Save
Busy. Please wait.
Log in with Clever
or

show password
Forgot Password?

Don't have an account?  Sign up 
Sign up using Clever
or

Username is available taken
show password

Your email address is only used to allow you to reset your password. See our Privacy Policy and Terms of Service.


Already a StudyStack user? Log In

Reset Password
Enter the associated with your account, and we'll email you a link to reset your password.

Question

Blood vessels contain 3 layers
click to flip
focusNode
Didn't know it?
click below
 
Knew it?
click below
Don't know

Question

Tunica interna is in direct contact with
Remaining cards (244)
Know
0:00
Embed Code - If you would like this activity on your web page, copy the script below and paste it into your web page.

  Normal Size     Small Size show me how

--- SP Blood Vessel

Exam #2

QuestionAnswer
Blood vessels contain 3 layers 1. Tunica externa 2. Tunica media 3. Tunica interna
Tunica interna is in direct contact with blood flow
lumen opening
Elastic or conducting arteries are found closest to the heart
Capillaries usually connect arterioles and venules
Capillaries branch to form extensive networks
Flow of blood through a network is regulated by smooth muscle
CAPILLARY EXCHANGE KNOW THE U-SHAPED TUBE AND WHAT GOES ON - LOOK AT NOTES
Elastic or conducting arteries are found closest to the heart
Capillaries usually connect arterioles and venules
Capillaries branch to form extensive networks
Flow of blood through a network is regulated by smooth muscle
CAPILLARY EXCHANGE KNOW THE U-SHAPED TUBE AND WHAT GOES ON - LOOK AT NOTES
Vein shape and thickness compared to arteries Thinner : farther away from the heart. Cannot maintain shape, sometimes collapses
Venules drain capillary blood and return blood to the heart
Smallest venules are located closest to the capillaries
Venules have __ junctions loosely organized junctions
Venules function as the site for exchange of nutrients, wastes, movement of white blood cells from bloodstream -> inflammed/infected tissue
As venules grow larger their walls thicken and lose the ability to exchange with interstitial fluid
Venules are group of capillaries within a tissue that reunite to form small vessels
Veins are blood vessels that carry blood from tissue back to the heart
Vein ratio of wall thickness to diameter wall thickness
Tunica interna is made up of two layers 1. endothelium (inner) 2. interal elastic lamina (outside)
Endothelium of interna lines the inner surface of cardiovascular, influences blood flow, secreting chemical mediators that affect vessel contraction, capillary permeability
Internal elastic lamina function facilitates diffusion through tunica interna to media
Internal elastic lamina looks like swiss cheese
Endothelium of interna is composed of which cells simple squaimous
Deep inside the endothelium of the interna is the __ membrane basement
basememnt membrane function anchors endothelium to tissue, supports base for tensile strength and resilience for stretch + recoil
Tunica media description and composed of thick layer, composed of smooth muscle cells/elastic fibers.
Where are smooth muscle cells found in the 3 layers tunica media
Primary function of smooth muscle cells encircles lumen like ring on finger, regulates diameter of lumen
The regulation of the diameter of lumen is important for influencing blood flow and pressure
Tunica externa composed of elastic/collagen fibers
External Elastic Lamina function separates the tunica externa from tunica media, anchors vessel to surrounding tissues
External externa contains nerves that supply tissue of vessel walls
Arteries carry blood away from the heart
What layer is significantly different in arteries tunica media
What supplies smooth muscle of arteries sympathetic ganglionic axons of ANS
An increase in ANS stimulation -> contraction of smooth muscle of arteries
A contraction has what affect on the lumen narrowing of lumen and squeezing the arterial wall
Vasoconstriction Decrease in diameter of the lumen
A decrease in ANS stimulation -> relaxation of smooth muscle of arteries
A relaxation has what affect on the lumen Lumen is more open and no pressure on arterial wall
Vasodilation Increase in diameter of the lumen
Vasospasm occurs when an artery or arteriole is damaged
Vasospasm limits blood flow through the damaged vessel wall and helps reduce blood loss if the vessel is small
Elastic arteries are the largest diameter arteries in the body
How are elastic arteries characterized thick tunica media dominated by elastic fibers
Elastic artery function propel blood onward while the ventricles are relaxing
As blood is ejected from heart into elastic arteries, their walls stretch easily to accommodate the pressure from the blood
Pressure reservoir As elastic fibers stretch, they momentarily store mechanical energy
How do elastic articles propel blood and when When ventricles are relaxed, the arteries recoil
Elastic arteries are also called ___ because conducting arteries, because they conduct blood from heart to muscular arteries
muscular arteries are (size-wise) medium-sized
Tunica media of muscular arteries contain more smooth muscle and fewer elastic fibers (which makes their walls really thick)
Because the tunica media of muscular arteries is thick it is capable of greater vasoconstriction + vasodilation
