BIO365S Exam 3 (Cheng UT Austin)

How many chambers in the heart?

4

Which cell type will experience a plateau on during action potential?

the contractile cell will experience a Ca+ plateau due to influx

Does the contractile cell or the auto-rhythmic cell have a longer refractory period?

the contractile cell will have a longer refractory period (anywhere between 0-200milliseconds) due to a plateau to avoid a muscle cramp

What electrical events does ECG look at?

depolarization and repolarization

P Wave (ECG)

atrial depolarization in SA Node

QRS Complex (ECG)

ventricular depolarization in AV node

T Wave (ECG)

ventricular repolarization (relax)

PR Interval (ECG)

includes P wave and PR segment

PR Segment (ECG)

part of atrial contraction (after depolarization)

ST Segment (ECG)

part of ventricular contraction and atrial relaxation

QT Interval (ECG)

QRS Complex wave and ST segment

Do intervals include waves? (ECG)

Yes

Do segments include waves? (ECG)

No

Which type of wave follows the QRS Complex?

T Wave

Which wave, segment, or interval would you analyze to determine:

AV node delay

PR segment

Which wave, segment, or interval would you analyze to determine:

Atrial rhythm

P-Waves (or P-P interval)

Which wave, segment, or interval would you analyze to determine:

Conduction through ventricular muscle

QRS Complex

Which wave, segment, or interval would you analyze to determine:

Refractory period of contractile AP

ST or QT intervals

What happens to sodium when the membrane potential of a contractile cell increases?

Na+ moves into the cell

What happens to sodium when the membrane potential of a contractile cell is at resting potential (stage 4)?

Na+ channels open

What is the phase called when membrane potential increases and Na+ channels open?

rapid depolarization -- it's becoming more positive

What happens when Na+ channels close during contractile cell in regards to membrane potential?

K+ channels open

What is the phase called when membrane potential hits a certain level and K+ channels open during contractile cell action potential?

rapid repolarization

What happens to the channels during phase 2 (plateu) in contractile cell action potential?

K+ channels close; Ca+ channels open, allowing Ca+ to move into the cell

What is the phase after the Ca+ channel closes in contractile cells action potential?

Phase 3; rapid repolarization

What are the two main types of cells in the heart?

Auto-Arrhythmic cell and contractile cell

Auto-Arrhythmic Cell

they can depolarize by themselves without any stimulation (pacemaker)

What type of cell is the heart conducting system composed of?

Auto-Arrythmic cells; they can continuously send out electrical signals which will stimulate the contractile cells

What is the conducting zone in the respiratory system?

the upper part that funnels the air into the body; comprised of nose, mouth, larynx, lungs, nasal cavity, trachea, and pharynx

Do lung cells need to remain wet or dry?

wet; in order for the gases to dissolve and diffuse across cell membranes

What is the nose's purpose?

to warm and moisten incoming air to avoid drying out the sensitive lung cells that need to remain wet

What are the two parts of the trachea?

left bronchus and right bronchus

What is the respiratory zone?

the lower part where the gas exchange occurs; comprised of bronchioles, alveolar ducts, and alveoli

What is at the end of bronchioles?

alveolar ducts leading to alveolar sacs

Hypocapnia

insufficient carbon dioxide

Molecules diffuse from areas of _______ concentration to areas of _______ concentration

high; low

More molecules in a certain volume means ________ air pressure

more

Dissolved gases always ________ _______ their partial pressure gradient

diffuse down

What triggers a skeletal muscle contraction?

release of Ca+ binding to troponin (exposing the active binding sites on actin)

Do lungs move on their own during inhalation?

No, the diaphragm contracts and moves down, allowing the lungs to fill with outside air

Do lungs move on their own during exhalation?

No, the diaphragm relaxes and expands up, pushing the air out of the lungs

What are the four chambers of the heart?

right atrium, left atrium, right ventricle, left ventricle

What type of chambers are the atria?

receiving chambers for the blood coming back to the heart after circulating through the body

What type of chambers are the ventricles?

discharging chambers that push the blood out

Do atria have thick or thin walls?

Thin because they are the low pressure chambers, so thick walls are not necessary

Do ventricles have thick or thin walls?

Thick because they are the "true pumps of the heart" and need thick walls to be able to shoot the blood back out of the heart

Arteries carry blood _____ the heart

from

Veins carry blood _____ the heart

toward

Contractile cells of the heart are different from pacemaker cells in that contractile cells....

have a calcium plateau and a long refractory period

What factor has a negative (inverse) relationship with resistance?

Radius of the vessel

The _____________ is the same in all of the body vessels, but the ____________is different, due to the difference in the _____________ of the vessels.

Blood flow, blood velocity, cross-sectional area

Blood flows in the cardiovascular system . . .

