Transcript Body Systems Circulatory

The Cardiovascular System,
Lymphatic System & Blood
OBJECTIVES:
1. Describe the structure and function of the
human heart.
2. Trace the flow of blood through the heart and
body.
3. Distinguish between arteries, veins, and
capillaries in terms of their structure and
function.
4. Distinguish between pulmonary circulation
and systemic circulation.
5. Summarize functions of the lymphatic system.
♥ Your heart is about the same size as your fist.
♥ An average adult body contains about five
quarts of blood.
♥ All the blood vessels in the body joined end to
end would stretch 62,000 miles or two and a half
times around the earth.
♥ The heart circulates the body's blood supply
about 1,000 times each day.
♥ The heart pumps the equivalent of 5,000 to
6,000 quarts of blood each day.
The Heart
♥ The Heart is cone-shaped
♥ About the size of a fist
♥ Located in the Thoracic Cavity between
the Lungs directly behind the Sternum
(Breastbone).
♥ Tilted so that the APEX (the pointed end)
is oriented to the left.
♥ Locate the heart using a stethoscope
Structure of the Heart
♥ The heart is enclosed in a protective
membrane sac called the PERICARDIUM
♥ surrounds the heart and secretes a fluid that
reduces friction as the heart beats
Pericardium
Structure of the Heart
♥ Our Heart has FOUR CHAMBERS:
♥ UPPER CHAMBERS of the heart are the RIGHT
AND LEFT ATRIA (ATRIUM),
♥ RECEIVE BLOOD COMING INTO THE HEART.
♥ LOWER CHAMBERS are the RIGHT AND
LEFT VENTRICLES
♥ PUMP BLOOD OUT OF THE HEART. The Left
Ventricle is the thickest chamber of the heart because
it has to do most of the work to pump blood to all
parts of the body.
How the Heart Works
RIGHT SIDE
• Pumps flood from the
BODY INTO THE
LUNGS, WHERE
OXYGEN POOR BLOOD
(DEOXYGENATED,
USUALLY SHOWN IN
BLUE) GIVES UP
CARBON DIOXIDE AND
PICKS UP OXYGEN
LEFT SIDE
• Pumps OXYGEN RICH
BLOOD (OXYGENATED,
USUALLY SHOWN IN
RED) FROM THE
LUNGS TO THE REST
OF THE BODY EXCEPT
THE LUNGS.
The Flow of Blood
Right Side
♥ Blood enters right atrium
through the vena cava
(passes through AV
valve)
♥ Passes through tricuspid
valve to right ventricle
♥ Blood transported to
lungs via the pulmonary
artery (through the
pulmonary valve)
Left Side
♥ Blood returns from the
lungs via the pulmonary
vein (passes through AV
valve)
♥ Enters the left atrium,
passes through the
bicuspid valve to the left
ventricle
♥ Left ventricle pumps
blood to the rest of the
body through the aorta
(passes through aortic
valve)
♥ Blood vessels deliver the
blood
Actual Heart
Valves
♥ THE GENERAL PURPOSE OF ALL
VALVES IN THE CIRCULATORY
SYSTEM IS TO PREVENT THE
BACKFLOW OF BLOOD.
♥ They also ensure that BLOOD FLOWS IN
ONLY ONE DIRECTION.
BLOOD VESSELS (ARTERIES,
VEINS AND CAPILLARIES)
♥ The Circulatory System is known as a CLOSED
SYSTEM because the blood is contained within
either the heart or blood vessels at all times.
♥ The blood vessels keep the blood flowing in one
direction.
♥ After the blood leaves the heart, it is pumped
through a network of blood vessels to different
parts of the body.
♥ The Blood Vessels that form this network and are
part of the CIRCULATORY SYSTEM ARE THE
ARTERIES, CAPILLARIES, AND VEINS.
ARTERIES AND ARTERIOLES
(SMALL ARTERIES)
♥ Arteries carry blood from the HEART TO
CAPILLARIES AND THE REST OF THE BODY.
♥ The walls of arteries are generally THICKER
than those of veins.
