Download 1A- Circulation

Biology
Topic One: Circulation
Functions of the Circulatory System
•  Transportation:
–  nutrients to cells and wastes away from
cells
–  chemical messengers from cells in one
part of the body to distant target tissues
•  Distributes heat throughout the body
•  Along with the kidneys, maintains
acceptable levels of body fluid.
•  Defense against invading organisms
A. Heart
Your heart is located where?
A) On the left side of your chest
B) In the middle of your chest
C) On the right side of your chest
During a medical checkup,
the doctor listens on the left
side with a stethoscope
because the heart is
pointed slightly to the left,
and sounds produced by
parts of the heart are easier
to hear there.
1
Anatomy of the Heart
•  General Structure
–  The size of your fist
–  Located in the centre of your chest
–  Made of cardiac muscle
–  Composed of two pumps
Heart Structure
Part
• Septum
Structure
Functions
Muscular wall
Divides heart in half
• Right
Small thin
walled
Collects
DEOXYGENATED
blood from body
• Left
Small thin
walled
Collects
OXYGENATED
blood from lungs
Atria
Pumps blood to entire body
2
Heart Structure
Ventricles
• Right
Large and thick
walled
Collects
DEOXYGENATED blood
from right atria and
pumps to the lungs
• Left
Large and thick
walled
Collects
OXYGENATED blood
from the left atria and
pumps it to the body
Coronary Vessels
•  Heart muscle needs
a constant supply of
oxygen
•  Blood vessels that
supply the heart
with oxygen rich
blood are called
coronary vessels
•  If these vessels are
blocked a heart
attack may occur
Heart Valves
• Describe the function of heart valves:
– Prevent backflow of blood in the heart
– Ensure blood is pumped in the right direction
Type
Structure
Function
Atrioventricular • Between Atria and • Direct blood flow
Ventricle
into the ventricles to
• Flaps of tissue
maximize pump
volume
Semi Lunar
• Found at base of
arteries leaving
ventricles
• Half moon cups of
tissue
• Open = Ventricles
contracted
• Closed = ventricles
relaxed
3
Blood Vessels
Blood Vessel
Function
Superior vena
cava
• Returns blood from heart and upper body
• Deoxygenated
Inferior vena
cava
• Returns blood from lower body
• Deoxygenated
Pulmonary artery • Carries blood from heart to lungs (exiting
from right ventricle)
• Deoxygenated
Pulmonary veins • Carries blood from lungs to left atrium
• Oxygenated
Aorta
• Carries blood from left ventricle to body
• Oxygenated
Not enough room to label?
Just write the number in the
box beside the correct
structure
4
Heart Summary
Label the Heart
•  Label the diagram in your notes.
•  Try first using your memory and next
using page 11 to check your answers
Blood flow through the heart
AV Valve
Right Side of the Heart
The blood first enters the right atrium of the heart
from the body through two blood vessels Inferior
Vena Cava, & Superior Vena Cava.
The Superior VC returns blood from the head and
upper parts of the body.
The Inferior VC returns blood from the lower parts.
This blood has been to the tissues and is LOW in
oxygen and HIGH in carbon dioxide.
AV Valve
From the right atrium blood goes through the
atrioventricular valve into the right ventricle
Then the right ventricle contracts, forcing blood
through the Pulmonary Semilunar Valve into the
pulmonary artery.
5
Blood flow through the heart
Pulmonary Circulation
AV Valve
The pulmonary artery branches to
carry the blood to both lungs.
In the lungs, the blood becomes
oxygenated, picking up oxygen
and releasing carbon dioxide.
AV Valve
The blood passes through the
lungs and into the pulmonary
veins.
Blood flow through the heart
AV Valve
Left Side of the Heart
These four veins return blood to
the heart, into the left atrium
From the left atrium, the blood
passes through the left AV valve
and into the left ventricle
AV Valve
Finally, blood passes through the
aortic semilunar valve into the
aorta and goes to all parts of the
body .
