BLOOD

William Harvey- father of physiology: discovered that blood circulated through

the body in 1628.

Blood..a liquid “tissue”???

How are Tissue Classified ?(AGAIN)

Epithelial- lining or covering and glandular tissue.

Muscle- highly specialized to contract

Nervous- irritability and conductivity

Connective- Connects body parts; Must be living cells surrounded by a matrix. Example: Bone (cells sitting in lacunae in hardened matrix of calcium salts in Collagen fibers)

Blood is considered to be a type of connective tissue. Even though it has a different function in comparison to other connective tissues it does have an extracellular matrix.

The matrix is the

plasma and erythrocytes, leukocytes and platelets are suspended in the plasma.

               

                                                

 

Blood

The only fluid tissue in the human body

Classified as a connective tissueLiving cells = formed elementsNon-living matrix = plasma

Introduction

• Blood, a type of connective tissue, is a complex mixture of cells, chemicals, and fluid.

• Blood transports substances throughout the body, and helps to maintain a stable internal environment.

• The blood includes

• Red blood cells – oxygen carrying cells

• White blood cells – fights infections

• Platelets – assist in the clotting of blood

• Plasma – water, proteins, vitamins, cellular wastes, etc.

• A blood hematocrit is normally 45% cells and 55% plasma.

Red Blood Cells

• Red blood cells (erythrocytes) are biconcave disks that contain one-third oxygen-carrying hemoglobin by volume.

• When oxygen combines with hemoglobin bright red oxyhemoglobin results.

• Deoxygenated blood (deoxyhemoglobin) is darker.

• Red blood cells discard their nuclei during development and so cannot reproduce or produce proteins.

• Typical Red Blood cell counts (Approx. 5 million per drop)

• 4,600,000 - 6,200,000 cells per mm3 for males

• 4,500,000 - 5,100,000 cells per mm3 for females.

• The number of red blood cells is a measure of the blood's oxygen carrying capacity.

• The average life span of a red blood cell is 120 days.

• The number of red cells is held relatively constant by the hormone erythropoietin (produced by kidneys)

Control of Erythrocyte Production

Rate is controlled by a hormone (erythropoietin)

Kidneys produce most erythropoietin as a response to reduced oxygen levels in the blood

Homeostasis is maintained by negative feedback from blood oxygen levels

Control of Erythrocyte Production: Homeostasis

Figure 10.5

Hypoxia

Prolonged oxygen deficiency due to deoxyhemoglobin (red blood cells not binded to O2) leads to cyanosis

White Blood Cells • White blood cells (leukocytes) help defend the body against

disease.

• Normally a milliliter of blood contains 5,000 to 10,000 white blood cells.

• There are five types of white cells that can be distinguished by physical features.

1. Neutrophils have fine cytoplasmic granules and a multi-lobed nucleus when red staining • They comprise 54-62% of leukocytes.• Ingest and destroy bacteria

2. Eosinophils have coarse granules that stain deep red, a bi-lobed nucleus, • 1-3% of circulating leukocytes.• Control allergic reactions by removing chemicals

Neutrophil – multi-lobed nucleus. Fine cytoplasmic granules

Eosinophil –cytoplasmic granules when red stained

3. Basophils have fewer granules that stain blue• Fewer than 1% of leukocytes.• Release heparin and histamine, which

increases blood flow• Cause body’s response to allergens.

4. Monocytes are the largest blood cells, have variably shaped nuclei

• Make up 3-9% of circulating leukocytes.

• Can engulf and kill larger invading objects

5. Lymphocytes are long-lived, have a large, round nucleus,

• 25-33% of circulating leukocytes.

• Important for production of antibodies.

Monocyte – kidney, oval, or lobe shaped nucleus.

Lymphocyte – large round nucleus.

Blood Plasma

• Plasma is the clear, straw-colored fluid portion of the blood.

• Plasma is mostly water (90+%) but contains a variety of substances.

• Plasma functions to transport nutrients and gases, regulate fluid and electrolyte balance, and maintain a favorable pH.

• Plasma proteins fall into three groups

1. The albumins help maintain the osmotic pressure of the blood and account for 60% of the plasma proteins.

2. The globulins, comprising 36% of the plasma proteins, are designated as alpha, beta, and gamma globulins.

• Alpha and beta globulins transport lipids and fat soluble vitamins

• Gamma globulins are a type of antibody

3. Fibrinogen (4%) plays a primary role in blood coagulation.

• Plasma also carries oxygen and carbon dioxide.

• Oxygen is carried in low levels in the plasma but mostly by the red blood cells.

• Carbon dioxide is carried in the plasma as carbonic acid.

• Additionally, there are molecules called lipoproteins that help transport lipids throughout the bloodstream

• Chylomicrons – transport dietary fats from small intestine

• VLDL – transport triglycerides from liver to adipose tissue

• LDL – Delivers cholesterol to cells (Considered to be “Bad” cholesterol.)

• HDL – transports broken down chylomicrons to liver. (Considered to be “Good” cholesterol.)

Hemostasis

• Hemostasis refers to the stoppage of bleeding.

• Following injury to a vessel, three steps occur in hemostasis:

1. Blood vessel spasm

• Roughly cutting a blood vessel causes the muscle in its walls to contract in a reflex, or engage in vasospasm.

2. Platelet plug formation

• Platelets stick to the exposed edges of damaged blood vessels, forming a net.

• A platelet plug is most effective on a small vessel.

3. Blood coagulation

• A variety of chemicals and proteins are used to form a clot

ABO Blood Group• This refers to the type of antigens and antibodies found in the

blood stream.

• It allows doctors to determine what type of blood to give if a transfusion is necessary.

• The wrong blood can cause agglutination in a patient leading to death.

• Antigens – molecules on the outer surface of the cell

• Antibodies – molecules floating in plasma that help fight infections.

• Type O is most common (47%) and has no antigens but both A and B antibodies

• Type A is next (41%) and has A antigens and B antibodies.

• Type B follows (9%) and has B antigens and A antibodies.

• Type AB is least common (3%) and has A and B antigens and no antibodies.

Phenotypes

Genotypes

Type A AA, Ao

Type B BB, Bo

Type AB AB

Type O oo

Was Charlie Chaplin the father?

• In 1944 the actress Joan Barry (blood group A) sued Charlie Chaplin (blood group O) for support of her child (phenotype B).

• The blood group evidence was presented in court.

• The jury supported Joan Barry’s claim. Were they right?

The mother must be Heterozygous A (Ao)

The child must be Heterozygous B (Bo, inheriting the “o” from mother)

The child must have inherited a “B” from the father.

Charlie Chaplin was Homozygous O (oo) and therefore could not have been the father.

?

• The Rh factor on blood refers to the positive or negative part of the blood type.

• Rh+ blood has an extra molecule on the blood cell.

• Rh- blood does not have this extra molecule.

• It can lead to problems like erythroblastosis fetalis

• Occurs when an Rh- woman and an Rh+ man conceive a child.