Practical Exam 2 PhysioEx Flashcards
What happens if the frog heart is stimulated during the relaxation phase of the contraction cycle?
and extrasystole (extra ventricular contraction) can be created
What would prevent the heart from pumping blood properly? (2)
tetanus and wave summation
Without what phase, will blood flow from the heart stop? Why?
relaxation; it allows the ventricles to fill with blood
the long refractory period of cardiac muscle prevents…(2)
tetanus and wave summation
stimulation of the vagus nerve does what to the heart rate?
decreases it
how does the vagus nerve conduct signals to the heart?
parasympathetic division of the autonomic nervous system
what would happen if the vagus nerve is severed?
the heart rate would increase because it would no longer be slowed by the parasympathetic division
what can occur if the vagus nerve is stimulated too much?
vagal escape
vagal escape
caused by the sympathetic reflexes or initiation of a rhythm by the Purkinje fibers
why is Ringer solution required to maintain heart contractions?
since it contains ions like chloride, sodium, potassium, calcium, and magnesium needed for the cardiac cells to undergo contractions
what does a decrease in temperature do to heart rate?
decreases it
what does a increase in temperature do to heart rate?
increases it
_____ and _____- an adrenergic chemical modifier, increases heart rate similar to sympathetic stimulation
epinephrine, atropine
both _____ and _____ are cholinergic chemical modifiers that function similar to acetylcholine- reducing heart rate
pilocarpine, digitalis
ions can be _____ and/or _____
chronotropic, inotropic
addition of _____ to the ringer solution caused an increase in heart rate
calcium
calcium is a _____ chronotropic and ______ inotropic agent
positive, positive
what is a way to reduce blood pressure?
using calcium channel blockers that reduce heart contraction force and rate
what are calcium ions important for in cardiac muscle cells? (2)
- plateau of the action potential in myocardiocytes
- also used during active muscle contraction
addition of _____ and _____ to the ringer solution caused the heart rate to decrease and then become erratic, why?
sodium, potassium
- these are involved in the depolarization and repolarization phases
during obstructive diseases such as _____ _____ and ____, the airway radius decreases
chronic bronchitis, asthma
what can you measure to tell if someone has chronic bronchitis or asthma?
forced expiratory volume (FEV)
what is indicative of an obstructive problem and not a restrictive problem?
as airway radius decreases, there was a corresponding decrease in the FEV
people suffering from _____ have lungs that have less elastic recoil
emphysema
what causes the residual volume to increase in those with emphysema?
inspiration becomes easier, (greater compliance), expiration requires more muscular effort, leaving more air inside the lungs
people suffering from _____ experience greater resistance to inspiration and expiration
asthma
what do athma treatments do?
the cause dilation (relaxation of the smooth muscle) of the airways to reduce resistance to airflow
what is used to diagnose if a person is suffering from obstructive or restrictive lung disease?
FEV1/FVC ratio
what is a normal FEV1/FVC ratio?
80%
people suffering from emphysema or acute asthma have _____ respiratory system and have a FEV1/FVC ratio of less than 80%
obstructive
the intrapleural pressure is normally _____ than the air pressure within the alveoli
less
what happens if the intrapleural pressure and alveolar pressure are equal?
the lung collapses
the alveoli are coated in a fluid that does what? (2)
- protect them
- promote gas exchange
at a gas-liquid boundary, molecules in a fluid tend to..
stick together, creating surface tension
what substance is released by septal cells in the alveoli to decrease surface tension there?
surfactant
the more surfactant added, the _____ the reduction of surface tension and the _____ the flow rate
greater, greater
what happens if surfactant is absent?
this is seen in premature infants, the surface tension in the alveoli would be too high to allow them to fill with air
since the pleural cavity exerts _____ pressure than the air pressure inside the alveoli, they remain inflated
less
enzymes
mostly proteins that help catalyze chemical reactions
what can affect enzyme function? (2)
pH and temperature
what could happen if you boil and enzyme?
it might unfold, and upon cooling it might not fold back properly and lose its function, this is seen in tube 1
what happens if you freeze an enzyme?
nothing, it will retain its structure and function upon thawing, as seen in tube 2
what was IKI used for?
to detect the presence of starch
what was Benedict’s reagent used for?
to detect the presence of reducing sugars like glucose of maltose
what shows that amylase works well at pH 7?
in tube 3, all of the starch hydrolyzed into monosaccharide components (glucose) since the IKI test was negative while the Benedict’s test was positive
what happened in tubes 7 and 8?
both the IKI and Benedict’s tests were positive
- they had different pH buffers causing amylase functions to decrease
what was tube 5?
it was a control to ensure that the starch did not spontaneously break down into glucose and required the presence of functional amylase to hydrolyze
what was tube 6?
it was a control to ensure that the Benedict’s test was detecting the presence of reducing sugar, this was maltose
what was tube 4?
it was another control, this tube lacked starch so it was to ensure a positive IKI and Benedict’s test were due to the presence of starch and its reducing sugar and not because of the presence of the amylase of the buffer
cellulose
a polysaccharide that is composed of glucose linked in a different fashion than starch
what result from the IKI test would occur if there is cellulose present?
a positive one
will amylase break down cellulose? why or why not?
no, it’s glucose molecules are linked in a different fashion
