Circulatory System (Lymphatics Pt 1) Flashcards
Cardiovascular System + Lymphatic System =
Circulatory System
Components of Cardiovascular System
heart, blood vessels, blood
Components of lymphatic System
Lymph nodes, lymphatic vessels, and lymph
Goals of the Vascular System
- Arterial supply delivers oxygen-rich blood to cells/tissues/organs
- Venous drainage carries away oxygen depleted blood from cells/tissues/organs
- Capillary networks act to exchange oxygen and nutrients for carbon dioxide, as the
go-between for arteries and veins
Arterial supply delivers oxygen-____ blood to cells/tissues/organs
oxygen rich
Venous drainage carries away oxygen depleted blood from ____
cells/tissues/organs
Capillary networks act to exchange oxygen and nutrients for _____, as the
go-between for arteries and veins
carbon dioxide
Where does the exchange of oxygenated vs deoxygenated blood occur?
Capillary beds
Arteries are traveling ______ the heart and veins are traveling ___ the heart
Arteries (away) Veins (to)
The heart acts as two muscular pumps that act in
series, dividing the circulation into two
components:
Pulmonary and Systematic Circulation
In ______ Circulation: Low-oxygen blood returning from systemic
circulation is propelled into the lungs by the right
ventricle (RV)
Pulmonary
In Pulmonary Circulation: carbon dioxide exchanged for oxygen in the
____ of the lungs
capillaries
Oxygen-rich blood is returned to the ____ via
the pulmonary veins of the lung
left atrium
In Pulmonary Circulation: Oxygen-rich blood is returned to the left atrium via
the _____ of the lung
pulmonary veins
In Systematic Circulation: Oxygen-rich blood returning from pulmonary
circulation is propelled through ______
systemic arteries
(aorta and its branches)
(Systematic Circulation)
In tissues, ____ are exchanged for _______ in the body’s capillaries
oxygen and nutrients exchanged for CO2
(Systematic Circulation)
Low-oxygen blood is returned to the _____
via systemic veins (tributaries of superior and
inferior vena cava)
right atrium
What is special about the pulmonary artery?
Only artery in the body transporting oxygen-poor blood
In pulmonary circulation: blood coming from ___ and eventually entering _____
Right ventricle, left atrium
In systematic circulation: blood coming from ___ and eventually entering _____
left ventricle to right atrium
Systemic Circulation Contains Many
____ Circuits
Parallel
_____ arteries serve the various regions
and/or organ systems of the body
Systemic
How are blood vessels named?
Blood vessels share names with either the
body region they traverse or the bone next to
them
- Some are named for the structure they supply
– connections between multiple branches of
an artery provide numerous potential detours for blood flow
in case the usual pathway is obstructed
Anastomoses
Examples of obstructions of blood flow that may result in utilization of anastomoses:
- Compression of artery due to position of a joint
- Pathology
- Surgical ligation
– smaller alternative channels of blood
flow can increase in size over time if a main channel is
occluded
Collateral Circulation
What is collateral circulation?
– smaller alternative channels of blood
flow can increase in size over time if a main channel is
occluded
large network of blood vessels within an
organ system
Vascular plexus
Vascular plexus that drains blood from
vertebral canal,
bones, and bone
marrow
Internal vertebral
venous plexus
Arteries and veins consist of three tunic layers:
Tunica adventitia/externa, Tunica media, Tunica intima
inside of blood
vessel (contains blood)
lumen
Outermost layer of a blood vessel
Tunica adventitia/externa
What fibers are found in Tunica adventitia/externa? What tissue is it?
collagen and elastic fibers; contains nerve fibers; Connective tissue layer
Layer of blood vessel that helps anchor the vessel to other tissues, protects and
supports vessel
Tunica adventitia/externa
–Middle, muscular layer of a blood vessel
–Usually containing smooth muscle under autonomic
control
–most variable layer
Tunica media
Tunica Intima is what layer of a blood vessel? What is type of tissue is it?
