Lab 6Background From Lab Handout

● Human body has 3 types of muscle tissue that aid in homeostasis○ Skeletal, cardiac, smooth

● SkM- attached to skeleton ○ Contraction moves one body part with respect to another○ Contraction of several muscles in coordination moves entire body

● Primary function of muscle - convert chemical energy to mechanical work → muscles contract ● Muscle contraction is dramatic and energized by ATP● SkM and CM are striated → repeating bands and lines perpendicular to the length of the muscle fiber

○ Band is caused by organized, parallel arrangement of myofilaments within myofibrils ● 2 types of myofilaments

○ Thick - myosin (contractile)○ Thin - actin (contractile)

● Actin and myosin filaments arranged so they overlap in orderly, repeated manner which creates sarcomeres○ Filaments bundled in cylinder, the repeating overlap results in banding

■ Different bands of sarcomere given letters to designate

● Contraction occurs through the interaction of actin and myosin filaments in the sarcomere ○ Actin pulled centrally when myosin crossbridges bind to the actin (Sliding Filament Theory)

■ Causes I bands (thin filaments) to become smaller with the A bands (some thin and mainly thick filaments) moving closer together, BUT not changing in size → overall width of sarcomere decreases

● To initiate contraction, myosin heads have to be activated by ATP and signals must be initiated from the somatic nervous system

○ Signal is a nerve impulse to the muscle fiber → intracellular release of Ca ions from the SR ■ Ca initiates contraction by interacting with regulatory proteins associated with actin

● In a normal muscle fiber rich in ATP, myosin heads are activated and ready to contract, but can’t until Ca is released

○ Contraction cycles as long as Ca is high and ATP is available ● Human SkM made of 100’s of individual muscle fibers bound by connective tissue

○ Body: SkM stimulated to contract by somatic motor neurons that carry signals in the form of nerve impulses from the brain or spinal cord to SkM

● Each muscle fiber is innervated by 1 motor neuron (though several muscle fibers can be innervated by a single motor neuron)

● Motor unit - single motor neuron and all the muscle fibers it controls ● When somatic motor neuron is activated, all muscle fibers it innervates respond to impulses by making own

electrical signals → contraction of activated muscle fibers● Impulse of 1 fiber is weak; many fibers conducting simultaneously induce voltage difference in skin that can be

detected by electrodes● Electromyography - detection, amplification, and recording of changes in skin voltage produced by underlying

SkM contraction○ Electromyogram (EMG) - recording obtained

● EMG signal is the recorded outcome of 2 bioelectric activities○ 1. Propagation of motor nerve impulses and their transmission at the NM jxn as a motor unit ○ 2. Propagation of muscle impulses by the sarcolemma and the T-tubule resulting in excitation-

contraction coupling● Glycerination process removes ions and ATP from the tissue, as well as disrupts regulatory proteins so that

binding sites on actin are no longer blocked○ No Ca needed to induce contraction ○ No ATP is present, so myosin heads are NOT activated

■ Allows for investigation of muscle contraction with the addition of ATP and ions (in vitro experiment)

○ Rabbit psoas muscle used

Review Questions:● Describe the process of muscle contraction and how this relates to the sliding filament theory.

○ Contraction occurs through the interaction of actin and myosin filaments in the sarcomeres○ Actin is pulled centrally when mysoin cross bridges bind to actin

■ This causes the I bands (thin filaments) to become smaller with the A bands (thick mainly) to move closer together

● Overall width of sarcomere decreases

● How are actin and myosin involved in contraction; what is the importance of ATP?○ To initiate contraction, myosin heads have to be activated by ATP and signals in the form of a nerve

impulse must be initiated from the somatic nervous system■ Leads to intracellular release of Ca from the SR

● Ca initiates contraction by interacting with regulatory proteins associated with actin

○ In a normal muscle fiber rich in ATP, myosin heads are activated and ready to contract, but can’t until Ca is released

