Exam 2 Flashcards
What is Atherosclerosis?
Plague build-up in the systemic circuit which lowers blood to cells of the tissues in the extremities
Coronary Artery Disease
Plague build-up in the coronary circuit which lowers oxygen to the cardiac muscle cells
Hemodynamics
The physiology of blood flow
Why is blood flow necessary?
Necessary for the cells to receive nutrients like oxygen and glucose
How do you calculate pressure?
Pressure = Cardiac Output X Resistance
What is the relationship between resistance and cardiac output?
Inversely related, so if R goes up, CO will go down
What is the relationship between cardiac output and pressure?
Directly related, so if CO increases, R will increase
Pressure
Force that is exerted on the inner wall of the vessel; it is the push exerted on the tunica
What happens to pressure when the heart contracts?
Pressure increases
What is resistance?
Opposition to blood flow
What is blood viscosity?
How thick the blood is
What does high viscosity lead to?
High resistance which leads to high pressure
What does low viscosity lead to?
Low resistance which leads to low pressure
What changes blood viscosity?
Red cell mass, red cell deformity, plasma levels, amount of water, number of cells in the blood
What happens to blood viscosity when water levels decrease?
Blood viscosity increases
What happens to resistance as blood vessel radius increases?
As a vessel’s radius increases, resistance decreases
How does the sympathetic system affect vessel diameter?
Causes vasoconstriction; resistance goes up, pressure goes up
How does the parasympathetic system affect vessel diameter?
Causes vasodilation; resistance goes down, pressure down
How does blood vessel length affect resistance?
Greater blood vessel length, greater the resistance
What increases blood vessel length?
Increase in adipose tissue
How does obstruction of blood vessel affect resistance?
Increases resistance
Systolic Pressure
Pressure in the artery when the ventricles are contracting: top number
Diastolic Pressure
Pressure in the artery when the ventricles are relaxing: bottom number
What is mean arterial pressure?
Average pressure in the systemic circuit during a complete cardiac cycle
How do you calculate MAP (mean arterial pressure)?
MAP = diastolic pressure + 1/3 (systolic pressure-diastolic pressure)
What organ systems are involved in short -term regulation of blood pressure?
Autonomic Nervous System and Endocrine System
Short term effects of the Sympathetic Nervous System on blood pressure
Increases Heart Rate, Increases Stroke Volume, and causes vasoconstriction
Short term effects of the Parasympathetic Nervous System on blood pressure
Decreases heart rate, no effect on stroke volume, and causes vasodilation
Short term effects of the NE/E hormones on blood pressure
Increases heart rate, increases stroke volume, and increases resistance
Short term effects of the Thyroid hormones on blood pressure
Causes up-regulation of the receptors for NE/E, so it causes increase of heart rate, increase of stroke volume, and increase of resistance
Short term effects of Angiotensin II hormone on blood pressure
Most powerful vasoconstrictor; causes an increase in resistance
Short term effects of ADH on blood pressure
Increases resistance
Short term effects of ANP on blood pressure
Decreases resistance, causes vasodilation
What organ systems are involved in long-term regulation of blood pressure?
Endocrine and Urinary
Long-term effects of ADH on blood pressure
Increases reabsorption of water in the kidney, increases blood volume
Long-term effects of Angiotensin II and Aldosterone on blood pressure
Increases reabsorption of sodium in the kidney (water follows by osmosis), increases blood volume
Long-term effects of ANP on blood pressure
Causes excretion of sodium into the urine (water follows by osmosis), decreases blood volume
Erythrocyte
Red blood cell
What type of shape is an erythrocyte
Biconcave disc
Why are erythrocytes biconcave?
Gives the erythrocytes a large surface-to-volume ratio, which is critical for gas exchange
What is hemoglobin?
Proteins within erythrocytes that carry oxygen
What is a heme group?
An iron-containing compound that is bound to a polypeptide subunit inside a hemoglobin
Antigen found in Type A Blood
A antigens
Antigen found in Type B Blood
B antigens
Antigen found in Type AB Blood
A and B antigens
Antigen found in Type O Blood
Neither A nor B antigens present
Antibodies found in AB+ Blood
No antibodies found
Antibodies found in AB- Blood
Anti-Rh antibodies only after the blood comes into contact with the Rh antigen
Antibodies found in B- Blood
Anti-A and Anti-Rh antibodies only after the blood encounters the Rh antigen
Antibodies found in O- Blood
Anti-A, Anti-B, and Anti-Rh antibodies only after the blood encounters the Rh antigen
Antibodies found in A+ Blood
Anti-B antibodies
Antibodies found in A- Blood
Anti-B and Anti-Rh antibodies only after the blood encounters the Rh antigen
Antibodies found in B+ Blood
Anti-A antibodies
Antibodies found in O+ Blood
Anti-A and Anti-B antibodies
What happens if a person were to receive a blood type that has antigens that match their antibodies?
