Week 9 Flashcards
What controls Skeletal muscle Blood flow?
- SYM innervation
- Local metabolites
What control dominates at Rest in Skeletal muscle flow?
SYM inneravtion
- a1: NE, Vasoconstriction (dominant)
- B2: E, Vasodilation (fight-flight)
What control dominates during Exercise in Skeletal muscle flow?
Local Metabolites
Functional Hyperemia
Increase in tissue perfusion due to presence of Metabolites
Reactive Hyperemia
Increase in tissue perfusion following short period of Ischemia
Skeletal Blood flow REST
1L / min
(20% of CO)
Skeletal Blood flow EXERSISE
20 - 30L / min
Skeletal Blood flow AVDO2
(rest & exercise)
- Rest: 60ml / L
- Exercise: 150ml / L
Splanchnic Circulation Flow rate (Qs)
1500ml / min
Which local metabolites trigger vasodilation in skeletal muscle during exercise?
Decreased pO2, increased pCO2, increased lactate (decreased pH), increased K+, and increased adenosine (from ATP metabolism).
2 main functions of splanchnic circulation?
- Site of adjustable resistance
- Major reservoir of blood
How do local hormones like CCK and Neurotensin affect splanchnic blood flow?
Increase local blood flow.
(especially after meals, to support digestion and nutrient absorption)
What is postprandial circulation in the splanchnic system?
Increase in blood flow to the GI tract (after a meal) to support metabolic needs and nutrient absorption
(7-8x increase)
What controls Blood flow in coronary circulation? (+ most importrant)
Local Metabolites
MOST IMPORTANTLY Adenosine & Hypoxia
Coronary Blood flow (Qc)
- Resting: 200 - 250ml / min
(5% of CO 5.6L/min) - Exercise: 1250ml / min
Coronary AVDO2
- Resting: 120 - 130ml / L
- Exercise: 900 - 1200ml / L
O2 consumption of Heart
30ml /min
When does most Coronary circulation take place?
Diastole
80% of Coronary circulation
Myogenic Mechanism
- Increased pressure, Vasoconstriction, less perfusion
- Decreased pressure, Vasodilation, more perfusion
What controls Blood flow in Brain circulation? (+ most importrant)
Local Metabolites
CO2 & H+ by central chemoceptors
Cerebral Circulation Blood flow (QB)
750 - 800ml / min
(15% of CO)
Cerebral Circulation AVDO2
60ml / L
What volumes are always constant in the Skull?
- Brain Tissue Volume
- Blood Volume
- CSF Volume
What Glut transporter is in the brain?
GLUT-1
CSF Volume
150 ml
CSF Production in a day
550ml / day
CSF compared to Blood
- Lower K+
- Lower Protein Content
- Lower pH
CSF Pressure
100 mmH2O
How much O2 provided by lungs
240 - 280 ml / min
How much CO2 eliminated by lungs
190 - 220 ml / min
ACE1
Converts Angiotensin I to Angiotensin II
VASOCONSTRICTION
ACE2
Converts Angiotensin II to Angiotensin (1-7)
VASODILATION
Dichotomous division of Lungs
20 - 23 divisions (2^20-23)
First division of Lungs
1 - 17
No gas exchange
(Conducting/Dead zone)
Second division of Lungs
17 - 23
Gas exchange
(Respiratory/Alveolar space)
How many alveoli? (area)
300 million
70 - 90 m2
Type I Pneumocytes
Surface
(Gas exchange)
Type II Pneumocytes
Surfactant
What does Vital capacity consist of?
- IRV
- TV
- ERV
What makes up Total Lung capacity
- Vital Capacity (IRV, ERV, TV)
- RV
What makes up Functional Residual Capacity (FRC)
- ERV
- RV
Tidal Volume (ml)
500 ml
Peak Expiratory Flow Rate (PEFR)
8L / sec
Intrapleural Pressure
REST -2 cm H2O
INH -5 cm H2O