Kin 1Aa3 Quiz 1

Front 1

Function OF CVS

Back 1

}transport mechanism for human body

Front 2

Functions of the Heart

Back 2

1. Generating blood pressure
2. Routing blood
3. Ensuring one-way blood flow
4. Regulating blood supply

Front 3

1. Generating blood pressure

Back 3

* flow = pressure/resistance. Flow is dictated by heart resistance, dictated by blood vessels
* heart beats ~ 4-5 L of blood/minute at rest

Front 4

1. Routing blood:

Back 4

1. separates pulmonary, systemic, chambers separate blood

Front 5

1. Ensuring one-way blood flow:

Back 5

1. valves (preventing backflow) , arteries use pressure

Front 6

1. Regulating blood supply

Back 6

* Changes in contraction rate and force match blood delivery to changing metabolic needs
* Example: riding a bike (blood flow to legs increase, blood flow to internal organs decrease)

Front 7

ARTERY AND VEIN

Back 7

AWAY AND TO THE HEART

Front 8

Where is the heart located?

Back 8

* mediastinum: area from the sternum to the vertebral column and between the lungs

Front 9

* parietal pleura

Back 9

* serous membrane lines thoracic cavity

Front 10

* pleura cavity:

Back 10

* serous fluid ( lubricate and reduce friction)

Front 11

* fibrous pericardium

Back 11

* tough CT, creates cavity of heart, outer line, separates heart and lungs, serous membrane

Front 12

* Apex

Back 12

* Blunt rounded point of cone. Directed anteriorly, inferiorly and to the left

Front 13

* Base

Back 13

* Flat part at opposite of end of cone. Directed posteriorly, superiorly and to the right

Front 14

* Heart Note

Back 14

* tilted left
* 1/3 mass on right, 2/3 left

Front 15

Superior right point:

Back 15

at the superior border of the 3rd right costal cartilage

Front 16

Superior left point:

Back 16

at the inferior border of the 2nd left costal cartilage 3cm to the left of midline

Front 17

Inferior left point:

Back 17

at the 5th intercostal space, 9 cm from the midline

Front 18

* Inferior right point

Back 18

* at superior border of the 6th right costal cartilage, 3 cm from the midline

Front 19

* palpation:

Back 19

* pushing down on structures outside of the body to feel for internal structures

Front 20

Pericardium

Back 20

or pericardial sac: cover around heart, creates cavity around heart

Front 21

Fibrous pericardium

Back 21

tough fibrous outer layer. Prevents over distention; acts as anchor outer most layer, tough fibrous outer layer, anchor for the heart >> attached to the diaphragm at bottom and vessels of the top. Prevents over dissenstion (can only grow or expand to a certain degree) the wall of the cavity. Separates heart from lungs

Front 22

Serous pericardium

Back 22

thin, transparent, inner layer. Simple squamous epithelium inner layer, double layer, serous membranes (continuous membrane with sera fluid) 1) parietal pericardium: in contact with the fibrous pericardium outer layer 2) visceral pericardium (pericardial sac): also called the epicardium (heart tissue), inner layer, close contact with the wall of the heart

Front 23

Parietal pericardium:

Visceral pericardium

Back 23

lines the fibrous outer layer

(epicardium): covers heart surface

* The two are continuous and have a pericardial cavity between them filled with pericardial fluid
* pericardial fluid: lubrication to protect from abrasion

Front 24

Epicardium

Back 24

– visceral layer of serous pericardium

Front 25

* Myocardium

Back 25

* – cardiac muscle layer is the bulk of the heart

Front 26

Endocardium

Back 26

* – chamber lining & valves - simple squamous with some underlying connective tissue, made up of cardiac muscle (trabeculae carneae)

Front 27

* Auricles

Back 27

* Auricles create pockets, are extensions of the atrias

Front 28

Sulci:

Back 28

grooves on surface of heart containing coronary blood vessels and fat

Front 29

* coronary sulcus

Back 29

* encircles heart and marks the boundary between the atria and the ventricles

Front 30

* anterior interventricular sulcus

Back 30

* marks the boundary between the ventricles anteriorly

Front 31

* posterior interventricular sulcus

Back 31

* marks the boundary between the ventricles posteriorly

Front 32

* right atrium:

Back 32

* receives blood from superior, inferior vena cava and the coronary sinus (brings blood back from the cardiac tissue)

Front 33

* tricuspid valve:

Back 33

* AV value, separates atria from the ventricle, 3 cusp

Front 34

* right ventricle:

Back 34

* has muscles cone shaped, raised bundles of cardiac tissue: papillary muscles (contract) attached to the chord tendineae (also attaches onto the valves which keeps them functioning)

Front 35

* pulmonary semilunar valve:

