circulatory system

Question 1

what are the differences between arteries and veins?

Answer 1

arteries have a thick, smooth muscular wall transporting blood under high pressure.

veins have thinner walls and transport blood under lower pressure, but contain more blood by volume

Question 2

what are the three layers of a blood vessel?

Answer 2

tunica intima - connective tissue, endothelium and basement membrane

tunica media - elastic tissue and muscle

tunica adventitia

Question 3

when is the maximum arterial pressure measured?

Answer 3

when the ventricle contracts and blood is pumped into the arterial system

Question 4

when is minimum arterial pressure measured?

Answer 4

when the ventricle is relaxed and blood is returned to the heart via veins

Question 5

what is meant by pulse pressure?

Answer 5

the difference between systolic and diastolic pressure

Question 6

where is peripheral resistance the highest?

Answer 6

arterioles

Question 7

what is the composition of the blood?

Answer 7

55% plasma

45% formed elements

Question 8

what proteins are present in plasma?

Answer 8

albumin
globulins
fibrinogen

Question 9

what are the formed elements of the blood?

Answer 9

RBCs (erythrocytes)
platelets (thrombocytes)
white blood cells (leukocytes)

Question 10

what is the function of albumin?

Answer 10

maintains osmotic pressure and helps transport substances in the blood

Question 11

what is the relevance of Ca2+ ions in the blood?

Answer 11

important for clotting, signal platelets to aggregate

Question 12

what are granulocytes?

Answer 12

a group of white blood cells including neutrophils, eosinophils and basophils

Question 13

what are neutrophils?

Answer 13

granulocytes involved in first response to infection. phagocytic

Question 14

what do basophils do?

Answer 14

release heparin and histamine

Question 15

what does haematocrit measure?

Answer 15

volume in the blood occupied by RBCs as a percentage. normal value = approx 45%

Question 16

what happens when the dissociation curve for Hb shifts left?

Answer 16

at a given PO2 in the tissue, there is decreased release of O2 and affinity for O2 is increased

Question 17

what happens when the dissociation curve for Hb shifts to the right?

Answer 17

increased unloading of O2, affinity for O2 decreased

Question 18

what causes a rightward shift of the Hb dissociation curve?

Answer 18

muscle is hot (such as in exercise)
low pH
hypercapnia
high levels of organic phosphates

Question 19

what is the startling equation?

Answer 19

an equation that describes the role of hydrostatic and oncotic forces in the movement of fluid across the capillary membranes as a result of filtration

Question 20

when is filtration favoured?

Answer 20

when the blood pressure is greater than the osmotic pressure, fluid moves out of the capillary

Question 21

when is reabsorption favoured?

Answer 21

when blood pressure is less than osmotic pressure, fluid enters capillary

Question 22

how do interstitial fluids enter the lymphatic system?

Answer 22

via lymphatic capillaries assisted by osmotic pressure