chapter 15 Flashcards
Blood volume difference
Male blood - 5 litters in males
Femal blood - 4 litters in females
Circulate all litters of blood per minute
Blood vessel structures
Arteries- Biggest
- Act as pressure reservoir
- Thick layers of vascular smooth muscles
- Lots of elastic and fibrous connective tissue
Arterioles
- Site of variable resistance
- Part of the microcirculation
- Less elastic and more muscular
Metarterioles - Smallest
- Branches of arterioles
- Partial smooth muscle layer
- Precapillary sphincters open and close to direct blood flow to capillaries or venous circulation
Angiogenesis
development of new blood vessels
- Necessary for normal development
- Enhances heart and skeletal muscle blood flow
Capillaries
Thinnest walls
single layer of epithelial cells
support - basal lamina
density is related to metabolic activity
Venules
Receive blood from capillaries
Thin exchange epithelium
Little connective tissue
Convergent pattern of flow
Veins
Thin walls of vascular smooth muscles
Contain one-way valves, prevent backward flow
More numerous than arteries
Lie closer to the body surface
Less elastic tissue
Veins
Thin walls of vascular smooth muscles
Contain one-way valves, prevent backward flow
More numerous than arteries
Lie closer to the body surface
Less elastic tissue
Site of exchange for blood and interstitial fluid?
Capilaries and postcapilary venules
inner layer is endothelium
secretes paracrine factors
Regulates blood pressure, blood vessel growth, and absorption
How does blood flow?
Ohms Law
Flow = pressure/resistance
or
Q = MAP / R
if mmHg (P) is the same then flow is the same
Flows when there is a + pressure gradient, does not depend on absolute P
Posouilles Law
R = resistence
v = viscosity
l = length
r^4 = radius
R = 8lv / r4π
Total Cross sectional
increases as blood vessels branch
Each branching vessel is smaller but the combined diameter (total area where blood can flow) is greater!
Velocity of blood
as CSA increases, Velocity will decrease
TPR
Total peripheral resistance
greater TPR = Harder for blood to flow
Length, viscocity and diameter effect resistence*
TPR
Total peripheral resistance
greater TPR = Harder for blood to flow
Length, viscocity and diameter effect resistence*
What Effects MAP
blood Volume
Cardiac output
Resistence of blood flow
Distribution of blood b/w venous and arterial vessels
MAP = QxR
or
MAP - DIA + (1/3 (SYS-DIA))
Q=Cardiac output
DIA = Dialstolic Pressure
What maintains blood flow during ventricular relaxation
elastic systemic arteries
Pulse pressure
SYS-DIA
MATH SV, Q, EF%
SV = EDV - ESV
Q = HRxSV
EF = (SV / EDV) x 100
MATH SV, Q, EF%
SV = EDV - ESV
Q = HRxSV
EF = (SV / EDV) x 100
Desirable Blood Pressure
120/80 (SYS and DIA) or less
Desirable Blood Pressure
120/80 (SYS and DIA) or less
Hypotension vs Hypertension
MAP
Hypotension is lower than normal M A P, hypertension is higher than normal M A P
Hyperemia
Local increase in blood flow
active - Increases metabolism, increases blood flow, Arterioles dialate, Nutrient and )2 supply to tissue would increase
Influences of Arteriole resistence
Locally or systematically controlled
Myogenic autoregulation
adjusts blood flow
Paracrine signals
influence vascular smooth muscle.
Released and reacts close by
secreted by epithelium or cells
What system effects vessel diameter
Symoathetic system
Catecholamines: Types
Nuerotransmitter - norepi
Neurohormone - epi
Specificity of receptors eg
Only adregenic receptors bind to the two types of catacholamines
Catecholamines: Receptors
Alpha receptors—most common symp receptor—respond strongly to NE
β1-receptors- respond equally strongly to norepinephrine and epinephrine.
β2-receptors more sensitive to E
Tonic modulation
Signals increase = vessels constrict
Signals decrease = vessels dialate
B2
location
Sensitive to Epi
Found in vessels leading to heart, skeletal muscle, and liver
B2
location
Sensitive to Epi
Found in vessels leading to heart, skeletal muscle, and liver
EPi effect on different receptors
released by adrenal medulla
a1 = consriction
B2 = dialates
Kidney is responsible for
Removing excess fluid
If blood volume decrease, then pressure decreases
Lost fluid volume compensated through drinking (slow) or
intravenous infusion (rapid)
Vasoconstriction and (rapid)
Sympathetic stimulation of heart (rapid)