Back 35

* allows blood to flow to the lounge and stops blood from moving back into the right ventricle

Front 36

* pulmonary trunk:

Back 36

* splits in to the right and left pulmonary artery to give blood to both lungs

Front 37

* left atrium

Back 37

* receiving blood from lungs, has bicuspid valve

Front 38

* bicuspid valve

Back 38

two cusps

Front 39

* left ventricle:

Back 39

* walls thicker because it has to pump blood to the rest of the body, papillary muscles, chord tendinae

Front 40

* interventricular septum

Back 40

* thickened area that separates ventricle

Front 41

* aortic semilunar valve:

Back 41

* blood from the left ventricle to the aorta

Front 42

Relaxed Left Ventricle

Back 42

cardiac muscle is relaxed and the papillary muscles are also relaxed which allows for low tension on the chordae tendinae. Blood coming back from the lungs so there is more pressure in the atrium compared to ventricle because it is empty. This allows for filling to occur. High pressure in the aorta and low pressure from the ventricle allows for the semilunar valve to stay closed and the AV valve to remain open for filing

Front 43

Contracted Left Ventricle

Back 43

atria contract before ventricle and than the ventricle begins to contract. This makes the volume smaller and the pressure higher inside the heart and it also contracts the papillary muscles which holds the valves to stop from inversion into the atrium. Blood pressure pushed AV valves closed. Semi lunar valves are pushed open when blood pressure in heart is greater than in the aorta

Front 44

Valves:

Back 44

ensures one-way flow of blood

Front 45

Atrioventricular valves (AV valves)

Back 45

• Leaf-like cusps attached to papillary muscles by tendons (chordae tendineae). Right has three cusps (tricuspid). Left has two cusps (bicuspid, mitral). When valve is open, canal is atrioventricular canal.

Front 46

Semilunar valves

Back 46

• Right (pulmonary); left (atrial). Each cusp is shaped like a cup. When cusps are filled, valve is closed; when cusps are empty, valve is open

Front 47

Coronary Circulation

Back 47

* Coronary circulation is blood supply to the heart
* Heart as a very active muscle needs lots of O2
* When the heart relaxes high pressure of blood in aorta pushes blood into coronary vessels
* Many anastomoses

Front 48

* anastomoses
*

Back 48

* connections between arteries supplying blood to the same region, provide alternate routes if one artery becomes occluded

Front 49

• Right coronary artery

Back 49

exits aorta just superior to point where aorta exits heart; lies in coronary sulcus. Extends to posterior aspect of heart

* Right marginal artery (lateral wall of right ventricle)
* Posterior interventricular artery lies in posterior interventricular sulcus, supplies posterior and inferior aspects of heart

Front 50

Left coronary artery

Back 50

exits aorta near right coronary. Branches

* Anterior interventricular artery (left anterior descending artery) in anterior interventricular sulcus important because it supplies a large part of left ventricle

* Left marginal artery supplies lateral wall of left ventricle
* Circumflex artery extends to posterior aspect

Front 51

Great cardiac vein:

Back 51

drains left side of the heart

Front 52

Small cardiac vein:

Back 52

drains right margin of heart

Front 53

Coronary sinus:

Back 53

large venous cavity, empties into right atrium, merging point of many veins

Front 54

Heart Skeleton

Back 54

fibrous CT plate that separates atrium and ventricle

* forms rings around valves: provides structural support
* provides attachment point for cardiac muscle
* provide barrier for electrical signals of ventricles and atria

Front 55

Cardiac Muscle

Back 55

• Elongated, branching cells containing 1-2 centrally located nuclei (centrally located)

• Contains actin and myosin myofilaments

* lots of mitochondria (constant supply of ATP)
* T tubes are wider and wrap around myofibrils at Z disks
* SR are near T tubes at certain points, can sense AP
* no terminal cistera
* Intercalated disks
* Electrically, cardiac muscle of the atria and of the ventricles behaves as single unit
* desmosome:

Front 56

* Intercalated disks:

Back 56

* specialized cell-cell contacts; connect point between 2 cardiac cells >> electrical synapse: gap junctions >> connecting cytoplasm of cells to other neighbouring cells >> which allows signal to carry through all cells

Front 57

* desmosome:

Back 57

* specialized structures that connects cells together

Front 58

* SA node:

Back 58

* sinoatrial node. Generate spontaneous action potentials. Action potentials pass to atrial muscle cells and to the AV node; pacemaker of heart, dictates the speed of AP, the faster, in right atrium close to the superior vena cava entry point

Front 59

* AV node:

Back 59

* atrioventricular node. Action potentials conducted more slowly here than in any other part of system. Ensures ventricles receive signal to contract after atria have contracted; fires (depolarizes) after SA, located between inter-atrial septum, close to AV valves, fewer gap junctions

