57 terms

A & P Lecture #4 Study Guide- Blood Vessels

Name the order of blood vessels starting and ending at the heart
back to heart
What are the 3 layers of an artery/vein
Tunica interna, Tunica media, & Tunica externa
How many layers does a capillary have
Only 1, Tunica interna
What are the key characteristics of arteries
Carry blood away from the heart, attached to ventricles,contain smooth muscle & elastic tissue
What are the 3 types of arteries
Elastic, Muscular, & Arterioles
What type of artery would the aorta be classified as
Elastic, largest and able to withstand really high blood pressure
What is the smallest artery
What artery distributes blood to the organs
Muscular artery
What is an example of a muscular artery
Renal artery
What are the characteristics of veins
carry blood from all tissues & return to the r & l atrium, thinner walls than arteries, contain valves in their walls, contain 65% of body's blood
What is the smallest vein
Venules ( collecting)
Is the tunica media of a vein thinner or thicker than an artery, explain
Thinner, blood pressure is lower so they do not need as much smooth muscle
What type of vessel contains the most blood
What percent of blood do veins contain
What is the function of valves in veins
To make sure that the blood doesn't flow backwards
Where in the body do veins CONTAIN valves
Upper & lower limbs, neck/head
Where in the body do veins NOT contain valves
Thoracic & Abdominal cavities
Name the 2 mechanisms for venous return
Muscular Compression pump, Respiratory pump
What happens when valves in the veins weaken
blood tends to pool in the veins leading to varicose veins or hemorrhoids
What does the muscular compression pump do
contractions of skeletal muscles help push blood toward the heart, occurs during normal movement, walking
What is the only blood vessel whose walls permit the exchange of materials
What is a continuous capillary
Do not have pores , permit exchange of smaller substances
What substance passes through a continuous capillary
Water, ions
What is a fenestrated capillary
Contain pores
What substance passes through a sinusoid capillary
What is a siusoid
Contain large pores, permit exchange of larger materials
Where are the pores in continuous & fenestrated capillaries
Tunica interna
How does the blood flow through a capillary bed
Bands of smooth muscle at the entrance of capillaries, precapillary sphincters alternately contract & relax, as a result blood flow occurs in pulses .
What is vasomotion
Cycling of contraction & relaxation of smooth muscle that changes blood flow thru capillary beds
What is a Metarteriole
Vessel at the beginning of capillary bed, contains precapillary sphincter
What is a precapillary sphincter
Band of smooth muscle that controls blood flow thru a capillary bed
What is Thoroughfare channel
Capillary connecting the metarteriole to the venule
What is the direct connection of an arteriole & venule known as
Arteriovenous anastomoses
What does an arteriovenous anastomoses bypass
Capillary bed
Define blood circulation
Related to blood pressure & the resistance in the vessels
Define pressure
The greater the pressure is within a blood vessel, the faster the blood flows
What is the blood circulation formula
Blood flow is proportional to pressure gradient divided by resistance
What are the different types of pressures that exist within blood vessels
Arterial, Capillary Hydrostatic pressure(CHP) & venous
Which pressure in the blood vessels is the highest
Arterial blood pressure,blood flows the fastest
Which pressure is the lowest in blood vessels
Venous, blood flows the slowest
What blood vessel does blood flow medium
CHP- capillary hydrostatic pressure
Define resistance
The LOWER the resistance, the faster the blood flows
What are the types of resistance that exist in blood vessels
Vascular resistance, Viscosity, & Turbulence
What is vascular resistance
How much friction exists between the blood & walls of the blood vessels
What is Viscosity
How "thick & syrupy" a fluid is
What is Turbulence
How "smooth" the blood flow
If a vessel is more viscous do you have more or less resistance,
More resistance
What does More viscous & More resistance do to blood flow
Slower blood flow
If a vessel is less viscous and less resistance
what happen to blood flow
Faster blood flow
More turbulence= more resistance= what kind of blood flow
Slower blood flow
Less turbulence=Less resistance= what kind of blood flow
Faster blood flow
Define pulmonary circuit
Consists of vessels that carry blood FROM the heart, TO the lungs, and BACK TO the heart.
Does the right or left ventricle pump into the pulmonary trunk
right ventricle
Do the pulmonary arteries contain oxygenated or deoxygeneated blood
During gas exchange, does oxygen move into or out of the blood
Into the blood
What gas moves out of the blood during gas exchange
Carbon dioxide
Which blood vessels return the blood from the lungs to the left atrium
Right & Left pulmonary veins