Deck 24: Circulation

Question 1

In animal cells, diffusion is only effective

A) for oxygen; other substances are actively transported.
B) when animals are active.
C) over distances less than one or two millimetres.
D) across membranes.
E) in animals with lungs.

Answer 1

over distances less than one or two millimetres.

Question 2

Which of the following statements about open circulatory systems is true?

A) Open circulatory systems have a higher peripheral resistance.
B) In open circulatory systems materials are transported from the circulating fluid to the interstitial fluid and then to the cells.
C) Open circulatory systems allow a higher metabolic rate but are energetically expensive.
D) In open circulatory systems, the circulating fluid is anatomically separated from the interstitial fluid.
E) Open circulatory systems return blood more slowly to the heart.

Answer 2

Open circulatory systems return blood more slowly to the heart.

Question 3

In an animal with an open circulatory system

A) the circulating fluid is not pumped.
B) there are no pressure differences within the system.
C) circulating fluid mixes freely with interstitial fluid.
D) circulating fluid does not travel through vessels.
E) All of the answers are correct.

Answer 3

circulating fluid mixes freely with interstitial fluid.

Question 4

Which groups of vertebrates have a completely divided double-circuit circulatory system?

A) All vertebrates
B) All vertebrates except fish
C) Only birds and mammals
D) Fish
E) Amphibians and most reptiles

Question 5

In vertebrate animals, functional separation of deoxygenated and oxygenated blood

A) is called countercurrent circulation.
B) enhances the efficiency of gas exchange.
C) allows stronger contractions of the heart.
D) allows gas exchange by diffusion.
E) is advantageous when air-breathing vertebrates are submerged.

Question 6

In primitive vertebrates the sixth aortic arch carried blood from the ventral aorta through the gills to the dorsal aorta. In reptiles, birds and mammals, the derivative of this vessel carries

A) oxygenated blood from the lungs to the heart.
B) deoxygenated blood from the lungs to the heart.
C) deoxygenated blood from the heart to the lungs.
D) oxygenated blood from the heart to the body.
E) oxygenated blood from the heart to the coronary artery.

Question 7

In the heart of a fish, a one-way valve prevents the back flow of blood from the

A) ventricle into the sinus venosus.
B) atrium into the conus arteriosus.
C) conus arteriosus into the ventricle.
D) sinus venosus into the conus arteriosus.
E) atrium into the sinus venosus.

Question 8

Circulation in amphibians has which of the following features?

A) An unseparated blood stream and a three-chambered heart
B) A partially separated blood stream and a two-chambered heart
C) A completely separated blood stream and a four-chambered heart
D) A partially separated blood stream and a three-chambered heart
E) An unseparated blood stream and a four-chambered heart

Question 9

In the conus arteriosus of the frog, mixing of deoxygenated and oxygenated blood is minimised by

A) a septum.
B) a spiral fold.
C) a spongy wall.
D) the atrium.
E) None of the answers are correct.

Question 10

The pattern of circulation in a submerged crocodile is most like the pattern of circulation in a

A) shark.
B) goanna.
C) human fetus.
D) diving seal.
E) frog.

Question 11

In the mammalian heartbeat

A) contractions are initiated in the wall of the left atrium.
B) ventricles and atria contract at the same time.
C) the left ventricle and the left atrium contract at the same time.
D) the cycle is initiated in the sinus venosus.
E) the two ventricles contract at the same time.

Question 12

In mammalian hearts, the wall of the left ventricle is thicker than that of the right ventricle because

A) systemic pressure is greater than pulmonary pressure.
B) the left ventricle pumps a greater volume of blood than the right ventricle.
C) contractions of the left ventricle fill more arteries than contractions of the right ventricle.
D) blood loses pressure as it passes through the lungs.
E) it arose from a larger aortic arch during evolution.

Question 13

In diastole

A) blood is pumped from ventricles into major arteries.
B) blood flows passively from atria into ventricles.
C) the mitral valve is closed.
D) All of the above are true.
E) the tri-cuspid valve is closed.

Question 14

A recording of the electrical activity of a patient's heart shows that the atria are contracting regularly and normally, but every few beats the ventricles fail to contract. Which of the following is probably not functioning properly?

A) Valves between the atria and the ventricles.
B) Sinoatrial node.
C) Atrioventricular node.
D) Pacemaker.
E) Tricuspid valve.

Question 15

The veins of vertebrates

A) carry blood towards the heart.
B) carry oxygenated blood.
C) contain blood at high pressure.
D) have thick elastic walls.
E) are muscular to create pumping action.

Question 16

Refer to the following diagram showing the relative composition of the walls (endothelium, elastin fibres, smooth muscle, collagen fibres) of four different types of vessels in the vertebrate circulatory system.
Diagram 1 is most likely

A) an artery.
B) an arteriole.
C) a venule.
D) the ventricle.
E) a capillary.

