Blood Physiology Flashcards
Functions of blood
- transport of substances in blood
- regulation of ion and pH balance
- defense and immune protection
- hemostasis or prevention of blood loss
Blood centrifugation
upper layer: plasma 55%
middle layer: buffy coat - white blood cells and platelets <1%
bottom layer: red blood cells 42% females, 47% males
Composition of plasma
- water, electrolytes, organic molecules, trace elements, gases
Functions of plasma proteins
Albumins: colloid osmotic pressure of plasma, transport substances in plasma
Globulins: clotting factors, enzymes, antibodies
Fibrinogen: forms fibrinogen threads to blood clotting
Transferrin: transport of iron
Made in liver
3 types of blood cells
Red blood cells (erythrocytes): transport of oxygen and carbon dioxide
White blood cells (leukocytes):
Platelets (thrombocytes):
Different types of white blood cells
Neutrophils, eosinophils, basophils, monocytes, lymphocytes
neutrophils
phagocytes
Eosinophils
defense against parasites
Basophils
inflammation
Monocytes
phagocytes and immune defense, leave blood stream and transformed into macrophages
Lymphocytes
B-cell: antibody production and humoral immunity
T-cell: cellular immunity
Hematopoiesis
formation of blood cells
before birth - yolk sac, liver, spleen
after birth - bone marrow
all originate from a pluripotent hematopoietic stem cell
Cytokines
protein that regulates hematopoiesis
released into blood and act on receptors of cells
erythropoietin - production of RBC
thrombopoietin - production of platelets
Structure of hemoglobin
single hemoglobin molecule has 4 globin protein chains (2 alpha and 2 beta chains), 4 heme groups, 4 iron atoms (each hemoglobin can find 4 oxygen)
Manner of oxygen binding
relaxed manner means successive oxygen facilitates finding of next oxygen
oxyhemoglobin is hemoglobin bound to oxygen
deoxyhemoglobin has tight binding structure and has given up oxygen
CO inhalation
Hb has higher affinity for carbon monoxide so it binds very tightly and cannot bind oxygen and deliver it to body
3 factors needed for RBC production
Cytokines: erythropoietin (EPO) stimulates RBC production
Dietary factors: iron needed in Hb, folic acid, vitamin B2
Intrinsic factors: made by cells in stomach to absorb vit B12
EPO RBC production
stimulus for EPO secretion comes from low oxygen in kidneys
EPO acts on bone marrow to turn stem cells to RBC
Increases oxygen carrying capacity of blood
Hypoxia
low oxygen concentration in blood
Transferrin
iron transport protein in blood
Ferritin
protein that stores iron in liver
Recycling hemoglobin
Heme - iron (absorbed in blood or ferritin), biliverdin (bilirubin secreted into bile and enters small intestine)
Globin: broken down into amino acids
Pernicious anemia
lack of intrinsic factor or vit B12
Aplastic anemia
damage of bone marrow due to radiation/drugs
Kidney disease
reduced level of EPO
Hemolytic anemia
increased breakdown due to abnormal shape of RBC
Hemorrhagic anemia
blood loss due to injury, ulcers, chronic menstruation
Sick cell disease
abnormal Hb called HbS, nonflexible membrane and sickle shaped, recessive disease
2 types of immunity
Innate/natural: born with, non-specific defenses, physical or chemical barriers on body, no memory, fast, phagocytes (neutrophils and macrophages)
Acquired/adaptive: acquired over time upon exposure to foreign pathogens (antibodies), has memory, slow, lymphocytes (B and T cells)
Inflammation
innate immune response to tissue injury
cause healing, destruction of non-self, formation of scar tissue (fibrosis)
Histamine
causes vasodilation which increases blood flow causing redness and heat
causes blood vessels to become leaky and permeable allowing protein and fluid to move to extracellular space causing swelling
Cellular events of inflammation
WATCH VIDEO
- WBC move to edge of blood vessels
- WBC attach to endothelial cells and slow rolling along vessel
- WBC activated - expression of proteins on surface of neutrophils and endothelial cells
- Neutrophils bind to complementary proteins on endothelial cells and stop rolling
- WBC squeeze between cells to exit out of blood vessel into tissue spaces
- WBC move to site of inflammation by chemotaxis
- Recognition of foreign agents
- Phagocytosis of foreign agents
Chemotaxis
WBC move against concentration gradient in response to their attraction to chemical factors