UNIT 3 Human Biology ATAR

Homeostasis

Maintenance of a stable internal environment within tolerance limits.

Tolerance Limits

Upper and lower limits the body can function within.

Negative Feedback

Reverses a change to return conditions to normal.

Positive Feedback

Amplifies a change.

Intracellular Fluid

Fluid within the cells.

Extracellular Fluid

Fluid outside the cells including blood plasma, tissue fluid, and lymph.

Osmotic Pressure

Movement of water due to solute concentration.

Excretion

Removal of metabolic wastes.

Hyperglycaemia

Condition of having high blood glucose.

Hypoglycaemia

Condition of having low blood glucose.

ADH (Antidiuretic Hormone)

Hormone that increases water reabsorption in the collecting duct.

Aldosterone

Hormone that increases sodium reabsorption, leading to water following sodium.

Insulin

Hormone that increases glucose uptake and glycogenesis.

Glucagon

Hormone that stimulates glycogenolysis.

Antigen

A foreign molecule that triggers an immune response.

Antibody

Protein made by B cells to neutralize antigens.

Humoral Immunity

B cells produce antibodies targeting extracellular pathogens.

Cell-Mediated Immunity

T cells destroy infected cells targeting intracellular pathogens.

Dendrites

Structures in neurons that receive signals.

Axon

Part of a neuron that transmits impulses.

Neurotransmitters

Chemical messengers that cross synapses.

Pyrogens

Substances that induce fever.