ch 18- blood

functions of blood

moves, gases, nutrients, wastes +hormones

through cardiovascular system

• heart pumps blood

arteries

transport blood away from heart

veins

transports blood toward heart

capillaries

allow exchange btw floor + body tissues

Erythrocytes: formed element

red blood cell

transport respiratory gases

leukocytes: formed elements

white blood cells

defend against pathogens

platelets

help form clots to prevent blood loss

plasma

fluid portion of blood

contains protein + dissolved solutes

transportation of blood

carries oxygen from and carbon dioxide to the lungs

transports nutrients, hormones, heat + waste products

protection of blood

leukocytes, plasma proteins + other “rules” protect against pathogens

platelets +certain plasma proteins against blood loss

body temperature

blood absorbs heat from body cell

heat released at skin blood vessels

body pH

blood absorbs acid + base from body cells

blood contains chemical buffers

fluid balance

water is added to blood from GI tract

water lost through urine, skin, respiration

fluid is exchanged btw blood + interstitial fluid

• blood contains proteins + ions help maintain osmotic balance

oxygen rich blood is

bright red

oxygen poor blood is

dark red

how many liters of blood in a adult

volume= 5 liters

5 is a magical number

viscosity

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

viscosity increases if

erythrocytes # increase

viscosity increases if

fluid decreases

plasma concentration

its of solutes ex: proteins + ions

determines direction of osmosis across capillary walls

• ex: dehydration plasma hypertonic: fluid drawn from tissues

temperature

blood is 1 degree c higher than measured body temp

blood pH

slightly alkaline

crucial for normal plasma protein shape (avoiding denaturation)

what is blood’s pH

7.35-7.45

whole blood

plasma + formed elements separated into parts by centrifuges

Centrifuged: erythrocytes

bottom, red layer

about 44%

Centrifuged: Buffy coat

very thin (1%) middle layer

composed of leukocytes + platelets

Centrifuged: plasma

straw-colored liquid at top of tube

about 55%

Hematocrit

% of volume of all formed elements

males: 42- 56%

females: 38-46%

HEMATOCRIT clinical defintion:

% of only erythrocytes

why do men have more blood?

testosterone causes more erythropoietin secretion by kidneys

Composition of blood plasma

water- 92%

proteins- 7%

dissolved molecules + ions- 1%

in extracellular fluid

higher protein concentration

is blood a colloid?

YES

has dispersed proteins

most produced in live

• extras in leukocytes etc.

Colloid osmostic pressur (COP)

prevents loss of fluid from blood as it moves through capillaries

• maintains blood volume + pressure

• decreases w diseases→ fluid loss + tissue swelling

  • liver disease dec. prod. of plasma proteins

  • kidney disease inc. elimination of plasma proteins

albumins

smallest + most ABUNDANT- 58%

exert greatest COP

act as transport proteins for lipids, hormones + ions

globulins

2nd largest- 37%

smaller alpha globulins and beta

• transport some water-insoluble “cures”, hormones, metals, ions

Gamma-globulins (immunoglobulins or antibodies)

part of body’s defenses

fibrinogen

makes up 4% of plasma proteins

contributes to blood clot formation

what happens to fibrinogen when damaged?

converts to insoluble fibrin strands

serum

plasma w clotting proteins removed

regulatory proteins

<1 % of total proteins

• enzymes + hormones

is blood also considered a solution?

