Unit 3: 17.1

Question 1

What are the types of physical defenses?

Answer 1

1. Physical barriers
2. Mechanical defenses
3. Microbiome

Question 2

What are Mechanical defenses

Answer 2

They physically remove microbes and debris from areas of the body where they might cause harm or infection

Question 3

Microbiota

Answer 3

Physical defenses that competes with pathogens for nutrients and cellular binding sites that cause infection

Question 4

What do Physical defenses do?

Answer 4

Provide the body’s most basic form of nonspecific defense

Question 5

What are Physical barriers

Answer 5

Prevent microbes from reaching tissues

• skin barrier
• mucous membranes
• endothelia

Question 6

Skin barrier

Answer 6

Most important physical barrier

• has 3 layers of closely packed cells
  1. Epidermis (upper layer)
  2. Dermis (has follicles sweat glands nerves and blood vessels)
  3. Hypodermis (layer of fatty tissue that has blood and lymph vessels)

Question 7

Keratin

Answer 7

Top layer of skin has cells packed with keratin.

-make the skin rough and resistant to bacterial enzymes

Question 8

Fatty acids on top skin layer

Answer 8

Create dry, salty, and acidic environment that inhibits growth of microbes

Question 9

Skin shedding

Answer 9

Skin can shed dead cells and any microbes that were in them

Question 10

Mucous membranes

Answer 10

Found in lining of the nose, mouth, lungs, and urinary and digestive tracts
-made of a layer of epithelial cells that secrete mucus that has anti microbial peptides
-mucus traps debris and microbes
PHYSICAL DEFENSE

Question 11

Ciliated epithelial cells

Answer 11

Mechanical defense found in respiratory tract (mucoculiary blanket)
-cells have cilia that propels debris away from lungs

Question 12

Mucoculiary escalator

Answer 12

Ciliated epithelial cells propel debris/microbes away from lungs, the expelled music is then swallowed/destroyed in stomach, coughed up, or sneezed out
MECHANICAL DEFENSE

Question 13

Peristalsis

Answer 13

Mechanical defense where muscular contractions in digestive tract moves mucus and other material though the intestines, rectum, and anus, microbes come out as poop

Question 14

Endothelia

Answer 14

Tightly packed cells make a barrier against microbes

• physical defense
• found in lining of: urogenital tract, blood vessels, lymph vessels

Question 15

Flushing of Uribe and tears are examples of?

Answer 15

Mechanical defenses

Question 16

Microbiome

Answer 16

Important first line defense against invading pathogens

• occupies cellular binding sites
• competes for nutrients
• resident microbiota prevents pathogens from attaching

Question 17

Cellular barriers

Answer 17

Physical defense

• Skin, mucous membranes, endothelial cells
• deny entry to pathogens

Question 18

Mechanical defenses summary

Answer 18

• shedding of skin cells, mucociliary sweeping, peristalsis, flushing urine/tears
• remove pathogens from potential site of infection