Living World: Organisms, Immune System, Nervous System, Endocrine System, Circulatory System, Urinary System, Organism Interactions, Nutrient Cycles, Biotic and Abiotic Factors, Energy in an Ecosystem, Decomposers, Food Webs and Food Chains

Macro-parasites

Larger organisms that are visible to the naked eye and require a host to survive. Examples include tapeworms, roundworms, ticks, and head lice.

Infectious diseases

Diseases that can spread from person to person. Examples include the common cold, flu, and COVID-19.

First line of defense

Physical and chemical barriers that prevent pathogens from entering the body. Examples include enzymes, skin, mucus, and normal flora.

Pathogens

Disease-causing agents that spread infectious diseases to living organisms.

Bacteria

Unicellular microorganisms with cell walls but lack membrane-bound organelles. They can multiply quickly and reproduce asexually. Examples include tuberculosis, tetanus, and pneumonia.

Organelles

Subcellular structures with specific functions, such as nucleus, mitochondria, and chloroplasts.

Virus

Infectious agents consisting of genetic information surrounded by a protein coat. They cannot multiply on their own and require host cells. Examples include Covid-19 and influenza.

Prions

Protein particles capable of spreading neurological diseases. They are not alive and can be contracted through genetics or consuming infected meat. Examples include Mad cow disease and Creutzfeldt-Jakob disease.

Protozoa

Unicellular microorganisms with membrane-bound organelles, capable of motion and heterotrophy. They are commonly found in hot, moist climates and serve as a food source for larger creatures. Example: malaria.

Fungi

A large group of unicellular or multicellular organisms that feed on dead plant and animal material. They are decomposers. Examples include mold, yeast, and mushrooms.

Endoparasites

Parasites that live inside the host.

Ectoparasites

Parasites that live on the host.

Vector

An agent that does not cause the disease but helps spread pathogens.

Disease

Any condition that causes physical or mental discomfort or harm to the body. Can be infectious or non-infectious.

Non-infectious diseases

Diseases that cannot be transmitted from person to person but may be caused by genetic inheritance, nutritional factors, or environmental factors. Examples include Down syndrome, scurvy, and lung cancer.

Colony

A group of bacteria derived from the same mother cell, forming a mass.

Immune system

The body's defense system against diseases. It has three lines of defense: innate and adaptive.

Innate immune system

The non-specific immune system that is present from birth and provides the first line of defense against pathogens.

Enzymes

Biological catalysts that attack potential invaders. Examples include lysozyme in tears and mucus.

Tiny Hairs

Removal of particles by cilia in the nasopharynx.

Skin surface

The body's largest organ that protects against physical damage, pathogens, and dehydration.

Mucus lining trachea

A protective layer that traps pathogens in the respiratory tract.

Small intestine pH↑

Rapid pH change in the small intestine that inhibits the growth of pathogens.

Stomach (pH 2)

Highly acidic environment that kills many pathogens.

Normal Flora

Microorganisms that live on or in the body and help protect against pathogens.

Flushing of urinary tract

The flow of urine that helps remove pathogens from the urinary system.

Second line of defense

Consists of specialized white blood cells (phagocytes) that 'eat' foreign material to destroy them. Examples include neutrophils and macrophages.

Phagocytes

White blood cells that engulf and digest pathogens through phagocytosis.

Monocytes

A type of white blood cell involved in immune responses.

Lymphocytes

White blood cells involved in the adaptive immune response. Divided into B cells and T cells.

Eosinophil

A type of white blood cell involved in immune responses, particularly against parasites.

Basophil

A type of white blood cell involved in immune responses, particularly against allergies.

Neutrophil

A type of white blood cell involved in phagocytosis during acute infections.

Macrophages

A type of white blood cell involved in phagocytosis during chronic infections.

Acquired immune system

The immune system that is acquired through exposure to specific pathogens. It consists of B cells and T cells.

B cells

Lymphocytes that produce antibodies to attack foreign pathogens outside body cells.

Antibodies

Y-shaped protein molecules that bind to antigens on pathogens, marking them for destruction by other cells of the immune system.

T cells

Lymphocytes that attack infected body cells. Divided into cytotoxic T cells and helper T cells.

Cytotoxic T cells

T cells that signal infected body cells to self-destruct.

Helper T cells

T cells that secrete chemicals to draw other immune cells to the site of infection.

Memory cells

B and T cells that remain in the body after an infection, ready to recognize and respond quickly to the same antigen in case of reinfection.

Vaccines

Substances that stimulate the production of antibodies and memory cells by exposing the body to weakened or inactive parts of a pathogen.

Nervous system

The body's communication network, consisting of the central nervous system (CNS) and peripheral nervous system (PNS).

