Animal Systems: DEFENSE Integumentary, Immune and Lymphatic Systems

DEFENSE How do the integumentary, immune and lymphatic systems work together to defend the body? These systems work to protect the body from pathogens. The integumentary system (skin) is the first barrier against infection, and any invading pathogens are destroyed and removed via the immune and lymphatic systems.

Integumentary System Integument – Latin “to cover”

Functions of the Integumentary System Purpose: Protection : Protects deeper tissues (organs) Blocks UV radiation Prevents infectious agents from entering the body Aids in temperature regulation (sweat or shiver)

Functions of the Integumentary System cont. Prevents dehydration Produces Vitamin D – from sunlight Vitamin D increases absorption of calcium for healthy bones Aids in excretion of wastes (salts) Sensory organ (heat, cold, pressure and pain receptors)

Parts of the System: Skin is composed of three layers: Epidermis – outer layer, site of rapid cell division (mitosis), production of keratin and melanin. Melanocytes – give skin pigmentation and protect from UV rays http://youtu.be/ClynhFKMs3c

Parts of the System: Skin is composed of three layers: Dermis – inner layer, contains major structures of skin Collagen, blood vessels, nerve endings, glands, sensory receptors, hair follicles Subcutaneous fat – adipose tissue, provides insulation for body

Evolutionary Trends of Integumentary System Simple Complex Animal Taxon Simple Invertebrates Vertebrates Adaptations Simple integumentary system used predominantly for diffusion. Diffusion allows movement of gases, nutrients, fluids, and wastes products in and out of the organism to maintain homeostasis. More complex integumentary system. Used to maintain internal body temperature, fluid and salt levels. Contains nerve receptors, glands, subcutaneous fat, hair follicles to interpret environmental stimuli. Picture of Adaptation   Some organisms contain structures such as feathers, scales, and mucous glands for additional protection and support Examples Jellyfish, Flat worms, Earthworms, Sponges Mammals, Reptiles, Amphibians, Fish, Birds

Integumentary System Levels of Organization Epidermis, Dermis Skin Integumentary Epithelial Cells (skin cells)

Fun Fact: Believe it or not, the integumentary system is the largest organ system and your skin is the largest organ in your body.

Interaction with Other Body Systems Skin is the first line of defense in the immune system response. The circulatory system and skin regulate body temperature. Skin and the excretory system excrete water, urea, salts, and other wastes through sweat. Receptors of the nervous system are located in skin.

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Dear 16-Year-Old Me http://www.youtube.com/watch?v=_4jgUcxMezM

https://www.youtube.com/watch?v=o9BqrSAHbTc

Lymphatic System Purpose: Collects fluid lost by the blood during movement of nutrients into body tissues and returns it back to the circulatory system. Plays a role in the immune system by producing, storing and circulating white blood cells. Network of vessels and associated organs: 1. lymph – fluid in lymph vessels 2. lymph vessels – move the lymph throughout the body 3. lymph nodes - densely packed areas of tissue that filter the lymph; white blood cells are stored in them

4. Tonsils, thymus and spleen are all composed of lymphoid tissue tonsils – filter and destroy bacteria thymus – produces hormones that aid in maturation of T-cells; T-cells recognize foreign pathogens spleen – removes worn-out red blood cells from circulatory system; contains white blood cells that engulf and destroy bacteria.

To review: The lymphatic system removes fluid from around cells and returns it to the blood. When this fluid passes through the lymph nodes white blood cells attack and kill any pathogens.

Interactions with other Body Systems Lymphatic system works with the circulatory system to maintain homeostasis of body fluids. Lymphatic system plays a role in the immune system by producing white blood cells and destroying pathogens within lymph nodes and spleen. The excretory system excretes excess fluids.

Immune System Purpose: The immune system protects the body from disease by producing specialized cells that inactivate or destroy pathogens.

Parts of the System - consists of specialized cells and organs Parts of the System - consists of specialized cells and organs that respond to the presence of a pathogen skin – body’s first line of defense (also part of integumentary system) white blood cells – recognize disease agents (antigens) and create antibodies to tag and remove these antigens. Macrophages are the white blood cell type that actually eat and destroy these antigens. Macrophage of a mouse stretching its “arms” (pseudopodia) to engulf 2 pathogens

How the Immune System works: 1. First line of defense (pathogen does not enter body) Skin & other non-specific defenses such as mucous, saliva, and tears trap and destroy pathogens.

2. Second line of defense (pathogen enters body) If pathogen does enter the body, this triggers the inflammatory response – Tissue becomes swollen and painful due to white blood cell accumulation.

Chemicals are released by immune system to cause fever (increased body temperature); increased temperature can kill some bacteria and viruses. White blood cells called macrophages engulf and destroy pathogens.

3. Third line of defense (pathogen gets past first and second 3. Third line of defense (pathogen gets past first and second line of defense) Immune response 1. Triggered by an antigen; virus, bacteria or other pathogen. 2. T cells and B cells recognize the specific pathogen and produce antibodies that will help destroy the invader and protect us the next time it enters the body. This process is called immunity. 3. The reaction to a second infection by the same pathogen is much faster. Antigen Antibody Antigen binding sites

Lymph & Immune System Levels of Organization Lymph nodes, bone marrow Spleen, Liver Lymph and Immune White Blood Cells, B-cells, T-cells, macrophages

**H.I.V. is the virus that causes AIDS, or acquired immune deficiency syndrome. It attacks a special T cell known as a helper T cell. **Penicillin and other antibiotics can also be used to help the immune system, but it is important to remember that antibiotics only kill bacteria! **Vaccines work by mimicking the body’s natural immune response. A small amount of the specially treated virus, bacterium or toxin (vaccine) is injected into the body. The body then makes antibodies. If a vaccinated person is exposed to the actual virus, bacterium or toxin, they won’t get sick.

Interactions with other Body Systems Skin of the integumentary system is the first line of defense of the immune system. The circulatory system transports immune cells around the body. Bones of the skeletal system produce lymphocytes and macrophages.