Transcript 7.8 power point

Circulatory System 7.8
Also known as the cardiovascular system
Consists of the heart, blood vessel, and blood
Transports oxygen and nutrients to body cells
Transports carbon dioxide and metabolic materials
away from body cells
Heart
• Muscular hollow organ often called a pump
• About the size of a closed fist and weighs less
than one pound
• Contracts about 100,000 times each day to
pump the equivalent of 2,000 gallons of blood
through the body
• Located in the mediastinal cavity between the
lungs, behind the sternum, and above the
diaphragm
Heart
• 3 layers of tissue
Endocardium- smooth layer of cells that line the
insides of the heart and is continuous with the
inside of blood vessels
Myocardium- thickest layer, middle muscular layer
Pericardium- Double layered membrane or sac
that covers the outside of the heart. Pericardial
fluid fills space between the two layers and
prevents friction and damage to membranes as
the heart beats or contracts
Septum
• Muscular wall that separates the heart into
a right and left side
• Prevents blood from moving between the
right and left sides
Heart Chambers
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Heart is divided into four parts, or chambers
Two upper chambers are called atria
Two lower chambers are called ventricles
Right atria receives blood as it returns from body cells
Right ventricle receives blood from the right atria and
pushes blood into the pulmonary artery which carries
blood to the lungs for oxygen
• Left atria receives oxygenated blood from the lungs
• Left ventricle receives blood from left atria and pushes
blood into the aorta so it can be carried to body cells
Valves
• One way valves in the chambers of the heart keep blood flowing in
the proper direction
• Tricuspid Valve- located between the right atrium and ventricle.
Closes when ventricle contracts and pushes blood to the lungs
• Pulmonary Valve- located between right ventricle and pulmonary
artery. Closes when right ventricle has finished contracting and
pushing blood into pulmonary artery
• Mitral Valve- located between the left atrium and left ventricle.
Closes when ventricle is contracting and pushing blood into the
aorta. Also called the bicuspid valve
• Aortic Valve- located between left ventricle and aorta. Closes when
ventricle is finished contracting and pushing blood into the aorta
Arrhythmias
• Interference with normal electrical
conduction pattern of the heart
• Causes abnormal heart rhythms
• Can be mild to life threatening
• Life threatening fibrillations are treated
with a AED, a device that shocks the heart
with electrical current. It stops
uncoordinated contractions and allows the
hearts to regain normal conduction pattern
Blood Vessels
• Arteries carry blood away from the heart. The
aorta is the largest artery in the body.
• Receives blood from the left ventricle and
branches into all other arteries.
• First branch of the aorta is the coronary artery
which carries blood to myocardium of the heart
• Arterioles are the smallest branches of arteries
that join with capillaries
• Arteries are more muscular and elastic than
other vessels because they receive blood as it is
pumped from the heart
• Capillaries connect arterioles with venules the
smallest veins
• Located in close proximity to every body cell
• Have thin walls that contain only one layer of
cells
• Allow oxygen and nutrients to pass through the
cells
• At the same time, carbon dioxide and metabolic
products from the cells enter the capillaries
• Veins are blood vessels that carry blood back to the
heart
• Venules are the smallest branches and connect with the
capillaries. Venules join together and become larger to
form veins
• Superior and Inferior Vena Cava are the 2 largest veins.
Superior vena cava brings blood from upper parts of
body, and inferior vena cava brings blood from lower part
of body.
• Veins are thinner than arteries and have less muscle
• Most contain valves to keep blood from flowing
backward
Blood
• Is often called a tissue because it contains many
kinds of cells
• About 4 to 6 quarts of blood in the average adult
(5 liters or about 5000ml)
• Transports oxygen from lungs to body cells,
carbon dioxide from body cells to lungs,
nutrients from digestive tract to cells, metabolic
waste from cells to organs of excretion, heat
produced by body parts, hormones produced by
glands
Plasma
• Fluid part of blood
• About 90% water
• Dissolved substances include, protein
such as fibrinogen and prothrombin
needed for clotting, nutrients such as
vitamins and carbohydrates, electrolytes
such as potassium, calcium, and sodium,
gases like oxygen and carbon dioxide,
metabolic waste, hormones, enzymes
Blood Cells
• Solid elements of blood
• Erythrocytes- red blood cell produced in the red bone marrow at a
rate of about 1 million per minute
• Live about 120 days before being broken down by the liver and
spleen
• 4.5 to 5.5 million rbc’s per cubic millimeter of blood or 25 trillion in
the body
• Mature form is disc shaped and has no nucleus
• Contains a protein called hemoglobin that carries oxygen and
carbon dioxide
• When hemoglobin carries oxygen it gives blood its red color
• If blood contains a lot of oxygen it is bright red, and when there is
less oxygen a darker red
• Leukocytes are white blood cells that are
formed in the bone marrow and live about
three to nine days
• 5000-9000 wbc’s per cubic millimeter of
blood
• Main function is to fight infection
• Phagocytosis- process by which some
leukocytes engulf, ingest, and destroy
pathogens or germs
• 5 types of white blood cells
• Neutrophils- phagocytize bacteria
• Eosinophils- remove toxins and defend body
form allergic reactions by producing
antihistamines
• Basophils- participate in inflammatory response,
produce histamine and heparin
• Monocytes- phagocytize bacteria and foreign
particles
• Lymphoctyes- provide immunity by developing
antibodies
Thrombocytes
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Also called platelets
Usually described as fragments or pieces of cells
Do not have nucleus
Formed in bone marrow and live about 5 to 9 days
Important for clotting process which stops bleeding
When a blood vessel is cut thrombocytes collect at the
site to form clot, secrete serotonin that causes blood
vessel to narrow decreasing the flow of blood, releases
thrombin to form fibrin to form a clot
Diseases
• Anemia- decrease in rbc’s, pale, fatigue, rapid heart rate
• Sickle Cell Anemia- chronic inherited anemia, results in
production of crescent shaped erythrocytes
• Aneurysm- ballooning out or sac like formation on the
wall of an artery, if is ruptures hemorrhage can occur
which can cause death
• Congestive Heart Failure- heart muscles do not beat
adequately to supply blood needs of the body
• Hypertension- high blood pressure
• Myocardial Infarction- Heat attack