Blood

Functions

• Carries O2, hormones, and nutrients to the body tissues

• Helps to remove CO2 and other wastes from the body

• helps to regulate and distribute body heat

• Helps protect against infection

• Clotting to prevent excessive bleeding from the wound

Composition

• Plasma (55%)

• Erythrocytes (RBC’s)

• Leukocytes (WBC’s)

• Thrombocytes (platelets)

Erythrocyte• Red blood cell (35 trillion)

• Primary function to carry oxygen to all of the cells.

• RBC formation (erythropoiesis) in adults takes place in the bone marrow

• Average life span 120 days

• As they become fragile they are removed by macrophages in the liver, spleen and bone marrow.

Leukocyte• White blood cell (lifespan 9 days)

• Primary effector cells against fighting infection and tissue damage.

• Neutralize and destroy organisms

• act as scavengers clean up damaged cells by phagocytosis to initiate the repair process

• Normal WBC count 5,000 to10,000/mm3

• Differential count: measures % of each type of WBC

Thrombocytes

• Platelets

• 130,000 to 400,000 mm3

• Play an important role in blood coagulation, hemostasis, and blood thrombus formation

• when a small vessel is injured, platelets adhere to each other and form a clot

• Can be beneficial or harmful (ex. Includes coronary occlusion)

Plasma• Liquid part of lymph and blood

• consists of serum, protein and chemical substances like electrolytes, glucose, and proteins

• Serves as a medium for transporting these substances to various structures and at the same time transporting waste products to various sites of clearance

• thin and colorless

Types

• A- 40%

• B- 11%

• AB-4% Universal Recipient

• O- 45% Universal donor

Reasons for blood transfusions

• To replace blood lost through hemorrhage

• to treat anemia

• To treat shock

• To exchange blood in certain disorders

• To aid recovery as a preoperative or postoperative procedure

BLOOD TYPE DONATE TO RECEIVE FROM

A A or AB A or O

B B or AB B or O

AB AB A, B, AB, O

O A, B, AB, O O

Rh Factor

• Red Blood Cell Protein

• 85% of population have protein and are +

• 15% are Negative

• When Rh = blood given to a neg blood antibodies are formed and positive blood is destroyed.

• Negative blood can be given to positive

Rh Factor and Pregnancy

• An Rh negative mother may become sensitized by proteins from an RH positive baby (inherited from the father)

• During pregnancies following the sensitization, the mother’s antibodies may pass into the blood of the unborn infant and cause erythroblastosis, a destruction of RBC’s

Innovations in Blood Transfusion

• Autologous transfusion – collection and transfusion of a person’s own blood

• Interoperative salvage – collecting and returning a person’s own blood

• Apheresis – donated blood is separated into parts using a centrifuge. (before apheresis, platelets for one transfusion required 5-10 donors)

Functions of Lymph and Lymphatic Tissue

• Maintains fluid balance

• Immunity

What is lymph?

• A watery substance formed from fluids that filters into the body tissues or interstitially.

• The fluid is returned to the body through the lymph vessels

• Lymph capillaries are more porous than blood capillaries, allowing fluid in the tissues to collect and be returned to the circulatory system

What are the lymphatic tissues

• Tonsils

• Thymus

• Spleen

• Nodes

• Lymph vessels

IMMUNITY

• Non-specific or innate

• Specific– Acquired – Inherited

Non-Specific or InnateImmune Response

• Includes the barrier of the skin, mucous membranes, tears and leukocytes

• Types of non-specific defense– Localized Inflammatory Response– Systemic Inflammatory Response

Specific Immunity

• Inherited– Genetic trait (e.g., humans can’t get some

diseases that affect dogs)

• Acquired– Natural: caused by exposure to the agent

unintentionally (maternal antibodies transmitted via breast milk)

– Artificial – obtained intentionally (e.g., vaccination)

Common Assessment techniques

• Direct Examination

• Chemical Tests

• Coagulation Studies

Direct Examination

• Hemoglobin test (Hgb)

• Hematocrit (Hct)

• Sedimentation

• Reticulocyte studies

• Platelet or Thrombocyte count

• Aspiration biopsy cytology

Chemical Tests

• Use spectrophotometry – calculates the concentration of substances in solution by measuring the amt of light it absorbs

• Examples: Complete Blood Count (CBC) and Sequential Multiple Analysis (SMA)

Coagulation Studies

• Bleeding Time – amt of time an incision takes to clot

• Prothrombin time (PT) uses an anticoagulant to measure the blood sample’s clotting time