science 30 unit a living systems respond to their environment...
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Science 30 – Unit A – Living Systems Respond to Their Environment
Science 30
Unit A – Living Systems Respond to Their Environment
General Outcome 1: Students will analyze how the human circulatory system facilitates
interaction between blood cells and the external environment and investigate
cardiovascular health.
Specific Outcome 1.1: Describe the principal structures and associated blood
vessels of the heart.
Specific Outcome 1.2: Describe the rhythmic contraction of the heart and its
function in the general circulation of blood through pulmonary and systemic
pathways.
Specific Outcome 1.3: Describe the structure and function of the blood vessels
and the flow of blood through arteries, arterioles, venules, veins and capillaries.
Specific Outcome 1.4: Describe the main components of blood and their role in
the transportation of substances, blood clotting, the defence against pathogens
and the distribution of thermal energy.
Textbook reference pages: p. 6 – 41 in Science 30
CIRCULATORY SYSTEM (CARDIOVASCULAR SYSTEM)
The circulatory system is the body’s internal transportation system that includes the
heart, the blood vessels and the blood.
The circulatory system has 4 main functions:
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Science 30 – Unit A – Living Systems Respond to Their Environment
1.1 THE HEART
About the size of your fist
Located in the centre of your chest (behind the sternum
bone)
Composed of two parallel pumps
Separated by the septum (blood from either side never
mixes)
Right side pumps blood to the lungs
Left side pumps blood to the body
Each pump is composed of two chambers
o An atrium (welcomes blood to the heart)
o A ventricle (pumps blood out of the heart)
Valves connect the atria to the ventricles
Valves allow blood to flow down only (from atrium to
ventricle)
I am an amazing
muscle that beats
about 70 times
every minute.
CORONARY ARTERIES – the vessels that
supply the heart muscle with oxygen-rich
blood.
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Science 30 – Unit A – Living Systems Respond to Their Environment
HEART ANATOMY
SEPTUM – the thick wall of muscle that divides the left and the right sides of the heart
ATRIUM – the smaller upper chamber that receives blood returning to the heart
VENTRICLE – the larger V-shaped bottom chamber that pumps blood from the heart
HEART VALVES – thin flaps of tissue in the heart that open and close to ensure the proper
direction for blood flow
2007 Alberta Education
Name: __________________________________
Science 30 – Unit A – Living Systems Respond to Their Environment
RIGHT
VENTRICLE
• Receives oxygen poor blood from the contraction
of the right atrium causing the valve to open
PULMONARY
ARTERY
• Receives oxygen-poor blood from the contraction of the right
ventricle causing the valve to open sending the blood to the
lungs to be oxygenated
PULMONARY
VEINS
• Receives oxygen-rich blood from the lungs and returns it to the
heart
LEFT
ATRIUM • Receives oxygen-rich blood from the pulmonary veins
RIGHT
ATRIUM
• Receives oxygen-poor blood from the body
through the vena cavae
LEFT
VENTRICLE
• Receives oxygen-rich blood from the contraction of the left
atrium causing the valve to open; has a much more muscular
wall as it pumps blood to the whole body
AORTA • Receives oxygen-rich blood from the contraction of the left
ventricle causing the valve to open sending oxygenated
blood to the body; largest artery in the body
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Science 30 – Unit A – Living Systems Respond to Their Environment
Practice:
Label the diagram
Pg. 19 #1-6
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Science 30 – Unit A – Living Systems Respond to Their Environment
1. Beginning with the vena cavae, the order of the structures of the cardiovascular
system through which blood flows is as follows: vena cavae, right atrium, right
ventricle, lungs, left atrium, left ventricle, aorta, and body.
2. a. IV The pulmonary veins receive oxygenated blood from the lungs.
b. II The aorta sends oxygenated blood to the body.
c. V The semilunar valve prevents the backflow of blood into the heart.
d. VI The septum separates the right and left halves of the heart.
e. I The vena cavae collects deoxygenated blood from the body.
