Immune System Overview

Immune System

• Viruses are microscopic infectious agents made of genetic material and proteins. Chickenpox is a viral example.
• Bacteria are single-celled microbes without nuclei. E. coli is an example.
• Antibodies are proteins that identify and fight specific pathogens.
• Pathogens are microorganisms causing disease (e.g., E. coli, measles virus).
• Viruses are composed of genetic material within a protein or fat layer.
• The immune system has lines of defense:
  • Non-specific defenses (innate immunity) —The first line (skin, mucous membranes, secretions) and second line (antimicrobial proteins, inflammatory response, fever) act as general barriers and responses.
  • Specific defenses (adaptive immunity) —The third line, using lymphocytes and antibodies, provides targeted responses against specific pathogens. Memory cells are created to fight repeat infections.
• Vaccines create memory cells to recognize and fight specific pathogens.
• Signs of infections include inflammation, fever, and redness.
• The immune system is the body's defense against invading pathogens

Physical and Chemical Barriers

• Skin, mucous membranes, and cilia act as physical barriers that prevent pathogens from entering the body.
• Stomach acid, tears, saliva, urine, lysozyme, sebum, and acidic skin pH are chemical barriers, creating an inhospitable environment for many pathogens

Vaccination vs. No Vaccination

• Vaccinated people have memory cells with antibodies ready to fight pathogens, preventing severe illness.
• Non-vaccinated people don't have these antibodies, making them more susceptible to severe symptoms as their body builds antibodies from scratch

Nervous System

• Dendrites are part of a neuron.
• Nervous systems process information received from the body then transmit it.

Endocrine System

• Hormones, like adrenaline, regulate homeostasis.
• Homeostasis is regulated through positive and negative feedback systems.
• Mammals regulate their body temperature through homeostasis, which differs from reptiles.
• Insulin and glucagon regulate blood glucose levels.

Ecosystem

• Predators and prey compete for resources (food, shelter, mates).
• Predator-prey interactions can affect the numbers of each species.
• Energy transfer decreases from producers to consumers.
• Energy is lost through respiration, waste products, and heat in different ecosystems.

Symbiosis

• Symbiosis is a relationship where at least one organism benefits.
• Mutualism (+/+): both organisms benefit (e.g., oxpeckers and buffalo).
• Commensalism (+/0): one organism benefits, the other is unaffected (e.g., shrimp and nudibranch).
• Parasitism (+/-): one organism benefits, the other is harmed (e.g., ticks and buffalo).

Predator/Prey Graphs

• Removing a predator can increase the population of its prey.
• Removing a prey can decrease the population of its predators.