Physiology Exam 3

Cardiovascular System

transport system; moves oxygen, nutrients, waste, hormones, drugs, etc.; thermoregulates and undergoes hemostasis

hemostasis

process of forming a blood clot

pulmonary circulation

circulation within the thorax

systemic circulation

circulation through the systems of the body (limbs, brains, digestive, etc.)

hemodynamics

physics of blood flow; goes “down hill”; flows down pressure gradient

blood pathway

left ventricle → aorta → arteries → capillaries → venules → veins → venae cavae → right ventricle

90-93 mmHg or 120/80

average blood pressure/pulsations

aorta (~93 mmHg); venae cavae (~0 mmHg

highest pressure in the _____; lowest pressure in the ___________

pulsatile

BP is _________ in aorta and arteries

BP = BF x R

Ohm’s Law related to BP

Poiseuille’s Law

ohm’s law for blood pressure including added manipulations from body;

BF = ΔPπr² / 8(length)(viscosity)

hydrostatic pressure

influence of gravity and body position on blood

vasoconstriction and dilation

mechanisms to regulate blood flow via resistance

tension; refractory period

no ________ in cardiac muscle action potentials; called long ____________

I_f (funny current)

increases voltage to threshold for action potential

SA node → internodal tract → AV node → bundle of his → bundle branches → purkinje fibers

Cardiac conduction pathway

SA node (72 bpm)

normal pacemaker of the heart

bradycardia

abnormally slow heart rate

tachycardia

abnormally high heart rate

electrocardiography (ECG)

summary of hearts electrical activity

p-wave

atrial depolarization wave of ECG

P-R segment

portion of ECG for conduction through AV node and AV bundle

QRS complex

portion of ECG that correlates to ventricular depolarization

T-wave

portion of ECG that correlates to ventricular repolarization

number of R waves

to detect heart rate using an ECG count ___________

P-V loops

quantify work of heart; tells if heart is adequate/how productive the heart is; (pressure and volume); travel CCW

A (P-V loop)

start of loop, opening of mitral valve (left AV); volume increases no change in pressure

A’ (P-V loop)

closing of mitral valve once full of blood; left ventricle full

B (P-V loop)

left ventricle contracts; EDV (end-diastolic volume); pressure increases, no volume change

C (P-V loop)

blood goes to aorta; aortic semilunar valve opens (isovolumic contraction); volume decreases, minor change in pressure

D (P-V loop)

isovolumic relaxation; closing of semilunar valve; ESV (end-systolic volume); pressure decreases, no volume change

Wiggers Diagram

summary of all events of a cardiac cycle; everything your heart does in one beat; includes ECG, pressure graph, and volume graph

stroke volume

EDV-ESV = 135-65 = 70mL pumped in one beat

diastolic

relaxation

systolic

contraction

Cardiac Output (CO)

HR * SV = VR (needs to be equal)

venus return (VR)

amount of effort (lower when relaxed); adjust based on demand

intrinsic regulation

starlings law and bainbridge reflex; regulates how hard heart works

starlings law

heart is designed to pump whatever volume of blood is sent; length to tension relationship of cardiac muscle (more tension = more optimum overlap of myosin and actin)

bainbridge reflex

increase in venus return causes increase in heart rate (regulation)

extrinsic regulation of HR

how autonomic NS regulates HR; medulla oblongata has cardiovascular control center

extrinsic regulation of contractility

cardiac muscle has graded contractions regulated by epinephrine and norepinephrine

beta blockers

lowers high HR; slow down natural pacemaker; blocks beta receptor; decreases force of contraction and rate of funny current in SA node

skeletal muscle pump

helps return blood to the heart from the lower body via veins; muscle contraction compresses veins; one-way valves in veins keep blood flow in one direction; requires movement

respiratory muscle pump

increase venus return upon inspiration (diaphragm contracts “inhale”) due to decreased thoracic pressure

