3.2.1 Powers of Protection

What are the six major types of infectious agents?

1. Prions

2. Viruses

3. Bacteria

4. Protists

5. Fungi

6. Helminths

Pathogen

Any infectious agent that can cause a disease. Pathogens can be non-living or living and can be visible to the naked eye or only visible with a microscope

Prions (what they are, how they infect, treatment, prevention, & example)

• Non-living, submicroscopic proteins

• Causes normal proteins in the brain to fold abnormally

Viruses (what they are, how they infect, treatment, prevention, & example)

• Non-living microscopic agents made up of an outer protein shell (capsid) and either DNA or RNA

• May occur through touch, saliva, blood, or sexual contact

• They cannot replicate on their own; they need a host

• The host’s cells and tissues are destroyed

Bacteria (what they are, how they infect, treatment, prevention, & example)

• Living, microscopic, unicellular, prokaryotic organisms

• Can occur through the nose, eyes, mouth, through a wound, or by ingesting contaminated food or water

• Bacteria can invade cells, cause tissue damage, and produce harmful toxins

Protists (what they are, how they infect, treatment, prevention, & example)

• Living, microscopic, single-celled, eukaryotic, animal-like organisms

• Infection typically results from ingestion of food or water contaminated with feces from an infected organism

• Infects the digestive tract, blood, or organs of the body, depriving the host of essential nutrients found in food (may also cause tissue & organ damage)

Helminths (what they are, how they infect, treatment, prevention, & example)

• Living, multicellular, eukaryotic worms. Both microscopic and macroscopic varieties exist

• Infection may occur from the consumption of contaminated food or water, or getting bitten by an infected insect

• Depriving the host of essential nutrients found in food can cause tissue & organ damage

Fungi (what they are, how they infect, treatment, prevention, & example)

• Living, multicellular, eukaryotic organisms (yeasts, mildew, molds, and mushrooms). Both microscopic and macroscopic varieties exist

• Some forms infect when the spores of the fungi, the reproductive cells, are inhaled or land on a host

• Infection can result in tissue damage

Parasites

Living things that use other living things for food and a place to live

How does the skin protect the body?

It is the first layer of defense for the body and is an immediate barrier to outside invaders

How does the immune system protect the body?

It acts as an army to fight and destroy pathogens

How does the lymphatic system protect the body?

It drains and filter excess fluid while the immune system is fighting and destroying pathogens

How does mucus protect the body?

It covers cells that line our respiratory and digestive systems and helps trap pathogens that enter the body

How is mucus expelled?

It is either swallowed to be destroyed by the stomach or released when you blow your nose

What are the 3 layers of the skin from surface to deepest?

1. Epidermis

2. Dermis

3. Subcutaneous fatty tissue

What does the skin act as a protective barrier between?

Internal structures and the outside world

Epidermis

The top layer of the skin that provides a barrier, makes new skin, and provides skin color

Dermis

The middle layer of skin that contains collagen and elastin, grows hair, makes oil and sweat, and contains blood vessels and nerve endings

Subcutaneous Fatty Tissue

The bottom layer of the skin, consisting of fat that cushions muscles and bones and helps to regulate body temperature

What is the unique environment that the skin represents?

Immune cells interact with skin cells to maintain tissue homeostasis and induce immune responses

What does normal flora have beneficial effects for?

The protection against pathogens and in wound healing

What is the epidermis composed of?

Highly specialized epithelial cells known as kertinocytes

How are keratinocytes continuously replenished?

From just one layer of basal keratinocytes, which divide frequently

Dead cells (corneocytes)

Largely responsible for the barrier function of the skin

How is the dense extracellular matrix formed?

In the dermis, cells known as fibroblasts secrete elastin and collagen fibers

What do blood capillaries do in the skin?

They irrigate the dermis

Where is lymph fluid drained?

Through lymphatic vessels to lymph nodes

Sepsis

The body’s immune system overreacts to an infection, causing inflammation

Severe Sepsis

Organs in the body begin to malfunction, blood pressure is low, and inflammation continues

Septic Shock

Extremely low blood pressure that does not respond to IV fluids

TIME

T~ Temperature (higher or lower than normal)

I~ Infection (signs and symptoms, such as swollen lymph nodes)

M~ Mental decline (confused, sleepy, difficult to rouse)

E~ Extremely ill (severe pain or discomfort)

What is the lymphatic system made up of?

Organs, ducts, and lymph nodes

What fluid does the lymphatic system transport?

