Lecture 3 Flashcards
ECG
- PQ segment:
- PR interval:
- QT interval:
- ST segment:
- atrial systole (also represents the time it takes for signals to travel between SA and AV node)
- signal conduction through AV node, before activating ventricles
- duration of ventricular depolarization; shorter during exercise
- ventricular systole; also corresponds to plateau in myocardial action potential
Two main variables govern fluid movement:
1. ________ causes flow
2. _________ opposes flow
- pressure
- resistance
Fluid will only flow if there is a pressure gradient
- fluid flows from ______ pressure point to _____ pressure point
- high; low
Events occurring on left side of heart
- When ventricle relaxes and expands, its internal pressure ________
- If _______ valve is open, blood flows into left ventricle
- When ventricle contracts, internal pressure _____
- AV valves close (____), the _______ valve is pushed open and blood flows into aorta from left ventricle
- falls
- Mitral (av)
- rises
- S1; aortic (SLV)
Opening and closing of valves are governed by these _________ changes
- AV valves ______ when ventricles relaxes (lower pressure)
- semilunar valves under pressure from blood in vessels are ________ when ventricles are relaxed
pressure
- open
- closed
Valvular Insufficiency Disorders
1. _____________
2. ____________
- Incompetence
- Valvular stenosis
Incompetence
- any failure of a valve to prevent _______ (____________)
- valve should be _______, but isn’t
-often presents as a _______ ________: abnormal heart sound produced by regurgitation of blood through incompetent valves
- _______________: most common cause
- reflux (regurgitation)
- closed
- heart murmur
- calcification
Valvular stenosis
- cusps are __________ and _________ is constricted by scar tissue
- valve should be __________, but isn’t; might be partially ________
- caused by infection (______ ________); ____________ attack on the valves; _____ _______ forms
- stiffened; opening
- opened; open
- rheumatic fever; autoimmune; scar tissue
______________ listening to sounds made by body
- First heat sound (____), louder and longer “_____”, occurs when _____ valves close, turbulence as blood hits closed valve, movements of the heart wall
- Second heart sound (____) softer and sharper “_____”, occurs when ___________ valves close, turbulence as blood hits closed valve, and movements of the heart wall
-____ & _____: need amplification to hear them
- _______: rapid ventricular filling
- _______: ventricular filling during atrial systole
auscultation
- S1; lubb; AV
- S2; dupp; semilunar
-S3 & S4
- S3
- S4
Phases of the Cardiac Cycle
1.
2.
3.
4.
- The entire cardiac cycle (all four of these phases) is completed in less than ____ _________
- Ventricular filling (during diastole)
- Isovolumetric contraction (during systole)
- Ventricular ejection (during systole)
- Isovolumetric relaxation (during diastole)
- 1 second
Ventricular filling (during diastole)
- atrial pressure ____ ventricular pressure
- arterial pressure ___ ventricular pressure
- AV valves ________
- Semilunar valves _____
- EKG: _____________
- >
- >
- open
- closed
- p wave
Isovolumetric contraction (during systole)
- atrial pressure ____ ventricular pressure
- arterial pressure ___ ventricular pressure
- AV valves ________
- Semilunar valves _____
- EKG: _____________
- <
- >
- closed (S1)
- closed
- QRS complex
Ventricular ejection (during systole)
- atrial pressure ____ ventricular pressure
- arterial pressure ___ ventricular pressure
- AV valves ________
- Semilunar valves _____
- EKG: _____________
- <
- <
- closed
- open
- QRS complex
Isovolumetric relaxation (during diastole)
- atrial pressure ____ ventricular pressure
- arterial pressure ___ ventricular pressure
- AV valves ________
- Semilunar valves _____
- EKG: _____________
- <
- >
- closed
- closed (S2)
- t wave
- End-diastolic volume= ______ mL
- End- systolic volume= ______ mL
- SV= _____ mL
- 130
- 60
- 70
Overview of Volume changes
- ESV= 60 mL
- Passively added to ventricle during atrial diastole=
- Added by atrial systole=
- Total: EDV= 130 mL
-SV ejected by ventricular systole=
- left behind: ESV= 60 ML
Both ventricles _______ eject _____ amount of blood
- (+30 mL)
- (+40 mL)
- (-70 mL)
MUST; SAME
At Rest!!
