CHAPTER 18 done

Arteries

Blood vessels that carry blood AWAY from the heart.

Veins

Blood vessels that return blood TOWARDS the heart.

Capillaries

Microscopic blood vessels formed between arteries and veins that serve as sites for exchange.

Blood composition

Formed elements + plasma

Formed elements

Erythrocytes + leukocytes + thrombocytes

45% of whole blood

Erythrocytes

Red blood cells (RBCs) present at normal values of 5–6 million cells/µL of blood in males and 4–5 million cells/µL in females, responsible for oxygen and carbon dioxide transport.

Leukocytes

White blood cells (WBCs) present at normal values of 4,500–11,000 cells/µL of blood that defend the body against pathogens and toxins.

Platelets

Anucleate membrane-enclosed cellular fragments present at normal values of 150,000–450,000 cells/µL of blood that play an essential role in hemostasis.

Plasma

The top liquid layer of centrifuged blood making up ~55% of whole blood, composed of ~92% water, ~7% plasma proteins, and ~1% solutes.

How blood Serves in transportation

Carries oxygen from the lungs to tissues and carbon dioxide From tissues, back to lungs

Transports nutrients from Gastrointestinal tract

Hormones

Transports waste product products to organs such as kidneys and lungs

Heat generated by Metabolically active tissues throughout the body

How blood serves in regulation

Maintain homeostasis by regulating body temperature, pH, balance, and fluid balance

Distributes heat throughout the body and releases Surface

Contains chemical buffers that stabilize, pH and plasma proteins, They maintain automatic pressure and regulate the movement of water between the blood and tissues

How blood serves in protection

Has leukocytes and plasma proteins that defend against pathogens

Platelets and clotting proteins in the plasma work together to form blood clots

Whole blood

Plasma with formed elements

After centrifuge plasma

Rises to the top; 55%

After centrifuge Erythrocytes

Settles in bottom 44%

Buffy Coat

The thin middle layer of centrifuged whole blood (<1% of total volume) containing leukocytes and platelets.

Hematocrit or PCV packed cell volume

Also known as Packed Cell Volume (PCV), it is the percentage of total blood volume occupied by erythrocytes (~44% in normal blood).

Albumins percentage in plasma proteins

58%

Water percentage in plasma

92% by weight

Protein percentage in plasma

7% by weight

other solutes % in plasma

1% Contains electrolytes, nutrients, respiratory gases, and waste products

Globulin percentage in plasma proteins

37%

Fibrinogen percentage in plasma, protein

4%

Regulatory proteins in plasma proteins percentage

Less than 1%

Buffy coat less than 1% of whole blood

Contains platelets, 150 to 400,000 per cubic millimeter

Normal total leukocyte (WBC) count per cubic millimeter

4.5–11,000 per mm3

Percentage of neutrophils in Buffy coat

50–70%

percentage of lymphocytes within Buffy coat

20–40%

Percentage of monocytes within Buffy coat

2–8%

Percentage of eosinophils within Buffy coat

1–4%

Percentage of basso fills within Buffy Coat

0.5–1%

Erythrocytes 44% of whole blood

4.2–6,200,000 per cubic millimeter

Dehydration

A condition causing loss of plasma water, which concentrates RBCs and leads to an increased hematocrit.

Severe sweating, Vomiting, diarrhea, inadequate water intake

Living at high altitude

Low oxygen level stimulate kidneys to release erythropoietin Which increases red blood cell production

People that live in mountains

Increase red blood cell production polycythemia

Excessive production of red blood cells raises the percentage of red blood cells in blood

Causes polycythemia vera such as bone marrow disorder

Chronic low oxygen conditions

Body compensate by producing more red blood cells to carry oxygen

Example is chronic lung disease, some heart disease, smoking

Polycythemia

A condition characterized by excessive bone marrow RBC production, leading to an increased hematocrit.

Hemorrhage/blood loss

Loss of red blood cells, decrease red blood cell volume

such as trauma surgery or internal bleeding

Anemia

Reduce red blood cell number or reduce hemoglobin production

Iron deficiency anemia, vitamin B12 deficiency anemia

Bone marrow disorder

Reduced production of red blood cell

Bone marrow failure, leukemia affect affecting marrow function

Access fluid and blood (hemodilution)

Lack of materials needed for red blood cell production

Iron, vitamin B12, or folate deficiency

causes hematocrit values to be high

When the blood becomes red blood cell rich

What causes hematoma to be low?

When the blood becomes plasma rich or red blood cell poor

Plasma considered an extra cellular fluid

Has similar concentrations of electrolytes, nutrients, and waste products like that of interstitial fluid

colloidal suspension

Blood is considered this because there are proteins floating in plasma

Proteins in blood

Help pull water into themselves through a process called osmosis

Colloid Osmotic Pressure

The osmotic pulling force exerted by plasma proteins (especially albumin) that holds water inside blood vessels.

Albumin

The most abundant plasma protein (~58%) that exerts colloid osmotic pressure to retain blood volume, contributes to blood viscosity, and transports ions, lipids, and hormones.

Edema(Swelling)

When albumin levels decrease, water leaves the blood vessels and collects in the tissues

Functions of plasma protein

Help buffer against changes in blood pH

Maintain osmotic balance and contribute to blood functions

Functions of albumin

Excerpts osmotic force to retain fluid within blood vessels

Helps maintain blood volume and prevents excessive fluid loss into tissues

Contributes to blood Viscosity

Transport selected molecules, such as ions, lipids, and hormones

Globulins

Plasma proteins (~37%) divided into Alpha (transport lipids & ions-copper), Beta (transport lipids & iron ions), and Gamma (antibodies for immune defense).

