Blood and Immunity

Question 1

Functions of Blood

Answer 1

• Transport gases, nutrients, hormones, and metabolic wastes
• Regulates composition of interstitial fluid
• Restricts fluid loss at injury sites via blood clotting
• Defends against toxins and pathogens
• Regulates bod temperature by absorbing and redistributing heat

Question 2

Blood amounts in males and females

Answer 2

5L in 70 kg male

4L in 58 kg female

Question 3

Hematocrit

Answer 3

% of total blood volume occupied by packed RBCs (37-54% is normal)

Question 4

Composition of Plasma

Answer 4

• 92% water
• ions
• trace elements
• CO2, O2
• AA, glucose, lipids, nitrogenous waste
• Albumins (60%)l, Globulins (35%), Fibrinogen (4%)

Question 5

Function of albumin

Answer 5

Colloid osmotic pressure- allows fluid to be drawn back into tissue

Question 6

Function of Globulins

Answer 6

• alpha, beta, gamma

- clotting factors, enzymes, carriers, antibodies

Question 7

Function of fibrinogen

Answer 7

Cleaved to form fibrin in blood clotting

Question 8

Hemoglobin

Answer 8

• 2 alpha chains, 2 beta chains
• 4 heme groups : 1 hemoglobin
• 4 O2 : 1 heme : 1 Fe

Question 9

Erythropoiesis

Answer 9

Synthesis of erythrocytes (RBCs)

Question 10

Erythropoietin

Answer 10

• Promotes erythropoiesis
• synthesized in the kidney
• produced in response to low O2 levels which stabilize TF (H1F1 alpha), activating transcription of erythropoietin gene
• requires iron, vitamin B12, and folate

Question 11

Hematopoiesis

Answer 11

Synthesis of ALL blood cells

- bone marrow has 25% developing erythrocytes, 75% developing leukocytes

Question 12

Cytokines

Answer 12

• regulators of hematopoiesis
• colony stimulating factors
• interleukins (WBCs)
• effects are: survival, proliferations, and differentiation of different cell types

Question 13

Sites of Hematopoiesis

Answer 13

In embryo: yolk sac, liver, spleen, bone marrow
After birth: bone marrow
Adults: pelvis, spine, ribs, cranium, proximal end long bones

Question 14

Jaundice (hyperbilirubinemia)

Answer 14

• high turnover of RBC
• liver disease
• bile duct obstruction

Question 15

Causes of Jaundice

Answer 15

• destruction of stem cells via drugs and radiation (aplastic)
• inadequate nutrients: iron, folic acid, Vitamin b12 (nutritional, pernicious)
• low erythropoietin (renal)
• genetic defects in RBC proteins (i.e. sickle cell beta genes cause fate RBC destruction)
• parasitic infections (e.g. malaria)
• autoimmune reactions
• hemorrhage triggers negative feedback, lower O2, higher erythropoietin

Question 16

Polycythemia

Answer 16

• hematocrit too high (>54%)

- high blood viscosity (harder to pump, leads to clots)

Question 17

Causes of Polycythemia

Answer 17

• primary: abnormal erythrocyte precursors

- secondary: low oxygen delivery to tissues

Question 18

Overall functions of the immune system

Answer 18

• destroys pathogens
• detects and kills abnormal cells
• remove cell debris from body

Question 19

Two defences against pathogens

Answer 19

Innate immunity

• rapid, non-specific
• will go after anything attacking the body

Acquired immunity

• slower, specific
• longer due to need to develop the cells to recognize the pathogen

Question 20

Functions of lymph

Answer 20

• return excess tissue fluid to the blood
• transport pathogens/dendritic cells to lymph nodes
• transport fat from digestive system to the blood (absorbed by lacteals in intestinal villi)

Question 21

Physical barriers

Answer 21

first line of defence

• prevent antigens from entering
• skin
• mucous
• glandular secretions

Question 22

Phagocytosis Routes

Answer 22

1. Toll-like receptors recognize bacterial/viral sequences then bind to pathogen
2. Antibodies bind to antigen at the Fac region, then bind to Fc receptors on phagocyte.

Question 23

Opsonization

Answer 23

coating substance with an opsonin

- ex. antibody