■ Contraction cycles as long as Ca is high and ATP is available

● Define the following terms: sarcomere, motor unit, muscle fatigue.○ Sarcomere - the structural subunit of of a myofibril in a striated muscle; equal to the distance between 2

successive Z lines ○ Motor unit - single motor neuron and all the muscle fibers it controls○ Muscle fatigue - decline in ability of a muscle to generate force (can be result of vigorous exercise)

● Discuss the role Ca plays in contraction.○ Ca is released from the SR and initiates contraction by interacting with regulatory proteins associated

with actin

● What is electromyography?○ detection, amplification, and recording of changes in skin voltage produced by underlying SkM

contraction■ Electromyogram (EMG) - recording obtained

○ EMG signal is the recorded outcome of 2 bioelectric activities■ 1. Propagation of motor nerve impulses and their transmission at the NM jxn as a motor unit ■ 2. Propagation of muscle impulses by the sarcolemma and the T-tubule resulting in excitation-

contraction coupling

● Describe the relationship between muscle length and muscle tension; how does this translate to the human body?

○ Muscles are at a resting length when they are not contracting; stretched to this length○ The natural resting length of our skeletal muscles is the ideal length for maximum contraction → Length-

Tension Relationship

LAB WORKSHEET QUESTIONS● Muscles can only contract in the presence of BOTH salt and ATP. ● More strength was required to lift the hand and the 5 pound weight than just the hand alone. This shows that a

greater electrical current was required to lift a heavier weight than a lighter one. ● HAND POSITIONING: When the hand is extended, the most force is exerted by the muscle to lift the object.

When the hand is flexed upward, the force exerted by the muscle is not as high as when the hand is extended.● Grip strength is greater in the dominant hand vs .the non dominant hand● Males have a higher grip strength than females● Difference in strength between fingers:

○ The index finger had the greatest strength, followed by the middle finger, ring finger, and little finger respectively.

■ The smallest difference was observed between the middle finger and the ring finger which makes sense because these fingers are beside each other and have the similar functions.

■ The largest difference was observed between the index finger and the little finger. This makes sense because the index finger is used the most and the little finger is used the least.

● Greatest force generated at 0 degree position → more natural ● Least force generated at -90 degrees● Ankle weights: The dominant leg took longer to fatigue than the non dominant leg; more weight, fatigue faster.

SUMMARY/APPLICATION QUESTIONS1. A stroke, which is the loss of blood flow to a region of the brain, is a major medical emergency that may lead to paralysis, a loss of muscle function. Imagine that you are a doctor treating a stroke patient who has lost complete muscle function of the left side of his body. Explain what you think is happening physiologically to hinder the patient’s ability to move his muscles. (0.5 pts)

● Loss of blood flow to the brain will cause that particular region of the brain to not function properly. In the case of a stroke that results in loss of muscle function, blood flow to a region of the brain that controls muscle movement would have been lost. This would make that part of the brain impaired, and thus unable to recognize signals sent from a muscle to that part of the brain.

2. How does a muscle “know” how much force is required to perform a specific action? How does muscle meet changing force requirements? (0.5 pts)

● The muscle “knows” how much force is required based on the load the muscle is trying to move. The muscle will exert tension to move the load: if load is greater than tension, the object won’t move; if the load is less than the tension, the object will move. The muscle also knows based on the strength and frequency of the action potential the muscle receives. The muscle meets changing force requirements by stimulating certain amount of motor units to contract - more units are stimulated when greater force is needed.

3. When measuring pinch strengths, what caused the different pinch strengths? List at least two possible reasons for the differences you see in pinch strength between different fingers. (Hint: Think about the anatomy of the hand and consider the actions of the hand muscles). (1pt)

● The difference in pinch strength was caused by the difference in function between the different fingers. One possible reason for this is the different function of the fingers. It makes sense that the index finger has the greatest strength because the index finger is used a lot more. The middle and ring fingers had similar strengths because they have similar functions since they both are in the middle of the hand. The pinky finger had the least strength because it is used the least.

● Another reason for the differences in pinch strength relates to the anatomy of the hand. Muscles are more concentrated around your thumb and index finger, which would explain why the index finger has a greater strength. Muscles are less concentrated in the middle region of the hand which explains the decrease in strength in the middle and ring fingers. The muscles surrounding the area of the pinky finger are stretched thinner, so it is harder to create more force with that finger.