Elastic artery wall compared to diameter 10% of vessel's total diameter AA
Muscular artery wall compared to diamter 25% of vessel's total diameter AA
Muscular arteries are also called ___ because distributing arteries because they distribute blood to organs
Anastamoses is a Union of branches of two or more ARTERIES that supply the same body region
Anastomoses provide alternative routes for blood to reach a tissue or organ
Collateral circulation the alternative circulatory route of blood flow to a body part through anastomoses
Arteries that do not anastomoses are called end arteries
Obstruction of an end artery leads to necrosis of that segment
necrosis death
Arterioles Small arteries
Elastic arteries -> muscular arteries - > arterioles -> capillaries
Conducting arteries -> distributing arteries -> arterioles -> capillaries
Size of arterioles microscopic
Function of arterioles Regulates the flow of blood into capillary networks (which conntrols SVR since it regulates diameter)
Terminal end of arteriole is called metartieriole
Metarterioles narrow towards capillary junctions
What happens at metarteriole-capillary junction the muscle cell farthest away forms the precapillary sphincter
precapillary sphincter function monitors the blood flow into the capillary
What layer of the arteriole contains the sympathetic nerves Externa
Key role of arterioles Regulates blood flow from arteries to capillaries by regulating resistance
Resistance opposition to blood flow
Resistance is mainly due to the friction that occurs between blood + inner walls of blood vessel
The smaller the blood vessel, the ___ the resistance the greater
Contraction -> vaso____ -> ? resistance -> ? blood flow constriction, higher, lower
Relaxation -> vaso____ -> ? resistance -> ? blood flow lower, higher
Vasoconstriction causes ? blood pressure higher
Vasodilation causes ? blood pressure lower
Capillaries are the smallest of blood vessels
Capillary connect arterial outflow from heart to venous return
Primary function of capillary exchange of substances between blood and interstitial fluid
Tissues with lower metabollic activity contain fewer capillaries
Capillaries are absent in cornea, lens, and cartilage
Capillaries lack the layers tunica media and tunica externa
capillary walls are composed 1 layer of endothelial cells and a basement membrane
Exchange of materials occur ONLY through walls of capillaries and beginning of venules
Exchange cannot happen anywhere else because their layers are too thick
Capillary bed a network of 10-100 capillaries that arise from a single metarteriole
Blood can flow through capillary network from an arteriole into a venule by 1. capillaries 2. thoroughfare channel
1. Capillary flow blood -> arteriole -> capillary -> venules
Junction present in between metaarteriole and capillaries are precapillary sphincters
When precapillary sphincters are relaxed blood flows into capillaries
when precapillary sphincters are contracted blood flow is decreased or stopped
2. Thoroughfare channel Provides direct route for blood to go from arteriole to venule BYPASSES capillary
Autoregulation The ability of a tissue to automatically adjust its blood flow to meet metabollic demands
Three types of capillaries 1. Continuous 2. Fennestrated 3. Sinusoids
Continuous capillaries Endothelial cells, separated only by intercellular clefts.
Intercellular clefts prevent substances from diffusing
Intercellular clefts are found in the brain
Blood brain barrier contains continuous capillaries
Fenestrated capillaries contain many small holes
holes of fenestrated capillaries allow greater exchange of materials
Fenestrated capillaries are found in kidneys, where filtration occurs
Sinusoids contain large holes, incomplete/absent membrane and large intercellular clefts
Large holes of sinusoids are so leaky that large molecules and blood cells can pass through as well
Portal system Blood passes from one capillary network to another through a vein
Mission of the entire cardiovascular system is to keep blood flowing through capillaries and allow capillary exchange
At any given time ___% of blood is continually exchanging materials 7%
Most capillary exchange occur through the process of simple diffusion
Water-soluble substances diffuse across capillary walls through intercellular clefts or fenestrations
Lipid soluble substances diffuse through lipid bi-layer
What cannot pass through capillary walls of continuous and fenestrated plasma proteins, red blood cells
Transcytosis When substances are enclosed in pinocytic vessicles that first enter via endocytosis, then move across the cell and exit on other side via exocytosis
Transcytosis is mainly for substances that are large, lipid-soluble or other substances that cannot cross capillary wall
Whether fluid leaves or enters the cell depends on balance of pressure
filtration when pressure that push fluid out of capillary exceeds the pull of fluid into capillary
reabsorbtion when pressure that pulls fluid into capillary exceeds fluid that pushes fluid out of capillary
vein layers compared to arteries tunica interna and tunica media are much thinner
Veins lack external and internal elastic laminae
Because veins lack external and internal elastic laminae they can stretch, but are not structured to withstand high pressure
Lumen of vein compared to artery larger
Why do veins look flat very thin walls
