The Circulatory System Flashcards
why do we have a circulatory system
to transport materials around the body
what does the circulatory system consist of?
heart, arteries, veins, capillaries
closed circulation
the blood remains inside the blood vessels
eg dogs, humans most animals
open circulation
the blood is not always found in the blood vessels
eg. insects, spiders, crabs, lobsters
arteries
blood is carried away from the heart under high pressure
veins
blood is carried to the heart under low pressure with valves to prevent backflow
capillaries
join arteries and veins
adaptations of capillaries for the exchange of materials
one cell thick=very permeable
large no of capillaries located close to every body cell
the Heart
a muscular pump needed to pump blood all over the body
what is the heart made of
made of cardiac muscle surrounded by a double membrane called the pericardium
where is the heart located?
in the thorax
in-between the lungs slightly to the left above the diaphragm
what type of muscle is cardiac muscle
involuntary ie does not tire
what is the main structure of the heart
divided into 2 sides by a muscular wall called the septum
what are the 4 chambers of the heart
right atrium, right ventricle, left atrium, left ventricle
what are the 4 major blood vessels of the heart
vena cava, pulmonary vein, pulmonary artery and aorta
what does the pulmonary circuit involve
heart->lungs->heart
what does the systemic circuit involve
heart->body->heart
explain double circulation
deoxygenated blood is pumped from the heart back to the lungs
blood receives oxygen and returns to the heart
the oxygenated blood is then pumped then pumped to the rest of the body
the oxygen leaves the blood to be used for respiration
blood returns back to heart to restart the cycle
what are the 2 circuits ofcirculation
pulmonary
systemic
what are the benefits of double circulation
separation of oxygenated and deoxygenated blood
blood is under controlled higher pressure to reach all parts of the body
higher pressure ensures appropriate metabolism to allow for more activity
what is the blood supply to the heart
coronary artery
where exactly does the coronary artery deliver blood to?
to the heart muscle
what causes a heart attack
blockage of the coronary arteries from the build-up of plaque
what is the cardiac cycle
every time your heart beats the cardiac cycle occurs
it is controlled by the SA & AV nodes
what does SA node stand for
sinoatrial node
what does AV node stand for
atrioventricular node
what are the 2 nodes?
a type of nervous tissue that acts as a pacemaker
how does the cardiac cycle work
- blood enters the heart into the atria
atria + ventricles relaxed
valves closed - blood pumped from atria to ventricles
SA node sends signal causing atria to contract (ATRIAL SYSTOLE)
tricuspid + bicuspid vales open
vena cava + pulmonary vein close to prevent blood entering the atria
3.blood leaves the heart
atria relaxed
AV node sends signal -ventricles contract (VENTRICULAR SYSTOLE)
tricuspid + bicuspid valves shut
semilunar valves open
blood leaves, ventricles relax, valves close & cycle starts over again
pulse
alternate expansion and contraction of the arteries
what is the average pulse for an adult
72bpm
blood pressure
the force exerted by the blood against the walls of the blood vessels
how do you measure blood flow
by measuring the pressure required to stop blood flow in the artery of the upper arm
what are the 2 values measured when measuring blood pressure
systolic + diastolic pressure
systolic pressure
pressure as the blood passes through due to ventricular contraction
diastolic pressure
when there is no pulse, or the ventricles are relaxed
who is at most risk for high blood pressure?
overweight
have a relative with high blood pressure
smoke
eat a lot of salt
don’t do enough exercise
are over the age of 65
what are the 3 factors affecting circulatory health
smoking
diet
exercise
how does smoking effect circulatory health
tobacco contains harmful chemicals such as nicotine and carbon monoxide
nicotine increases heart rate + blood pressure
carbon monoxide reduces the amount of oxygen carried by blood
how does diet effect circulatory health
eating foods high in saturated fat cause high cholesterol which leads to a build-up of plaque which can lead to heart attacks and strokes
foods high in salt lead to high blood pressure
obesity leads to blood being under higher pressure due to the excess weight
how does exercise effect circulatory health
increased exercise leads to a healthier heart
the heart muscle is strengthened and the resting heart rate decreases
what is the lymphatic system?
a one-way system of dead ending vessels
how do lymph vessels work?
they collect fluid from around the cells and return it to the blood
what are lymph nodes
they are swellings in lymph vessels which help fight infection
how does the lymphatic system work?
water from the blood is forced out of capillaries this is called tissue fluid or interstitial fluid, extracellular fluid
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what does tissue fluid consist of?
white blood cells and small proteins
how is tissue fluid drained?
in 2 ways:
90% is drawn back into the capillaries
10% enters the lymph vessels - this creates lymph
what is lymph
a milky white fluid full of proteins, white blood cells and fats
made as a result of tissue fluid entering the lymph vessels
what are lymph vessels
muscular walls of vessels
body movements
do lymph vessels have valves?
yes, to ensure lymph only flows towards the shoulders
what are the 2 main lymph vessels
the thoracic duct (left)
lymphatic duct (right)
where do the thoracic and lymphatic duct empty?
into the bloodstream at the subclavian veins under the collar bones
what are lymph nodes
they are swellings on a lymph vessel
what is the function of a lymph node
they contain lots of white blood cells to fight infection
where are the glands found?
tonsils
neck
armpits
groin
ect
how do nodes fight infection
by filtering bacteria from the lymph
by maturing lymphocytes and storing them
what are the functions of the lymphatic system
to collect tissue fluid and return it to the blood
the defend the body against infection
absorbs and transports fats in the digestive system
how do you distinguish between the front and back of the heart
flat side of the heart is flat
on the front of the heart the coronary artery is running from the top right to bottom left
how do you tell the difference between the left and right side of the heart
the left side of the heart is thicker
why do you use the neck or the wrist to measure pulse?
because the artery is closer to the surface of the skin
what does it mean if you return to a resting pulse faster?
the faster you return to a resting pulse the greater a fitness level you have