4. Based on the results you obtained, what conclusions can you draw about how much force a muscle generates related to the length that the muscle is extended? (0.5 pts)

● The more that the muscle is extended or flexed, the more force that is required to lift/move the load. The neutral position (the resting part) had the lowest amount of force generated.

LAB 7Blood

● Blood - fluid connective tissue● Functions of Blood

○ Carrying soluble molecules (oxygen and nutrients) ○ Removing wastes○ Hormonal and temperature regulation○ Protection via clotting and defense mechanisms

● Formed elements-- cellular portion of blood ○ Erythrocytes (RBCs) -- present in the greatest number○ Leukocytes (WBCs)○ platelets / thrombocytes

● Hematocrit (HCT) - proportion, by volume of blood that consists of RBCs○ Expressed as a percentage

○ Ex HCT of 25 = 25% of blood volume is RBCs○ Higher HCT the more RBCs available to transport oxygen

● MAIN FUNCTION OF RBCs = transport oxygen from lungs to cells throughout body● Polycythemia = higher than normal HCT

○ People living in high altitudes○ Chronic smokers○ Dehydration can falsely produce high HCT but returns to normal when fluids are back in balance

● anemic= lower than normal HCT● antigens= genetically determined molecules on all cells; identify cells as “self” in the human body

○ The difference in blood types ● Antibodies = present in plasma, directed against antigens for other blood types● Agglutination = blood clumping; mixing incompatible blood types lead to this.● MAIN FUNCTION OF WBCs (Leukocytes)= immunity

○ Granulocytes■ Neutrophils■ Eosinophils■ basophils

○ Agranulocytes■ Lymphocytes■ Monocytes

The Heart● Four chambers divided into right and left side- atrium and ventricle ● Atria - reservoir for venous blood

○ Minimal pumping action○ Assist ventricular filling

● Ventricles - major pumping chambers ○ Deliver blood to the pulmonary and systemic circulations○ R ventricle feeds the pulmonary ○ L ventricle feeds the systemic

■ Conical in shape■ Needs to generate more pressure than R ■ Has a thicker and more muscular wall

● Valves are present to ensure one way flow; prevent backflow ○ Atrioventricular - between atria and ventricle○ Semilunar - leaving ventricle out into circulation

● Myocardium ○ Pacemaker cells - cardiac muscle cells that contract spontaneously○ Conducting cells - conduction of electrical signal throughout heart

● Myocardial contraction results from change in voltage across cell’s plasma membrane (depolarization) leading to action potential

● Sinoatrial (SA) node - origin of an electrical impulse to initiate contraction○ Collection of pacemaker cells which depolarize spontaneously ○ Located at the junction of right atrium and superior vena cava

● Atrioventricular (AV) node - impulse moves from SA node to this node, located in the septal wall of right atrium

● Purkinje fibers - allow for rapid conduction of electrical impulse causing almost simultaneous depolarization of BOTH ventricles

● Conduction System of the Heart: (picture above)SA node → AV node → interventricular septum via atrioventricular bundle → purkinje fibers → out of ventricle

● ECG = electrocardiogram; recording of the heart’s electrical activity via electrode placed on skin ○ Does NOT record action potentials○ Records the result of production and conduction of action potentials in heart ○ Helpful in diagnosis of conditions ○ Reflects electrical activity

NEED TO KNOW

Components of ECG● Electrical events of heart recorded as a pattern from baseline/isoelectric line

○ P wave→ QRS wave→ T wave● P wave -- represents depolarization of the right and left atria● QRS complex wave -- represents depolarization of right and left ventricles and atrial repolarization

○ Largest recorded waveform○ Reflects the depolarization of left ventricle more due to greater mass ○ Orientated MEA to the left of interventricular septum

● T wave --represents repolarization of right and left ventricles● Cardiac Cycle -- sequence of cardiac excitation results in mechanical events of the heart

