1.2 Blood vessels Flashcards
do a blood vessel carry BOTH (CO2/waste) and (O2/nutrients)
give an example
- no
- a blood that carries (CO2/waste) and (O2/nutrients) are carried by separate blood vessels
- The blood that leaves the heart through the aorta is rich in oxygen and nutrients. This blood must be pumped in separate vessels from the blood that is full of carbon dioxide and wastes
function of the blood vessels
transport the blood to all parts of the body
what pumps the blood
the heart
what are the 3 types of blood vessels
- artery
- veins
- capillaries
Artery vs Veins
3 info
ARTERY
- carries blood away from the heart
- a thick-walled blood vessel
- no valves
VEINS
- carries blood toward the heart
- thin-walled blood vessels
- has valves
why must every living cell have to be close to a capillary
capillaries are thin walled porous vessels that allow materials from the blood, such as gases and fluids, to be exchanged with the body cells.
= it is where cells get there food and get rid of their waste
Therefore, every living cell must be close to a capillary to remain alive and functioning
what is the smallest and narrowest blood vessel
capillaries
what happens within the capillaries
blood exchanges O2 and glucose for wastes like CO2 from the cells
- (CO2/wastes) diffuse FROM cells and INTO the blood
- (O2/nutrients) diffuse FROM blood and INTO the cells
talk about the capillaries walls
the walls are only one cell thick for exchange of gases to take place by diffusion exist in capillary bed
Capillary bed
a web of capillaries surrounding the cells of the body tissues
how do the arteries and veins effectively reach every part of the body
both arteries and veins both branch into smaller vessels called arterioles and venules to effectively reach every part of the body
what is the largest veins int the body
venae cavae
steps about the hearts right side in more detail
- deoxygenated blood arrives to the heart from the body’s major veins, which flows into the venae cavae, the largest veins in the body
- the blood from each venae cavae is carried to the hearts right side where it is pumped to the lungs through the pulmonary arteries
- Within the capillaries of the lungs, the blood exchanges CO2 for O2 = oxygenated blood
- the oxygenated blood then returns to the heart’s left side through the pulmonary veins
Pulmonary circulation
the movement of the blood into and out of the lungs
what is the largest artery in the body
aorta
where do the coronary artery appear?
on the surface of the (R) and (L) ventricles of the heart
Pulmonary vein
the large blood vessel that carries oxygenated blood away from the lungs and into the hearts left atrium
Pulmonary artery
the large blood vessel that carries O2 poor blood away from the heart’s right ventricle and into the lungs
why do arteries have thick elastic walls
to withstand (not be damaged) the high PRESSURE exerted by the pumping heart. Except in this case of the pulmonary artery
As arteries get farther away from the heart and aorta …
they branch out and get smaller in diameter and lower in pressure. These smaller branched arteries are called arterioles
Arterioles
- a small artery that joins a larger artery to a capillary
- smaller in diameter and lower in pressure
- attached to a capillary
arterioles are attached to
capillaries
Venule
a small vein that joins a larger vein to a capillary
why does the wall of the veins / venules does not need to be thick and elastic as the walls of the arteries
the blood in venules and the larger veins has much lower pressure than the blood pressure in an artery
how does the low-pressure blood get back to the heart against the pull of gravity
example
- one way valves in the veins that prevents back flow of the blood
- the action of the contracting muscles.
