CH. 18/19 areas to work on Flashcards
Hypocalcemia _________ the heart
depresses
Hypercalcemia: _________ heart rate
increases
Hyperkalemia does what?
Alters electrical activity—leads to cardiac arrest
Hypokalemia does what?
Causes a feeble heart rate–arrhythmias
What is the normal, average cardiac output?
5.25 L/min
What is cardiac output?
Volume of blood pumped by each ventricle in one minute
What is stroke volume?
Volume of blood pumped by one ventricle with each beat
What is the maximal cardiac out put?
20-25 L/min (4-5 times the resting)
70mL/beat describes what?
average stroke volume
What is cardiac reserve?
Difference between resting and maximal CO
Heart rate can be increased via the sympathetic nervous system. How is this done?
Norepinephrine is released and binds to B1-adrenergic receptors. This causes pacemaker cells to fire rapidly.
Heart rate can be decreased via the autonomic nervous system. How is this done?
The parasympathetic nervous system opposes the sympathetic effects by using acetylcholine to hyperpolarize the pacemaker cells, slowing down the heart rate
When does the heart exhibit vagal tone?
At rest
Is the parasympathetic nervous system the dominant influence on heart rate?
Yes
Does cutting the vagal nerve increase or decrease the HR? What does it go up to?
Increase; around ~100
Is Tachycardia an abnormally fast or slow heart beat?
Fast ( > 100 beats/min)
Is Bradycardia an abnormally fast or slow heart rate?
Slow 60 beats/min
What layer of the tunica intima is found only in vessels larger than 1mm?
The subendothelial (connective tissue basement membrane)
Which layer is the bulkiest and responsible for maintaining blood flow and pressure?
Tunica media
The tunica _____ is innervated with sympathetic nerve fibers that control vasoconstriction and dilation
media
The tunica adventitia (externa) is made up of _____ fibers to protect and reinforce the wall and anchor it to surrounding structures
collagen
The tunica ______, like the tunica media, is also infiltrated with nerve fibers but also has _____ vessels on its surface
externa has lymphatic vessels
Are elastic arteries thick walled?
Yes
Are elastic aortas called distributing arteries?
No, they’re called conducting
Within elastic arteries, elastin is found in all three tunica but more is found in the tunica _____
media
Are elastic arteries inactive or active in vasoconstriction?
Inactive
Do the diameters of muscular arteries range from pinky-finger size to pencil-lead size?
Yes
Which type of arteries account for most of the named arteries?
Muscular
Which type of arteries have the thickest tunica media with more smooth muscle, but less elastic tissue?
Muscular
Even though muscular arteries have less of this, the tunica media is sandwiched between two _______ membranes
Elastic membranes
Are muscular arteries active or inactive in vasoconstriction?
Active
Arterioles are mostly a single layer of smooth muscle surrounding _________ cells
endothelial
Which arteries control flow into capillary beds via vasodilation and constriction of smooth muscle?
Arterioles
Arterioles are also called _______ arteries
resistance
Do pericytes control permeability and play a role in vessel repair?
Yes
Do pericytes supply almost every cell except for cartilage, capillaries, cornea, epithelia, and lens of the eye?
True except pericytes do supply capillaries
Which capillaries are abundant in muscles, lungs, and the CNS?
Continuous
Which type of capillaries are found in the kidneys and intestines?
Fenestrated
Are fenestrated capillaries found in areas that are active in endocrine hormone secretion?
Yes
Why are continuous capillaries of the brain unique?
They form the blood brain barrier and are totally enclosed via tight junctions and NO cellular clefts
Which type of capillaries are found in the liver, bone marrow, spleen, and adrenal medulla?
Sinusoidal
Do sinusoidal capillaries have complete basement membranes?
No, they’re incomplete
Which type of blood capillaries contain macrophages in the lining to capture and destroy foreign invaders?
Sinusoidal
Are vascular shunts channels that connect the arteriole directly with the venule?
Yes
What are true capillaries?
Actual vessels involved in exchange
True capillaries contain 10-1,000 vessels per capillary bed. T or F
False, 10-100
Capillaries don’t just unite into veins. What do capillaries unite to form before forming into veins?
Post capillary venules
Are post capillary very porous or impermeable?
Very porous
Veins have a thinner tunica _____ and a thicker tunica _____
thinner media; thicker externa
Veins are also called _______ vessels
capacitance vessels
65% of the body’s blood supply is found in the _____
veins
Are venous sinuses flattened veins with extremely thin walls?
Yes
Are venous sinuses composed of only loose reticular connective tissue?
No, they are composed of only endothelium
What is an example of a venous sinus in the body?
