Unit 3

blood

functions of the blood

• Transports nutrients, oxygen, wastes, and hormones

• Helps maintain the stability of internal fluids - Homeostasis

• Distributes heat to get it out of the body

Characteristics of blood

-Is a type of Connective

-Cells are suspended in a liquid extracellular matrix.

-The matrix is the plasma

• Holds all of the cells (RBC, WBC, Platelets) together.

• Heavier than water (3-4 times as much).

• Made up of: 

  • plasma

  • formed elements

The formed elements

• Red blood cells (erythrocytes) 

• White blood cells (leukocytes)

• Blood platelets (thrombocytes)

Hematopoiesis

formation of ALL blood cells (white, red, platelets)

Blood cells are made in…

Red bone marrow

Erythropoiesis

Specifically red blood cell formation

Erythropoietin

Hormone which is released from the kidneys controls the rate of RBC formation.

• When released, triggers body to make more RBC’s.

Characteristics of red blood cells (RBC)

• Average lifespan of a erythrocyte: 120 days

• Tiny, biconcave discs (thicker outer, thinner inner)

• Anucleate

• no mitochondria

Why are RBC shaped the way they are

• Transportation of gases

  • Increases surface area (compared to a regular cell)

  • Places cell membrane closer to hemoglobin (in center)

• Easily pass through narrow passages of capillaries.

Red blood cells are anucleate:

• (lack nucleus) – function of cell simple

Blood volume

• Typically 8% of body weight

• About 5 liters in body

Percentages of blood for hermatocrit, plasma, buffy coat

• Hermatocrit - 45% 

  • Red blood cell count

• _plasma - 55% 

  • Fluid of blood

• __Buffy coat - 1%

  • Platelets

  • White blood cells

Hemoglobin

• is a protein in which oxygen attaches to in a erythrocyte.

• Each erythrocyte is about 1/3 hemoglobin.

When hemoglobin combines with oxygen…

erythrocyte is bright red.

When oxygen is released..

• he resulting erythrocyte is a dull red.

  • May appear bluish when viewed through blood vessels walls.

How can your blood cell count change

-Gender, altitude

-Body goes through positive feedback system to go to homeostasis

Dietary factors that impact RBC production

• Need to have in diet: 

  • Vitamin B12

  • Folic Acid

  • iron

• Influences erythrocyte production.

Anemia

• Deficiency of RBC or reduction in hemoglobin.

• Person appears pale and lacks energy.

• Decrease in hematocrit.

White blood cells

• Called Leukocytes_

• Protect against diseases.

• Blood transports leukocytes to site of infection.

Platelets

• Called Thrombocytes

• Not really a cell, they are cell fragments.

• Help repair damaged blood vessels by sticking to broken surfaces.

• Form blood clot(scab).

• Pus:

  • There to help protect.

Characteristics of plasma

• Plasma is clear.

• 55% of blood (other 45% formed elements)

• Approximately 92% water.

Functions of plasma

• Transports nutrients, gases, and vitamins.

• Help regulate fluid and electrolyte balance.

• Maintain favorable pH.

Albunins

• Smallest of the proteins.

• 60% of all plasma proteins.

• Help regulate water movement between blood and the tissues.

• Thus this helps control blood pressure

Globulins

• 36% of all plasma proteins.

• Transport fats and vitamins.

Fibrinogen

• 4% of all plasma proteins.

• Plays role in blood clotting.

  • Work with platelets.

Gases in plasma

• Most important gases in blood plasma are Oxygen and _Carbon dioxide.

• Nitrogen is also in plasma.

Nutrients in plasma

• Include carbohydrates, fats, proteins.

Electrolytes in plasma

• Ions such as sodium, potassium, calcium, magnesium, and more.

Hormones in plasma

• travel to their target cells in the plasma.

Wastes

• carried out of the body by the plasma. 

Hemostasis

• The stoppage of bleeding.

Three steps to hemostasis

• Blood vessel spasm

• Platelet plug formation

• Blood coagulation

Blood vessel spasm

• Cutting or breaking a smaller blood vessel stimulates the smooth muscles in its wall to contract.

  • Called vasospasm.

• This lessens blood loss as the cut begins to close.

Platelet plug formation

• Platelets come in and adhere to 3 things:

  • To each other.

  • To the end of the broken vessel.

  • To exposed collagen.

Blood coagulation

• The major event in blood clot formation is conversion of the blood plasma protein fibrinogen into threads of protein called fibrin.

• Fibrin stick to exposed surfaces of damaged blood vessels.

• Creates meshwork that entraps blood cells and platelets.

• Thus it makes a blood clot.

Blood clotting is a example of..

Positive feedback system. Not a normal action.

Thrombus

• Abnormal formation of blood clot in a vessel.(deadly)

Embolus

• Blood clot dislodged, or breaks loose and carried away by the blood flow.(deadly)

Hemophilia

When body struggles to form blood clots. A genetic condition.

Human blood type

ABO blood type

Antigens

 RBC surface molecules, found on RBC’s. Present immediately in a new born.

Whatever antigen is in the blood type=..

The blood type

Antibodies

 Carried in the plasma. Formed 2-8 months following birth.

RH antigens

determine if a cell is positive. If present it is positive (85% of the population). If not present it is negative (15% of the population)

A blood type

 Contains antigen A and antibody B. Rh present means positive and Rh antibody means negative

B blood type

Contains antigen B and antibody A. Rh present means positive and Rh antibody means negative

AB blood type

Contains both A and B antigens and none of the antibodies. Rh present means positive and Rh antibody means negative

O blood type

Contains no A and B antigens but has both of the antibodies. Rh present means positive and Rh antibody means negative. 

Like attacks like means..

Same antibody will attack same antigen. They will never be together.

To form blood types, you need..

all three parts (A, B, and RH) need to be accounted for for every blood type. 

Agglutination

Clumping of the red blood cells when testing for compatibility. Due to reaction between antigens and antibodies. They are not compatible and the clumping leads to clogged blood vessels which leads to kidney failure and death.

How do blood transfusions works

One can only receive blood from blood types that match theirs. Cannot contain antibodies that will react with antigens. The plasma is removed and that contains the antibodies.

A+ can receive blood from

•  Can receive from A+, A-, O+, and O-.

A- can receive blood from

Can receive from A- and O-.

B+ can receive blood from

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

B- can receive blood from

• Can receive from B- and O-.

AB+ can receive from

Any blood type. UNIVERSAL ACCEPTOR

AB- can receive from

• Can receive from all negative types (AB-, A-, B-, and O-).

O+ can receive from

• Can receive from O+ and O-.

O- can receive from

 Can only receive from O-. UNIVERSAL DONOR

How donating blood works

When donating blood, you are donating your RBC, not your plasma. The antibodies from the donor are removed.

Whatever antibody you have in your blood type determines..

which blood you cannot receive.

Positive types can receive

positive and negative types

Negative types can receive

Only negative types

How does Rh pregnancy work?

-HAS to be with a Rh- male and a Rh+ female.

-Their children will be Rh+

What are the risk of Rh pregnancy?

-The child is Rh+ and the mother s Rh- which means their blood can never come in contact during birth

- After first child, Mothers body will create antibodies to attack future Rh+ offspring

-This impact every offspring after first child

Erythroblastosis fetalis

Happens during Rh pregnancy and the fetus could develop a condition and could cause brain damage, possibly death.

RhoGAM shot

Prevents the mother from making the antibodies that will attack future fetuses. Given at 28 weeks and childbirth to the mother.