6.5 Blood

Question 1

What are the components of blood?

Answer 1

Plasma

Formed elements: RBC, WBC, platelets

Question 2

What is plasma composed of?

Answer 2

90% water
6-8% protein: albumin, globulins, fibrinogen
1% electrolytes: Na+, Cl-, HCO3-, K+, Ca2+
nutrients: glucose, amino acids, vitamins, lipids
waste: urea, creatinine, bilirubin
dissolved gases: O2, CO2
hormones: steroid and thyroid hormones carried by plasma proteins

Question 3

How does plasma act as a buffer?

Answer 3

because plasma is 90% water, it acts as a pH buffer, resisting changes in pH

Question 4

How does plasma maintain osmotic balance?

Answer 4

ater, electrolyte, protein content balanced to maintain osmotic gradients

Question 5

What are the plasma proteins? Which is most common?

Answer 5

Albumin protein:
carrier
maintains osmotic balance between blood and ECF
Globulin proteins:
carriers
form antibodies (made by WBC’s)
Fibrinogen:
blood clotting

Question 6

What is the structure of an RBC?

Answer 6

biconcave, “donut” shape
flattened
small size (7.5 μm diameter)
no nucleus, few organelles (no mitochondria)
structural proteins
97% hemoglobin protein

Question 7

What makes hemoglobin?

Answer 7

4 subunits:
2 A, 2 B
4 Fe molecules

Question 8

How many oxygen molecules can each HgB carry?

Answer 8

4

Question 9

Where are old RBCs degraded? How?

Answer 9

By macrophages in spleen, liver, red marrow

Question 10

What happens to heme, iron, and the globin in HgB?

Answer 10

Heme–> bilirubin, sent to liver to be excreted as bile
Iron- taken up by macrophages for reuse
Globin- broken to AAs and recycled

Question 11

What causes jaundice?

Answer 11

Bilirubin build up

Question 12

What causes Hyperbilirubinemia?

Answer 12

Increased breakdown of RBCs

Decreased elimination of bilirubin by liver

Question 13

What is hematopoiesis?

Answer 13

blood cell formation from stem cells in the red bone marrow

Question 14

Where does erythropoiesis occur? What hormone stimulates it? Describe the process

Answer 14

occurs in Red Bone Marrow: sternum, ribs, pelvis, long bones
requires hormone: erythropoieitin (EPO)
stimulus: low O2
kidneys release EPO
effector: red bone marrow
response: increased erythropoiesis, make more RBC’s
Stem cells make more stem cells which make RBCs, WBCs, platelets
Reticulocyte- precursor cell to RBCs, can measure reticulocyte to see if problem with maturation of RBCs

Question 15

What are the stimulus, receptor, control center, effector and response of erythropoiesis regulation?

Answer 15

stimulus: low O2 in blood
receptor: kidney cells, increased hypoxia inducing factor (HIF)
control center: kidneys increase erythropoietin (EPO)
effector: red bone marrow
response: make more RBC’s

Question 16

Why are B12 and folate important for RBC production?

Answer 16

necessary for DNA synthesis and stem cell division
** including Hematopoeitic stem cells
Very sensitive, even slight changes in B12 and Folic acid levels affect production
Some anemias are from low B12 levels

Question 17

Where is iron absorbed, carried, and stored?

Answer 17

Absorbed by small intestine
recycled after RBC breakdown
carried through bloodstream to bone marrow by transferrin protein
carried to the liver for storage as ferritin

Question 18

What is anemia? What are common causes

Answer 18

Anemia occurs when blood oxygen carrying capacity is too low
Many causes:
Blood Loss
trauma
bleeding
Low RBC production
iron deficiency
B12 deficiency
EPO deficiency
red bone marrow damage
High RBC breakdown
genetic diseases (sickle cell anemia, thalassemia’s)

Question 19

What are the 5 types of WBCs?

Answer 19

Neutrophils
Lymphocytes(B-lymphocytes, T-lymphocytes)
Monocytes
Eosinophils
Basophils

Question 20

What are the function of neutrophils? Prevalence

Answer 20

(50-70%): phagocytes, first response to infection, stress, inflammation
engulf and destroy bacteria using lysosomal enzymes in granules
release free radicals

Question 21

What is the function of lymphocytes? Prevalence?

Answer 21

25%) form adaptive immunity
B-cells: produce antibodies against foreign cells or viruses
T-cells: kill infected cells, cancerous cells

Question 22

What is the function of monocytes?

Answer 22

Become macrophages
phagocytes, inflammation, antigen response
engulf and destroy pathogens, debris

Question 23

What is the function of eosinophils? Prevalence?

Answer 23

(2-4%): allergic reaction and parasite defense

release chemical mediators and enzymes: histamine, nucleases, lipase, plasminogen in granules

Question 24

What is the function of basophils, prevalence?

Answer 24

(0.5 -1%): inflammation, allergy and parasite defense

histamine, prostaglandins, leukotrienes, heparin in granules