57535019 circulatory physiology

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Circulatory Physiologyby Theresa Knapp Holtzclaw

Introduction

The animal circulatory system transports oxygen and other nutrients to all cells andcarries carbon dioxide and other waste products away. Various factors can affectthe rate of circulation.

In this laboratory, you will:

1. Learn to take pulse and blood pressure in a human subject and gather data for a fitness index

2. Measure the effect of temperature on the heart rate of a small invertebrate,Daphnia magna

Key Concepts I: Blood Pressure and Pulse

Blood moving through the blood vessels exerts pressure againstthe vessel walls. hisblood pressureis highest in the aorta.!tdecreases as the blood moves through the arterioles, capillaries,venules, and veins.


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"ith each contraction of the heart, #ou can feel the expansion andrecoil of the elastic arterieswhere the# pass near the surface of theskin. his is thepulse. "hen #ou take #our pulse, #ou measureheart rate $ the number of times the heart contracts per minute.

!er the next se!eral pages you will learn how to measure blood pressure andpulse and consider how they are affected by !arious conditions.

Blood Pressure

"s you ha!e seen, blood pressure is a measure of the pressure of the blood againstthe walls of a blood !essel. #linically, blood pressure is usually measured in the

brachial $arm% artery, so our discussion will focus on this specific location.

There are two components to blood pressure:

% stolic pressure' he pressure in the arter# during the ventricularcontraction phase of the heart c#cle. he pressure in the vessel ishighest at this time.

% (iastolic pressure' he pressure in the arter# when the ventriclesare relaxed. he pressure is at its lowest point, though it does notdrop all the wa# to )ero.

&ext we will learn how blood pressure is measured.

Understanding Blood Pressure


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'hen we measure blood pressure, we are actually measuring the systolic pressureand the diastolic pressure separately. This is why you always see blood pressure

reported as two numbers, one (o!er( the other. )or example:

!n a blood pressure reading of 11*+*,

11* - s#stolic pressure* - diastolic pressure

The numbers refer to the number of millimeters the pressure will raise a column of

mercury. The blood pressure of teenagers is fre*uently in the range of +-/-.

Measuring Blood Pressure

Procedure for Measuring Blood Pressure1. ou begin b# inflating the cuff. /nce the pressure in the cuff is above the subject0s s#stolic

pressure 1* in this example3, blood cannot flow below the cuff. ou will hear no sound inthe brachial arter# when #ou listen with the stethoscope.


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2. 4s #ou release the pressure valve and slowl# deflate the cuff,blood begins to flow through the arter#.

5. "hen the pressure in the cuff is between the s#stolic anddiastolic pressure, #ou can hear a tapping sound with each pulse.he first tapping sound #ou hear indicates that blood has entered

the arter#. 6ecord this reading as the s#stolic pressure. oucontinue to deflate the cuff until the tapping sounds cease.

. he last tapping sound #ou hear indicates the diastolic pressure.

Measuring Pulse

"s you ha!e seen, a pulse is measured as the distention of an artery that can befelt each time the heart contracts. 0ulse is measured in number of beats per

minute. 1ou can measure pulse anywhere an artery passes close to the s2in.#linically, it is most common to measure heart rate in the radial artery on the inside

of the wrist. The figure below shows you the procedure.

1. 7lace #our index and middle fingers in the groove on the inside of the wrist. 8ust slide #our

fingers across the tendons until the# slip into soft tissue.

2. "ait until #ou clearl# feel beats coming with a regular rh#thm.

5. 9ount the number of beats for 1: seconds and multipl# b# orfor 5* seconds and multipl# b# 23 to get the number of beats perminute.
http://tmp/svi11.tmp/


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Design of the Experiment I

The rate of circulation can be affected by external conditions such as exercise orother acti!ities that affect metabolism, and the efficiency of the circulatory system

is often related to the health of the indi!idual.In your laboratory you will do fi!e different tests of cardio!ascular fitness and

assign fitness points based on the results of each test. In general, in a fit indi!idualpulse and blood pressure are lower and will return more *uic2ly to the resting

condition after exercise than in a less fit indi!idual. "mong your classmates, youcan expect distance runners and swimmers, for instance, to show a high degree ofcardio!ascular fitness.

Analysis of esults I

The tests that you do in your laboratory enable you to see how cardio!ascularfitness is affected by !arious conditions. The following *uestions will help reinforce

your understanding of circulatory system function and fitness.

1. "h# does increased ph#sical activit# raise heart rate;

he muscle cells re


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1. "hich of the following has the L@4& effect on blood pressure in a #oung adult;

a.

emperature of the room

b.

7osition of the bod#

c.

Level of conditioning

d.

&upplemental vitamins

&orr#. he correct answer is a. 4ll other factors affect blood pressure.2. 4n individual0s blood pressure is reported as 11*+:*. "hich of the following is correct;

a.

he pressure during the contraction phase of the heart is :*, and the pressure duringthe relaxation phase is 11*.

b.

stolic pressure is 11* and diastolic pressure is :*.

c.

he pulse is 11* during exercise and :* when at rest.

d.

he individual shows possible borderline high blood pressure.

9orrectA he correct answer is b.

