Anatomy: Cardiovascular

Question 1

What are the two circulatory systems?

Answer 1

Systemic

Pulmonary

Question 2

What three distinct layers make up the arteries and veins? How can arteries and veins be distinguished?

Answer 2

1. Tunica intima - innermost layer made up of a single layer of endothelial cells
2. Tunica media - middle layer composed of primarily smooth muscle
3. Tunica externa / adventitia - outermost connective tissue layer

Arteries and veins are distinguished by the thickness of tunica media.

Question 3

What is an arteriole?

Answer 3

Smaller diameter arteries connecting arteries to capillaries.

Question 4

What is a capillary bed?

Answer 4

Comprises on capillaries, The capillary bed is a network that connects arterioles and venules.

Question 5

What is a venule?

Answer 5

Smaller diameter veins, connecting capillaries to veins.

Question 6

What is a valve cusp?

Answer 6

Valves in veins are bicuspid, meaning they have two flap-like structures that regulate blood flow. The valves’ main job is to keep the blood moving in one direction – back up towards the heart.

Question 7

Which blood vessels have thicker walls and why?

Answer 7

Arteries

To withstand higher pressure of blood from the heart

Question 8

How many layers do capillaries have?

Answer 8

One cell thick and composed of tunica intima to allow for exchange of molecules between blood and cells

Question 9

What effect does the sympathetic nervous system have on arteries?

Answer 9

The sympathetic nervous system will constrict arteries

Question 10

Which layer of the blood vessels is innervated by the sympathetic nerves?

Answer 10

Tunica media

Question 11

What are capillaries and capillary beds, and what is their function?

Answer 11

Capillaries are the smallest blood vessels in the body and connect arterioles and venules. This network is known at capillary beds. The capillaries are responsible for facilitating the transport and exchange of gasses, fluids, and nutrients in the body. The capillaries also function to receive carbon dioxide and waste products that are then delivered to the kidneys and liver (for wastes) and the lungs (for exhalation of carbon dioxide).

Question 12

What are the precapillary sphincters?

Answer 12

At the point where each of the capillaries originates from an arteriole, a smooth muscle fiber encircles the capillary. This is called the precapillary sphincter.

The sphincter will expand and contract as required for physiological functioning. If all of the sphincters are closed, then the blood will flow directly from the arteriole to the venule through the thoroughfare channel.

Question 13

When doing bicep curls, what is most likely going to happen within the capillary bed?

Answer 13

The precapillary sphincters will relax and blood will flow into the capillaries within the capillary bed within the biceps muscle

Question 14

What happens during atrial filling?

Answer 14

Deoxygenated blood (blue) from the body is pumped back to the heart via the superior vena cava (head, neck and arms) and inferior vena cava (lower parts of body) and into the right atrium.

Oxygenated blood (red) from the lungs in returned to the heart via the pulmonary veins and into the left atrium. There are four pulmonary veins (two from each lung).

Question 15

How does blood go from atria to ventricles?

Answer 15

Once the atria have filled, they contract. This will increase pressure and push open the atrioventricular valves. The atrioventricular valves are the valves that separate the atria from the ventricles.

These valves are named according to the number of cusps each has. The tricuspid valve has three cusps and lies between the right atrium and right ventricle. The mitral valve (or bicuspid valve) has two cusps and lies between the left atrium and left ventricle.

Once the atria contract and the atrioventricular valves open, blood flows from the atria (right and left) to the ventricles (right and left).

Question 16

What happens during ventricular filling?

Answer 16

Once the ventricles (left and right) have filled, they will contract. This will increase the pressure within the ventricles and will close the atrioventricular valves to prevent back flow into the atria.

Question 17

How does blood flow from ventricles to lungs/body?

Answer 17

Once the walls of the ventricles (left and right) contract and ventricular pressure increases, blood will flow through the semilunar valves and either into the pulmonary trunk (blue) from the right ventricle or the aorta (red) from the left ventricle.

The semilunar valves are the valves at the bases of the aorta and the pulmonary trunk, consisting of three cusps which prevent the flow of blood back into the heart.

The pulmonary trunk divides into a left and right pulmonary arteries that will transport deoxygenated blood from the right ventricle to the lungs. Once blood is oxygenated, it will return to the heart via the pulmonary veins (see atrial filling). This process forms part of the pulmonary circulation.

The aorta will transport oxygenated blood to the body. Deoxygenated blood will then return to the heart via the venous system (see atrial filling). This forms part of the systemic circulation.

Question 18

Where are the coronary arteries and what do they supply?

