EXAM 3 STUDY GUIDE

How does blood move through the heart?

• bc of pressure gradients

• From high to low

• Left ventricle has higher pressure bc larger distance

• Right = less distance & lower pressure

Where is the tricuspid valve located & when is it open?

• loc between the right atrium & right ventricle

• During ventricular relaxation (diastole- heart resting)— open to let blood flow from right atrium to right ventricle

Where is the bicuspid valve located & when is it open?

• loc between left atrium & left ventricle

• Open during ventricular relaxation (diastole) to. Let blood flow form left atrium to left ventricle

Where is the pulmonary valve located & when is it open?

• loc at the exit of right ventricle between the ventricle & pulmonary artery

• Opened during ventricular contraction (systole - heart pumping out blood) to push deoxygenated blood from right ventricle into pulmonary artery towards the lungs

Where is the aortic valve located & when is it open?

• loc at exit of left ventricle between the ventricle & the aorta

• Open during ventricular contraction (systole- heart pumping out blood) to push oxygenated blood from left ventricle into the aorta towards the rear of the body

Define systole

Phase of contraction

Define diastole

Phase of relaxation & filling

What is diastolic pressure?

• aortic valve closes

• Blood is still leaving aorta, so pressure falls

• Lowest point= diastolic pressure

What is systolic pressure?

• aortic valve opens

• Pressure rises rapidly w/ejection

• Highest point= systolic pressure

• Aortic valve closes Blood

• Backflow of blood causes slight increases- dicrotic notch

What does MAP stand for?

Mean Arterial Pressure

What is MAP?

• average aortic pressure during the cardiac cycle

• Represents the driving force that pushes blood through the systemic circuit

How do you measure blood pressure?

• Tracy peace pressure during ventricular contraction (systolic) & baseline pressure during relaxation (diastolic)

• Measured by mm of mercury (mmHg)

What affects MAP?

• heart rate & contractility

• Blood volume

• Vascular tone

• Arterial stiffness

MAP= CO x systemic vascular resistance (SVR)

What are heart sounds?

• Happen due to turbulent flow when valves close

• first sound— soft “lubb”/ AV valves close simultaneously

• Second heart sound— louder “dupp”/ semilunar valves close simultaneously

What factors affect resistance in a blood vessel?

• Radius of vessel diameter)

• viscosity (thickness) of fluid =n

• Length of vessel

• Poiseuillie’s law

What is Poiseuille’s law?

• R= 8nL/r^4

• Flow= ^PIR

• Therefore: flow= ^Pr^4/8nL

• Basically a rule about the way blood flows

What is the membrane permeability to calcium during the pacemaker potential?

• remains low initially

• Then increases sequentially as T type & later L type Voltage gated Ca2+ channels open as the membrane approaches the threshold (-40mV)

What is the membrane permeability to potassium during the pacemaker potential?

• starts high during repolarization to pull voltage down

• Slowly decreases during phase 4 as K+ channels close

• This reduces hyperpolarizing influence & accelerates the net pos shift

What is the membrane permeability to sodium during the pacemaker potential?

• increases gradually during early- to-mid diastole via funny channels

• Allowing a net inward leak of Na+ that drives the memb potential upward from its max diastolic potential (-60 mV)

How are blood vessels organized?

pulmonary circuit

• supplied by right heart

• Blood vessels from heart to lungs/ lung to heart

• Capillary beds moves carbon dioxide from blood into the air

Systemic circuit

• supplied by left heart

• Blood vessels from heart to systemic tissues/ tissues to heart

• Capillary beds moves oxygen from the blood into the tissues

• Capillary beds moves carbon dioxide into blood from the tissues

What does each blood vessel do?

Arteries— large, branching vessels taking blood away from the heart

Arterioles— small, branching vesssels w/high resistance

Capillaries— site of exchange btwn blood & tissue

Venules— tiny vessels collect blood as it leaves the a capillary beds & merge together to form larger veins

Veins— thin walled vessels carry oxygen poor blood Bach toward heart/ large diameter & one way valves to prevent blood flowing backward against gravity

What is the conduction system of the heart?

• pacemaker cells

• Sinoatrial (SA node)

• Atrioventricular node

• Bundle of His

• Purkinje Fibers

What are the parts of an ECG trace?

P wave— rep atrial depolarization causing them to contract

QRS complex— rep ventricular depolarization causing them to contract (made up of)

• Q wave—- initial downward deflection (septum depolarization)

• R wave— major sharp upward peak

• S wave— downward deflection following the R wave

T wave— rep centricular repolarization

U wave— small occasional wave sometimes seen after T wave, often linked to papillary muscle repolarization or low potassium lvls

How do you measure cardiac output?

CO= HR x SV (heart rate x stroke volume)

How d you measure stroke volume?

SV= EDV - ESV

How do you measure EDV (end diastolic volume?

Volume of blood in ventricle at the end of diastole

How do you measure ESV?

Volume of blood remaining in the event rifle at the end of systole

Ho who you measure MAP (Mean Arterial Pressure)?

MAP= systolic BP + (2x diastolic BP)/3

How do you measure TPR?

TPR= MAP/CO

How do you measure EF (Ejection Fraction)?

EF= (SV/EDV) x 100

EF= (EDV- ESV/EDV) x 100

What is the arrangement of preganlionic Neurons?

• soma resides in brainstem/ spinal cord

• Axon (pregang fiber) thinly myelinated & extends out of CNS to autonomic ganglion in PNS

• Releases ACh

What is the arrangement of postganglionic neurons?

• cell body located in peripheral autonomic ganglion

• Unmyelinated axon extends from gang to target effector organ

Which neurotransmitter is released in the preganlionic neurons?

ACh

Which neurotransmitter is released in the parasympathetic postganglionic neurons?

ACh

Which neurotransmitter is released by sympathetic postganglionic neurons?

Norepinephrine

Which neurotransmitter are released in the adrenal medulla?

ACh onto chromaffin cells

What does Alpha 1 (A1) do?

• Excitation/ contraction

• Raises blood pressure

• Pupillary dilation

• Coupled to G proteins increasing intracellular calcium

What does Alpha 2 do?

• Inhibitory/ negative feedback

• acts as a brake (stops norepinephrine from the nerve terminal)

• Coed G proteins which decrease cyclic AMP

What does Beta 1 do?

• Stimulatory

• increase heart rate, contractility, conduction velocity, stimulates renin release from kidneys

• Coupled G proteins increasing cAMP

What doe Beta 2 do?

• relaxation/ dilation

• causes opening airways

• Delivers extra blood for “fight-or-flight”

• Relaxation of bladder

• Glycogenolysis in liver

• coupled G proteins increasing cAMP

What does Beta 3 do?

• Stimulates breakdown of stored fat into fatty acids for energy

• Coupled to G proteins

What does nicotinic receptors do?

• serves as the electrical “relay point” to pass parasympathetic signal to next nerve

• When ACh binds channels open faster allowing Na+ & K+ to flow across cell memb

• Causes fast depolarization & fires an action potential

What do muscarinic receptors do?

• produce slower metabolic/ physiological responses

What are the muscle fiber types?

• Slow oxidative

• Fast oxidative

• Fast glycolytic

What do slow oxidative fibers do?

• contract slowly

• Rely mostly on oxygen to produce ATP

• Making them highly fatigue resistant

What do fast oxidative fibers do?

• contract quickly

• Use hybrid energy

• Combining oxygen w sugar burning pathways

What do fast glycolytic fibers do?

• contract fast

• Rely strictly on anaerobic sugar burning for quick power

• Fatigue almost immediately