Blood and lymphoid system

Question 1

Outline some key blood components

Answer 1

• RBC around 45% males, 40% females
• WBC (1%)
• Plasma 55% males, 60% females REM plasma mostly water, some protein, electrolytes, other solutes, nutrients, blood gases, regulatory substances (hormones and enzymes) and non protein N substances

Question 2

Outline the appearance of different leukocytes

Answer 2

Granulocytes
- Neutrophils- lobed, pinky faint granules
- Eosinophils- bilobed, red to brown granules
- Basophils (rare)- bi/tri-lobed- dominant purple granules
Granulocytes all in lobed shaped nucleus as cells are in various states of apoptosis

Agranulocytes

• Lymphocytes- large round nuclei with little bluish cytoplasm
• Monocytes- very large sausage shaped nucleus, bluish cytoplasm and no obvious granules

Question 3

Functions of different blood cells

Answer 3

• RBC- blood- transport of O2 and CO2
• Platelets- blood- homeostasis, blood clot formation, repair injured tissue

WBC- primary defence:
Neutrophils- blood, connective tissue, spleen- phagocytose foreign substances and infected cells- before die chuck out their DNA so increasing traffic for bacteria to find theirs
- Eosinophils- Blood and most other tissues- Dampening immune response, allergic reactions/ asthma and defending against (e,g, worm)
- Basophil- blood- release vasoactive substances similar to mast cells in response to allergic reactions and asthma
- Lymphocytes- blood and most other tissues- T lymphocytes orchestrate specific immune defence, plasma cells, memory cells, cytotoxic T cells
- Monocytes- blood- circulating reserve macrophages (not main tissue-specific macrophages)

Question 4

What cells are resident in tissue and not the blood- explain their appearance

Answer 4

Plasma cells- spokes of wheel
Macrophages- very large, oval, light or dented nucleus (may be hard to distinguish own nucleus from that of other cells die to undigested cellular material)
Mast cells - filled with granules- involved in vasodilation, weakening of desmosomes, arrestins to stop defence molecules so can leek out into tissue
But by time prepared often granules leaked out (like basophils)

Question 5

Explain how leukocytes get out of blood

Answer 5

• We see the leukocytes (WBC) adhering to the wall- held by the arrestins- yet getting sloppier with rush of blood
  
  • Leukocytes in transit- name for leukocytes squeezing out of blood vessels- increased with higher pressure of blood
    Hence causing swelling of infected tissues