Question 1

What differentiates a closed circulatory system from an open circulatory system?

Accepted Answer

D

Question 2

Arthropod hearts share some common features.Which of the following is NOT a feature of all arthropod hearts?

Accepted Answer

Arthropod hearts typically have neurogenic action potentials, where nerve impulses trigger heart contractions, rather than myogenic action potentials, which originate from within the muscle itself.

Question 3

Tetrapods have two circuits within their circulatory system.The one that pushes blood through the lungs is called the

Accepted Answer

The circuit that pushes blood through the lungs is the pulmonary circuit, as it carries blood to the lungs for oxygenation before returning it to the heart. The systemic circuit carries oxygenated blood to the rest of the body. The capillary circuit refers to the smallest blood vessels where gas exchange occurs, and the aortic circuit is not a recognized term in circulation physiology.

Question 4

What type of capillary is normally found in the kidney?

Accepted Answer

Fenestrated capillaries are commonly found in the glomeruli of the kidney, where they allow for the filtration of blood in the formation of urine.

Question 5

In mammals,heart size tends to be proportional to body weight while heart rate is inversely proportional to body weight.What is the most probable explanation for pygmy shrews having unusually large hearts but an unusually slow heart rate?

Accepted Answer

The fact that pygmy shrews have unusually large hearts but an unusually slow heart rate suggests that their heart rate has reached its limit, and therefore a larger heart is able to pump more blood with each beat. This is likely due to the small size of the shrew, which may make it difficult to maintain a faster heart rate without sacrificing efficiency.

Question 6

How many hearts does an octopus have?

Accepted Answer

An octopus has three hearts, which help it to pump blood through its entire body. Two of these hearts work to pump blood to the gills, while the third heart pumps blood through the rest of the body.

Question 7

What is believed to be the major evolutionary pressure in the development of closed circulatory systems?

Accepted Answer

The development of a closed circulatory system enables efficient transport of oxygen to all parts of the organism, which is a major advantage in aerobic respiration. This increased efficiency likely provided a selective advantage in the evolution of closed circulatory systems.

Question 8

How do veins prevent the backflow of blood?

Accepted Answer

Veins prevent the backflow of blood with the help of valves. These one-way valves ensure that blood flows towards the heart and prevents any reverse flow. Gravity and pressure may aid in the flow of blood but are not responsible for preventing backflow. Bulk flow refers to the overall movement of fluids in the body and is not directly related to the prevention of backflow.

Question 9

In most non-crocodilian reptiles,the ventricle is divided into three chambers.Which of the following is NOT one of the chambers?

Accepted Answer

The cavum cardiacum is not one of the chambers of the ventricle in most non-crocodilian reptiles. The ventricle is typically divided into the cavum venosum, cavum pulmonale, and cavum arteriosum.

Question 10

The general term for blood vessels that carry blood away from the heart is

Accepted Answer

Arteries are blood vessels that carry oxygenated blood away from the heart to the rest of the body. The aorta is a specific large artery that carries blood directly from the heart, but not all arteries are as large or direct. Veins carry blood back to the heart, and atria are the two upper chambers of the heart that receive blood.

Question 11

What is NOT one of the functional distinctions between arteries and veins?

Accepted Answer

While it is true that veins often carry deoxygenated blood, it is not a functional distinction between arteries and veins. Both capillaries and veins can carry deoxygenated blood, depending on their location and function.

Answer: B
 While there are some exceptions, veins usually have a thinner vessel wall than arteries. This allows them to easily expand and contract as blood flows through them.

Answer: C
 While veins do have some elasticity, they are not easily stretched. This is because they do not have the same thick layers of smooth muscle and elastic tissue as arteries.

Answer: D
 One-way valves are a key functional distinction between veins and arteries. These valves help to prevent blood from flowing backwards and ensure that blood is transported efficiently back to the heart.

Question 12

Vasoconstriction is the result of the contraction of smooth muscle of the

Accepted Answer

Vasoconstriction is the narrowing of a blood vessel, which is the result of the contraction of smooth muscle cells found in the tunica media layer of the blood vessel wall. The tunica intima is the innermost layer, the tunica externa is the outermost layer, and the tunica lumena is the hollow space within the blood vessel.

Question 13

Which of the following fluids is NOT circulated by the cardiovascular system?

Accepted Answer

Lymph is not circulated by the cardiovascular system. It is part of the lymphatic system and is circulated separately from the blood.

Question 14

How does the dorsal blood vessel of the earthworm pump blood?

Accepted Answer

The dorsal blood vessel in an earthworm pumps blood through peristalsis, which is a series of wave-like muscle contractions that move food through the digestive tract in many animals, but in the context of the earthworm's circulatory system, it helps to propel blood.

Question 15

Which of the following is NOT one of the essential components of a circulatory system?

Accepted Answer

While oxygen is necessary for the proper functioning of the circulatory system, it is not an essential component of the system itself. The three essential components of a circulatory system are a pump (such as the heart), a system of tubes (such as blood vessels), and a fluid (such as blood).

Question 16

The vertebrate heart muscle is known as

Accepted Answer

The myocardium is the thick, muscular layer of the heart wall that is responsible for the contraction of the heart and pumping of blood. The pericardium is the sac-like membrane that surrounds the heart, while the epicardium is the outermost layer of the heart wall. The endocardium is the innermost layer of the heart wall that lines the chambers and valves.

Question 17

Fish hearts consist of __________ chambers arranged in a series.

Accepted Answer

The answer of Fish hearts consist of __________ chambers arranged...

Question 18

In the bony fish,all heart chambers are contractile except the

Accepted Answer

The bulbus arteriosus in bony fish is not a contractile chamber; it acts as a buffering and smoothing structure to regulate the flow of blood into the systemic circulation, unlike the sinus venosus, atrium, and ventricle, which are contractile.

Question 19

In fishes and amphibians,spongy myocardium receives oxygen from

Accepted Answer

In fishes and amphibians, the spongy myocardium is oxygenated directly by the blood present in the heart chambers, unlike mammals where the heart muscle is primarily oxygenated by the coronary arteries.

Question 20

Excluding capillaries in the central nervous system,the least permeable type of capillary is the

Accepted Answer

Continuous capillaries are the least permeable type of capillary due to their tight junctions between adjacent endothelial cells. This tight junction limits the passage of large molecules and cells. Fenestrated capillaries have small pores in their endothelial cells, allowing for more permeability, while sinusoidal capillaries have large gaps between their endothelial cells, allowing for even greater permeability. Occluding capillaries do not exist.

Quiz 9: Circulatory Systems