Studied by 73 people
what does the circulatory system consist of? (3)
heart, blood vessels and blood
what is the total length of the blood vessels in the body?
100, 000 kilometers
what is the function of the circulatory system?
to transport various substances around the body
what 5 substances does the circulatory system transport and where are they transported to?
oxygen: lungs to all cells
nutrients: SI to all cells
carbon dioxide: all cells to lungs
urea: liver to kidney to urine
hormones: endocrine glands to all cells
what are the three main types of blood vessels and what do they do?
arteries- carry blood away from the heart
veins- carry blood towards the heart
capillaries- carry blood from arteries to veins
what is the smallest blood vessel?
capillaries
what is interstitial fluid? (3)
-fluid that all the cells of the body “bathe” in
-helps materials pass between body cells and blood
-consists of water, salts, proteins and nutrients
what is a closed circulatory system? do humans have an open or closed circulatory system?
-all blood is found in blood vessels/the heart
-humans have closed systems
what do heart valves do?
prevent blood from flowing backwards
what does the heart do?
pumps blood throughout the circulatory system
where is the heart found?
the chest cavity
what is another name for the chest cavity?
thoracic cavity
what is the heart also known as?
a double pump
what is the pericardium?
a sac surrounding the heart that protects it
define:
a) peri
b) cardium
a) around
b) relating to the heart
what are the four chambers of the heart?
right and left atria, right and left ventricles
which of the two types of heart chambers has thicker walls?
the ventricles
what is the wall that separates the right and left sides of the heart?
the septum
what are the 2 main periods of the heart’s pumping?
systole and diastole
what happens during diastole?
the heart muscle relaxes
what happens during systole?
the heart muscles contract
which heart chambers contract first?
the atria
what causes the lub-dup noise?
heart valves closing
which valves make the ___ sound?
a) lub
b) dup
a) bicuspid and tricuspid
b) semilunar valves
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what is a special ability of the heart/cardiac muscle?
it can keep beating after being removed if it is in a certain substance
what are the two special muscle regions in the heart?
the AV-atrioventricular node and the SA-sinoatrial node
what is the sinoatrial node also known as?
the pacemaker
where is each node found and what do they do?
SA-upper right wall of the r atrium, sets the rate at which the heart contracts
AV- base of the r atrium, has long projections passing down into the ventricle walls
how do the nodes help the heart beat?
the SA node sends out an electrical signal, causing the atria to contract
when the signal reaches the AV, it causes the ventricles to contract
what does blood pressure refer to?
the fact that blood pushes against blood vessels
what happens to blood pressure as blood moves away from the
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it decreases
what causes a pulse?
arteries bulging during systole
how does blood move through the veins?
skeletal muscles beside the vein contract
why are there valves in veins?
to prevent blood from flowing backwards
what is the purpose of coronary circulation?
to supply the heart muscle with blood
which ventricle has the thickest walls?
left
which veins drain directly to the heart’s chambers?
coronary veins
what is atherosclerosis and what does it increase the risk of?
the arteries narrow due to buildup of plaque which increases the risk of heart attacks and strokes
what is coronary artery disease also known as?
atherosclerosis
what causes heart attacks?
buildup of plaque in a coronary artery prevents blood flow to a section of the heart and it dies
what are heart attacks also known as?
myocardial infarction
define:
a) myo
b) infarction
a) muscle
b) death
what are the 3 methods of treatment for coronary artery disease?
coronary bypass surgery, balloon angioplasty and stenting
what happens during coronary bypass surgery?
a vein is removed from somewhere else in the body and grafted behind and in front of the blockage so blood can flow
what happens during a balloon angioplasty?
a small balloon is threaded through the aorta to the blockage and inflates for 60 seconds, flattening the plaque
what happens during a stenting?
a stent is guided to the blockage and remains there, keeping the blood vessel open
what is a stent?
a tiny mesh cylinder
which two treatments for coronary artery disease are often done together?
balloon angioplasty and stenting
what happens during an angiography? (3)
-a catheter is inserted into a blood vessel in the arm or leg and moved to the desired artery
-dye is injected through the catheter which allows X-rays to be taken
-blocked regions are visible
what is an angiogram?
the image/ results from an angiography
what is the placenta and when does it form?
an organ that forms only in pregnant women
what happens to the placenta after birth?
it detaches from the uterus and exits the body
what is afterbirth?
when the placenta exits a woman’s body after a baby is born
what is the point of fetal adaptations?
to divert blood flow away from the lungs
what are the 2 fetal adaptations and what do they do
foramen ovale-a hole in the septum between the right and left atria
ductus arteriosus-artery that connects the pulmonary artery to the aorta
what happens to blood that passes through the foramen ovale and ductus arteriosus?
it bypasses the fetal lungs
what are varicose veins?
veins that have lost their elasticity because valves do not work properly
how do red blood cells pass through capillaries?
in single file
what are the atrioventricular valves? (2)
tricuspid and bicuspid valves
what percent of the ventricle is full after diastole?
70%
what causes a heart murmur?
damaged heart valves
what is an electrocardiogram?
a recording of the hearts electrical currents that is used to determine if the heart is healthy
which nerves regulate the pacemaker? what does each one do? (2)
-vagus nerve: slows the pacemaker
-cardioaccelerator nerve: speeds up the pacemaker
what happens if the natural pacemaker fails?
an artificial pacemaker is surgically placed
what is the average…
a) systolic pressure
b) diastolic pressure
a) 120mmHg
b) 80mmHg
how is blood pressure measured?
using an instrument called a sphygmomanometer
how is blood pressure usually stated?
systolic pressure/ diastolic pressure
what is hypertension?
high blood pressure
what increases the risk of atherosclerosis?
high cholesterol intake
what would happen if all capillaries opened at the same time?
there wouldn’t be enough blood to fill them
what is located at the end of every arteriole?
a ring of muscle
what are the two major pathways of circulation?
pulmonary and systemic circulation
what happens to blood flow when we eat?
it is diverted to the digestive tract
what are the three branches of systemic circulation? what does each branch do?
coronary- supplies the heart muscle with blood
hepatic portal- carries blood from the digestive tract to the liver
renal circulation-carries blood to and from the kidneys where waste is removed
what is interstitial fluid also known as?
intercellular fluid
how is extra fluid and protein in the intercellular space returned to the blood?
the lymphatic system
what is the portal vein?
a vein that brings nutrient rich blood from the digestive tract to the liver
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what happens to blood in the portal vein once it reaches the liver?
nutrients are collected by hepatic sinuses and blood continues to the vena cava
what is a function of the liver?
to absorb and store excess glucose as glycogen
what does the lymphatic system do?
returns excess fluid and protein to the blood
what would happen without the lymphatic system? (2)
-the circulatory system would drain because of the loss of fluid
-body tissue would become flooded and swell up
what is fluid called once it enters the lymphatic system?
lymph
what are lymph capillaries?
microscopic tubes that join together to form larger vessels
what do lymphatic vessels have in common with veins?
they have valves
what is the thoracic duct?
the largest lymphatic vessel in the body
where do the thoracic and right lymph ducts empty into?
a large vein in the neck
what do lymph nodes do? (3)
-filter foreign matter from lymph
-produce some white blood cells
-become swollen around infected areas
what do lymphoid tissues do in the spleen?
filter bacteria and worn out red blood cells from the blood
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