Physiology wk5 Flashcards by Daniel Baxter

what is the purpose of the cardiopulmonary/cardiorespiratory system

Transport of o2 and nutrients to tissues
Removal of co2
Regulation of body temp

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what are the two adjustments of blood flow during exercise

increased cardiac output
redistribution of blood from inactive organs/digestive system

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what is included in the circulatory system

heart – creates pressure to pump blood
Arteries and arterioles – carries blood away from heart
Capillaries – exchange of o2,co2 and nutrients with tissue
Veins and venules – carry blood toward the heart

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what wall components make up blood vessels

Smooth muscle
Collagen
Elastin
Endothelium

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physical characteristics of blood include

Plasma – liquid portion of blood, contains: ions, proteins and hormones
Cells –
* red blood cells erythrocytes (contains HB)
* White blood cell (prevent infection
* Platelets (blood clots)
Haematocrit – percentage of blood composed of erythrocytes (amount that is RBC)

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what does resistance refer to

measure of hinderance or opposition to blood flow, caused by friction

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what is total peripheral resistance

sum of resistance to flow in all individual organs

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what is the relationship between pressure difference, resistance and blood flow

Blood flow is directly proportional to the pressure difference the two ends of the system and inversely proportional to resistance

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what is the formula for blood flow

change in pressure / resistance (darcy’s law)

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what does resistance depend upon

length of the vessel
viscosity of blood
radius of vessel

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what is the formula for resistance

length x viscosity / radius ^4

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what is the formula for MAP

MAP = CO (cardiac ouput???) x Total peripheral resistance

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what is local vascular resistance

resistance of blood flow from a single vessel

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what is poseuille’s law

radius^4 is inversely proportional to resistance

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what are two sources of resistance

MAP decreases throughout the systemic circulation
Largest BP drop occurs across the arterioles

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how does respiration contribute to aerobic performance

O2 diffusion
Ventilation
Alveolar ventilation
Hb-o2 affinity

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how does central circulation contribute to aerobic performance

Cardiac output
Arterial blood pressure
Hb conc

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how does peripheral circulation contribute to aerobic peroformance

Flow to non-existing regions
Muscle blood flow
Muscle capillary density
O2 diffusion
Vasvualr endurance
O2 extraction
O2-Hb affinity

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how does muscle metabolism contribute to aerobic performance

Enzymes and oxidative potential
Energy stores
Myoglobin
Mitochondria
Muscle mass/fibre types
Substrate delivery

what is arteriovenous difference

amount of o2 taken up from 100ml of blood

what is ficks equation

relationship between cardiac outpt, vo2 diff and vo2
vo2 = q x a-vo2 differnece

what afferent feedback influences the cardiovascular system

heart mechanoreceptors
muscle chemoreceptors – muscle spindles and golgi tendon organs, sensitive to force ans sped of contraction
baroreceptors

what is the exercise pressor reflex

peripheral feedback to the medulla oblongata to amend cv response to exercise

what happpens to the baroreflex during exercise

it becomes inactive and rests in order to not confuse the body when increasing blood flow

what is the structure of the heart wall

* Epicardium - lubricative outer layer * Myocardium - provides muscular contractions that eject blood from chambers * Endocardium - protective inner lining of chambers and valves

what is a myocardial infraction

* Blockage in coronary blood flow results in cell damage * Exercise training protects against heart damage during an MI

what are some structural differences between heart and skeletal muscles

Heart muscke fibers are shorter and branched Heart muscles only have a singular nuclei compared to multiple in muscle Skeletal muscles have no cellular junctions, the heart does heart action is involuntary heart muscles have the potential to be regenerative

what are the 4 steps of the conduction system within the heart

1. SA node – pacemaker, initiaties depolarization 2. AV node – passes depolarization to ventricles, delay allowing for ventricular filling 3. Bundle branches – connect atria to ventricles 4. Purkinje fibres – spread way wave of depolarization throughout ventricles

from the AV node where do the impulses move to

moves through ‘fibrous skeleton’ and into the intraventricular septum

what are the components of an ECG

P wave – atrial depolarization QRS complex – ventricular depolarization and atrial repolarization T wave – ventricular repolarization

what happens in systole

the intraventricular pressure rises as the ventricles contract, this pressure falls as the ventricles relax. The pressure is what opens the valves to allow blood to move through the heart

what are the uses of the ECG

* evaluate cardiac function * Look for atherosclerosis * S-T segment depression

what is myocardial ischemia

reduced blood flow to myocardium

how does the parasympatheitc system work

works via vagus nerve to slow HR by inhibiting SA/AV node (ACH

how does the sympathetic system work

works via cardiac accelerator nerves to increase HR by stimulating SA/AV node (norepinephrine)

what does chronotropic mean

heart rate increases

what does inotropic mean

contractility increases

what controls coronary blood vessels

Control of coronary blood vessels are mainly metabolic, the main metabolic vasodilator is adenosine

what is cardiac arrest

sudden unexpected loss of contractile function of the heart

what life support measures do you use during cardiac arrest

* CPR * Chest compressions * AED – electric shock

what does Vfib refer to

ECG is too small

what does VT refer to

ECG too large

increased need for o2 is achieved through

* Increased cardiac output * Redistribution of blood flow from inactive organs to skeletal muscles

what is end diastolic volume EDV

* volume of blood in the ventricles at the end of diastole (preload) * venous return * frank-starling mechanism (increased stretch of ventricles)

what is average aortic pressure

pressure the heart must pump against to eject blood (afterload)

what is strength of ventricular contraction enhanced by

* circulating epinephrine and norepinephrine * direct sympathetic stimulation of the heart