Transcript File - singhscience

B2 Topic 3
-The structure of the Heart
-Blood
-The Circulatory System
- Aerobic and Anaerobic Respiration
Starter: Stick in the heart diagram
Structure of the
Heart
Questions in the past have asked:
-Label the structure in the heart
-Describe how blood travels through the heart
- Where the blood flows into and out of the heart
Structure of the
Heart
Right= Blood without
oxygen
(deoxygenated)
Left= Blood with oxygen
(oxygenated)
Where does blood enter the heart?
NEED TO KNOW: Both are Veins
How does blood flow through the heart?
1
1
Step 1: Enters the atrium
How does blood flow through the heart?
2
2
Step 2: Pumped into ventricles
How does blood flow through the heart?
3 3
Step 3: Pumped out of ventricles
Which blood vessels transport blood away
from the heart?
To lungs
To rest of body
Both are arteries
What stops blood flowing backwards in the
heart?
Valves stop blood flowing backwards
Why is the heart called a double pump?
Heart pumps blood to two places;
left side pumps blood to the rest of the body
and right side pumps blood to the lungs
Why do the ventricle walls have different
thicknesses?
Left ventricle has a thicker wall
= Stronger so can pump blood further round the
body
Now lets have a look
at an exam question
about this..........
The diagram shows a human heart
.
(i) Draw an arrow onto the diagram
to show where oxygenated blood
enters the heart.(1)
(ii) Suggest how the blood flowing
through the pulmonary artery would be
different from the blood flowing
through the aorta.(2)
(iii) Describe the role of the valve
labelled on the diagram.(2)
Answer
(i)
(ii)
Any two from the following:

(blood in pulmonary
artery) deoxygenated (1)

(blood in pulmonary
artery) lower pressure (1)
Acceptable
Mark
answers
ignore any labels on
the arrow allow an
arrow coming out of
the opening of
pulmonary vein into
heart
(1)
accept reverse
argument for aorta
carrying less oxygen
/ no oxygen less
force / slower
(2)
(iii)
Any two from the following:

prevent backflow (1)

(from ventricle) into
atrium (1)
description of
backflow ignore
references to left
atrium and
deoxygenated blood (2)
Why do we have a heart?
To transport gases, glucose, nutrients and water
around the body. These are carried by the blood.
Key words:
Components- What something is made up of, i.e. the
components of blood
What are the components of blood?
What do they do?
Carry
Oxygen
Clot the
blood
Answer is always:
DESTROY
PATHOGENS
Plasma - Liquid to
carry the substances
The photograph shows a blood smear from a
healthy person.
Name the two types of blood cells, X and Y, shown in the
photograph.
(2)
.................................................................................................................
.................................................................................................................
(i)
Name the liquid part of the blood.
(1)
Question
Number
Answer
• X - white
blood cell /
phagocyte
(1) • Y red blood
cell /
erythrocyte
(1)
Question
Answer
Number
plasma
Acceptable
answers
Mark
(2)
Acceptable
answers
Mark
(1)
Why does the blood transport
substances around the body?
• Respiration
• Blood transports oxygen and glucose to
cells so they can make energy in
respiration.
• Blood transports carbon dioxide and
waste away from cells.
Respiration
•
•
•
•
Exam questions about respiration could ask you to recall parts of
either equation.
It could also ask you to name the type of respiration based on the
products.
It could also ask you to compare the effects on breathing/heart rate
before and after exercise and why this is important to respiration.
We will look at the equations next and some exam questions.
At the cells
Aerobic Respiration = Lots of oxygen available
Come from blood
Anaerobic Respiration = No oxygen
Exam questions on this topic often involve graphs.
What does it mean?
More exercise
More oxygen
needed by the
cells for
respiration
Heart rate and
breathing rate
will increase
Now lets have a look
at an exam question
about this..........
before exercise
(pulse rate in beats
69
per minute)
after exercise
(pulse rate in beats
per minute)
swimming
98
cycling
sprinting
73
69
110
149
(b) Pearl measures her heart rate during three different types of
exercise.
Explain why the exercises have different effects on her pulse
rate. (3)
Answer
Mark
Question
number
(a)(i)
C
Question
number
(b)
(1)
Answer
an explanation linking the
following: (idea that) the
higher the impact of the
exercise the higher the
pulse rate (1) (idea that)
higher pulse rate means
the heart is beating faster
(1) (idea that) because
there is an increased
energy demand (from
aerobic respiration) for the
high impact sport (1)
(3)
Mark
Cardiac output
• Many exam questions in the past have
asked you to use the cardiac output
equation sometimes linked to reading
information from a table.
• Sometimes they will give you the
equation, but more often than not they
don’t so you will need to learn it.
•
cardiac output = heart rate × stroke volume
Now lets have a look
at an exam question
about this..........
athlete
stroke volume /
beats per
3
dm
minute
cardiac output
/ dm3 min–1
at rest
0.1
53
5.3
182
30.4
during exercise
The volume of blood that the heart pumps with every beat is known
as the stroke volume.
Stroke volume can be used to indicate fitness level.
The table gives information about the stroke volume, heart rate and
cardiac output of an athlete at rest and during exercise.
(a) Calculate the stroke volume of the athlete during exercise. (2)
answer = . . . . . . . . . . . . . . . . . . . . . . . . . . . . Dm3
(b) Explain why it is important that the cardiac output of the athlete
increases during exercise. (3).
Answer
Acceptable answers
Mark

evaluation (1)
30.4 ÷
182

Correct answer
(1)
0.167 / 0.17 / 0.2 (dm3)
give full marks for bald correct
answer, no working ecf allow
correct answer with full number
of decimal points 0.1670329
(2)
(a)
(b) An explanation linking three of the
following points:

muscles working harder /
Ignore references to anaerobic
contract faster (1)
respiration

need more energy (1)

(aerobic) respiration (1)

more / enough / faster
delivery oxygen (1)

more / enough / faster
glucose (to muscles / body) (1)

more / faster removal of
carbon dioxide (1)
(3)