Transcript The Circulatory System

The Circulatory System
The circulatory system includes the Heart, Blood Tissue
and the Blood Vessels.
The Circulatory System-Transport
• The absorption and
circulation of materials
throughout an
organism
What does the circulatory system do?
(What is its function?)
1. Delivers nutrients and oxygen to body cells.
2. Carries carbon dioxide and other waste products
away from cells.
 Movement of materials into and out of cells occurs by
diffusion (from an area of high concentration to low
concentration– no energy required)
 Movement also occurs by active transport (from an area of
low concentration to high– this requires energy)
• ** In general, the blood is a fluid tissue
helping to maintain homeostasis for all cells in
the body.
• Transport of needed substances to body cells.
(oxygen, amino acids, glucose, fatty acids,
glycerol, salts, etc.)
The heart functions as a double pump beating in
unison.
1. Deoxygenated blood--relatively low in oxygen
2. Oxygenated blood--relatively high in oxygen
** Heartbeat is stimulated by an electrochemical
impulse.
Pacemaker - in the right atrium - initiates the
heartbeat
3. Transport of wastes from cells. (urea, water,
carbon dioxide in the form of the
bicarbonate ion)
4. Helps to maintain a constant body
temperature.
5. Aids the body in fighting disease.
Blood
Blood = a connective tissue made up of blood cells and a liquid
called blood plasma.
 About 7 % of your body mass
 About 4.5- 5.6 Liters in an adult human
Men = 5.6 Liters
Women = 4.5 Liters
Pregnant woman = 5.0 Liters
The Functions of Blood
Delivers:
Picks Up:
- Nutrients
- waste  kidneys
- Oxygen, Water, minerals
- carbon dioxide  lungs
- Hormones and enzymes
- heat  skin
- pollutants
The Parts of Blood
1. Plasma =carries everything; fluid portion
2. Red Blood Cells =(RBC) gas exchange
3. White blood Cells =(WBC) fight infection
4. Platelets = clotting
Components of Blood
Blood Composition
• Plasma 55% (liquid part of the blood); Blood
Cells 45%
55%
plasma
45 %
RBC, WBC
and platelets
Plasma- nonliving
• Yellow liquid (92% H2O)
• 8 % nutrients, salts, urea, hormones
• Carries:
RBC, WBC, Platelets, Carbon dioxide, food and
waste
BLOOD CELL TYPES
• Red Blood Cells:
– most numerous
– biconcave disc shaped
– smaller than white blood cells, larger than platelets
– no nucleus when mature
– produced in the red marrow of long bones
– destroyed in the liver and spleen
– contain the iron protein compound HEMOGLOBIN
whose chief function is to combine with oxygen and
carry it to the cells
Red Blood Cells- living
• 5 million in 1 drop of blood (most common)
• Shape = donut
Draw here:
• Made in bone marrow
• Live approximately 120-125 days
Hemoglobin = oxygen containing pigment
Binds to oxygen and carries it to the cells
Gives red blood cells its red color
White blood cells- living
• AKA- Lymphocytes or Leukocytes
• White blood cells are larger than red blood cells,
but there are less of them.
• 8000 in one drop of blood
Function of White Blood Cells
 surround and digest bacteria
Attack bacteria and viruses
**Pus = WBC + dead bacteria
YouTube - White Blood Cell Chases Bacteria
White Blood cells
--largest blood cells--several different
types
--about 8,000 per drop of blood
--most are formed in the bone marrow or
in the lymph tissue
--most protect the body against
diseases
by forming antibodies or engulfing bacteria
Main White Blood Cell Types
1. Phagocytes-- engulf bacteria and viruses by
phagocytosis
--able to leave the bloodstream
and move between the cells of
the body by squeezing through
the capillary walls
2. Lymphocytes--produce antibodies which
clump bacterial poisons or bacteria (antigens)
(antigens--foreign substances in the body)
Platelets- living
• Bits of cells
• Live for approximately 10 days
Function of Platelets
creates fibrin = enzyme that helps clot blood
(tiny threads seal cuts)
3. Platelets
--smallest blood cells (fragments)
--150,000 to 300,000 per drop of blood
--needed for clotting
Clotting:
Involves a series of
enzyme controlled
reactions resulting
in the formation of
protein fibers that
trap blood cells and
form a clot.
Pacemaker•Uses electrical impulses from wire
leads inserted into the Heart.
•Keeps the Heart in perfect rhythm.
The Human (Mammalian) Heart
Structure
1. septum: muscular central wall dividing the
mammalian heart into two halves
2. atria: thin walled upper heart chambers
which receive blood pump blood to the
ventricles
3. Ventricles: muscular thick walled chambers
which pump blood from the heart -- the lower
chambers
4. Valves - prevent the backward flow of blood
in the heart
A = aorta
F = left ventricle
B = pulmonary arteries
G = right ventricle
C = pulmonary veins H = valve
D = left atrium
I = vena cavae
E = valve
J = right atrium
Blood Vessels
1. Arteries
--carry blood away from the heart
--usually spurt blood when cut
--all except the pulmonary artery carry
oxygenated blood
--thick walled and elastic
pulse: expansion and contraction of the artery
walls in response to the heartbeat
Veins
--carry blood toward the heart
--contain valves
--closer to the body surface than the arteries
--all except the pulmonary vein carry
deoxygenated blood
--thinner, less muscular and elastic than arteries
--depend upon muscle and diaphragm
movements for blood flow
Capillaries
--most numerous vessels
--connect arteries to veins
--microscopic, one cell thick walls
--site of much exchange between the blood and
the intracellular fluid (lymph) by diffusion
Lymph vessels
-have walls one cell thick
-present around all body cells
-Lymph composition is similar to that of
blood except for the absence of RBC and
some plasma proteins.
-chief site of material exchange with the
tissues
Major lymph vessels have lymph nodes which
contain phagocytic white blood cells which filter
bacteria and dead cells from the lymph.
X = lymph nodes
Valves are present in some lymph vessels--aiding in
the movement of the lymph.
Respiratory movements also aid lymph flow.
Which Way Did it Go?
Blood Pressure
Causes of HBP implicated:
1. excess sodium intake
2. stress
3. cigarettes (nicotine)
4. saturated fats
5. alcohol & caffeine
6. obesity
7. heredity & aging
No cure--may be treated by medication & diet.
"Silent killer"--millions don't know they have it