Bio 102 Lab 03: Hematology and Circulation

Bio 102 Lab 03: Hematology and Circulation

By Jill Caporale and Christopher Eninger

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Overview

Animals too large to accomplish internal transport by diffusion are equipped with a system of branching vessels filled with blood, which is usually propelled through the system by the muscular contractions of the heart. Vertebrates have a closed circulatory system—a circuit of continuous vessels. Other animals, such as arthropods and annelids, have an open circulatory system: blood flows from vessels to open spaces in the tissues and then to vessels again. A pump is used to move the blood throughout the vessels of the circulatory system.

Many organisms couple the circulatory system with a respiratory surface such as lungs or gills, where gases can be exchanged between the blood and the environment. In vertebrates other than birds and mammals, a serial circuit delivers blood directly from the respiratory surface to the tissues. The parallel circuitry (pulmonary and systemic systems) present in birds and mammals is more efficient.

Blood traveling in the circulatory system is made up of a fluid matrix called plasma, which carries cells, oxygen, nutrients, wastes, and other materials from one region of the body to another. Blood often contains special respiratory pigments that deliver the oxygen throughout the body. The rate at which the blood is pumped by the heart can be measured as one’s pulse. Blood pressure is a measure of the force exerted by blood against the walls of the blood vessels. Both pulse and blood pressure can be influenced by a variety of factors, including diet, exercise, hormones, age, smoking, alcohol intake, and a number of other environmental factors.

During this laboratory, you will investigate the properties of blood cells, learn the path taken by blood through the heart and lungs, take your pulse, and learn what blood lab values mean.

Section A – Hematology

Part 1 – Hematology – Blood cells

Blood contains white cells (leukocytes) and red cells (erythrocytes). Mature mammalian erythrocytes are biconcave disks that lack a nucleus and contain hemoglobin for the transport of oxygen. Leukocytes are nucleated cells. Granulocytes and monocytes, types of leukocytes, transform into macrophages that migrate to infected areas, where they perform a clean-up function. Lymphocytes, another type of leukocyte, are responsible for immune reactions. Many infections are characterized by an increase in the white blood cell count.

1. Observe the photograph of a prepared slide of human blood. Use Figure below to help identify cell types.

Human Blood Slide

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© Carolina Biological

a. On this slide, which type(s) of blood cells lack(s) nuclei?

b. On your slide, which cell type is most abundant?

c. Which type of white blood cell (leukocyte) is most abundant?

d. Granulocytes are characterized by nuclei of many different shapes and by the granules in their cytoplasm. What color are these granules? Why do the granules have this color?

2. Examine the slide of blood from a carrier of sickle-cell anemia in low-oxygen crisis.

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a. Make a sketch of several abnormal red blood cells.

b. Healthy red blood cells are round. Are all the red blood cells on your slide round?

c. How do you think the abnormal shape of some of the red blood cell would interfere with circulation?

The hemoglobin of an individual who carries the recessive sickle-cell allele in the heterozygous condition is less soluble than normal hemoglobin. When the oxygen supply is inadequate or when the carbon dioxide concentration increases, sickle-cell hemoglobin molecules tend to crystallize to form hair-like rods that pile up and transform the cell into a sickle shape. The cells then clump and clog the blood vessels and cannot carry out their function of transporting oxygen. To determine whether a person is a carrier of the sickle-cell allele, blood is subjected to a low-oxygen atmosphere and examined with a microscope. In an individual who is homozygous for the sickle-cell allele (that is, has sickle-cell anemia), hemoglobin is abnormal even at normal oxygen and carbon dioxide concentrations.

3. Mononucleosis is a disease characterized by fever, headache, scratchy throat, easy fatigue after minimal exertion, and enlargement of the lymph glands.

Examine the blood slide from a person with mononucleosis.

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Do some of the white blood cells look abnormal? How?

4. Examine a prepared slide of frog blood.

BFrog blood slide, smear

How do frog erythrocytes differ from those of humans?

Part 2 – HEMATOLOGY – Analysis of Complete blood counts WHAT ELSE CAN YOUR BLOOD TELL YOU ABOUT YOUR HEALTH?

Blood has many compounds and enzymes that provide a window into a person’s health.

As part of a full checkup a complete blood count (CBC) is often conducted. Typical tests included in a CBC are shown below in the chart from the National Heart, Lung and Blood Institute (a part of the National Institutes of Health in Bethesda, Maryland). In addition to these standards, additional tests may be carried out depending upon your risk factors or symptoms. A second blood test may be ordered to further investigate abnormal results of an initial blood test.

