Lesson 20: Topic 16 - Intro to Vascular Flashcards
what are the functions of the vascular system?
- delivery of O2 (most important)
- removal of CO2
- nutrient delivery
- removal of waste
- distribution of hormones
- transport of immune cells
- temperature control
why does CO2 need to be removed from the body?
it can impede basal function due to acidosis
what is selective distribution of the vascular system?
- not all tissues receive equal blood volumes
at rest, what percentage of our blood goes to skeletal muscle?
15%
when we exercise, our blood percentage distribution to each organ changes. what has the most significant increase?
the skeletal muscle
- percentage depends on intensity and duration of exercise
what is the components of the vascular network?
- pulmonary circulation
- systemic circulation
what is the pulmonary circulation?
from the heart to the lungs
what is the systemic circulation?
from the heart to all other tissues except the lungs
is the aorta a vein or artery?
artery
which blood vessels carry oxygenated blood?
pulmonary veins and systemic arteries
which blood vessels carry deoxygenated blood?
pulmonary arteries and veins
what is macro-circulation?
takes blood to or from organs
ex. arteries and veins
what is micro-circulation?
distributes blood within each organ
ex. arterioles and venules and capillaries
what type of cell forms the inner layers of ALL blood vessels?
endothelial cells
what are the layers of an artery?
from inner to outer:
- endothelium
- basement membrane
- elastic fibres
- smooth muscle
- elastic fibres
- connective tissue coat (mostly collagen fibres)
what are the layers of an arteriole?
- endothelium
- basement membrane
- smooth muscle
- connective tissue coat (mostly collagen fibres)
- same as artery except they do not have elastic fibres
why does arteries have thick elastic walls?
to withstand high pressure
what is the thickest layer in both the arteries and the arterioles?
smooth muscle
the muscular walls of an arteriole control?
blood flow (ie, control valves for capillary beds) to tissues
the thin walls of capillaries allow for?
exchange of gases, nutrients, fluids
what are the two wall layers of a capillary?
- endothelium
- basement membrane
what are the wall layers of a vein?
- endothelium
- basement membrane
- smooth muscle; elastic fibres
- connective tissue coat (mostly collagen fibres)
veins have thin walls compared to?
arteries
what is the pressure system like in veins?
low pressure system
why does veins have a low pressure system?
because blood in the veins comes from blood in the arteries that passed through the tissues so the pressure is lost and distributed
how are veins a blood reservoir (reserver?)?
because the have venous valves to keep blood
what is the thickest layer of wall in the vein?
smooth muscle
do veins have a lot of elastic fiber?
they have very little (it is there thinnest layer)
what is the thinnest wall layer of an arteriole?
the collagen fibers
does arteries have a thick elastic fibre layer?
yes, they have two
what is the equation for flow?
flow = Pressure / resistance
** ** ** how can flow be related to cardiac output?
cardiac output = (mean arterial pressure - right arterial pressure) / total peripheral resistance
- HOWEVER, right atrial pressure typically = very close to 0
- SO
- CO = MAP / TPR ***
does absolute pressure determine blood flow?
no. only pressure gradient
- the pressure GRADIENT along the length of the tube determines blood flow
does pressure increase or decrease as it goes from left ventricle to arteries, to arterioles, to capillaries to venules and veins?
decreases
does the pressure in arteries ever go to 0?
no, there is always blood in arteries so they will always have a pressure
what is the diastolic pressure in the aorta?
about 80 mmHg
what is the diastolic pressure in the left ventricle?
about 0 mmHg
is there a continuous or discrete pressure gradient from arteries to veins?
continuous
where does the largest pressure drop across blood vessels happen?
largest pressure drop at the level of the arterioles
if diastolic blood pressure is 80mm Hg in a systolic heart failure patient, what would be the pressure gradient in the aorta if systolic blood pressure reached 80mm Hg?
0mm Hg
- this is because diastolic BP is the lowest and systolic BP is the highest so 80 - 80 = 0mm Hg
