CIRCULATORY SYSTEM PT 1 - HEART

Question 1

Describe the size/positioning/inferior attachment of the Heart.

Answer 1

• Size of a fist
• Middle of the mediastinum with 2/3rds of mass on the left
• Attached to diaphragm inferiorly

Question 2

The inferior portion of the heart is called?

Answer 2

Apex

Question 3

The superior portion of the heart is called?

Answer 3

Base

Question 4

Define Mediastinum.

Answer 4

Mass of organs between Lungs

Question 5

Name the structures that border the Mediastinum.

Answer 5

Superior: 1st rib
Inferior: Diaphragm
Anterior: Sternum
Posterior: Vertebrae

Question 6

What are the structures that make up the Mediastinum?

Answer 6

Trachea
Esophagus
Thymus/Lymph Nodes
Heart

Question 7

What is Pericardium? Name the layers.

Answer 7

A two-layered CT membrane surrounding Heart

Fibrous and Serous

Question 8

Describe Fibrous Pericardium.

Answer 8

A inelastic, dense irregular CT holding Heart in place and allows movement

Question 9

Describe Serous Pericardium.

Answer 9

Deep to Fibrous, forming a double layer around Heart

Question 10

Describe the Parietal Layer of the Serous Pericardium.

Answer 10

Outer layer fused to Fibrous Pericardium

Question 11

Describe the Visceral Layer of the Serous Pericardium.

Answer 11

aka. Epicardium

Inner layer attached to Heart muscle

Question 12

What is the Pericardial Cavity?

Answer 12

Space between the Parietal and Visceral layer filled with pericardial fluid to reduce friction

Question 13

Name the layers that make up the Hearts walls. From superficial to deep.

Answer 13

Epicardium
Myocardium
Endocardium

Question 14

Describe the Epicardium layer.

Answer 14

aka. Visceral layer of Serous Pericardium

Outer layer of simple squamous epithelium and CT with a smooth, slippery texture

Question 15

Describe the Myocardium layer.

Answer 15

Cardiac muscle tissue - site of contractions

Question 16

Describe the Endocardium layer.

Answer 16

Deep layer providing a smooth lining for chambers and valves

Question 17

Describe Endothelium.

Answer 17

Simple squamous epithelium lining cavities of heart, blood and lymph vessels. Found in Endocardium layer

Question 18

What is a Septa?

Answer 18

Dividing walls in heart

Question 19

What does the Interatrial Septum divide?

Answer 19

Divides 2 Atria

Question 20

What does the Interventricular Septum divide?

Answer 20

Divides 2 ventricles

Question 21

What is the function of Veins?

Answer 21

Carry blood towards Heart

Question 22

What is the function of Arteries?

Answer 22

Carry blood away from Heart

Question 23

Explain the blood flow function of the Right Atrium.

Answer 23

• Receives blood from 3 veins
• Exits through the Tricuspid Valve (Right A-V Valve)
• Into the Right Ventricle

Question 24

Name the 3 veins entering the Right Atrium.

Answer 24

Superior Vena Cava
Inferior Vena Cava
Coronary Sinus

Question 25

Explain the blood flow function of the Right Ventricle.

Answer 25

- Receives blood from Right Atrium - Ejects through Pulmonary Semilunar Valve - Into the Pulmonary Trunk - Suppling R and L Pulmonary Arteries (Lungs)

Question 26

Explain the blood flow function of the Left Atrium.

Answer 26

- Receives blood from 4 veins (from lungs) - Exits through Bicuspid/Mitral Valve (Left A-V Valve) - Into the Left Ventricle

Question 27

Explain the blood flow function of the Left Ventricle.

Answer 27

- Receives blood from Left Atrium - Ejects through Aortic Semilunar Valve - Into the Aorta and Coronary Arteries

Question 28

What are Chordae Tendinae?

Answer 28

Tendon-like cords on the cusps of the AV Valves

Question 29

What is the function of Papillary Muscles?

Answer 29

Prevents valves from opening in opposite direction

Question 30

Explain the opening and closing of the Atrioventricular Valves (Tricuspid and Bicuspid Valves).

Answer 30

- Blood flow into the Atriums causes pressure which opens the AV Valves into the Ventricles. - AV Valves closes when ventricles contract

Question 31

Explain the function of the Pulmonary/Aortic Semilunar Valves.

