Health Science 2211-Lecture 3
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Health Science 2211-Lecture 3
blood vessels anatomy
blood vessels anatomy
what are the 3 layers that blood vessel consists of?
what are the 3 layers in the
? Briefly describe each.
continuous with endocardium
for endothelial layer
Internal elastic lamina
: thin layer of
what are the 2 layers in the tunica media? Briefly describe them.
smooth muscle cells and elastic tissue:
give blood vessel structure
external elastic lamina
: another layer of elastic tissue
what is the function of the tunica media and how does in differ between blood vessels?
diameter of the vessel
thinner in veins
than in arteries
what does the tunica externa consist of, what is it supplied with and what is it's function?
elastic and collagen fibers
nerves and blood vessels (vasa vasorum)
function is to
anchor vessels to surrounding tissue
what are 4 functions of endothelial cells?
block passage of large molecules out of lumen, into tissues
control vascular smooth muscle cells
various roles in inflammation, repair
what do the endothelial cells interact with? (3)
other endothelial cells
what are the 4 function of smooth muscle?
give blood vessel
helps regulate blood flow/pressure
maintains extracellular matrix by building and
secreting elastin, collagen
can proliferate to repair damaged blood vessel
what are the 2 main circulations?
: short loop runs from right side of heart to the lungs and back to the heart
: long loop from
left side of the heart to all parts of the body and back to heart
what are the 3 ways that blood return back to the heart?
superior venae caveae
inferior venae caveae
larger diameter, thinner walls and less elastic tissue
than systematic tissue?
less pressure is needed to move blood through the lungs
(less distance less resistance)
Arterioles, capillaries and venules
are collectively referred to as?
what is one thing different regarding structure in arteries compared to veins? what are the 2 types of arteries?
arteries have a
thick tunica media
elastic arteries (conducting arteries)
muscular arteries (distributing arteries)
contraction of smooth muscle
, squeezing the vessel wall and
narrowing the lumen of the blood vessel
smooth muscle fibers relax and lumen diameter increases
Describe the structure of elastic arteries and what is its function?
more elastic fibers and less smooth muscle
receive blood under pressure
propel it onward
function as a
why are elastic arteries also called conducting arteries?
conduct blood from the heart to medium sized muscular arteries
Describe the structure of muscle arteries and what is it's function?
medium-sized arteries with more smooth muscle than elastic fibers
in tunica media
modifying the diameter to adjust rate of flow
through vasoconstriction and vasodilation
why are muscular arteries also called distributing arteries?
direct blood flow and distribute blood to specific parts of the body
what are arterioles and what are its 2 functions?
very small arteries
regulate blood flow into capillaries
altering arterial blood pressure
what is the structure for arterioles closer to the capillaries? (3)
endothelium, smooth muscle cells, and a thin layer of connective tissue
what are capillaries and what is it's function?
microscopic vessels that connect arterioles to venules
exchange of nutrients and wastes between blood and tissue fluid
what is the structure of capillaries? (2)
endothelium and basement membrane
describe the structure of venules and what cannot it withstand?
thin walls that do not readily maintain their shape
not designed to withstand
Blood flow through body tissues, also called
is involved in (5)?
delivery of O
nutrients & water
throughout body and
removal of wastes from tissue cells
absorption of nutrients
in digestive tract
maintaining body temperature
what is blood flow?
of blood moving past a point in a given amount of
Blood flows from a region of______ pressure to _____ pressure
High to low
The greater the _____________the greater the blood flow.
the more _________ the less blood flow.
What are 4 factors that affect blood flow?
vascular resistance to flow
velocity of blood flow
What is blood pressure and what is caused by?
pressure exerted by blood walls of a vessel
caused by contraction of ventricles
what is a regular blood pressure?
Increasing what 2 factors increases your arterial blood pressure?
What is vascular resistance?
force opposing the flow of blood due to friction of blood and the vessel walls
what two mechanisms can be powerful regulators of blood pressure??
vasoconstriction and vasodilation
What does blood viscosity depend on and how does it increase blood pressure?
depends mostly on
ratio of red blood cells to plasma (fluid) volume
high viscosity=high resistance=high blood pressure
How does being obsess increase your chance of blood pressure?
being over weight increases
the total blood vessel length
creates more resistance
which leads to increased blood pressure
Most of the pressure driving the return of blood to the heart comes from _________________.
left ventricular contraction
when standing, ________ opposes flow up to heart, almost overcoming upward pressure.
