Cardiovascular Hemodynamics Flashcards
beta blocker: mechanism of action
Decreases stimulation of beta-adrenergic receptors in the heart and blood vessels
result of beta blocker
Decreased HR and SV
Vasodilation
calcium channel blocker: mechanism of action
Decreases intracellular calcium in the heart and blood vessels
result of calcium channel blocker
decreased HR and SV
Vasodilation
Angiotensin Converting Enzyme (ACE) inhibitor: mechanism of action
Decreases conversion of angiotensin I -> angiotensin II
result of Angiotension Coverting Enzyme inhibitor
Decreased production of aldosterone
Increased urinary excretion of sodium and water
Vasodilation
diuretic: mechanism of action
increases urine output
result of diuretic
Decreased cardiac output
Angiotensin II Receptor Blocker (ARB): mechanism of action
Decreases receptor binding of angiotensin II
result of angiotension II receptor blocker
Decreased stimulation of aldosterone secretion
Increased urinary excretion of sodium and water
Vasodilation
renin inhibitor: mechanism of action
Inhibits the binding of renin to angiotensinogen
results of renin inhibitor
Decreased production of angiotensin II and stimulation of aldosterone secretion.
Increased urinary excretion of sodium and water
Vasodilation
Baroreceptor Reflexes alter BP
- carotid sinus reflex
- aortic reflex
carotid sinus reflex
- Baroreceptors in walls of carotid sinuses
- Helps regulate BP in brain
- Signals sent via cranial nerve IX (glossopharyngial nerve) to the CV center in medulla oblongata
aortic reflex
- Baroreceptors in walls of ascending aorta and aortic arch
- Helps regulate systemic BP
- Signals sent via cranial nerve X (vagus nerve) to the CV center in medulla oblongata
carotid sinus reflex regulates
BP in brain
carotid sinus reflex signal sent via
cranial nerve IX to the CV center in medulla oblongata
aortic reflex helps regulate
systemic BP
aortic reflex signals sent via
cranial nerve X to the CV center in medulla oblongata
sense degree of stretch in vessels
baroreceptors
decreased stretch
decreased BP
increased stretch
increased BP
affects rate that nerve impulses are sent to the CV center in medulla oblongata
degree of stretch
results in a slower conduction of nerve impulses to the CV center
decreased stretch
results in a faster conduction of nerve impulses to the CV center
increased stretch
responds by changing the balance between PNS and SNS stimulation of effector organs
CV center
elicits efferent output that decreases PNS tone and increases SNS tone
Slower conduction of nerve impulses to the CV center
result of slower conduction of nerve impulses to the CV center elicits efferent output that decreases PNS tone and increases SNS tone
blood pressure increases
elicits efferent output that increases PNS tone and decreases SNS tone
faster conduction of nerve impulses to the CV center
result of faster conduction of nerve impulses to CV center elicits efferent output that increases PNS tone and decreases SNS tone
blood pressure decreases
blood volume in supine
blood volume distributed throughout the body
blood when going from supine to standing
shift from greater than 500 mL of blood to the lower body
autonomic nervous system response when going from supine to standing
baroreceptor reflex activation of the SNS
healthy subject: supine to standing
- normal compensatory response
- NE release signals for BP and HR increases
- cerebral perfusion is maintained
patient with nOH: supine to standing
- insufficient NE response due to autonomic dysfunction
- inadequate BP increases and minimal HR changes
- reduced cerebral perfusion causes symptoms (dizziness)
filtration
movement of fluid from tissue capillaries to tissue interstitial space
reabsorption
movement of fluid from tissue interstitial space to tissue capillaries
pressure driving filtration
promoted by blood hydrostatic pressure (BHP) and interstitial fluid osmotic pressure (IFOP)
primary filtration pressure
blood hydrostatic pressure
primary reabsorption pressure
blood colloid osmotic pressure
pressure driving reabsorption
promoted by blood colloid osmotic pressure (BCOP) and interstitial fluid hydrostatic pressure (IFHP)
net filtration pressure (NFP)
difference between filtration and reabsorption pressures
NFP indicates
direction of fluid movement, determining whether fluid enters or leaves capillaries
NFP=
filtration - reabsorption
fitration: atrial end net filtration pressure = 10 mmHg
fluid exits capillary since capillary blood hydrostatic pressure is greater than blood colloid osmotic pressure
mid capillary net filtration pressure = 0 mmHg