○ Heart depolarize along cardiac cycle route in a specific sequence○ Electrical activity has directionality (spatial orientation represented by electrical axis)

● Mean electrical axis (MEA) -- preponderant direction of electrical activity during cardiac cycle ○ Typically lies along line from base to apex of heart ○ Summation of all vectors occurring during cardiac cycle

● Magnitude recorded voltage is DIRECTLY proportional to amount of tissue being depolarization ● ECG lead - record of electrical activity generated by heart, detected by electrodes placed on skin

○ Bipolar lead - two electrodes of opposite polarity ○ Lead axis - hypothetical line joining poles of a lead

● Electrode placement defines recording direction of lead-- negative to positive electrode.● The recorders computes the difference between positive and negative electrodes and

displays the change in voltage ● Einthoven’s Law - the sume of electrical activities in lead I and III equal the sum of

electrical activity recorded of lead II.● Measurement of lead = vector; velocity

○ Length of shaft = magnitude of current○ Orientation of arrow = direction ○ Tip of arrow = positive pole○ Tail of arrow = negative pole

● Einthoven’s Triangle - the leads’ formation form a triangle with the heart at center ○ Forms an equilateral triangle ○ Creates a standard limb vectorgraph with each lead xis form 60-degree angle- used to plot vector

representing MEA

QRS represents majority of electrical activity - use this to approximate MEA● Plot lead I and Lead III → draw perpendicular line from ends of vectors → find point of intersection→ draw new

vector from 0 to the point of intersection-- ○ Direction approximates MEA

■ Somewhere between -30 to +90 degrees ○ Length approximates mean potential

● MEA factors○ When changing body position (sitting to standing)○ Individual differences such as heart mass, orientation of heart, BMI

● LAD - left shift axis deviation; abnormal; results in conditions that cause left ventricle to take longer than normal to depolarize- hypertrophy, systemic hypertension (between -30 and -90 degrees)

○ Can occur when left ventricualr myocardium is damaged- creating blockage and slowing down signal ○ Can be caused by drug injuries, coronary occlusion

● RAD - right shift axis deviation; may be normal in youinug adults but can be associated with hypertrophy of right ventricle or damage to R ventricle

○ Results from a slowing or blockage of depolarization signal for R ventricle

Laboratory Review Questions:Define what are the formed elements, their function and normal values in the human body.

● Formed elements → RBCs & WBCs, platelets ● Erythrocytes - RBCs

○ More numerous ○ flattened , concave discs, lack nuclei and mitochondria; Contain hemoglobin molecules ○ FUNCTION: transport oxygen○ Cubic millimeter of blood - 4.3 million to 5.8 million RBCs

■ Men have greater volume● Leukocytes → WBCs

○ Granular-- granules in cytoplasm ■ Eosinophiles■ Basophiles■ Neutrophiles- most abundant

○ Agranular -- lack granules in cytoplasm■ Lymphocytes - second most numerous■ Monocytes - largest of leukocytes

○ Contain nuclei and mitochondria, amoeboid movement○ FUNCTION: immune response○ Cubic millimeter of blood - 5,000-9,000 WBCs

● Platletes/thrombocytes ○ Smallet of formed elements ○ Fragments of megakaryocytes from bone marrow○ FUNCTION: blood clotting○ Cubic milllimeter of blood - 130,000- 400,000

What does a HCT represent? Is it the same for men and women?● HCT = hematocrit● Represents the percentage of RBC volume to total blood volume ● Women: 36%-46%● Men: 41%-53%● Normal homestatic range- 4.2-6.2 million per mm3

Discuss what is involved in determining an individual’s blood type.

