Phys Test 4

Centrifuged blood samples have an added

anticoagulant

what does anticoagulant prevent

prevents clotting EDTA or heparin is added

Centrifuge blood sample volumes

• Plasma 55%

• Erythrocytes 45%

• Buffy coat 1%

Hematocrit (packed cell volume)

percentage of the sample drawn varies with age, gender, health status

Newborn infant hematocrit levels are

55%

Normal hematocrit level

45%

Anemia hematocrit level

30%

Dehydration hematocrit level

70%

Erythrocytes are

red blood cells

Rouleau formation

“stack of coins”

Plasma is ___ of the ECF

25%

Plasma Composition

• water 92%

• plasma 7%

• other solutes 1%

Plasma Protein composition

• Albumins 60%

• Globulins 35%

• Fibrinogen 4%

• Regulatory Proteins 1%

Albumins

• 60% of plasma proteins

• Main contributor to oncotic pressure

Function of Albumens

Are transport proteins that non-specifically bind substances such as bile salts and bilirubin

Globulins

Three types: Gamma, alpha, and beta

Gamma Globulins Func

antibodies (immunoglobulins)

Alpha and Beta Globulins Func

transport proteins and blood clotting factors

Fibrinogen func

(Factor I) component of the blood clotting system

Other Solutes that are part of the plasma

electrolytes (Ca, Na, K, HCO3), organic nutrients, organic wastes

Electrolyte func

normal ECF ion composition essential for vital cellular activities

Organic Nutrients func

used for ATP production, growth. and maintenance of cells (fatty acids, glucose, amino acids)

Organic Waste Func

carries to sites of breakdown or excretion (urea, bilirubin)

Components of the Buffy coat

Platelets and WBCs

Platelets are not

cells

WBCs (neutrophils) are

leukocytes and part of the immune system

Platelets func

blood clot formation and tissue repair

Platelets are cell fragments that break off

megakaryocytes

Platelets (thrombocytes) vs RBCs

• much smaller than RBC

• no nucleus

• role in blood clotting

Leukocytes are what kind of cells

immune

Formed elements are made up of

leukocytes, erythrocytes, and platelets

The blood is which tissue type?

Connective tissue

RBCs are continuously made in

bone marrow

RBCs have no

RNA, DNA, ribosomes, mitochondria

Do RBCs have a long or short life span?

short life span, 120 days

Erythropoiesis

production of RBCs

Hematopoiesis

general term for production of blood cells

Blood cells are produced in what type of bone marrow?

red bone marrow

Blood cells arise from

stem cells

Erythropoietin is a

hormone secreted by kidneys to stimulate RBC production

Can the liver and spleen produce RBCs?

yes

Embryonic liver

RBC production during embryonic and early fetal stages

Fetal Spleen

RBC production during later fetal stages

Adult Liver and spleen can produce

blood cells in an emergency

How do blood cells get into blood vessels?

sinusoid capillaries and continuous capillaries

Sinusoid capillaries are

• in bone marrow, liver, spleen

• wall is fenestrated

• basement membrane is discontinuous

Continuous capillaries are the

most common type

Stem cells do NOT

circulate

Stem cells are located in

bone marrow and liver and spleen

Mature cells are in

circulation

Stages of RBC production

pluripotent stem cell → myeloid stem cell → erythroblast → reticulocyte → erythrocyte

Myeloid stem cell is

committed to become an RBC

Erythroblast’s nucleus

is condensed

Reticulocyte’s (in circulation) nucleus has been

extruded

Erythrocyte has no

organelles

How are old RBCs removed

they’re removed by liver and spleen

RBC structure includes

biconcave, no organelles

RBCs are specialized for transporting

O2 and CO2

RBC cytoplasm is filled with

hemoglobin molecules

RBCs can squeeze through

narrow capillaries, the capillary diameter is smaller than RBC diameter

RBC cytoskeleton is specialized for flexibility what is the major protein?

spectrin

Small blood vessels need regular repair

hemostasis

Hemostasis stops

bleeding in small vessels

3 Steps to stop bleeding

1. vascular spasm (smooth muscle)

2. platelet plug formation (collagen)

3. blood coagulation (clotting)

Vascular spasm with injury causes

constriction to diameter, smooth muscle contracts

Platelet plug formation

• Exposed collagen at site of injury

• Positive feedback loop

• vWF

What stops positive feedback loop

ADP signals to endothelium to release inhibitors, ADP and TX A2 aggregate platelet plug

von Willebrand Factor (vWF)

adheres to collagen and platelets, activates the platelets

Blood coagulation in an injury

Fibrinogen is converted to fibrin and involves cross linking. Fibrin is a web that traps blood cells

If blood is drawn and left to stand with no anticoagulant what happens

the ability to cot is intrinsic to the blood

Intrinsic clotting pathway

• Clotting from inside the blood vessel

• 7 steps

• uses factors that circulate in the blood

Extrinsic clotting pathway

• clotting external to the blood vessel

• uses a tissue factor outside the blood

• 4 steps

• bruising

Factor XII is for what pathway

intrinsic clot pathway

Tissue factor (III) is in which pathway

extrinsic clot pathway

Factor X is in what pathway

both extrinsic and intrinsic

Bruising is

hematoma is produced and can be visible under the skin

(extrinsic) Heme breaks down to

biliverdin

(extrinsic) Biliverdin is converted to

bilirubin

Blood clotting “buys time” for repairing the damage

• fibroblasts form new endothelial cells (line blood vessel wall)

• clot is slowly dissolved from within by plasmin, a fibrinolytic enzyme

• plasmin circulates as plasminogen

• macrophages clean up debris

Psuedopods

fine sheets of membrane that the macrophage is extending to engulf the red blood cells in the spleen

Factor XII initiates

clotting and dissolution

Factor XII → plasminogen →

plasmin

Role of the kidneys

• elimination of metabolic waste

• urine production

• fluid and electrolyte balance

• plasma osmolarity regulation (solute conc.)

• acid-base balance

Digestive tract, liver, kidneys, and skin do what?

• recondition the blood

• receive more blood than needed for the organ’s metabolism

Kidney: Filtration

• filter the plasma (water and solutes)

• filtered by capillaries into tubules

Kidney: reabsorption

• reabsorb fluid and electrolytes (conserve fluids and salts)

• take back into the capillaries from tubules

Kidney: Secretion

• secrete into the urine (remove waste and excess salt)

• from capillaries into tubules

Kidney: excretion

excrete urine (ultimately eliminate waste to external environment)

The nephron includes

the glomerulus, arterioles, and tubules

Fluid flow through the nephron

1. glomerulus and Bowmans capsule

2. proximal convoluted tubule

3. loop of Henle, thin descending limb

4. loop on Henle, thick ascending limb

5. distal convoluted tubule

6. distal tubule (straight portion)

7. collecting duct

Peritubular capillaries

• reabsorption

• gas exchange

Vasa Recta

• reabsorption

• gas exchange

The glomerulus is a ball of…

capillaries that has arterial blood only

Does the afferent arteriole have a wide or narrow diameter?

wide diameter

Does the efferent arteriole have a wide or narrow diameter?

narrow diameter

The glomerulus is surrounded by

Bowman’s capsule

Bowman’s capsule has 2 layers, what are they?

outer layer and inner layer

Plasma is filtered into

Bowman’s capsule

Plasma is filtered through

filtration slits

Glomerular capillaries are

fenestrated capillaries