Natural Disease Defenses Flashcards
What physical defences do plants have?
- Bark (lignin)
- Waxy cuticle
- Thorns, spines and hairs
- Shrivelling/folding leaves
- Cellulose cell walls
- Mimicry
What chemical defences do plants have?
- Releasing chemicals/hormones signalling other plants to defend themselves
- Histamine
- Toxic chemicals
- releasing hormones that attract predators to pests
- Antibacterial molecules
What are human first lines of defence?
Skin
Scabs
Nose hair and mucus
Cilia cells
Eyelashes/tears
Stomach acid
What does a non specific defence system mean?
It aims to block/destroy ALL microorganisms
How does skin prevent disease?
- Barrier between inside and outside
- Shedding skin
- Sebaceous glands produce anti microbial oils
How do scabs prevent disease?
- platelets make fibrin, pulling edges together
- mesh forms trapping RBCs, forming a clot
- dries into a scab
- stops pathogens entering body
How do nose hairs and mucus prevent disease?
- nose hair traps larger particles
- mucus traps pathogens
How do cilia cells prevent disease?
- hair-like projections waft mucus away
- found in lungs
- goblet cells between them for mucus production
How do tears prevent disease?
- high salt concentration dries up pathogens
- lyzosomes break down pathogens
- washes out pathogens
How do eyelashes prevent disease?
They trap dirt and pathogens
How does stomach acid prevent disease?
- low pH (2) HCl destroys pathogen cell walls, killing them
- stomach lining prevents damage to body
What are the 2 main types of WBCs?
Phagocytes and lymphocytes
Describe the process of phagocytosis
- phagocytes leave blood through capillary walls and enter tissue that is being attacked
- cell membrane and cytoplasm of phagocyte surround the pathogen
- pathogen is engulfed by phagocytosis
- pathogen is digested by lytic enzymes, useful substances are absorbed and waste is released by exocytosis
- phagocyte continues to engulf more pathogens
Define antigens
A substance capable of stimulating an immune response.
Often on the surface of a pathogen but can also be a toxin or chemical
Define antibodies
A protective protein produced by immune system in response to presence of antigens
Antibodies recognise and latch onto antigens in order to remove them from body
How do lymphocytes destroy pathogens?
- they have antibodies on their surface which vond to specific antigens on surface of pathogens
- when the antigen is detected, vast amounts of copies of antibodies are produced
- antibodies lock onto matching antigens allowing pathogens to be destroyed
What adaptations do phagocytes have for their purpose?
Lots of mitochondria for energy for phagocytosis
Lots of ribosomes for lytic enzymes
What adaptations do lymphocytes have for their purpose?
Lots of ribosomes for antibody production