Cardiac Cycle / Heart Beat
6
Heartbeat
Heart beat has two phases
•  Systole
–  Ventricles contract and eject blood from
the chambers
•  Diastole
–  A chamber of the heart (either atria or
ventricle) relaxes and fills with blood
Heart Sounds
The lub :
•  AV valves
closing
•  ventricles
contract forcing
blood out of the
semilunar
valves.
•  High ventricular
pressure
Heart Sounds
The dub :
•  Semilunar valves
close
•  atria and
ventricles relax
and fill with
blood (diastole)
•  Low ventricular
pressure
7
Amount of blood pumped depends
on two factors
Definition
Stroke
volume
volume of blood pumped by the
right/left ventricle of the heart in
one contraction
Heart rate The number of heart beats per unit
time (beats per minute)
Factors Affecting Heart Rate
•  Internal Pace Maker
–  Cardiac muscle cells contract with
no external nerve stimulus.
–  This type of muscle is called
myogenic muscle
–  When in contact with each other
these muscles contract in unison
–  The beat is set by the sinoatrial, or
SA node
–  Located where the vena cava enter
the right atrium
–  Often called the pacemaker
8
Exercise (page 15)
•  Define Cardiovascular training and
describe the positive effects it has on
the heart
–  Exercise that improves your hearts
ability to provide working muscles with
oxygen
–  Cause the heart to increase in elasticity
thereby increasing the volume of blood
it pumps every minute
–  Heart needs to beat less to be as
efficient
Target Heart Rate (age 17)
My Target Heart Rate =
Personal Health Goal
203
Percent of
Maximum
Heart Rate
beats/minute
My Target Heart Rate
Maintain Fitness Level
50 to 60%
101 - 121
Increase fat burning or
weight loss
60 to 70%
121 - 142
Increase cardiovascular
endurance
70 to 80%
142 - 162
B. Blood Vessels
• Three types of blood vessels transport blood
Vessel
Artery
Vein
Structure
Function
Thick walled vessels,
small diameter
Small arteries called
arterioles
Carry blood AWAY
from heart
Thin walled, large diameter,
have valves
Small veins called venules
Carry blood
TOWARD heart
Capillary Microscopic tube 1 cell thick Exchange nutrients
with cells
9
Arteries and Arterioles
• 
• 
• 
Arteries can be defined as the blood
vessels that carry blood away from
the heart.
They have thick, elastic, muscular
walls. This elastic tissue allows
them to stretch when the heart
contracts. This stretching of the
arteries can be felt as the pulse.
Blood from the arteries passes into
smaller arteries, called arterioles.
Arteries and Arterioles
Capillaries
10
Capillary Material Exchange
•  Arteries and veins are important for
carrying blood through our bodies.
•  However all the vital relationships between
the blood and the tissues occur through
the capillaries.
•  Dissolved foods and oxygen pass from the
blood through the thin walls of the
capillaries into the tissues.
•  At the same time waste products and
carbon dioxide move from the tissue cells
into the blood.
•  Movement of the material into and out of
the capillaries is accomplished by
diffusion and osmosis
Veins and Venules
• 
• 
• 
Blood flows from the capillaries to small
veins called venules. The venules come
together and eventually form veins.
The function of veins is to carry blood
towards the heart. The pressure that
forces blood through the arteries does
not continue on through the capillaries
and into the veins. As a result veins do
not have to be as strong as the arteries
and have walls that are much thinner and
less muscular than those of arteries.
Also with less muscle in the walls, the
internal diameter of a vein is greater than
an artery.
Veins and Venules
•  The return of blood to the
heart by the veins involves
two problems. The blood
flows smoothly in the veins
under low pressure. Also
blood flow is often upward
against gravity. To solve
these problems the body has
evolved two mechanisms.