Fibrinogen

A plasma protein (~4%) essential for blood clotting that converts into insoluble fibrin strands during coagulation.

Hemocytoblasts

Pluripotent stem cells residing in red bone marrow from which all formed elements originate during hematopoiesis.

Regulatory proteins functions

Include enzymes and hormones that regulate various Physiological processes

Third week of embryonic life

Makes blood and yolk sack

First sight for hematopoiesis, produces primitive red blood cells containing embryonic hemoglobin

Six weeks – seven months of fetal life

Liver is major site for hematopoiesis

Liver becomes the primary organ that produce red blood cells, white blood cells, and platelets

3rd–6 month of fetal life

Spleen helps to contribute to formation of hematopoiesis and white blood cells

Fifth month onward

Bone marrow begins and gradually takes over for hematopoiesis

Birth onward

Bone marrow becomes primary site For Hematopoiesis

Hemocytoblast

Hematopoietic stem cell which divides into a myeloid line or lymphoid line

Myeloid Line

The hematopoietic stem cell lineage that forms erythrocytes, megakaryocytes (platelets), granulocytes (neutrophils, eosinophils, basophils), and monocytes.

Lymphoid Line

The hematopoietic stem cell lineage that forms lymphocytes, including B-lymphocytes, T-lymphocytes, and Natural Killer (NK) cells.

Reticulocyte

An immature erythrocyte stage formed after a normoblast ejects its nucleus, which enters circulation and matures into an erythrocyte.

Erythropoiesis

Needs EPO To create progenitor cell, which then becomes a erythrocyte

Thrombopoiesis

Needs thrombopoietin to create platelets

Leukopoiesis

Needs GM – CSF, to create eosinophils, Basophils, neutrophils, Monocytes

Characteristics of Erythrocytes

Unique by concave disc structure

No nucleus or organelles

Respiratory gases are transported by hemoglobin

Plasma membrane encloses 280 million hemoglobin molecules

7.5 micrometer wide

2.6 µm thick on ends

0.75 µm at thinness point

Erythropoiesis characteristic

Rate of production is equal to 3,000,000 per second

Needs iron plus B vitamins plus amino acids

Stimulus is hypoxia(decrease oxygen level in blood)

blood loss/high altitudes

Increases erythropoietin(EPO) Release

Erythropoietin

Hormone needed for erythropoiesis and made from the kidneys 90%

Ribosome producing hemoglobin

Early erythroblast

Late erythroblast

Large nucleated cell

Proerythroblast

Process of Erythropoiesis

Progenitor cell

Proerythoblast

Early erythroblast

Late erythroblast

Normoblast(nucleus ejected)

Reticulocyte

Erythrocyte

How erythropoietin regulates erythrocyte production

1- stimulus: Decrease blood oxygen level levels

2-kidney(receptor)detect decrease blood oxygen

3-Control Center- Kidney cells release EpO into the blood

4-effector-EPO stimulates red bone marrow to increase the rate of production of red blood cells

5-Net effect-Increased numbers of erythrocytes enter the circulation, during which time the erythrocytes are oxygenated and blood oxygen level levels increase

6-Increase blood oxygen levels are detected by the kidney which inhibits EPO released by negative feedback

Hemoglobin Hb

Contains Heme (Iron - Fe2) + Globin chains

Red protein which transport O2+CO2

Oxygenated blood- when hb is maximally loaded with O2

Deoxygenated blood - when hb loses O2 + CO2 bound to globin

Erythrocyte destruction

Cannot repair themselves, live for 120 days

Liver and spleen through macrophages carry out destruction

Fe2+ and globin are recycled back into the body

1st step of erythrocyte destruction

Aged erythrocytes broken down into their three components in the liver and spleen (ironless heme, iron ion, globin)

2nd Step of erythrocyte destruction

Bilirubin transported by albumin in the blood

3rd step of erythrocyte destruction

Bilirubin removed removed from blood by liver

4th step of erythrocyte destruction

Bile(containing bilirubin) excreted into small intestines

5th step of erythrocyte destruction

Bilirubin converted to urobilinogen in small intestine

6th step of erythrocyte destruction

Most urobilinogen is converted to stercobilin in the large intestine and expelled in feces

Some urobilinogen reabsorbed into the blood, converted to urobilin and excreted in urine

Urobilin excreted in urine

blood type antigens(agglutinogens)

Inherited markers made of proteins, sugars, or lipids – located on the surface of red blood cells, determine blood type

ABO system

Classifies blood based on the presence or absence of antigen A and antigen b on the red blood cells

Type AB

Has both Anti-gen A and anti gen B

Type O

Lacks both antigens A and B

RH system

based primarily on the presence of the RhD antigen

blood type antibodies (agglutinins)

The immune system forms antibodies, and the plasma against which ever ABO Blood type antigens are not found on the individuals RBC’s

Blood type AB (antibody)

None

Blood type O( antibody)

Anti A / Anti B

A+

Can donate to A+, AB+

Can receive from A+, A-, O+,O-

A-

Can donate to A+, A-, AB+, AB-

Can receive from A-, O-

AB+

Can donate to AB+

Receive from all blood types

AB-

Can donate to AB+, AB-

Can receive from AB-,A-,B-,O-

B+

Can donate to B+,AB+

Can receive from B+,B-,O+,O-

B-

Can donate to B+,B-,AB+,AB-

Can receive from B-,O-

O+

Can donate to O+,A+,B+,AB+

Can receive from O+,O-

O-

Donates to all blood types and receive only O-

Agglutination

Happens when there is a unsuccessful blood type match, hemolysis

RBCS clump together