Cardiovascular System

Question 1

What are the three interrelated components of the cardiovascular system?

Answer 1

The blood, the heart, and the blood vessels.

Heart pumps blood and blood vessels allow blood to circulate to all parts of the body.

Question 2

What is the major function of the cardiovascular system?

Answer 2

Transportation: Delivery of oxygen, nutrient molecules, and hormones, and removal of carbon dioxide, ammonia, and other metabolic wastes.

Question 3

Where are the points of exchange between the blood and surrounding tissues found?

Answer 3

In the capillaries.

Question 4

Where is the heart located?

Answer 4

In the thoracic cavity withing the mediastinum between the lungs

Question 5

What is the approximate size of the heart?

Answer 5

About the size of an adult fist.

Question 6

Where does the apex of the heart point?

Answer 6

Inferiorly toward the left hip.

Question 7

What are the two layers of the serous membrane around the heart called?

Answer 7

Parietal layer that lines the cavity and visceral layer that covers the organs in the cavity.

Question 8

Where is the fibrous pericardium found? What is it composed of and what are the 3 major functions of the fibrous pericardium?

Answer 8

Location: Outermost layer of the pericardial membranes

Composition: Tough dense connective tissue layer.

1] Protects heart
2] Anchors it to surrounding structures, such as the diaphragm and the great vessels that issue from the heart
3]It prevents overfilling the heart with blood

Question 9

Where is the pericardial cavity located, what does it contain and what is its function?

Answer 9

Located in the thoracic cavity, anterior to the liver.

Contains serous fluid (pericardial fluid).

Serous membranes, lubricated by the fluid, glide against one another during heart activity, allowing the mobile heart to work in a friction-free environment.

Question 10

What is the myocardium, and what is its function?

Answer 10

The myocardium is a layer of cardiac muscle tissue that contracts involuntarily when a ventricle (left or right) fills up with blood, to pump it towards the rest of the circuit.

Question 11

What are the two divisions of the circulatory system?

Answer 11

Pulmonary Circuit

Systemic Circuit

Question 12

Describe blood flow through the heart starting with venous blood from superior and inferior vena cava mention the four (4) hollow chambers of the heart, the tricuspid and bicuspid valves and the two semilunar valves

Answer 12

Deox blood from inferior and superior vena cava enter the right atrium and go through the tricuspid valve into the right ventricule then through the pulmonary semilunar valve into the pulmonary trunk and out to the lung capillaries through the pulmonary arteries.

The oxygenated blood then comes back from the lungs in the pulmonary veins into the left atrium and through the bicuspic valve into the left ventricle then through the aortic semilunar valve into the aorta and out to the systemic circuit.

Question 13

What prevents the blood from moving up into the atria during ventricular contraction?

Answer 13

The two atrioventricular (AV) valves found at each atrial-ventricular junction.

Bicuspid and tricuspid

Question 14

What two systems interact to regulate heart activity?

Answer 14

• The autonomic nervous system
• -> Nerves act like brakes or accelerators to increase or decrease heart rate.
• The intrinsic conduction system (nodal system)
• -> Built into heart tissue and sets its basic rhythm.

Question 15

Describe the intrinsic system

Answer 15

• Composed of tissue found nowhere else in the body, a mixture between muscle and nervous tissue
• Causes heart muscle depolarization in one direction – from atria to the ventricles
• Enforces a contraction rate of approx. 75 beats per minutes

Question 16

Describe the automatic depolarization of the SA node

Answer 16

The action potential begins when the pacemaker potential reaches threshold. Depolarization is due to Calcium influx through the Calcium channel.

Question 17

Describe the electrical conduction in the heart

Answer 17

From SA node, electrical signal spreads across atria causing contraction. Once wave of depolarization reaches the AV node, a delay allows atria to contract, emptying blood into ventricles before the latter contract. Fibers eventually branch out to distant ventricular tissues and are referred to then as Purkinje Fibers.

The rapid conduction of elec. signal coordinates contraction of heart chambers, giving efficient wringing action as the ventricular muscles contracts.

[AV node connected to bundle of special cells in the heart designed to conduct elec. signal rapidly through ventricles (av bundle)

AV branches downstream to a left and right bundle branch that conduct impuse through interventricular septum.]

Question 18

Why is there a delay when the wave of depolarization reaches the AV node?

Answer 18

To allow the atria to contract and empty blood into the ventricles before the ventricles are stimulated to contract.

