Bios 355 Exam 3 Flashcards
Systole
Contraction phase
Diastole
Relaxation phase
Cardiac cycle
- Both atria and ventricles are relaxed
- Blood return from venous system enters atria (AV valves between atria & ventricle are open, blood enters ventricle)
- Ventricles expand to accommodate the increase in volume of blood
- SA node initiates AP
- Blood is forced through the AV valves into the ventricles
- AP has progressed through the AV node down the Bundle of his and into Purkinje fibers
- Begin ventricular contraction
- Pressure continues to rise (isovolumetric contraction)
- Ventricular pressure exceeds arterial pressure
- AP is completed
- When ventricular pressure falls below arterial pressure semilunar valves close (2nd heart sound)
- Ventricle replaces isovolumetrically
- When the ventricle pressure falls below the atrial pressure the AV valves will open
Collagen cords (cardiac tendinae)
Tether the valves
End diastolic volume
Max volume in ventricles
Vasculature (flow of blood through the system)
- Blood returns to heart via vena cava
- Through the tricuspid valve to the right ventricle
- Ventricle contracts and pushes blood
- Out of pulmonary circulation
- Coalesce into pulmonary vein
- Pulmonary vein delivery blood to left atria
- Heart contracts
- Aorta > systemic calculation, blood is subdivided to various organs/tissues
- Coalesce into systemic veins
Lungs
Total volume: 5 L/min
% C.O.: 100%
Increase in physical activity: 16 L/min
Brain
Total volume: 0.7 L/min
Weighted volume: 55mL/100g
% C.O.: 14%
Increase in physical activity: 0.7 L/min (no change)
Heart
Total volume: 0.2 L/min
Weighted volume: 70mL/100g
% C.O.: 4%
Increase in physical activity: 0.6L/min
GI tract
Total volume: 1.35L/min
Weighted volume: 100mL/100g
% C.O.: 27%
Increase in physical activity: 0.5L/min
Kidneys
Total volume: 1L/min
Weighed volume: 40mL/100g
% C.O.: 20%
Increase in physical activity: 0.4L/min
Skeletal muscle
Total volume: 1L/min
Weighed volume: 5mL/100g
% C.O.: 21%
Increase in physical activity: 12L/min
Skin
Total volume: 0.25L/min
Weighed volume: 10mL/100g
% C.O.: 5%
Increase in physical activity: 1.5L/min
Characteristics of fluid flow
- Pressure falls as a function of distance (pressure drops due to friction)
- Decrease size of container and the amount of fluid stays the same (pressure increases)
- Blood flows from regions of high to lower pressure
- Resistance opposes flow
Parameters that influence resistance
- Length of the tube (increase length > increase resistance)
- Radius of the tube (decrease radius > increase resistance)
- Viscosity of the fluid (increase viscosity > increase resistance)
Blood vessels
Lined with endothelial cells
Communicate with SM
Low resistance
Arteries
Diameter of 4mm Thick walls 1mm Lots of SM Elastic tissue Fibrous tissue (prevents rupture, strength)
Arterioles
Diameter of 30 micrometers
Walls: 6 micrometers
SM
Little elastic/fibrous tissue
Capillaries
Diameter: 8-9 micrometers
Single layer of endothelial cells
Venules
Diameter: 20-25 micrometers Fibrous tissue Veins Wall: 0.5 mm SM, fibrous and elastic tissue
Blood distribution 1. Pulmonary circulation 2. Heart 3 systemic arteries 4. Systemic capillaries 5. Systemic veins
- 9%
- 7%
- 13%
- 7%
- 64%
Mean pressure
Arteries: 90 mmHg Arterioles: 60 mmHg Capillaries: 25 mmHg Venules: 15 mmHg Veins: 0-10 mmHg
Flow velocity Arteries Arterioles Capillaries Venules Veins
48 cm/s 15 cm/s 1 cm/s 4 cm/s 30 cm/s
Vascular peripheral resistance
Overall resistance to blood flow through the system
Vasoconstriction
Decrease radius Increase resistance Decrease flow 1. NE 2. Serotonin release 3. Endothelin (paracrine)
Vasodilation
Increase radius Decreases resistance Increase flow 1. Epi 2. Nitric oxide 3. Adenosine
Metabolic rate (indicators of high metabolism)
High CO2 Low O2 Low pH High potassium (Increase radius, decrease resistance, increase flow)
Histamine
Local inflammatory molecule
Can cause vascular endothelial cells to contract
Increase in blood flow
Vasodilation
Vasoactive intestinal peptide
Increase blood during digestion
Produce neurons of the enteric nervous system
Capillary exchange