Answer 18

The coronary arteries branch off at the base of the ascending aorta. These arteries will supply blood to the heart.

Question 19

Where is the ascending aorta?

Answer 19

This part of the aorta rises from the left ventricle.

Question 20

What is the brachiocephalic trunk?

Answer 20

The brachiocephalic trunk supplies blood to the right arm and head and neck. It gives rise to two arteries.

Question 21

What is the right subclavian artery?

Answer 21

The right subclavian artery supplies blood mainly to the right arm. It is a branch of the brachiocephalic trunk.

Question 22

What is the right common carotid artery?

Answer 22

The right common carotid artery supplies blood to the right side of the head and neck. It is a branch of the brachiocephalic trunk.

Question 23

What is the left common carotid artery?

Answer 23

The left common carotid artery supplied blood to the left side of the head and neck. It originates from the aortic arch.

Question 24

What is the left subclavian artery?

Answer 24

The left subclavian artery supplies blood mainly to the left arm. It originates from the aortic arch.

Question 25

What is the aortic arch and what are its three branches?

Answer 25

This is the part of the aorta that arches between the ascending aorta and descending aorta. The aortic arch gives rise to three main arteries (brachiocephalic trunk, left common carotid and left subclavian) that will supply blood to the arms, head and neck.

Question 26

What is the name of the structure that the heart sits in?

Answer 26

Pericardium

It has two layers - fibrous and serous

Question 27

Which chamber forms the apex of the heart?

Answer 27

Left ventricle

Question 28

Which chamber is most visible on the anterior aspect of the heart?

Answer 28

Right ventricle

Question 29

Which structures are part of the systemic circulation?

Answer 29

Left ventricle
Right atrium
Superior/inferior vena cava
Aorta

Question 30

Which structures are part of the pulmonary circulation?

Answer 30

Right ventricle
Pulmonary veins
Left atrium
Pulmonary arteries

Question 31

Although the skier has a jacket on, he is still cold. How can his circulatory system help keep him warm?

Answer 31

The arterioles at the surface of his skin can vasoconstrict so less heat leaves his body.

Question 32

How do valves work in the body, and specifically in the leg?

Answer 32

In general, valves ensure blood moves in the right direction.
In the leg, venous valves ensure blood moves upward and back towards the heart.

Question 33

What is the main artery in the abdomen and how does it split off?

Answer 33

The abdominal aorta is a continuation of the descending aorta in the thorax. Along with supply blood to the abdominal organs, its terminal branches continues into the pelvis to supply organs of the pelvis as well as the lower limb. The abdominal organs receive blood from three unpaired arteries of the abdominal aorta.

Question 34

What is the coeliac trunk and what does it supply?

Answer 34

The coeliac trunk is a major unpaired artery that supplies the foregut of the gastrointestinal tract. It arises from the abdominal aorta at the level of the twelfth thoracic vertebrae. It gives off three major branches called left gastric, common hepatic and splenic arteries

Question 35

What is the superior mesenteric artery and what does it supply?

Answer 35

The superior mesenteric artery (SMA) is a major unpaired artery of the abdomen. It arises from the abdominal aorta at approximately lumbar vertebral level L1, and supplies arterial blood to the organs of the midgut – which spans from the duodenum to the proximal 2/3 of the transverse colon.

Question 36

What is the inferior mesenteric artery and what does it supply?

Answer 36

The inferior mesenteric artery (IMA) is a major unpaired branch of the abdominal aorta arising at approximately lumbar vertebral level L3. It supplies arterial blood to the organs of the hindgut – which spans the distal 1/3 of the transverse colon, splenic flexure, descending colon, sigmoid colon and rectum.

Question 37

Which organs are supplied by the coeliac trunk?

Answer 37

Spleen
Liver
Pancreas
Stomach
Duodenum

Question 38

Which organs are supplied by the superior mesenteric artery?

Answer 38

Transverse colon (2/3)
Caecum
Jejunum
Ileum
Ascending colon
Appendix
Pancreas

Question 39

Which organs are supplied by the inferior mesenteric artery?

Answer 39

Sigmoid colon
Descending colon
Rectum
Transverse colon (1/3)

Question 40

What type of veins are present in the limbs?

Answer 40

There are superficial and deep veins within the limbs. The deep veins are named after the artery that they accompany. For example the popliteal artery is accompanied by the popliteal vein and the ulnar artery is accompanied by the ulnar vein.

The superficial veins drain into the deep veins and lie within the subcutaneous tissue.