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Science 30 – Unit A – Living Systems Respond to Their Environment
b. Regular cardiovascular exercise increases the elasticity of the heart tissue—this gives
the heart a greater capacity to expand and, therefore, a larger stroke volume. Since
the stroke volume is larger, an increased volume of blood is pumped to the body during
each of the heart’s cycles, so the athlete’s body can get the necessary amount of
blood with fewer heartbeats. An inactive person tends to have a heart with less elastic
tissue, so this heart has a decreased ability to expand and, therefore, a reduced stroke
volume. This reduction in blood volume pumped to the body during each of the heart’s
cycles means that it takes more heartbeats every minute to supply the body with the
required amount of blood.
4. The left ventricle of the heart pumps blood to the body and needs to do so with
significant force, whereas the right ventricle needs to pump blood only to the
lungs. Therefore, the left ventricle is much more developed.
5. The systole is the complete contraction of one of the heart’s chambers. A
ventricular systole occurs when the ventricles contract, while an atrial systole
occurs when the atria contract. The diastole is the relaxation stage of the heart’s
cycle, when neither the ventricles nor the atria are contracting. Together, the
systole and diastole make up one complete heartbeat.
6. A heart-rate monitor is used to help an exercising person maintain a desired
exercise intensity as determined by the heart rate. The intensity could be used to
aid weight loss and/or an increased cardiovascular performance, or it could be
used to ensure that the heart rate remains at a safe level.
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Science 30 – Unit A – Living Systems Respond to Their Environment
1.2 CIRCULATION PATHWAYS AND HEART BEAT
The heart is made up mostly of muscle cells that contract
on their own and in unison (“myogenic tissue”)
Specialized nerve tissue helps to coordinate the muscle
contractions
Both sides of the heart fill with blood at the same time
and work as parallel pumps
Both atria will fill with blood and contract at the same
time, the valves will open allowing blood to flow to
the ventricles
Both ventricles will then simultaneously contract
There are 3 vascular loops in the circulatory system:
Pulmonary system (lung loop)
o From the heart to the lungs and back
o Picks up O2; dumps CO2
Systemic system (body loop)
o From the lungs to the whole body and
back
o Picks up CO2; dumps O2
Coronary system (heart loop)
- Electrocardiograms (ECG or EKG)
are machines used to monitor the
heart.
- When the ventricles are contracting
randomly and ineffectively (like a
spasm), it is called ventricular
fibrillation; an electric shock from a
defibrillator can jolt the heartbeat
back into rhythm.
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Science 30 – Unit A – Living Systems Respond to Their Environment
The heart beat has two phases:
1. DIASTOLIC – the atria and ventricles are relaxing filling with blood; the semilunar
valves close causing a “dub” sound
2. SYSTOLIC – the atria and the ventricles contract forcing blood to move; the
artrioventricular valves close causing a “lub” sound
BLOOD PRESSURE
The force per unit area that blood exerts on the walls of blood vessels.
It is measured by a sphygmomanometer
It is measured in millimetres of mercury (mm Hg)
It is given as systolic over diastolic pressure
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Science 30 – Unit A – Living Systems Respond to Their Environment
Normal range for blood pressure:
90 to 135 systolic
50 to 90 diastolic
120/80 is the “textbook” normal pressure
Hypertension is chronic abnormally high pressure above 140/90
MEASURING BLOOD PRESSURE:
Put the inflatable cuff around the upper arm and inflate to a pressure of about
145 – 160 mm Hg. This blocks the flow of blood in the major artery.
Using a stethoscope, listen for the sound of the blood in the artery. As the
pressure is slowly reduced, blood forcing its way through the artery is heard. This
FIRST SOUND heard is the pressure recorded as the systolic value.
When the sound is no longer heard, the pressure value is recorded – this is the
diastolic pressure.
