Circulatory System; BloodChapter 18, pg 679

Blood clot showing Red

blood cells in a fibrin mesh

The basics, functions and properties

• People have 4-6 L of blood• Two components include

– Plasma: clear fluid– Cells & Platelets

• Erythrocytes (RBCs)• Leukocytes (WBCs)

• Centrifuging blood separates the two parts– RBCs make up ~ 45% of volume, a number called the

hematocrit– RBCs make blood 4xs as viscous as water

Blood Components• This test tube

shows the components of blood in their relative ratios. It shows a hematocrit of 45. The RBC layer together with the "buffy coat" layer make up 45% of the total volume of centrifuged blood (4.5 m. out of 10 ml).

• hematocrit of a normal adult male : 47 adult female: 42

Plasma

• Serum: Like plasma but, without clotting proteins

• Proteins of Plasma– Albumins: smallest & most

abundant• Regulates osmotic pressure

– Globulins: alpha, beta, and gamma

• make up antibodies

– Fibrogen: allows clotting• Nitrogenous wastes in plasma

(urea) are excreted in the kidneys

Erythrocytes (RBCs)

• O2 & CO2 carrier

• Determine bloodtype• Need to be resilient to

get through capillaries• Hemoglobins make up

33% of the cytoplasm• Nucleus is lost during

cell formation

Qualities of Erythrocytes

• RBC count (Hematocrit) tells how much O2 blood carries

• Why women have lower hematocrits– Androgens stimulate RBC

production– Menstrual loss– Inverse proportion to body fat– Males also clot faster. – What evolutionary significance

might this have?

Erythrocyte Disorders

• Polycythemia: Excess RBC

• Anemia: RBC Shortage

• Sickle Cell: ~1.3 % of African Americans– Symptoms: aches in

joints from clogged capillaries, some associated symptoms can be fatal

Blood Types

• Antigens on RBC surface allow antibodies to recognize what is and what is not us

• ABO blood group is a multiple allele explanation of blood types

The ABO Blood grizzoup

Type O Type A Type B Type AB

Genotypes Ii IA IA, IAi IB IB, IB i IA IB

RBC Antigen None A B A, B

Plasma Antibody

Anti-A, Anti-B

Anti-B Anti-A None

Compatable Donors

O O,A O,B O,A,B, AB

Blood Compatibility

• Agglutination happens when antibodies attack foreign RBCs

• AB is called the universal recipient because it has no RBC antibodies– But the donors Antibodies can

attack the recipients– Also one of the rarer blood types

• O is the universal donor

Rh Groups

• Named for Rhesus Monkey

• 3 genes, C, D, and E, each with two alleles

• DD, or Dd have D antigens on RBCs,– Classified as Rh+ – Rh- lack D antigens

• Combined with ABO group to get Blood types like A positive or B negative

Rh Transfusion problems

• If Rh- person recieves Rh+ blood– First one is okay, the body hasn’t made any Anti-D

antibodies– Second one can cause problems

• With fetuses with different Rh groups– The pregnancy is fine as long as there is no tearing of

the placenta– Then the baby might be born with Hemolytic disease

of the new born (HDN), a type of anemia

Other Blood groups

• ~100 others, and ~500 antigens– MN, Duffy, Kell, Kidd,

and Lewis groups

• Rarely cause transfusion problems

• Useful in paternity cases

Leukocytes

• White blood cells

• Have nuclei– Different types are

noted by shape of nucleus

– Grainy appearance when stained

WBCs

Neutrophils• Make up the largest %

of WBCs• Releases antimicrobial

chemicals• A high count is a sign

of bacterial infectionLymphocytes• About 1/3 of WBCs• Fights foreign bodies• Secretes antibodies

Leukemia• Leukemia is cancer of the blood cells. • body produces large numbers of abnormal

WBCs• Symptoms

– Fever, chills and other flu-like symptoms – Weakness and fatigue – Loss of appetite and/or weight – Swollen or tender lymph nodes, liver or spleen – Easy bleeding or bruising – Tiny red spots (called petechiae) under the skin – Swollen or bleeding gums – Sweating, especially at night – Bone or joint pain

• Treatments– Chemotherapy– Radiation therapy– Antibody therapy– Bone Marrow Transplants

Also a feline variant