Human Physiology Exam 4

Pulmonary circuit

right side
recieves oxygen-poor blood from body tissues
Pumps to the lungs to get rid of CO2 and pick up O2

Systemic circuit

left side
recieves oxyge-rich blood from lungs
pumps to body tissues
drop off O2, pick u CO2

Flow of blood through the body

areties, arterioles, capillaries, venules, veins

oxygenated/ deoxygenated blood in systemic

veins are deoxygenated, arteries are oxygenated

oxygenated and deoxygenated blood in the pulmonary

veins are oxygenated and arteries are deoxygenated

what does parallel flow mean

blood flows through one artery to capillaries of only one organ before returning to the heart via the veins

pericardium

membraneous sac that protects and anchors the heart, reduces friction for pumping heart

epicardium

visceral layer of pericardium

myocardium

cardiac muscle that contracts to pumping blood

describe the chambers of the heart

2 atria: recieving chambers, recieve blood from the veins
2 ventricles: pumping chambers, push blood into arteries

why is the left side thicker of the myocardial wall

because the it has to generate a stronger pump into the systemic which is longer and against gravity

arteries

carry blood away from the heart

capillaries

site of gas, nurtient, and waste exchange

veins

carry blood to the heart

veins leading blood into right atrium

superior vena cava, inferior vena cava

veins leading into left atrium

pulmonary veins

artery leading away from right ventricle

pulmonary trunk

artery leading away from left ventricle

aorta

av valves

tricuspid and mitral, one way inlets from atria into ventricles

sl valves

pulmonary and aortic, one way outlets from ventricles into major arteries

typical heartbeat consists of what

atrial contraction, relax, ventricular contraction, relax

heart sounds are caused by blood pushing valves open or closed

closed

lub sound

av valve closing

dub sound

sl valves closing

open av valves

heart is relaxed, atria contaact, pushing remaining blood into ventricles

closed av valves

ventricles contract, forcing blood against back side of cusps, papillary muscles contract and chordae tendinae tighten to prevent backflow

open sl valves

ventricles contract, pressure rises in ventricles pushing blood up on sl valves

closed sl valves

venrticles relax, blood flows backward from arteries and fills the cusps forcing them closed

what direction does blood flow

from high to low pressure

incompetent valve

valve fails to close and blood backflows, mitral valve

valvuar stenoisis

valve narrows and restricts flow

what is the effect of heart valve disorders on the heart

heart has to work a lot harder, enlarges and weakens overtime

blood flow through the heart

1. right atrium
2. tricuspid valve
3. right ventricle
4. pulmonary valve
5. pulmonary trunk
6. pulmonary ateries
7. pulmonary capillaries
8. pulmonary veins
9. left atrium
10. bicuspid valve
11. left ventricle
12. aortic valve
13. aorta
14. systemic arteries
15. systemic capillaries
16. systemic veins
17. superior/ inferior vena cava and coronory sinus

intercalated discs

connect cardiac muscle tissue

gap junctions

allows for action potentials to spread to neighboring cardiac muscle fibers so heart can contract as a whole unit

autorhythmic fibers

source of electrical activity that causes the heartbeat

autorhythmic fibers function

pacemaker, forms a conduction system

conduction system

pathway that delivers action potentials through heart muscle, ensures pumping action

what acts as the natural pacemaker

sa node (autorhythimc fibers)

conduction system pathway

sa node, av node, av bundle, right and left branches, purkinje fibers

contractile fibers

contract in response to action potentials from autorhythmic fibers, produce force

depolarization

Na+ inflow

plateau phase

K+ outflow, Ca+2 inflow

repolarization

additional K+ outflow

initial repolarizing phase

Na+ channels close, K+ channels open (between depolarization and plateau phases)

refractory period

due to plateau phase, cardiac muscle contractions cannot summate and cannot produce tetanus (sustained contraction)

electrocardiogram

records electrical signals of heart

p wave

atrial depolarization

p r interval

av node delay

qrs complex

ventricular depolarization

s t segment

depolarized state of ventricle

t wave

ventricular repolarization

what do enlarged waves and lengethened intervals indicate

myocardial infarction

depolarization causes

systole (contraction)