♥ The smooth muscle cells and elastic fibers that
make up the walls help make arteries tough and
flexible. This enables arteries to withstand the
high pressure of blood as it is pumped from the
heart. The force that blood exerts on the walls of
blood vessels is known as BLOOD PRESSURE.
♥ EXCEPT FOR THE PULMONARY ARTERIES,
ALL ARTERIES CARRY OXYGEN-RICH
BLOOD.
AORTA
♥ The artery that carries Oxygen-Rich blood from
the LEFT VENTRICLE to all parts of the body,
EXCEPT THE LUNGS, is the AORTA.
♥ THE AORTA WITH A DIAMETER OF 2.5 cm, IS
THE LARGEST ARTERY IN THE BODY.
♥ As the Aorta travels away from the heart, it
branches into smaller arteries so that all parts of
the body are supplied.
♥ THE SMALLEST ARTERIES ARE CALLED
ARTERIOLES
CAPILLARIES
♥ ARTERIOLES BRANCH INTO NETWORKS OF
VERY SMALL BLOOD VESSELS CALLED
CAPILLARIES.
♥ IT IS IN THE THIN-WALLED (ONE-CELL IN
THICKNESS) THAT THE REAL WORK OF THE
CIRCULATORY SYSTEM IS DONE.
♥ The walls of the capillaries consist of only one
layer of cells, making it easy for Oxygen and
Nutrients to DIFFUSE FROM THE BLOOD INTO
THE TISSUE.
♥ Forces of diffusion drive CO2 and waste
products from the tissue into the capillaries.
♥ Capillaries are extremely NARROW; Blood cells
moving through them must pass in single file.
VEINS
♥ THE FLOW OF BLOOD MOVES FROM CAPILLARIES
INTO THE VEINS.
♥ Veins form a system that COLLECTS blood from every part
of the body and CARRIES it back to the HEART.
♥ The smallest veins are called VENULES.
♥ LIKE ARTERIES, VEINS ARE LINED WITH SMOOTH
MUSCLE. Vein walls are thinner and less elastic than
arteries. Veins though are more FLEXIBLE and are able to
stretch out readily.
♥ Large veins contain valves that maintain the one direction
flow of blood. This is important where blood must flow
against the force of gravity.
♥ The flow of blood in veins is help by contractions of
skeleton muscles, especially those in the legs and
arms. When muscles contract they squeeze against veins
and help force blood toward the heart.
Normal
Valves
When Valves Fail: Varicose Veins
Patterns of Circulation
• THE PULMONARY CIRCULATION carries blood
between the heart and the lungs
– BEGINS AT THE RIGHT VENTRICLE AND ENDS AT THE LEFT
ATRIUM.
• THE SYSTEMIC CIRCULATION supplies each major
organ with blood including the heart
– STARTS AT THE LEFT VENTRICLE AND ENDS AT THE
ATRIUM, CARRIES BLOOD TO THE REST OF THE BODY.
• The heart receives its supply of blood from a PAIR of
CORONARY ARTERIES leading from the Aorta.
• When things go wrong…
Lymphatic System
• As blood circulates throughout the body, fluid
from the blood LEAKS into tissue.
• A NETWORK OF VESSELS KNOWN AS THE
LYMPHATIC SYSTEM COLLECTS THE FLUID
AND RETURNS IT TO THE CIRCULATORY
SYSTEM.
• The loss fluid is known as LYMPH, a transparent
yellowish fluid, and is collected in lymphatic
capillaries and moves to larger lymph vessels.
Lymphatic System cont…
• The lymphatic system has no pump like the
heart, lymph must be moved through vessels by
the squeezing of skeletal muscles.
• Lymph vessels pass through small bean-shaped
enlargements (organs) called LYMPH NODES,
which act as filters and produce special white
blood cells called LYMPHOCYTES that are
specialized to fight infection.
• The fluid is returned to the circulatory system at
an opening in a vein located under the left
clavicle, or collarbone, just below the shoulder
Blood
The fluid component of the
cardiovascular system
(liquid connective tissue)
Objectives
1. List the components of blood.
2. Distinguish between red blood cells,
white blood cells, and platelets in terms
of their structure and function.