The blood would agglutinate
What is hemolysis?
Rupture of erythrocytes
What is hemolytic disease of the newborn?
When an Rh-negative mother carries and gives birth to an Rh-positive fetus. During birth, fetal erythrocytes enter the mother’s blood, which stimulates her immune system to produce anti-Rh antibodies. In subsequent pregnancies, maternal anti-Rh antibodies can cross the placenta into the blood of the fetus, hemolyzing (rupturing) fetal erythrocytes if they are Rh+ and potentially killing the fetus.
What is a transfusion reaction?
Agglutination of the donated erythrocytes due to the blood type not being match which causing the donor erythrocytes to be damaged
What is an universal donor?
An individual with type O- blood who is able to donate blood to any blood type due to the absence of A, B, and Rh antigens on his or her erythrocytes
What is an universal recipient?
A person with type AB+ blood that can receive blood from any blood type due to the absence of anti-a, anti-b, and anti-Rh antibodies
What is hematopoiesis?
Process that produces the formed elements in the blood and occurs in the red bone marrrow
What are hematopoietic stem cells?
Cells located in red bone marrow that can become any type of formed element of the blood
What is erythropoiesis?
Process of differentiation and maturation of erythrocytes
What is Reticulocyte?
An immature erythrocyte released into the circulation that still has a nucleus and some organelles
Describe the regulation of erythropoiesis
Blood oxygen levels decrease below normal range
Kidney cells detect a low oxygen level
Kidneys produce more erythropoietin and release it into the blood
Production of erythrocytes increases
Blood level of oxygen rises to normal
What happens when Erythrocytes die?
Erythrocytes become trapped in the sinusoids of the spleen
Spleen macrophages digest erythrocytes
Hemoglobin is broken down into amino acids, iron ions, and bilirubin
Hemoglobin is broken down into amino acids, iron ions, and bilirubin
Hemoglobin is broken down into amino acids, iron ions, and bilirubin
What is bilirubin?
A yellow-orange pigment that is formed by the liver because of heme breakdown and is excreted in the bile. Causes the yellow pigment of urine and skin during liver failure
What is anemia?
Decreased oxygen-carrying capacity of the blood
Causes of anemia
Decreased Hemoglobin
Decreased hematocrit
Abnormal hemoglobin
What is iron-deficiency anemia?
Anemia caused due to inadequate dietary iron, reduced intestinal absorption of dietary iron, or slow blood loss (including menstruation)
What happens when there are not functional iron-containing heme groups?
Erythroblasts cannot make hemoglobin
What is pernicious anemia?
Anemia as a result to a vitamin B12 deficiency, which is important for red blood cell production
What is hemolytic anemia?
Excessive erythrocyte destruction; most common in chemo patients
What is aplastic anemia?
When the red bone marrow stops producing erythrocytes; caused by certain medications, or exposure to ionizing radiation
What is sickle-cell disease/anemia?
Abnormal hemoglobin that are sickled shape and can get stuck in the capillary beds
What is hydrostatic pressure?
Force that a fluid exerts on the wall of the blood vessels
What is colloid osmotic pressure?
An osmotic pressure gradient created by the plasma proteins; water moves into the plasma from the interstitial fluid due to plasma’s higher colloid osmotic pressure
What is osmotic pressure?
Force that would need to be applied to stop water from moving into the cell by osmosis
Filtration
The movement of a fluid by a force such as hydrostatic pressure
What is net filtration pressure?
Difference between the filtration and reabsorption forces in the capillary
How does filtration occur in the capillaries?
Substances are transferred from the blood inside of the capillary to the interstitial space
How does reabsorption occur in the capillaries?
Movement of substances from the interstitial fluid to the blood in the capillaries
What is HPc?
Push of blood on the capillary wall; occurs inside the capillary; is filtration
What is HPif?
Push of interstitial fluid on the wall of the capillary; occurs outside the capillary; is reabsorption
What is OPc?
Pull on the H2O of large proteins in the blood; occurs outside the capillary; is reabsorption
What is OPif?
Pull on H20 of small solutes in the interstitial fluid; occurs outside the capillary; is reabsoprtion
What two factors cause Edema?
Excessive Filtration
Inadequate Reabsorption
Normal NFPbed
6 mmHg
Normal/ Accepted MAP values
95 mmgHg
What is the difference between elastic and muscular arteries?
Causes of Atherosclerosis
High cholesterol, high blood pressure, smoking, diabetes, obesity, physical activity levels
Treatment of Atherosclerosis
Medications, stents, weight loss, change of diet
As pressure increases, how does blood flow change?
