CIRCULATORY SYSTEM PT 1 - HEART Flashcards

1
Q

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

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

The inferior portion of the heart is called?

A

Apex

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3
Q

The superior portion of the heart is called?

A

Base

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4
Q

Define Mediastinum.

A

Mass of organs between Lungs

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5
Q

Name the structures that border the Mediastinum.

A

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

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6
Q

What are the structures that make up the Mediastinum?

A

Trachea
Esophagus
Thymus/Lymph Nodes
Heart

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7
Q

What is Pericardium? Name the layers.

A

A two-layered CT membrane surrounding Heart

Fibrous and Serous

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8
Q

Describe Fibrous Pericardium.

A

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

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9
Q

Describe Serous Pericardium.

A

Deep to Fibrous, forming a double layer around Heart

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10
Q

Describe the Parietal Layer of the Serous Pericardium.

A

Outer layer fused to Fibrous Pericardium

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11
Q

Describe the Visceral Layer of the Serous Pericardium.

A

aka. Epicardium

Inner layer attached to Heart muscle

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12
Q

What is the Pericardial Cavity?

A

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

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13
Q

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

A

Epicardium
Myocardium
Endocardium

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14
Q

Describe the Epicardium layer.

A

aka. Visceral layer of Serous Pericardium

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

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15
Q

Describe the Myocardium layer.

A

Cardiac muscle tissue - site of contractions

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16
Q

Describe the Endocardium layer.

A

Deep layer providing a smooth lining for chambers and valves

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17
Q

Describe Endothelium.

A

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

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18
Q

What is a Septa?

A

Dividing walls in heart

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19
Q

What does the Interatrial Septum divide?

A

Divides 2 Atria

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20
Q

What does the Interventricular Septum divide?

A

Divides 2 ventricles

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21
Q

What is the function of Veins?

A

Carry blood towards Heart

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22
Q

What is the function of Arteries?

A

Carry blood away from Heart

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23
Q

Explain the blood flow function of the Right Atrium.

A
  • Receives blood from 3 veins
  • Exits through the Tricuspid Valve (Right A-V Valve)
  • Into the Right Ventricle
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24
Q

Name the 3 veins entering the Right Atrium.

A

Superior Vena Cava
Inferior Vena Cava
Coronary Sinus

25
Q

Explain the blood flow function of the Right Ventricle.

A
  • Receives blood from Right Atrium
  • Ejects through Pulmonary Semilunar Valve
  • Into the Pulmonary Trunk
  • Suppling R and L Pulmonary Arteries (Lungs)
26
Q

Explain the blood flow function of the Left Atrium.

A
  • Receives blood from 4 veins (from lungs)
  • Exits through Bicuspid/Mitral Valve (Left A-V Valve)
  • Into the Left Ventricle
27
Q

Explain the blood flow function of the Left Ventricle.

A
  • Receives blood from Left Atrium
  • Ejects through Aortic Semilunar Valve
  • Into the Aorta and Coronary Arteries
28
Q

What are Chordae Tendinae?

A

Tendon-like cords on the cusps of the AV Valves

29
Q

What is the function of Papillary Muscles?

A

Prevents valves from opening in opposite direction

30
Q

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

A
  • Blood flow into the Atriums causes pressure which opens the AV Valves into the Ventricles.
  • AV Valves closes when ventricles contract
31
Q

Explain the function of the Pulmonary/Aortic Semilunar Valves.

A
  • 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
32
Q

What is the “Lub” sound from the Heart?

A

Sound of AV Valves closing

33
Q

What is the “Dub” sound from the Heart?

A

Sound of Semilunar Valves closing

34
Q

Explain the Pulmonary Circulation Pathways.

A
  • ‘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
35
Q

Explain the Systemic Circulation Pathways.

A
  • ‘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
36
Q

Describe Coronary Circulation.

A

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

37
Q

Describe Autorhythmic Fibres?

A

Self-excitable cardiac muscle cells generating own APs

  • Sets rhythm of APs for contactions
  • Form a conducting system
38
Q

Explain the Conducting System of the Heart.

A

A pathway at which APs progress through the heart

39
Q

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

A
SA Node (Sinoatrial Node)
Atria
AV Node (Atrioventricular Node)
B. of His
B. Branches
Purkinje Firbres
Ventricles
40
Q

Describe the Sinoatrial Node (SA Node).

A

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

41
Q

Describe Atrioventricular Node (AV Node).

A

Causes ventricular contraction and ejection of blood into the arteries

42
Q

Define Cardiac Cycle

A

All events associated in one heart beat

43
Q

Define Systole.

A

Contraction phase

44
Q

Define Diastole.

A

Relaxation phase

45
Q

Define Heart Rate and average HR.

A
  • Heart beats in 1 min

- Avg. HR 72bpm

46
Q

Define Strike Volume and average SV

A
  • Blood ejected from each ventricle with each beat

- Avg. SV 70mL

47
Q

Define Cardiac Output and average CO.

A
  • Heart rate x Stroke Volume

- 5L/min

48
Q

Define Cardiac Output.

A

Amount of blood ejects per minute

49
Q

What are the factors that regulate HR?

A

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

50
Q

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

A

Medulla Oblongata

51
Q

An increased SyNS, will __________ HR

A

Increase

52
Q

An increased PaNS, will __________ HR

A

Decrease

53
Q

Which Hormones/Ions increase HR and contractility?

A
  • Epinephrine/Norepinephrine
  • Thyroid
  • Calcium
54
Q

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

A

Sodium and Potassium

55
Q

What 3 factors help maintain equal stroke volume?

A

Preload
Contractility
Afterload

56
Q

Define the Frank-Starling Law.

A

Degree of stretch = Greater contraction

57
Q

Define the Preload factor that helps maintain equal stroke volume.

A

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

58
Q

Define the Contractility factor that helps maintain equal stroke volume.

A

Strength of contraction at given Preload

59
Q

Define the Afterload factor that helps maintain equal stroke volume.

A

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