Download Grade 11 College Biology – Unit 3

Grade 11 University Biology – Unit 5 Animal Systems
Human Circulatory System
The CIRCULATORY SYSTEM is the transport system of the body. It has FOUR functions:
 Transport of oxygen and carbon dioxide
 Distribution of nutrients and transport of wastes
 Maintenance of body temperature
 Circulation of hormones
The system consists of THREE general components:
 FLUID in which materials are transported
 System of BLOOD VESSELS or spaces throughout the body in which the fluid moves
 A pump, the HEART, that pushes the fluid through the open spaces.
The heart and blood vessels are commonly called the CARDIOVASCULAR SYSTEM
The circulatory system is a complex network of tissues and organs throughout your body; yet, no cell is
further than TWO cells away from a blood vessel. Thus, there are 96,000 km of blood vessels in your
body to nourish your 100 trillion cells. The heart is no larger than your fist with of mass of about 300
grams; yet, the heart beats about 72 times/minute.
Every minute, 5 L of blood cycles from your heart to the lungs, picks up oxygen and returns to the heart.
Then, the heart pumps the oxygen-enriched blood and nutrients to the tissues of your body.
Why is oxygen so important to
your life?
The circulatory system is two
systems (see diagram).
 PULMONARY CIRCUIT –
The right side of the heart
pumps blood to the lungs
and returns oxygenatedblood to the left side of the
heart
 SYSTEMIC CIRCUIT –
The left side of the heart
that pumps the oxygenate
blood to all parts of the
body and carries
deoxygenated blood back
to the heart.
HEART STRUCTURE
The left and right sides of the heart are separated by a wall of muscle called the SEPTUM
Each side (or pump) consists of a thin-walled ATRIUM and a thick-walled VENTRICLE. The atria
receives blood for the veins and pumps it into the ventricles. When the heart muscles contract, a valve of
the heart prevents blood from flowing backwards
HEART PHYTHMS, SOUNDS and PRESSURE
The heart has two specialized bundles of nerves that control its beating.
 SINOATRIAL (SA) NODE – acts as a pacemaker
 ATRIOVENTRICULAR (AV) NODE – passes the nerve impulses to the ventricles to cause them
to contract in unison.
The heart sound is the closing of the valves. When the atria are relaxed (called DIASTOLE), they fill with
blood. As the atria push blood into the ventricles, the ventricles contract to force blood into the arteries.
This contraction is SYSTOLE. The increase in pressure forces the AV valves to close…creates the LUBB
sound. As the ventricles relax, the pressure inside decreases closing the semilunar valves and
preventing a backward flow of blood. This closing is the DUBB sound.
BLOOD PRESSURE is the pressure exerted on the walls of the arteries when the ventricles of the heart
contract. Blood pressure is measured in mm Hg.
Blood pressure is measured with a SPHYGMOMANOMETER. A stethoscope is used to listen to the
sound of blood entering the artery as air is slowly released from the sphygmomanometer. The pressure
on the gauge of the sphygmomanometer when the sound is first heard is the SYSTOLIC BLOOD
PRESSURE. As the cuff of the sphygmomanometer is deflated, the sound disappears. This is the
DIASTOLIC BLOOD PRESSURE. If your blood pressure is too high, it put stress on the walls of the
arteries which may result in a stroke or heart attack. High blood pressure is called HYPERTENSION.
Low blood pressure is HYPOTENSION can lead to dizziness, blurred vision or loss of consciousness.
BLOOD VESSELS
 ARTERIES carry blood away from the heart
 The AORTA is the largest artery of the body and closest to the heart
 From the arteries, blood flows into smaller blood vessels called ARTERIOLES, and then, smaller
vessels called CAPILLARIES.
 As the capillaries merge, they become larger vessels called VENULES which merge into VEINS.
The veins have valves that only open in one direction to allow blood to flow only to the heart.
Contractions of the muscles surrounding the veins also help blood to flow to the heart

