L14 Intro/overview Circulation Flashcards
Components of cardiovascular system
Muscular pump = heart (cardio)
Fluid = blood
Conduits = blood vessels
Together = cardiovascular system
What’s blood?
Plasma (55%)
Buffy coat (<1%)
Leukocytes
Platelets
Erythrocytes (45%)
RBCs
Main functions cardiovascular system
- Gas transport: deliver O2 to tissues and return CO2 to lungs
- Deliver nutrients to active cells or storage sites
- Transport hormones
- Help reg body temp
- Stabilize pH
- Contain cells that fight infection
Why constant need to transport gases around body?
Constant need for energy around body
ATP not stored, must be produced in cells continuously by oxidation of metabolic fuels
Glucose to ATP, use O2
Remove CO2 because it generate H+ and can influence pH
Arterial blood pH
7.45
Cannot survive long w/ pH <6.8 or >8.0
CV, respiratory, and renal systems work together to maintain pH
Acidosis
Denature metabolic enzymes and ion channels
Decrease CNS function can lead to coma, death
Alkalosis
Neurons to hyperexcitable
Tingling, fasciculation, paralysis of respiratory muscles
Heart double pump systems
Serves two circuits / vascular loops
Pulmonary circulation
Systemic circulation
Pulmonary circulation
Right side (RV) pumps deoxygenated blood to the lungs and back to the heart
Right
Deoxygenated
Systemic circulation
Left side (LV) pumps oxygenated blood to the periphery and back to right side
Left
Oxygenated
Cardiac input (CO) =
Venous return (VR)
Heart rate (HR) x stroke volume (SV)
Heart chambers
Right atrium (RA) : receives blood from vena cava
Left atrium (LA) : receives from lungs
Right ventricle (RV) : ejects blood into pulmonary circuit
Left ventricle (LV) : ejects blood into the systemic circuit
Heart valves
Tricuspid and mitral valves: btw atrium and ventricles, prevent backflow into atria when ventricles contract
Pulmonary and aortic valves: btw ventricle and blood vessels, prevent backflow into ventricles when ventricles relax
Tricuspid valve
Right AV valve
Three flaps
Mitral bicuspid valve
Left AV valve
Two flaps
Pulmonary semilunar valve
Btw right ventricular and pulmonary artery
Semilunar flap
Aortic semilunar valve
Btw left ventricle and aorta
Semilunar flap
Systole
Heart muscles contract
Dyastole
Heart muscle relax
Dilation goes to relaxation (to remember)
How does the heart get it’s own blood supply?
Right coronary artery
Left coronary artery
Coronary sinus
Coronary arteries
Supply blood to the myocardium and other components of the heart
Originate from left side of the heart at the beginning (root) of aorta
Most myocardial perfusion occurs during
Diastole
Heart regulates coronary vasodilation or vasoconstriction based upon the hearts oxygen demand
Coronary circulation possesses unique pharmacological characteristics and reactivity to adrenergic stimulation
Blood vessel features
Arteries contain more smooth muscle and elastic fibers (radius proportional to flow, recoil and descent- absorb pressure)
Veins contain valves to prevent backflow which enhances venous return (less elasticity, more collagen for holding volume)
Diameter of blood vessels
Largest - aorta
Smallest- capillaries (1 layer of epithelium for O2 exchange)
What drives blood flow through the rest of body?
Pressure
What’s blood pressure (P)?
Hydrostatic (fluid) pressure
Force of blood exerted against walls of vessels
What determines movement of blood throughout system
What is blood flow (F)?
Volume of blood flowing through a structure per unit time (ml/min)
High P to low P
What’s resistance (R)?
Opposition to blood flow through a vessel
Wide less R
Narrow more R
Pressure profile in the vasculature
Aorta to large arteries , practically no change. Stressed volume
largest drop in arterioles (no elastin, larger cross sectional area)
Veins very low. Unstressed volume
Highest point systole
Lowest point diastole
Pressure profiles btw systemic and pulmonary circulations
Pulmonary RV-25/0 RA-2
Less distance to travel
Less resistance
Stressed to unstressed but on much smaller scale
Systemic LV- 120/0 LA- 5 Drastic distance More resistance Left ventricle wall much thicker Stressed to unstressed
For both largest drop in pressure is at level at arterioles
What determines flow?
Flow= deltaP/R
Flow btw high pressure point to low pressure point is proportional to pressure difference
Resistance relies on area
What affects velocity of blood flow?
v=Q/A
A=pier^2
Flow=Q
To maintain flow btw diff crossectional area velocity has to change
Smaller area - larger velocity (aorta)
Larger area - smaller velocity (capillaries) (to be able to exchange
Blood flow rate is
Identical through all levels
Velocity of flow is inversely proportional to total cross-sectional area
Velocity of flow is slowest in capillaries
Distribution of blood (percentage) in different parts of the circulatory body
System circulation: 84%
Heart:7%
Pulmonary circulation: 9%
Veins, venules: 64% (collagen, hold volume)
Arteries: 13%
Arterioles and capillaries: 7%
Arteries
Conduit vessels
Capillaries
Exchange vessels
Veins
Capacitance vessels
Does blood travel through multiple capillary beds or organs during a single trip around the body?
No because wouldn’t get O2 to all tissues/organs
Parallel and series arrangement of the vessels composing the circulatory system
Vascular beds in parallel- arteries/ veins
Components of circulatory system in series - LA, LV, aorta, vena cava, RA, RV, pulmonary artery, lungs , pulmonary vein
How does blood flow change during exercise?
Skeletal muscle increases 1066%
Heart increases 367%
Skin increases 370%
Digestive tract decreases 56%
Alpha 1 receptor type
All arteriolar smooth muscle except brain
Vasoconstriction
Beta 2 receptor type
Arteriolar snooth muscle in the heart and skeletal muscles
Vasodilation
