Unit 2A Human Form

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Unit 2AHuman Form Function

• Body systems
• Blood

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Study Guide

• Read
• Text Chapter 9
• Complete
• RQ 1-12
• AYK 56

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The circulatory system

• Blood

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Functions of blood

• Transport
• Transports nutrients, oxygen and hormones to the
  tissues.
• Removes wastes such as carbon dioxide and urea.

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• Regulation
• Helps to keep the bodys pH within its
  homeostatic range.
• Helps in regulating the body's temperature.

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• Protection
• Prevents blood loss if blood vessels are damaged.
• Protects the body against pathogens and toxins.

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Features of blood

• Temperature 380C
• pH 7.35-7.45
• Salinity 0.9
• Total body weight 8
• Volume Men 5-6 L, Women 4-5 L

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Composition
1
4
55
40
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Blood plasma

• Plasma is a clear, pale yellow liquid which
  comprises 46-63 of the whole blood
• Plasma consists ofwater (92) dissolved
  organic and inorganic solutes (e.g. sodium
  chloride ions, nutrients wastes) (1)dissolved
  plasma proteins (7)

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Blood cells Number /mm3 Principal function
Red blood cells (Erythro-cytes) 4-6 million Transport of O2 ( some CO2 transport)
White blood cells (Leukocytes) White blood cells (Leukocytes) White blood cells (Leukocytes) White blood cells (Leukocytes)
Granular leukocytes Neutophils 2 000-7 000 Phagocytes
Granular leukocytes Eosinophils 100-400 Phagocytes anti-inflammatory response
Granular leukocytes Basophils 20-100 Inflammatory response
Agranular leukocytes Monocytes 100-900 Phagocytes
Agranular leukocytes Lymphocytes 1 500-3 000 Immune response
Platelets (Thrombo-cytes) 200 000 - 500 000 Blood clotting
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Formed elements
Red blood cells
White blood cells
Blood platelets
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Red blood cells
EM unit / Royal Free Medical School, Wellcome
Images
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White blood cells
Neutrophil
Basophil
Eosinophil
Monocyte
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Clotting of blood
David Gregory Debbie Marshall, Wellcome Images
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Clotting of blood

• A blood clot is a jelly-like mass that forms at
  the site of a wound to stop bleeding.
• A clot consists of a mesh of long, stretchy
  protein fibres, and trapped blood cells.

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• When the clot solidifies it forms a scab.
• If a clot forms inside a blood vessel it forms a
  thrombus.If a thrombus breaks loose it can lodge
  in a vital blood vessel in the heart or brain
  causing a heart attack or stroke.

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The thrombin system

1. Following damage to a blood vessel, blood
   platelets and the injured cells release
   thromboplastin.
2. Thromboplastin interacts with Ca and
   prothrombin (an inactive plasma protein) to form
   thrombin.
3. Thrombin converts finbrinogen (another inactive
   plasma protein) to long, stretchy fibres of
   fibrin.

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The thrombin system

• 4. The fibrin fibres form a mesh at the site of
  the wound, which traps platelets and blood cells.
• 5. Within a few minutes the clot starts to
  contract, which pulls the edges of the broken
  blood vessel together.

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• Serum is the clear yellow fluid that oozes out of
  the clot this is plasma minus the fibrinogen.
• After a couple of days an enzyme in the clot
  activates fibrinolysis - this starts the
  break-down of the clot

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The thrombin system - summary

• Thromboplastin prothrombin Ca thrombin
• Thrombin fibrinogen fibrin
• Fibrin blood cells clot

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The inflammatory response
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The inflammatory response

• Inflammation is the bodys response to harmful
  substances, injury, or irritants.
• Typically the affected area becomes red, tender
  and swollen.

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Stages in the inflammatory response

• When the body is injured, infected or exposed to
  irritants, radiation, or extreme temperatures, a
  complex chemical response is initiated.

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• This response involves several compounds being
  released in the affected area. These substances
  both interact and have specific outcomes (i.e.
  the inflammatory response) e.g. histamine is
  released by mast cells, which causes local
  dilation of the blood vessels and increases mucus
  secretion anti-histamine drugs reverse this
  effect.

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The inflammatory response

• The inflammatory response includes
• Dilation of the blood vesselsin the affected
  area.
• Increased permeability of the capillaries,
  allowing plasma to leak into surrounding
  tissue.
• Chemotaxis phagocytes are attracted to the
  affected area.

Resulting in redness, swelling, heat pain
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The inflammatory response
Site of injury

• Chemical response to injury
• A variety of chemicals released in the affected
  area

• 2. Inflammatory response
• Vasodilation of blood vessels
• Increased permeability of blood vessels
• Chemotaxis