Cardiovascular System

Question 1

Learning Outcomes:

Answer 1

• Describe the anatomy of the heart and identify the gross anatomical features including the great vessels and the vessels supplying and draining the heart.
• Describe the cardiac cycle.
• Relate an ECG to the electrical and mechanical changes occurring in the heart
  during the heart cycle.
• Define cardiac output and describe the effect of the autonomic nervous
  system on heart rate and stroke volume.
• Describe the structure of blood vessels.

Question 2

Cardiovascular system

Answer 2

Cardiovascular system = heart and blood vessels
Circulatory system = heart, blood vessels, and blood
Functions of circulatory system:
* Transport
* 02, CO, nutrients, wastes, hormones
* Protection
* Regulation
* citainmation, limit spread of infection, destroy microrganisms and cancer cell, neutralize toxins, and initiate
* Fluid balance, stabilizes pH of extracellular fluid (ECF), and temperature control

Question 3

The Pulmonary & Systemic Circuits

Answer 3

2 major divisions of circulatory system:
* Systemic circuit:
* Supplies oxygenated blood to all tissues of the body and returns it to the heart
* Pulmonary circuit:
* Carries blood to lungs for gas exchange and back to heart

Question 3

Position of the Heart

Answer 3

in the thoracic cavity
posterior to the sternum
Anterior to the vertebral column
Medial to the lungs
: In the mediastium
Surrounded by the pericardium

Question 4

Position of the Heart

Answer 4

Question 5

The Pulmonary & Systemic Circuits photo

Answer 5

Question 6

Blood flow

Answer 6

Basic plan:
2 pumps: right & left
Each pump has 2 chambers
Ventricles pump blood
atria receive blood
* Valves ensure blood flows in one direction only
arteries take blood away from the heart
Veins carry blood back to heart
Capillaries are small vessels connecting arteries to veins

Question 7

Heart chambers photo

Answer 7

Question 7

Posterior view of the heart photo

Answer 7

Question 8

Anterior view of the heart photo

Answer 8

Question 9

Blood Flow photo

Answer 9

Question 10

Coronary circulation

Answer 10

5% of blood pumped by heart goes to the heart itself through the coronary circulation.
* Heart needs abundant O, and nutrients to sustain its workload.
* Most coronary blood returns to R atrium via the coronary sinus. (Some returns directly into R ventricle via cardiac veins.)

Question 11

Coronary circulation photo

Answer 11

Question 12

Valves

Answer 12

Question 12

Eletrocardiogram (ECG or EKG)

Answer 12

Question 13

“Lub-dub”

Answer 13

Ventricles contract:
* internal pressure rises
* AV valves close = “Lub”’
* semilunar valves pushed open
* blood flows into aorta and pulmonary trunk
Ventricles relax:
* expand & internal pressure falls
* Semilunar valves close as blood attempts to flow
back into the ventricles from the vessels = “Dub”
* AV valves open: blood flows from the atria into the ventricles.

Question 14

“Lub-dub” photo

Answer 14

Question 14

Valves

Answer 14

Question 15

Pericardium

Answer 15

• Double-walled sac that encloses the heart
• Allows heart to beat without friction, provides room to expand, yet resists excessive expansion
• Anchored to diaphragm inferiorly and sternum anteriorly
• Fibrous pericardium: Outer wall, not attached to heart
• Serous pericardium
• Parietal layer: lines fibrous pericardium
  /. Visceral layer (epicardium): covering heart surface
  ** Pericardial cavity-space between parietal and visceral layers of serous pericardium, filled with pericardial fluid
  peri = around; cardi = heart; pariet = wall; visceralis = internal; serous/serum = whey

Question 16

The heart wall

Answer 16

3 layers: epicardium, myocardium, and endocardium
* Epicardium (epi = upon, cardi = heart)
* = visceral layer of serous pericardium
* Serous membrane covering heart
Sonolary bamd espith erum tver vin thin layer of lose CT
* Myocardium (myo = muscle)
* Cardiac muscle
* Muscle spirals around heart which produces wringing motion.
* Fibrous skeleton of the heart
* Framework of collagen and elastic fibers
* Provides structural support and attachment for cardiac muscle & valves
* Electrical insulation between atria and ventricles
* Endo cardium lene inint orlart and blood vessels
* Simple squamous epithelium overlying thin layer of loose CT

Question 17

The heart wall photo

Answer 17

Question 18

Cardiac muscle

Answer 18

Cardiomyocytes: striated, short, thick, branched cells, one central nucleus
Intercalated discs: join cardiomyocytes end to end with three features:
* Interdigitating folds: folds interlock with each other, and increase surface area of contact
* Desmosomes: Mechanical junctions tightly join cardiomyocytes
* Gap junctions: Electrical junctions allow ions to flow between cells.

DIG

Question 19

Intercalated discs

Answer 19

: Contractions of the heart originate within muscle cels themselves (myogenic
Contractions are triggered by pacemaker cells in the sinoatrial node and atrioventricular node
Electrical signal is transmitted by a nerve-like conduction pathway in the myocardium
Cardiac muscle cells contract on their own but are regulated by autonomic nervous system

Question 20

Conduction system

Answer 20

1. Sinoatrial node (Pacemaker): modified cardiomyocytes
   * In right atrium near base of superior vena cava

initates each heartbeat and determins heart beat

2. Excitation spreads through atrial myocardium
3. Atrioventricular (AV) node:

Near the right AV valve
Electrical gateway to the ventricles

Excitation spreads down to:
Atrioventricular
4. Atrioventricular (AV) bundle (Bundle of His): bundle

into right and left bundle branches
branches pass though interventricular septum towards apex

5. Subendocardial conducting network (Purkinje fibers): nerve like processes distribute excitation through ventricular myocardium.
   Cardiomyocytes: then pass signal from cell to cell via gap junctions.
   Entire myocardium of two atria or two ventricles acts like single, unified cell.
   Fibrous skeleton: insulator prevents currents from getting to ventricles by any other route.
   Heart rate in adult (at rest): 70 to 80 bpm (vagal tone).

Answer 20

Answer 21

Question 22

Cardiac cycle

Answer 22

Question 23

Cardiac cycle

Answer 23

VFICVEIR

Answer 23

Answer 24

Answer 25

Answer 26

Answer 27

Question 27

The Blood Vessel Wall

Answer 27

Question 28

General Anatomy of the Blood Vessels

Answer 28

* Three categories of blood vessels: * Arteries: carry blood away from heart * Veins: carry blood back to heart * Capillaries: connect smallest arteries to smallest veins to create a circuit

Question 29

arteries

Answer 29

Question 29

Capillaries

Answer 29

Question 30

Veins

Answer 30

Question 31

Venous Return

Answer 31

Question 32

Pulmonary Circuit

Answer 32

Question 32

Branches of the Abdominal Aorta

Answer 32

Question 32

Circulatory Pathways

Answer 32

Question 33

Branches of thoracic aorta

Answer 33

Question 34

Major Systemic Veins

Answer 34

Question 35

Blood

Answer 35

Answer 36

Answer 37

Question 37

Erythrocytes

Answer 37

Question 38

Homeostasis: Blood pressure Heart rate

Answer 38

Question 39

Arterial Sense Organs

Answer 39

Answer 40

Answer 41

Answer 42

Answer 43

Answer 43

Answer 43

Answer 44

Answer 45

Answer 45

Answer 47

Answer 48

Answer 49

Answer 49

Answer 50

Answer 51

Answer 52