Comprehensive Biology Review: Diseases, Immunity, Endocrine, and Nervous Systems

Vocabulary-style flashcards covering the study of infectious/non-infectious diseases, the body's immune defenses (including innate and specific immunity), the endocrine system's hormonal regulation, and the structural/functional divisions of the nervous system.

Disease

An abnormal condition that disrupts normal body structure or function and is not caused by immediate injury.

Infectious diseases

Diseases caused by pathogens that can be transmitted between organisms.

Non-infectious diseases

Diseases not caused by pathogens that cannot be transmitted.

Viruses

Non-living pathogens that replicate inside host cells.

Bacteria

Unicellular organisms that produce toxins to cause disease.

Fungi

Pathogens that cause disease by absorbing nutrients from host cells.

Protozoa

Unicellular parasites.

Multicellular parasites

Organisms such as worms that cause disease.

Vectors

Organisms like mosquitoes used as a mode of pathogen transmission.

Epidemic

The rapid spread of an infectious disease in one region.

Pandemic

The global spread of an infectious disease.

Endemic

An infectious disease that is constantly present.

Vaccination

Introduces weakened antigens to stimulate immune memory and build immunity without causing disease.

Cancer

A non-infectious disease characterized by uncontrolled cell division.

Allergies

An immune response to harmless substances involving the release of histamine.

Autoimmune diseases

Conditions where the immune system attacks the body's own cells.

First line of defense

Nonspecific physical and chemical barriers such as skin and mucus.

Second line of defense

Innate immunity involving nonspecific responses like phagocytes and inflammation; present at birth.

Third line of defense

Adaptive immunity involving specific responses and the need for memory cells.

Phagocytosis

The process where phagocytes engulf and destroy pathogens.

Mast cells

Cells that recognize foreign material and secrete histamine to increase blood flow.

Antigens

Protein markers found on the surface of cells and pathogens.

Antibodies

Proteins produced by immune cells that bind specifically to antigens.

Lymphatic system

A network of organs and vessels (including nodes, spleen, thymus, and bone marrow) that produces, stores, and activates T and B lymphocytes.

Helper T cells

T cells that activate and coordinate the immune response.

Cytotoxic T cells

T cells that directly kill infected cells.

Memory T cells

T cells that remain after infection to enable a faster and stronger response if the same pathogen re-infects.

Plasma cells

B cells that release antibodies to recognize and neutralize pathogens.

Active Immunity

Immunity where the body produces its own antibodies, such as through infection or a vaccine.

Passive Immunity

Immunity where antibodies are received externally, such as through breastfeeding or a blood transfusion.

Hormones

Chemical messengers released into the bloodstream that act only on target cells with complementary receptors.

Steroid hormones

Lipid-based hormones that pass through cell membranes and affect gene expression (e.g., testosterone, estrogen, cortisol).

Non-steroid hormones

Amino-acid-based hormones that bind to surface receptors on the cell membrane to activate enzymes.

Pituitary gland

Known as the master gland; located at the base of the brain and releases hormones like TSH and growth hormone to control other glands.

Thyroxine

A hormone produced by the thyroid gland that regulates the body's metabolic rate.

Hypothyroidism

A condition where an underactive thyroid leads to low thyroxine levels, decreased metabolism, weight gain, and sleepiness.

Hyperthyroidism

A condition where an overactive thyroid leads to high thyroxine levels and increased metabolism, causing unexplained weight loss.

Insulin

A pancreatic hormone that lowers blood glucose levels after a meal.

Glucagon

A pancreatic hormone that raises blood glucose during fasting by releasing stored glucose from the liver.

Type 1 Diabetes

An autoimmune condition where the pancreas fails to produce insulin.

Type 2 Diabetes

A condition linked to poor lifestyle habits where cells fail to respond to insulin.

Adrenaline

A hormone produced by the adrenal glands that prepares the body for stress (fight-or-flight) by increasing heart and breathing rates.

Sensory neurons

Neurons that detect stimuli from receptors and transmit impulses to the Central Nervous System (CNS).

Interneurons (relay neurons)

Neurons that process and interpret information within the CNS and connect sensory to motor neurons.

Motor neurons

Neurons that carry impulses from the CNS to effectors (muscles or glands).

Reflex Arc

A fast, automatic stimulus-response pathway that bypasses the brain initially by going through the spinal cord only.

Myelin sheath

A covering on axons that makes the transmission of nerve impulses much faster.

Synapse

A small gap between neurons where chemical signaling occurs via neurotransmitters.

Cerebrum

Part of the brain responsible for thinking, memory, learning, voluntary movements, and processing sensory information.

Cerebellum

Part of the brain responsible for balance, posture, and coordination or movements.

Brainstem

Part of the brain that controls breathing, heart rate, and blood pressure.

Hypothalamus

Brain structure that maintains homeostasis (regulating temperature, hunger, thirst) and links the nervous and endocrine systems.

Autonomic Nervous System

Part of the Peripheral Nervous System that controls internal organs and glands involuntarily; divided into parasympathetic and sympathetic.