EXAM 3: SEC 1/blood Flashcards
Blood
- made of formed elements (cells, cell fragments, plasma)
- plasma carries blood cells, proteins, nutrients, metabolic wastes, and other molecules being transported around the body
Cardiovascular System Overview
- 2 loops: systemic and pulmonary
- closed system
Systemic Loop
- carries blood from heart to the rest of the body
Pulmonary Loop
- carries oxygen-poor blood to lungs and back to heart
Parasympathetic Innervation
- releases acetylcholine through vagus nerve into atria
Sympathetic Innervation
- releases norepi & epi through thoracic spinal nerves and bloodstream into atria and ventricles
P wave
- atrial depolarization
QRS complex
- atrial repolarization
- ventricular depolarization
T wave
ventricular repolarization
Normal open valve heart sound
- quiet and laminar flow
Stenotic valve sound
- turbulent flow
- murmur
Normal closed valve sound
- quiet, no flow
Insufficient valve sound
- leaky valve
- turbulent backflow
- murmur
Positive chronotropic factors
things that increase heart rate
Negative chronotropic factors
things that decrease the heart rate
Regulation of HR
- HR is controlled by the input from the nervous system: SNS increases HR, PSNS decreases HR
- AP created sooner via sympathetic stimulation increases HR creating more positive mem
- AP created later via parasympathetic decreases HR creating negative mem
Frank-Starling Mechanism
- increase ventricular filling/preloading = increase in stroke volume = increase in cardiac output
- decrease preload = decrease stroke volume = decrease cardiac output
- norepi from sympathetic increases intracell calcium concentration increasing contractile force, increasing contractility, faster and stronger contractions and increasing HR with greater force development
2 ways cardiac contractile force is regulated
- starling’s law (the effect of preload) and contractility (the effect of external neural, hormonal stimulation)
Vascular System
- pressure in system falls as passes from one end to other
- pressure in pulmonary circulation is lower than in systemic
upstream pressure systemic
aorta
downstream pressure systemic
right atrium
pulmonary circulation upstream
pulmonary artery
pulmonary circulation downstream
left atria
lowest pressure in heart
right atrium
Arteries
- compliance = change in vol / change in pressure
- the higher the compliance, the more easily can be stretched
- arteries are often called pressure reservoirs because of the elastic recoil - not as compliant as veins
- arteries stretch during systole and relax/squeeze down on blood during diastole
diastole pressure
- lowest pressure
arterial pressure changes due to
age, stiffness, systolic pressure
Active Hypermia
increase metabolic activity of organ to decrease O2, increase metabolites in organ interstitial fluid to arteriolar dilation in organ to increase blood flow to organ
Neural controls
- vasoconstrictors: sympathetic nerves that release norepi
- vasodilators: neurons that release nitric acid
Hormonal controls
- vasocontrictors: epinephrine, angiotensin II, vasopressin
- vasodilators: epinephrine atrial natriuretic peptide
Local controls
- vasocontrictors: internal blood pressure (myogenic response) Endothelin-1
- vasodilators: decrease in O2, K+, CO2, H+, osmolarity, adenosine, eicosanoids, bradykinin, substances released during injury, nitric oxide
All controls go to…
go into arteriolar smooth muscle, altering the arteriolar radius
Capillaries
- the smallest blood vessels
- where gas and nutrient exchange happens by diffusion out of the blood into the tissues (or back into the blood)
- from interstitial fluid/space into capillaries = reabsorption
- movement fluid out of capillaries into interstitial space = filtration
Anatomy of capillary network
- arterioles carry O2 blood into
- capillaries = primary site for microcirculatory exchange
Velocity of capillary blood flow
- velocity is slowest in capillary beds because they have a greater cross-sectional area
- slow velocity flow in capillaries
Diffusion of capillary walls
- down gradient
- rate is fastest for small molecules (Co2 and O2)
- O2 and glucose diffuse down into tissue cells
