a6

Question 0

saturation

Answer 0

characteristic feature of protein mediated transport processes – by increasing the concentration of the molecules to be transported, increase of the transport speed increases less and less as most of the transporter molecules tend to be occupied after a certain concentration

Question 1

sarcoplasmic reticulum

Answer 1

similar to the smooth endoplasmic reticulum; large internal store of Ca++ ions in the muscle fibers

Question 2

scalar electrocardiogram

Answer 2

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 3

Schwann cell

Answer 3

glia cell forming myelin sheath around axons at the periphery

Question 4

second messenger

Answer 4

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

Question 5

secondary structure of proteins

Answer 5

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

Question 6

semilunar valves

Answer 6

valves at the orifice of the aorta and pulmonary artery

Question 7

semipermeable membrane

Answer 7

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

Question 8

septum

Answer 8

muscular tissue separating the left and right atria and ventricle

Question 9

side chain

Answer 9

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

Question 10

sinoatrial node

Answer 10

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

Question 11

sliding filament hypothesis

Answer 11

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

Question 12

space constant

Answer 12

externally induced and electrotonically conducted potential changes in the membrane decrease to 37% (1/e) after traveling a distance equal to the space constant

Question 13

specificity

Answer 13

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

Question 14

spirometer

Answer 14

device to measure lung volumes and aspects of breathing

Question 15

Starling’s hypothesis

Answer 15

theory to explain the production and absorption of interstitial fluid

Question 16

strength (energy) of a bond

Answer 16

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

Question 17

sucrose

Answer 17

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

Question 18

summation

Answer 18

in time and in space; adding up of the effects of two synaptic potentials occurring at the same synapse with short delay or in neighboring synapses concurrently

Question 19

surface active agent

Answer 19

lamphipathic molecule bearing both hydrophilic and hydrophobic groups

Question 20

surface active substance (amphipathic~, detergent~)

Answer 20

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

Question 21

surfactant

Answer 21

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

Question 22

systole

Answer 22

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

Question 23

tercier structure of proteins

Answer 23

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

Question 24

tetanic contraction

Answer 24

uninterrupted muscular contraction caused by high-frequency motor impulses

Question 25

thrombosis

Answer 25

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

Question 26

tidal volume

Answer 26

volume of air moved during a relaxed inspiration or expiration

Question 27

tight junction

Answer 27

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

Question 28

time constant

Answer 28

time required for an externally induced potential change in the membrane to decrease to 37% (1/e) of the original potential

Question 29

trace elements

Answer 29

elements needed in a very low concentration for the normal functioning of the organism (Fe, I, Zn, Co, Mn, etc.) their total amount is about 0.01%

Question 30

trachea

Answer 30

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

Question 31

tricuspid valve

Answer 31

valve between the right atrium and ventricle

Question 32

triglycerides

Answer 32

lipid molecules composed of three fatty acid residues esterified to glycerol

Question 33

T-tubules

Answer 33

invagination of the sarcolemma, carrying excitation to the sarcoplasmic reticulum

Question 34

turbulent flow

Answer 34

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

Question 35

unipolar neuron

Answer 35

nerve cell with only one process

Question 36

unsaturated fatty acid

Answer 36

fatty acid containing one or more double bonds

Question 37

Valsalva’s maneuver

Answer 37

sustained expirational effort against a closed glottis

Question 38

van der Waals forces

Answer 38

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

Question 39

vena cava

Answer 39

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 40

ventilation

Answer 40

air exchange between the lungs and the ambient air

Question 41

venule

Answer 41

– small vessel connecting the capillaries to veins

Question 42

vesicle

Answer 42

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

Question 43

viscosity

Answer 43

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

Question 44

vital capacity

Answer 44

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