● Blood type determined by presence or absences of certain antigens on RBCs● Type A - A antigens; antiB antibodies in plasma● Type B - B antigens; antiA antibodies in plasma● Type AB - A and B antigens; NO ANTIBODIESS- universal reciepent● Type O - No antigens; antiA and antiB antibodies in plasma-universal donor● Rh factor - another type of antigen present on RBC

○ RH+ is most common ● DETERMINING A BLOOD TYPE:

○ Prick finger and place a drop of blood in 3 wells○ Add a drop af antiA serum in one well, AntiB in another and antiRH in another○ Mix with a toothpick○ Look for aggultination! If there is some then negative○ No aggultination signfies your blood type. ○ But if there is aggultination in antiRh well - means Rh+

What is the function of a blood clot?● Temporary plug a damaged blood vessel ● Promote hemostasis

Describe the difference between contractile cardiac muscle cells, pacemaker cells and conducting cells.● Contractile cardiac muscle cells - contract and relax during a heart beat; found in atria and ventricle● Pacemaker cells - cardiac muscle cells that contract spontaneously; found around SA node they initate electrical

impulse thus initating contracting that then move to conducting cells● Conducting cells - conduction of electrical signal throughout heart; found between SA and AV node

Define the cardiac cycle.● Cardiac cycle - repeating pattern of contraction and relaxation of the heart● Systole - contraction● Diastole - relaxation ● When both atria and ventricles relaxed, blood fils atria ● Build up of pressure results in the AV valves to open and blood flows from atria to ventricles● Left and right atria contract almost simultaneously followed by contraction of R and L ventricle ● Contraction of ventricles expels blood into circulation

List and discuss the components of the conduction system of the heart.● SA node → Av node → atrioventricualr bundle → purkinje fibers● SA node- origin of the action potential

○ AP leave SA node and spread to myocardial cells of R and L atria through gap junctions ○ AP flows down conducting cells reach AV node

● AV node - atrioventricular node; located on the inferior portion of interatrial septum● Atrioventricular bundle - descending along the interventricular septum between L and R side of heart; divides

into R and L bundles ● Purkinje fibers - within ventricular walls; AP spreads from the inner and outer side of heart

○ Causes both ventricles to contract simultaneously and eject blood into pulmonary and systemic circulations

Describe the components of an ECG.● P wave - spread of atrial depolarizations● QRS wave - spread of depolarization into the ventricles● T wave - repolarization of ventricles

What is meant by the mean electrical axis of the heart.

● Mean electrical axis (MEA) -- preponderant direction of electrical activity during cardiac cycle ○ Typically lies along line from base to apex of heart ○ Summation of all vectors occurring during cardiac cycle

● MEA factors○ When changing body position (sitting to standing)○ Indvidual differences such as heart mass, orientation of heart, BMI

Discuss Einthoven’s Law and its relationship to vectorcardiography.● Einthoven’s Law - the sum of electrical activities in lead I and III equal the sum of electrical activity recorded of

lead II.● Measurement of lead = vector; velocity

○ Length of shaft = magnitude of current○ Orientation of arrow = direction ○ Tip of arrow = positive pole○ Tail of arrow = negative pole

● Einthoven’s Triangle - the leads’ formation form a triangle with the heart at center

Can you construct a vectorgraph from collected ECG data and interpret the result.***● Plot lead I and Lead III → draw perpendicular line from ends of vectors → find point of intersection→ draw new

vector from 0 to the point of intersection-- ○ Direction approximates MEA

■ Somewhere betwen -30 to +90 degrees ○ Length approximates mean potential

● SEE PICTURES ABOVE● General Directions for constructing a vector graph to determine MEA:

○ Begin by plotting the R wave value for Lead I along the horizontal, 0° Lead I line on the vector graph as an arrow, beginning with the (0, 0) coordinate. (NOTE: each tick mark is 0.1 mV).

○ Now plot the R wave value for Lead III along the 120° Lead III line as an arrow.○ Draw a perpendicular line extending from the tip of each arrow. Where the two perpendicular lines

cross, Draw an arrow from the (0, 0) coordinate to the intersection of the lines; this is the MEA. The length of the vector is the mean ventricular potential and the angle is the mean ventricular axis.

ADDITIONAL READINGComposition of Blood, Ch 13, pp 406-409Red Blood Cell Antigens & Blood Typing, Ch 13, pp 412-414Blood Clotting, Ch13, pp 414-418Cardiac Cycle, Ch 13, pp 422-424Electrical Activity of the Heart & the Electrocardiogram, Ch 13, pp 425-430

LAB WORKSHEET QUESTIONS

Calcium carbonate is a clotting cofactor and we expected to observe faster clotting and more clotting in that blood sample. However, saline-citrate prevents blood clotting and we expected to observe no blood clotting in that blood sample.

