UNIT 1 PHYSIO

Homeostasis

Maintenance of relatively stable conditions within the internal environment regardless of the external environment.

Nervous System

System responsible for rapid adjustments to maintain homeostasis.

Endocrine System

System that makes gradual adjustments to maintain homeostasis.

Negative Feedback

Mechanism that maintains homeostasis by correcting deviations from a set point.

Set Point

Specific parameter of the body, like temperature at 37 C.

Sensors

Monitor the internal environment and send information to the control center.

Control Centre

Integrates information from sensors and develops a plan to restore homeostasis.

Effector

Organ or organ systems that respond to the control center's plan.

Variable

The internal condition regulated by the negative feedback system.

Positive Feedback

Mechanism that does not maintain homeostasis, amplifying responses until a stimulus is removed.

Extracellular Fluid (ECF)

Fluid found outside the cell, including blood plasma and interstitial fluid.

Intracellular Fluid (ICF)

Fluid that is contained within the cell.

Ions

Charged particles, such as Na+, Cl-, Ca++, and K+, that have different concentrations inside and outside the cell.

Selective Permeability

Property of cell membranes that allows certain substances to pass while blocking others.

Membrane Potential

Charge difference across a cell membrane that allows movement of ions.

Equilibrium Potential

The electrical potential needed to prevent an ion from moving down its concentration gradient.

Diffusion

Process by which molecules move from an area of high concentration to low concentration.

Facilitated Diffusion

Movement of molecules across a membrane via protein carriers without energy.

Active Transport

Process that moves molecules against their concentration gradient requiring energy.

Osmosis

Net movement of water across a semipermeable membrane down its concentration gradient.

Tonicity

Effect of a solution on water movement across a cell membrane.

Isotonic Solution

Solution with an osmolarity equal to that of the cell, leading to no net water movement.

Hypotonic Solution

Solution with lower osmolarity than inside the cell, causing swelling.

Hypertonic Solution

Solution with higher osmolarity than inside the cell, causing shrinkage.

Physiology

Study of the functions of living organisms and their parts, focusing on internal control mechanisms.