BIO2340- Exam 3

Match each label (A, B, and C) on the graph of pacemaker potentials with the correct ion channel description. Note: you will not use all the options!

A. Funny channels open, Na moves in, k+ movesout B. T Type calcium channels open, calcium moves in C.L type calcium channels open, Calcium moves in

Which statement best describes explains the loading and unloading of oxygen in hemoglobin? (Hint: law of mass action) As oxygen level rises, so does the pressure, which breaks the bonds of hemoglobin thereby releasing hemoglobin to the tissues. As oxygen levels in the pulmonary capillaries decrease, more carbaminohemoglobin is formed due to the concentration of carbon dioxide. As oxygen levels in the pulmonary capillaries increase, more oxyhemoglobin is formed. Conversely, as oxygen levels in the systemic capillaries decrease, the reaction reverses and releases oxygen from hemoglobin. Oxygen has a greater mass than carbon dioxide and therefore can load more quickly than carbon dioxide.

As oxygen levels in the pulmonary capillaries increase, more oxyhemoglobin is formed. Conversely, as oxygen levels in the systemic capillaries decrease, the reaction reverses and releases oxygen from hemoglobin.

Which is NOT true about the Carbonic Acid equation? In the blood, this reaction can decrease the blood pH An increase in CO2 causes a decrease in H+ Carbonic Anhydrase is the enzyme that speeds up the equation The end products of Carbonic Acid disassociation are hydrogen and bicarbonate

An increase in CO2 causes a decrease in H+

Which of the following describes the effect of end-diastolic volume on stroke volume? An increase in end-diastolic volume stretches ventricular muscle cells to lengths closer to optimum, increasing the strength of contraction and thereby increasing stroke volume. A decrease in end-diastolic volume creates a vacuum drawing more blood into the ventricle increasing stroke volume. A decrease in end-diastolic volume allows cardiac muscle to relax, conserving energy for the next contraction, thereby increasing stroke volume of that next contraction. An increase in end-diastolic volume stretches ventricular muscle cells to lengths greater than optimum, decreasing the strength of contraction and thereby decreasing stroke volume

An increase in end-diastolic volume stretches ventricular muscle cells to lengths closer to optimum, increasing the strength of contraction and thereby increasing stroke volume.

Place the events of the conduction system of the heart in the correct order. 1 2 3 4 5 6

1. AP initiated in SA node 2. Signal spreads through atria 3.AP signal spreads through the atria to the AV node, where conduction slows 4.Signal travels through bundle of his 5.Signal splits into R and L bundle branches 6.Ap spread upward through the purkinje fibers into the ventricular muscle

Place the events of inspiration in order. 1 2 3 4 5

1. Neural stimulation of inspiratory muscles 2. Diaphragm contraction and external intercostal muscles contract increasing lung volume 3. Outward pull on pleura decreases intrapleural pressure, which results in an increase in transpulmonary pressure 4. Alveoli expand, decreasing alveoli pressure. 5. Air flows into alveoli by bulk flow

What does contraction of the diaphragm cause?

Contraction of the diaphragm causes the volume of the lungs to increase. The external intercostal muscles as well contract increasing the volume of the lungs. This allows air to move into the lungs because air travels from high pressure to low pressure.

Match each letter with the correct description of the events occuring during ventilation. Please note, the descriptions do not describe what the figure is showing you. You need to be able to identify what is occuring the the lungs/thoracic cavity according to the pressure and volume readings in the figure!

Correct!A at rest, functional residual capacity. Correct!B increased thracic volume, inspiration Correct!C intra-alveolar pressure equal to atmospheric pressure between inspiration & expiration Correct!D inspiratory muscles relax, pressure increases in the alveoli, expiration

ATP is required to remove calcium from the cytosol of muscle cells and end a muscle contraction. T F

False

During isometric contraction. the muscle fiber shortens. T F

False

Which statement best describes why atrial depolarization is usually not detected on a normal ECG? It occurs at the same time as the QRS complex. The electrodes cannot be placed high enough on the chest to detect the atria. The atria are so small and the depolarization happens so quickly that it cannot be detected. The voltage change in the atria is minimal and therefore does not register on an ECG.

It occurs at the same time as the QRS complex.

List the six steps of excitation-contraction coupling in skeletal muscle. (make a list, be concise!) 1 2 3 4 5 6

List the six steps of excitation-contraction coupling in skeletal muscle. (make a list, be concise!) Your Answer: 1. Action potential reaches the sarcolemma. 2. Action potential travels down the T Tubules. 3. DHP receptors of T Tubules open Ca Channels. 4. Ca increases in cytosol. 5. Ca binds to troponin, shifting tropomyosin. 6. Crossbridge cycling occurs.

Which of the following is a property of isotonic skeletal muscle contraction? Load is greater than the force generated by the muscle Load is less than the force generated by the muscle. There is a rapid increase in force with no change in muscle length Muscle length will be increased by contraction.

