Part 6

Question 1

Scalar elcetrocardiogram

Answer 1

signal measured in any of the Einthoven leads, corresponding to the projection of the electrical vector of the heart onto a line connecting two electrodes, thus transforming the vector into a scalar variable

Question 2

Schwann cell

Answer 2

glia cell forming myelin sheet around axons at the periphery

Question 3

Second messengers

Answer 3

small molecules whose concentration changes after the first messenger (signal) attaches to the membrane receptor

Question 4

Secondary structure of proteins

Answer 4

formation of regular structures (a-helix, b-sheet) in the peptide chain stabilized by H-bonds

Question 5

Semilunar valves

Answer 5

valves at the orifice of the aorta and pulmonary artery

Question 6

Semipermeable membrane

Answer 6

membrane separating two solutions and limiting the penetration of some solvents from one side to the other

Question 7

Septum

Answer 7

muscular tissue separating the left and right atria and ventricle

Question 8

Side chain

Answer 8

a group bond to the -carbon atom of amino acids; amino acids are distinguished by the chemical composition of this group

Question 9

Sinoatrial node

Answer 9

specialized cardiac tissue in the right atrium acting as the pacemaker of the heart

Question 10

Sliding filament hypothesis

Answer 10

generally accepted theory explaining muscle contraction by sliding of actin and myosin filaments on each other

Question 11

Space constant

Answer 11

externally induced and electrotonically conducted potential changes in the membrane decrease to 37% after traveling a distance equal to the space constant

Question 12

Specificity

Answer 12

due to its spatial structure, a receptor, enzyme or transporter molecule can only bind a limited number of substrate molecules

Question 13

Spirometer

Answer 13

device to measure lung volumes and aspects of breathing

Question 14

Starling´s hypothesis

Answer 14

theory to explain the production and absorption of interstitial fluid

Question 15

Strength (energy) of a bond

Answer 15

energy released during the formation of the given bond between atoms - this energy is needed to break apart the atoms

Question 16

Sucrose

Answer 16

disaccharide built up by glucose and fructose; it its the most common commercially available sweetener

Question 17

Summation

Answer 17

he process by which multiple or repeated stimuli can produce a response in a nerve, muscle, or other part that one stimulus alone cannot produce.

Question 18

Surface active agent

Answer 18

amphipathic molecule bearing both hydrophilic and hydrophobic groups

Question 19

Surface active substance

Answer 19

its molecules possess both hydrophilic and hydrophobic parts; they tend to line up at the boarder separating two fieerent phases (lipid-water, water-air etc) with the hydrophilic and hydrophobic parts located in the appropriate phase

Question 20

Surfactant

Answer 20

surface active agent lining the inner surface of the alveoli and decreasing surface tension

Question 21

Systole

Answer 21

the portion of the heart beat when the heart muscle is contracting

Question 22

Tercier structure of proteins

Answer 22

3D, spatial form of the protein chain stabilized by weak-interactions (electrostatic, van der Waals)

Question 23

Tetanic contraction

Answer 23

uninterrupted muscular contraction caused by high-frequency motor impulses

Question 24

Thrombosis

Answer 24

blockade of a vessel due to a blood clot formed in the vessel

Question 25

Tidal volume

Answer 25

volume of air moved during a relaxed inspiration or expiration

Question 26

Tight junction

Answer 26

area of membrane fusion between adjoining cells that prevents the passage of extracellular material between the cells

Question 27

Time constant

Answer 27

time required for an externally induced potential change in the membrane to decrease to 37% of the original potential

Question 28

Trace elements

Answer 28

elements needed in a very low concentration for the normal functioning of the organism

Question 29

Trachea

Answer 29

large respiratory passageway connecting the pharynx with the bronchi of the vertebrate lung

Question 30

Tricuspid valve

Answer 30

valve between the right atrium and ventricle

Question 31

Triglycerides

Answer 31

lipid molecules composed of three fatty acid residues esterified to glyceorl

Question 32

T-tubules

Answer 32

invagination of the sarcolemma, carrying excitation to the sarcoplasmic reticulum

Question 33

Turbulent flow

Answer 33

a flow pattern in which particles of the fluid move irregularly in all directions of the space

Question 34

Unipolar neuron

Answer 34

nerve cell with only one process

Question 35

Unsaturated fatty acid

Answer 35

fatty acid containing one or more double bonds

Question 36

Valsalva´s maneuver

Answer 36

sustained expirational effort against a closed glottis

Question 37

van der Waals forces

Answer 37

relatively weak attraction between atoms and molecules with hydrophobic properties due to the random fluctuation of the electron clouds

Question 38

Vena cava

Answer 38

empty vein; large veins returning from the body to the right atrium were named vena cavae, because they were found empty in hanged persons dissected during medieval times

Question 39

Ventilation

Answer 39

air exchange between the lungs and the ambient air

Question 40

Venule

Answer 40

small vessel connecting the capillaries to veins

Question 41

Vesicle

Answer 41

small, spherical compartment in the cell surrounded by a membrane (e.g. synaptic vesicle)

Question 42

Viscosity

Answer 42

physical property of fluids that determines the ease with which the layers of a fluid move past each other

Question 43

Vital capacity

Answer 43

the maximum volume of air that can be inhaled to or exhaled from the lungs