The Circulatory System
Part 2
Blood, Lymph and ETC
Composition of
Blood

a.
b.
Blood will
separate into
two parts:
55% plasma
(liquid)
45% blood
cells (solid)
(called Formed
elements)
Mostly water (92%) with
MANY different dissolved
substances:
a.
Nutrients – glucose, amino
acids, vitamins, minerals
b.
CO2,O2
c.
Blood proteins:
i. Antibodies
ii. hormones
iii. clot-forming proteins.
(fibrinogen)
iv. Albumin (transports
bilirubin)
v. Globulins (the protein in
lipoproteins)
d. Salts: Na+, Ca+, K+, Mg+
e. wastes: urea

list the major
components of
plasma

i.
Antibodies -part of the immune system
- help fight infections.
Foreigner
 antibodies 
- tag the foreigners for
the killer cells

Killer
Cells
ii.
Hormones

Chemical
messengers
sent from
brain to tell
cells or
organs what
to do; travel
via blood
iii. Clot-Forming ProteinsFibrinogen

Work with platelets to
form a thrombus (scab)
describe the
shape, function,
and origin of red
blood cells, white
blood cells, and
platelets



A. Red Blood Cells
B. White Blood Cells
C. Platelets
Red Blood Cells





Aka. Erythrocytes
Source = stem cell
Disc-shaped
Hemoglobin has iron
in it (makes your
blood red!)
Delivers gases to and
from cells
White Blood Cells




Aka. Leukocyte
Source = stem cells
Larger than RBC
Work together with
antibodies to fight
infections
Platelets




Aka. Thrombocyte
Source = stem cell
Fragment of larger cells
Clots blood(scab)
Blood Clot
Blood Cell Formation Diagram
Review


Plasma: Water,
nutrients, CO2,
antibodies,
hormones, clotforming proteins
Blood Cells: RBC’s,
WBC’s and Platelets
describe capillary-tissue fluid
exchange
Determined by two
forces:
1. Blood Pressure
2. Osmotic Pressure
(the pressure that
water feels to move
according to the
concentration
gradient between
the tissues and the
osmotic vs hydrostatic pressure animation
blood





At the arteriole end
of the capillary:
B.P.
= 40mmHg
O.P.
= 25mmHg
Net
= 15mmHg
Moving through
the Capillary


Since BP exceeds OP,
water, aa’s, and
oxygen leave the
capillary because
they are forced
(squeezed) out of the
blood and into the
cells.
Blood cells and
proteins are too large
– they stay in the
blood



BP
OP
Net
= 25mmHgMiddle
= 25mmHg
= 0 mmHg
of Capillary


BP and OP are
about equal in the
middle of the
capillary so
diffusion causes
the nutrients to
leave the blood
and enter the cells
(following their
concentration
gradient)
Wastes will diffuse
out of the cells and
into the blood at
this point as well.
Venule End of the Capillary



BP = 10mmHg
OP = 25mmHg
Net= 15mmHg (in
the opposite
direction!)


Now OP is greater than BP, so
water will move from the
tissues and into the blood.
Urea and carbon dioxide are
also carried with the water
Lymph System
Lymphatic System
3 main functions:
1.
2.
3.
transport of excess tissue fluid
back to cardiovascular system
absorption of fat from the
intestine and transport to blood
fighting infection by distributing
germ-fighting white blood cells=
lymphocytes
identify and give functions of
lymph capillaries, veins, and
nodes

considered part of the circulatory
system since it contains lymph, a
moving fluid that comes from the blood
and returns to the blood by way of the
lymphatic vessels.

The lymphatic system is thus a secondary
transport system. Lymph has no pump
of its own. Its flow depends on pressure
from the blood system, the massaging
effect of the muscles and the one-wayvalves in it’s vessels.


More water is
forced out of the
capillary at the
arteriole end then
re-enters at the
venule end.
The LYMPHATIC
system vessels
collect the extra
water and return it
to the blood at the
duct connected to
the subclavian vein
1. Excess fluid

interstitial fluid, the lymph
picks up particles too big
to be absorbed through
capillary, include: cell
debris, fat globules, and
tiny protein particles
 lymph is filtered by the
numerous white blood
cells
 fluid re-enters the blood
through the subclavian
vein.

2. Absorbs
Fat
3. Fighting Infection
 The
lymphatic system also
distributes germ-fighting white
blood cells.
 Lymph resembles plasma
 It is formed from bits of blood and
other body liquids, called
interstitial fluid that collect in the
spaces between cells.
Lymph Organs

Lymph nodes – round
structures located along
lymph vessels (beneath
armpits, base of jaw,
groin )



Filters lymph
Produce lymphocytes
(WBC) which produce
antibodies
Other lymph organs include
tonsils, spleen, thymus
gland
Blood and Body Temperature


Your blood vessels help
control your body
temperature by
sending extra blood to
your skin if you are hot
OR by keeping extra
blood AWAY from your
skin to keep you warm
The capillaries DILATE
or CONTRACT to
control the blood flow
Open heart surgery
Regulation of Blood Pressure
occurs by Four Mechanisms:
1. Altering Heart Rate
2. Altering Contactility (how
hard it pumps)
3. Altering Blood Vessel
Diameter
(vasoconstriction or
vasodilatation)
4. Altering Blood Volume
(kidneys either re-absorb
extra H2O or expel extra
H2O)
The Cardiovascular Centre in the Brain (a group of
neurons scattered within the medulla)
 - will regulate the heart rate using all of these
mechanisms to varying degrees causing either an
increase or decrease in BP.
Hypertension = high blood pressure (over 120/80)
Hypotension = low blood pressure (under 120/80)

Keeping your Circulatory
System Healthy




Eat a healthy diet
(try to keep the
saturated fats and
cholesterol, and
salt levels low)
Get lots of sleep
and exercise
Don’t smoke
Drink lots of
water




Average resting heart rate
is 60-80 beats per minute
(bpm)
The heart is a muscle –
exercise makes it stronger
A highly conditioned
aerobic athlete (ex. Long
distance runner) will have
a resting heart rate of 2840 bpm.
When exercising, a good
target range for heart rate
in teens is between 150190 bpm
Heart Rate
High Blood
Pressure





BP is higher than normal all of
the time
Puts extra strain on the heart
Can cause capillaries to burst
damaging heart, brain or
kidney tissue
Is the leading cause of heart
failure
Too much salt in the diet can
cause HBP, as can excessive,
long term stress
Some Factors that can affect
BP:




Exercise: raises BP during exercise, but decreases BP
after because the heart is stronger.
Sodium intake: Increases Blood Volume which
increases BP
Ca++ and K+ intake: Decreases BP
Alcohol Consumption: Increases BP because in
increases the acidity of the blood, which stimulates the
CV centre to increase BP
Some more Factors that can
affect BP:





Body Weight: Being overweight puts extra
strain on the heart: increases BP
Smoking: increases BP
Stress: The autonomic NS thinks that you
must prepare for a fight, therefore
increasing the BP
Atherosclerosis: Decreases the diameter
of vessels - therefore increasing BP
ETC.!!

The CV centre receives
sensory input from many
different sources:
1. Higher brain centers
(telling you to prepare for
something)
2. Baroreceptors monitoring blood pressure
by using stretch receptors
in the blood vessels
3. Chemoreceptors monitoring O2 , CO2, and
H+ concentrations in the
blood
Cardiovascular
Centre