Question

2. Can you think of a way to remember the relative locations of the three layers2) a. () b. 3. Explain why the tunica media is so thicker in the artery g much than in the vein. C d 4. How do the structures of the blood vessels the largest change arteries divide, becoming smaller arteries, then arterioles capillaries, then ever larger veins. as 5. How is their changing structure related to their changing functions? 6. Compare the structures ofa pancreatic arterial wall (top) with the thin venous wall (just below). This micrograph also shows some of the exocrine tissue of the pancreas a. Note the differences in the tunica media in the two vessels b. What are the primary components of the layer in the artery? c. What do you think would be found in the tunica media of the vein? d. What evidence of elastin is present in the micrograph? (If you would like it larger, drag the comer to increase the size.) O

can you please answer all, i need to study this. please and thank you

Answer 1

2. All arteries and veins contain three layers. The innermost layer is called the tunica intima. The muscular middle layer is called the tunica media, and the outermost layer is called the tunica adventitia. Because capillaries are only one cell layer thick, they only have a tunica intima.

3. Arteries experience a pressure wave as blood is pumped from the heart. This can be felt like a "pulse." Because of this pressure, the walls of arteries are much thicker than those of veins. The vessel walls of veins are thinner than arteries and do not have as much tunica media.

4. There are five types of blood vessels: the arteries, which carry the blood away from the heart; the arterioles; the capillaries, where the exchange of water and chemicals between the blood and the tissues occurs; the venules; and the veins.

• The inner layer, tunica intima, is the thinnest layer. It is a single layer of flat cells (simple squamous epithelium) glued by a polysaccharide intercellular matrix, surrounded by a thin layer of subendothelial connective tissue interlaced with a number of circularly arranged elastic bands called the internal elastic lamina. A thin membrane of elastic fibers in the tunica intima run parallel to the vessel.
• The middle layer tunica media is the thickest layer in arteries. It consists of circularly arranged elastic fiber, connective tissue, polysaccharide substances, the second and third layer are separated by another thick elastic band called external elastic lamina. The tunica media may (especially in arteries) be rich in vascular smooth muscle, which controls the caliber of the vessel. Veins don't have the external elastic lamina, but only an internal one. The tunica media is thicker in the arteries rather than the veins.
• The outer layer is the tunica adventitia and the thickest layer in veins. It is entirely made of connective tissue. It also contains nerves that supply the vessel as well as nutrient capillaries (vasa vasorum) in the larger blood vessels.

Capillaries consist of a single layer of endothelial cells with a supporting subendothelium consisting of a basement membrane and connective tissue.

When blood vessels connect to form a region of diffuse vascular supply it is called an anastomosis. Anastomoses provide critical alternative routes for blood to flow in case of blockages.

Leg veins have valves which prevent backflow of the blood being pumped against gravity by the surrounding muscles.

5.

There are various kinds of blood vessels:

• Arteries
• Elastic arteries
• Distributing arteries
• Arterioles
• Capillaries (the smallest blood vessels)
• Venules
• Veins
  • Large collecting vessels, such as the subclavian vein, the jugular vein, the renal vein and the iliac vein.
  • Venae cavae (the two largest veins, carry blood into the heart).
• Sinusoids
  • Extremely small vessels located within bone marrow, the spleen, and the liver.

They are roughly grouped as "arterial" and "venous", determined by whether the blood in it is flowing away from (arterial) or toward (venous) the heart. The term "arterial blood" is nevertheless used to indicate blood high in oxygen, although the pulmonary artery carries "venous blood" and blood flowing in the pulmonary vein is rich in oxygen. This is because they are carrying the blood to and from the lungs, respectively, to be oxygenated.

In all arteries apart from the pulmonary artery, hemoglobin is highly saturated (95–100%) with oxygen. In all veins apart from the pulmonary vein, the saturation of hemoglobin is about 75%. (The values are reversed in the pulmonary circulation.) In addition to carrying oxygen, blood also carries hormones, waste products and nutrients for cells of the body.

Blood vessels do not actively engage in the transport of blood (they have no appreciable peristalsis). Blood is propelled through arteries and arterioles through pressure generated by the heartbeat. Blood vessels also transport red blood cells which contain the oxygen necessary for daily activities. The amount of red blood cells present in your vessels has an effect on your health. Hematocrit tests can be performed to calculate the proportion of red blood cells in your blood. Higher proportions result in conditions such as dehydration or heart disease while lower proportions could lead to anemia and long-term blood loss.

Blood vessels also transport red blood cells which contain the oxygen necessary for daily activities. The amount of red blood cells present in your vessels has an effect on your health. Hematocrit tests can be performed to calculate the proportion of red blood cells in your blood. Higher proportions result in conditions such as dehydration or heart disease while lower proportions could lead to anemia and long-term blood loss.

Permeability of the endothelium is pivotal in the release of nutrients to the tissue. It is also increased in inflammation in response to histamine, prostaglandins and interleukins, which leads to most of the symptoms of inflammation (swelling, redness, warmth and pain).

6. i)

The middle layer tunica media is the thickest layer in arteries. It consists of circularly arranged elastic fiber, connective tissue, polysaccharide substances, the second and third layer are separated by another thick elastic band called external elastic lamina. The tunica media may (especially in arteries) be rich in vascular smooth muscle, which controls the caliber of the vessel. Veins don't have the external elastic lamina, but only an internal one. The tunica media is thicker in the arteries rather than the veins.

ii)

The arteries and veins have three layers. The middle layer is thicker in the arteries than it is in the veins:

• The inner layer, tunica intima, is the thinnest layer. It is a single layer of flat cells (simple squamous epithelium) glued by a polysaccharide intercellular matrix, surrounded by a thin layer of subendothelial connective tissue interlaced with a number of circularly arranged elastic bands called the internal elastic lamina. A thin membrane of elastic fibers in the tunica intima run parallel to the vessel.
• The middle layer tunica media is the thickest layer in arteries. It consists of circularly arranged elastic fiber, connective tissue, polysaccharide substances, the second and third layer are separated by another thick elastic band called external elastic lamina. The tunica media may (especially in arteries) be rich in vascular smooth muscle, which controls the caliber of the vessel. Veins don't have the external elastic lamina, but only an internal one. The tunica media is thicker in the arteries rather than the veins.
• The outer layer is the tunica adventitia and the thickest layer in veins. It is entirely made of connective tissue. It also contains nerves that supply the vessel as well as nutrient capillaries (vasa vasorum) in the larger blood vessels.

iv) The tunica media is thicker in the arteries rather than the veins.