is2 circulation ppt
TRANSCRIPT
![Page 1: IS2 Circulation PPT](https://reader036.vdocuments.mx/reader036/viewer/2022062307/555038abb4c9058f2f8b546d/html5/thumbnails/1.jpg)
Why do we need a transport system?
IS2
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Functions
• Transport nutrients, hormones and oxygen throughout the body
• Carry waste away from cells (ex. CO2, urea)• Protect body from infection (it transports
antibodies and white blood cells)
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Parts of Cardiovascular System
• Heart• Blood• Blood Vessels– Arteries– Capillaries– Veins
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Heart
• muscular pump located between your lungs.
• a sac called pericardium encloses the heart.
• 4 chambers:– the two upper chambers,
which receive blood returning to the heart, are called atria (singular, atrium).
– the two lower chambers are called ventricles, which pump blood out of the heart.
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Valves
• flaps of tissue that prevent blood from flowing backwards
• located between the atria and ventricles and between the ventricles and the arteries leading from the heart
• the opening and closing of the valves cause the “bump bump” sound of the heart.
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Blood Flow: 2 circuits/loops Pulmonary Circuit carries
oxygen-depleted blood from the heart to the lungs and oxygen-rich blood back to the heart. Heart → Lungs → Heart
Systemic Circuit carries oxygen-rich blood from the heart to the rest of the body and oxygen-depleted blood back to the heart. Heart → Body → Heart
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Blood Vessels• Arteries: take blood (with high pressure)
Away from the heart =– thick walls: help withstand high pressure– more smooth muscle: help pump blood, make
the vessel more elastic– small space inside (increases pressure)
• Veins: take blood (with low pressure) back to the heart– thinner walls compared to arteries: less
smooth muscle– have valves to prevent backflow of blood– large space inside (decreases pressure)
• Capillaries: connect arteries and veins/allow exchange of substances between blood and tissues– microscopic: only one cell at a time can go
through them– single-celled wall: allows easy diffusion of
substances– reach every cell in the body
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Diffusion between cells and vessels
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Pacemaker
Group of cells in the right atrium that can produce a contraction
Contraction stimulus is picked up by nerve cells and spread to the rest of the heart
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Nerves and Hormones• The pacemaker is controlled by:
– nervous system• opposing nerves control the
pacemaker by speeding it up and by slowing it down.
– endocrine system• hormones secreted into the
blood also control the pacemaker.
• hormone epinephrine, also called adrenaline, increases heart rate when the body is under stress.
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Blood
• connective tissue made up of cells and liquid.
• blood is pumped through the body by the heart
• you have about 4-6 liters of blood
• it takes about 1 min for blood to make a complete circuit through the body.
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Blood Composition• Plasma is 90% water.
– The other 10% contains: dissolved salts, proteins, hormones, CO2, antibodies, urea, sugar, etc...
• Red Blood Cells– Carry oxygen to the cells– Contain hemoglobin, a protein that stores oxygen
(hemoglobin contains IRON)
• White Blood Cells– Produce antibodies + destroy pathogens = fight
infections
• Platelets– Small fragments of cells that help stop cuts from
bleeding– Release clotting factors that help form protein
threads called fibrin– Fibrin threads trap platelets and blood cells to
make a blood clot.
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Blood Pressure
• consists of two numbers Systolic Pressure– produced when the
ventricles contract Diastolic Pressure– produced when the heart
relaxes
• average blood pressure for healthy adults– 120/80 (120 over 80)
• average heart rate is about 70 beats per minute
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Atherosclerosis• slow build up of plaque (lipids,
cholesterol) inside vessels• arteries become harder, less
flexible• less space for blood• if coronary arteries are affected:
heart attack might happen = heart cells die
• Factors affecting coronary heart disease (CHD):– Age, race, heredity, gender,
cholesterol levels, blood pressure, obesity, diabetes, smoking, sedentary lifestyle, stress
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Health• Cholesterol /fats might clog arteries
= pressure inside vessel increases = hypertension/even heart attack
• Salt also promotes hypertension
• Regular exercise makes the heart stronger
• Smoking increases blood pressure (nicotine is a stimulant = increases heart rate/tar accumulates all over lungs = make gas exchange more difficult/CO stick to red blood cells permanently)