Question 17

Refer to the following diagram showing the relative composition of the walls (endothelium, elastin fibres, smooth muscle, collagen fibres) of four different types of vessels in the vertebrate circulatory system.
Diagram 3 is most likely

A) an artery.
B) an arteriole.
C) a vein.
D) the ventricle.
E) a capillary.

Question 18

Countercurrent heat exchange

A) is an adaptation to shed excess heat from the extremities.
B) transfers heat from a vein to an artery flowing in the same direction.
C) is an adaptation to conserve body heat.
D) is known as vasodilation.
E) occurs only in amphibians and reptiles.

Question 19

In embryonic birds, how many circulatory loops to the placenta are there?

A) None.
B) One.
C) Two.
D) Three.
E) Four.

Question 20

Which blood vessels carry the largest volume of blood?

A) Veins.
B) Capillaries.
C) Major arteries.
D) Arterioles.
E) Left ventricle.

Question 21

At the arteriole end of a capillary the

A) hydrostatic pressure gradient across the capillary wall is greater than the colloid osmotic pressure gradient.
B) colloid osmotic pressure of the interstitial fluid is greater than the colloid osmotic pressure of the blood.
C) hydrostatic pressure of the interstitial fluid is greater than hydrostatic pressure of the blood.
D) hydrostatic pressure gradient across the capillary wall is greater than the colloid osmotic pressure gradient and colloid osmotic pressure of the interstitial fluid is greater than the colloid osmotic pressure of the blood.
E) colloid osmotic pressure of the interstitial fluid is greater than the colloid osmotic pressure of the blood and hydrostatic pressure of the interstitial fluid is greater than hydrostatic pressure of the blood.

Question 22

Within the lymphatic system in vertebrates

A) escaped plasma proteins are returned to the interstitial fluid.
B) lipids are transported away from the digestive system.
C) fluid flows in two directions.
D) blood mixes with interstitial fluid.
E) fluid travels rapidly similar to blood capillaries.

Question 23

Which of the following statements about vertebrate circulation is true?

A) Most blood is contained in the arteries.
B) There is little drop in blood pressure in the capillaries.
C) Diastolic blood pressure is higher than systolic blood pressure.
D) Oxygen level is higher in veins than in arteries.
E) Capillaries contain 90 per cent of the vascular surface area.

Question 24

So that blood flow to individual organs in the mammalian circulatory system can be altered without appreciably affecting blood flow to other organs

A) the arteries supply the major organs in parallel rather than in series.
B) the heartbeat generates relatively high arterial blood pressure.
C) negative feedback systems make compensatory changes to peripheral resistance throughout the circulatory system.
D) baroreceptors detect and respond to changes in blood pressure.
E) All of the answers are correct.

Question 25

Which of the following vessels carries blood at the lowest pressure?

A) The pulmonary artery
B) A capillary in the foot
C) The jugular vein
D) An arteriovenus anastomosis in the skin
E) The carotid artery

Question 26

Tree-climbing snakes spend a considerable amount of time in vertical rather than horizontal orientation. In what way might you expect the circulatory system of tree-climbing snakes to differ from that of ground-dwelling snakes?

A) Reduction in the thickness of the walls of the left ventricle
B) Higher blood pressure in arteries leading to the brain
C) Adaptations to overcome the tendency to develop oedema in their heads
D) Regular cardiac output independent of the body position
E) Larger diameter of arteries leading to the head

Question 27

An increase in sympathetic input and a decrease in parasympathetic (vagal) input to the heart causes

A) the pacemaker to produce action potentials more quickly.
B) an increase in the speed of contraction through the atrioventricular node.
C) an increase to the force of ventricular contraction.
D) an increase in contraction of peripheral arteries.
E) All of the answers are correct.

Question 28

Regulation of arterial blood pressure in vertebrates involves

A) stretch receptors.
B) neural pathways.
C) hormones.
D) chemoreceptors.
E) All of the answers are correct.

Question 29

At the site of damage to a blood vessel, thrombin

A) causes the traumatised vessel to contract.
B) stimulates platelets to release fibrin.
C) causes platelets to break down.
D) binds to platelets to form a clot.
E) converts fibrinogen into insoluble fibrin.

Question 30

Which of the following would you expect to find in both lymph and blood?

A) Erythrocytes
B) Leucocytes
C) Platelets
D) Haemoglobin
E) All of the answers are correct

Question 31

In vertebrates, cardiac output and regional blood flow are regulated by

A) parasympathetic nerves.
B) sympathetic nerves.
C) histamines.
D) adrenaline.
E) All of the answers are correct.

