Lab Quiz 2 Flashcards
twitch
single muscle contraction
tropomyosin
protein molecule that prevents myosin filaments from coming in contact with actin filaments
substance necessary for functioning of enzymes involved in muscle contraction
magnesium
troponin
protein complex that calcium binds to, causing tropomyosin to slide out of the way, and the myosin to come in contact with actin
type I muscle fibers
- slow-twitch
- aerobic
- good endurance
- lots of mitochondria
- lots of myoglobin
- many capillaries
- relatively small
- smaller motor units
type II muscle fibers
- fast-twitch
- anaerobic
- fatigue easily
- few mitochondria
- little myoglobin
- few capillaries
- larger in diameter
- stronger stimulus to cause recruitment
motor unit
somatic motor neuron and all of the muscle fibers it innervates
motor unit summation
recruitment of motor units
wave or temporal summation
series of contractions that build on each other
tetanus
when stimuli are delivered so rapidly there is no time for relaxation, so that the muscle is in a smooth, sustained contraction
what are summation and tetanus due to?
an increase in the frequency of stimulation
what is summation of motor units due to?
increased strength (amplitude) of each individual stimulus
lactic acid (lactate)
- product of anaerobic respiration
- associated with fatigue
- lactic acid accumulates in muscle –> pH drops –> reduced enzyme activity
- short-term fatigue
- lactic acid is quickly removed from the muscle and taken up to the liver for gluconeogenesis (converted back to glucose)
products of aerobic respiration
CO2 and H2O
what is fatigue during endurance exercise associated with?
depletion of glycogen
instrument that measures the force of muscle contraction in kg/force
hand dynamometer
glycerination process
disrupts the troponin/tropomyosin complex that otherwise blocks the myosin binding sites; therefore, no calcium is needed to induce contraction
another name for posterior
caudal
another name for anterior
rostral
plane that divides the left from the right
sagittal plane
plane that divides front from back
frontal (or coronal) planes
plane that divides top and bottom
horizontal plane
meninges of brain
- dura mater
- arachnoid layer
- pia mater
brain stem structures
- pons
- medulla
- cerebellum
cerebral aqueduct
connects third and fourth ventricle
structures of ventral surface of brain
- pair of olfactory bulbs (one under each lobe of the frontal cortex)
- optic nerves
- optic chiasm
- optic tract
- longitudinal fissure
- oculomotor (III) nerve
- IV ventricle
superior and inferior colliculi
- part of midbrain
- collectively known as the Tectum
commissures
- band of fibers that connects the two sides of the CNS
- largest of all commissures is the corpus callosum
tree of life
- cerebellum
- arbor vitae
basal ganglia
- putamen
- globus pallidus
- caudate nucleus
two types of control in heart activity
- autonomic nervous system
-
intrinsic conduction (nodal) system
- consists of specialized noncontractile myocardial tissue
- ensures heart muscle depolarizes in an orderly and sequential manner
components of intrinsic conduction system
-
sinoatrial node
- in right atrium just inferior to the entrance to the superior vena cava
-
atrioventricular node
- in the lower atrial septum at the junction between the atria and ventricles
-
AV bundle (Bundle of His) and right and left bundle branches
- in interventricular septum
-
purkinje fibers
- within muscle bundles of the ventricular walls
- network is much denser and more elaborate in the left ventricle
P wave
small wave that indicates depolarization of the atria immediately before atrial contraction (systole)
waves of ECG
deflection waves
QRS complex
- results from ventricular depolarization
- precedes ventricular systole
- repolarization of the atria occurs, but is obscured
T wave
- results from currents during ventricular repolarization (relaxation of the muscle, or diastole)
what does an ECG show?
- voltage and time
- records electrical events occurring in relatively large amounts of muscle tissue, not the activity of nodal tissue
P-R (P-Q) interval
- represents the time between the beginning of atrial depolarization and ventricular depolarization
- 0.16 to 0.18 sec
what might a long P-R interval suggest?
