A&P chapter 18 “blood’

Blood components formed elements

Erythrocytes (RBCs)

Leukocytes (WBCs)

Platelets

Erythrocytes (RBCs)

transport respiratory gases in the blood

Leukocytes (WBCs)

defend against pathogens

Platelets

Help form clots to prevent blood loss

Plasma

fluid portion of blood

Contains plasma proteins and dissolves solutes

Centrifuging blood

Withdrawal blood into a syringe and place it into a glass centrifuge tube

Place the tube into a centrifuge and spin for about 10 minutes

Plasma % of blood

55% of blood

Plasma components and % by weight

Water (92%)

Proteins (7%)

Other solutes (1%)

Buffy coat % of blood

Buffy coat components

Platelets (150-400 thousand per cubic mm)

Leukocytes (4.5-11 thousand per cubic mm)

Erythrocytes (44% of body) (4.2-6.2 million per cubic mm)

Leukocytes components and %

neutrophils (50-70%)

Lymphocytes (20-40%)

Monocytes (2-8%)

Eosinophils (1-4%)

Basophils (0.5-1%)

Functions of blood

Transportation

Protection

Body temp

Body pH

Fluid balance

Blood transports

Oxygen, carbon dioxide, hormones, molecules, ions

Delivery system of body

Protection

Leukocytes, plasma proteins-part of immune system

Platelets/blood loss

Body temperature

Blood absorbs heat from body cells (especially muscle)

Heat released at skin blood vessels

Body pH

Contains buffers and maintains pH

Fluid balance

Water is added to blood from GI tract and loss through urine, skin, breathing

Fluid is exchanged between blood and interstitial fluid

Physical characteristics of blood

Color

Volume

Viscosity

Plasma concentration of solutes

Temperature

Blood pH

Color

Depends on degree of oxygenation

Oxygen rich blood is

Bright red

Oxygen poor blood is

dark red

Volume

About 5 liters in adult

On average, males have slightly more than females (due to body size)

Viscosity

Blood is 4-5 times thicker than water

Depends on amount of dissolved and suspended substances relative to amount of fluid

Viscosity increase if

Erythrocyte number increase

Amount of fluid decreases

Plasma concentration of solutes (proteins, ions, etc.)

Determines the direction of osmosis across capillary walls

Ex. During dehydration plasma hypertonic and fluid drawn from tissues

Temperature

Blood is 1degreeC higher than measured body temp

Warms area through which it travels

Blood pH

Is slightly alkaline

PH between 7.35 and 7.45

Crucial for normal plasma protein shape (avoiding denaturation)

Hematocrit

Percentage of volume (erythrocytes, leukocytes, platelets) of all formed elements

Clinical definition of hematocrit

Percentage of only erythrocytes

Hematocrit males percentage

42-56% (males have more RBCs because testosterone causes more secretion by kidney)

Hematocrit female percentage

38-46%

Plasma is composed of

water (92%)

Plasma proteins (7%)

Dissolved molecules and ions (1%)

Is plasma ECF or ISF

ECF it is extracellular fluid

Similar composition to ISF but plasma has higher protein concentration

Blood is a

colloid

Plasma contains

Dispersed proteins

Plasma proteins exert

Colloid osmotic pressure

Plasma proteins exert Colloid osmotic pressure

Prevents loss of fluid from blood as it moves through capillaries

*helps maintain blood volume and blood pressure*

Plasma proteins can be decreased with diseases, resulting in

fluid loss from blood and tissue swelling

ex. Liver diseases that decrease production of plasma proteins

Ex. Kidney diseases that increase elimination of plasma proteins

Variety of plasma proteins

Albumin

Globulins

Fibrinogen

Other clotting proteins, enzymes, and some hormones

Albumin % of plasma proteins

58%

Albumin functions

Exerts osmotic force to retain fluid within the blood

Contributes to blood viscosity

Responsible for some fatty acid and hormone transport

Globulins % of plasma proteins

37%

Globulins functions

Alpha-globulins transport lipids and some metal ions

Beta-globulins transport iron ions and lipids in blood

Gamma-globulins are antibodies that immobilize pathogens

Fibrinogen % of plasma proteins

4%

Fibrinogen functions

Participates in blood coagulation (clotting)

Regulatory proteins % of plasma proteins

Regulatory proteins functions

Consists of enzymes and hormones

Hemopoiesis

Production of formed elements

Hemopoiesis occurs in

Red bone marrow of certain bones

Hemocytoblasts

*stem cells*

Pluripotent

Myeloid line

Lymphoid line

Pluripotent

Can differentiate into many types of cells

Produce two different lines: myeloid line and lymphoid line

Myeloid line

Forms erythrocytes, all leukocytes except lymphocytes, and megakaryoocytes (cells that produce platelets)

Lymphoid line

Forms only lymphocytes

Erythropoiesis makes

erythrocyte

Thrombopoiesis makes

Platelets

Leukopoiesis makes

Granulocytes

Monocyte

B-lymphocyte

T-lymphocyte

Natural killer cell

Erythrocytes (RBCs) lifespan

120 days

Erythrocyte structure

Small, flexible formed elements

Lack nucleus and cellular organelles; packed with hemoglobin

Have bioncave disc structure

* has latticework of spectrum protein providing support and legibility
* Can stay and line up a single file, rouleau