- CO2 diffuses down and out of tissues into capillary
Net filtration pressure
- fluid pressure in capillary is greater than fluid pressure in interstitial space outside
- fluid pressure gradient promotes filtration
- increase capillary pressure = increase filtration
- decrease capillary pressure = decrease filtration
- increase concentration of solute particles = increase osmotic pressure = decrease water concentration
- decrease solute concentration = decease osmotic pressure = increase water concentration
Blood distribution
- pulmonary circulation = 12%
- heart = 9%
- arteries = 11%
- arterioles and capillaries = 7%
- veins = 61%
Short term regulation of arterial pressure and volume
- involves regulation of cardiac output and peripheral resistance
Arterial Baroreceptors
- stretch receptors sense arterial pressure
- impulses from baroreceptors are carried into CNS
- increase in pressure, causes baroreceptors to stretch, increases afferent impulses, decreasing sympathetic outflow to heart, arterioles, and veins, and increases parasympathetic outflow to heart
Long-term arterial pressure
- circulatory and renal system cooperates to adjust extracellular fluid volume and blood volume to maintain arterial pressure
- increase arterial pressure, increase renal output of solute and water, decrease extracellular fluid and blood volume
- increase blood volume has same affect as above
Hemorrhage and other causes hypotension
- decrease stroke volume
- increase heart rate
- decrease cardiac output
- decrease mean arterial pressure
- increase total peripheral resistance
Upright posture and pressure
- pressure due to gravity = 80 mmHg
- causes blood to somewhat pool in lower limb arteries right after stand up
- reflexes quickly sustain normal
Exercise
- healthy stress on body
- blood flow goes to areas needed most
- decrease flow to brain, increase flow to muscle, same flow to heart, increase flow to skin, decrease flow to kidney and organs
O2 consumption and training
- cardiac output increases in trained vs untrained allowing for more work rate
- heart rate is lower for work rate in trained vs untrained
- stroke volume increases O2 consumption in trained vs untrained
Hypertension treatments
- diuretics
- beta-adrenergic receptors
- CA2+ channel blockers
- ACE inhibitors
- drugs
Diuretics
- increase urine output and decrease extracellular volume decreasing pressure
Beta-adrenergic receptors
- decrease in heart rate and decrease CO and pressure
CA2+ channel blockers
- decrease smooth muscle contraction and lower peripheral resistance
ACE Inhibitors
- decrease overall activity of angiotensin system
drugs
- reduce sympathetic mediated stimulation
Heart Failure
- the greater the degree of cardiac filling, the greater the stroke volume, and cardiac output
- the greater cardiac failure, the greater the expansion of extracellular fluid volume, the greater filling pressure end diastolic volume
- heart failure = stroke volume much less at rest
Coronary Artery Disease and heart attacks
- adequete blood flow to heart is essential
- if flow through vessels is down, O2 needs is not met, and may create heart attack
- atherosclerosis (plaque build up) largest risk factor
- treated via drugs, dilate arteries and veins, drugs that reduce sympathetic NS, drugs that decrease clotting, drugs that control cholesterol
- stents also used to treat if necessary
Eurythrocyte
- red blood cell
- bi-concave disk
- excess surface area
- allows for flexibility and traveling
- 100-120 lifespan days
RBC production
- iron absorbed via GI tract and enters plasma
- transfaren distributes iron around body and to bone marrow
- when blood cells leave, iron stays in spleen
- lack of iron = decrease RBC production = anemia
- circulates = 3 months
- regulation of eurythiopoetin = negative feedback
Hemostasis
- preserve integrity of cardiovascular system and prevent blood loss
Role of liver
- synthesizes bile salts, absorbs vit K, synthesizes clotting factors, allows clotting factors to enter blood
Anticlotting systems
- endothelial cells (thrombin and protein C) and plasminogen activators (plasmin and fibrin)
