Histology and Blood Vessels Flashcards Preview

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Flashcards in Histology and Blood Vessels Deck (52)
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1
Q

What components make up blood?

A

Plasma (55%)
Red cells (erythrocytes)
White cells (leukocytes)
Platelets

2
Q

What is in the blood plasma?

A

Water (90%)
Proteins
Nutrients
Salts

3
Q

What are erythrocytes?

A

Red blood cells

4
Q

What are leukocytes?

Name 5

A

White blood cells

  • neutrophils
  • eosinophils
  • basophils
  • lymphocytes
  • monocytes
5
Q

What are platelets?

A

Cell fragments, 2 micrometers, involved in hemostasis
Well developed cytoskeleton which aids extrusion of granules and the clotting
Some organelles, no nucleus
Contain coagulation factors within some granules

6
Q

What is the internal elastic membrane?

A

Layer of elastic tissue separating tunica intima and tunica media

7
Q

What is the external elastic membrane?

A

Layer of elastic tissue separating tunica media from tunica adventitia

8
Q

Do elastic fibres show up with common stains?

A

No, specialised stains must be used

9
Q

What are elastic arteries?

A

Large arteries which contain less smooth muscle and more elastic fibres within tunica media to enable them to stretch and shrink during the cardiac cycle and maintain consistent blood pressure

10
Q

What is the vaso vasorum?

A

Blood supply to tissues within large blood vessel wall (excluding tunica intima)

11
Q

Why do tissues in the large blood vessel walls need a separate blood supply?

A

Only tunica intima can access nutrients and oxygen from blood in lumen

12
Q

How is the vessel wall of a small arteriole different to that of an artery?

A

Less smooth muscle

Very small tunica adventitia

13
Q

What are vaso nervorum?

A

Nerves supply blood vessels

14
Q

Describe the structure of a capillary

A

No smooth muscle
Simple squamous epithelial cells connected to basal lamina
Diameter of 4 - 8 micrometers (RBC is 7 micrometers)

15
Q

Name the three types of capillary

A

Continuous
Fenestrated - contain small pores
Discontinuous / sinusoidal - contain large gaps between cells

16
Q

At what point does capillary turn into a venule?

A

When patches of smooth muscle start to appear in the tunica media

17
Q

Where do capillaries drain to?

A

Post - capillary venules consisting of endothelial cells and thin layer of connective tissue

Important site for exchange eg cells from blood can move into tissues during inflamation response

18
Q

Describe structure of veins

A

Contain valves to prevent backflow of blood
Thin tunica media with a layers of few smooth muscle cells
Substantial tunica adventitia

Largest veins have very large tunica adventitia with bundles of longitudinal smooth muscle

19
Q

Do lymph vessels contain valves?

A

Yes

20
Q

Where do lymphatic vessels take lymph?

A

To nodes for immune surveillance

Back to blood stream at veins at root of neck

21
Q

How is lymph moved through the lymphatic system?

A

Via

  • smooth muscle in vessel walls
  • hydrostatic pressure in tissue
  • compression of vessels by voluntary muscles
  • valves
22
Q

How is lymph moved through the lymphatic system?

A

Via

  • smooth muscle in vessel walls
  • hydrostatic pressure in tissue
  • compression of vessels by voluntary muscles
  • valves
23
Q

How much blood does the average adult have?

A

4.5 - 6 litres

24
Q

What is serum?

A

substance in blood obtained by the centrifugation of blood from which the clotting factors have been removed

25
Q

What happens to the components of blood if spun in a centrifuge?

A

Plasma/serum found at top
White cells next
Red blood cells at bottom

26
Q

What happens to an erythrocyte after 4 months?

A

Removed from circulation by spleen and liver

27
Q

What is a neutrophil and what is it’s function?

A

Type of granulocyte - contains many granules which are difficult to stain with either basic or acidic dyes
Most common leukocyte
Multi-lobed nucleus

Inactive in circulation, activated by presence of pathogen/inflammation, they move into tissue and act as highly motile phagocytes
Short-lived, production in bone marrow high

28
Q

Describe eosinophils

A

Granulocytes with affinity for red acidic dye eosin
Bilobed nucleus
Slightly larger than neutrophils

29
Q

Describe the function of esosinophils

A

Released from marrow and circulate for 8-12 hours, then move into tissue (especially spleen, lymph nodes, and GI tract) and live there
Their granules contain hydrolytic enzymes
Important in initiation and maintenance of inflammation (allergic reaction, asthma) and fighting parasitic infection

30
Q

Describe basophils

A

Rarest of granulocytes
High affinity for basic dyes such as methylene blue, stains them purple/blue
Bilobed nucleus, often obscured by granules

Granules contain heparin, histamine, and other inflammatory mediators

31
Q

What do basophils do?

A

They are Effector cells during allergic reactions
When a specific allergen binds to their IgE receptors, the granules are released (degranulation)

Leads to allergic reaction eg hayfever, allergic asthma, allergic dermatitis

32
Q

What is the mononuclear phagocyte system?

A

monocytes and macrophages

33
Q

Where are macrophages found?

A

Everywhere but especially in loose connective tissue

34
Q

Describe a monocyte

A

Is an agranulocyte, contain many small lysosomal granules

35
Q

Describe a monocyte

A

Is an agranulocyte, contain many small lysosomal granules
Largest blood cell
Non-lobulated nucleus, nucleus kidney-bean shape

36
Q

Name three members of the mononuclear phagocytic system which do not move around the body

A

Kupffer cells in liver
Microglia in brain
Langerhan’s cells in skin

37
Q

Do lymphocytes contain granules?

A

No, they are agranulocytes

38
Q

Describe the nucleus of a lymphocyte

A

Round

39
Q

What do B and T cells have in common?

A

Appear identical in normal staining, no granules, arise in bone marrow, involved in specific immune response

T cells differentiate in thymus

40
Q

What is the function of a B cell?

A

Produce antibody secreting plasma cells

41
Q

What is the function of a T cell?

A

Defending against infection
Inducing apoptosis
Aiding other immune cells

42
Q

When are the first erythrocytes made?

A

At 3 weeks (within womb) in yolk sac

43
Q

What is hemopoiesis?

A

the production of blood cells

44
Q

During the 2nd trimester, where is most of the blood formed?

A

Liver

Some hemopoeitic cells in spleen

45
Q

After birth, where is the main site of blood production?

A

Bone marrow

Baby - all bones
Adult - Full (Femur) Sleepy (skull) Hippos (hip) Happily (humerus) Rest (rib) Very (vertebrae) Still (sternum)

Marrow in other bones contains adipose cells but can making blood if necessary

46
Q

What are megakaryocytes?

A

Very large cells (30 to 100 micrometers) which produce platelets in bone marrow
Duplicates nuclear material but never divides nucleus/cell - nucleus is huge

Platelets are fragments separated from periphery of cell

47
Q

Where are continuous capillaries found?

A

muscle, nerves, lungs, and skin

48
Q

Where are fenestrated capillaries found?

A

gut mucosa, endocrine glands, and kidneys

49
Q

Where are discontinuous/sinusoidal capillaries found?

A

liver, spleen, and bone marrow

50
Q

Describe the structure of an erythrocyte

A

Biconcave discs, no nucleus and no organelles, 33.3% of volume is haemoglobin

51
Q

How big is an erythrocyte?

A

7 micrometers

52
Q

Why can an erythrocyte squeeze through a gap smaller than itself?

A

Flexible cytoskeleton