Average blood pressure in veins compared to arteries considerably lower
Speed of blood flow in veins slow, steady
Speed of blood flow in arteries rapid
What do veins contain that arteries do not valves
Valves are Thin folds of tunica interna that form flaplike cusps
Valve function prevents backflow of blood
The low blood pressure of veins allows blood flow to be slow, and tend to try to back up
Venous sinus vein within endothelium wall that has no smooth muscle to alter its diameter
What is replaced in venous sinus surrounding dense connective tissue replaces tunica media and tunica externa in providing protection
Venous return the volume of blood that flows back into the heart via systemic veins
Venous return is generally assisted by contraction of heart muscle
Blood pressure is measured in mm Hg
Venous sinus quoted in notes flattened veins with thin walls (only endothelium)
problems with venous return pressure pushing blood up is barely enough to overcome gravity
Two mechanisms that assist venous return 1. skeletal muscle pump 2. respiratory pump
Skeletal muscle pump steps. 1. At rest- valves are open 2. Contraction of muscles- milking 3. Relaxation of muscles- valves closer to heart close, farther from heart opens because pressure in foot is higher than in leg
Respiratory pump 1. Inhaling- abdominal veins compressed, blood moves from abdominal into thoracic veins into atria. 2. exhalation- valves prevent backflow of blood from thoracic into abdominal
Largest portion of your blood is at rest
Largest portion of your blood is located in systemic veins and venules
Systemic arteries hold about __% of blood 13% of blood
pulmonary blood vessels hold about _% of blood 9%
Capillaries hold about _% of blood 7
heart chamber holds about _% of blood 7
because systemic veins and venules contain a large % of blood volume they function as blood reservoirs
blood from blood reservoirs can be diverted quickly if needed
Principal blood reservoirs are the veins of abdominal organs, and skin
Blood flow is the volume blood that flows through any tissue in a given time
Blood flow is measured in mL/min
Total blood flow is equal to cardiac output
Cardiac output is the volume of blood that circulates through blood vessels each minute
Cardiac output depends on heart rate and stroke volume
How cardiac output is distributed depends on 2 factors 1. pressure difference that drives blood flow into tissue 2. resistance to blood flow
Blood flows from ___ to ___, meaning that the greater the pressure difference, ___ higher, lower the greater the blood flow
Blood pressure pressure exerted by blood on walls of blood vessel
Blood pressure is generated by the contraction of ventricles
Blood pressure is HIGHEST in aorta and large systemic arteries
Average blood pressure 120/80
what are the numbers 120/80 stand for 120 = systole 80 = diastole
Systolic blood pressure is the highest blood pressure attained in arteries during systole
diastolic blood pressure is the lowest arterial blood pressure attained during diastole
resistance is frequently referred to as peripheral resistance
blood viscosity thickness of blood, stickiness
As distance increases between the heart and blood vessel, the blood pressure becomes lower
Total blood less than 5 L tend to lower blood pressure
Total blood more than 5L tend to increase blood pressure
Vascular resistance opposition of blood flow due to friction between blood and the wall
Vascular resistance depends on 3 things 1. Size of lumen 2. Blood viscosity 3. Total blood vessel length
1. Size of lumen The smaller the size of the lumen, the greater the resistance is to blood flow
2. Blood viscosity The higher the blood viscosity, the higher resistance
Blood viscosity is the ratio of red blood cells to plasma
Conditions that increases blood viscosity dehydration and polycythemia
Conditions that decrease blood viscosity loss of plasma proteins, anemia, hemmorrhage
3. Total blood vessel length Resistance to blood flow length is directly proportional to length of blood vessel
Systemic vascular resistance is also known as total peripheral resistance
systemic vascular resistance refers to all vascular resistances offered by systemic blood vessels
Resistance in large blood vessels compared to small blood vessels smaller
Cardiovascular center is located in the medulla oblongata
Cardiovascular center helps regulate heart rate and stroke volume
Cardiovascular center controls neural and hormonal negative feedback systems that regulate blood flow to specific tissues
Cardiovascular center receives input from both higher brain regions and sensory receptors
Nerve impulses descend from ____ in order to cerebral cortex, limbic system, and hypothalamus affect the cardiovascular center
Three main types of sensory receptors that provide input to the cardiovascular center are 1. proprioceptors 2. baroreceptors 3. chemoreceptors
Proprioceptors monitor movements of joints and muscles
Proprioreceptors send impulse to cardiovascular center during physical activity
Proprioreceptors input to the cardiovascular center accounts for rapid increase in heart rate (exercise)
barroreceptors monitor changes in pressure and stretch in walls of blood vessels
chemoreceptors monitor concentration of various chemicals in blood
Output from the cardiovascular center flows along sympathetic and parasympathetic neurons of ANS