Down a pressure gradient from capillaries to vena cavae, Down a pressure gradient from arterioles to veins, Due to the contraction of the heart

Select the correct statement regarding EC-coupling in skeletal muscle:

a.) Signal comes from the motor neuron which releases norepinephrine into the neuromuscular junction.

b.) End plate potential (EPP) is a graded potential that is not good at traveling long distances. This is why T-tubules are needed.

c.) DHP receptors is a mechanically gated receptor that is attached to the sarcoplasmic reticulum

d.) When the calcium is released from the sarcoplasmic reticulum, it attaches to tropomyosin which causes troponin to pull away from the actin binding sites.

B: End plate potential (EPP) is a graded potential that is not good at traveling long distances. This is why T-tubules are needed.

Choose the correct statement about a cardiac contractile cell action potential:

a.) The calcium plateau is ~350 msec long, which allows the muscle to relax before firing.

b.) The calcium plateau is around 250-300 msec long, which allows the muscle to keep firing within this time frame.

c.) During the calcium plateau both Ca2+ and fast K+ channels open.

d.) During the calcium plateau Ca2+ channels open and fast K+ channels close.

D: During the calcium plateau Ca2+ channels open and fast K+ channels close.

Which are true regarding EKGs?

a.) The mechanical events (contractions or relaxations) lag slightly behind the electrical events (shown as waves on the EKG)

b.) The EKG begins with atrial depolarization

c.) The QRS complex is sometimes absent on normal EKGs

d.) The AV node delay occurs during the P-R segment

CORRECT:

a.) The mechanical events (contractions or relaxations) lag slightly behind the electrical events (shown as waves on the EKG)

b.) The EKG begins with atrial depolarization

c.) The AV node delay occurs during the P-R segment

Select the false statement:

a.) Autorhythmic cells (also called pacemakers) set the heartbeat rate

b.) Autorhythmic cells contribute to the contractile force of the heart

c.) Most cardiac muscle is contractile

d.) The heart can contract without being connected to other parts of the body

e.) More than one above is false

B is false: Autorhythmic cells contribute to the contractile force of the heart

The _____________ modulate(s) heart rate, but the signal comes from the ______________ cells.

ANS, pacemaker

The influx of calcium in myocardial contractile cells plays a role in:

a.) Creating the plateau seen in contractile cell action potentials

b.) Opening RyR channels in the sarcoplasmic reticulum

c.) Myocardial relaxation

d.) More than 1 above correct

D: More than 1 above correct

Which pressure is lowest during ventricular systole?

Atrial

Heart sound 2:

a.) is generated by the closing of the atrioventricular valves

b.) occurs when the aortic and pulmonary valves backfill with blood

c.) marks the end of isovolumic relaxation

d.) is associated with turbulence during atrial contraction

e.) is louder than heart sound 3

B: occurs when the aortic and pulmonary valves backfill with blood

Choose the false statement about stroke volume:

a.) Is the amount of blood pumped by one ventricle during a contraction

b.) Can be calculated by EDV-ESV

c.) Is always constant by homeostasis

d.) Decreases when afterload increases

e.) No false answer

C is false: Is always constant by homeostasis

Choose the correct statement about the mechanical events of the heart:

a.) The mean arterial pressure is calculated (systolic + 2* diastolic)/3 which counts for fact that the heart spends more time in the systolic phase than the diastolic

b.) There is a period where the atria and the ventricles contract at the same time

c.) Most of the ventricle fills up via active filling

d.) During the ventricle systole, both of the AV valves shut close at the same time

e.) More than one above is correct

D: During the ventricle systole, both of the AV valves shut close at the same time

Cardiac output is affected by... (choose as many as apply)

a.) Heart rate

b.) Contractility

c.) Respiratory pump

d.) Venous constriction

e.) all of the above

e.) all of the above

Cardio output decreases when:

a.) Preload increases

b.) You Answered Afterload increases

c.) Increase in intracellular calcium concentration

d.) decreasing heart rate

e.) More than one above is correct

E: More than one above is correct (a and d)

Baroreceptors ________________ their firing rate in response to an increase in blood pressure, activating the CVCC, which increases ______________ activity and decreases _____________ activity to slow down the heart and dilate the arterioles.

Increase, parasympathetic, sympathetic

Choose the false statement(s) about the baroreceptor reflex:

a.) Baroreceptors are stretch receptors

b.) An increase in blood pressure decreases the firing rate

c.) The baroreceptor reflex provides a rapid response

d.) Is an all or none response

B: An increase in blood pressure decreases the firing rate and D: Is an all or none response ARE FALSE

Blood pressure would decrease by:

vasolidation

Vasolidation

The enlargement of blood vessels to increase blood supply; widening of blood vessels

Choose the correct statement about preload and afterload:

a.) Preload is the ventricular pressure at the end of systole

b.) Afterload is the EDV at the beginning of systole

c.) A high afterload can result from high blood pressure

d.) A high preload during exercise is typically unhealthy

e.) An increase in afterload will increase cardiac output

C: A high afterload can result from high blood pressure

On which atrium is the vena cava located?

Right atrium

Valves are designed to parachute easily open for blood flow. Are valves able to flip directions easily?