Test

Normal Range Results*

Red blood cell (varies with altitude)

Male: 5 to 6 million cells/mcL

Female: 4 to 5 million cells/mcL

White blood cell

4,500 to 10,000 cells/mcL

Platelets

140,000 to 450,000 cells/mcL

Hemoglobin (varies with altitude)

Male: 14 to 17 gm/dL

Female: 12 to 15 gm/dL

Hematocrit (varies with altitude)

Male: 41% to 50%

Female: 36% to 44%

Mean corpuscular volume

80 to 95 femtoliter†

* Cells/mcL = cells per microliter; gm/dL = grams per deciliter.
† A femtoliter is a measure of volume.

Blood Glucose

This table shows the ranges for blood glucose levels after 8 to 12 hours of fasting (not eating). It shows the normal range and the abnormal ranges that are a sign of prediabetes or diabetes.

Plasma Glucose Results (mg/dL)*

Diagnosis

70 to 99

Normal

100 to 125

Prediabetes

126 and above

Diabetes†

* mg/dL = milligrams per deciliter.
† The test is repeated on another day to confirm the results.

Lipoprotein Panel

The table below shows ranges for total cholesterol, LDL (“bad”) cholesterol, and HDL (“good”) cholesterol levels after 9 to 12 hours of fasting. A high LDL/HDL cholesterol ratio is a risk factor for coronary heart disease.

Total Cholesterol Level

Total Cholesterol Category

Less than 200 mg/dL

Desirable

200–239 mg/dL

Borderline high

240 mg/dL and above

High

LDL Cholesterol Level

LDL Cholesterol Category

Less than 100 mg/dL

Optimal

100–129 mg/dL

Near optimal/above optimal

130–159 mg/dL

Borderline high

160–189 mg/dL

High

190 mg/dL and above

Very high

HDL Cholesterol Level

HDL Cholesterol Category

Less than 40 mg/dL

A major risk factor for heart disease

40–59 mg/dL

The higher, the better

60 mg/dL and above

Considered protective against heart disease

· The table above is from The National Heart, Lung and Blood Institute of the National Institutes of Health.

LDL (low density lipoproteins) and HDL (high density lipoproteins) both carry cholesterol in your body. LDLs carry cholesterol to the cells of your body but can cause a buildup of plaque within your blood vessels, hence LDLs are referred to as your “bad” cholesterol. HDLs carry cholesterol to your liver for processing and removal from your body and are thus referred to as “good” cholesterol. Therefore, it is important to look not only at the total cholesterol but the ratio of “bad” LDL to “good” HDL. The higher the number the higher the risk for heart disease.

Use the charts above and information learned in the lab to answer the following questions concerning tests found in a complete blood count.

1. Why do you think hemoglobin levels vary with altitude?

2. High levels of what substance found in the blood can determine diabetes and

prediabetes?

3. High cholesterol and triglycerides may indicate cardiovascular disease. What happens when cholesterol and other lipids are deposited in artery walls? When this happens, what is the process called?

SECTION B – Circulation

Part 1 – Evolutionary Circulation

The circulatory system is responsible for the movement of nutrients within the bodies of many animals. It takes many forms across the animal kingdom, but most contain at least one heart, which pumps the fluid keeping it moving. The first big distinction is an open versus a closed system.

In an open circulatory system the blood or hemolymph is not contained in vessels but bathes the organs & the heart’s job is just to keep it moving, preventing “dead spaces” from occurring where the fluid sits in one place too long becoming nutrient depleted resulting in local tissue death. Many animals with open circulatory systems also have multiple hearts and most don’t use their hemolymph to transport oxygen or carbon dioxide. Many invertebrates have open circulatory systems, including insects, crustaceans, & arachnids.

In a closed circulatory system the fluid is contained inside of blood vessels at all times. The heart is used to pump the fluid in a distinct pathway. Closed systems have 3 distinct vessel types. Arteries, which are thick walled that take the blood away from the heart. Veins, which have thin walls and often have valves to prevent back-flow as they return the blood to the heart. Connecting arteries and veins far from the heart are capillaries, which are very thin walled (often a single layer of cells) and are designed for nutrient exchange. Animals with closed circulatory systems also use their fluid to deliver oxygen & remove carbon dioxide. Examples include birds, mammals, fish, cephalopods (squids & octopuses), amphibians, reptiles, & annelids (earthworms).

The next division of types of circulatory systems is found within the vertebrates, who all have closed systems. They are divided up by the number of chambers they have in their hearts & if the heart completely separates oxygenated & deoxygenated blood. Allowing mixing of the oxygenated & deoxygenated blood makes for an inefficient system, however, if the system isn’t organized correctly, there can be problems with systems that do separate oxygenated & deoxygenated blood.

Reptiles & amphibians both have 3 chambered hearts. They have 2 upper filling chambers, called atria, which pump blood into a single ventricle (larger, pumping chamber). One atrium collects blood that is returning from the body, thus low in oxygen, & the other collects blood that has just gone to the lungs and is thus oxygen rich. This ventricle pumps both to the lungs & to the rest of the body. As the atria empty into the ventricle together, this blood mixes, meaning some of the blood goes to the lungs when it is oxygenated, & some that is deoxygenated goes to the body again. Naturally, this creates a problem with efficiency.