Innermost; endothelial layer
–Single layer of flattened epithelial cells (endothelium)
–Supported by a basement membrane
–Closest to lumen of vessel
Tunica Intima
Capillaries only contain this layer
Tunica intima (endothelial layer)
Smooth muscle in tunica media is under ____ control
autonomic control (sympathetic and
parasympathetics)
Vasoconstriction – narrowing of blood vessel lumen (muscle _____)
contraction
this layer of a blood vessel is involved with vasodilation and vasoconstriction
Tunica Media
____ pressure created by:
* Elevated pressure of blood from being “pumped” by
the heart
* Elastic nature of the arterial walls
* Minimum amount of pressure from gravity
Hydrostatic Pressure
T/F: Hydrostatic pressure will affect the movement of
materials into capillaries
False: Hydrostatic pressure will affect the movement of
materials out of capillaries
Arteries: Tunica Adventitia consists of
Elastin and collagen
* Vasa variorum (vessels of vessels
Arteries: Tunica Media characteristics and contents
Very robust
* External elastic lamina
* Smooth muscle
Arteries: Tunica Interna consists of
Internal elastic lamina
* Endothelium and basement membrane
Blood passes through arteries of
____ caliber
decreasing
These arteries:
* Walls ~10% vessel diameter
* Well defined elastic laminae
* Thick tunica media (elastic lamellae)
* Functions as pressure reservoir
Large elastic (conducting arteries)
–largest
Name the Artery:
–Thick, muscular tunica media
* Walls ~25% vessel diameter
* Vascular tone (can decrease their diameter, or vasoconstrict, to regulate
flow of blood to different parts of the
body as required by circumstance
Medium muscular (distributing)
arteries
Arteries: under autonomic control (sympathetic =
vasoconstriction)
* Walls ~50% vessel diameter
* Thin tunica interna and thin internal elastic lamina
Small arteries and arterioles (resistance vessels)
Small arteries and arterioles (resistance vessels): The degree of filling the capillary beds and the arterial
pressure is regulated by ____ in
smooth muscle of arteriolar walls
degree of tonus (firmness)
receive blood from arterioles, exchange fluids and
materials with interstitial fluids, drained of blood by post-
capillary venules
capillaries
Capillaries are _____ tubes, and are generally
arranged into capillary beds (networks that connect the
arterioles and venules)
simple endothelial
The blood enters capillary beds through ___ that control
the flow and is drained by the ____
arterioles; venules
Capillary anatomy:
* Only a tunica ____ with endothelium and basement membrane
* Diameter is about 5-10um - only slightly larger than diameter of a
single erythrocyte (RBC)
tunica interna
Medium Muscular Arteries: _____ (can decrease their
diameter, or vasoconstrict, to regulate
flow of blood to different parts of the
body as required by circumstance
Vascular tone
Veins: Generally low-oxygen blood in veins, except for
____ bringing oxygenated blood from lungs
to left atrium of heart
pulmonary veins
Veins normally do not pulsate or spurt blood when severed..why?
venous pressure low compared to arterial pressure
Are veins or arteries more abundant? Which is larger?
Veins are more abundant than arteries and are usually larger
than corresponding artery
____ tend to act as blood reservoirs and hold about 60%
of the body’s blood at rest at any given tim
Veins
Anatomy of a vein: Tunica adventitia consists of
Elastic and collagen
Describe the Tunica Media of Veins
Thin, some smooth muscle
What is special about the Tunica interna of some veins?
Some veins have valves formed from endothelium that
create unidirectional flow of blood
Blood passes through veins of ____ caliber
increasing
Multiple ____ can form a small veins, which
make up venous plexuses
venules
What is the thickest layer of the smallest type of veins?
The thickest layer of venules is the Tunica Adventitia (has thin media and interna)
Type of veins:
–Drain venous plexuses
–Can have valves, if in limbs, to prevent reflux of
blood distally
Medium veins
Type of vein:
–Have wide bundles of longitudinal smooth muscle
–Well-developed tunica adventitia
Large veins
Large veins have wide bundles of ____ smooth muscle and well-developed ____
bundles of Longitudinal smooth muscle and well-developed tunica adventitia
Valves are associated with this type of vein:
Medium vein
Venous blood gets back to the heart through:
Venous valves, Accompanying veins (venae comitantes) and vascular
sheaths, and Musculovenous pump
Venous Valves: Prevent backflow of venous blood due to gravity or ___
internal pressure
Veins tend to be double or multiple (compared to arteries), and
those that surround deep arteries can form ____
an irregular branching
network
____ – vascular sheath forces veins to stretch and
flatten as the artery expands during contraction of the heart, which
aids in driving venous blood toward the heart
Arteriovenous pump
serves as countercurrent heat exchanger
vascular sheaths and accompanying veins
____ veins are more likely to anastomose than arteries
Systemic
Musculovenous pump: Contraction of skeletal muscles in limbs, limited by the ____ , compress the deep veins around the muscles –> slowly
pushes venous blood in the only direction it can go, which is towards
the heart
surrounding
deep fascia
Musculovenous pump: what does this compression result in?
