Homeostasis and Disease

Homeostasis

The body's ability to maintain a stable internal environment.

Antibody

A protein produced by the immune system to identify and neutralize pathogens.

Disease

A disorder of structure or function in a human, animal, or plant.

Endemic

A disease or condition regularly found among particular people or in a certain area.

Endocrine system

The system of glands that produce hormones to regulate various bodily functions.

Epidemic

A widespread occurrence of an infectious disease in a community at a particular time.

Feedback loop

A system that uses its own output as input to regulate itself.

Gland

An organ that secretes particular chemical substances for use in the body or for discharge into the surroundings.

Hormone

A signaling molecule produced by glands that regulate physiology and behavior.

Incidence

The occurrence, rate, or frequency of a disease.

Infectious

Capable of causing infection or disease.

Nervous system

The network of nerve cells and fibers that transmits nerve impulses between parts of the body.

Neuron

A specialized cell transmitting nerve impulses; a nerve cell.

Non-infectious

Not caused by infectious agents; not capable of being transmitted from one person to another.

Pandemic

An outbreak of a disease prevalent over a whole country or the world.

Pathogen

An organism that causes disease, such as bacteria, viruses, or parasites.

Receptor

A protein molecule that receives chemical signals from outside a cell.

Reflex

An involuntary and nearly instantaneous movement in response to a stimulus.

Reflex arc

The neural pathway that mediates a reflex action.

Response

A reaction to a stimulus.

Stimuli

Changes in the environment that can provoke a response.

Thermoregulation

The process that allows the body to maintain its core internal temperature.

Transmission

The act of passing a disease from one person to another.

Vaccination

The administration of a vaccine to help the immune system develop protection from a disease.

Feedback loops

Processes that help regulate body temperature, glucose, and water levels in homeostasis.

Hormones

Chemical messengers released by glands into the bloodstream to target tissues and organs.

Pituitary gland

Gland that releases Growth Hormone (HGH) for growth of bones and muscle, and ADH to regulate water balance.

Thyroid gland

Gland that releases Thyroxin, which regulates metabolism.

Pancreas

Gland that releases Insulin to regulate blood sugar levels.

Adrenal gland

Gland that releases Adrenaline, which prepares the body for 'fight or flight' responses.

Testes

Gland that produces Testosterone, responsible for male characteristics.

Ovaries

Glands that produce Oestrogen and Progesterone, involved in the menstrual cycle.

Central nervous system (CNS)

Part of the nervous system consisting of the brain and spinal cord, processing sensory information.

Peripheral nervous system (PNS)

Part of the nervous system that relays signals between the CNS and the rest of the body.

Role of the Nervous System

Coordination and control achieved by detecting and responding to changes.

Receptors

Cells that detect stimuli and convert them into electrical impulses.

Neurons

Individual nerve cells that transmit electrical impulses.

Sensory neurons

Neurons that carry electrical impulses from receptor cells towards the CNS.

Relay neurons

Neurons that carry electrical impulses from sensory neurons to motor neurons, mostly located in the CNS.

Motor neurons

Neurons that carry electrical impulses away from the CNS to effectors like muscles and glands.

Axon

Long, slender structure of a neuron that carries nerve impulses away from the cell body.

Dendrite

Branched extensions of a neuron that receive signals from other neurons.

Cell body (soma)

Main body of the neuron containing the nucleus, which supplies energy and nutrients.

Reflex action

An involuntary response to a stimulus that occurs without conscious thought.

Protective Function of Reflex Actions

Reflex actions serve a protective function; the conscious part of the brain is only aware of the action after it has occurred.

Bright Sunshine Reflex Action

Muscles around the pupil contract, making your pupil smaller, so less light enters your eye.

Touching Something Sharp Reflex Action

Biceps contract, pulling your arm away.

Sand Blowing in Eyes Reflex Action

Muscles in eyelids contract, making you blink.

Stressful Situation Reflex Action

Adrenaline is released, which increases your heart rate and blood glucose concentration.

Nerve Impulses

Travel to one part of the body along nerve fibres and usually end at a muscle.

Cerebrum

Interprets senses and regulates conscious actions such as speech, memory, behavior, and movement.

Cerebellum

Maintains balance, posture, coordination, and fine motor skills.

Brainstem

Regulates automatic body functions such as breathing and heart rate.

Fast Response

Characteristic of the nervous system, allowing for immediate reactions.

Slow Response

Characteristic of the endocrine system, allowing for gradual changes.

Voluntary Processes

Actions controlled consciously by the brain.

Involuntary Processes

Automatic actions regulated by the brain without conscious thought.

Stimulus

Any change in the environment that can provoke a response.

Receptor Cells

Cells that detect stimuli and initiate a response.

Effector

The part of the body that carries out the response to a stimulus.