Load is less than the force generated by the muscle.

In excitation-contraction coupling, calcium plays an important role in contraction. If no calcium is present, what happens? (Select all that apply) (Hint: what happens when calcium is not released from SR?) No crossbridges form between actin and myosin motor neuron releases ACh troponin holds tropomyosin over myosin binding sites on actin Muscle is relaxed acetylcholinesterase breaks down ACh

No crossbridges form between actin and myosin troponin holds tropomyosin over myosin binding sites on actin Muscle is relaxed

Which is NOT true about the P O2 in the lungs? O2 is very soluble in water or plasma The P O2 is greater in the lungs than in the capillaries surrounding the alveoli so O2 moves into the capillaries The P O2 in the lungs is lower than in the atm The PO2 is about 100mmHg

O2 is very soluble in water or plasma

Which of the following components of an ECG represents atrial depolarization? PQ interval P wave QRS complex T wave

P wave

What is the primary driving force for the binding of oxygen to hemoglobin? PCO2 pH PO2 temperature

PO2

The functional (contractile) unit of muscle is called a ___________. (one word)

Sarcomere

Which of the following is an effect of parasympathetic activity to the heart? cAMP is activated. Heart rate is increased The rate of spontaneous depolarization in SA nodal cells decreases. SA nodal cells are depolarized.

The rate of spontaneous depolarization in SA nodal cells decreases.

When intra-alveolar pressure is greater than atmospheric pressure, air moves out of the lungs. T F

True

Equilibration of pressure between the intrapleural space and the alveoli will lead to which of the following? chronic obstructive pulmonary disease air moving into the lungs air moving out of the lungs a pneumothorax (the lung will collapse)

a pneumothorax (the lung will collapse)

An increase in vagus nerve activity results in a decreased heart rate as a result of activating muscarinic ACh receptors increase open state of K+ channels decreased rate of pacemaker depolarization increased closed state of Ca2+ channels

activating muscarinic ACh receptors increase open state of K+ channels decreased rate of pacemaker depolarization increased closed state of Ca2+ channels

The figure below shows the relationship between frequency of stimulation and force generated by a muscle fiber. The reason(s) why the tension increases with each stimulus is at high frequency, calcium release is faster than reuptake calcium levels in the cytosol are increasing all of the options are correct more calcium allows for more crossbridge formation

all the options are correct

Why does the amount of tension produced eventually plateau? (the blue dotted line) ACh release is depleted sodium channels become blocked the hypothalamus is fatigued all troponin has calcium bound to it

all troponin has calcium bound to it

Which of the following is responsible for the repolarization of pacemaker cells? an increase in PNa a decrease in PK an increase in PCa an increase in PK

an increase in PK

Which muscles are innervated by autonomic nervous system? cardiac muscle smooth muscle skeletal muscle

cardiac smooth

Hypoventilation would lead to a(n) ________ within the systemic arteries. selective decrease in PCO2 increase in PO2 and decrease in PCO2 decrease in PO2 and increase in PCO2 selective increase in PO2

decrease in PO2 and increase in PCO2

Which of the following will cause a shift in the hemoglobin-oxygen dissociation curve to the right? decrease in pH increase in temperature increase in 2,3-BPG (2,3-bisphosphoglycerate) increase in pH

decrease in pH increase in temperature increase in 2,3-BPG (2,3-bisphosphoglycerate)

What happens to the inner diameter of the walls of the respiratory tract as it moves down from the upper conducting zone to the lower respiratory zone? increases decreases no change thickens

decreases

As the lungs expand, intra-alveolar pressure ________ and air moves ________ the lungs. increases : out of does not change : neither into nor out of decreases : into increases : into

decreases : into

The opening and closure of the atrioventricular and semilunar valves is driven by contraction of the valve contraction of muscles attached to the valves contraction of the ventricle and atria that pull the valves into place. differences in pressure across the valve.

differences in pressure across the valve.

What is the volume of air present in the lungs when the lungs are at rest (in between breaths)? tidal volume zero functional residual capacity total lung capacity

functional residual capacity

Which type of skeletal muscle fiber fatigues rapidly? oxidative glycolytic isotonic fast

glycolytic

Cardiac output is determined by what two variables? preload ejection fraction heart rate stroke volume afterload

heart rate stroke volume

What is an increase in alveolar ventilation to match the demands of increased metabolic activity in the cells called? hyperpnea hyperventilation hypoventilation dyspnea

hyperpnea

Hyperventilation would lead to a(n) ________ within the systemic arteries. selective decrease in PO2 decrease in PO2 and increase in PCO2 selective increase in PO2 increase in PO2 and decrease in PCO2

increase in PO2 and decrease in PCO2

What does contraction of the diaphragm cause? increase in the volume of the thoracic cavity and, therefore, an increase in intra-alveolar pressure decrease in the volume of the thoracic cavity and, therefore, a decrease in intra-alveolar pressure increase in the volume of the thoracic cavity and, therefore, a decrease in intra-alveolar pressure decrease in the volume of the thoracic cavity and, therefore, a decrease in atmospheric pressure

increase in the volume of the thoracic cavity and, therefore, a decrease in intra-alveolar pressure