–  Firstly veins contain a series of
one way valves
–  Secondly the contraction of
skeletal muscle, squeezes the
veins, increases the pressure
and forces blood to flow towards
the heart.
11
Comparing Blood Vessels
12.
a. The pulmonary arteries carry oxygenpoor blood from the heart to the lungs.
b. The aorta is the body s largest artery.
c. The coronary arteries carry oxygen-rich
blood from the aorta to nourish the heart
tissues.
d. The pulmonary veins carry oxygen-rich
blood from the lungs to the heart.
e. The vena cava carry oxygen-poor blood
from the body s tissues to the heart.
13. Arteries always carry blood away from
the heart and veins always carry blood
to the heart. This is always true.
However, it is not always true that
arteries carry oxygen-rich blood and
veins carry oxygen-poor blood.
•  The pulmonary arteries carry oxygenpoor blood from the right ventricle to the
lungs. The pulmonary veins carry
oxygen-rich blood from the lungs back to
the heart.
12
14. It is important for the walls of
capillaries to be thin so that oxygen and
other substances needed by cells can
diffuse from the blood to the tissue cells.
The thin walls also allow carbon dioxide
and waste materials to diffuse from the
tissue cells into the blood.
Comparison of Blood vessels
Blood Pressure
•  Blood pressure is the measure of the
pressure in the blood vessels when
the heart contracts (systolic
pressure) and when the heart relaxes
(diastolic pressure).
•  In humans the blood pressure is
taken in the upper arm using a
sphygmomanometer
•  Each BP reading is given systolic
over diastolic
•  Example: the average person s BP is
around 120/80 mm Hg
13
Blood Pressure
•  The normal range of BP for adults is:
–  Systolic: between 90 and 135 mmHg
–  Diastolic: between 50 and 90 mmHg
–  Blood pressure over 140/90 is considered high
or hypertension
•  Adam s BP
Blood Pressure
Factors Affecting Blood Pressure
• 
• 
• 
Many factors can affect a person s blood
pressure. Stress, salty food, exercise are
a few of the factors that increase blood
pressure. Low blood pressure can be the
result of injury, shock or low body fluid.
All changes in blood pressure can be the
result of a change in one or more of the
following parts of the circulatory system
that control blood pressure:
Heart: Heart Rate and Contraction Force
14
•  Blood Vessels: Diameter and
Elasticity of Blood Vessel Walls
•  Blood Vessel: Elasticity
•  Blood: Amount of Blood
15
C. Blood
Function of the Blood
• 
• 
• 
• 
Deliver nutrients and
remove waste
Transport chemical
messengers,
vitamins and
minerals
Fight disease
Maintain water
balance, temperature
and pH
Components of Blood
16
Red Blood Cells
Characteristic
Details
Erythrocytes
Another name for red blood cells, most numerous blood cell
Function
Carry oxygen to the tissues using the molecule Hemoglobin
Hemoglobin
Causes red color of blood, Complex protein containing iron
Combines with oxygen in the lungs (turns red – oxygenated oxyhemoglobin)
Releases oxygen at tissue (turns dark red – deoxygenated)
Structure
Biconcave (cream filled donut shape) increases surface area for
gas exchange
Lifecycle
Made by red bone marrow, only last about 120 days in blood
stream
No nucleus at maturity (more room for hemoglobin)
RBCs
Label the following diagram
17
White Blood Cells
Characteristic
Details
Leukocytes • Another name for white blood cells,
much lower numbers in blood
Function
• Fight disease and foreign invaders
Structure
• Much larger than red blood cells
• Irregular shape
• No pigment (slides of blood cells need to
be stained to see them)
Lifecycle
• Made by bone marrow, last about 13 – 20
days in the blood stream
• Have a nucleus at maturity
Platelets
Characteristic
Details
Function
• Trigger a series of reactions to clot blood
• Few in number, formed in red bone marrow
Structure
• Much smaller than red blood cells
• Irregular shape, No pigment
• Membrane bound and filled with
thromboplastin
Clotting
Process
1.  Skin is cut and blood leaks out
2.  Platelets come into contact with the rough
surface of the cut and rupture to release
chemicals that convert the protein
fibrinogen into fibrin
3.  red blood cells get caught in the fibrin net
to from a blood clot
4.  The clot hardens into a scab
Plasma
• 
• 
Plasma is a yellowish liquid
containing 92% water
Plasma holds and transports the
following substances:
– 
– 
– 
– 
– 
Blood cells
Dissolved waste carbon dioxide
Hormones from glands
Digested nutrients such as glucose
Proteins involved in blood clotting
(fibrinogen)
–  Proteins involved in immunity
(antibodies)
18
Answer the following questions
• 
Refer to figure A1.11. Identify the blood
component that corresponds best to each
of the bags I, II and II
• 
Burn victims suffer a significant loss of
skin tissue and are, therefore, highly
susceptible to deadly dehydration. What
blood component best addresses this
problem?