pushes venous blood in the only direction it can go, which is towards
the heart
Outward expansion of muscles limited by deep fascia becomes ___
compression
Within and around skeletal
muscle inside the deep fascia
(in neurovascular sheath)
- Arteriovenous pumps
- Typically, these are the
muscular veins that run with
named arteries
Deep veins
–External to deep fascia so not
affected by muscle
contraction
–Have multiple perforating
veins along their course to
continuously shunt blood to
the deep veins to assist in
returning blood to the heart
Superficial veins
T/F Arteries tend to be found at more
superficial positions in the body
relative to veins
FALSE: Veins tend to be found at more
superficial positions in the body
relative to arteries
Superficial Veins: Have multiple perforating
veins along their course to
continuously shunt blood to
the deep veins to assist in
____
returning blood to the heart
_____ can result from veins that
lose their elasticity and become weak
–Leads to swollen, twisted veins often in the
legs
–Can also be caused by incompetent deep
fascia making musculovenous pump
ineffective
Varicose veins
Weakened veins ____ under the pressure
of supporting a column of blood against
gravity
dilate
Varicose veins have a ____ caliber than
normal, and their valve cusps do not meet
up or have been destroyed by
inflammation (incompetent valves)
greater
Capillary exchange: Arterial side is rich with nutrients and
oxygen and has a higher ____
blood pressure
(hydrostatic pressure)–to push water
outward
Capillary exchange: Blood contains lots of proteins, like
albumin, and capillaries are mostly
____ to releasing proteins.
impermeable
Blood contains lots of proteins, like
albumin, and capillaries are mostly
impermeable to releasing proteins. Negative
charge of proteins attracts water. This
creates _____
high oncotic or osmotic pressure (to
pull water inwards)
T/F: Interstitial space of capillaries has very hight protein conc.
Interstitial space has very low protein conc.
Capillary Exchange: On arterial side, ___is higher than
____ so there is a net outward flow of
water, nutrients, and oxygen.
hydrostatic P higher than oncotic P
Capillary Exchange: On arterial side, ___ is higher than
___ so there is a net outward flow of
water, nutrients, and oxygen.
hydrostatic P is higher than oncotic P
Capillary exchange: On arterial side, hydrostatic P is higher than
oncotic P so there is a net ___ flow of
water, nutrients, and oxygen.
outward
Capillary exchange: On venous side, the ____ remains the
same; however, the ____ as
the blood pressure continues to decrease.
oncotic P remains same. hydrostatic P drops as blood pressure decreases
In capillary exchange: When the oncotic P is higher than
the hydrostatic P there is net
____ flow of water, wastes, and carbon
dioxide.
inward
Capillary Exchange: Not all fluid in interstitial space is returned
to the vascular system, so interstitial fluid
remains. It is taken up by _____ that will ultimately return the
fluid to the venous system.
lymphatic
capillaries
Not all fluid in interstitial space is returned
to the vascular system, so interstitial fluid
remains. It is taken up by lymphatic
capillaries that will ultimately return the
fluid to the ___
venous system
Direct connections between the small arterioles and venules proximal to capillary beds they supply
and drain are called _____
arteriovenous anastomoses (AVAs)
Permit blood to pass directly from arterial to venous side of circulation without passing through capillaries
* Found in the fingers
arteriovenous anastomoses (AVAs)
____ are numerous in the skin, where they play a role in conserving body heat
* Connection between metarteriole and thoroughfare channel
Arteriovenous (AV) shunts
3 Types of Capillaries:
continuous, fenestrated, and discontinuous (sinusoid)
Type of Capillary found in Suprarenal glands,
spleen, liver, anterior
pituitary
Discontinous (Sinusoid)
Rank capillaries from most to least leaky:
discontinuous (sinusoid), fenestrated, and
continuous,
a vascular arrangement in which blood from the
capillaries of one organ is transported to the capillaries of another organ
by connection vein(s)
Portal System
(Portal System) Blood passes through ___ capillary beds before returning to heart
two
Three main portal systems:
hepatic (liver), hypophyseal (pituitary), and
renal (kidneys
– venous system by which nutrient-rich blood
passes from the capillary beds of alimentary tract to the capillary beds (or
sinusoids) of the liver
Hepatic portal system
Portal System relating to the pituitary
hypophyseal
T/F: All fluid and electrolytes in the interstitial
(extracellular) spaces from the blood capillaries
is also reabsorbed
False; As much as 3 liters each day fails to be
reabsorbed
Amount of interstitial fluid remains fairly
constant under normal conditions because of
the lymphatic system