Fish, birds, & mammals all have complete separation of oxygenated & deoxygenated blood. However, the fish have another problem. Their 2 chambered heart (1 atrium & 1 ventricle) pumps to the gills & then the blood continues onto the rest of the body, without having a second pump. As the gills have capillaries, with their very thin walls, they can’t have a high blood pressure or the gill capillaries would rupture. This means the blood, under very low pressure, has to go from the gills to the rest of the body & back to the heart again. This creates a problem with oxygen delivery & makes it hard for fish to get large quantities of oxygen to their bodies swiftly.

Birds & mammals both have 4 chambered hearts (2 atria & 2 ventricles). The heart is divided into a left & right side, each with one upper filling atria & one lower pumping ventricle. The right side collects blood from the body & sends it to the lungs to get oxygenated, returning the blood to the left side, while the left side pumps to the body, returning the blood to the right side. The right side is often called the pulmonary circuit & the left side is often called the system circuit. Effectively this makes the heart into a double pump, one side pumping blood to get oxygenated & the other side pumping nutrients to the body.

The cardiac cycle is the rhythm of how the heart beats. In one cardiac cycle, the heart will have one emptying phase, called systole, & one filling phase called diastole. The amount of blood the heart pumps in a single cycle is the stroke volume. While the heart can change the stroke volume rapidly between cycles, doctors are often interested in how much blood the heart pumps in a minute, called the cardiac output. The other variable that can change your cardiac output is the heart rate, or how many times your heart beats in a minute.

Exercise 1 – Identifying the structures of the human heart

Use the drawing of the human heart below. Refer to your textbook, or online sources, for alternate angles to view the heart. You may have to compare multiple drawings/photos to properly orient yourself.

Exercise 2 – Changes in heart rate

Supplies

Timer, stopwatch, or clock

Procedure

1. Find your pulse, either in your neck or in your wrist. If you have not found your pulse before, use the internet to find a video describing where to take your neck or wrist pulse. Practice measuring your heart rate for 15 seconds a few times until you feel comfortable locating your pulse and with the timing.

2. Lay down, on your back for 3 minutes. After 3 minutes have passed, take your heart rate for 15 seconds. Measure your pulse for 15 seconds, 2 more times (3 total 15 second measurements). Record the results in the table below without standing or sitting up!

3. Sit up and immediately measure your heart rate for 15 seconds. Record the results

4. Sit still for about 1 minute and take your heart rate for 15 seconds.

5. Again sit still for 1 more minute and take your heart rate over 15 seconds Record the sitting heart rates again in the table below.

6. Stand up and immediately take your heart rate for 15 seconds. Stand still for 1 minute. Repeat this 2 more times.

7. Run in place for 2 minutes (make it a strenuous effort, as if you were working out). Immediately after stopping, take your heart rate. Wait 1 minute & repeat. Do this 2 times.

8. Answer the questions on the answers page.

Exercise 3 – The Electrocardiogram (ECG or EKG)

Procedure

1. Watch the following video from the start to 1:20 on the basics of the electrocardiogram. https://www.youtube.com/watch?v=1Q8YSpMcO-8

Exercise 4 – Blood vessels of the human body.

1. Use the pictures below to compare the structure of an artery to a vein.

2. Answer the questions on the answer sheet about the arteries & veins (Exercise 4, below).

Questions & Tables

Label the parts of the heart below

Exercise 2 Table

Body Position

HR #1

15 seconds

HR #2

15 seconds

HR #3

15 seconds

Average

Average *4

(Seconds–>Minutes)

Laying Flat

Sitting

Standing

Post exercise

1. What effect did standing up have on the heart rate?

2. Was there a difference between laying & sitting? Explain why that might be?

3. How did the standing heart rate compare to the laying & sitting heart rates? Why would you expect to see a difference?

4. What effect did the exercise have on the heart rate, when compared to the standing heart rate?

Exercise 3: Refer to a diagram of an EKG in your textbook.

For an EKG explain what is happening at (& between) each peak in your own words.

P-wave:____________________________________________________________________________

P-Q Interval:________________________________________________________________________

QRS Complex:______________________________________________________________________

__________________________________________________________________________________

S-T Interval:________________________________________________________________________

T wave:____________________________________________________________________________

T-P Interval:_________________________________________________________________________

1. If the P peak was really missing, how would this affect a person’s heart beat?

_______________________________________________________________

Exercise 4. Answer the following questions.

1. What is the difference in terms of function & structure for arteries & veins?

2. Does the difference in structure for arteries & veins make sense given then functions? Explain.

3. Which artery carries deoxygenated blood in adult humans? Where is this artery traveling (both to and from)?

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Bio 102 Lab 03: Hematology and Circulation

 

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