IB Biology: Skin and Mucous Membranes as Barriers to Pathogens

Front

What is the primary function of the skin?

Back

The skin covers the body surface, providing a physical barrier that most pathogens find hard to penetrate.

Front

What makes the outer layer of the skin difficult for pathogens to penetrate?

Back

The thick outer layer of dead cells contains a protein called keratin, making it difficult for pathogens to penetrate and cause infection.

Front

How does the skin protect against damage?

Back

The skin protects against physical and chemical damage.

Front

What role do sebaceous glands play in skin protection?

Back

Sebaceous glands secrete sebum, which maintains skin moisture and slightly lowers skin pH, inhibiting the growth of bacteria and fungi.

Front

What are mucous membranes composed of?

Back

Mucous membranes are made up of a thin surface layer of epithelial cells over a deeper layer of connective tissue.

Front

Where are mucous membranes found in the body?

Back

Mucous membranes are found in parts of the body open to the outside, such as the nose, mouth, nasal passages, sinuses, lungs, gastrointestinal tract, head of the penis and foreskin, vagina, etc.

Front

What is the function of mucus produced by mucous membranes?

Back

The mucus contains glycoproteins and lysozyme enzymes that attack bacterial cell walls and prevent the growth of pathogens.

Front

How does mucus serve as a physical barrier?

Back

Mucus traps pathogens and harmful particles, which are either destroyed by white blood cells, swallowed, or expelled.