Download Review Questions: Short Answer ANSWERS File

Circulatory System Short Answer Review ANSWERS
1.
What is the major (largest) artery of the body? aorta What is the major vein of the body? Vena cava
(superior and inferior)
2.
What is the pericardium? Double membranous sac that surrounds the heart
3.
What is myocardium? The muscle tissue that makes up the heart
4.
What is the septum? The tissue that separates the left and right side of the heart
5.
Explain the electrical cardiac cycle. Medulla oblongata sends message to heart, SA node (pacemaker) in
wall of right atrium receives message and causes both atria to contract. AV node at base of right atrium is
stimulated by pacemaker and send message along purkinje fibres (nerve fibres within myocardium that surround
each ventricle) and cause muscular tissue around ventricles to contract. The entire heart rests.
6.
Explain the 4 valves of the heart. What is their function, structure, and location. Right atrium – upper right
chamber that receives oxygen-poor blood from the vena cava and pumps blood to the right ventricle. Right
ventricle (lower right chamber) pumps blood out the pulmonary truck/artery (to the lungs). Left atrium (upper left
chamber) receives oxygen-rich blood from the pulmonary veins (from the lungs) and pumps blood to the left
ventricle. Left ventricle (lower left chamber) has the thickest myocardium and pumps blood out of the heart via
the aorta (to body tissues)
7.
What are chordae tendineae? Fibrous strands that attached to the AV valves and the ventricles to
prevent the ventricle from inverting
8.
Explain how the autonomic nervous system regulates the heartbeat. (parasympathetic and sympathetic)
parasympathetic nervous system stimulation decrease heart rate (normally active at rest) whereas the
sympathetic nervous system increases heart rate (response to stress)
9.
What is blood pressure? Pressure of blood against vessel walls created by beating heart What is systolic
pressure? Highest arterial pressure What is diastolic pressure? Lowest arterial pressure (ventricle relaxing; atria
contracting)
10.
Explain how blood pressure changes as the blood moves throughout the body. Highest at aorta, falls
through arteries, very, very low in capillaries and remains low in veins
11.
Explain the factors that affect blood pressure. Vasoconstriction increases BP & vasodilation lowers BP,
Blood viscosity (thick blood increased BP whereas thin blood with lots of water lowers BP), cholesterol build-up
(arteriosclerosis) and reduced vessel elasticity (atherosclerosis) increase BP, the amount of blood (blood volume)
affects BP (less volume lowers BP whereas increased volume usually due to high salt diet increases BP),
increased heart rate increased BP whereas low heart rate reduces BP, age (less elasticity of vessels) increases BP
as well as increased stress can increase BP.
12.
Differentiate between vasoconstriction and vasodilation. Vasoconstriction is the decrease in diameter of
the blood vessel which increased BP. Vasodilation is the increase in diameter, which lowers BP.
13.
Differentiate between hypotension and hypertension. Hypotension is low BP (below 100). Hypertension is
high BP (140/90 or higher)
14.
What are the functions of the circulatory system.
a)
Transport oxygen and carbon dioxide, hormones, and nutrients throughout the body
b)
Fight infections
c)
Transport water and wastes
d)
Distribute body heat
e)
Seal wounds (blood clot)
f)
Maintain pH of tissue
g)
Regulate fluid levels (due to lymphatic system)
15.
Explain the difference between the 5 types of blood vessels.(size, structure, thickness, function, BP,
velocity….) arteries – thick, muscular layer causing these vessels to be the thickest; take blood away from the
heart; highest BP; highest blood velocity; low area (thin inside by structure is thick). Arterioles – smaller than
arteries and lead to capillaries; decreases in BP and blood velocity but increases in area due to more paths.
Capillaires – very thin walls and small lumen (only one RBC thick); low BP, low blood velocity, but high area.
Venules – larger lumen than arterioles; low BP; velocity of blood increases from capillary slightly and area
decreases as compared to capillaries. Veins – largest lumen; low BP (need valves to assist with blood
movement), increase in blood velocity from venules (but not as high as arteries) and low area\
16.
How is blood pressure affected by vasodilation? Dilation of vessels lowers BP Vasoconstriction?
Constriction of vessels increases BP What do these 2 terms mean? Vasodilation means the relaxation of muscle
layers in vessels which increases the lumen space inside the vessel whereas vasoconstriction is the contraction
of the muscular layer and therefore, decreases the lumen of vessels.
17.
A) What is Arteriosclerosis? Hardening of the arteries which reduces elasticity of artery wall (associated
with aging)
B) Atherosclerosis? Plaque buildup in arteries due to high saturated fats and cholesterol diet.
C) Aneurysm? Weakening of artery wall which can lead to arteries bursting (most common in arteries leading
to brain)
18.
Name three different places valves are found in the body. Inside the heart (AV valve and semi-lunar valve),
in veins, in lymphatic vessels
19.
Explain the 3 different vascular pathways in the body. Pulmonary circuit; systemic circuit & coronary
circuit (see notes of schematic diagrams)
20.
Explain the process of capillary-tissue fluid exchange.
a)
What is osmotic pressure? The pressure causes by the water content within the blood and affects the
blood volume as well as the exchange that occurs at the capillary level.
b)
How does it affect the capillaries? OP should be at about 21 mm of Hg in order for efficient exchange to
occur between the ECF and the blood capillaries
c)
How is extra fluid taken up from tissues? Via the lymphatic capillaries
21.
Label the following diagram for fluid exchange. Include the pressure in mm Hg on the arteriole and venule
sides of your diagram.
a)
What is the pressure in mm Hg in the other blood vessels?
Arteriole end
Venule end
22.
Name 2 ways blood can bypass the lungs. Via arteriole duct or foramen ovalis
23.
How does the fetal circulatory system change after birth has occurred? Foramen ovalis closes and
becomes an indent with the septum and arteriole duct as well as venous duct are closed off, shrink and become
ligaments
24.
What is plasma? The yellowish, liquid portion of blood that contains gases, water, proteins, wastes,
hormones & salts
25.
What are erythrocytes? RBC Why are they able to carry such a large protein like hemoglobin?
Quaternary protein with iron.
26.
Explain the structure and function of leukocytes. WBCs that fight infection. Larger than RBC, but fewer in
number. Can be granular or agranular
27.
What are platelets? Enucleated, Cell fragments that function in blood clotting Explain the process of
blood clotting. When blood vessel is punctured, platelets congregate and form a plug. Fibrinogen (protein carried
in plasma) is enzymatically converted to fibrin which forms a mesh-like network over wound and this network
traps RBCs..
28.
What is immunity? Body’s ability to eliminate foreign material Explain the functions of the immune
system.defend against pathogens; remove old cells; identifies and destroys abnormal cells; rejects foreign tissue
29.
What is the difference between an antigen and antibody? Antigen (a glycoprotein) is on the surface of
RBCs and the body’s protective response to fight anything foreign is the production of Antibodies. Antibodies
attach to foreign material which “flags” it for destruction by the WBCs
30.
What are the functions of the lymphatic system? Main: take up excess fluid from ECF; others: absorb fat
from intestinal villi; destruction of foreign material; produce antibodies;
31.
What is the structure and function of lymph veins & capillaries? capillaries and veins with valves to prevent
backflow of lymph fluid
32.
What is extracellular fluid (ECF)? The fluid that exists between the blood capillaries, the cells close to
those capillaries and the lymph capillaries
33.
What are lymph nodes? collection of lymph tissue that forms swellings that produce and store
lymphocytes What do they do? Filters debris from lymph fluid
34.
List 4 different lymph organs.Spleen, Thymus gland, Tonsils, Appendix