March 5, 2015 --> 45-60 Flashcards Preview

BOARD: Biochemistry (Dental Decks) > March 5, 2015 --> 45-60 > Flashcards

Flashcards in March 5, 2015 --> 45-60 Deck (29):
1

Which part of the heart is the pump for the pulmonary circuit?

Right ventricle

2

Which part of the heart is the pump for the systemic circuit?

Left ventricle

3

The vessels of the pulmonary circuit supply blood to what?

Only to the alveoli! nothing else

4

T or F, Volume of blood flow per min is the same in both pulmonary and systemic circuits

True

5

Mean arterial blood pressure is configured how?

Cardiac output x Total peripheral resistance

6

Vascular compliance is mathematically figured how?

Increase in volume/Increase in pressure

7

Why is the blood pressure in pulmonary circuit lower than that of the systemic circulation

Because pulmonary arterioles are usually dilated and have little resistance to blood flow. The pulmonary vessels are highly compliant, allowing the pulmonary circuit to store blood volume without changing blood pressure

8

2 important points about compliance

1. Compliance decreases at higher pressures and volumes
2. At lower pressures, the compliance of a vein is about 10-20 times greater than that of an artery

9

What makes veins suitable for use as arterial by-pass grafts?

Because at higher pressures and volumes, venous compliance becomes similar to arterial compliance.

10

Give values for the mean blood pressure in the aorta, end of the arterioles and in the vena cava

Aorta = 100 mmHg
End of the arterioles = 30 mmHg
Vena Cava = 4 mmHg

11

The baroreceptor regulatory system is composed of two groups of stretch receptors:

1. Group of receptors in the Carotid sinuses
2. Group of receptors in the arch of the aorta

- These detect changes in blood pressure and feed into back to cardiac control center and vasomotor center in medulla

12

If the blood pressure is too high, what nervous impulse will act to reduce the pressure?

The dominance of parasympathetic impulses will reduce the pressure by slowing the heart rate, reducing stroke volume and dilating blood "reservoir" vessels

13

The sympathetic impulses that are activated by baroreceptors are in response to what situation?

If the pressure is too low. If this occurs, the dominance of sympathetic impulses will increase the pressure by increasing the heart rate, stroke volume and constricting reservoir vessels

14

What part of the artery is innervated by autonomic fibers?

Tunica media (smooth muscle)

15

Give the layers of the artery

Tunica Adventitia (fibrous connective tissue)
Tunica Media (smooth muscle; elastic connective tissue)
Tunica Intima (endothelium)

16

T or F, All blood vessels (arteries, veins & capillaries) have 3 layers namely the tunica adventitia, tunica media and the tunica intima

False, Capillaries only have the tunica intima

17

Which vessel has the largest pressure?

Arteries

18

Which vessel has the largest resistance?

Arterioles

19

Which vessel has the largest cross-sectional area

Capillaries

20

Which vessel has the largest blood volume

Veins

21

How does the HIV/AIDS virus produce DNA from an mRNA molecule?

Using the enzyme "reverse transcriptase"

22

Reverse transcriptase enzymes are found naturally in certain viruses called what?

Retroviruses

23

Describe retroviruses

They are viruses in which the genetic information is carried on an RNA molecule. When one of these viruses infects a host cell, it uses this enzyme to make a complementary DNA copy of its genetic information which is then incorporated into the host DNA

24

What drug is a competitive inhibitor of the HIV reverse transcriptase?

The drug AZT (a thymidine analog)

25

The HIV virus is why type of virus

Retrovirus

26

T or F, Ribosomes are surrounded by a membrane

False, they ARE NOT surrounded by a membrane

27

Which direction does the DNA polymerase read DNA as it is replicating and in which direction is the new, complementary continuous strand of DNA made?

Read: 3' --> 5'
New DNA made: 5' --> 3'

28

Which Enzyme joins okazaki fragments together to form a continuous strand of DNA

DNA ligase

29

Which enzymes are responsible for unwinding supercoiled DNA to allow DNA polymerase access to replicate the genetic code?

Topoisomerases