No, they are designed to keep the blood flowing in one direction

Flow of blood:

right side of heart --> lungs --> left side of heart

The right side of your heart receives oxygen-poor blood from your veins and pumps it to your lungs, where it picks up oxygen and gets rid of carbon dioxide. The left side of your heart receives oxygen-rich blood from your lungs and pumps it through your arteries to the rest of your body.

Which is smaller: the right pump or the left pump?

the right pump is smaller, the left pump is larger

What do tissues produce with oxygen?

oxygen to produce oxygenated blood to eventually circulate back to the vena cava on the right side

What does Professor Cheng refer to the cardiac muscles as?

Advanced muscles, they have the advantage of skeletal muscle without the shortcomings of skeletal muscle

Which muscle is stronger: skeletal or cardiac?

Cardiac muscle; they are structurally similar to skeletal muscle, without the weakness of skeletal muscles.

Can cardiac muscles "cramp"?

No, they do not have the shortcoming of skeletal muscles

Can skeletal muscles "cramp"?

Yes, for example, after extended periods of movement or exercise

What is a heart attack in terms of blood flow?

Blockage of the coronary artery where blood cannot fully flow to the heart

Which of the following ECG interpretations is correct?

a.) The amplitude of the ECG is related to the body weight.

b.) The P wave corresponds to atrial relaxation

c.) The P wave corresponds to ventricular depolarization

d.) The QRS complex corresponds to ventricular repolarization

e.) The T wave corresponds to ventricular repolarization

e.) The T wave corresponds to ventricular repolarization

Choose the correct statement about the pacemaker cells in the electrical conducting system of the heart.

a.) The electrical signal goes in the direction: SA => bundle of branch => AV => internodal pathway => Purkinje fibers

b.) The firing rates of SA node > AV node

c.) All pacemaker cells receives both sympathetic and parasympathetic innervations.

d.) All pacemaker cells have the same firing rate.

e.) More than 1 above correct.

b.) The firing rates of SA node > AV node

Choose the correct statement of the afterload:

a.) It is the end diastolic volume.

b.) It is the end systolic volume.

c.) When the afterload increases, stroke volume increases.

d.) When diastolic pressure increases, afterload increases.

e.) More than 1 above correct.

d.) When diastolic pressure increases, afterload increases.

In the Wiggers diagram,

a.) Atrial pressure varies between around 20mmHg and 120mmHg.

b.) Ventricular contraction occurs immediately after the T wave.

c.) Atrial contraction happens immediately after the P wave.

d.) Blood ejection to aorta happens immediately after the P wave.

c.) Atrial contraction happens immediately after the P wave.

Bill's systolic pressure = 121mmHg, and pulse pressure = 30mmHg. Choose the correct answer:

a.) His MAP = 111mmHg.

b.) His MAP = 91mmHg.

c.) His diastolic pressure is 101mmHg.

d.) His diastolic pressure is 91mmHg.

e.) More than 1 above correct.

d.) His diastolic pressure is 91mmHg.

Choose the correct statement about the body's response about the blood pressure change after a person drank 1L of water:

a.) Blood pressure never changes due to the local control of blood pressure.

b.) Both CVCC and kidneys as the integration centers are activated.

c.) Systemic vasoconstriction is a response.

d.) Baro-receptor firing rates decrease.

e.) More than 1 above correct.

b.) Both CVCC and kidneys as the integration centers are activated.

Choose the correct statement about the respiratory pump:

a.) Lung serves as the main pump in the respiratory system.

b.) Rectus abdominus is the main muscle used for inspiration.

c.) Contract the diaphragm decreases the thoracic cage volume.

d.) None above correct.

d.) None above correct.

Select the correct statement regarding transpulmonary pressure (TPP):

a.) TPP is the intrapleural pressure.

b.) When the TPP is higher than zero, the patient is in danger of pneumothorax.

c.) The TPP at the end of inspiration and expiration is equal to the intrapleural pressure.

d.) The TPP of a healthy person always ranges from 3 to 6 mmHg.

e.) More than 1 above correct.

d.) The TPP of a healthy person always ranges from 3 to 6 mmHg.

Is a sarcomere thick or thin filaments?

Both, the entire unit

What are thick filaments in a sarcomere made of?

Myosin

What are thin filaments in a sarcomere made of?

Actin

Do we only have thick and thin filaments? Why or why not?

If you only have thin and thick filaments (myosin and actin), your muscles would constantly be contracting, which is why we need the TROPOMYOSIN to block the binding site of ACTIN

What initiates the contraction in skeletal muscle?

a calcium signal

In excitation-contraction coupling and relaxing, what does removing calcium do?

Relaxes

True or false: contractility in the heart is graded

True

What is the force of contraction proportional to?

the concentration of ICF calcium

Where do signals come from in electrical conduction within the heart?

Signals come from heart itself

Where does modulation come from in the electrical conduction within the heart?

modulation comes from parasympathetic nervous system

Auto-rhythmic cells have unstable membrane potentials called .....

pacemaker potentials

The pacemaker potential gradually becomes less negative until it reaches threshold, triggering an....

action potential

How long does the contraction of a cell take?

250-300 milliseconds