3. Summarize the process of blood
clotting.
4. Explain what determine the compatibility
of blood types for transfusion.
Major functions of blood
• Transportation of dissolved gasses,
nutrients, hormones and metabolic wastes
• Regulation of the pH and ion composition
of interstitial fluids
• Restriction of fluid loss at injury sites
• Defense against toxins and pathogens
• Stabilization of body temperature
Plasma
• Approximately 55 percent of blood in
made up of a fluid portion called PLASMA.
• Plasma is the straw-colored liquid portion
of blood and is 90% water and 10 percent
dissolved fats, salts, sugars, and proteins
called PLASMA PROTEINS.
Other Components of Blood
• THE CELLULAR PORTION OF BLOOD MAKE
UP THE OTHER 45 % & INCLUDES SEVERAL
TYPES OF HIGHLY SPECIALIZED CELLS AND
CELL FRAGMENTS
• THEY ARE RED BLOOD CELLS (RBC), WHITE
BLOOD CELLS (WBC), AND PLATELETS.
• Hematocrit – percentage of whole blood volume
contributed by formed elements
Formed Elements
b. UAA, AAG
Red Blood Cells (erythrocytes)
• RBC are the most numerous.
• One microliter of blood contains approx. 5 million
RBCs.
• RBC are BICONCAVE, or shaped so that they are
narrower in the center than along the edges.
• RBC are produced from cells in the Bone Marrow, they
are gradually filled with HEMOGLOBIN which forces
out the nucleus and other organelles.
• Mature RBC do not have a Cell Nucleus and
Organelles. The Mature RBC becomes little more
than a membrane sac containing Hemoglobin.
RBC Structure
Hemoglobin
• Binds and transports oxygen and CO2
• Each RBC contains about 280 million
hemoglobin molecules
• Each RBC can potentially carry more than a
billion oxygen molecules at a time.
Hemoglobin Structure
Hemoglobin is the iron-containing protein that
gives RBC the ability to carry
oxygen. Hemoglobin gives the RBC their color.
RBC origin and production
• Red blood cells are formed in the bone marrow
(erythropoiesis) and released into the bloodstream
• RBC stay in circulation for about 120 days
before they are destroyed by special WBC in
the liver and spleen.
• RBC in your body are dying and being replace
at a rate of about 2 million per second.
• Blood doping – athletes inject RBCs that were
removed at an earlier date more
oxygen to muscles
White Blood Cells (leukocytes)
• WBCs defend body against invasion by pathogens /
they remove toxins, wastes, and abnormal or
damaged cells
• WBCs have nuclei and other organelles but lack
hemoglobin and are much bigger than RBCs
• Outnumbered by RBC almost 500 to 1.
• WBC are produced in the Red Bone Marrow, The
Lymph Nodes, and the Spleen.
• They are larger than RBC, almost Colorless, and do
NOT Contain Hemoglobin.
• WBC have a nucleus and can live for many months or
years.
WBC
• THE MAIN FUNCTION OF WBC IS TO
PROTECT THE BODY AGAINST INVASION BY
FOREIGN CELLS OR SUBSTANCES.
• WBC called PHAGOCYTES can destroy bacteria and
foreign cells by phagocytosis (engulfed and digested)
• Some produce special proteins called ANTIBODIES,
and some release special chemicals that help the body
fight off disease and resist infection.
• Doctors are able to detect the presence of infection by
counting the number of WBC in the blood. When a
person has an infection, the number of WBC can
Double.
Platelets (thrombocytes)
• Platelets are NOT Cells; they are tiny
fragments of other cells that were formed in the
bone marrow.
• Platelets are small membrane bound cell
fragments that contain enzymes and other
substances important to the process of clotting
• Form a “platelet plug” (patch in blood vessel)
that combines with plasma proteins to form
blood clots
• Lifespan of only 7-10 days, then recycled by the
spleen
Platelet origin and production
• Platelets are made in the bone marrow,
then enter the bloodstream
• The rate of platelet production is
stimulated by a peptide hormone (TPO)
Blood Smear
RBC
platelet
WBC
When you turn 18,