Basic Principles of Physiology I Flashcards Preview

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Flashcards in Basic Principles of Physiology I Deck (25)
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1

Body composition of water for men, women, and neonates

Men: 60%
Women: 50% (reflects increased body fat)
Neonates: 70%

2

Body fluids can be divided into two categories based on their location relative to the cell membrane

Intracellular (40% of body weight) and extracellular fluid (20% of body weight)

3

Extracellular fluid is composed of what?

Interstitial fluid (15%): present in the spaces between cells
Blood plasma (5%)

4

Normal daily intake of water

2.5L
1.5L is excreted as urine, 100mL is lost in sweat, and 100mL is present in feces

5

Average blood volume

5L (3L of plasma and 2L of erythrocytes)

6

Normal hematocrit (HCT) for men/women

45% for men and postmenopausal women
38% for menstruating women +/-5%

7

An unequal distribution of ions results in the establishment of ____ differences across cell membranes

voltage

8

Trauma is associated with progressive loss of...?

Potassium through the kidneys d/t increased secretion of vasopressin, and in part (depending on surgery) due to NGT suctioning and direct K+ loss

9

Movement of water (solvent molecules) across a semipermeable membrane from a compartment of lower solute concentration to an area of higher solute concentration

osmosis

10

D5W

Initially isotonic when infused, but glucose is metabolized so the net effect is that of infusing a HYPOtonic solution

11

LR in 5% dextrose

Initially HYPERtonic but as glucose is metabolized, the solution becomes less hypertonic

12

The role of crystalloids in restoring perfusion in microcirculation

After 20-30m, an estimated 75-80% of isotonic NS or LR solution will have distributed outside the confines of the circulation, thus limiting the efficacy of these solutions in treating HYPOvolemia

13

Ratio of extracellular to intracellular fluid

In infants, this is greater than adults (dehydration develops more rapidly and is often more severe in the young)

14

Cell membrane and solubility

Each cell is surrounded by a lipid bilayer that acts as a permeable barrier, allowing the cell to maintain a cytoplasmic composition different from the extracellular fluid. Lipid bilayers are nearly impermeable to water-soluble substances (ions, glucose, etc.). Conversely, fat-soluble substances (steroids) and gases readily cross cell membranes.

15

Simple diffusion

O2, CO2, and nitrogen move through cell membranes by simple diffusion

16

Exocytosis

Neurotransmitters are ejected from cells via exocytosis, a process that requires Ca++ and resembles endocytosis in reverse.

17

Na/K ATPase

ATP-dependent sodium and potassium transporter on the cell membrane that ejects three sodium ions from the cell in exchange for the import of two potassium ions

18

Ion channels

Transmembrane proteins that generate electrical signals in the brain, nerve, heart, and skeletal muscles

19

Phagocytosis and pinocytosis

Phagocytosis: Ingestion of solid particles
Pinocytosis: Ingestion of dissolved particles

20

Genes encoding the protein ion channels may be defecting leading to...

Diseases such as cystic fibrosis (chloride channel defect) and long QT syndrome (mutant K channels or less commonly Na channels)

21

Nucleus

Made up of 46 chromosomes except for the nucleus of an egg cell, which contains 23

22

Cytoplasm

Consists of water, electrolytes, and proteins (including enzymes, lipids, carbs) and also contains numerous organelles

23

Mitochondria

Power-generating unit of cells containing both enzymes and substrates of the tricarboxylic acid cycle (Krebs cycle) and the electron transport chain

24

Endoplasmic Reticulum (ER)

A complex lipid bilayer that folds and creates vesicles in the cytoplasm. The portion of the membrane containing ribosomes is the RER, and the part that lacks is the SER. The smooth portion of the ER functions in the synthesis of lipids, metabolism of carbs, and other enzymatic processes. The sarcoplasmic reticulum is found in muscle cells, where it serves as a reservoir for Ca++

25

5 major types of protein ion channels

Ca++, Na+, Nonselective, Cl-, and K+
*Flow of ions through these channels (Ca++ and Na+ IN, K+ OUT) determines the transmembrane potential