Blood (10) Flashcards

1
Q

How does blood move through the heart?

A

1) Blood leaves heart through arteries which branch into arterioles which branch into capillaries
2) O2 and nutrients leave blood by diffusing across capillary walls to tissues and CO2 moves from the tissues into the bloodstream
3) O2 deficient blood then leaves capillaries and flows into veins which branch into venules which then return this blood to heart
4) Blood flows from heart to lungs to be oxygenated and then returns to heart again

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2
Q

What side of the heart does oxygenated blood flow?

A

Left

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3
Q

What side of the heart does oxygenated blood flow?

A

Left

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4
Q

What side of the heart does deoxygenated blood flow?

A

Right

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5
Q

What is the blood composed of?

A

> It’s the body’s only fluid tissue
It’s a specialised connective tissue in which living blood cells (formed elements) are suspended in a non-living fluid called plasma
Formed elements include; erythrocytes, leucocytes and thrombocytes

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6
Q

What are the characteristics of blood?

A

1) Sticky opaque fluid with a metallic taste
2) Colour varies depending on oxygenation- scarlet= O2 rich, dark red= O2 poor
3) Denser than water and 5x more viscous (because it contains formed elements)
4) Slightly alkaline (pH 7.35-7.45)
5) 8% of TBW
6) Males 5-6L, females 4-5L

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7
Q

Functions of blood- distribution

A

> Delivers O2 from lungs and nutrients from digestive tract to all body cells
Transports metabolic waste products from cells to sites of elimination e.g. lungs to eliminate CO2, kidneys to eliminate waste in urine.
Transports hormones from endocrine organs to target organs

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8
Q

Functions of blood- regulation

A

> Maintains body temp absorbing and distributing heat throughout body
Maintains pH in tissues- bloodborne proteins act as buffers to stabilise pH
Maintains fluid volume- plasma proteins prevent excessive fluid loss from bloodstream into tissue spaces

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9
Q

Functions of blood- protection

A

> Prevents blood loss- when vessels damaged, platelets and plasma proteins initiate clot formation, stopping blood loss
Prevents infection- Antibodies, complement proteins and white blood cells help to protect body from bacteria and viruses

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10
Q

What is blood plasma?

A

> Straw-coloured, sticky fluid
90% water and over 100 different dissolved substances:
1) Proteins- albumin, globulin, clotting proteins
2) Nonprotein nitrogenous substances- lactic acid, urea, creatine
3) Nutrients- glucose, carbohydrates, amino acids
4) Electrolytes- sodium, potassium, calcium, chloride, bicarbonate
5) Respiratory gases- O2 and CO2

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11
Q

What are the 3 formed elements?

A

1) Erythrocytes (not true)
2) Leucocytes (complete cell)
3)Thrombocytes (not true)
> Erythrocytes not true cells as have no nuclei/organelles and thrombocytes are not true cells as they are only cell fragments
> Have short shelf-life (some only few days)
> Most blood cells don’t divide, instead stem cells in red bone marrow continuously divide to replace them

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12
Q

What are erythrocytes?

A

> Most abundant (99%)
7.5um diameter
Biconcave discs
Anucleate
Contain bags of haemoglobin- a protein which has functions in gas transport
Contains the protein spectrin- a deformable network which allows erythrocytes to change shape
Small size and shape provides huge SA for gas exchange
Do not consume any O2 that they carry as they don’t have mitochondria- very efficient
Major contributing factor to viscosity
Male= 4.7-6.1 million/L female= 4.2-5.4 million/L
Haemoglobin binds easily and reversible to O2 and carries most of the O2 in the bloodstream
Lifespan= 100-120 days
As they age, become rigid and fragile and haemoglobin begins degenerating
Dying ones engulfed by macrophages- haem and globin seperated
Female Hb= 11.5-16.5 g/100ml blood
Male Hb= 13-18 g/100ml blood

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13
Q

What is anaemia?

A

> Insufficient erythrocytes
Reduction in O2 carrying capacity of blood
Haemorrhagic anaemia= result of actuate/chronic blood loss
Haemolytic anaemia= Prematurely ruptures erythrocytes
Aplastic anaemia= destruction/inhibition of red bone marrow
Sickle cell anaemia= Abnormally shaped erythrocytes which stick together and form clots

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14
Q

What are the functions of leucocytes?

