CH 13 HEART

(0) resting membrane potential

-70mV, created by efflux of K+, small amount of CA, Na+

The events of the cardiac myocyte action potential include:

1. Inward rectifier potassium channels are open¸ creating high potassium permeability. 2. Depolarization from resting membrane potential occurs. 3. Fast sodium channels increase sodium permeability. 4. Refractory period begins. 5. Calcium permeability increases. 6. Delayed rectifier potassium channels open. 7. L-type calcium channels close.

What is the mean arterial pressure (in mmHg) in that same person discussed previously? Systolic blood pressure is 180 mmHg and diastolic blood pressure is 90 mmHg.

120

You are measuring a person's blood pressure following a brief bout of exercise. Their systolic blood pressure is 180 mmHg and the diastolic blood pressure is 90 mm Hg. What is their pulse pressure in mmHg?

90

The ___________ creates a short delay in conduction and is capable of firing 40-60 action potentials per second.

AV node

Match each capillary type to a location in which it is found. Sinusoid

Bone marrow

(3) Plateu phase

Ca channels open, bring (+) charge Ca ions to cell, two pop electrical forces create plateu

Why are contractile myocytes different than pacemaker cells?

Contractile cells are more abundant than pacemakers.

Match each of the following to its described impact on blood pressure. Decreased HR

Decreased BP due to decreased CO

Match each of the following to its described impact on blood pressure. Increased BV diameter

Decreased BP due to decreased R

T/F the QRS Complex corresponds to ventricular depolarization

False

Features of the pericardium

Fibrous pericardium, serous pericardium

Match each of the following to its described impact on blood pressure. Increased SV

Increased BP due to increased CO

(4) Rapid Repolarization

L- type Ca channels cellulose, efflux of K continues, mem pont repolarizes to resting state

Assume that the following are the hydrostatic and osmotic conditions at the venous end of a capillary bed: CHP = 17 mmHg, IFHP = 0 mmHg, BCOP = 26 mmHg, IFCOP = 12 mmHg. Based on these conditions, which statement below correctly describes NFP and the direction of fluid movement?

NFP is 3 mmHg; filtration is occurring.

(2) Transient Repolarization

Na channels inactivate at peak, Na perm dec. , Cardiomyocytes go into a refractory period, Mem potn starts to hyper polarize

What phase of the ECG corresponds with atrial depolarization?

P wave

Cardiac anastomoses ______.

Provide alternate paths for blood flow

which region of the electrocardiogram displays the time course required for ventricular depolarization and repolarization

Q-T Interval

While preparing her patient for an ECG, a cardiologist accidentally switches the position of the positive and negative electrodes. What will be the impact, if any, on her recording?

Repolarizing current will give a positive deflection.

which phase of cardiac Action Potential is primarily mediated through inward rectifier K channels ?

Resting Membrane Potential

The ______________ also known as the "pacemaker" and is capable of firing approximately 100 action potentials per second.

SA Node

order of the cardiac excitation sequence

SA node, internodal pathway, AV node, Bundle of HIS, R & L Bundle branches, purkinje fibers

Match each capillary type to a location in which it is found. Continuos

Skin

Match each capillary type to a location in which it is found. Fenestrated

Small intestine

A pathological accumulation of fluid in the pericardium is called cardiac tamponade.

True

T/F the pulmonary & systemic system are connected & highly connected, contract & relax together, pump roughly the same vol of blood

True

Cardiac output

amount of blood pumped by a ventricle in a period of time

sequence of red blood cel leaving left ventricle

aorta, vena cava, right atrium, right ventricle

Anatomically, the inferior portion of the heart is also known as the ______.

apex

Like skeletal muscle, cardiac muscle cells ______.

are striated

These arteries can be so small that their wall is only an endothelium and a thin layer of smooth muscle fibers

arterioles

Which arteries are most directly responsible for controlling the amount of blood entering individual capillary beds?

arterioles

P-R interval

atrial depolarization to propagate through the ventricles

The ____________________ conducts action potentials through the interventricular septum

bundle of HIS

Which vessel types may be porous enough to allow diapedesis? Select all that apply.

capillaries, venues, Capillaries are the most permeable type of blood vessel. Postcapillary venules have walls that are thin enough to allow diapedesis.

