Organs and Organ Systems

Textbook: Chapter 10

Organ

Composed of 2 or more different tissues that work together to peform a specific function

Organ System

Composed of organs with a common function

Integumentary System (skin)

• Protects underlying tissues

• Provides skin sensation

• Helps regulate body temp.

• Synthesizes vitamin D

Skeletal System

• Attachment for muscles

• Protects organs

• Stores calcium and phosphorus

• Produces blood cells

Muscular System

• Moves body and maintains posture

• Internal transport of fluids

• Generation of heat

Nervous System

Regulates and integrates body functions via neurons

Endocrine System

Regulates and integrates body functions via hormones

Cardiovascular System

• Transports nutrients, respiratory gases, wastes, and heat

• Transports immune cells and antibodies

• Transports hormones

• Regulates pH

Lymphatic System

• Returns tissue fluids to bloodstream

• Protects against infection and disease

Respiratory System

Exchanges respiratory gases with the environment

Digestive System

• Physical and chemical breakdown of food

• Absorbs, processes, stores food

Urinary System

Maintains constant internal environment through the excretion of nitrogenous waste

Reproductive System

• Produces and secretes hormones

• Produces and releases egg and sperms cells

• Houses embryo/fetus (females only)

• Produces milk to nourish offspring (females only)

Internal Body Cavities

Protect vital organs and allow them to slide past one another and change shape (2 types)

Ventral Cavity

Thoracic Cavity;

• Pleural cavities (lungs)

• Pericardial cavity (heart)

• Abdominal cavity (digestive system, urinary system, and reproductive system)

Dorsal Cavity

• Cranial cavity (brain)

• Spinal cavity (spinal cord)

Membranes

Cover body cavities and organ surfaces (sheets of epithelium supported by connective tissues)

Mucous Membranes

Line passageways that open to the exterior of the body

Serous Membranes

Line the thoracic and abdominal cavities and the organs within them

Synovial Membranes

Line the cavities of freely moveable joints

Cutaneous Membrane (skin)

Covers the outside of the body

The Skin

• Our largest organ

• Functions:

  • Protects against bacterial invasion, UV radiation, and physical and chemical stress

  • Prevents water loss

  • Regulates body temp.

  • Synthesizes vitamin D

  • Receives stimuli

Skin Color

• Determined by:

  • Blood flow

  • Distribution and quality of the pigment melanin (produced by melanocytes at base of epidermis, comes in yellow-to-red or black-to-brown)

Skin Cancer (overexposure to the sun)

• Basal Cell Carcinoma: most common, arises in the rapidly dividing cells of the deepest layer of the epidermis

• Squamous Cell Carcinoma: 2nd most common, arises in the newly formed skin cells as they flatten and move towards the skin surface

• Melanoma: least common and most dangerous type of skin cancer

Homeostasis

Constant adjustment made by the organ systems to respond to changes in the internal and external environments (depends on the nervous and endocrine systems (internal communication))

Negative Feedback Mechanisms

Corrective measures that slow or reverse variation from a normal value (once the normal value is reached, corrective measures cease)

• Ex: blood sugar regulation

Positive Feedback Mechanism

Cause a change that promotes continued change in the same direction

Homeostatic Mechanisms (3 Components)

• Receptor: detects a change in the internal or external environment

• Control center (brain): integrates the information coming from all receptors and selects appropriate response

• Effector (muscle or gland): carries out the response

Thermoregulation (Hypothalamus and Body Temp.)

• Receptors: thermoreceptors

• Control center: hypothalamus

• Effectors: sweat glands, blood vessels in the skin, and skeletal muscles

  • Ex:

    • Hyperthermia: abnormally elevated body temp.

    • Hypothermia: abnormally low body temp.