A

1) Defence against infection
2) Immunity
3) Antigen-antibody reactions
4) Allergies
5) ABO blood grouping
6) Graft versus host disease- when body recognises own cells as foreign

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15
Q

What are leucocytes?

A

> White blood cells
The only formed element that is a complete cell (has a nucleus and organelles)
Less than 1% of blood volume
Defend body against bacteria, viruses, parasites, toxins and tumour cells
Can leave bloodstream by diapedesis (through walls of blood vessels)
2 types- granulocytes (neutrophils, eosinophils and basophils) and agranulocytes (monocytes and lymphocytes)

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16
Q

What are neutrophils?

A

> Granulocytes
‘neutral loving’
Most abundant WBCs
Numbers increase massively during bacterial infections e.g. meningitis
Chemically attracted to sites of inflammation and are active phagocytes
diagram

17
Q

What are eosinophils?

A

> Granulocytes
‘red acid loving’
Active against parasitic worms e.g. flatworms (tapeworms) and roundworms (pinworms)
Play comp,ex roles in allergies and asthma- important modulators of immune response
diagram

18
Q

What are basophils?

A

> Granulocytes
‘base loving’
Cytoplasm contains histamine- an inflammatory chemical that acts as a vasodilator and attracts other WBCs to inflamed area
Antihistamine drugs counter this action
diagram

19
Q

What are lymphocytes?

A

> Agranulocytes
Large numbers in the body but few in the bloodstream
Named after lymph tissue with which they are closely associated
T lymphocytes (T cells)- act directly against virus infected cells and tumour cells
B lymphocytes (B cells)- Give rise to plasma cells which produce antibodies that are released into blood
diagram

20
Q

What are monocytes?

A

> Agranulocytes
When monocytes leave the bloodstream and enter tissues, they differentiate into highly mobile macrophages with ‘big appetites’
Highly phagocytes and important in body’s defence against viruses, intracellular bacterial parasites and chronic infections e.g. TB
Important in activating lymphocytes to mount immune response
Live for several months
diagram

21
Q

What is leukaemia?

A

> Literally means ‘white blood’
Refers it a group of cancerous conditions involving overproduction of abnormal WBCs
Most serious acute forms primarily affect children
Chronic leukaemia occurs more often in the elderly
Fatal without therapy
Bone marrow becomes totally occupied with malignant leucocytes, producing large numbers of non-functional leucocytes
Death caused by internal haemorrhage and overwhelming infections
Treatment= irradiation, antileukaemic drugs and bone marrow transplant

22
Q

How are human blood groups determines?

A

> Red blood cell membranes have proteins called antigens on their external surface and these antigens are;
1) Unique to individual
2) Recognised as foreign
3) Promote agglutination (clotting) and referred to as agglutinogens
4) Presence/absence of these antigen classifies blood grouping
5) Humans have 30 varieties of naturally occurring RBC antigens- ABO and Rh blood groups cause vigorous reactions when transfused to someone from a different group
Blood groups m, N, Duffy, Kell and Lewis mainly used for legal reasons

23
Q

What is haemolytic disease of the newborn?

A

> Antibodies of a sensitised Rh- mother cross the lace at and attack and destroy the RBCs of a Rh+ baby
Rh- mother becomes sensitised when Rh+ blood (from previous pregnancy of Rh+ baby/blood transfusion) causes her body to produce Rh+ antibodies
Drug called RhoGAM can help prevent mother from becoming sensitised
Treatment of haemolytic disease involves pre-birth transfusions and exchange transfusions after birth

24
Q

What are platelets?

A

> Not whole cells, they are fragments of cytoplasm of a larger cell
Essential for clotting cascade
Anucleate
Age quickly and degenerate in about 10 days if not being used in clotting process
Haemophilia- hereditary bleeding disorders;
- Haemophilia A= deficiency of factor V111
- Symptoms begin in early life, even minor trauma causes prolonged and potential life threatening haemorrhaging into tissues and joints