Download Peripheral lab answers

Anatomy & Physiology I
Peripheral Vascular System
1. Arteries & Veins
a) Arteries are high or low pressure vessels (circle correct answer).
b) Arteries always carry blood away from the heart. True or False
c) Veins always carry deoxygenated blood. True or False
2. Varicose veins
a) What are varicose veins?
-twisted, dilated superficial veins
b) What causes varicose veins?
-by leaky venous valves, stressed from prolonged standing or pregnancy
c) What happens to the blood when varicose veins occur?
-allow backflow and pooling of blood, extra pressure forces fluids into surrounding
tissues, nearby tissue is inflamed and tender
3. Hemodynamics
(velocity of blood flow)
a) What is the velocity of blood flow?
-speed of blood flow in cm/sec is inversely related to cross-sectional area
-slow rate in capillaries allows for exchange
b) What is circulation time?
-is time it takes a drop of blood to travel from right atrium back to right atrium
(volume of blood flow)
a) What is cardiac output?
- =stroke volume x heart rate
b) Name 2 factors that influence cardiac output.
-blood pressure, resistance due to friction between blood cells and blood vessel walls
(blood pressure)
a) What is blood pressure & what causes it?
-pressure exerted by blood on walls of a vessel - caused by- contraction of the
ventricles
ie.- 120mmHg during systole & 80 during diastole
b) If heart rate increases cardiac output does blood pressure rise or fall?
c) Does pressure fall or rise in systemic circulation with distance from left ventricle?
d) How much does blood volume have to decrease for blood pressure to drop?
-10%
e) Does water retention increase or decrease blood pressure
(resistance)
a) What is resistance?
-friction between blood and the walls of vessels
b) What are 3 variables that affect resistance?
_average blood vessel radius___- smaller vessels offer more resistance to blood flow
_blood viscosity (thickness)____- ratio red blood cells to plasma volume, increases in
viscosity increases resistance, ie- dehydration
_total blood vessel length______- the greater the resistance to flow, 200 miles of
blood vessels for every pound of fat, ie-obesity causes high blood pressure
c) The 3 variables above make what?
-systemic vascular resistance is the total of above
d) How do arterioles control blood pressure?
-arterioles control BP by changing diameter
(venous return)
a) What is venous return?
-volume of blood flowing back to the heart from the systemic veins
b) Venous return depends on _pressure___________ difference from venules
(16mmHg) to right atrium (0mmHg)
c) If tricuspid valve is leaky will it cause a build up or loss of blood on venous side
of circulation?
d) What is a skeletal muscle pump?
-contraction of muscles & presence of valves
e) What is a respiratory pump?
-decreased thoracic pressure and increased abdominal pressure during inhalation
-moves blood into thoracic veins and the right atrium
4. Syncope
a) What is syncope?
-fainting or a sudden, temporary loss of consciousness not due to trauma, due to
lack of blood flow to the brain
b) What are 4 causes of syncope?
vasodepressor syncope=sudden emotional stress
situational syncope=pressure stress of coughing, defecation, or urination
drug-induced syncope=antihypertensives, diuretics, vasodilators and tranquilizers
orthostatic hypotension=decrease in BP upon standing
5. Input to the Cardiovascular Centre – Match the appropriate definitions with the
correct #.
1-higher brain centres
2-proprioceptors
3-barorceptors
4-chemoreceptors
_2_____input during physical activity
_1_____anticipation of competition, increase in body temperature
_4_____monitor concentration of chemicals in the blood
_3_____changes in pressure within blood vessels
6. What does a carotid sinus massage have to do with syncope?
-anything that puts pressure on carotid sinus
-tight collar or hyperextension of the neck, may slow heart rate & cause carotid
sinus syncope or fainting
7. What is shock and how does it affect homeostasis?
-shock is failure of cardiovascular system to deliver enough O2 and nutrients
-cells forced to switch to anaerobic respiration, lactic acid builds up, cells & tissues
become damaged & die
8. Pulse points-label the specific diagrams with the correct name
a)
b)
superficial temporal
______________________________
c)
facial
______________________________
e)
common carotid
______________________________
g)
brachial
______________________________
femoral
_______________________________
d)
popliteal
_______________________________
f)
radial
_______________________________
h)
dorsal pedis
_______________________________
9. Which arteries branch off the aorta to supply the heart muscle?
-right and left coronary arteries branch to supply heart muscle
10. Venipuncture
a) Where is venipuncture normally performed in adults?
-cubital fossa, dorsum of the hand
b) Where is it performed in infants?
-great saphenous vein in infants
11. Label the following diagrams and use the answer key on the back page to check
your answers.
-see answer key provided
Arteries of the Brain
 arterial shunts called the
communicating arteries
connect the posterior cerebral arteries and the middle cerebral arteries. There
are two (2), a right and a left.
 An anterior communicating artery (only 1), joins the right and left anterior
cerebral arteries
 Together these vessels form an arterial anastomosis called the ____Circle of
Willis_________________
 An anastomosis functions to provide alternate routes for blood to reach an
area if an occlusion occurs. (ie blood clot)
Hemostasis:
What are three steps in vascular hemostasis:
1. vascular spasm
2. formation of platelet plug
3. blood clotting (cascade)
What is the difference between the intrinsic and extrinsic pathway?
Started by tissue trauma = Extrinsic pathway and has fewer steps and is fast
Started by blood trauma= intrinsic pathway and is more complex and is slow
How (in general) are the various clotting factors activated?
Inactive factor plus Ca ions active to form an active clotting factor
What is the steps in the common pathway?
Prothrombin plus Ca and activated X convert to Thrombin
Thrombin plus Ca covers Fibrinogen to Fibrin in the presence of Ca
Fibrin threads tighten and form the clot
What is the function of fibrin in the clotting process?
Fibrin forms the threads that make up the matrix of the clot
What is clotting time and how is it measured?
The time it takes after some kind of injury for the fibrin threads to be produced in
blood (can be measured when blood is drawn and observed for time (in secs) before
a visable clot occurs. Normally about 25-40 secs. Anticoagulants increase this. The
measured value is PTT or PT
Autoregulation
1. How is blood direction controlled through the capillary beds?
Through precapillary sphinctors
2. Which chemicals affect the arterioles and precapillary sphincters.
H+ /Co2 and O2 levels are the primary ones
Capillary Exchange
1. Draw a diagram outlining the filtration and reabsorption at the arterial and venous end
of the capillary bed. Include the rough hydrostatic and colloid osmotic pressures at each
end and what the net filtration would be:
See diagram 21.7 in your book
2. What takes care of the left over fluid that is not absorbed?
Lymphatic system
3. What is the role of plasma proteins in the process of filtration? What would happen if
the colloid osmotic pressure is much less in the blood?
They provide the “pull” of the BCOP= blood colloid oncotic or osmotic pressure. If
there were less, there would be more for the lymphatic system to pick up as less
would be absorbed on the venous end of the capillary bed
4. What is Starlings Law of the Capillary?
That under normal circumstances there is a net equilibrium between the arterial
and venous ends as the volume of fluids and solutes on both ends balance