Chapter 19: Cardiovascular System Flashcards
What are the three types of blood vessels?
arteries, capillaries, veins
Arteries carry blood ______________________
away from the heart
Veins carry blood _________________________
toward the heart
What do capillaries do?
contact tissue cells
What are some of the physical differences between an artery and a vein?
Artery: contain a muscular wall, thicker,are able to withstand more pressure Vein: lack muscular wall, more like a drain rather than a pump, thinner
What is the center of a blood vessel called? (central blood-containing space)
lumen
What are the three wall layers in arteries and veins? (inside to outside)
Tunica intima, tunica media, and tunica externa
The tunica media is _______ in an artery than in a vein
thicker
THe tunica externica is also known as __________
tunica adventida (nerves, lymphatic)
Elastic arteries don’t _____________
vasodilate or vasocontrict (because if they did, blood would pump back into the heart and/or blood wouldn’t have enough pressure to pump to the whole body)
Elastic arteries come from ___________ and contain __________
the heart (closest to the heart), elastin Elastic arteries are thick and large to accommodate for blood flow
Muscular arteries go to ______ and contain_______
organs, smooth muscle
Muscular arteries (can/cannot) vasoconstrict and vasodilate
can
Can arterioles vasoconstrict and vasodilate?
yes
What do capillaries do?
“exchange vessels” exchange O2 and pick up CO2
What is the equation for blood flow?
blood flow= ΔP/R (change in pressure over resistance)
What is the equation for cardiac output?
blood volume/minute
What is blood flow equal to?
BF=CO (blood flow=cardiac output)
When blood pressure increases, ____________ (on aorta) trigger vessels to ____________ to reduce blood pressure
baroreceptors, vasodilate
Capillaries are microscopic and have a _________ tunica intima, which allows ____________ to pass through
thin, only a single RBC to pass through at a time (single file)
What are pericytes? And what do they control?
cells that help stabilize capillary walls (form barriers), like insulation They control permeability, more pericytes less leakage
Capillaries provide direct access to __________________ and only have ______________
almost every cell, tunica intima
Capillaries exchange ____, ____, ____, between __________ and ______________.
gases, nutrients, wastes, hormones, etc, blood, and interstitial fluid
What are the three capillary types?
- Continuous (less openings, least permeable) 2. Fenestrated 3. Sinusoid (most permeable, most openings)
Identify each of the three capillaries
a) Continuous (least permeable)
b) Fenestrated
c) Sinusoid (most permeable)
What is microcirculation?
networks of capillaries between arterioles and venules
What do precapillary sphincters do?
regulare blood flow into true capillaries or to shunt
What is interstitial fluid?
The fluid the RBCs reside in (blood without RBCs)
When your body is hot and needs to cool down precapillary sphincters _______________ so blood can flow ____________
open, through true capillaries and cool down
When your body is cold and needs to warm up, precapillary sphincters __________ so that blood can flow _____________
close, through the metarteriole-throughfare channel and bypass true capillaries
Venules form when _____________
capillary beds unite
Venules are very ______ which allows ______ and _______ into tissues
porous, fluids and WBCs
Veins are formed when ____________
venules converge
Veins have _________ walls and ___________ lumens
thinner, larger
Blood pressure is __________ in veins than in arteries
lower
Veins are also called ____________ and contain up to ____________% of blood suppy
capacitance vessels, 65%
Veins don’t have __________ and _______ blood to heart
muscular walls, drains
Veins have ______ valves (unlike arteries)
one way valves
What are three vein adaptations that ensure blood return to the heart?
- Large diameter lumens 2. Venous valves 3. Venous sinuses (spaces)
What are three factors that aid in venous return?
- Muscular pump (skeletal muscle contraction “milks” blood toward heart) 2. Respiratory pump (breathing squeezes abdominal veins, which push blood toward heart, the diaphragm) 3. Venoconstriction (sympathetic NS, pushes blood toward heart)
What is blood flow?
volume of blood flowing through a vessel, organ, or entire circulation
What is blood pressure (BP)?
force per unit area exerted on wall of blood vessel by blood
What is resistance (peripheral resistance)?
opposition to flow, amount of fiction blood encounters with vessel walls
When resistance increases, blood flow ___________
decreases
Blood flow is _________ proportional to resistance
inversely (if R increases, blood flow decreases)
Blood flow is __________ proportional to blood pressure gradient (ΔP)
directly (if ΔP increases, blood flow increases/speeds up)
Where you would you find continuous capillaries?
skin, muscle, blood-brain barrier
Where would you find fenestrated capillaries?
Areas of active absorption or filtration, kidney or small intestine
Where would you find sinusoid capillaries?
liver, bone marrow, and spleen
Capillary beds are where networked of capillaries form between ____________ and ____________
arterioles and venules
When the sphincters are closed, blood only flows from the terminal arteriole (red) through the ____________ and ____________, then flows out of the postcapillary venule (blue)
Metaarteriole (red) and thoroughfare channel (blue)
What drains the capillary bed?
the postcapillary venule
What are the some short term ways to counteract fluctuations in blood pressure?
(by means of neural and hormonal controls)
altering resistance and CO by vasoconstriction or vasodilation, baroreceptors, epinephrine, and noepinephrine
How does your body counteract fluctuation in blood pressure long term?
direct or indirect renal regulation (which alters blood volume via urine output or retaining water)