What are 2 supplementary pumps that help out with venous return?
skeletal muscle pump
how does the respiratory pump help with venous return? (in regards of breathing and the diaphragm)
breathing helps bring blood back to the heart
the movement of the
area of lower pressure around the heart
, and an area of
higher pressure in the abdomen
, which pushes blood up to the heart
what is the function of valves in large veins on the legs?
prevents the backflow of blood
how does the skeletal muscle help with venous return?
as skeletal muscles contract,
they compress the veins
valves above the contracting muscle in the skeletal muscle pump to open and allow blood to move to the heart
what is the function of valves above the contracting muscle in the skeletal muscle pump?
the open allowing blood to move toward the heart
what is the function of valves below the contracting muscle in the skeletal muscle pump?
are forced closed, preventing backflow of blood to the capillaries
what is the velocity of blood in arteries,veins and capillaries?
fastest in arteries/aorta
slowest in capillaries
increases speed again in veins
what are the 2 systemic regulation of blood pressure?
what are the 2 auto-regulation of blood pressure?
what are the 4 inputs to the cardiovascular center in the brain?
from diff parts of the brain:
anticipation of competition, increase in body temperature
input during physical activity
changes in pressure withing blood vessels
monitor concentration of chemicals in the blood
what is the output from the cardiovascular center? (3)
Heart rate increases or decreases
contractility of the heart can increase or decrease
Blood vessels can go through vasoconstriction or vasodilation
how are hormones used for regulation of blood pressure?
increase secretion of urine ---> decreases blood volume ---> which decreases blood pressure
how do metabolic controls, control regulation of blood pressure? (2)
local factors can cause change in each
(increases in activity of an organ will increase blood flow to that organ)
released from cells alter vessel diameter
In myogenic controls of regulation of blood pressure, myogenic responses of arteriolar vascular smooth muscle keep tissue perfusion ________________?
constant despite most fluctuations in systemic blood pressure
what is passive stretch?
increased intravascular pressure
promotes increased tone and vasoconstriction
acting to resist the initial passive stretch
what is reduced stretch?
promotes vasodilation and increases blood flow to tissue
An example of long term auto-regulation of blood pressure is angiogenesis? when does is occur?
occurs when short-term auto-regulation cannot meet tissue nutrient requirement
number of vessels to a region increases and existing vessels enlarge
what is a pulse?
pressure waves caused by the expansion and recoil of arteries
what is systolic pressure?
peak arterial pressure during heart contraction
what is diastolic pressure?
minimum arterial pressure between contractions, when the heart expands and refills
One way to measure blood pressure is through the
. what is it?
using a sphygmomanometer and stethoscope
Blood pressure cycles over a ______________.
24 hour period
when does blood pressure peak and what are some things that can increase blood pressure?
peaks in the morning
due to levels of hormones
age, sex, weight, race, mood, and physical condition
may vary BP
Blood pressure increases with ___________ resistance and _________ cardiac output.
what is hypotension? what is it often associated with?
low blood pressure
associated with long life and lack of cardio vascular illness
what is hypertension? where is it more persistent?
high blood pressure
often persistent in obese people
what are the 3 types of hypotension?
what is orthostatic hypotension?
low BP and dizziness
suddenly rising from sitting position
what is chronic hypotension?
hint of poor nutrition
and warning sign Addison's disease
low protein decreases viscosity of the blood
what is acute hypotension?
important sign of circulatory shock
what is shock? what does it result in?
failure of the cardiovascular system to deliver adequate amounts of oxygen and nutrients to body tissues
results in cells and tissue becoming
damaged or dying
what are the 4 types of shock? Briefly describe each.
: due to decreased blood volume ex. hemorrhage
: due to poor heart function
: due to excessive vasodilation (causes drop in BP, ex. allergies)
: due to obstruction of blood flow (ex. embolism)
what number is defined as hypertension?
what is primary hypertension?
90-95% of all cases
elevated BP that
cannot be attributed to any particular organic cause
what is secondary hypertension?
5-10% of all cases
identifiable underlying cause
such as obstruction of renal flow