Worksheet

How a Blood Donor's Body Refills

Grade 6 life science: a blood donor's heart rate and hemoglobin checks and an iron study show how digestive, circulatory, nervous and other systems interact.

Grade 6ScienceInteractive · Printable

Aligned toMS-LS1-3

Play online Play as a game

PrintLetter-size worksheet Answer keyPrintable answers

Assign to classAssign to your classes, or get a join code

What’s included

Single worksheet
Auto-graded online
1 NGSS standard
Printable answer key
11 questions
Classroom-ready

Details

Format: Interactive · Printable
Grade: Grade 6
Subject: Science
Question types: Fill in the blank, Multiple choice, Sorting, Short answer

About this worksheet

What students practice

Students use heart rate and hemoglobin data to explain how body systems respond after blood loss.
Students argue from evidence that the digestive, circulatory, nervous and urinary systems interact.
Students explain why a two-group study isolates the effect of iron.

How to use

Read the passage aloud and sketch the path of water and iron from the intestine to the blood before students start; use the final note as a short writing task.

Curriculum

NGSS standard covered

MS-LS1-3

Argue how the body is a system of interacting subsystems, from cells to tissues, organs and organ systems.

Preview

OwlSheets.com

Name Date

How a Blood Donor's Body Refills

Use a donor's checks and a hospital study to argue how body systems interact.

Darius's checks

Read the passage and Table 1, then answer the questions.

A Day at the Blood Drive

1Mireille Fontaine, a sixth grader, spent a school holiday with her uncle Darius, who is 34 and gives blood twice a year at Lakemont Regional Hospital. The hospital, the people and the numbers here are made up, but they are based on real blood-donation studies. Before Darius donated, nurse Paulina Szabo pricked his finger to check his hemoglobin, a protein inside red blood cells. In the lungs, hemoglobin picks up oxygen, and the blood carries it to cells all over the body.

2Darius's body held about 5.0 L of blood. In about ten minutes, 0.5 L flowed through a tube into a collection bag, and then the nurse removed the needle. He rested and had juice and crackers. An hour later he stood up quickly and felt lightheaded, and his heart rate jumped from 72 to 90 beats per minute within a few seconds. He sat back down, and the feeling passed. Nurse Szabo explained that standing up quickly lets blood pool in the legs for a moment, so the pressure in the upper body dips. Pressure sensors in the walls of large blood vessels in the neck and chest send signals along nerves to the brain, and the brain sends signals that can speed up or slow down the heart.

3About half of blood is plasma, a liquid that is mostly water. Over the next day or two, the body refills the plasma with water that the intestines absorb from drinks and food. Water the body does not need is removed by the kidneys and leaves in urine. Replacing the lost red blood cells takes much longer. The body makes new ones all the time, but each needs hemoglobin, and building hemoglobin takes iron. Iron comes from foods such as beans, meat and leafy greens and is absorbed in the small intestine. The nurse told Darius to drink extra fluids for two days, to skip hard exercise that day and to take one iron pill a day for eight weeks, which he did.

4Mireille checked Darius's heart rate at rest and right after he climbed the same three flights of stairs at the same steady pace. He skipped the stairs on donation day. The hospital also shared a study of 120 healthy adult donors aged 25 to 45. Each gave 0.5 L of blood and got the same advice about food and drinks. Half took a daily iron pill, and half did not.

Table 1. Darius's Checks (heart rates in beats per minute)
When	Resting heart rate	After the stairs	Hemoglobin (g/dL)
Before donating	64	118	14.6
1 hour after	72	not done	14.4
Day 2	68	132	13.6
Week 4	65	125	14
Week 8	64	119	14.5

Use Table 1.

On Day 2, Darius's heart rate after the stairs was beats per minute higher than before he donated.

Use paragraph 2.

Darius gave about % of the blood in his body.

One hour after donating, Darius's hemoglobin had barely changed (14.6 to 14.4 g/dL), but on Day 2 it was 13.6 g/dL. Which explanation fits paragraph 3 best?

A. His kidneys moved hemoglobin from his blood into his urine to make up for the lost plasma.
B. Water absorbed from his drinks refilled the plasma, so his remaining red cells were spread through more liquid.
C. Digesting the crackers and juice used up some of the hemoglobin that was in his blood.
D. The needle kept drawing a little blood from his arm until the morning of Day 2.

Why did Darius's heart beat faster on the stairs on Day 2 than before he donated?

A. The extra fluids gave him more blood than before he donated, so his heart had more to pump.
B. His lungs held less air after donating, so each breath brought in less oxygen.
C. His leg muscles were weaker after donating, so they needed fewer heartbeats to climb.
D. Each liter of his blood carried less oxygen, so his heart pumped more often to supply his legs.

Use paragraph 2. Which order of events best explains why Darius's heart rate jumped when he stood up quickly?

A. Pressure sensors detect the dip → nerves carry signals to the brain → the brain signals the heart to beat faster
B. The brain senses the low pressure → nerves carry signals out to the pressure sensors → the heart speeds up
C. The lungs take in more air → the pressure sensors fill with oxygen → the brain signals the heart to slow down
D. The heart speeds up → pressure sensors detect the faster beat → the brain makes him feel lightheaded

Rebuilding red blood cells

Use Table 2, Table 1 and the passage.

Table 2. Hospital Study: Time for Hemoglobin to Return
Group	Donors	Daily iron pill?	Weeks to return (avg.)
A	60	Yes	7
B	60	No	18

"Weeks to return" means the number of weeks until a donor's hemoglobin was back to its level before donating.

Use Table 2.

On average, Group A's hemoglobin returned to its starting level weeks sooner than Group B's.

Why did the hospital compare two groups of the same size and age range that each gave 0.5 L and got the same food advice?

A. So the hospital could collect twice as much blood that week
B. So each donor could compare heart rates with a partner
C. So the iron pill was the main difference between the groups
D. So the donors would need fewer finger-prick tests

Which explanation of Table 2 fits paragraph 3 best?

A. Iron taken in by the small intestine and carried in the blood let the body build hemoglobin sooner.
B. Iron pills made the kidneys keep more water, so the plasma refilled sooner.
C. Iron pills made the heart beat faster, which pushed new red cells out of the heart sooner.
D. Iron pills carried oxygen straight into the blood, so the body needed fewer new red cells.

Use Table 1, Table 2 and paragraph 3. Sort each change by how long it took after the donation.

Darius's plasma was refilled.Darius's resting heart rate came back to within 5 beats per minute of 64 after its rise at the 1-hour check.Darius's hemoglobin climbed back to within 0.2 g/dL of 14.6 after its Day 2 drop.Darius's heart rate after the stairs came back to within 3 beats per minute of 118.The average Group B donor's hemoglobin was back to its starting level.

Done by Day 2	Took 4 weeks or more

10.

Darius's friend gives blood the same day but skips the juice, drinks very little until the next evening, and then plays a full basketball game. Which prediction fits the passage best?

A. His kidneys would make extra urine during the game, which would refill his blood faster.
B. His heart would likely beat faster than usual in the game, since his plasma would refill more slowly.
C. His hemoglobin would be back to its starting level by the game, since he skipped the sugary juice.
D. His heart rate in the game would match a normal day, since red cells, not plasma, carry oxygen.

11.

Write a short note for next year's first-time donors. Make a claim about why the nurse tells donors to drink extra fluids, take iron if it is advised and skip hard exercise that day. Give evidence from Table 1 and Table 2, and explain how at least three organ systems work together as the body recovers.