BLOOD COMPONENTS
Component
Structure and Function
Plasma
Fluid medium used to transport dissolved gases, nutrients, wastes and hormones
It also contains proteins. One protein is used for blood clotting. Another contains
antibodies to provide immunity from diseases.
Erythrocytes
Red blood cells that contain hemoglobin that enables oxygen to bind with the cell
Leukocytes
White blood cells that serve to protect the body against foreign substances, microorganisms and toxins.
Some destroy microorganisms by engulfing them, and then, using enzymes to digest
the microorganisms and the leukocyte. Others specialize in producing antibodies that
are part of the body’s immune system.
Fragments of white blood cells and invading microorganisms are PUS
Platelets
Small fragments of larger cells produced from cells in bone marrow
Function primarily to initiate blood clotting
Grade 11 University Biology – Unit 5 Animal Systems
Parts of the Circulatory System
ANSWERS
Part
Structure / Location
Function
Vein
large blood vessel / thin walled
carries blood TO the heart
Artery
large blood vessel
carries blood AWAY from the heart
Capillaries
small blood vessel, single layer
connects arteries to veins
site of fluid and gas exchange
Atrioventricular
valves (AV)
separates atria from ventricles
supported by bands of connected tissue
prevents blood from flowing backward
from ventricle to atria
Semilunar Valves
separates ventricles from the arteries
half-mooned shape
prevents blood from entering the
arteries from flowing back into the
ventricles
Atria
thin-walled chambers of the heart
receives de-oxygenated blood from the
veins
Ventricle
muscular, thick-walled chambers of the
heart
delivers oxygenated blood to the
arteries
Septum
wall of muscle that separates right heart
pump from the left heart pump
Aorta
largest artery of the body
carries oxygenated blood away from
the heart
Grade 11 University Biology – Unit 5 Animal Systems
Parts of the Circulatory System
Using your textbook AND the INTERNET, complete the following table about the human circulatory
system
Part
Vein
Artery
Capillaries
Atrioventricular
Valves (AV)
Semilunar Valves
Artia
Ventricle
Septum
Aorta
Structure / Location
Function
Parts of the Heart
For practice and using the diagram below, label the
main parts of the heart
More on the Heart

Pulse is when blood is pushed out of the heart under pressure. At that moment, the arteries stretch
and increase in diameter. This is felt as your pulse. Pulse is measured in BEATS per MINUTE (bpm)
Resting normal pulse (bpm)
Baby
100 - 160
1 – 10 years old
60 – 140
10+
60 - 100
Athlete
40 - 60
Two numbers in blood pressure
 Systole – Blood under pressure LEAVING the heart
 Diastole – Ventricles filling up with blood
Normal Blood Pressure of a healthy adult is 120 / 80
Factors that can change blood pressure
Increase (High Blood Pressure (140 / 90)) – HYPERTENSION

