Download Blood and Vessels

THE MAMMALIAN
CIRCULATORY SYSTEM
SBI3C
Main Parts of the System
 Heart (the pump)
 Vessels (tubes)
 Blood (transport fluid)
An Efficient System
 Blood travels within vessels
at all times
 Efficient transport of
materials to and from cells
of body
 3 circulatory pathways
- systemic pathway
(to & from body’s organs)
- pulmonary pathway
(to & from lungs)
- cardiac pathway
(to & from heart muscle)
General Functions
 Transport
- oxygen to body cells
- carbon dioxide to
lungs
- nutrients to body
cells (sugars, amino
acids, vitamins, etc)
- hormones (e.g. insulin)
- wastes to kidneys (urea)
 Defense against foreign
invaders (e.g. bacteria,
viruses)
 Repair to blood vessels
(clotting)
 Body temperature
regulation
 Maintenance of water
levels in body
The Blood
 The red, opaque whole
blood of mammals
consists of 4
components –
Red blood cells
White blood cells
Platelets
Plasma
Blood Parts
• Whole blood can be
separated into 3 layers by
centrifugation (spinning it at
high speeds)
Red Blood Cells
 also called RBC’s or
erythrocytes
 Biconcave shape
 Lack a nucleus
 Iron-containing, red
protein, hemoglobin
 Carry the majority of
oxygen as oxyhemoglobin
to cells from lungs
 Carry the majority of
carbon dioxide as
bicarbonate ions (HCO3-)
from cells to lungs
White Blood Cells
 Also called WBC’s or
leucocytes
 WBC’s defend body
against bacteria & viruses
 Macrophages, produced in
bone marrow, destroy by
phagocytosis
 Lymphocytes, produced in
lymph tissue (glands,
tonsils, adenoids), destroy
by producing antibodies
and toxic chemicals
Platelets
 Also called
thrombocytes
 Gather at site of
damaged blood cells
 React with plasma
factors to form a
temporary clot
(thrombus) to stop
leakage of blood from
vessel
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A clear, straw-coloured liquid
91% water
55% of blood
Transports
- some O2 and CO2
- nutrients and wastes
- hormones
- clotting factors
- blood cells and platelets
- water balance chemicals
- heat to keep body warm
& cool
Plasma
The Blood Vessels
 Blood vessels create a
continuous pathway to and
from heart
 3 main types of blood
vessels
- arteries
- veins
- capillaries
 All arteries carry blood
away from heart
 All veins carry blood
towards the heart
 Capillaries connect arteries
to veins
Comparing Circulatory Pathways
 Mammalian system uses a double pump (heart) and keeps
oxygenated blood separate from deoxygenated blood
Arteries
 Large, muscular thick-walled
vessels with a small inner
diameter
 Carry mainly oxygenated
blood under high pressure
from heart to body*
 *Exception – pulmonary
arteries deliver deO2 blood
from heart to lungs
 Disorder – aneurysm
Veins
 Large, thin-walled vessels
with a large inner diameter
 Contain one-way valves
 Carry mainly
deoxygenated blood under
low pressure from body to
heart*
 Skeletal muscle
contractions return blood
to heart
 *Exception – pulmonary
veins return O2 blood from
lungs to heart
 Disorder – varicose veins
Major Arteries & Veins
 Associated with heart,
lungs and abdominal
cavity
renal artery
renal vein
Capillaries
 Microscopic, one-cell
thick vessels
 Inner diameter less than 7
m
 Carry blood cells under
low pressure in single file
for O2-CO2 exchange and
nutrient-waste exchange
 Plasma and WBC’s able to
squeeze out of capillaries
at organs
The End