell

Tissues: groups of similar cells working together to do a specific job For example: Muscle tissue contracts Epithelial tissue forms linings and covers i.e. skin Connective tissue do just that: fat, cartilage, bone and blood Nerve tissues conduct impulses all over the body

Tissue Epithelial tissues The skin and lining surfaces Forms the lining of the internal organs It protects, absorbs and excretes

Connective tissue The fibrous tissue of the body Binds together the various parts and organs of the body Eg: bones , tendons cartilage

Muscle tissue Tissue that contracts Consist of striated (striped) cardiac and smooth muscle Voluntary is where the movement is under conscious control such as arms and legs Involuntary is not under conscious control, such as heart and digestive system

Nerve Tissue A collection of nerve fibers that conduct impulses that control and coordinate body activities

Organ System - a group of organs with a special function. - Digestive System, Nervous System, etc… Organism - A group of organ systems that at some point in time is capable of sustaining life. - All organ systems work together in an organism.

Organs: structures composed of several types of tissue An organ (Latin: organum, "instrument, tool") is a group of tissues that perform a specific function or group of functions. Usually there is a main tissue and sporadic tissues. The main tissue is the one that is unique for the specific organ. For example, main tissue in the heart is the myocardium, while sporadic are the nervous, blood, connective etc.

A set of body organs that work together for a common purpose Systems: A set of body organs that work together for a common purpose

systems Integumentary system Musculoskeletal system Cardiovascular system Gastrointestinal system Respiratory system Genitourinary system Endocrine system’ Nervous system

Body Cavity: space within the body that contains internal organs The human body consists of the following cavities: dorsal body cavity cranial cavity, enclosed by the Skull and contains the brain, eyes, and ears. spinal canal, enclosed by the spine and contains the spinal cord. ventral body cavity thoracic cavity, enclosed by the ribcage and contains the lungs and heart. abdominopelvic cavity abdominal cavity, enclosed by the ribcage and pelvis and contains the kidneys, ureters, stomach, intestines, liver, gallbladder, and pancreas./pelvic cavity, enclosed by the pelvis and contains bladder, anus and reproductive system.

Body cavities and Planes The body has two main large cavities Ventral = front of body includes thoracic, abdominal, and pelvic cavity Dorsal = back of body which includes Cranial and Spinal cavity

Anatomical Planes Fixed lines of reference along which the body is often divided or sectioned to facilitate viewing of its structures Allow one to obtain a three-dimensional perspective by studying the body from different views

Sagittal A plane that divides the body into right and left portions Midsagittal A plane that vertically divides the body or some part of it, into equal right and left portions

Coronal Also called frontal; a plane that divides the body into anterior and posterior sections (front and back) Transverse A plane that divides the body into superior and inferior sections (top and bottom)

Anatomical Position Standing erect, with palms and feet facing forward Is the standard reference point in which all positions, movements, and planes are described

Positions and Directions Terms of position and direction describe the position of one body part relative to another, usually along one of the three major body planes

Positions and Directions Superior Refers to a structure being closer to the head or higher than another structure in the body Inferior Refers to a structure being closer to the feet or lower than another structure in the body

Positions and Directions Anterior Refers to a structure being more in front than another structure in the body Posterior Refers to a structure being more in back than another structure in the body

Positions and Directions Medial Refers to a structure being closer to the midline or median plane of the body than another structure of the body Lateral Refers to a structure being farther away from the midline than another structure of the body

Positions and Directions Distal Refers to a structure being further away from the root of the limb than another structure in the limb Proximal Refers to a structure being closer to the root of the limb than another structure in that limb Root Root