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Science 30 – Unit A – Living Systems Respond to Their Environment
1.3 BLOOD VESSELS
1. ARTERIES:
o carry blood away from the heart under high pressure
o have muscle tissue and elastic fibres
o ARTERIOLE: a small artery that connects an artery to a capillary
2. CAPILLARIES
o site of exchange between tissue cells and the blood
o vast networks of thin blood vessels
o blood cells move in single file
o capillary bed is a network of capillaries in a particular part of the body
3. VEINS
o carry blood to the hear under low pressure; have one-way valves to
prevent backflow of blood
o VENULES connect capillaries to veins
o have wide openings surrounded by thin muscle and connective tissue
o contractions of muscles also helps move blood up veins in the legs back
to the heart
high pressure blood
flowing into capillary
from arteriole
low pressure blood
flowing into venules
from capillary
tissue cells
spaces between tissue
cells to allow diffusion
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Science 30 – Unit A – Living Systems Respond to Their Environment
Practice:
Label the diagram
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Science 30 – Unit A – Living Systems Respond to Their Environment
Pg. 33 # 1-6
1. The following table compares arteries, veins, and capillaries.
Arteries Veins Capillaries
2. a. People with diabetes would no longer have to inject themselves with insulin. Using
an inhaler would be a much less painful and invasive delivery system, and there would
be less chance of infection from poor sanitation at the injection site or scarring from
repeated injections. In terms of disposal and safety, it is much more convenient to carry
around an inhaler than it is to carry syringes.
b. The path from fat under the skin is as follows: a fat capillary under the skin; a venule;
a vein; the vena cava; the right atrium; the right ventricle; the pulmonary arteries; the
lungs; the pulmonary veins; the left atrium; the left ventricle; the aorta; several arteries;
an arteriole; and end at a capillary next to a target cell in the liver.
c. Inhaled insulin would take the following path from the lungs to a target cell in the
liver: the lungs; the capillaries and venules of lung tissue; the pulmonary veins; the left
atrium; the left ventricle; the aorta; several arteries; an arteriole; and then to a capillary
next to the target liver cell.
d. The inhaled delivery system would be faster because the needed chemical would
not have to first travel through the de-oxygenated parts of the circulatory system. This
quicker delivery would be an advantage over the hypodermic delivery system.
3. Factors that can cause a person’s blood pressure to increase include a stronger
contraction of the heart, a higher heart rate, and a loss in the elasticity of the arteries.
Higher blood pressure readings can also be attributed to anxiety level, exercise, a
greater than normal amount of blood in vessels, viscosity (thickness) of the blood,
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Science 30 – Unit A – Living Systems Respond to Their Environment
chemicals such as caffeine or epinephrine, kidney disease, or a narrowing of the blood
vessels due to a poor diet.
4. If an artery is cut, the greater pressure in an artery means that the blood flows out
more quickly and forcefully than it would in a vein. It follows that there is a greater risk of
blood loss with a cut artery than there is with a cut vein.
5. The following illustration is a sketch of a capillary bed.
6. Contracting muscles in the lower legs help to massage the blood in the lower legs
back toward the heart. Once the leg muscles push the blood in the veins, the valves
are able to direct this blood.
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Science 30 – Unit A – Living Systems Respond to Their Environment
1.4 BLOOD COMPOSITION
The blood is a tissue (made of cells), a fluid called plasma and blood proteins.
The cells include red blood cells, white blood cells and platelets.
Plasma is mainly water with dissolved solutes (e.g. glucose, amino acids).
PLASMA
Yellowish liquid with dissolved or suspended substances
that makes up more than half of blood.
91% water, 7% proteins, 2% nutrients
Transports substances in the blood
WHITE BLOOD CELLS (a.k.a. leukocytes)
part of the immune system (fight disease)
made from special cells in the bone marrow
much larger than red blood cells but are fewer in
number
have a nucleus
PLATELETS
Platelets are small (1/5 size of red blood cells) with an irregular shape
the sticky surface lets them form clots to stop bleeding
RED BLOOD CELLS (a.k.a. erthrocytes)
most numerous (5 million per mm3 of blood) cell type in blood – most common
blood cell in healthy people
carry oxygen using hemoglobin
“bi-concave” shape
no nucleus (enucleated)
develop in the bone marrow and have a life span of about 120 days before
being recycled by white blood cells
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Red blood cells biconcave
shape allow them to slide
through the blood vessels with
ease.
