Glossary

• Homeostasis = regulation of internal conditions to maintain a stable environment within a narrow range
• Tissue fluid = fluid surrounding cells that facilitates exchange of nutrients and gases between blood and cells
• Water potential = tendency of water molecules to move from one area to another
• Optimum point = ideal value of a physiological variable at which cellular processes function most efficiently
• Receptor = specialised cell/protein that detects changes in the environment and initiates a response
• Coordinator = central point of a control system that processes information from receptors and sends signals to effectors
• Effector = muscle/gland/organ that carries out a response to restore conditions to optimum level
• Feedback mechanism = process in which the output of a system influences/regulates its own activity
• Negative feedback = mechanism that counters a change in a physiological conditions, restoring it back to the set point
• Positive feedback = mechanism that amplifies a change in a physiological conditions, often leading to a specific outcome
• Vasodilation = widening of blood vessels to increase blood flow and heat loss, aiding in thermoregulation
• Glucagon = hormone secreted by alpha cells in the pancreas that raises blood glucose levels
• Insulin = hormone secreted by beta cells in the pancreas that lowers blood glucose levels
• Target cells = specific cells with receptors that bind to particular hormones, triggering a specific response
• Second messenger model = mechanism where a hormone binds to a receptor, triggering the production of a messenger molecule
• Islet of Langerhans = clusters of hormone-secreting cells in the pancreas containing alpha cells and beta cells
• Alpha cells = cells that secrete glucagon to increase blood glucose levels
• Beta cells = cells that secrete insulin to lower blood glucose levels
• Glycogenesis = process of converting glucose into glycogen for storage in the liver and muscle cells
• Glycogenolysis = breakdown of glycogen into glucose in the liver and muscles to increase blood glucose levels
• Gluconeogenesis = production of glucose from non-carbohydrate sources like amino acids and glycerol
• Adrenaline = hormone released by the adrenal glands in response to stress, increasing blood glucose levels
• Type I diabetes = conditions caused by autoimmune destruction of beta cells, resulting in little to no insulin production
• Type II diabetes = condition where cells become resistant to insulin or insufficient insulin in produced
• Glycoprotein = protein with carbohydrate chains attached, playing roles in cell signalling and recognition
• Biosensors = devices that use biological molecules to detect substances such as glucose in blood
• Osmoregulation = control of water and solute levels in the blood to maintain osmotic balance
• Nephron = functional unit of the kidney responsible for filtering blood, reabsorbing substances and forming urine
• Fibrous capsule = tough outer membrane that protects the kidney and maintains its structure
• Cortex = outer region of the kidney containing the glomeruli and proximal convoluted tubules
• Bowman's capsule = structure in the nephron that collects filtrate from the glomerulus during ultrafiltration
• Medulla = inner region of the kidney containing the loop of Henle and collecting ducts
• Loop of Henle = U-shaped structure in the nephron that establishes a concentration gradient in the medulla
• Proximal convoluted tubule = section of the nephron that regulates reabsorption of water, ions and glucose
• Podocytes = specialised cells lining the Bowman's capsule that create filtration slits
• Distal convoluted tubule = portion of the nephron that regulates ion balance and pH under the influence of hormones
• Collecting duct = final part of the nephron where water reabsorption is regulated by ADH
• Afferent arteriole = blood vessel that brings blood to the glomerulus for filtration
• Glomerulus = capillary network in the nephron where ultrafiltration occurs
• Efferent arteriole = blood vessel carrying blood away from the glomerulus, maintaining pressure for filtration