Ch 4 Cell Metabolism Vet Tech A&P1 (Material NOT on Ch 3, 4 exam has been removed in this version)

Normal Hydration

Consuming the same amount of water that is lost.

Metabolic water

Water made inside of cells during chemical reactions.

Insensible water loss

Water lost through breathing.

Intracellular fluid

Fluid located inside cells.

Extracellular fluid

Fluid located outside cells.

Intravascular fluid

Fluid located inside blood vessels.

Interstitial fluid

Fluid directly surrounding cells.

Solutes

Solids that are dissolved in water.

Electrolytes

Particles in body fluids capable of conducting an electrical current.

Cations

Positively charged ions.

Anions

Negatively charged ions.

Electrolyte concentrations

Expressed in meq/L.

Acidity

More free H+ ions in a solution equals more acidity.

pH of pure water

7 (neutral).

pH of blood

7.4.

pH of gastric juice

Below 7 (pH 2).

Alkalinity

More free OH- ions in a solution, the more basic or alkaline.

pH of bleach

Above 7.

Osmolality

Measurement of solute concentration in fluid.

High osmolality

Indicates high concentration of solutes.

Serum osmolality tests

Used to assess hydration status.

Hyperglycemia

High blood glucose, sugar, simple blood test

Isotonic Fluid

Same solute level as normal blood; extracellular fluid has same concentration of dissolved substances as intracellular fluid

Example of Isotonic Fluid

0.9% NaCl (normal saline)

Hypotonic Fluid

Solute level is less than that of blood; cytoplasm of the cell is more concentrated (more solute) than the extracellular fluid

Osmolality in Hypotonic Fluid

Osmolality is greater than that of blood cells; extracellular fluid is more concentrated than the cytoplasm

Movement of Water in Hypotonic Fluid

Water flows to the area with most solute, into the cell, causing it to swell and possibly to break

Edema

Abnormal, excess accumulation of fluid in tissue; common sign of abnormal movement of fluid from vascular space into interstitial space

Pulmonary Edema

Fluid moves into lungs

Cutaneous Edema

Fluid moves into interstitial space, generally into gravity-dependent areas or into the abdomen

Crystalloid

Composed of sterile water rich with electrolytes; isotonic, hypotonic or hypertonic; solutes are small and able to cross vascular wall

Colloid

Heavy molecules suspended in isotonic crystalloid; solutes too large to cross vascular wall

Fluid therapy phases

Administered in three phases: Resuscitation during shock, Replacement when dehydrated, Maintenance during elective surgical procedures

Membrane Processes

Absorption of nutrients or excretion of waste through plasma membrane may occur with or without using energy (ATP) from the cell

Passive processes

Does NOT use ATP

Active processes

DOES use ATP

Membrane permeability

Freely permeable (small, hydrophobic, moves quickly through), Selectively permeable (allows some things through but not others), Impermeable (not permeable, needs a protein 'doorway')

Passive Diffusion

Movement of molecules from higher to lower concentration; moves WITH the concentration gradient

Facilitated Diffusion

Movement of molecules from higher to lower concentration; moves WITH the concentration gradient

Selective carrier proteins

Assist in movement of molecules from higher to lower concentration.

Factors determining molecule passage

Molecular size (small), lipid solubility (hydrophobic), molecular charge (neutral).

Osmosis

Movement of water through a semipermeable membrane from dilute solution to a more concentrated one.

Osmotic pressure

The pressure required to prevent the flow of water across a semipermeable membrane.

Equilibrium

Objective is for movement of water to achieve the same concentration on both sides of a semipermeable membrane.

Oncotic Pressure

The difference between osmotic pressure of blood and osmotic pressure of interstitial fluid or lymph.

Filtration

Based on a pressure gradient; liquids may be pushed through a membrane if pressure on one side is greater.

Active membrane processes

Movement of molecules from low concentration to high concentration across the cell membrane using energy (ATP).

Active transport

Some amino acids and ions rely on a carrier protein and energy (ATP) to move through the plasma membrane.

Na/K Pump

An example of active transport that moves sodium and potassium ions across the plasma membrane.

Cytosis

Mechanism for bringing nutrients into the cell and ejecting waste.

Endocytosis

Transports large particles or liquids into the cell by engulfing them.

Exocytosis

Cells export intracellular substances into the extracellular space.

Phagocytosis

Cell 'eats'; cells engulf solid material.

Pinocytosis

Cell 'drinks'; cells engulf liquid material.

Receptor-mediated endocytosis

A very specific process where ligands bind to specific receptors, forming a vesicle.

Hydrostatic pressure

The pressure exerted by a fluid at equilibrium due to the force of gravity.

Subcutaneous edema

Swelling caused by excess fluid trapped in the body's tissues.

Ascites

Accumulation of fluid in the peritoneal cavity.

Vesicles

Substances packaged by the endoplasmic reticulum and Golgi body for transport.