no met movement of fluid since capillary blood hydrostatic pressure is equal to blood colloid osmotic pressure
reabsorption: venous end net filtration pressure = -7 mmHg
fluid re-enters capillary since capillary blood hydrostatic pressure is less than blood colloid osmotic pressure
lymphatic system
Network of lymph, lymph vessels, lymph nodes, and lymphatic organs
lymphatic system: transport
One-way transport system for fluid, proteins, and other substances
lymphatic system: collection and return of fluid
Collect fluid from the interstitium and return to the bloodstream
lymphatic system major functions
- Regulation of tissue fluid balance
- Transport route for immune cells, tumor cells, hormones, nutrients, waste products, proteins, and other molecules
- Lipid absorption and transport from the gastric system
- Removal of cellular debris
- Reservoir for proliferating white blood cells and tumor cells (lymph nodes)
Lymphatic System Structures and Components
- Lymph
- Lymph vessels
- Lymph nodes
- Lymphatic organs/tissues
examples of lymphatic organs/tissues
- spleen
- thymus
- tonsils and adenoid
- bone marrow
lymph
Fluid that travels throughout the body via a network of lymphatic vessels
formation of lymph
when interstitial fluid moves into lymphatic capillaries
lymph composition
96% water and 4% solutes
examples of lymph solutes
Various proteins, lipids, glucose, urea, creatinine, amino acids, electrolytes, and lymphocytes
lymph vessels
Transport lymph throughout the body
lymphatic capillaries
small, closed-ended tubes through which fluid from tissues enters the lymphatic system
Lymphatic vessels
move lymph to and from lymph nodes
lymphatic vessel types
Pre-nodal vs. post-nodal (afferent vs. efferent)
lymphatic vessels valves
aid in one-way propulsion of lymph
lymphatic vessels: segments of lymphatic vessels between valves form
contractile compartments
collecting ducts
return lymph to the bloodstream
allows lymph to access blood
nodal vasculature
propel lymph to the next compartment
contraction of contractile compartments
Lymphatic vessels converge into
lymphatic trunks which then become the collecting ducts
fundamental process that removes excess water and plasma proteins from the interstitium
contraction-relaxation cycle of the lymphatic bulbs at the end of the lymphatic capillaries
Pressures along the lymphatics
lymphatic vessel contractions and by organ movements
lymph nodes
Filter and remove harmful substances from lymph before returning it to the bloodstream
cervical lymph node location
neck
Thoracic and mediastinal lymph nodes location
chest
axillary lymph node location
armpits
Para-aortic, peri-aortic, and mesenteric lymph nodes location
abdomen
Inguinal lymph nodes location
groin
cells that activate the immune system
lymphocytes and macrophages
symptoms when large number of particles are filtered through a lymph node
swelling and tenderness
spleen
largest lymphatic organ; removes worn out red blood cells, lymphocytes, and foreign invaders; stores red blood cells and lymphocytes
thymus
site where T lymphocytes mature and multiply
tonsils and adenoid
trap bacteria and viruses
bone marrow
site of hematopoiesis
formation of lymph
More fluid is filtered than is reabsorbed, so the excess fluid is taken up by the lymphatics
important function of lymph
help return plasma proteins back into the bloodstream
lymphatics important role
removing the excess interstitial fluid
affect of lymphatics NOT removing excess interstitial fluid
tissues would become swollen with fluid
Mechanisms that facilitate transport of lymph
- Valves to prevent backflow
- Smooth muscle contractions in the lymphatic vessel walls
- Intrathoracic pressure changes during breathing
- Pulsations of nearby arteries
- Skeletal muscle contractions
- Movement of adjacent tissue
interstitial pressures being higher than the lymphatic capillaries
- Fluid moves into the lymphatics
- forces open the minivalves
contraction-relaxation cycle of the lymphatic bulbs
fundamental process that removes excess water and plasma proteins from the interstitium
Pressures along the lymphatics are generated by
lymphatic vessel contractions and by organ movements
edema
An abnormal increase in interstitial fluid if net filtration exceeds net reabsorption
3 examples of edema
- result of excess fluid filtration
- result of inadequate fluid reabsorption
- result of decreased removal of excess filtrate by lymphatic system
edema: result of excess fluid filtration
- Increased capillary permeability due to injury or inflammation (i.e. burns, allergic reactions, etc.)