The coronary sinus of the heart
Are varicose veins painful and constricted due to incompetent valves?
No, they are painful and dilated
What are some examples of what causes varicose veins?
Straining to deliver a baby, being obese, or bowel movements that cause hemorrhoids from increased intra-abdominal pressure
What is the difference between vascular anastomoses and arterial?
Vascular anast. are simply interconnections of blood vessels. Arterial provide alternate pathways to ensure continuous flow even if one artery is blocked
What parts of the body are arterial anastomoses common?
Joints, abdominal organs, brain, and heart
Are arteriovenous anastomoses considered shunts in the capillaries? what is the other name?
Yes, metarteriole-thoroughfare channel
Venous anastomoses are so abundant that….
occluded veins rarely block blood flow because there are so many vessels the blood can be redirected to
Is peripheral resistance the opposition to flow?
Yes
What are the three important sources of resistance?
Blood viscosity, blood vessel length, and diameter.
What is atherosclerosis?
build up of fatty plaques in vessels that eventually cause the arteries to harden. Deadly in the elastic arteries.
Is laminar flow disrupted with abrupt changes in vessel diameter, causing the flow to become turbulent flow?
Yes
Is blood pressure near the heart considered pulsatile?
Yes
What are the two factors arterial blood pressure is determined by?
Elasticity and volume of blood forced into the arteries at any time
In which type of arteries does the steepest drop in pressure occur? Muscular or arterioles?
Arterioles
Does the pumping action of the lungs generate blood flow?
No, pumping action of heart
F = deltaP/R
The relationship between flow, pressure, and resistance (deltaP=pressure gradient)
Is diastolic pressure pressure exerted in aorta during the ventricular contraction?
No, that is systolic pressure
What is the average systolic pressure for adults?
120mmHg
Is Diastolic pressure the lowest level of aortic pressure when the heart is at rest?
Yes
What does MAP stand for?
Mean Arterial Pressure
Is MAP the pressure that propels blood to tissues?
Yes
Does the heart spend more time in diastole or systole?
Diastole
Are the three main factors for regulating blood pressure Cardiac Output, stoke volume, and peripheral resistance?
Regulating blood pressure involves Cardiac output, blood VOLUME, and peripheral resistance (not stroke volume)
What is the NFP equation? (think of the alphabet)
HPc + OPif ) - ( HPif + OPc)
Osmotic Pressure IF is in the _____ space and pulls fluid into or out of the capillary?
interstitial space; out of capillary
Do all vessels constrict except for the ones by the heart and brain if blood volume drops?
Yes (relates to MAP which is maintained by altering blood vessel diameter, which alters resistance)
Where are the baroreceptor reflexes located? (think upper body)
carotid sinuses, aortic arch, and walls of large arteries
If MAP is high, are your baroreceptors stimulated or inhibited?
Sti
Does Atrial Natriuretic peptide increase or decrease BP by antagonizing aldosterone?
Decrease BP
Does ADH increase or decrease BP?
Increase
Does Hypovolemic shock result from blood loss or extreme vasodilation?
Extreme blood loss
Does vascular shock result from an inefficient heart or extreme vasodilation and decreased peripheral resistance?
Extreme vasodilation and decreased PR.
Does cardiogenic shock occur when an inefficient heart cannot sustain adequate circulation?
Yes
Vasomotion is the intermittent flow of blood through the capillaries. T or F?
True
Explain HPc
Hydrostatic pressure in the capillary will push fluid out of the capillary.
Explain HPif
Hydrostatic pressure in the interstitial fluid will PUSH fluid into the capillary
Explain OPc
Osmotic pressure in the capillary pulls/sucks fluid into the capillary
Explain OPif
Osmotic pressure in the interstitial fluid pulls/suck fluid out of the capillary
A positive NFP is indication of reabsorption or filtration?
filtration
A negative NFP is indication of filtration or reabsorption?
Reabsorption
What happens when an NFP is positive?
Fluid moves from the capillary into the interstitial space (filtration) (at arteriole end)
what happens when an NFP is negative?
Fluid moves from the interstitial space into the capillary (reabsorption) (at venous end)
Is Opc ~26mm Hg?
Yes
Is OPif around 10 mm Hg?
No, around 1
Is HPc at the arterial end around 35mm Hg?
Yes
Is HPc at the venous end lower or higher than at the arterial end?
Lower, around 17 mm Hg
Which pressure system is usually at 0mm hg?
HPif
Can a decrease in OPc be caused by Hypopoteinemia? (low levels of plasma protein)
Yes
An increase in HPif can be caused by edema. Think this through. Does it make sense?
Yes….edema is an increase in interstitial fluid. HPif is the hydrostatic pressure in the interstitial space.