preload

extent of myocardial stretch in ventricle (before it contracts); more blood in ventricle; more you fill the greater the force of contraction (more “stretch”)

afterload

force ventricle needs to overcome blood in chamber and pressure in aorta; ventricle full of blood need to contract and push blood into aorta but aorta has high pressure (resistance); high BP makes this more difficult (more resistance = higher afterload)

ejection fraction

% of blood pumped/ejected in one heartbeat (~60%); higher heart rate causes this to increase

tunics

layers of blood vessels; tunica externa, media, and intima

vasoconstriction and dilation

mediated by SM of tunica media and sometimes epithelium; decrease/increase in diameter of blood vessels

microcirculation

made up of small blood vessels and capillaries; capillaries open or closed

blood pressure

pulsatile recording; 120/80; SBP and DBP; PP = SBP - DBP

MAP

mean arterial pressure; DBP + 1/3 PP; average pressure in the arteries over one cardiac cycle

hydrostatic pressure

influence of gravity and fluid volume on blood pressure

sounds of korotkoff

indirect measurement of BP using turbulent vs. laminar flow

baroreceptors

pressure receptors; acute regulate of BP; found in aortic arch and carotid sinus have these

chronic regulation of BP via kidneys

removes waste; utilizes water to do this (takes water from blood); alters volume of blood via urine output

pressure diuresis

pee more (urine output in response to inc. in BP)

pressure naturesis

inc. in Na+ excretion in response to inc. in BP (if Na+ in urine, water follows, causes BP to dec.)

autoregulation

blood flow is _______; myogenic and metabolic (match Q demand); only works in small arteries and arterioles

vasocontrictors

norepi., epi., vasopressin

vasodilators

ACh, Epi, Adenosine

reactive hyperemia

increase blood flow to compensate for something

ischemia

pathologic decrease in blood flow

active hyperemia

increase in blood flow to a tissue when its metabolic activity rises

capillarties

site of nutrient and waste exchange; continuous, fenestrated, or sinusoidal

continuous capillaries

dominant capillary form, found in most of the body, no pores instead have small cell junctions that allow water and small solutes to pass through; found in lungs and skin

fenestrated capillaries

capillaries found in kidneys and intestines, contain large pores for transcytosis to occur

sinusoidal capillaries

capillaries containing very large pores/gashes/clefts that allow for leakage; high permeability; found in liver and bone marrow

transcytosis

process in capillaries where proteins and macromolecules are brought across the endothelium

starling’s forces

determine net filtration/absorption of capillaries; hydrostatic and osmotic pressure; filtration must = absorption to keep blood volume the same

hydrostatic pressure (30 mmHg)

outwardly directed pressure; favors filtration

osmotic pressure (25 mmHg)

represented by pi; oncotic pressure, inwardly directed, favors absorption

albumin

plasma protein, stuck in capillary, function is to draw water from interstitial fluid to mix with blood

3 liters

net average of ______ a day of fluid filters out of the capillaries

lymph (2-3 L/day)

fluid inside lymph vessel/node; recycled with venous blood

4-8 minutes

normal clotting time

vasoconstriction, platelet plug formation, blood coagulation cascade

3 phases of hemostasis

vasoconstriction

local constriction to slow down blood flow; release thromboxane A2 to contract smooth muscle

platelet plug formation

forms “cork” to slow down blood flow; platelets stick together

blood coagulation cascade

makes blood clot water tight; many clotting factors contribute

clotting factors

what is responsible for activating thrombin in blood coagulation cascade

cardiac muscle

striated, involuntary, mononucleated, regulated intrinsically, neural, endocrine, and paracrine

contraction of cardiac muscle

involved troponin, sarcoplasmic reticulum, utilize Ca2+ from ICF and ECF (skeletal only ICF), graded unlike skeletal muscle

phospholamban

regulatory protein that alters sarcoplasmic reticulum Ca2+ -ATPase activity