- Fluid buildup due to an obstruction such as a clot
- Fluid buildup due to a weakened heart (i.e., congestive heart failure)
edema: result of inadequate fluid reabsorption
Decreased concentration of plasma proteins lowers BCOP
edema: result of decreased removal of excess filtrate by lymphatic system
Fibrosis and scarring of lymph nodes and lymphatic vessels
kidney and liver disease can cause
edema
kidney and liver disease can cause edema due to
Low protein levels in the blood caused by malnutrition
edema: CHF
effects of heart failure on blood flow, leads to increased blood hydrostatic pressure, and therefore edema
pulmonary edema symptoms
SOB, rapid breathing, fatigue, dizziness, weakness
peripheral edema symptoms
- difficulty breathing
- SOB with exertion of laying in bed
- fainting or dizziness
- coughing blood
seek immediate care leg swelling: edema
- Occurs suddenly and for no apparent reason
- Is related to a physical injury, such as from a fall, a sports injury or a car accident
- Occurs in one leg and is painful, or is accompanied by cool, pale skin
Nonemergency problems related to leg swelling (edema)
Leg swelling that is the side effect of a drug can look just like leg swelling caused by a kidney disorder. Make an appointment as soon as possible so that your doctor can diagnose the underlying problem
tips for leg swelling with edema
- Restrict the amount of salt in your diet.
- Put a pillow under your legs when lying down, which may lessen swelling related to the buildup of fluid.
- Wear elastic compression stockings, but avoid stockings that are tight around the top (if you can see the indentation from the elastic, they may be too tight).
- If you need to stand or sit for long periods, give yourself frequent breaks and move around, unless the movement causes pain.
- Don’t stop taking a prescription medication without talking to your doctor, even if you suspect it may be causing leg swelling.
- Over-the-counter (nonprescription) pain medication may lessen painful swelling
Ascites
Edema in the peritoneal cavity of the abdomen
ascites most commonly seen in
individuals with cirrhosis of the liver
ascites: Increased pressure in the hepatic portal vein due to cirrhosis leads to
fluid leakage out of the vasculature
Fluid leakage out of the vasculature due to
inflammation
ascites symptoms
As more fluid accumulates, increased abdominal girth and size are commonly seen. Abdominal pain, discomfort, and bloating are also frequently seen as ascites becomes larger. Shortness of breath can also happen with large ascites due to increased pressure on the diaphragm and the migration of the fluid across the diaphragm causing pleural effusions (fluid around the lungs). A cosmetically disfiguring large belly, due to ascites, is also a common concern of some patients. If ascites is causing symptoms of shortness of breath, abdominal discomfort ,or inability to do normal daily tasks such as walking, the patient’s primary doctor should be notified.
lymphedema
Progressive swelling that occurs when protein-rich fluid accumulates in the interstitium
primary lymphedema
Genetic and familial abnormalities in lymphatic structures or function
secondary lymphedema
Secondary to damage of lymphatic structures
Alterations in lymph transport mechanisms and/or lymphatic structures
- Fibrosis that impedes muscle movement
- Fibrotic lymph nodes
- Removal of lymph nodes and vessels
impede lymph flow: physiological mechanisms
Variations in capillary and interstitial pressures