Einthoven’s Law: the sum of the electrical activities, in an electrocardiogram, in lead 1 and 3 equal the sum of the electrical activity of lead 2

Einthoven’s Triangle: the inverted triangle that is formed by the limbs used during an electrocardiography (2 shoulders and pelvis) with the heart at the center; when all voltages are added up, they equal zero potential

What factors might affect the amplitude of the R wave recorded in different the leads? (0.25 pts)● limbs may not have been in the exact same positions which could alter Einthoven’s triangle

○ positioning in general could alter the lead position and thus the amplitude

SUMMARY/APPLICATION QUESTIONS:

1. From a physiological perspective, what does a HCT tell you? (0.5 pts)It can tell you how much oxygen is in the blood and from that if the lungs are functioning properly. It can also tell you how a person lives; for example, polycythemia is a condition associated with higher than normal HCT and is typically seen in people living at high altitudes and smokers. It can also tell you if an individual is dehydrated by a false, high HCT.

2. Clinically, what is the relevance of performing a white blood cell count? (0.5 pts)A white blood count allows the medical professional to evaluate whether an individual is sick or not and with what depending on what types/amount of certain white blood cells are present.

3. Is it important to know or to be able to estimate an individual’s blood clotting time? Briefly explain. (0.5 pts)Yes. It would allow a medical professional to evaluate how much blood a person could lose given how slow it took the clot to form and thus how much blood the patient would need transfused. It could also help the medical professional evaluate what type of wound the patient has; for example, a deeper, larger wound would take longer to clot than a smaller, more superficial one.

4. Type AB is known as universal recipient blood type. Explain briefly why a person with type AB is referred to as the universal recipient. (Hint: look at its antigen-antibody interaction upon blood transfusion.) (0.5 pts)

A person with AB blood type has both A and B antigens on their red blood cells, because they have both, their bodies don’t have any antibodies against other blood types. This allows them to receive any blood type. Also, since Type O has no antigens on the red blood cells, the body can’t make antibodies against it and thus a person with AB can receive Type O blood as well.

5. Does a person with type O blood have A or B antigens on the red blood cells? What can you say about blood type O regarding antigen-antibody interaction upon blood transfusion? (0.75 pts)

No, Type O does not have A or B antigens. This allows Type O to be transfused without risk of agglutination. Since Type O has no antigens on it, the body has no antibodies against it and thus won’t attack it when it is introduced into the body.

Lab 9REVIEW QUESTIONS:

● Explain the process of ventilation and describe why it is a mechanical process.○ Process:

■ Inspiration● Diaphragm contracts - it lowers and flattens (inc thoracic volume)● Intercostal muscles contract and raise the ribs (increase thoracic volume)● Increase in thoracic volume decreases intrapulmonary (intra-alveolar) pressure● Air flows into the lungs

■ Expiration● Respiratory muscle relax - recoil● Decreases lung volume● Raises pressure in within alveoli above atmospheric pressure● Air pushed out

○ Mechanical process because it requires contraction/relaxation of the diaphragm and involvement of intercostal muscles in the chest to change the volume of the lungs and thus change the pressure inside of the lungs which will cause air to move in passively due to the pressure difference

● What is the physiological importance of ventilation?

○ Ventilation creates the opportunity for gas exchange b/t alveolar air and the pulmonary capillary■ Removes CO2 from the blood and provides O2 to the blood (to then be taken to the tissues for

other physiological processes to occur)● Define the various lung volumes and capacities.

