Unit 2A Human Form & Function Body systems Blood Body systems Blood

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

The circulatory system Blood

Functions 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 blood Temperature 38 0 C pH Salinity 0.9% Total body weight 8% Volume Men 5-6 L, Women 4-5 L Temperature 38 0 C pH Salinity 0.9% Total body weight 8% Volume Men 5-6 L, Women 4-5 L

Composition ~55%~40% ~4% ~1%

Blood 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 cellsNumber /mm3 Principal function Red blood cells (Erythro- cytes) 4-6 millionTransport of O 2 (& some CO 2 transport) White blood cells (Leukocytes) Granular leukocytes Neutophils Phagocytes Eosinophils Phagocytes & anti- inflammatory response Basophils Inflammatory response Agranular leukocytes Monocytes Phagocytes Lymphocytes Immune response Platelets (Thrombo- cytes) Blood clotting

Formed elements Red blood cells White blood cells Blood platelets

Red blood cells EM unit / Royal Free Medical School, Wellcome Images

White blood cells NeutrophilBasophil EosinophilMonocyte

Clotting of blood David Gregory& Debbie Marshall, Wellcome Images

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. 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 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. 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 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 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

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

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.

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 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 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