Organization and Regulation of Body Systems Chapter 4 Organization and Regulation of Body Systems

Biological Organization In living organisms there are biological levels of organization. Molecules or compounds form Cells the basic units of structure and function in living things. Similar cells working together form Tissues. Several types of tissues that work together form Organs. Several organs that work together form Organ Systems.

Types of Tissues A tissue is composed of specialized cells of the same type that perform a common function in the body. Tissues are Categorized into 4 Major Groups: Connective Muscular Nervous Epithelial

Fibrous, Supportive, and Fluid 1. Connective Tissue Connective tissue binds and supports body parts. Examples: Tendons, Ligaments, Cartilage, Bone, Blood, and Lymph. These examples are classified as different types of connective tissue. There are three main types of connective tissue that will be covered in later Chapters. Fibrous, Supportive, and Fluid

2. Muscular Tissue Muscular tissue moves the body and its parts. There are 3 types of muscular tissue in humans that will be covered in later Chapters. Skeletal Smooth Cardiac

3. Nervous Tissue Nervous tissue allows for communication between cells. Made of 2 major cell types. Neurons Neuroglia

4. Epithelial Tissue Epithelial tissue consists of tightly packed cells forming a continuous layer. Epithelium covers body surfaces and lines body cavities. The usual function of this tissue is protection. When modified it can also carry out: Secretion, absorption, excretion, and filtration.

Epithelium can be classified according to the shape of its cells. Epithelial Tissue Epithelium can be classified according to the shape of its cells. Squamous is composed of irregular shaped flattened cells Cuboidal consists of cube-shaped cells Columnar resembles rectangular pillars or column-shaped cells.

Epithelial Tissue

Epithelial Tissue - Squamous

Epithelial Tissue - Cuboidal

Epithelial Tissue - Columnar

The Integumentary System The integumentary system, or skin, is an example of an organ system. It includes the skin and accessory organs. The skin is an organ that is comprised of all four tissue types. 14141414

What are the functions of the integumentary system? It protects the body from physical trauma, invasion by pathogens, and water loss. It helps regulate body temperature. It allows us to be aware of our surroundings through sensory receptors. It synthesizes chemicals such as melanin and vitamin D.

The Integumentary System Regions of the skin: The skin has 2 main regions called the epidermis and the dermis. Under the skin there is a subcutaneous layer between the dermis and internal structures where fat is stored. It is important for maintaining homeostasis.

Regions of the Skin: The Epidermis The epidermis is the thin outermost layer and is made up of squamous epithelium. The outer layer is dead cells hardened with keratin a waterproofing protein. Deep in the epidermis are special cells called melanocytes that produce melanin. This is the pigment responsible for skin color and protection from UV light. Some cells use the UV light to convert cholesterol to Vitamin D.

Regions of the Skin: The Dermis The dermis is the thick, inner layer of the skin. This is a region of dense fibrous connective tissue, made up of collagen and elastic fibers, which maintain skin tension and prevent tearing. The dermis is where blood vessels, glands and the sensory receptors for touch, pressure, pain, hot and cold are found.

The Integumentary System The Subcutaneous layer: This layer below the dermis is not actually part of the skin. It is composed of connective tissue and fat. This layer insulates the body and provides protection.

What are the accessory organs of the skin and why are they important? The skin has several accessory organs including the nails, hair, oil glands, and sweat glands. Nails are derived from the epidermis and offer a protective covering. Hair follicles are derived from the dermis, but hair grows from epidermal cells. Oil glands are associated with hair and produce sebum that lubricates the hair and skin and retards bacterial growth. Sweat glands are derived from the dermis and help to regulate body temperature.

Organ Systems of the Human Body Organ systems are composed of two or more different organs that work together to provide a common function.   There are 11 major organ systems in the human body.

Complete the following organ system chart for review, identifying some common major organs in each system and roles (functions) of each system.

What are the organ systems of the human body?

What are the organ systems of the human body?

The human body is divided into cavities Body Cavities The human body is divided into cavities Ventral cavity (front) divided into three parts. Thoracic cavity Abdominal cavity Pelvic cavity Dorsal cavity (back) divided into two parts. Cranial cavity Vertebral cavity

Body Cavities

Homeostasis Homeostasis is the ability to maintain a relative constancy of the body’s internal environment by adjusting its physiological processes. Complex systems must have homeostasis to maintain stability and to survive.

Homeostasis To maintain relatively stable conditions organisms must be adjusting internal conditions. The balance is maintained through feedback mechanisms.

Homeostasis Negative feedback brings about reversal of the change. Instead of the change roaming freely it's confined within a valley. When the change reaches the limits set, it encounters a steep slope and is pushed back to the set limits. (Examples: pH, glucose level, body temperature, blood pressure)

Homeostasis Positive feedback brings about greater change in same direction. Upon reaching the set limits rather than being pushed back as negative feedback would do, positive feedback forces it further outside the stable region. (Examples: childbirth, blood clotting)