Central nervous system (CNS)

Made up of the brain and spinal cord, acting as a control center.

Peripheral nervous system (PNS)

Consists of ganglia and nerves around the body, connecting the CNS to the rest of the body.

Spinal nerves

31 pairs of nerves that connect the spinal cord to the rest of the body.

Automatic nervous system

Controls glands and organs without conscious thought.

Somatic nervous system

Carries conscious commands from the CNS to muscles and glands.

Neurons

Nerve cells that send electrochemical signals to and from the brain and other parts of the nervous system.

Axon

An electricity conduction fiber of a neuron that sends signals away from the cell body.

Myelin sheath

A coating that insulates the axon, increasing the speed of signal transmission.

Dendrites

Extensions of a neuron cell body that receive messages from other neurons.

Synapses

Junctions/gaps between two neurons where neurotransmitters are released.

Neural impulses

Electrical signals that travel through a neuron, from dendrites to axon terminals.

Sensory Neurons

Neurons that send information gathered from receptors to the CNS.

Motor Neurons

Neurons that carry signals/responses from the CNS to effectors (muscles and glands).

Interneurons

Smaller neurons responsible for linking sensory and motor neurons, found in the CNS.

Receptors

Specialized cells that detect different types of stimuli in sensory organs.

Effectors

Muscles and glands that carry out responses created by the CNS to adapt to stimuli.

Stimulus

A change in the internal or external environment that evokes a response.

Homeostasis

A self-regulating process that maintains a constant, stable internal condition in response to internal or external changes.

Feedback loop

A sequence of steps that continually adjusts the body to maintain homeostasis.

Negative feedback loop

A feedback loop that returns a variable to a set condition. Helps maintain homeostasis.

Reflex arc

A simple nervous system process that bypasses the brain to produce rapid, involuntary actions.

Endocrine system

Regulates mood, growth, development, metabolism, and other processes through the release of hormones.

Hormones

Chemicals released by glands into the bloodstream to trigger responses in target cells.

Thyroid gland

Located in the neck, it secretes thyroxine and triiodothyronine, which affect metabolism and growth.

Parathyroids

Small glands alongside the thyroid gland that secrete parathyroid hormone, which helps regulate calcium, phosphate, and vitamin D.

Testis

Located in the scrotum, it secretes testosterone, the male sex hormone.

Ovary

Located on either side of the uterus, it secretes estrogen, the female sex hormone.

Pancreas

Located inside the abdomen, it secretes insulin and glucagon to regulate blood sugar levels and aid in digestion.

Adrenal glands

Located above the kidneys, they secrete adrenaline to trigger the fight-or-flight response and help cope with stress.

Hypothalamus

A region of the brain attached to the pituitary gland. It monitors the body's internal well-being and controls various functions.

Pituitary gland

Located at the base of the brain, it secretes many different hormones and controls several other endocrine glands.

Pineal gland

Located at the base of the brain, it secretes melatonin to regulate the sleep-wake cycle.

Auxins

Plant hormones that regulate growth and development, particularly in response to light and gravity.

Gibberellins

Plant hormones that promote stem elongation and seed germination.

Cytokinins

Plant hormones that promote cell division and delay aging.

Ethylene

A plant hormone that promotes fruit ripening and senescence (aging).

Abscisic acid

A plant hormone that inhibits growth and promotes seed dormancy and stress responses.

Phototropism

A plant's growth response to light intensity, causing it to grow towards the light.

Geotropism

A plant's growth response to gravity, causing shoots to grow up and roots to grow down.

Hydrotropism

A plant's growth response to the presence of water, causing it to grow towards water.

Thigmotropism

A plant's growth response to touch or contact with a solid surface.

Circulatory system

Transports oxygen, nutrients, and waste products throughout the body. Consists of the heart, blood vessels, and blood.

Red blood cells

Carry oxygen in the blood.

White blood cells

Part of the immune system, fight pathogens.

Platelets

Needed for blood clotting.

Blood plasma

The liquid component of blood that carries other substances.

Arteries

Blood vessels that carry blood away from the heart.

Capillaries

The smallest blood vessels that allow for the exchange of gases and nutrients with body cells.

Veins

Blood vessels that carry blood towards the heart.

Urinary system

Filters waste products from the blood and produces urine. Consists of the kidneys, ureters, bladder, and urethra.

Kidneys

Filter waste products from the blood and regulate salt and water levels.

Ureters

Transport urine from the kidneys to the bladder.

Bladder

Stores urine.

Urethra

Transports urine from the bladder to the outside of the body.

Ecology

The study of interactions between organisms and their environment.

Population

A group of organisms of the same species living in the same area at the same time.

Community

A group of populations living and interacting with each other in a common area.