○ Volumes:■ Tidal volume (TV)

● Amount of air inhaled or exhaled during each normal (unforced) ventilation■ Inspiratory reserve volume (IRV)

● Maximum volume of air that can be forcefully inhaled after a normal (tidal) inhalation■ Expiratory reserve volume (ERV)

● Maximum volume of air that can be forcefully exhaled after a normal (tidal) exhalation■ Residual volume (RV)

● Volume of air remaining in the lungs after a maximum (forced) exhalation○ Capacities:

■ Vital capacity (VC) ● Maximum volume of air that can be exhaled after a maximum inhalation● used to assess strength of thoracic muscles as well as pulmonary function● = TV + IRV + ERV

■ Inspiratory capacity (IC) ● Maximum volume of air that can be inhaled after a normal tidal expiration ● = TV + IRV

■ Functional residual capacity (FRC) ● Volume of air remaining in the lungs after a normal (unforced) tidal expiration● = ERV + RV

■ Total lung capacity (TLC) ● Total volume of air in the lungs after a maximum (forced) inhalation● = IRV + TV + ERV + RV

● Could you label the parts of a spirogram?

●

● Discuss the differences between restrictive and obstructive pulmonary disorders.○ Restrictive:

■ Vital capacity is reduced to below normal■ Ex: pulmonary fibrosis

○ Obstructive: ■ Vital capacity is normal (b/c lung tissue isn’t damaged)■ Ex: asthma

EXPERIMENTATION:● Describe the difference between lung volumes in males and females. Briefly explain, what might account for

this?Difference in stature would impact the size of the thoracic cavity which would impact lung volume - the smaller

the thoracic cavity, the lower the lung volume. Women tend to have a lower lung capacity than males because most times, women have smaller statures. Males tend to be taller, larger, and bigger in stature than females, and thus have a higher lung volume and capacity. After age 20, lung volume in males and females tend to decrease.

● total minute volume, at rest = TV x breaths/minute - the amount of volume that is inhaled or exhaled during each breath for one minute

● Describe the changes in respiratory rates, tidal volumes and total minute volumes that occurred after each of the following physiologic challenges in terms of CO2 levels and their effect on respiratory drive: (1.5 pts)

a. breath holding Respiratory rate decreased after breath holding. Tidal volume increased after breath holding. Total minute

volume decreased after breath holding. Based on the fact that respiration decreases, CO2 levels must have been low after breath holding.

Respiration should have increased after breath holding because without breathing, CO2 would accumulate in the lungs and thus, with a higher concentration of CO2, respiration would need to increase to eliminate the accumulated CO2.

b. rapid breathing Respiratory rate decreased after rapid breathing. Tidal volume increased after rapid breathing. Total minute

volume increased after rapid breathing. Based on the fact that respiration decreased, CO2 levels must have been low after breath holding. Based on the decrease in respiration rate, CO2 levels must have been low due to the

rapid breathing. This makes sense because the more frequently the gases are exchanged in the lungs, the lower the CO2 concentration in the lungs.

c. exercise Respiratory rate decreased after exercise. Tidal volume decreased after exercise.Total minute volume decreased

after exercise. With the decreased respiration rate, CO2 levels must have been low. However, with exercise, your body requires more oxygen so to increase oxygen, you would need to increase your respiration rate and an increased respiration rate would correspond to an increase in CO2 levels.

SUMMARY/APPLICATION QUESTIONS:● Consider this scenario, if you were taking shallow breaths (TV = 0.2 L) to avoid severe pain from a rib fracture,

what respiratory rate will be required to achieve the same total minute volume you calculated in an average person at rest? Are you surprised by this determination? Briefly explain. (2 pts)

total minute volume calculated in average person at rest = 10 L/minute total minute volume = TV x breaths/minute 20 L/minute = 0.2 L x breaths/minute20 L/minute = 100 breaths/minute 0.2 L

This value is a little surprising because 100 breaths a minute sounds like a very large number of breaths to take a minute when the normal amount of breaths per minute is 20. The value makes sense when you think about it though because if tidal volume is decreased, then breaths per minute would have to increase in order to achieve the same total minute volume.

● In severe emphysema, what one observes is a destruction of lung tissue and reduced recoil. Briefly discuss what you would expect to happen to the TLC and TV. (1 pt)Because the lungs are no longer able to expand to their full volume, the TV decreases but TLC increases.

