Chapter 21 - Blood Vessels and Circulation - REVIEW Flashcards
List the 5 general classes of blood vessels
arteries
arterioles
capillaries
venules
veins
a cross section of tissue shows several small, thin walled vessels with very little smooth muscle tissue in the tunica media. Which type of vessel are these”
these are VEINS
arteries and arterioles have a large amount of smooth muscle tissue in a thick, well developed tunica media
why are valves located in veins, but not in arteries?
in the arterial system, pressures are high enough to keep the blood moving forward.
In the venous system, blood pressure is too low to keep blood moving on towards the heart. Valves in veins prevent blood from flowing backward whenever the venous pressure drops
Where in the body would you find fenestrated capillaries?
fenestrated capillaries are located where fluids and small solutes move freely into and out of the blood, including endocrine glands, choroid plexus of the brain, abdorptive areas of the intestine, and filtration areas of the kidneys
identify the factors that contribute to total peripheral resistance
-vascular resistance (vessel length, diameter)
=blood viscosity
-turbulence
in a healthy individual, where is blood pressure greater: at the aorta or the inferior vena cava? explain
greater at the aorta
Blood moves along a pressure gradient from areas of high pressure to low pressure. If the pressure were higher in the inferior vena cava, blood would flow backward
While standing in the sun, Sally begins to feel light headed and faints. explain what happened
While a person stands for long periods of time, blood pools in the limbs which decreases venous return to the heart.
In turn, cardiac output decreases so less blood reaches the brain, causing fainting.
A hot day adds to this effect because of the loss of body water through sweating reduces blood volume
describe the action of vasodilators and local vasodilators
Vasodilators promote the dilation of precapillary sphincters
local vasodilators act at the tissue level to accelerate blood flow through their tissue of origin
How would applying slight pressure to the common carotid artery affect your heart rate?
Pressure on the carotid artery would decrease blood pressure at the baroreceptors in the carotid sinus.
This decrease would cause a decrease in action potentials
more sympathetic stimulations would be sent to the heart, resulting in an increase of heart rate
What effect would the vasoconstriction of the renal artery have on blood pressure and blood volume
Vasoconstriction of the renal artery would decrease both blood flow and blood pressure at the kidney.
In response, the kidney would increase the amount of renin it releases, which in turn would lead to an increase in the level of angiotensin 2.
this angiotensin 2 would bring about increased blood pressure and increase blood volume
Why does blood pressure increase during exercise?
- Cardiac output increases
- Resistance in visceral tissues increases
Name the immediate and long term problems related to the cardiovascular response to hemrrhoging
immediate problem during hemorrhaging is the maintenace of adequate blood pressure and peripheral blood flow
the long term problem is the restoration of normal blood volume
explain the role of aldosterone and ADH in long term regulation of blood volume
Both aldosterone and ADH (ant diuretic hormone) promote fluid retention and reabsorption at the kidneys, preventing further reductions in blood volume
identify the 2 circuits of the cardiovascular system
pulmonary circuit
systemic circuit
Identify the 3 major patterns of blood vessel organization seen in the pulmonary and systemic circuits of the cardiovascular system
- Peripheral distribution of arteries and veins in the body left and right sides are generally identical, except near the heart where the largest vessels connect to the atria or ventricles
- A single vessel may have several names as it crosses specific anatomical boundaries
- Tissues and organs are usually serviced by several arteries or veins
Trace the path of a drop of blood through the lungs, beginning at the right ventricle and ending at the left atrium
right ventricle->pulmonary trunk-> left and right pulmonary arteries->pulmonary arterioles->alveoli->pulmonary venules->pulmonary veins->left atrium
Why would compression of the common carotid arteries cause a person to lose consciousness
compression would reduce the blood pressure at the carotid sinus and cause a rapid reduction in blood flow to the brain, resulting in a loss of consciousness
An immediate reflexive increase in heart rate and blood pressure owuld follow
Identify the components of the cardiovascular system that are affected by age
blood, heart, blood vessels
Define thrombus
A thrombus is a stationary blood clot within the lumen of a blood vessel
Define aneurysm
an aneurysm is the ballooning out of a weakened arterial wall resulting from sudden pressure increases
Describe what the cardiovascular system provides for other body systems
provides other body systems with oxygen, hormones, nutrients, and white blood cells while removing carbon dioxide and metabolic wastes. it also transfers heat
What is the relationship between the skeletal system and the cardiovascular system
the skeletal system provides calcium needed for cardaic muscle contraction and protects developing blood cells in the bone marrow.