Answer 31

- Ventricles contract opening the Pulmonary and Aortic Valves into the Arteries - Once ventricles relax, left over blood will flow into the cusps of the semilunar valves

Question 32

What is the "Lub" sound from the Heart?

Answer 32

Sound of AV Valves closing

Question 33

What is the "Dub" sound from the Heart?

Answer 33

Sound of Semilunar Valves closing

Question 34

Explain the Pulmonary Circulation Pathways.

Answer 34

- 'Right side of the Heart' - Deoxygenated blood enter Right Atrium - Pumped into Right Ventricle - Up into the Pulmonary Arteries (Lungs) - Deoxygenated blood rid CO2 for O2 in Lungs - Oxygenated blood from Lungs enter the Left Atrium via 4 Pulmonary Veins

Question 35

Explain the Systemic Circulation Pathways.

Answer 35

- 'Left side of the Heart' - Oxygenated blood enter Left Atrium from Lungs - Pumped into Left Ventricle - Up into Aorta and out to body tissues - Tissues use O2 and releases CO2 making it deoxygenated, which eventually goes in Right Atrium

Question 36

Describe Coronary Circulation.

Answer 36

Heart provides own circulation, with coronary arteries encircling the Heart, and receiving blood supply in between beats

Question 37

Describe Autorhythmic Fibres?

Answer 37

Self-excitable cardiac muscle cells generating own APs - Sets rhythm of APs for contactions - Form a conducting system

Question 38

Explain the Conducting System of the Heart.

Answer 38

A pathway at which APs progress through the heart

Question 39

List the sequence of an AP through the Heart (Conduction System).

Answer 39

``` SA Node (Sinoatrial Node) Atria AV Node (Atrioventricular Node) B. of His B. Branches Purkinje Firbres Ventricles ```

Question 40

Describe the Sinoatrial Node (SA Node).

Answer 40

Repeatedly generates APs causing atrial contraction and ejection of blood into the AV node

Question 41

Describe Atrioventricular Node (AV Node).

Answer 41

Causes ventricular contraction and ejection of blood into the arteries

Question 42

Define Cardiac Cycle

Answer 42

All events associated in one heart beat

Question 43

Define Systole.

Answer 43

Contraction phase

Question 44

Define Diastole.

Answer 44

Relaxation phase

Question 45

Define Heart Rate and average HR.

Answer 45

- Heart beats in 1 min | - Avg. HR 72bpm

Question 46

Define Strike Volume and average SV

Answer 46

- Blood ejected from each ventricle with each beat | - Avg. SV 70mL

Question 47

Define Cardiac Output and average CO.

Answer 47

- Heart rate x Stroke Volume | - 5L/min

Question 48

Define Cardiac Output.

Answer 48

Amount of blood ejects per minute

Question 49

What are the factors that regulate HR?

Answer 49

ANS Hormones/Ions Other Factors (age/sex/fitness/body temp.)

Question 50

The control centre in the _______________ gets input from sensory receptors and high brain centres to regulate HR.

Answer 50

Medulla Oblongata

Question 51

An increased SyNS, will __________ HR

Answer 51

Increase

Question 52

An increased PaNS, will __________ HR

Answer 52

Decrease

Question 53

Which Hormones/Ions increase HR and contractility?

Answer 53

- Epinephrine/Norepinephrine - Thyroid - Calcium

Question 54

Which Hormones/Ions is needed for normal APs, and elevate blood levels and decrease HR?

Answer 54

Sodium and Potassium

Question 55

What 3 factors help maintain equal stroke volume?

Answer 55

Preload Contractility Afterload

Question 56

Define the Frank-Starling Law.

Answer 56

Degree of stretch = Greater contraction

Question 57

Define the Preload factor that helps maintain equal stroke volume.

Answer 57

Amount of stretch equals to volume of blood that fills the ventricles at the end of diastole (end diastolic volume)

Question 58

Define the Contractility factor that helps maintain equal stroke volume.

Answer 58

Strength of contraction at given Preload

Question 59

Define the Afterload factor that helps maintain equal stroke volume.

Answer 59

Pressure in ventricles must overcome pressure in vessels before semilunar valves can open