Emphysema destroys lung tissue, therefore destroying some alveoli where gas exchange occurs. Alveoli left in the lungs are then pressed to take in more air and become larger as a consequence. Because bronchioles collapse, lungs are filled over capacity over time, therefore increasing total lung capacity (TLC).Because of this, reserve volume (RV) increases, and tidal volume (TV) decreases.

● What would happen to your ERV when you are treading water in a lake? Explain your reasoning. (1 pt)ERV would decrease because your tidal volume increases due to participating in exercise. When you exercise,

your need for oxygen would increase.

● How might breathing into a paper bag help someone who is extremely anxious and hyperventilating? (0.75 pts)The bag will collect the CO2 being expelled which will then be inhaled and increase the partial pressure of CO2 in

the blood and bring it back into homeostatic range and lowering ventilation rate.

NOTES:● spirometry: technique for measuring lung volumes and capacities● Pulmonary capacity : the sum of two or more primary lung volumes● Spirogram: idealized tracing of the various respiratory volumes and their relationship to each other

LAB 10Background Information:

● Nephron = functional unit of kidney● Nephrons filter blood to form filtrate and ultimately urine → urine flows out of kidneys → ureters → bladder

(stored here) → excreted from body via ureter● Urinary system

○ Consists of: 2 kidneys, 2 ureters, urinary bladder, urethra○ Maintains blood volume, blood pressure, removes nitrogenous wastes (urea, creatinine), and regulates

electrolyte, acid-base, and water balance Review Questions:

● Understand the general anatomy of the nephron, renal corpuscle and filtration membrane.○ NEPHRON:

■ Functional unit of the kidney■ Consists of the renal corpuscle and renal tubule■ Renal corpuscle is made up of the glomerulus and Bowman’s/glomerular capsule

○ RENAL CORPUSCLE:

● Consists of the glomerulus and Bowman’s/glomerular capsule● Inner visceral layer of glomerular capsule covers the glomerulus - composed of

podocytes with foot-like projections called pedicles that interdigitate to form filtration slits

● Outer parietal layer is separated from the inner by the capsular space● Glomerulus is a collection of fenestrated capillaries

○ FILTRATION MEMBRANE:

■● Made up of the glomerulus (the fenestrated capillaries) and the visceral layer of the

glomerular capsule (filtration slits created by podocytes)● What three processes are involved with urine formation?

○ 1) glomerular filtration■ Renal corpuscle functions as a mechanical filter

○ 2) tubular reabsorption■ Occurs in proximal convoluted tubule (PCT) - cells contain microvilli■ Renal tubule reabsorbs useful solutes from glomerular filtrate back into blood (99% of the

glomerular filtrate is reabsorbed)● Includes ions, urea, water, and nutrients (glucose, amino acids)

○ 3) tubular secretion■ Unwanted substances are transported from the blood and into the renal tubule■ Removes waste products (urea, uric acid, creatinine, drugs like penicillin, aspirin, morphine,

excess ions like H, K, HCO3)■ Occurs primarily in distal convoluted tubule

● What is the driving force for glomerular filtration? What substances are filtered?○ Blood pressure = driving force○ Water, nutrients, waste products, and ions are filtered○ Leukocytes (WBC), erythrocytes (RBC), and plasma protein (i.e. platelets) are NOT filtered

● What is tubular reabsorption? What is tubular secretion?○ Reabsorption

■ When ions, urea, water, nutrients are taken back up into the blood from the tubule○ Secretion

■ When waste products and other unwanted substances are transported from the blood and into the renal tubule

● These things are then secreted from the body in urine

● Describe a countercurrent mechanism.○ Establishes and maintains the osmotic gradient in the interstitial fluid in the medullary region of the

kidneys which allows the kidneys to conserve water by producing concentrated urine○ Has 2 mechanisms

■ 1) countercurrent multiplier■ 2) countercurrent exchanger

● What is the countercurrent multiplier; countercurrent exchanger? What role do they play in the formation of urine?

○ Countercurrent multiplier = nephron loop■ Establishes the osmotic gradient

○ Countercurrent exchanger = vasa recta■ Maintains osmotic gradient set up by the nephron loop