Erythrocyte function

Transport oxygen and carbon dioxide between tissues and lungs

Hemoglobin structure

Red-pigmented proteins

Hemoglobin function

transports oxygen and carbon dioxide

(Facilitates return of carbon dioxide)

(Load oxygen in lungs and release it in tissue)

Oxygenated

When maximally loaded with oxygen

Deoxygenated

when some oxygen is lost

Each hemoglobin molecule is composed of four globins

Two alpha chains and two beta chains

Alpha and beta chains

Eac has a heme group; a porphyrin ring with an iron ion in its center

Oxygen binds to the iron ion, so each hemoglobin can bind four oxygen molecules

How EPO is regulates erythrocyte production

1. Kidney detects decrease in blood oxygen level due to aged erythrocytes, blood loss, exposure to high altitudes
2. Kidney cells release EPO into the blood
3. EPO reaches red bone marrow and stimulates myeloid cells to increase the rate of production of erythrocytes
4. Increased number of erythrocytes enter the circulation during which time the lungs extenuated erythrocytes and blood oxygen levels increase (negative feeedback)

Blood doping

Used by some athletes to enhance performance

One method of blood doping is self donation of erythrocytes

Blood removal prior to competition increases EPO production

Erythrocytes transfused back prior to competition

Second blood doping method; pharmaceutical EPO

used for kidney failure, chemotherapy, and other conditions involving red blood cell loss and anemia

Dangers of blood doping

Increases blood viscosity

Heart required to work harder

May cause permanent cardiovascular damage

Banned from athletic competition

Polthycemia vera

Too many RBCs

Steps for breakdown of hemoglobin

1. Aged erythrocytes broken down into their 3 components in the liver and spleen
2. Bilriubin transported by albumin in the blood
3. Bilirubin removed from blood by liver
4. Bile (containing bilirubin) excreted into small intestine
5. Bilirubin converted to urobilinogen in small intestine
6. Most urobilinogen is converted to stercobilin in the large intestine and expelled in feces

6b. Some urobilinogen reabsorbed into the blood converted to urobilin and excreted in urine

Liver and spleen (breakdown of hemoglobin)

Hemoglobin removed from erythrocyte.

Heme group released from hemoglobin is converted within macrophages first into biliverdin

Biiverdin is eventually converted

into a yellowish pigment called bilirubin within the macrophages

Blood (hemoglobin breakdown)

Bilirubin is then released into the blood and is transported by albumin to liver

Liver (hemoglobin breakdown)

Bilirubin is removed from the body by the liver into small intestine as component of bile

(Jaundice)

Jaundice

Accumulation of bilirubin within the body

Small intestine (hemoglobin breakdown)

Bilirubin is converted within the small intestine into urobilinogen

Small and large intestine (hemoglobin breakdown)

Urobilinogen can continue through small intestine to large intestine and eventually be converted by the intestinal bacteria to stercobilin

Stercobilin

Brown pigment that is expelled from the body as a component of feces

Blood and kidneys

Urobilinogen can be absorbed back into the blood and converted to urobilin

Urobilin

Yellow pigment that is excreted by the kidneys

Clinical view of anemia

Either the percentage of erythrocytes is lower than normal or the oxygen carrying capacity is reduced

Anemia symptoms

Lethargy, shortness of breath, pallor, palpitations

Anemia causes

Decreased or abnormal erythrocyte formation

Heavy blood loss

Deficiency of iron, vitamin B12 or folic acid

Genetic defects

How can some cases of anemia be treated

By pharmaceutical EPO

Sometimes anemia could be an underlying problem like

Stomach ulcer, colon cancer, menstrual cycle heavy

Hypoplastic anemia

Reduced erythropoiesis

Aplastic anemia

No erythropoiesis

Decrease formation of erythrocytes and hemoglobin

Aplastic anemia result from

Defective bone marrow; from poisons, toxins, radiation

Congenital hemolytic anemia

Destruction of erythrocytes more rapid than normal

Congenital hemolytic anemia due to

Genetic defect; produces abnormal membrane proteins that make erythrocyte plasma membrane fragile

Erythroblastic anemia (beta thalassemia)

Hereditary disease → person inherits gene mutation that affects hemoglobin production (abnormal hemoglobin production)

Large number of immature uncleared red blood cells in blood

Hemorrhagic anemia

Due to heavy blood loss

Hemorrhage caused by chronic ulcers or heavy menstural flow

Pernicious anemia

Progressive anemia of adults caused by failure of body to absorb vitamin B12

Defect in production of intrinsic factor leads to pernicious anemia

People with pernicious anemia must receive

B12 intramuscular or subcutaneous injections

Sickle cell anemia

Autosomal recessive anemia

Occurs when person inherits two copies of sickle cell gene

Hemolysis

Hemolysis

Erythrocytes become sickle shaped at lower blood oxygen concentrations, making then unable to flow through blood vessels/tissues and more prone to destruction

Anemias treating by

Letting red bone marrow replace erythrocytes (use pharmaceutical EPO)

Leukocyte characteristics

Defend against pathogens

Contain nucleus and organelles, but not hemoglobin

Motile and flexible-most not in blood but in tissues

Diapesesis

Chemotaxis