Physiology Of Blood Flashcards
Chemoreceptors for blood locations
Peripheral chemoreceptors usually found in carotid bodies near the bifurcation of the common carotid arteries
Chemoreceptors for blood reasons for response
Respond to the follow
- reduced arterial Po2
- Acidemia
- hypoperfusion
- hyperthermia
Most functions of chemoreceptors are to decrease excess H+ ions and increase Po2.
- usually does not affect Pco2*
- this is done through changes in respiratory rates
Carotid body nerve impulses increase at a rate inverses to the arterial partial pressure of oxygen
- lower PO2 = high nerve impulses
Hypoxia inducible factor (HIF)
In normal levels of oxygen, this factor is degraded with the interactions of Von Hippel-Lindau protein (VHL)
- must bind HIF-a with oxygen in cells to bind VHL
In hypoxia, VHL is not present due to inability of HIF-a to bind with oxygen. This results in HIF-B factor and HRE being produced which transcribes genes to promote erythropoiesis and angiogenesis
- combats hypoxia
Transcription factors = HIF-1a and ARNT
Hypoxia inducible factor broad mechanisms
Have 3 subunits: 2a, 2b, 3a
2a and 2b function to promote angiogenesis and erythropoiesis
3a is unknown officially but is believed to suppress HIF gene expression in Von hipped Linda’s disease
Erythropoietin
Glycoprotein growth factor that is synthesized in the kidneys and serve as the major stimulus to erythropoiesis in red bone marrow
- stimulates proerythroblasts to differentiate into erythrocytes
Transport of CO2 in the blood
90% in the globin chains of the hemoglobin
10% in the plasma
Can be in 3 forms
- dissolved CO2 in plasma
- CO2 bound to albumin or globin chains in hemoglobin
- chemically modified CO2 usually in the form of bicarbonate (HCO3) MOST COMMON
- 70% of the plasma transferred in the blood is in the form of bicarbonate*
- either bound to hemoglobin or in the plasma
Types of nutritional anemia and the underlying dysfunctions associated
usually based of MCV
Microcytic: MCV < 80
- deficiencies in iron, ascorbate (Vit. C) and/or pyridoxine
Normocytic: MCV = 80-100
- protein malnutrition
Macrocytic: MCV > 100
- deficiencies in folate of Vit B12
Normal hematocrit levels, hypoxia hematocrit levels and polycythemia hematocrit levels
Normal = 37-48%
Anemia = 30%
Polycythemia = 70%
All approximate levels
Factors that increase lymph flow
Increases in all of the following:
Capillary hydrostatic pressure Capillary surface area Capillary permeability Tissue metabolism Muscle activity
Factors that promote edema formation
Decreased plasma protein concentration
Arteriolar dilation
Venous/lymphatic obstruction
Release/presence of histamine
Increases in the following
- capillary hydrostatic pressure, surface area and permeability
- tissue metabolism
Lymphatic filariasis
Disease caused by 3 possible species of nematodes and is spread by mosquitoes. One of the leading causes of global disability
Causes edema in adults by blockage of adult worms in lymph nodes
Possible agents:
- bancrofti
- Malayi
- timori
Kwashiorkor
A disorder in which edema occurs due to extreme wasting of the underlying tissues and very low serum albumin levels
- edema occurs via reduced plasma on optic pressure
Symptoms:
- fatty liver
- decreased serum albumin, hypoglycemia, hypophosphatemia
- weight gain
- depigmentation of skin
- course, red/gray hair in children
- presents with anemia usually
What is the physiological buffer to acidemia?
Bicarbonate ions
- increase in bicarbonate ions or decreases inCO2 increase the pH of blood
Serum vs plasma
Plasma = has clotting factors
Serum = does not have clotting factors
Functions of blood
Transport
Regulate O and ion concentrations
Restrict fluid losses
Defend against toxins and pathogens
Stabilize body temp
Plasma proteins
Albumins
Globulins
Fibrinogen
Regulatory proteins
constitutes 7% of plasma
Solutes in plasma
Electrolytes
Organic nutrients
Organic wastes
Most common white blood cells to least common
Neutrophils (40-80%)
Lymphocytes (20-40%)
Monocytes (2-8%)
Eosinophils (1-4%)
Basophils (<1%)
Oxygen pressure locations highest to lowest
Lung capillaries (100%)
Arterial blood (90%)
Capillaries (85-45%)
Venous blood (40%)
Steps of EPO in hypoxia
HIF-a stimulates renal fibroblasts to up-regulate EPO gene transcription
EPO is synthesized and then secreted into blood to get to the bones
EPO then promotes differentiation of proerythroblasts into RBCs
High altitude vs low altitude people venous and arterial values
High elevations:
- arterial blood has higher percentage of oxygen in blood at about 15mmHg lower overall pressure of oxygen in blood
- venous blood has a slightly higher oxygen percentage in blood at roughly 20mmHG lower overall pressure of oxygen in blood
due to higher overall levels of RBCs in high altitude populations and the RBCs are more efficient at delivering it to tissues
How are blood glucose levels controlled?
Suppression of hepatic glucose production
Stimulation of hepatic glucose uptake
Stimulation of peripheral tissue glucose uptake
What type of immune cell is produced by both monocytic and lymphocytic lineages
Dendritic cells
What is the most common antibody in the serum?
IgG = from womb until 3 yrs
IgM = 3 yrs - death
Extrinsic vs intrinsic systems
Extrinisc: begins via tissue factors with factor 7 as the precursor to the cascade
Intrinsic : begins with surface factors interacting with factor 12.
- precursor is factor 9
- vitamin K is required for both pathways*
- both pathways lead to production of cross-linked fibrin clot*
Heparin vs warfarin
Heparin: blocks factor 10 (low dose) and blocks thrombin (high does)
Warfarin: blocks all vitamin K dependent factors from being produced ( 7, 9,10, prothrombin)
both stop coagulation
Production of thrombin from prothrombin
Requires factor 5, lipids and calcium to form thrombin
- thrombin is the main factor for cleaving fibrin from fibrinogen
What two molecules are secreted from vessel injury to promote platelet factor 3
ADP and TXA2
- platelet factor speeds up prothrombin -> thrombin conversion
Coumadin targets
Thrombin and factor 8
- prevents fibrinogen -> fibrin conversion
Layers of centrifuged blood
Plasma
Buffy coat
RBCs
in this order
Reynolds number
Density x diameter x velocity/ viscosity
- determines rate through a pipe (vessel) based on these 4 factors*
- viscosity l is inversely related to Reynolds number*
- narrowing of a blood vessel increase Reynolds number since the velocity increases*
Types of blood flow
Streamline/laminar flow: normal pattern of flow that is highly efficient and follows poisuellie law
- is silent on examination
- raynauds number of 1-2000
- low driving number
Turbulent flow: higher than average velocity that is often caused by narrowing of vessels.
- does not follow poisuellie law and is inefficient with energy
- generates a Bruit or murmur upon examination
- raynauds number is greater than 2000
- high driving pressure