- Single endothelial layer
- Gap between cells that allow fluid out
- Fluid is pushed out of the capillary by the hydrostatic pressure
Fluid bathes cells
Diffusion and transcytosis
Bulk flow
Vascular SM
Regulating the radius of arterioles
Controls blood flow to the capillaries
With histamine
Bigger gaps between endothelial cells Decrease resistance to flow More fluid exits along with proteins Allows WBC to exit Swelling Swelling creates gaps (make it easier for immune cells to get to site of inflammation) Swelling is beneficial at a local level
Cardiac shock
Heart failure
Hypovolumic shock
Blood volume is too low
Blood loss due to hemorrhaging
Septic shock
Bacterial infection
System wide inflammation
Anaphylactic shock
Immune cell over reaction
Miscellaneous agents that influence blood flow
- Inflammation (immune response)
- Malnutrition
- Anemia (low RBC concentration)
Systemic circulation
Left side of heart contracts, pulls blood to periphery
Vasodilate when O2 is low, CO2 is high, pH is low
Pulmonary circulation
Right side of heart contracts, pulls blood to lungs
Vasodilate (SM)
Bloods gains O2
Gets rid of CO2
Angeiogenesis
Growth of blood vessels
Vascularization of a tissue
Exercise promotes angiogenesis in skeletal muscle
Very active during growth and development
Wound healing
Pathologies
Like to promote angiogenesis in coronary heart tissue
Like to prevent angiogenesis in cancer
Blood
5 liters in body
40% blood cells
60% fluid
Erythrocytes
RBC
Gas transport
Leukocytes
WBC
Defense
Immune response
Platelets
Coagulation
Cell fragments
Contain mitochondria, ER, secretory vesicles
Respond to collagen
Proteins in blood
Albumins: transport/attach hydrophobic molecules
Globulins: antibodies
Fibrinogen: blood clotting
Hematocrit
% of RBC in whole blood
Males: 40-52%
Females: 38-48%
Blood cell production
Marrow of bones
RBC > half life of about 4 months
WBC > half life of les than a day (100 billion)
Multipotent progenitor cells
Uncommitted blood stem cell
Lymphocyte stem cell (acquired immune cells, T-cells, B-cells, antibodies)
Uncommitted blood stem cell
Route 1: erythroblast > differentiate > mature RBC
Route 2: megakaryocyte > produce platelets
Route 3: inmate immune cells
RBC production
- Production is regulated by the hormone erythropoietin (EPO)
- EPO is produced by kidney
- EPO target bone marrow (activate the uncommitted blood stem cells)
- Produce erythroblasts (nucleated)
- Nucleus condenses
- Erythroblasts > reticulocyte
- Reticulocytes exit bone marrow (enter circulation)
- 24 hours to mature into adult RBC
(Last about 120 days) - Take on biconcave disk appearance
Reticulocytes
Immature
Migratory
Leave bone marrow and enter circulation
Biconcave disk
Flexible
Increases surface area (more surface area, greater diffusion rate)
Stackable (less adhesion)
Iron transport systems
Intestine
Fe binds to a protein called transferrin
Transferrin: deliver to bone marrow used in Hb synthesis
Thrombopoietin
In liver
Megakaryocytes produce more platelets
Colony-stimulating factor/interleukins
Increase WBC production
Hematopoiesis
Blood cell production
RBC degradation
Damaged RBC are consumed by macrophages Occurs in spleen/liver Digest RBC Bilirubin in the blood Filtered by kidney > excreted in urine
Bilirubin
Incorporated into bile in liver
Excreted
Color feces
Jaundice
Decrease in bilirubin excretion
Increase in bilirubin in blood
Anemia
RBC disorder 1. Blood loss 2. Hemolytic anemia > cytoskeletal defects > hemoglobin defects (sickle cell) > parasitic infection > autoimmune disease > drugs 3. Decrease RBC production > iron deficiency > vitamin deficiency (folic acid, B-12) > certain drugs 4. Kidney problems > decrease EPO production > decrease RBC
Polycythemia Vera
Overproduction of RBC Stem cell dysfunction Hematocrit 60-70% > increase blood velocity > increase flow resistance > decrease O2 delivery > increase pressure (strain on heart)
Secretory vesicles
Contain cytokines (growth-factors)
> stimulate growth to seal the ruptured area
Contain ATP (released into interstitial fluid)
> vasoconstrictor
> decrease blood flow
Serotonin
> vasoconstrictor