- a partial AV heart block caused by damage to the AV node
what happens in a total heart block?
- no impulses are transmitted thorugh the AV node
- the atria and ventricles beat independently of one another - the atria at the SA node rate and the ventricles at the intrinsic rate, which is considerably lower
normal QRS interval range
0.04-0.12 sec
what does a prolonged QRS interval indicate?
a right or left bundle branch block in which one ventricle is contracting later than the other
Q-T interval
- 0.3-0.44 sec
- period from the beginning of ventricular depolarization through repolarization
- includes time of ventricular contraction (S-T)
fibrillation
- a condition of rapid uncoordinated heart contractions which makes the heart useless as a pump
- may be caused by prolonged tachycardia
leads for ECG
- 12 standard leads
- 3 are bipolar leads that measure the voltage difference between the arms, or an arm and a leg
- 9 other unipolar leads
Einthoven’s triangle
- clinically assumed that the heart lies in the center of a triangle with sides of equal lengths, and that the recording connections are made at the vertices of that triangle
standard limb leads
record the voltages generated in the extracellular fluids surrounding the heart
lead I
- RA-LA
- connects right and left arms
- most sensitive to electrical activity spreading horizontally across the heart
lead II
- RA-LL
- right arm and left leg
- records activity along the vertical axis (from the base of the heart to its apex), but from different orientations
lead III
- LA-LL
- records activity along the vertical axis (from the base of the heart to its apex), but from different orientations
Einthoven’s law
the sum of the voltages of leads I and III equals that in lead II
how to compute heart rate
- measure the distance (mm) from the beginning of one QRS complex to the beginning of the next QRS complex
- mm * 0.04 sec/mm = sec/beat
- then to find beats/min:
- (1 / sec/beat) * 60 sec/min
- then to find beats/min:
normal blood pressure
- 95-135 for systolic
- 50-90 for diastolic
auscultatory method
vibrations of the arterial wall when the normal circular form of the artery is, in the compression area, more or less distorted by external pressure
Korotkoff sounds
characteristic sounds as blood flow returns to normal (while taking BP)
five phases during lowering of the external pressure from above the obliteration point of the artery
- a clear, sharp sound as blood first begins to pass through the compressed area. this is often barely discernable for a 10-mm drop in pressure. this is the systolic pressure
- a murmur of variable duration replacing the above, during the next 15-mm fall
- a clear, loud and snappy sound replacing the murmur, for the next 15-mm fall
- a transformation of the clear lound sound into a dull one lasting throughout the next 5- to 6-mm fall
- the disappearance of all sound (diastolic pressure)
blood pressure cuff
sphygmomanometer
normal heart rate
60-80 beats/min
heart murmurs
- generated by turbulent flow of blood, which may occur inside or outside the heart
- may be physiological (benign) or pathological (abnormal)
two causes of abnormal murmurs
- stenosis restricting the opening of a heart valve
- may occur with valvular insufficiency (or regurgitation), which allows backflow of blood when the incompetent valve closes with only partial effectiveness
S3
- protodiastolic gallop
- ventricular gallop
- “kentucky” gallop
- thought to be cause by the oscillation of blood back and forth between the walls of the ventricles initiated by inrushing blood from the atria
- may also be a result of tensing of the chordae tendineae
right-sided vs. left-sided S3
- right-sided S3 will increase on inspiration
- left-sided S3 will increase on expiration
S4
- presystolic gallop
- artrial gallop
- produced by the sound of blood being forced into a stiff/hypertrophic ventricle
- usually a sign of a failing left ventricle or restrictive cardiomyopathy
- occurs just after atrial contraction (“atrial kick”) at the end of diastole and immediately before S1
- “Tennessee” gallop
quadruple gallop
- combined presence of S3 and S4
- “Hello-Goodbye” gallop
summation gallop
- S7
- at rapid heart rates, S3 and S4 merge