the moving muscles push on blood in the veins while one-way venous valves prevent a back flow of blood and direct the blood back toward the heart
what if the veins become stretched and the valves are damaged
blood in the veins pools and the veins become raised in a condition called varicose veins
Varicose Veins
an enlarged, twisted vein near the surface of the skin resulting from poorly functioning valves
Blood pressure (2)
- the pressure exerted by the blood against the walls of blood vessels
- the pressure exerted by the blood on the walls of a MAJOR artery
Gauge
explain how it works
measure pressure in terms of height that a column of mercury can be raised
- the greater the pressure, the higher the column of mercury rises in the tube
what forces the blood to flow through the body’s blood vessels
BP
2 pressures are measured with blood pressure because…
Since the heartbeat has a cycle of contraction and relaxation
what is the 1st # in blood pressure reading
larger systolic pressure
Systolic pressure
- represents what
- what happens to the walls of the arteries
- the pressure exerted on the artery walls when the heart’s ventricles are contracting
- represents the pressure in that arteries when the heart ventricles are contracting
- stretch slightly in response to the pressure
what connects the arterioles (artery) to venules (veins)
capillary
what kind of blood does capillary has
BOTH oxygenated and de-oxygenated blood
aorta
carries O2 rich blood away from to heart and directs it to the entire body
what happens within the capillaries of the (R) and (L) lungs
the O2 poor blood releases its CO2 and receives O2 = becomes oxygenated
what happens to the BP within a blood vessel as it get farther from the heart
it gradually decreases
- There is less blood pressure in the artery of your big toe, for example than in your left arm.
why do capillaries walls are one-cell thick
they need to be thin enough so that the gases can diffuse through it during gas exchange between the blood and cells
what happens to the cell and blood within a capillary bed
BLOOD= depletes in O2 and nutrients | receives CO2 and wastes
CELLS= depletes in CO2 and wastes | receives O2 and nutrients
why do blood vessels have elastic walls and why the thickness of the elasticity varies
- it is all about the pressure exerted on the blood vessels walls (aka BP) by the blood
- THICK elastic walls = High BP, and so thick elastic walls are essential to avoid being damaged by the high BP
- THIN elastic walls = Low BP, and so thin elastic walls aren’t really needed because there are less pressure exerted on the blood vessel wall meaning there aren’t really any damage on the blood vessels walls being done
What is the purpose of a “one-way valve”
to prevent back flow of blood
what happens to the speed of blood flow…
relate it to the pressure exerted by the heart (BP)
- the higher pressure exerted by the heart (BP) the faster the blood flow will travel
- the lower pressure exerted by the heart (BP) the slower the blood will flow
the STEPS for getting blood back toward the heart by a vein through muscle contraction (4)
1) muscle contract
2) the vein is squeezed
3) this creates pressure that opens the top valve
4) blood moves toward the heart
which people has the greater tendency to develop varicose veins
people who sends their day standing
which blood vessel is being measured when trying to determine blood pressure
a MAJOR artery
BP info thingy
(pressure exerted by the blood in the artery)=(pressure exerted by air in cuff)=(pressure exerted by column of mercury)
(pressure in the column of mercury)=(pressure of the blood in the artery)
2nd number in blood pressure
-represents..
- diastolic pressure (smaller value)
- represents the residual in the arteries when the heart’s ventricles are relaxed and chambers are refilling
diastolic pressure is due to..
the elastic walls of the arteries attempting to return to it previous shape between the ventricle contraction because the artery walls was stretch slightly during when the heart ventricle contracted
how does the blood vessel deal with the high pressure exerted by the heart
their elastic walls will stretch in response
blood pressure is written as…
(systolic pressure/diastolic pressure)
blood pressure communication (3)
..
normal BP for adults..