A clear watery fluid called lymph

Lymph Node

Any of the rounded masses of lymphoid tissue that are surrounded by a capsule of connective tissue, are distributed along the lymphatic vessels, and contain numerous lymphocytes, which filter the flow of lymph passing through the node

Lymph

A usually clear fluid that passes from the intercellular spaces of body tissue into the lymphatic vessels

What does the lymphatic system absorb, protect your body from, and do with lymph fluid?

It absorbs fat from the digestive tract, protects your body from pathogens, and transports and removes waste from the lymph fluid

List one thing from the lymphatic system, digestive system, and skeletal system that protect your body from outside invaders

1. Lymph nodes (lymphatic system)

2. Liver (digestive system)

3. Bone marrow (skeletal system)

What does the immune system do to anything that is non-self?

It works to fight off and destroy anything that is non-self

What do white blood cells do?

Circulate through the blood and lymph to fight off invaders such as viruses, bacteria, or abnormal cells, such as cancer cells, and protect the body while it’s under attack

Tonsils

Help to stop germs from entering the body through the mouth or the nose. They contain white blood cells which help kill germs. You can live a healthy life without tonsils

Lymph Nodes

Glands in the immune system that usually enlarge in response to a bacterial or viral infection, or cancer

Thymus

Helps in the development of T-cells. T-cells are a type of white blood cell that help fight infections. It is especially important in newborns; without a thymus, a baby’s immune system will not develop properly. Adults can live without a thymus

Bone Marrow

Produces new blood cells, both red and white. The types of cells that make antibodies, B cells, are formed here. All mammals need bone marrow to live healthy lives

Liver

The liver contributes to your immune defense by collecting and eliminating foreign compounds from the large volume of blood that passes through it. You cannot survive without a liver

Spleen

Filters the blood of foreign cells and old red blood cells in need of replacement. A person missing their spleen gets sick much more often than someone with a spleen

How does the lymphatic system transport substances?

• Lymph fluid is not pressurized

• Lymph fluids are pushed through the body by normal body motions

• The lymphatic vessels have a series of valves that help keep the fluid moving in one direction

How does the cardiovascular system transport substances?

• Blood is pressurized

• Blood moves due to the pumping of the heart

How many lymph nodes does the average adult have, and where are they typically clustered?

600-800, typically clustered in the groin, armpit, and neck areas

How are nodes connected, and what do they do?

They are connected by lymphatic vessels that carry excess lymph away from the tissues toward larger collecting ducts

What happens where the vessels reach the nodes?

The lymph moves through the sinuses and white blood cells attack any pathogens. It then flows out of the node through the efferent vessel to be returned to the bloodstream

What do swollen lymph nodes indicate?

That you have an infection

Where does bacteria reside when it enters your body?

Between cells in the intercellular fluid

What does the lymph system do concerning intercellular fluid?

Drains and filters intercellular fluid and detects and removes bacteria

What do small lymph vessels collect?

Intercellular fluid & moves it toward larger vessels

Where does the lymph fluid move after the larger vessels?

Into the lymph nodes for processing

What kind of cells do lymph nodes contain?

Filtering tissue and lymph cells

What happens to lymph nodes when fighting infections?

The nodes swell with bacteria and the cells fighting the bacteria

What happens after lymph is filtered through the lymph nodes?

It re-enters the bloodstream

Label the diagram

1. Cilia

2. Mucus

3. Columnar Epithelium

4. Goblet Cells

5. Basal Cells

Label the diagram

1. Epidermis

2. Oil gland (sebaceous gland)

3. Dermis

4. Hair

5. Subcutaneous fatty tissue (hypodermis)

6. Muscle fibers

Label the diagram

1. Tonsils

2. Lymph nodes

3. Thymus

4. Bone marrow

5. Lymph vessels

6. Liver

7. Spleen

Label the diagram

1. Capsule

2. Afferent vessel

3. Arteries

4. Veins

5. Medulla

6. Efferent vessel

7. Valve

8. Sinus

9. Germinal center

10. Cortex

Why are cilia important for your trachea and bronchiole tubes?

The cilia pushes any material breathed in from the air to the back of your throat

When do bacteria officially enter your body?

When it enters your bloodstream

What is the job of epithelial tissue?

Protect

Is epithelial tissue avascular or vascular?

Avascular

What is the job of connective tissue?

Connect

Is connective tissue avascular or vascular?

Vascular

Give examples of connective tissue

• Subcutaneous fatty tissue

• Dermis

• Lymph

• Blood

What is another name for subcutaneous tissue?

Hypodermis