Blood Vessels

Question 1

How many layers are in the basic structure of a blood vessel

Answer 1

3
Tunica intima
Tunica media
Tunica adventitia

Question 2

What are the layers of a blood vessel from inner to outermost

Answer 2

Tunica intima
Tunica media
Tunica adventitia

Question 3

What is the tunica intima made up of

Answer 3

A single layer of squamous epithelial cells termed endothelial cells supported by a basal lamina and a thin layer of connective tissue

Question 4

What is the tunica media made up of

Answer 4

Made up of predominantly smooth muscle. Thickness can vary tremendously

Question 5

What is the tunica adventitia made up of

Answer 5

Made up of supporting connective tissue

Question 6

What separates the tunica intima from the tunica media

Answer 6

A layer of elastic tissue called the internal elastic membrane

Question 7

What separates the tunica media and the tunica adventitia

Answer 7

A layer of elastic tissue called the external elastic membrane

Question 8

What are vasa vasorum

Answer 8

Small blood vessels that supply the walls of larger arteries.

Question 9

What are capillaries composed of

Answer 9

Capillaries are composed of endothelial cells and a basal lamina

Question 10

How many types of capillaries are there

Answer 10

3
Continuous
Fenestrated
Discontinuous or sinusoidal

Question 11

Examples of continuous capillaries

Answer 11

Muscle, nerve, lung, skin

Question 12

Examples of fenestrated capillaries

Answer 12

Gut mucosa, endocrine glands, kidney

Question 13

Examples of discontinuous or sinusoidal capillaries

Answer 13

Liver, spleen, bone marrow

Question 14

Why do small veins have valves

Answer 14

To prevent back flow of blood

Question 15

How is lymph moved to lymph nodes

Answer 15

No central pump, but smooth muscle in walls, hydrostatic pressure in the tissue and compression of the vessels by voluntary muscle, combined with valves in the vessels, produces flow.

Question 16

Where is blood found in the body

Answer 16

Peripheral veins, heart and lungs, peripheral arteries and capillaries.

Question 17

How is serum obtained when separating blood

Answer 17

Serum is usually obtained by allowing the blood to clot, and then removing the clot before spinning the blood.

Question 18

Describe Erythrocytes

Answer 18

Often termed Red Blood Cells.
Biconcave discs.
They are not true cells as they have no nucleus or organelles.
1/3 of their volume taken up by the iron containing protein haemoglobin.
They contain a network of flexible cytoskeletal elements that allow them to deform and slip through smaller spaces than themselves.

Question 19

What are Leukocytes, and how many types are there.

Answer 19

White blood cells
5 - (neutrophils, eosinophils, basophils, lymphocytes, monocytes)

Question 20

What is the most common type of leukocyte

Answer 20

Neutrophils are granulocytes and are the most common type of leukocyte.

Question 21

What happens when Neutrophils are stimulated.

Answer 21

Neutrophils circulate in an inactive state, but if stimulated, for example by the presence of bacteria or inflammation, they enter the tissue where they are highly motile phagocytes.

Question 22

Why is a significant portion of bone marrow devoted to the production of Neutrophils.

Answer 22

Neutrophils are both abundant and short lived which means a significant potion of the bone marrow is devoted to their production.

Question 23

Describe Eosinophils

Answer 23

Eosinophils typically have a bilobed nucleus.

Question 24

Why are granules important in Eosinophils.

Answer 24

Their granules contain a variety of hydrolytic enzymes and they are important in inducing and maintaining inflammation, particularly in allergic reactions and asthma. They are also important in fighting parasitic infection.

Question 25

Describe basophils

Answer 25

Basophils are the rarest of the granulocytes.

Question 26

What gives basophils an intense stain colour.

Answer 26

The prominent granules in the cytoplasm of basophils have an affinity for basic dyes such as methylene blue and with this dye, stain intensely blue-purple.

Question 27

Describe Basophils

Answer 27

Basophils have a bilobed nucleus but this is often obscured by the granules. these granules contain histamine, heparin and other inflammatory mediators.

Question 28

Describe how basophils respond in allergic reactions.

Answer 28

Basophils act as effector cells in allergic reactions. High affinity IgE receptors in their cell membrane are directed against a particular allergen and when they bind their antigen the cell is stimulated to release its granules. this leads to hay fever, allergic asthma, allergic dermatitis.

Question 29

What are Monocytes?

Answer 29

Monocytes serve as the precursors of tissue macrophages and together they form what is termed the mononuclear phagocyte system.

Question 30

Where are macrophages found?

Answer 30

Macrophages are widely distributed in the body, but are particularly found in loose connective tissue.

Question 31

Do Monocytes have lysosomal granules in their cytoplasm.

Answer 31

monocytes have numerous small lysosomal granules in their cytoplasm. They are the largest cells circulating in the blood and have a non-lobulated nucleus which often appears kidney bean-shaped.

Question 32

Describe Lymphocytes

Answer 32

Lymphocytes have a round nucleus surrounded by a thin to moderate rim of cytoplasm that does not have visible granules.

Question 33

How many classes of lymphocytes are there

Answer 33

There are 2 general classes of lymphocytes, B cells and T cells, however these cannot be distinguished in routine stained sections.

Question 34

What are the differences and similarities between B cells and T cells.

Answer 34

Both types of lymphocytes arise in the bone marrow, but T cells differentiate in the thymus. both cell types participate in the specific immune response. B cells given rise to antibody secreting plasma cells while T cells form a complex set of cells that perform many defence functions.

Question 35

What are platelets

Answer 35

In addition to red blood cells and leukocytes, the formed elements of blood include platelets. these are small cell fragments found in large numbers in the blood. Platelets play a key role in hemostasis (prevention of blood loss).

Question 36

Explain platelets and their skeletons.

Answer 36

Platelets have a well developed cytoskeleton, which participates in extrusion of granules and in clot retraction. platelets have some organelles, but no nucleus. they have conspicuous granules that include, among other things, some coagulation factors.

Question 37

What is hemopoiesis

Answer 37

Earliest site for erythrocyte formation is outside the embryo in the yolk sac beginning at about 3 weeks gestation. Later the liver and to some extent the spleen is colonised by hemopoietic stem cells. thus during the second trimester the liver is the principal site of blood formation.

Question 38

What is the main site of blood formation by birth

Answer 38

By birth the bone marrow is the main site of blood formation and essentially all bones participate. as bones enlarge there is excess capacity and so hemopoiesis is shut down in many bones.

Question 39

By the time the skeleton reaches maturity which bones retain hemopoiesis.

Answer 39

By the time the skeleton reaches maturity, only the vertebrae, ribs, skull, pelvis and proximal femurs retain hemopoiesis.

Question 40

What are Megakaryocytes

Answer 40

Megakaryocytes are large cells of bone marrow that produces platelets. It undergoes multiple duplications of its nuclear material but doesn't undergo nuclear or cell division-so the nucleus is very large. the platelets are formed as extensions at the outer margin of the cell which fragment from the cell.