_____ mL per beat * ____ beats per minute= _____ L per minute
- the flow rate (volume/min) is _______ _______
- average person has ____-____L blood
70 mL * 75 bpm= 5 L/min
- cardiac output
- 4 to 6
A blood cell leaving the left ventricle takes about a _________ to make its way through the circulation and back to the left ventricle!
minute
CO= ______ * _______
How is this regulated?
- _______________
- _______________
HR * SV
- autonomic nervous system
- exercise/ fitness
Heart rhythm and contraction are controlled by two cardiac centers in the ___________ __________
1.
2.
- Autonomic nervous system DOES NOT initiate the heartbeat, it modulates _________ and _______
medulla oblongata
1. cardioacceleratory center
2. cardioinhibitory center
- rhythm; force
Cardioacceleratory center
- sends _________ innervation via the _______ nerves
Cardioinhibitory center
- sends ________ innervation via the _______ nerve
- sympathetic; cardiac
- parasympathetic; vagus
Sympathetic nerves _________ heart rate and _______ __________
- originates in ______ ______
- sympathetic chain ganglia
- postganglionic fibers pass through ______ _______ in mediastinum and continue as _________ nerves to the heart
- fibers terminate in ____ and ____ _________ (also _______, _______________, and _______________)
INCREASE; contraction strength
- spinal cord
- cardiac plexus; cardiac
- SA and AV nodes (aorta, pulmonary trunk, coronary arteries)
Parasympathetic nerves _______ heart rate ONLY
- vagus nucleus in the __________ _________
- fibers to _______ ______ and continue to the heart by way of _______ nerves
- Fibers of ______ vagus nerve lead to ____ node
- Fibers of ______ vagus nerve lead to ____ node
- little or no vagal stimulation of the ___________
SLOW
- medulla oblongata
- cardiac plexus; cardiac
- right; SA
- left; AV
- myocardium
_____________: resting adult HR above _____ bpm
caused by
- _______, anxiety, ________, heart disease, or ______
- _______ of blood or ________ to myocardium
(your body wants to compensate for the loss of blood)
Tachycardia; 100
- stress; drugs; fever
- loss; damage
Positive chronotropic agents: factors that _____ HR
- Sympathetic ANS–> releases _____
- binds to __-_________ fibers in the heart
- _______ accelerates depolarization of SA node
- By accelerating both _________ and _________, increases HR as high as ______ bpm
increase
- NE
- Beta-adrenergic
- Ca2+
- contraction; relaxation; 230
____________: resting adult HR of less than ____ bpm
Bradycardia; 60
Negative chronotropic effects: factors the ______ HR
- _________: holds down the heart rate to 70-80 bpm at rest
- steady background firing rate of the _____ nerves
- In ______, low body ______, and _________-_______ ____________
- Parasympathetic vagus nerves have cholinergic inhibitory effects on _____ and _____ ________
- ______ binds to muscarinic receptors, opens _____ channels
- _____ leaves nodal cells, they become ____________ and fire less frequently—> ________ HR
decrease
- vagal tone
- vagus
- sleep; temperature; endurance- trained athletes
- SA and AV nodes
- ACh; K+
- K+; hyperpolarized; decreased
Chronotropic Effects of the ANS and CNS (portions of somatic nervous system)
- ________ to cardiac centers in medulla are diverse
- _________ __________ ______ (cerebral cortex, limbic system, hypothalamus)
- sensory or emotional stimuli
- muscles, joints, arteries, and brainstem
-_________________ in muscles and joints inform cardiac centers about changes in activity, so HR increases before metabolic demands on muscle arise
- inputs
- higher brain centers
- proprioceptors
How does the ANS know what’s going on?
- sensory inputs to cardiac centers
1. ____________: blood pressure sensors
2. ____________: senses blood pH, CO2, and O2 levels
- Baroreceptors
- Chemoreceptors
Baroreceptors
- If BP decreases , signal rate ______, cardiac center ___________ HR
- If BP increases, signal rate _____, cardiac center _______ HR
- drops; increase
- rises; decrease
Chemoreceptors
- high blood CO2 (_________) leads to ________ and ________ HR
- low O2 in blood (________) _______ HR
- hypercapnia; acidosis; increases
- hypoxemia; decreases (your body will shut down other activities in the body that need oxygen, since we don’t have enough of it—> we don’t need blood to be pumped out that fast)