YES

contains dissolved organic + inorganic ‘cures” + ions

electrolytes, nutrients, gases, waste products

polar or charged dissolve easily

NP require carrier proteins

hematopoiesis

production of formed elements

• in red bone marrow of certain bones

Hemocytoblasts

stem cells

pluripotent: differentiate into many types of cells

myeloid line

forms erythrocytes, all leukocytes

(NOT lymphocytes + megakaryocyctes) cells that produce platelets

Lymphoid line

forms only lymphocytes

T- lymphocytes: thymus

B- lymphocyte: bone marrow

NK- natural killers

colony-stimulation factors (CSFs)

stimulate hematopoiesis

Erythropoiesis

red blood cell production

• requires iron, B vitamins, amino acids

Erythropoiesis steps

1. myeloid stem cells: multi CSF

2. forms proerythroblast

3. becomes erythroblast

4. becomes normoblast

5. becomes reticulocyte

6. becomes erythrocyte

myeloid stem cell

responds to multi-CSF

proerythroblast

large nucleated cell

erythroblast

smaller, produces hemoglobin

normoblast

smaller, more hemoglobin enucleate

reticulocyte

lacks organelles except ribosomes that make hemoglobin

erythrocyte

ribosomes have degenerated

leukopoiesis

production of leukocytes (WBC)

involved maturation of granulocytes, monocytes, lymphocytes

which are Granulocytes?

neutrophils, basophils, eosinophils BEN

what is the process of making granulocyte ?

multi- CSF and Gm-CSF cause myeloid stem cell to form progenitor cell

progenitor cell becomes myeloblast that becomes a granulocyte

multi- CSF+ GM-CSF→ myeloid stem cell → progenitor cell→ myeloblast→ granulocyte

Monocytes

also from myeloid stem cells

stem cells→ progenitor cell

M-CSF prompts progenitor cell to become mono blast

monoblast → promonocyte→ monocyte

myeloid stem cell→ progenitor cell→ M-CSF → mono blast→ promonocyte → monocyte

lymphocytes

from lymphoid stem cells

stem cells → B-lymphoblasts + T- lymphoblasts

lymphoblasts mature→ B + T- lymphocytes

some become NK (natural killer) cells

thrombopoiesis

platelet production

megakaryoblst from myeloid stem cell

megakaryoblast come from thrombopoietin

thrombopoietin

hormone that plays a role in platelet production

megakaryocte

large size, multi lobed nucleus in red bone marrow cells that are the sole platelet production from mammals

from thrombopoietin

What do proplatelets do?

made from megakaryocytic

large cell produced pro platelets- long extensions

extend through blood vessel wall into bloodstream

blood flow “ slices” off fragments which are platelets

erythrocytes

RBC

small, flexible formed elements

lack nucleus and cellular organelles; packed with hemoglobin

have biconcave disc structure

• latticework of spectrum protein for support and flexibitliy

• transport oxygen + carbon dioxide btw tissues and lungs

why are erythrocytes flexible?

in order to squeeze btw the very thin walls of capillaries

hemoglobin

red-pigmented protein

transport O2 + CO2

termed oxygenated when loaded with oxygen

deoxygenated (not the best term) when some lost

structure of hemoglobin

2 alpha chain + 2 beta chain= 4 globin

• each chain has a heme group

  • heme: iron center

    • oxygen binds to the iron ion ( like a seat) so hemoglobin can bind 4 oxygen molecules

does oxygen bind to iron

YES

binding is weak

rapid attachment in lungs

rapid detachment in body tissues

does carbon dioxide bind to iron

NO- binds to globin protein (NOT IRON)

binding is weak

attachment in body tissues

detachment in lungs

erythropoietin (EPO)

hormone from KIDNEYS

secretion bc of decrease in blood oxygen

• red marrow responds to EPO making more erythrocytes releasing into circulation

• low oxygen levels at high altitude influence EPO levels

• Testosterone stims. EPO in kidneys

  • why males have more erythrocyte count, more hematocrit

• erythrocytes increase blood oxygen carrying capacity

  • increase blood O2 inhibits EPO release (neg. feed back)

blood doping

blood removal increases EPO production

erythrocytes back in before comp

how long do erythrocytes last?

maximum 120 days

old cytes are phagocytized in spleen or liver

erythrocytes destruction

lack organelles so they can’t synthesize protein for repairs

globins + membrane proteins broken into amino acids

• for protein synthesis

iron from hemoglobin transported by transferrin protein → liver

• bound to storage proteins: ferritin, hemosiderin