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White blood cells lack a
colour pigment and only
has a life span of 13 – 20
days.
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Platelets call on a protein
to produce FIBRINOGEN,
present in the plasms, to
clot blood.
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Science 30 – Unit A – Living Systems Respond to Their Environment
ROLE OF BLOOD COMPONENTS
1. TRANSPORTATION
HEMOGLOBIN (Hb)
Hemoglobin is an iron-containing pigment that binds oxygen to facilitate its
movement in the circulatory system.
Each red blood cell contains hundreds of millions Hb molecules – the lack of a
nucleus allows for a red blood cell to carry the extra hemoglobin.
As blood passes through the lungs, the hemoglobin molecules picks up oxygen
to form oxyhemoglobin. The oxygen is transported to the body tissues through
the capillary beds.
Carbon monoxide binds irreversibly to hemoglobin thereby inactivating it
Draw a diagram to show the transport of oxyhemoglobin to the body tissues (refer to
page 37).
PLASMA
Holds and transports
o Cells of the blood
o Dissolved waste carbon dioxide from capillaries to the lungs
o Urea – a waste product from the liver, filtered by the kidneys to become
urine
o Hormones from glands
o Digested nutrients such as glucose, amino acids, vitamins and minerals
o Proteins such as antibodies (involved in the immune system) and
fibrinogen to aid in blood clotting
2007 Alberta Education
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Science 30 – Unit A – Living Systems Respond to Their Environment
2. BLOOD CLOTTING
Platelets are responsible for clotting the blood.
Fibrin is a thread-like insoluble protein formed from firbrinogen.
A blood clot is a jelly-like, solid mass of red blood cells caught up in a net of fibrin
fibres.
PROBLEMS WITH BLOOD CLOTTING
o High fat diets can lead to artery walls becoming rough causing platelets
to stick and produce a blood clot in the artery.
o Blood clots in the arteries can lead to heart attacks or strokes.
o Hemophilia is a blood disorder that inhibits ability for the blood to clot,
which may lead to excessive bleeding.
3. DEFENSE AGAINST PATHOGENS
White blood cells increase in number when disease-causing organisms enter the
body.
The increase in the white blood cells helps the body fight off infections.
4. DISTRIBUTION OF THERMAL ENERGY
To keep the thermal energy distributed evenly throughout the body, blood acts
as a convective fluid to keep the tissues of the body from overheating.
Hormones such as epinephrine, norepinephrine, and thyroid hormone are
carried through the circulatory system to help with heat in the body.
Practice:
Pg 41 #1, 3, 4, 5
When the skin is
cut, blood starts
leaking out to
wash away dirt
and germs
Platelets rupture
and convert
fibrinogen into
threads of fibrin
Red blood cells
get caught in the
fibrin net to form a
blood clot
The clot hardens
to form a
protective scab
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Science 30 – Unit A – Living Systems Respond to Their Environment
1. a. The four components of blood from most abundant to least abundant are plasma,
red blood cells, white blood cells, and platelets.
b. The following diagram illustrates each component of question 1.a.
3. Carbon monoxide has a much greater affinity for hemoglobin than does oxygen, so
carbon monoxide will preferentially bind to hemoglobin and form a stable bond. As a
result, if you inhale even low concentrations of carbon monoxide, more hemoglobin
combines with carbon monoxide than does oxygen. If carbon monoxide is taking the
place of oxygen on the red blood cells, that means that the blood cannot transport
needed oxygen to the body’s cells. A person could suffocate even though he or she is
able to breathe normally.
4. Anticoagulants that thin blood make it easier for blood to flow through damaged or
constricted blood vessels.
5. a. Having improperly functioning white blood cells means that the person is not able
to fight off disease-causing organisms.
b. A transplant of healthy bone marrow means that healthy and normally functioning
white blood cells will be produced.