Chapter 11 Cardiovascular System, The Heart Part 2 Flashcards

1
Q

Where will blood flow immediately after the right ventricle?

A. Right atria
B. Left atria
C. Aorta
D. Right ventricle

This blood is oxygen-___________.
A. rich
B. poor

A

B. Left Atria

A. Rich

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

During changes of membrane potentials of SA node cells, what is occurring before threshold?

A. Potassium is leaking into the cells
B. A mechanical stimulus is causing a local potential
C. An action potential is initiated
D. Calcium is leaking into the cells
E. Sodium is leaking to the cells

A

D. Calcium is leaking into the cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What are the concepts of quantity/volume and pressure?

A
  • For a fixed volume of fluid, pressure depends on the volume of the space it occupies
    • Large space = lower pressure
    • Small space = high pressure
    • As the size of the space changes, so does the pressure
    • Think of heart chambers as the space containing a fluid
  • Pressure gradient
    • Differences in pressure between two pointsLike diffusion, substances flow from high pressure to low pressure
    • As the substances flows, pressure at the first point will decrease and pressure and the second point will increase
    • This is true, as long as the path is not blocked (THINK valves!)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What happens to the volume of chambers and what must we consider?

A
  • Volume of chambers change during a heartbeat
  • We must also consider pressure in vessels
    • Elastic nature of vessels exert pressure on blood inside
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What is relaxation, contraction, and the cardiac cycle?

A
  • Relaxation  Diastole
    • Space of the chamber increases
    • What happens to pressure? A – Increase, B - Decrease
  • Contraction  Systole
    • Space of the chamber decreases
    • What happens to pressure?
  • The Cardiac Cycle
    • One complete contraction and relaxation
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What happens in the Quiescent Period or Phase 1?

A
  • Nothing is going on with the anatomy
  • Anatomy - the atria and ventricles are relaxed
  • Conduction - SA node cells are depolarizing (via leak cation channels)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What happens during the atrial systole or Phase 2?

A

Anatomy - Atrial contraction, ventribles are relaxed

Conduction - SA node action potential

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What happens during the ISOvolumentric Contraction or Phase 3?

A

Anatomy - Atria relax ventricles contract

Conduction - AV node deploarization (bundle of HIS) and Purkinge Fibers

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What happens during the Ventricular Ejection (phase 4)?

A

Anatoomy - ventricles are fully contracted

Conduction - AV nodes are depolarizing (Bundle of HIS) and purkinje fibers

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What happens in Isovolumetric relaxation (Phase 5)?

A

Anatomy - atria relaxed, ventricles begin to relax

Conduction - repolarization of AVnode, Bundle of HIS, Purkinje

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Which part of the conduction system is responsible for atrial systole?

A. Purkinje fibers
B. SA node
C. AV node
D. Bundle of His

A

B. SA node

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Which part of the conduction system is responsible for maximum ventricle contraction?

A. Purkinje fibers
B. SA node
C. AV node
D. Bundle of His

A

A. Purkinje fibers

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

How do you get stroke volume?

A

End Diastolic Volume (EDV) – End Systolic Volume (ESV) =
Stroke Volume

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q
A
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What is Cardiac Output and how do you get it?

A

  • Cardiac output (CO) is the amount of blood pumped by the left ventricle in one minute
  • Heart rate (beats/minute) X Stroke volume (mL/beat)

–HR x SV = CO

•Example:

–75 beats/minutes x 70 mL/beat = 5,250 mL/minute or 5 liters

–Humans have 4-6 liters total blood volume

–On average, the total blood volume is pumped through the heart per minute

–This is resting cardiac output

–During exercise, CO can be as high as 35 L/minute

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What is the Cardioacceleratory center and what does it do to affect heart rate?

A
  • Cardioacceleratory center  Increase heart rate
    • Collection of cells in the medulla oblongata
  • What type of neurons - Visceral motor (Sends info to the Brain/Organ rellated)
  • Postganglionic neuron secretes norephinephrine (NE)
    • Adrenergic receptors on cells of the SA node bind NE
    • Cause an increase rate of ction potentials of SA node
  • Maximum heart rate is 230 beats/minute
    • Limit of SA node excitation
17
Q

What is the Cardioinhibitory center and what does it do to affect heart rate?

A
  • Cardioinhibitory center  Decrease heart rate
  • Visceral motor neurons of the parasympathetic system
  • Postganglionic neuron secretes acetylcholine (ACh)
    • Cholinergic receptors on cells of the SA node bind ACh
    • Allow potassium to leave the cell  hyperpolarizing reaction
    • Rate of action potentials decrease
  • Normal heart rate is 70 beats/minute
    • Without nervous control the heart would beat about 100 beats/minutes
18
Q

What effects stroke volume?

A
  • Preload and afterload
  • Preload  Frank-Starling law of the heart
    • Stroke volume is proportional to final ventricular volume
    • If more blood is forced into the ventricle (during exercise), the ventricle stretches more
    • Results in a greater contraction
  • Afterload  blood pressure in arteries
    • Higher blood pressure reduces the stroke volume
    • Hypertrophy of ventricles is indication of high blood pressure
19
Q

What information is integrated in deciding heart rate?

A
  • Sensory input
  • Proprioceptors
    • Inform brain of changes in physical activity
    • Increases heart rate before metabolic demand
  • Baroceptors
    • Sense pressure in vessels
    • Pressure to high, lower heart rate
    • Pressure to low, increase heart rate
  • Chemoreceptors
    • Sensitive to pH of blood
    • Important in respiratory system, but has some affect on heart rate
    • Too much carbon dioxide (waste), increase heart rate to remove
20
Q
A