One difference between cardiac and skeletal muscle is that ______.

cardiac myocytes have a single nucleus

Which of the following effects would cause decreased venous return?

decreased breathing rate

contraction of heart

decreases chamber volume, increases chamber pressure

Endocardium

deepest layer, squamous endothelial tissue

The right side of the heart pumps ______ blood through the ______ circulation.

deoxygenated; pulmonary

S wave

depolarization of Inferior portions of ventricle

R wave

depolarization of anterior region of ventricle

P wave

depolarization of atria

Q wave

depolarization of septal region of ventricle

cardiac reserve

difference between resting and maximal CO

Peripheral resistance is ______. Select all that apply.

directly proportional to blood viscosity & vessel length

These arteries are closest to the heart and have relatively larger lumens than other arteries

elastic arteries

What does an ECG measure?

electrical activity of the heart

EKG waves correlate with discrete _____ _______ in the heart

electrical changes

ECG provide ____ ____ of heart function

electrical picture

Place the following in the order that they would be encountered as you move from the inside of a heart chamber toward the thoracic cavity:

endothelial cell layer, cardiac skeleton, epicardium, pericardial fluid, parietal pericardium, fibrous pericardium

What is the name of the vessels that take blood to alternate routes in the fetus?

fetal shunts

Key fact of fluid dynamics

flow, pressure, Boyles, law, resistance, pressure gradient, valves

CO

heart rate x stroke volume

Blood flows from regions of ______ pressure to regions of ______ pressure.

high, low

Suppose that production of blood plasma proteins by the liver is significantly decreased. Will this directly cause an increase or a decrease in the net filtration pressure (NFP) in capillaries?

increase

Will the release of nitric oxide from the endothelial cells of an arteriole increase or decrease in response to a decreased pH of the tissue it serves?

increase

Relaxation

increased chamber volume, decreases chamber pressure

phosphorylation of PKA _______ the strength of cardiac contraction

increases

Which feature of the capillary wall results from incomplete tight junctions?

intercellular clefts

During this phase of the cardiac cycle, pressure inside the right ventricle increases until it becomes equal to the pressure inside the pulmonary artery.

isovolumetric contraction

Rupture of the chordae tendinae sometimes occurs in patients with endocarditis (inflammation of the endocardium). This disorder would most likely require surgery on which of the following valves?

mitral valve

These arteries have the thicker tunica media of any vessel type

muscular arteries

An artery with a relatively thick tunica media and a total diameter between 0.1 cm and 1 cm is most likely to be which type?

muscular artery

Pacemaker cells are located in the ______; contractile cells are located in the ______.

myocardium; myocardium

valves create _____directional blood flow

one

Which of the following is essential for one-way blood flow through veins?

one-way valves found with veins

epicardium

outermost layer, loose connective & adipose tissue

Electrical coordination of the atria and ventricles is due to ______.

pacemaker cells in the atria being in the refractory period while ventricles are depolarizing

pulmonary & systemic system pumps work In _______

parallel

serous pericardium

parietal layer (outermost) and visceral layer , continuous with heart

Boyles law

pressure and force inverse relationship

venous valves

prevent back flow

The primary function of the papillary muscles is to ______.

prevent the eversion of the tricuspid valve

two divisions of circulatory system

pulmonary and systemic circuits

The ____________ have a rapid conduction velocity due to many gap junctions and conducts electrical signals directly to contractile myocytes in the ventricle.

purkinje fibers

Which of the following contains blood w the lowest O2 content

right ventricle,

What will be the result if the blood continues to back up?

right-sided hear failure

Arrange the capillary types in order from most to least permeable.

sinusoid, fenestrated, continuous

Extrinsic Regulation OF cardiac Output

sympathetic & parasympathetic affects

Which of the following pumps oxygenated blood

systemic pump

Einthoven's triangle

the triangle around the heart formed by the bipolar limb leads

what doe the following structures have in common inferior vena cave, superior vena cave, coronary vein, & pulmonary artery

they all carry deoxygenated blood

cardiac muscle and skeletal muscles are similar in that

they both use the sliding filament model for contraction

Myocardium

thick middle layer with cardiomyocyes & cardio skeleton

chordae tendineae

thin bands of fibrous tissue that attach to the tri & bicuspid valves in the heart and prevent them from inverting

The heart is located in the ________ cavity, protected by the ___________

thoracic, pericardium

P-Q interval

time req for atrial depolatizaition and AP to reach ventricles

the P to R interval in an electrocardiogram represents _____

time required for cardiac action potential to propagate through the ventricles

fibrous pericardium

tough, white fibrous connective tissue that is the outer layer of the pericardium

Which component of the cardiovascular center can influence blood pressure by varying the total peripheral resistance?

vasomotor

QRS complex

ventricular depolarization and atrial repolarization

T Wave

ventricular repolarization

(1) Depolarization

voltage-gates Na channels activated

Look closely at Poiseuille's equation. If the viscosity (thickness) of a fluid moving through a tube were to decrease, what would happen to the value of ΔP?

ΔP would decrease.