Too much stress

Poor diet (high in fat and cholesterol

Lack of exercise

Weight / obesity
Decrease (Low Blood Pressure ( <90 )) - HYPOTENSION
Sound of the Heart
 First, the atria are relaxed while they fill with blood (DIASTOLE)
 During SYSTOLE, the ventricles contract pushing blood out. This pressure causes the AV valves to
close. This is the LUBB sound
 As the ventricles relax, the SEMI LUNAR VALVES close to prevent the backflow of blood. This is the
DUBB sound.
Heart Beat
 The MYOGENIC MUSCLE surrounds the heart.
 A group of nerves in the heart act as a PACEMAKER. It sets the rhythm.
 Another group of nerves passes an impulse to the ventricles to cause them to contract at the very
same time.
Grade 11 University Biology – Unit 5 Animal Systems
Circulatory System – The Heart
Laboratory – Pulse Rate and Exercise
The heart is a hollow muscular organ about the size of a fist. It contracts at regular intervals to pump blood through
the heart’s chambers and into the AORTA which carries blood to smaller arteries that transport blood throughout the
body. ARTERIES are very elastic vessels that stretch each time the heart pumps blood. CAPILLARIES are tiny
blood vessels connecting arteries to veins. It is in the capillaries that the exchange of nutrients, salts, oxygen and
carbon dioxide occurs between cells and the blood. VEINS carry blood back to the heart. NOTE: the blood does
NOT exert the same pressure on the walls of veins as it does no the arteries.
PULSE RATE is measured by the number of times the heart contracts per minute. What we feel is the expansion
and contraction of an artery as the blood is pushed through it. Most arteries are protected by muscle and they are not
located near the surface. However, some arteries are close enough to the surface to allow you to feel the pulse of
blood through them. Examples include the CARTOID ARTERIES in the side of the neck just below the jaw and the
RADIAL ARTERIES on the inside of the wrist.
AEROBIC RESPIRATION at the cellular level provides energy to the cell, using oxygen and sugar while releasing
carbon dioxide and water along with energy. During exercise, the heart rate and respiration increase allowing the
lungs to bring adequate oxygen to the cells of the body. If the exercise is strenuous or prolonged, energy is provided
by ANAEROBIC RESPIRATION. This process does NOT require oxygen. It provides quick energy, but it also
produces LACTIC ACID that causes muscles to fatigue and cramp. Lactic acid requires oxygen to break down. How
will the circulatory system operate to regain homeostasis in the event of lactic acid buildup?
TASK
You will be

Monitoring your heart rate during various activities

Comparing heart rates after performing different exercises
MATERIALS

Watch with a second hand or stopwatch

Data sheets (attached)
Data Sheet 1
ACTIVIY
Your pulse rate
(beats per minute)
Your partner’s pulse rate
(beats per minute)
Class Average
(beat per minute)
Resting
Standing
Data Sheet 2
Pulse Rate (beats per minute)
ACTIVITY
Resting
Exercise #1
Exercise #2
Person 1
Person 2
Person 3
Your group
average
METHODS
NOTE

If you have asthma or other breathing issues, please modify exercises to by less strenuous. Be your own
monitor.

If you plan to run stairs or step on a chair, you require a “spotter” to watch you will exercising.
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Sit quietly on your stool for two minutes
Determine your resting pulse rate (use a CARTOID ARTERY in your neck) by pressing two fingers against your
artery and counting the number of pulses in 15 seconds and multiplying by 4 (15 X 4 = 60 seconds or one
minute)
Repeat this step
Record your resting pulse rate on Data Sheet #1 and Data Sheet #2
Record your partner’s resting pulse rate on Data Sheet #1
Record your data on the chalkboard and calculate a Class Average
Stand for two minutes BUT remain still
Take your standing pulse rate using the same method
Record this data and your partner’s standing pulse rate on Data Sheet #1 and the chalkboard
Calculate the Class Average Standing Pulse Rate
Design an “Exercise” experiment with two different exercises (e.g., Jumping Jacks for one minute, running up
and down the stairs 2X, running on the spot for three minutes, skipping rope, walking). Your experiment design
MUST include a hypothesis, methods (including materials and appropriate controls) and data collection chart.
Review the experiment with the teacher
Conduct your experiment collecting the data as shown in Data Sheet #2
Prepare a FULL LAB REPORT and answer the questions
Questions
1. From Data Sheet 1, were “Sitting” and “Standing” heart rates the same?
2.
Did your heart rate match the class average?
3.
What was the range of heart rates in the class? Provide two reasons for any difference.
4.
From Data Sheet #2, how did exercise affect heart rate?
5.
Which activity seemed to cause the greatest increase in heart rate?
6.
Why did your body change its heart rate during exercise?
7.
Name two factors other than age that could impact a person’s resting heart rate.
8.
Recalling the heart is a muscle, why do you think regular aerobic exercise is important and smart?
9.
When you exercise, your tissues need more oxygen. This experiment explored one process: the heart.
Yet, the heart is only one part of the overall cardiovascular and pulmonary systems. Recall, red blood cells
pick up oxygen in the lungs and carry it to the muscles. What are other ways your body might increase the
supply of oxygen to the muscles. Provide two ideas.