Unit 2A

Human Form & Function

Unit 2A

Human Form & Function

Body systems

Blood

Body systems

Blood

Study GuideStudy Guide

Read:• Text Chapter 9Complete:• RQ 1-12• AYK 5&6

Read:• Text Chapter 9Complete:• RQ 1-12• AYK 5&6

The circulatory systemThe circulatory system

BloodBlood

Functions of bloodFunctions of blood

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

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

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

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

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

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

Features of bloodFeatures 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

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

Women 4-5 L

CompositionComposition

~55%~40%

~4%

~1%

Blood plasmaBlood plasma

• Plasma is a clear, pale yellow liquid which comprises 46-63% of the whole blood

• Plasma consists of:water (92%)

dissolved organic and inorganic solutes (e.g. sodium & chloride ions, nutrients & wastes) (1%)dissolved plasma proteins (7%)

• Plasma is a clear, pale yellow liquid which comprises 46-63% of the whole blood

• Plasma consists of:water (92%)

dissolved organic and inorganic solutes (e.g. sodium & chloride ions, nutrients & wastes) (1%)dissolved plasma proteins (7%)

Blood cells

Number/mm3

Principal function

Red blood cells(Erythro-cytes)

4-6 million

Transport of O2 (& some CO2 transport)

White blood cells (Leukocytes)

Granular leukocytes

Neutophils 2 000-7 000

Phagocytes

Eosinophils 100-400 Phagocytes & anti-inflammatory response

Basophils 20-100 Inflammatory response

Agranular leukocytes

Monocytes 100-900 Phagocytes

Lymphocytes

1 500-3 000

Immune response

Platelets(Thrombo-cytes)

200 000 -500 000

Blood clotting

Formed elementsFormed elements

Red blood cellsWhite blood cells

Blood platelets

Red blood cellsRed blood cells

EM unit / Royal Free Medical School, Wellcome Images

White blood cellsWhite blood cells

Neutrophil Basophil

Eosinophil Monocyte

Clotting of bloodClotting of blood

David Gregory& Debbie Marshall, Wellcome Images

Clotting of bloodClotting 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.

• 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.

• 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.

• 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.

The thrombin systemThe thrombin system1.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.

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.

The thrombin systemThe 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.

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.

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

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

The thrombin system - summary

The thrombin system - summary

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

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

The inflammatory response

The inflammatory response

• Inflammation is the body’s response to harmful substances, injury, or irritants.

• Typically the affected area becomes red, tender and swollen.

• Inflammation is the body’s response to harmful substances, injury, or irritants.

• Typically the affected area becomes red, tender and swollen.

The inflammatory response

The inflammatory response

Stages in the inflammatory response

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.

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

• 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.

• 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.

The inflammatory responseThe inflammatory response

The inflammatory response includes:• Dilation of the blood vessels

in the affected area.• Increased permeability of

the capillaries, allowing plasma to leak into surrounding tissue.• Chemotaxis – phagocytes are

attracted to the affected area.

The inflammatory response includes:• Dilation of the blood vessels

in 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

The inflammatory response

The inflammatory response

1. 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

Site of injury