cardiovascular phgy from slide 160-236 Flashcards
What is flow equivlent to in terms of perfusion pressure?
what is always kept constant in this formula, what is this called?
=perfusion pressure/R= Pa/R= MAP/R
-keep flow constant despite fluctuations (autoregulation)
What is it called when we minimize fluctuations in Pa in the flow formula?
What factors affect flow of blood in organs?
-neuro-hormonal control
-MAP (Mean arteriole pressure) and resistance
What happens to blood flow to organs during excercise, what part of the body is adjusting the flow?
-as we excercise the blood to muscles increases as there is a dilation in the veins
-flow adjustment is done by brain and hormones in blood system
How do you calculate resistance and total peripheral resistance?
What is the formula for MAP?
-R=perfusion pressure/flow
-TPR=MAP/CO
-MAP=COTPR
=HRSV*TPR
What is the value of MAP and pulmonary vein pressure, what is the perfusion pressure?
What is the difference between pulmonary circulation and systemic circulation in terms of numbers?
-MAP=15 mmhg
-pulmonary pressure=5mmhg, perfusion pressure=10mmhg
-systemic circulation has a high P and high R whereas pulmonary circulation has a low P and low R, and is 10x smaller resistance than systemic ciruclation but they have the same flow
What is the definition of autoregulation?
What is the first branch off the aorta, how is pressure controlled in arteries?
What does the first branch off the aorta provide to the cardiac muscle?
-organs defending themselves against changes in BP
-corony arteries are the first branch off the aorta
-pressure is controlled by a pump
-first branch off supplies oxygen, and nutrients to cardiac muscle and removes waste
What happens during coronary autoregulation when the perfusion pressure goes down, but flow is maintained?
How are the vessels altered to maintain flow?
-resistance to flow is reduced
-organs sense a pressure drop and cause a dilation of small arteries and arterioles to bring flow back to normal even though P has dropped
What is the autoregulatory range pressure?
How does flow change when pressure changes?
-between 30 mmhg and 200 mmhg
-flow remains flat while pressure changes
What causes the 2 mechansims of autoregulation to be active?
What are the names and mechanism of the 2 methods?
-decrease in arterial pressure in organ (PP drops), causes decrease in blood flow to organ
-metabolic response is caused by decrease in O2 and increase in metabolites
-myogenic response is decrease in vessel wall stretch in organ
What do the 2 methods of autoregulation lead to, in order to fix the issue?
How does the dilation help?
-arteriolar dilation in the organ, and restoration of blood flow toward normal in organ
-SM dilation causes a fall in resistance and an increase in flow
What happens to the local metabolic control during excercise, what increases/decreases in the 4 steps?
What is hyperemia?
what type of pump does the brain have?
-increased metabolic activity –> decreases O2 and increased metabolites in organ interstital fluid—>arteriolar dilation in organ—>increased blood flow in organ
-hyperemia is increased blood flow which occurs with excercise
-sodium potassium pump to ensure enough of it in the cell
What is the influence of autonomic nervous system on the heart and adrenal glands?
What are the 2 branches?
-involuntary nervous system
-the 2 branches are parasympathetic (rest and digest) and sympathetic (fight or flight)
What is the formula for cardiac output (CO) and MAP?
What happens to HR when we excercise harder?
-CO=HRSV
-MAP=COTPR
-CO will increase and thus HR goes up, which will alter MAP
What type of hormone does the SA node have the parasympathetic vs sympathetic side?
sympathetic side=norepinephrine (NE) (increases HR)
-parasympathetic side=acetylcholine (ACh) (slows down HR)
What binds to receptors on the ganglionic cell bodies, what is another name for the receptor?
-What happens after binding?
-What is the ACh receptor on the SA node called
-ACh binds to ganglionic cell bodies (nicotinic receptor)
-ACh is released in neurotransmitters
-muscarinic receptor since it is also activated by muscarine
What happens when the parasympathetic nervous system is stimulated?
-What happens to the HR?
-we release more ACh and binding to ganglionic cells causing more AP to travel in post ganglionic axon and more ACh being dumped into SA node cell
-causing a decrease in HR
Where is the cell body in parasympathetic control?
Where are the ganglia?
-where is the long chain axon going to/from?
-where is the short chain axon going to/from?
-cell body is in brain stem
-ganglia are close to heart
-long chain is from spinal cord to ganglia
-short chain from ganglia to heart
When do we use atropine?
what does it bind to, and what does it cause?
-used if someone’s HR is too low
-atropine binds to muscarinic receptor to stop ACh from binding and cause an increase in HR
What is the neurotrasmitter in sympathetic nervous system?
-What does it bind, and cause?
What is a beta agonist?
What is a beta antagonist (beta blocker)?
-neurotrasmitter is noreepinephrine (NE)
-binds to Beta adrenergic receptor then the HR will increase
-beta agonist is used to bind to NE and increase HR
-beta antagonist is used to decrease HR since it blocks the NE receptor from binding
Where is the cell body in sympathetic system?
-where is the long chain axon going to/from?
-where is the short chain axon going to/from?
-cell body is in spinal cord not the brain stem
-long axon goes from the ganglia to the heart
-short axon goes fro spinal cord to ganglia (opposite of parasym.)