The Human Circulatory System and the Components of Blood
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Transcript The Human Circulatory System and the Components of Blood
The Human Circulatory System
and the Components of Blood
Circulatory System
The circulatory system is also
referred to as the cardiovascular
system
Functions very closely with digestive
and respiratory systems
Basic system requires:
1. a pump (heart);
2. vessels/pathways (veins, arteries,
capillaries);
3. fluid (blood).
Circulatory System
Key Roles:
Maintains homeostasis
body temperature regulation
controls blood pressure
Delivers and removes substances
throughout body
Delivers
-
-
nutrients
oxygen
messages (via hormones)
toxins
Removes
-
-
metabolic wastes
carbon dioxide
toxins
Components of Blood
a sample of blood can be spun in a
centrifuge
high speed, circular motion
causes blood to separate by the weights
of its components
Components of Blood
Erythrocytes: Red Blood Cells
Produced in bone marrow, stored in spleen
Constantly destroyed and replaced
Distinct biconcave shape
Flattened disc that is pinched in the centre
Makes it flexible for traveling through various
blood vessels
No nucleus
No mitochondria
Contains special
hemoglobin molecule
Hemoglobin
Complex protein made up of 4 protein
chains, each with a central iron-containing
heme group
Iron gives RBCs their distinct red colour
Iron binds with oxygen
(4 O2 molecules per
hemoglobin
molecule) – blood
becomes
oxygenated
Iron is recycled in
bone marrow
Anemia
Medical condition when there is a less
than normal amount of hemoglobin
in the blood
Less hemoglobin, less O2 being
delivered throughout the body
Can be caused by a genetic disorder
(e.g., sickle cell anemia or
thalassemias) or by a great loss of
blood
Leucocytes: White Blood Cells
Produced in bone marrow
Larger than red blood cells, but much
fewer in number
Amoeboid-shaped
Contain nucleus and lysosomes
Leucocytes: White Blood Cells
Part of body’s immune response system
Detects and defends body from infection
and diseases
Pus is formed at site of infection
Lysosomes digest foreign bacteria
White blood cells (living & dead) + bacteria
Body’s natural “soap”
An increase in WBCs indicate the body is
fighting an infection
A problem with WBC overproduction could
mean Leukemia
Platelets
Fragments of special cells from the
bone marrow
Important for circulatory system
repair
Form blood clots
Platelets – Blood Clotting
Detect damaged blood vessels
Burst and release special adhesive
chemicals
Platelets stick together and form
a platelet plug
Through chemical reactions,
forms strand-like fibrin molecule
A mesh of fibrin strands forms a
blood clot
Clot protects body from losing
blood through the damaged vessel
Holds vessel wound together until it can be
reconstructed with new tissue growth
Hemophilia
X-linked genetic disorder
Individual lacks special proteins that
are needed for creating blood clots
Can bruise easily
Can bleed excessively if cut –
sometimes bleeding to death
Shock
An actual medical condition – can be lifethreatening
Body (or parts of body) shut down because
circulatory system cannot meet oxygen
demands of some vital organs
Body reduces blood flow to arms and legs so it
can maximize O2 getting to the vital organs (in
body’s core)
Can result from loss of blood, extreme fright or
emotional disturbance
First Aid:
Put person in half upright position, keep warm
Apply direct pressure to any areas of severe
bleeding
Get (call for) medical help