the cardiovascular system provides calcium and phosphate for bone deposition and transports parathyroid hormone and calcitonin to osteocalsts and blasts
Which blood vessels play the msot important role in regulating blood pressure and blood flow to a tissue?
arterioles
is cardiovascular function regulated by conscious control?
no
baroreceptors that function in the regulation of blood pressure are located…
in the carotid sinus
The 2 way exchange of substances between blood and body cells occurs only through…..
capillaries
large molecules such as peptides and proteins move into and out of the blood stream by way of….
fenestrated capillaries
The local control of blood flow due to the action of precapillary sphincters is due to the action of….
autoregulation
blood is transported through the venous system by means of….
muscular contractions and the respiratory pump
What is the most important factor in vascular resistance?
the diameter of the lumen of blood vessels
Net hydrostatic pressure forces water ____ of a capillary while osmotic pressure forces water ___ of a capillary
out of, into
What are the primary forces that cause fluid to move out of a capillary at the arterial end and into the interstitial fluid?
capillary hydrostatic pressure
What are the primary forces that cause fluid to move into a capillary from the venous end from the interstitial fluid?
blood colloid osmotic pressure
What cardiovascular changes occur at birth?
when an infant takes itd first birth, the lungs expand and the pulmonary vessels dilate.
increased venous return from the lungs
blood begins flowing through the pulmonary circuit.As pressure rises in the left atrium, the valvular flap closes the foramen ovale, completing the vascular remodeling
A major difference between the arterial and venous systems is that
in the limbs there is dual venous drainage
What would have the GREATEST effect on peripheral resistance
doubling the diameter of a vessel
Which is greater….
the osmotic pressure of the interstitial fluid during inflammation
the osmotic pressure of the interstitial fluid during normal conditions
the osmotic pressure of the interstitial fluid during inflammation
Relate the anatomical differences between arteries and veins to their functions
veins - thinner walls, greater diameter.
have valves
arteries - thicker walls, smaller diameter
more smooth muscle and elastic fibers, enabling them to resist and adjust to the pressure generated by the heart
-arteries constrict more than veins do when not expanded by blood pressure, due to a greater degree of elastic tissue
the endothelial lining of an artery has a pleated appearance because it cannot contract and so forms folds.
the lining of a vein looks like a typical endothelial layer
Why do capillaries permit the diffusion of materials, whereas arteries and veins do not?
Capillary walls are thin so distances for diffusion are short
continuous capillaries have small gaps between adjacent endothelial cells that permit the diffusion of water and small solutes into the surrounding interstitial fluid but prevent the loss of blood cells and plama proteins
fenestrated capillaries contain pores that permit very rapid exchange of fluids between interstitial fluids and plasma
the walls of arteries and veins are several layers thick and not specialized for diffusion
How is blood pressure maintained in veins to counter the force of gravity?
Contraction of surrounding skeletal muscles squeezes venous blood towards the heart (muscular pump) is assisted by valves which prevent the backflow of blood
the respiratory pump results from the increase in internal pressure of the thoracic cavity during exhalation pushes venous blood into the right atrium
How do pressure and resistance affect cardiac output and peripheral blood flow?
increased pressure = increased cardiac output and peripheral blood flow. Blood pressure is closely regulated by a combination of neural and hormonal mechanisms
the resistance of the vascular system opposes the movement of blood, so blood flow is inversely proportional to the resistance.
Sources of peripheral resistance = vascular resistance
viscosisty
turbulence
Why is blood flow to the brain relatively continuous and constant
the brain receives arterial blood via 4 arteries that form anastomoses with the cranium.
An interruption of any 1 vessel will not interrupt blood flow to the brain
compare the effects of the cardioaccelatory and cardioinhibitory centers on cardiac output and blood pressure
The cardioacceleratory and vasomotor centers are stimulated when general sympathetic activation occurs
the result is an increase in cardiac output and blood pressure
when the parasympathetic division is activated, the cardioinhibitory center is stimulated reducing cardiac output
Someone is outside on a very hot day sweating profusely.
Will their blood pressure be high or low
Fluid loss lowers blood volume, leading to sympathetic stimulation which elevates blood pressure
How do antihistamines increase blood pressure?
Antihistamines and decongestents are sympathomimetic drugs
stimulate the sympathetic nervous system
leads to increased heart rate, stroke volume, peripheral resistance
Standing up quickly causes light head and faint why
when standing up rapidly, gravity causes blood volume to move towards the lower parts of the body and away from the heart, decreasing venous return
