Kin 2YY3 Test 1 Questions With Complete Solutions
Additional functions of CVS Correct Answers 1. Immunity
(ex. WBC's & antibodies)
2. Tissue repair (ex. platelets)
3. Body temperature (ex. release excessive heat through sweat)
At what rate do the purkinje fibers beat? Could you live with
just these being the pacemaker cells? Correct Answers 25-30
beats/minute. No, this heart rate is not really enough to sustain
our body - it's too slow to meet the oxygen and fuel demands of
our body. If people have something wrong with their SA node or
their AV node, they would typically get an artificial pacemaker.
Describe 3 ways that specialized cardiac cells control the
movement of an action potential through the heart. Correct
Answers 1. Changing number of gap junctions (fewer=slower
signal; more=faster signal) 2. Different ions present in
sarcolemma
3. Different diameter (small=slow signal; big=fast signal)
Describe the endocardium. Correct Answers Lines chambers
& valves; covers trabecular carneae (extension of myometrium)
in ventricles, pectinate muscles in anterior wall of right atrium,
and auricles in both atria
Describe the epicardium. Correct Answers Visceral layer of
serous pericardium; simple squamous epithelium, loose CT, &
adipose tissue
,Describe the myocardium. Correct Answers Cardiac muscle;
makes up bulk of heart; thicker in ventricles because stronger
forces of contraction there
How are cardiac muscle fibres different from skeletal muscle
fibres? Correct Answers • Don't run entire length of muscle
• Connect together in series, so are branching
• Fewer nuclei that are centrally located
• Fewer myofibrils that aren't as highly organized (still some
striations/bands. Also, having myofibrils means there's still
actin, myosin, sarcomeres, sarcolemma, cross-bridge cycling,
sliding filament theory)
• Fewer transverse tubules
• More mitochondria, needs more energy
• Intercalated discs - folds in sarcolemma holding cells together
(connect to other cells like puzzle)
• Desmosomes within intercalated discs - plasma membrane
(sarcolemma) structures that staple cells together when muscle
fibres contracting
• Gap junctions - electrical synapse, direct movement of ions
from one cell to neighbouring cell
• T tubules larger and less frequent
• T tubules located at Z discs instead of near SR, which is not as
organized
• Less efficient in contracting fast
• No terminal cisternae
How do autorhythmic cells reach threshold? What is this
threshold called? Correct Answers On their membrane are
non-gated sodium channels that allow sodium to constantly
move into cell and get the cell closer and closer to threshold.
, This change in membrane potential is responded to by the
opening of calcium voltage-gated channels and threshold is
slowly reached once calcium enters cell (slow since K+ channels
still closing). This threshold is called pacemaker threshold.
How long is the PQ interval and what event does it depict?
Correct Answers 0.16 seconds. Start of atrial excitation to start
of
ventricular excitation.
How long is the QT interval and what event does it depict?
Correct Answers 0.36 seconds. Start of ventricular
depolarization to end of ventricular repolarization.
If you didn't have a working SA node, what would our heart rate
be set to by the AV node? Correct Answers 60-70
beats/minute
List the 3 sulci of the heart. Correct Answers Coronary sulcus,
anterior interventricular sulcus, posterior interventricular sulcus
List the 3 types of circulation and what part of the body they are
going through. Correct Answers 1. Pulmonary circulation:
through lungs
2. Systemic circulation: through the body (upper systemic
circulation is tissues of head, neck, and upper limbs; lower
systemic circulation is tissues of thorax, abdomen, and lower
limbs)
3. Coronary circulation: through the heart
Additional functions of CVS Correct Answers 1. Immunity
(ex. WBC's & antibodies)
2. Tissue repair (ex. platelets)
3. Body temperature (ex. release excessive heat through sweat)
At what rate do the purkinje fibers beat? Could you live with
just these being the pacemaker cells? Correct Answers 25-30
beats/minute. No, this heart rate is not really enough to sustain
our body - it's too slow to meet the oxygen and fuel demands of
our body. If people have something wrong with their SA node or
their AV node, they would typically get an artificial pacemaker.
Describe 3 ways that specialized cardiac cells control the
movement of an action potential through the heart. Correct
Answers 1. Changing number of gap junctions (fewer=slower
signal; more=faster signal) 2. Different ions present in
sarcolemma
3. Different diameter (small=slow signal; big=fast signal)
Describe the endocardium. Correct Answers Lines chambers
& valves; covers trabecular carneae (extension of myometrium)
in ventricles, pectinate muscles in anterior wall of right atrium,
and auricles in both atria
Describe the epicardium. Correct Answers Visceral layer of
serous pericardium; simple squamous epithelium, loose CT, &
adipose tissue
,Describe the myocardium. Correct Answers Cardiac muscle;
makes up bulk of heart; thicker in ventricles because stronger
forces of contraction there
How are cardiac muscle fibres different from skeletal muscle
fibres? Correct Answers • Don't run entire length of muscle
• Connect together in series, so are branching
• Fewer nuclei that are centrally located
• Fewer myofibrils that aren't as highly organized (still some
striations/bands. Also, having myofibrils means there's still
actin, myosin, sarcomeres, sarcolemma, cross-bridge cycling,
sliding filament theory)
• Fewer transverse tubules
• More mitochondria, needs more energy
• Intercalated discs - folds in sarcolemma holding cells together
(connect to other cells like puzzle)
• Desmosomes within intercalated discs - plasma membrane
(sarcolemma) structures that staple cells together when muscle
fibres contracting
• Gap junctions - electrical synapse, direct movement of ions
from one cell to neighbouring cell
• T tubules larger and less frequent
• T tubules located at Z discs instead of near SR, which is not as
organized
• Less efficient in contracting fast
• No terminal cisternae
How do autorhythmic cells reach threshold? What is this
threshold called? Correct Answers On their membrane are
non-gated sodium channels that allow sodium to constantly
move into cell and get the cell closer and closer to threshold.
, This change in membrane potential is responded to by the
opening of calcium voltage-gated channels and threshold is
slowly reached once calcium enters cell (slow since K+ channels
still closing). This threshold is called pacemaker threshold.
How long is the PQ interval and what event does it depict?
Correct Answers 0.16 seconds. Start of atrial excitation to start
of
ventricular excitation.
How long is the QT interval and what event does it depict?
Correct Answers 0.36 seconds. Start of ventricular
depolarization to end of ventricular repolarization.
If you didn't have a working SA node, what would our heart rate
be set to by the AV node? Correct Answers 60-70
beats/minute
List the 3 sulci of the heart. Correct Answers Coronary sulcus,
anterior interventricular sulcus, posterior interventricular sulcus
List the 3 types of circulation and what part of the body they are
going through. Correct Answers 1. Pulmonary circulation:
through lungs
2. Systemic circulation: through the body (upper systemic
circulation is tissues of head, neck, and upper limbs; lower
systemic circulation is tissues of thorax, abdomen, and lower
limbs)
3. Coronary circulation: through the heart