Question 32

Exercise requires homeostatic adjustment in blood flow including

A) increased cardiac output in response to activation of baroreceptors in the vena cava.
B) increased blood pressure in the aortic sinus.
C) increased blood flow to skeletal muscles.
D) increase in the rate of heartbeat.
E) All the answers are correct.

Question 33

If someone with haemoglobin-rich blood, living at high altitude descends to sea level

A) erythropoietin production increases.
B) haemoglobin content of the erythrocytes increases.
C) erythrocyte production decreases.
D) adrenalin synthesis by the sympathetic nerves is increased.
E) All of the answers are correct.

Question 34

The major arteries in vertebrates

A) are thought to have evolved from 6 pairs of aortic arches in primitive vertebrates.
B) are similar in birds and mammals.
C) contain most of the blood in the animal.
D) carry blood from the capillaries to the heart.
E) All of the answers are correct.

Question 35

Coronary arteries

A) in fish, arise as outgrowth from the gills.
B) are thin walled in vertebrates.
C) are separated by a septum which prevents mixing of oxygenated and deoxygenated blood.
D) supply nutrients and oxygen to the heart.
E) are large in amphibians.

Question 36

The Starling Principle states

A) net fluid movement between the capillary and the interstitial fluid is due to the hydrostatic pressure and the colloidal pressure.
B) colloidal osmotic pressure in blood capillaries causes water to move into the capillary.
C) small lipid-soluble molecules diffuse directly through the endothelial cells of capillaries.
D) exchange of lipid-insoluble molecules in capillaries is by pinocytosis.
E) pressurised fluid is forced through gaps between cells of the capillary walls.

Question 37

How many separate atria are present in the hearts of modern amphibians?

A) Two
B) One
C) Three
D) Four
E) None

Question 38

Why would it be advantageous for a reptile basking in the sun to mix oxygenated and deoxygenated blood in its heart?

A) Because it is able to absorb oxygen through the skin
B) Because its heart is a result of incomplete evolution
C) When basking, the reptile has a minimal oxygen requirement
D) Because it has only vestigial lungs
E) Because its pulmonary circulation produces small amounts of oxygen as a by-product of pigmentation reaction with photons from the sun

Question 39

You are presented with a heart from an unknown organism. Upon studying the heart, you note that it has a small node of tissue in the right atrium and that it has a single aorta leading directly from the left ventricle. Based on these observations, from what kind of organism must this heart have come from?

A) Reptile
B) Amphibian
C) Bony fish
D) Bird or mammal
E) Cartilaginous fish

Question 40

When blood enters a mammalian heart, it flows through several valves in a distinct pattern. What is the order in which blood flows through these valves?

A) Aortic semilunar valve, pulmonary semilunar valve, tricuspid valve, mitral valve
B) Pulmonary semilunar valve, mitral valve, tricuspid valve, aortic semilunar valve
C) Tricuspid valve, pulmonary semilunar valve, aortic semilunar valve, mitral valve
D) Tricuspid valve, pulmonary semilunar valve, mitral valve, aortic semilunar valve
E) Mitral valve, aortic semilunar valve, tricuspid valve, pulmonary semilunar valve

Question 41

The human heart consists of how many separate chambers?

A) 4
B) 3
C) 2
D) 1
E) 5

Question 42

A patient presents with a pulmonary semilunar valve that is failing to close properly. This would result in

A) acute chordae tendinae.
B) tricuspid fibrillation.
C) raised diastolic pressure and increased pressure in the pulmonary system.
D) reduction in ventricular angina.
E) Purkinje fibronosis combined with reduced pressure in the pulmonary system.

Question 43

If a living, beating heart of an invertebrate is removed, would it continue to beat? Why/why not?

A) No, as it only contracts in response to stimulation from a nerve
B) No, as it is myogenic
C) Yes, as it only contracts in response to an impulse within the heart itself
D) Yes, as it is neurogenic
E) No, as it is mitrogenic

Question 44

Where is the mammalian heart cycle initiated?

A) In the hypothalamus
B) In the chordae tendinae
C) At the myogenic node in the left atrium
D) At the neurogenic node in the right ventricle
E) At the sinoatrial node in the right atrium

Question 45

In humans, approximately how much of the blood volume lies in the veins, and how do veins raise blood back to the heart?

A) 65% of blood is located in veins, which raise blood to the heart by blood pressure alone.
B) 50% of blood is located in veins, which raise blood to the heart via a diffusible gradient.
C) 75% of blood is located in veins, which raise blood to the heart by compression of muscles located in the vein walls.
D) 40% of blood is located in veins, which raise blood to the heart by gravity.
E) 75% of blood is located in veins, which raise blood to the heart by pressure and external compression resulting from contraction of adjacent muscles.