repolarization causes

diastole (relaxation)

cardiac cycle

all of the events associated with one heartbeat

passive ventricular filling

both atria and ventricles are in diastole, venoud blood returning to the heart enters the atria and leaks through open av valves into ventricles

why are the sl valves closed during passive ventricular filling

the pressure in the ventricles is lower than the aorta/ pulmonary trunk

atrial contraction

systole, pushes remaining 20% of blood into ventricles

the end of atrial systole

end of ventricular diastole

isovolumetric ventricular contraction

ventricular systole causes increase in pressure in ventricles and pushes av valves shut (all four valves are shut)

ventricular ejection

when pressure in ventricles exceeds pressure in aorta and pulmonary trunk, sl valves are forced open

isovolumetric ventricular relaxation

ventricular relaxation causes pressure in ventricles to drop, blood in the aorta and pulmonary trunk flow backwards filling cusps causing sl valves to close (all four valves are closed), atria and ventricles both diastole

cardiac output

heart rate x stroke volume, amount of blood ejected from each ventricle per minute

preload (effect of stretching)

more the heart fills with blood the greater the force of contraction, greater stretch greater sv

contractility

strength of myocardial contraction, greater contraction greater sv

positive ionotropic agents (alter contractility)

increase contractility, increased Ca+2 levels, sympathetic nervous system, epi and norepi

negative ionotropic agents (affect contractility)

decrease contractility, parasympathetic nervous system, increased extracllular K+ levels, acidosis

afterload

pressure in aorta or pulmonary trunk must be exceeded before sl valves can open, decrease sv

effect of hypertension

increase afterload, decreases sv and co

cardiovascular center

medulla oblongata

cardiovascular center recieves input from

higher brain centers, proprioceptors, chemoreceptors, baroreceptors

cardiovascular center sends output via

sympathetic neurons (cardiac accelerator nerve, increase hr and sv), parasympathetic neurons (vagus nerve, decrease hr)

types of blood vessels

arteries, arterioles, capillaries, venules, veins

smooth muscle

regulate blood vessel diameter via vasoconstriction and vasodilation, controlled by sympathetic divison of the ans

connective tissue

elastic, allows blood vessels to stretch

elastic arteries

pressure reservoirs

pressure wave

allows blood to continue flowing through arteries even when ventricles are relaxing

arterioles

deliver blood to capillaries, resistance vessels

continuous capillaries

most abundant, permeable to water, and small solutes

intercellular clefts

gaps between endothelial cells of capillary wall

fenestrated capillaries

have pores in their walls, higher permeability than continuous

sinusoids

large pores, most permeable including proteins and cells

why is venous blood return to the heart aided

low pressure graadient, sometimes working against gravity

blood reservoir

systemic venules and veins

lipid soluble

o2, vo2, steroid hormones

small water soluble

na+, glucose, amino acids

blood hydrostatic presure

promotes filtration, blood pressure result of heart pumping, due to blood hitting inner wall of capilary

interstitial fluid osmotic pressure

promotes filtration, due to the presence of solutes and proteins in IF (low)

blood colloid osmotic pressure

promotes reabsorption, due to the presence of plasma proteins in blood

interstitial fluid hydrostatic pressure

promotes reabsorption, due to if pushing on outside wall of capillary

net filtration

NFP = (BHP-IFOP) - (BCOP - IFHP)
filtration - reabsorption

net filtration occurs where

at the arterial end of a capillary

net reabsorption occurs where

at the venous end of a capillary

lymphatic system does what

picks up excess fluid filtered by the capillaries

functions of the lyphatic system

drains if, returns filtered plasma proteins back to the blood, carries out immune response, transports dietary lipids from gi tract via lacteals

shock

failure of cv system to meet metabolic demands of body cells

four types of shock

Hypovolemic, Cardiogenic, Obstructive, & Distributive

lymphatic vessels

greater permeability and larger diameter allow them to pick up larger substances (proteins, fats, microbes)

what happens at a lymph node

lymph is filtered of forign substances