Which of the following will increase the unloading of oxygen within the tissue? increased hydrogen ion concentration increased body temperature increased PCO2 increased pH

increased hydrogen ion concentration increased body temperature increased PCO2

What phase of the cardiac cycle is the heart in when all four valves of the heart are closed and ventricular pressure is building, but is not yet great enough to open a valve? ventricular filling isovolumetric relaxation ventricular ejection isovolumetric contraction

isovolumetric contraction

The compliance of the lungs can be determined by measuring the change in ________ for a given change in ________. lung volume : transpulmonary pressure airway resistance : lung volume lung volume : intra-alveolar pressure lung volume : airway resistance

lung volume : transpulmonary pressure

Contraction of skeletal muscle fibers is stimulated by what type of neuron? (not a trick!) afferent Motor parasympathetic sensory sympathetic

motor

What molecule, present primarily within oxidative skeletal muscle cells, acts as an oxygen buffer due to its ability to bind oxygen? myoglobin hemoglobin myosin myosin light chain

myoglobin

Which type of skeletal muscle fiber contains a high concentration of mitochondria? glycolytic oxidative slow fast

oxidative

Closure of the atrioventricular valve occurs when the atrium contracts pressure inside the ventricle is greater than pressure inside the atrium pressure inside the ventricle is less than pressure inside the atrium. the papillary muscle contracts

pressure inside the ventricle is greater than pressure inside the atrium

What is the function of ciliated cells in the conducting zone? produce a viscous solution called mucus provide the rigid support that keeps the conducting zone open engulf foreign material that has been trapped within the mucus push mucus containing trapped particles upward toward the glottis

push mucus containing trapped particles upward toward the glottis

The arrow is pointing to the _____________ phase of a typical twitch. During this phase, calcium _________ is occuring. latent; release relaxation; reuptake latent; reuptake relaxation; release

relaxation; reuptake

What is the function of the sodium-calcium exchanger in cardiac muscle? interact with troponin to initiate cross-bridge cycling depolarize the cell remove calcium from the cytosol by transporting it to the extracellular fluid thereby relaxing the muscle trigger the release of calcium from the sarcoplasmic reticulum

remove calcium from the cytosol by transporting it to the extracellular fluid thereby relaxing the muscle

What is the thin barrier (0.2 μm) that allows for the efficient exchange of gases between the lungs and the blood called? respiratory membrane alveolar pores alveolar macrophage endothelial cell

respiratory membrane

The SA node is innervated by the sympathetic nervous system parasympathetic nervous system somatic nervous system

sympathetic nervous system parasympathetic nervous system

During isovolumetric relaxation the AV and semilunar valves are closed and ventricular pressure is decreasing. AV valves are open, the semilunar valves are closed, and ventricular pressure is the AV and semilunar valves are open and ventricular pressure is increasing AV and semilunar valves are closed and ventricular pressure is increasing

the AV and semilunar valves are closed and ventricular pressure is decreasing.

In crossbridge cycling, converts the myosin head into the high-energy state? binding to titin binding to ATP only the hydrolysis of ATP binding to actin

the hydrolysis of ATP

Under resting conditions, heart rate is primarily under the control of what control system? epinephrine the parasympathetic nervous system somatic nervous system the sympathetic nervous system

the parasympathetic nervous system

As skeletal muscle is stretched beyond the length where optimum force is developed, the thin filaments are pulled away from the thick filaments, thereby reducing actin's ability to interact with myosin. the amount of calcium released by the sarcoplasmic reticulum is reduced as length increases the tendons are stretched beyond optimal length the thin filaments overlap one another, thereby reducing their ability to interact with myosin

the thin filaments are pulled away from the thick filaments, thereby reducing actin's ability to interact with myosin.

Which of the following is a measure of the distending (streching outward) force across the lungs? difference between intra-alveolar pressure and atmospheric pressure transpulmonary pressure intrapleural pressure intra-alveolar pressure

transpulmonary pressure

A muscle is stimulated at a frequency that allows the muscle to relax completely between contractions. However, the amount of tension increases with each contraction. What is this called? summation tetanus recruitment treppe

treppe

During increased exercise, the oxygen dissociation curve shifts to the right in response to increased temperature. This causes more ________ and less ________ of oxygen in the tissues where it needs to be delivered. saturation; binding loading; unloading unloading; loading unloading; CO2

unloading; loading

Blood is ejected from the left ventricle once pressure within the ventricle is greater than pressure within the aorta. muscles of the pulmonary semilunar valve relax. ventricle is less than pressure within the aorta ventricle is greater than pressure within the pulmonary artery.

ventricle is greater than pressure within the aorta.