2025/l 2026l Update)l Essentiall Biologyl IIl
W/Labl |l Questionsl &l Answers|l Gradel A|l
100%l Correctl (Verifiedl Solutions)-l
Portagel Learning
Q:l Whatl isl thel functionl ofl thel semilunarl valves?
Answer:
Thesel valvesl functionl oppositel ofl thel AVl valvesl inl thatl theyl arel pushedl openl asl thel
ventriclesl contract.l Asl thel ventriclesl beginl tol relax,l thel bloodl thatl isl remainingl inl thel
aortal andl pulmonaryl arteriesl pushl thel semilunarl valvesl closedl tol preventl bloodl froml
flowingl backl intol thel ventriclesl afterl contraction
Q:l Wherel inl thel circulatoryl systeml isl bloodl pressurel thel greatest?
Answer:
Thel pressurel isl greatestl inl thel aortal andl arteries,l andl thisl pressurel propelsl thel bloodl
throughl thel vessels
Q:l ________l appearl asl dark,l verticall linesl thatl arel perpendicularl tol thel horizontall
thinl andl thickl filaments.l Positionedl verticallyl inl thel middlel ofl eachl sarcomerel isl thel
________,l whichl servesl asl thel attachmentl pointl forl thel thickl filaments.
Answer:
Z-lines;l M-line
,Q:l Whichl vesselsl carryl deoxygenatedl bloodl tol thel heartl inl thel systemicl circulation?
Answer:
Veins
Q:l Whichl ofl thel followingl ionsl isl anl importantl regulatoryl ionl forl musclel contraction?
Answer:
Calcium
Q:l Depolarizationl ofl thel post-synapticl membrane,l typicallyl causedl byl sodiuml ions,l isl
calledl anl _________l post-synapticl potential,l whereasl hyperpolarizationl ofl thel post-
synapticl membranel isl calledl anl ____________l post-synapticl potential.
Answer:
excitatory;l inhibitory
Q:l Faintingl mechanisml isl activatedl whenl receptorsl inl thel brainl andl neckl detectl anl
acutel dropl inl bloodl pressure
Answer:
Ifl receptorsl inl thel brainl andl thel largel vesselsl ofl thel neckl detectl al dropl inl thel
pressurel greaterl thanl al normall deviation,l thel faintingl mechanisml isl activated
Q:l Whichl ofl thel followingl refersl tol thel volumel ofl bloodl thatl isl pumpedl froml eachl
ventriclel perl minute?
,Answer:
Cardiacl output
Q:l Whatl occursl duringl thel restingl phasel ofl anl actionl potential?
Answer:
Duringl thel restingl phase,l thel gatedl Na+l andl K+l channelsl arel bothl closed,l andl thel
membranel potentiall isl aroundl -70l mV
Q:l Whatl typel ofl shiftl inl al membrane'sl potentiall canl resultl froml positivel ionsl leavingl
thel celll orl negativel ionsl flowingl intol thel cell?
Answer:
Hyperpolarization
Q:l Truel orl False;l Ifl false,l explainl whyl thel statementl isl false:l Thel SAl nodel cannotl
producel electricall impulsesl withoutl stimulationl froml neurons.
Answer:
False;l Thel SAl nodel canl producel electricall impulsesl withoutl stimulationl froml neurons
Q:l Whatl isl anatomy?
Answer:
Anatomyl encompassesl thel physicall forml ofl anl organism
Q:l Whatl doesl thel terml polarizationl mean?
, Answer:
Polarizationl refersl tol thel statel inl whichl therel isl al differencel inl thel chargel orl voltagel
acrossl thel membrane,l namely,l thatl thel overalll chargel insidel thel neuronl (negative)l isl
differentl froml thatl outsidel ofl thel neuronl (positive)
Q:l Whatl isl al twitch?
Answer:
Eachl timel al somaticl motorl neuronl sendsl anl actionl potential,l eachl musclel fiberl ofl thel
motorl unitl willl contract.l Onel cyclel ofl contractionl andl completel relaxationl inl responsel
tol al singlel stimulusl isl calledl al twitch
Q:l Truel orl False;l Ifl false,l explainl whyl thel statementl isl false:l Acetylcholinel worksl
thel samel wayl atl thel neuromuscularl junctionl andl onl cardiacl cells.
Answer:
False;l Thel functionl ofl AChl atl thel synapsesl ofl cardiacl cellsl isl completelyl differentl thanl
itsl model ofl actionl atl thel neuromuscularl junction.l Withinl cardiacl muscle,l AChl hasl anl
inhibitoryl effectl andl doesl notl bindl tol ligand-gatedl receptorsl ofl thel cardiacl cells
Q:l Inl cardiacl musclel tissue,l ________l relayl andl coordinatel electricall informationl andl
thenl sharel itl withl adjacentl cells.
Answer:
Intercalatedl disks
Q:l Explainl howl inactivatingl enzymesl clearl neurotransmittersl froml thel synapticl cleft.