Opposing sympathetic and parasympathetic function influences control of the heart
Output from cardiovascular center sends impulses to smooth muscle in blood vessel wall through the body via vasomotor nerves
vasomotor nerves how output from cardiovascular center sends impulses to smooth muscle in blood vessel wall
vasomotor tone moderate state of vasoconstriction due to impulse from cardiovascular center to smooth muscle in blood vessel wall
Sympathetic stimulation of most veins result in constriction and movement of blood out of venous blood resevoirs
Nervous system regulates blood pressure via two types of reflexes 1. baroreceptor reflex 2. chemoreceptor reflex
baroreceptor reflex are located in the aorta, carotid, and large arteries
When blood pressure falls, the baroreceptors send are stretched less and send impulses at slower rate, which results in decrease in parasympathetic stimulation
When increase in blood pressure, baroreceptors send send impulses at faster rate, and increases parasympathetic stimulation
Chemoreceptor reflexes are located close to baroreceptors in structures called carotid bodies and aortic bodies
Examples of what chemoreceptors would detect hypoxia acidosis hypercapnia
hypoxia low O2
acidosis increase in H+
hypercapnia excess CO2
Hormones that regulate blood pressure 1. renin-angiotensin-aldosterone system 2. epinephrine and norepinephrine 3. ADH 4. atrial natriuretic peptide
Renin-angiotensin-aldosterone system detects when blood volume to the kidneys is low
Renin-angiotensin-aldosterone system steps 1. renin + angiotensin-converting enzyme -> angiotensin II
angiotensin II ____ blood pressure raises by 1. causing vasoconstriction 2. secretes aldosterone
aldosterone function reabsorbs Na and water
Epinephrine and norepinephrine affect on blood pressure increase rate and force of heart contractions, vasodilate arteries in skeletal muscle to increase blood flow
ADH affect on blood pressure prevents dehydration and decreased blood volume, vasoconstricts.
Atrial natriuretic peptide affect on blood pressure lowers blood pressure by causing vasodilation and promoting the loss of salt and water in urine
ADH and atrial natriuretic peptides are OPPOSITE EFFECTS
Pulse Traveling pressure wave
How is pulse created the alternate expansion and recoil of elastic arteries after each contraction of the left ventricle
Pulse is strongest in the arteries closest to the heart
Pulse is weakest in arterioles
Pulse disappears in capillaries
Pulse may be felt in any artery that lies near the surface of the body
Common pulse points are 1. Superficial temporal artery 2. Facial artery 3. Common carotid artery 4. brachial artery 5. Radial artery 6. Femoral artery 7. Popliteal artery 8. Dorsal artery
Pulse is generally the same as heart rate
Normal pulse is 70-80 bpm
Tachycardia rapid resting heart rate that is 100+ bpm
Bradycardia slow resting heart rate that is less than 50 bpm
Blood pressure is measured by a device called sphygmomanometer
sphygmomanometer consists of rubber cuff connected to a rubber bulb that is used to inflate the cuff and a meter used to register the pressure in the cuff
Process of taking blood pressure 1. Inflating enough pressure to close the artery 2. First sound that is hurt is when the artery is opened enough to allow blood to flow through (systolic pressure) 3. when the sound stops it is called diastolic pressure
The sounds heard while taking blood pressure is called Korotkoff sounds
Pulse pressure is the difference between systolic and diastolic pressure
Pulse pressure value is normally 40 mm Hg
atherosclerosis condition that greatly increases pulse pressure
Circulatory routes routes that the body is organized to carry blood to specific organs
The two main circulatory routes are pulmonary and systemic
colloid pressure pressure that pulls fluid into capillary
capillary blood pressure pressure that pushes out of the capillary
Cardiovascular center sends impulses to smooth muscle via vasomotor nerves
baroreceptors located in aorta
chemoreceptors located in carotid bodies next to baroreceptors
blood pressure is clinically defined as pressure that is exerted in the left ventricle during systole and pressure remaining in arteries during diastole
Created by: 513143331
 

 



Voices

Use these flashcards to help memorize information. Look at the large card and try to recall what is on the other side. Then click the card to flip it. If you knew the answer, click the green Know box. Otherwise, click the red Don't know box.

When you've placed seven or more cards in the Don't know box, click "retry" to try those cards again.

If you've accidentally put the card in the wrong box, just click on the card to take it out of the box.

You can also use your keyboard to move the cards as follows:

If you are logged in to your account, this website will remember which cards you know and don't know so that they are in the same box the next time you log in.

When you need a break, try one of the other activities listed below the flashcards like Matching, Snowman, or Hungry Bug. Although it may feel like you're playing a game, your brain is still making more connections with the information to help you out.

To see how well you know the information, try the Quiz or Test activity.

Pass complete!
"Know" box contains:
Time elapsed:
Retries:
restart all cards