(90-135mmHg) / (50-90mmHg)
hypertension
- definition
- value
- high blood pressure
- higher than (140/90)
BLOOD PRESSURE IN DIFFERENT BLOOD VESSELS
- Aorta - arteries and some of the arterioles
(2) - Arterioles - capillary - venule - veins - vena cava
(2)
- Aorta - arteries and some of the arterioles
- BP here is the highest kong there other blood vessels
- BP fluctuates here
- Arterioles - capillary - venule - veins - vena cava
- BP here gradually decrease as it passes through each blood vessel
- no fluctuation except part of arterioles
which blood vessel deals with the HIGHEST BP
- aorta (closest to the heart and its an artery,)
arteries has a higher BP than veins
which blood vessel deals with the HIGHEST BP… veins or arteries
arteries
which blood vessel deals with the LOWEST BP
vena cava (its vein)
CROSS SECTION AREA
- what blood vessels has THE SAME cross sectional area
- what vessels has the LOWEST cross-sectional area
- what vessels has the GREATEST cross-sectional area and why…
- cross-sectional area from GREATEST to LOWEST
- what blood vessels has THE SAME cross sectional area
- aorta / vena cava
- Artery / vein * Arterioles / venule
- what vessels has the LOWEST cross-sectional area
- aorta and vena cava (the LARGEST blood vessels)
- what vessels has the GREATEST cross-sectional area
- capillary ( the SMALLEST blood vessel) because there are more capillaries than any other blood vessels
- cross-sectional area from GREATEST to LOWEST
- capillaries
- arterioles / venule
- arteries / veins
- aorta / vena cava
INCREASE in cross-sectional area = ___ speed blood flow
INCREASE in cross-sectional area = DECREASE speed blood flow
SPEED OF BLOOD FLOW AS IT TRAVELS THROUGH BLOOD VESSELS
- where the speed of blood flow is the FASTEST
- where the speed of blood flow is the SLOWEST
- where the speed of blood flow gradually DECREASES
- where the speed of blood flow starts to increase AFTER it decreased in capillary
- where the speed of blood flow is the FASTEST
- aorta
- where the speed of blood flow is the SLOWEST
- capillaries
- where the speed of blood flow gradually DECREASES
- when it starts to flow through “arteries” and “arterioles”
- where the speed of blood flow starts to increase AFTER it decreased in capillary
- when it flows throughout he “venules” and “veins”
remember the graph for
- BP
- cross-sectional section
- speed of blood flow
okay
what happens to BP as is passes through..
- aorta
- arteries
- arterioles
- capillaries
- venules
- veins
- vena cava
the BP gradually decrease as it passes through each blood vessel
fluctions in BP = _____
fluctions in BP = pulse exist
BP fluctuation / pulse exist in what blood vessels
- aorta
- arteries
- some part of arterioles
NO BP fluctuation / NO pulse in what blood vessels
- some part of arterioles
- capillaries
- venules
- veins
- vene cava
why blood travels slowly within the capillary bed
to enhance to exchange of substances between the blood and body cells
what happens to the blood flow speed as it leaves the capillaries
blood flow gradually speeds up due to the decreasing cross-sectional area
why BP drops as it flows through the capillary (3)
- due to the INCREASING cross sectional area
- narrow openings
- gas/material exchange
veins vs. arteries “blood flow speed comparison”
blood flow speed in the veins is much slower than the speed through the arteries
what is the source of the residual pressure of the diastole pressure
the slight contraction of the arteries elastic walls as the attempt to rebound from the slight stretching caused by the previous heart contraction
ABOUT BP
- if BP is too high, what will happen
- if BP is too low, what will happen
- how the body controls BP
> during low BP
> during high BP - why BP reading may vary from person to person (3)
- if BP is too high, what will happen
- blood vessels might burst
- if BP is too low, what will happen
- may cause dizziness or fainting
- how the body controls BP
> during low BP : blood vessels will constrict or narrowed
> during high BP : blood vessels will dilated or widen - why BP reading may vary from person to person
- strength of heart contraction
- rate of heart contraction (how fast or how slow)
- elasticity of the arteries
what affects BP (3)
- strength of heart contraction
- rate of heart contraction (how fast or how slow)
- elasticity of the arteries
what causes “high” BP
- level of anxiety
- exercise
- greater than normal amount of blood within the blood vessels
- viscosity (thickness) of blood
- caffeine
- narrowing blood vessels due to abnormalities going on on the blood vessels walls
where is the pressure that the heart exerted on the blood transferred to?
onto the artery walls