Answer the following questions
•  A cancer patient receiving radiation
treatment is often unable to produce
enough of a key component that prevents
uncontrollable internal bleeding. Identify
the blood component given to this patient
in a transfusion.
•  Explain the following statement:
Every time you give blood you can save up
to three lives
Disorders of the blood
Disorder
Blood
Cells
involved
Symptoms
Description
High
Altitude
The body adapts to low
atmospheric oxygen at high
altitudes by producing more
red blood cells.
Anemia
Low iron levels in the diet may
result in fewer than normal red
blood cells. Individuals with
anemia lack energy due to less
oxygen being transported to
the tissues for cellular
respiration.
19
Blood Disorders
Hemophilia
Hemophilia or bleeder s disease is a genetic
disorder of the blood. Anyone who
biologically has trouble forming blood clots or
bruises easily is considered to have
hemophilia. These people do not produce a
substance in the blood that is needed for the
normal clotting. This is because the gene that
controls the production of this factor is
defective.
People with Hemophilia A bleed severely and
may even die from loss of blood as a result of
wounds that would be of slight importance to a
normal person. Transfusions of blood or the
missing clotting factor help temporarily with
this condition.
Leukemia
Leukemia is cancer of the white blood cells.
Like other cancers, leukemia is associated with
rapid and uncontrolled cell production. The
numbers of the leukocytes in the blood
increases but the cells do not function
normally. Individuals with leukemia are prone
to infection and other disorders.
D. Cardiovascular diseases
•  Define cardiovascular disease:
–  Diseases that affect the heart or blood
vessels
20
Cardiovascular disease and cholesterol
• 
Define cholesterol:
–  Waxy, fat like
substance found in
cell membranes of
animals
• 
Describe the vital
role of cholesterol:
–  Production of
hormones and
vitamin D
–  keep membrane
fluid
21
Cardiovascular disease and cholesterol
•  Describe what is
meant by plaque:
–  Semi-hardened
accumulation of
stuff floating in
plasma
•  Result of plaque
accumulation:
–  Narrowing arteries
–  Causes stiffening =
increase BP and
potential blockage
Types of lipoproteins:
•  Low-density lipoprotein: Bad
cholesterol LDL
–  carries cholesterol from the liver to the
body, too much causes deposits on the
arterial walls
•  High-density lipoprotein: Good
cholesterol HDL
–  Carries cholesterol from the body to the
liver
–  Too much = less likely for deposits to
form on arterial walls
Heart Healthy Lifestyle
• 
Individuals at greatest risk of
cardiovascular Disease:
–  Male over 65 with a family history
• 
Negative Cholesterol Lifestyle
Choices:
–  Eat foods high in cholesterol,
sedentarily life style, stress, alcohol,
fat
• 
Positive Cholesterol Lifestyle
Choices:
–  Exercise, right food choices, relax!
22