5. "hich of the test results would be most t#pical of a wellconditioned athlete;

Resting Pulse Resting BP Return to Resting Pulse After Vigorous Exercise

a. C2 15*+D* 2 minutes

b. 11*+* 5* seconds

c. EE 12*+D: E* seconds

d. 11*+C: D* seconds


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a.

a

b.

b

c.

c

d.

d

&orr#. he correct answer is b. 4 low resting pulse, low blood pressure, and a


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Key Concepts II: %emperature and Meta"olic Acti&ity

In the #ellular 3espiration laboratory, you experimented with peas and saw how therate of oxygen consumption during cellular respiration !aried with temperature. Inthat lab, you experimented with peas to see how the rate of oxygen consumption

during cellular respiration increased with temperature.

In animals, an increase in cellular respiration triggers homeostaticmechanisms thatincrease both breathing and heart rate, resulting in more oxygen being a!ailable tocells.

In the second part of this lab, you will study the relationship between temperatureand metabolic acti!ity in an ectothermic animal. "n ectothermis an animal whose

body temperature is much the same as its surroundings, such as a frog, a cric2et,or a sna2e.

To learn more about how ectothermic beha!ior relates to temperature, ta2e a sidetrip to Thermoregulation.

%hermoregulation

Thermoregulationis the maintenance of internal temperatures within a range that

allows cells to function. It may in!ol!e both physiological and beha!ioraladaptations. )or example, humans thermoregulate by sweating and shi!ering, dogs

by panting, and sna2es by bas2ing on sunny roc2s.

Because ectotherms0 temperature remains close to that of theirenvironment, the# face special challenges in thermoregulation.

@ctotherms exhibit a variet# of behaviors that allow them to gainor lose heat. @xamples include basking in the sun and burrowingin mud. Because metabolic rate increases with increasingtemperature, ectotherms do not become active until their bod#has absorbed heat and warmed up. his accounts for the sluggishearl# morning behavior of ectotherms such as snakes.
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Measuring %emperature and Meta"olic ate

The rate of metabolism in ectothermic animals increases as the en!ironmental

temperature increases. This rise occurs because the reactants in the cell ha!egreater thermal energy, and many cellular enzymes are more acti!e as temperature

increases. This effect is noticeable in a range from approximately 45# to 645#7 at

temperatures much higher than this, enzymes become denatured.

The graph below illustrates the effect of increased temperature on metabolic rate inan a*uatic ectotherm, Daphnia magna$water (flea(%.

"hat is the relationship between metabolic rate and a1*F9 increase in temperature;

@ach 1*F9 increase in temperature results in adoubling of the metabolic rate.

The relationship between temperature and metabolic rate is often measured as 8+-.

If the metabolic rate doubles with a +-5# increase in temperature, then 8+-9 .

Design of the Experiment II

It is possible to measure metabolic rate indirectly by measuring heart rate. In thisacti!ity, you will gauge the effect of temperature on metabolic rate by counting the

heartbeats of Daphnia.

There are a number of possible procedures for (trapping( the Daphniaso that you

can obser!e its heart under a dissecting microscope. 1our instructor will show youthe procedure to use.

bser!e the Daphniain a petri dish of water at three different temperatures. elect

each magnifying glass to practice timing the Daphniaheart rate.


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The time on the stopwatch represents +- seconds. #ount the number of heartbeats

during this time and multiply by six to get the heart rate for one minute. 3ecord thenumber7 you will need it for the next exercise.


The time on the stopwatch represents +- seconds. #ount the number of heartbeatsduring this time and multiply by six to get the heart rate for one minute. 3ecord the

number7 you will need it for the next exercise.
http://tmp/svi11.tmp/


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The time on the stopwatch represents +- seconds. #ount the number of heartbeatsduring this time and multiply by six to get the heart rate for one minute. 3ecord the

number7 you will need it for the next exercise.

Analysis of esults II

nce you ha!e !iewed each animation, record the Daphniaheart rate at eachtemperature in the data table below.

"fter you clic2 the (#hec2 "nswer( button, the data you should ha!e obtained willbe shown abo!e. ;id you remember to multiply by < to get the beats per minute= If

you did not label the axes correctly, return to the pages in your lab manual thatdiscuss independent !ariablesand dependent !ariables.
http://tmp/svi11.tmp/http://tmp/svi11.tmp/


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!a" #ui$ II

1. "hich of the following organisms would show the greatest fluctuation in bod# temperaturehour b# hour;

a.

dolphin

b.

mouse

c.

lake trout

d.rattlesnake

&orr#. he correct answer is d. 4lthough a lake trout is also ectothermic, its a


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5. !f G1*- 2, then an en)#matic reaction that takes place at a given rate at :F9 would take placeapproximatel# how man# times faster at 2:F9;

a.

went# times

b.

@ight times

c.

>our times

d.

hree times

e.

wo times

&orr#. he correct answer is c. @ach 1*F9 increase in temperature results in a doubling of themetabolic rate.

. "hich of the following experimental conditions would be most lifethreatening for anectothermic organism;

a.

emperatures that exceed *F9

b.

emperatures that are between 5F9 and F9

9orrectA =igh temperatures result in permanent changes to en)#me structure that disrupt normal

cellular functions.

57535019 circulatory physiology

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