Question 19

Understand the events of the cardiac cycle, understand the graph below (See objectives cardio)

Answer 19

ea. cardiac cycle = 0.8s

Contraction phase (systole)
Relaxation phase (diastole)

1. During diastole, atria and ventricules relaxed and AV valves open. De-ox blood flows into right atrium from supervior vena cava.

2, SA node fires triggering atria to contract. Pressure gradient generated across open AV valves. Rapid flow of blood into ventricles.

3. Ventricles in last part of the diastole have max blood when they contain EDV (end diastolic volume)
4. Atria relax and ventricles depolarize. Then begin contraction phase. Rise in P causes AV valves to close.

Isovolumetric contraction: Ventricular pressure rises rapidly with no blood ejection.. (same volume).

End-systolic volume: ESV

Slide 21 lecture 13

Question 20

Understand what is occurring in the 3 waves of the electrocardiogram (P wave, QRS complex and T wave)

Answer 20

ECG traces movement of electrical current across body.

P wave: Depolarizing of SA node
QRS Complex: Ventricular depolarizatifon.

T wave: Ventricular repolarization

Question 21

What is cardiac output and how is it calculated?

Answer 21

Cardiac output = Amount of blood pumped by the heart (each ventricle) in one minute

Measured in ml/min

CO= Stroke volume x heart rate

Cardiac reserve: Max % that cardiac output can increase above normal –> normal adult reserve is 300-400%

Question 22

What is stroke volume?

Answer 22

It is the volume of blood discharged from the ventricle with each contraction. (approx. 70 ml for an adult at rest in general)

Question 23

Understand the autonomic nervous system control of the heart (be able to label a diagram

Answer 23

Cluster of neurons in the medulla that controls heart rate.

Baroreceptors found in carotid sinus and aorta send info to medulla.

Sympathetic & parasympathetic send motor nerve impusles to heart.

(P. 32-33) Slide 13

Question 24

Know the various functions of blood

Answer 24

Transportation : Transports O2 from lungs to cells of body and CO2 away from cells to the lungs. Carries nutrients from GI tract to body cellls, heat and wast away from cells and hormones to celles.

Regulation: Regulates pH, adjust body temp. from coolant properties of H2O in plasma.

Protection: Blood can clot which protects excessive loss from cardiovascular sysem after injury. WBC protect against disease by carrying out antibodies.

Question 25

Know the various components of blood (including plasma proteins and formed elements)

Answer 25

Blood plasma: Watery liquid that contains dissolved substances.

Formed elements: Cells and cell fragments.

99% of formed elements are RBC = hematocrit.

1% WBC –> form buffy coat between packed RBCs and plasma

Question 26

Briefly describe hematopoiesis

Answer 26

Occurs in red bone marrow located in all bones of the skeleton.

As child ages, much of red bone marrow replace by yellow marrow.

By adulthood, hematopoiesis and red bone marrow is limited to the spongy bone in the cranial bones, ribs, sternum, pelvis, and proximal epiphyses of humeri and femurs.

Question 27

Be able to trace the path of blood from the heart back to the heart

Question 28

Briefly describe the 3 tunica layers of arteries and veins

Question 29

Briefly describe the blood brain barrier

Question 30

Briefly describe capillary beds

Question 31

How does venous blood return to the heart?

Question 32

Define Blood pressure

Question 33

Describe what happens to BP in systemic circulation with distance from left ventricle

Question 34

Explain Δ P = CO × R

Question 35

What is the relationship between cardiac output, peripheral resistance, blood volume and blood pressure

Question 36

How do you calculate cardiac output

Question 37

Describe (in detail) the sympathetic nervous system activities on heart rate and stroke volume, how does this affect CO and MAP?

Question 38

What are the three important sources of resistance

Question 39

Which two of these factors can be considered constant?

Question 40

What happens to resistance as the diameter of a tube gets smaller?

Question 41

How do the short-term regulation of blood pressure by the nervous system and blood-borne hormones work?

Question 42

What is the vasomotor center how does it affect peripheral resistance and thus BP

Question 43

How do chemoreceptors affect cardioacceleratory centers and what is the result on BP

Question 44

Describe the renin/angiotensin/aldosterone system, (know what stimulates (or activates) the release of each hormone, from which gland (or if they are in inactive form where they are activated) and the response of the effector organs)

Question 45

Just know that atrial natriuretic peptide (ANP) has the opposite effect

Question 46

Review ADH

Question 47

Describe the direct renal mechanism for (in response to) increased BP