Blood flow will increase
As resistance increases, how does blood flow change
Blood flow will decrease
As cross-sectional area increases, how does velocity of blood flow change
Blood flow will decrease
Where is velocity the slowest in the blood vessels?
The capillaries because it allows more time for diffusion to occur in the capillary bed
How does an increase in Resistance affect BP?
Blood pressure will increase
How does an increase of blood volume affect BP?
Will cause blood pressure to increase
What things affect blood pressure?
Cardiac Output
Blood Volume
Viscosity of Blood
Resistance
How is BP different in the Pulmonary vs. Systemic circuits?
Systemic circuit has a much higher pressure than the pulmonary circuit since it has to travel further distances
How do we calculate pulse pressure?
Systolic- Diastolic
How is venous return to the heart assisted?
Venous Valves
Skeletal muscle pump
Respiratory Pump
Vasoconstriction
What is Hypovolemic Shock?
When there is a decreased amount of blood
What causes Hypovolemic Shock?
Loss of blood or loss of water in the body; normally from trauma
What is Cardiogenic Shock?
When there is decreased cardiac output
What is Anaphylactic/ Septic Shock?
When there is excessive vasodilation
What causes Cardiogenic Shock?
A lack of oxygen to your heart and heart attack
What causes Anaphylactic/ Septic Shock?
Bacterial infections that lead to sepsis, asthma attacks, anaphylactic reactions
Fenestrated Capillary
Capillary with small pores that allow diffusion to take place quickly. Located where substances must rapidly enter or existed the blood
Continuous capillaries
Capillary where the endothelial cells are tightly joined by junctions; least leaky and permit the fewest substance to enter or exit the blood. Example is the blood brain barrier
Sinusoidal Capillaries
Capillary where there are large pores in the endothelial cells; leakiest capillaries; located in organs and tissues like the liver, spleen, and bone marrow; Allow for the transfer of large substances such as blood cells
Microcirculation
Total blood flow that occurs in the capillaries
Thoroughfare Channel
Allows for blood flow straight from the metarteriole to the venule without passing through the true capillaries; sympathetic nervous system uses this for quicker gas exchange
Myogenic Mechanism
Autoregulatory mechanism in the blood vessels by which the degree of stretch of the vessel wall triggers reflexes that maintain blood flow to a tissue
What is tissue perfusion?
Blood flow to a tissue through a capillary bed
What happens to arterioles and tissue perfusion via the myogenic mechanism when blood pressure increases or decreases
When blood pressure increases, stretch activation of smooth muscle causes constriction of the arterioles, which restrains the increased blood pressure to keep tissue perfusion constant
Which chemicals produce changes in tissue perfusion? How do they affect tissue perfusion?
Carbon dioxide and hydrogen ions which cause vasodilation and causes tissue perfusion to increase; oxygen has the opposite affect
How is the pattern of blood flow in the coronary circulation different from that in the rest of the systemic circuit
Coronary blood flow decreases during systole and increases during diastole
What is Hyperemia
Increased blood flow
In which direction does the hydrostatic pressure gradient drive the movement of water in a capillary?
Water is driven out of the capillary and into the interstitial fluid
In which direction does water move when an osmotic gradient is present?
Draws water into the capillary
Where are common pulse points?
Carotid artery, radial artery, brachial artery, femoral artery
Which substances does blood transport through the body?
Gases, solutes, nutrients, hormones, and waste
Symptoms of Anemia;
Pallor, fatigue, weakness, shortness of breath, and elevated reticulocyte
Metabolic Mechanism
When there is an increase in metabolic activity which causes low oxygen and an increase in carbon dioxide. The arterioles vasodilate to feed more blood into the capillary; when CO2 levels are high, this mechanism lowers pH to be more acidic
What is the Skeletal Muscle Pump?
Muscle contraction or relaxation; when the muscle contracts, blood is squeezed upwards toward the heart
What is the Respiratory Muscle Pump?
Movement of the diaphragm during breathing creates blood flow; inhalation increases blood into the thoracic veins
What happens when there is low venous return?
Low venous return causes a decrease in EDV which decreases preload causing SV to decrease CO then pressure decreases
What is a Baroreceptor?
Type of mechanoreceptor that helps to regulate blood pressure by detecting pressure changes in the blood vessels
What is a Stroke?
Damage to the brain caused by a disruption of blood flow
Causes of strokes?
Blockage of the brain’s arteries due to a clot
Loss of blood due to a ruptured cerebral artery
Symptoms of a Stroke
Weakness/paralysis, loss of vision, difficulty speaking/understanding speech, headache
Risk factors for stroke
Hypertension, atherosclerosis (particularly in the carotid arteries), diabetes mellitus, cigarette smoking, hypercholesterolemia, and atrial fibrillation
Treatment of a Stroke
Medications to dissolve the clot and thin the blood or possibly surgery
