Introduction into the structure and function of blood Flashcards Preview

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Flashcards in Introduction into the structure and function of blood Deck (24)
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1
Q

What are the components of the blood?

A
  1. Plasma (fluid)

2. Cells including RBCs, WBCs and platelets

2
Q

What happens when you centrifuge the blood?

A

From the top, you get plasma (fluid), buffy coat (white cells), Red cells (RBCs and platelets).

3
Q

Describe the basic features of RBCs and their dimensions

A
  • Biconcave discs

* No nucleus and do not contain DNA, RNA or mitochondria

4
Q

What are the most common WBC (leukocytes)?

A
  • Neutrophils

* Lymphocytes

5
Q

Describe polymorphonuclear and granulocytes, and other types of granulocytes

A

• Polymorphonuclear
Irregular, multi-lobed nucleus
having a nucleus with several lobes and a cytoplasm that contains granules, as in an eosinophil or basophil.
• Granulocyte
prominent cytoplasmic granules
i.e. a neutrophil, basophil, or eosinophil.
• People often say “granulocytes” or “polymorphs” when they mean neutrophils
• However, there are two other types of granulocyte:

6
Q

Describe Mononuclear cells

A

• Lack granules
• Large, regular nuclei
• Two types:
Monocytes and Lymphocytes

7
Q

Give a brief overview of platelets

A
  • Cytoplasmic fragments
  • No nucleus
  • Membrane bound
  • Contain granules
8
Q

Where do Red blood cells come from?

A
  • Mature blood cells are produced from stem cells in the bone marrow
  • Bone marrow contains many immature cells
  • Some blood diseases can be treated by bone marrow transplantation
9
Q

What does the plasma fluid contain?

A
•	fluid containing
 	water
 	salts
 	proteins
 	organic molecules e.g.
	metabolites
	carbohydrates
	lipids
10
Q

What ions are present in the blood?

A

• Positive ions (cations)
sodium (Na+)
Also potassium, calcium, magnesium and hydrogen ions
• Negative ions (anions)
Chloride (Cl-)
Also bicarbonate, phosphate, sulphate & organic anions

11
Q

Describe serum and plasma

A
  • Plasma is the fluid component of whole blood
  • Serum is the fluid left after blood clotting

• Some blood tests require unclotted blood
Use anticoagulant e.g. EDTA
• Other tests work better with serum than plasma

12
Q

Describe Plasma proteins (3)

A
  • Normal: 7-9% of plasma is protein
  • Complex- thousands of different proteins
  • But > 90% is a single protein: albumin
13
Q

What are the functions of the blood?

A

• TRANSPORT
Carry oxygen / nutrients to tissues
Remove CO2 / other waste products from tissues
Transport other substances (e.g. hormones) from sites of production  sites of action
• DEFENCE
• HOMEOSTASIS

14
Q

What do erythrocytes do?

A

• Transport oxygen from lungs  body tissues
• Help in removal of CO2 from body tissues  lungs
Most CO2 carried as bicarbonate in plasma
Red cell enzyme carbonic anhydrase helps CO2
 to dissolve in plasma from the tissues
 Come out of solution in the lungs
• Major constituent is the protein haemoglobin (Hb)
• Hb binds oxygen
• Carries it from the lungs to the tissues

15
Q

Describe Haemoglobin

A

• Haemoglobin is a protein tetramer made up of 4 polypeptide chains-
2 alpha globin chains
2 beta globin chains
• Each globin chain carries a haem molecule
• The haem holds a ferrous (Fe++) iron atom.
• Oxygen binds reversibly to the iron atom by a coordination bond.
• Oxyhaemoglobin
Fully saturated with O2 = bright red
• Deoxyhaemoglobin
Lost all O2 = dark red
• Basis of pulse oximetry, Measures the colour of the haemoglobin, Determines if patient is hypoxic
• There are about 300,000,000 Hb molecules in each RBC
• Very high concentration
• Almost 50% of the space in a red cell is taken up by Hb

16
Q

what are the functions of plasma proteins?

A

• Plasma proteins carry substances which are poorly soluble in water e.g.
lipids
lipid soluble hormones and vitamins
• Plasma proteins also carry metal ions e.g.
Ca++
Fe++
Cu++

17
Q

Describe defence as a function of the blood

A
•	DEFENCE
 	Immunity
	WBC and plasma proteins
 	Clotting (aka haemostasis)
	Platelets and plasma proteins
18
Q

Describe the function so each of the WBCs

A
White Blood Cells (WBCs) 
•	Neutrophils
 	Phagocytose and kill bacteria & fungi
 	Main mediators of innate immunity
•	Lymphocytes
 	Main mediators of adaptive (acquired) immunity
 	Produce antibodies
 	Kill virus infected cells
Other White blood cells 
•	Eosinophils
 	Kill parasites
 	Involved in allergic responses
•	Basophils 
 	Kill parasites
 	Involved in allergic responses
 	Involved in inflammation
•	Monocytes (macrophages)
 	Phagocytosis of dead cells and pathogens
19
Q

What do Immunoglobulins (Ig) do and Complement proteins do?

A
•	Immunoglobulins (Ig) 
 	Made by B-lymphocytes
 	Act as antibodies against pathogens
•	Complement proteins
 	kill bacteria and other pathogens
 	cooperate with Ig and WBC
20
Q

What is the function os platelets?

A

• Major role: Primary Haemostasis
Recognise damage at the blood vessel wall
Form a platelet plug
Prevent/stop bleeding
• Platelet plug stops bleeding– but insecure & temporary.

21
Q

Describe fibrinogen (4)

A
  • Fibrinogen is a major plasma protein
  • Converted to Fibrin, forms a blood clot
  • Clotting factors control process
  • Fibrin clot reinforces primary platelet plug
22
Q

Describe homeostasis as a function of the blood in further detail

A
•	HOMEOSTASIS- keeping the internal environment of the body constant
 	Maintaining pH (7.4)
 	Controlling distribution of water and solutes
 	Distributing heat
 	Plasma pH, ion concentrations and protein concentrations must be kept within safe limits
 	Otherwise bad things happen
•	Disturbed by disorders of:
 	Kidney
 	Liver
 	Lungs
 	Cardiovascular system 
 	Endocrine organs
23
Q

Describe the blood in numbers

A

On image

24
Q

Discuss the types of blood tests that can be carried out

A

Full blood count (FBC) which determines the concentration of haemoglobin in the blood, used to diagnose anaemia. This also includes the full white blood cell count, no of neu and lym - important for disease

Mean Red cell Volume (MCV) used to calculate the size of RBCs.

Mean Red cell haemoglobin count (MCHC) used to calculate the number of haemoglobin molecules in each red cell to diagnose the type of anaemia.