Front 60

Conducting System of the heart

Back 60

- SA node

- AV node

* these cells have fewer myofibrils
* - different ion channels
* - may have different diameters and number of gap junctions
* AV bundle
* right and left bundle branches
* purkinje fibres

Front 61

* AV bundle:

Back 61

* passes through hole in cardiac skeleton to reach interventricular septum; brings signal to ventricle, AP speeds up

Front 62

* Right and left bundle branches:

Back 62

* extend beneath endocardium to apices of right and left ventricles

Front 63

* Purkinje fibers:

Back 63

* Large diameter cardiac muscle cells with few myofibrils. Many gap junctions. Conduct action potential to ventricular muscle cell, conduct AP quickly send electrical signal to nonspecialized cardiac muscle cells

Front 64

Cardiac muscle action potential

Back 64

Resting state:

• High extracellular Na+ and Ca2+; high intracellular K+
1) Depolarization: Na+ influx (Na+ channels opened, K+ channels close, Ca2+ channels start to open)

2) Early repolarization: Some voltage-gated K+ channels open, causing early repolarization. (Na+ channels close)
Plateau Phase: some Ca2+ channels are open, producing the plateau by slowing further repolarization; lengthens AP

3) Final repolarization: many K+ channels open, Ca2+ channels close

• Na+/K+ ATPase (“pump”) restores ion gradient

Front 65

Differences Between Skeletal and Cardiac Muscle Physiology

Back 65

• Cardiac: action potentials conducted from cell to cell. Skeletal: action potential conducted along length of single fiber

• Cardiac: rate of action potential propagation is slow because of gap junctions and small diameter of fibers. Skeletal: it is faster due to larger diameter fibers.

• Cardiac: calcium-induced calcium release (CICR). Movement of Ca2+ through plasma membrane and T tubules into sarcoplasm stimulates release of Ca2+ from sarcoplasmic reticulum

Front 66

Autorhythmicity: SA Node Action Potential

Back 66

* Self-generating action potentials in regular time intervals

1) Pacemaker potential: Na+ “leakage” into cell, causes resting membrane potential to move towards threshold.

• Inside of cell becomes more electrically positive.

• K+ channels closing

2) Depolarization phase:

• Ca2+ channels open, K+ channels closed

3) Repolarization phase:

* Ca2+ channels close, K+ channels open

Front 67

** Notes

Back 67

* pacemaker cells generate own AP
* SA node forces at faster rate >> stimulates cells: key pacemaker for the heart
* resting membrane potential: -60 (pacemaker potential)
* Na+ leak channels
* depolarization: voltage gated Ca2+ close, K+ opens
* happens continually

Front 68

Refractory Period

Back 68

* Absolute: Cardiac muscle cell completely insensitive to further stimulation
* Relative: Cell exhibits reduced sensitivity to additional stimulation
* Long refractory period prevents tetanic contractions
* heart needs to relax for the chambers to actually fill

Front 69

Electrocardiogram - ECG

Back 69

Record of electrical event in the myocardium that can be correlated with mechanical events (contraction, relaxation, valves open and close)

Front 70

P wave:

Back 70

* depolarization of atrial myocardium. Signals onset of atrial contraction, when SA node first fires

Front 71

QRS complex:

Back 71

* ventricular depolarization and signals onset of ventricular contraction. Repolarization of atria simultaneously. Bigger because ventricles work harder, atria begins to relax

Front 72

* T wave:

Back 72

* repolarization of ventricles; precedes ventricular relaxation

Front 73

PQ interval

Back 73

* or PR interval: 0.16 sec; atria contract and begin to relax, how long it takes for atria to contract and relax

Front 74

QT interval:

Back 74

* 0.36 sec; ventricles contract and begin to relax, time it takes for ventricles to contract and relax

Front 75

Cardiac Cycle

Back 75

* happens is a single heartbeat
* Heart is two pumps that work together, right and left half

• Repetitive contraction (systole) and relaxation (diastole) of heart chambers

• Blood moves through circulatory system from areas of higher to lower pressure.

– Contraction of heart produces the pressure

Front 76

Systolic state

Back 76

(2 phases): chamber contracts and ejects blood

• Phase 1: Isovolumetric contraction
• Phase 2: Ejection

Front 77

Diastolic state

Back 77

* (3 phases): chamber fills with blood

• Phase 3: Isovolumetric relaxation
• Phase 4: Passive ventricular filling
• Phase 5: Active ventricular filling (atrial systole)

Front 78

What artery is called they widow maker

Back 78

anterior interventricular artery: left anterior descending,

important because it supplies a large part of left ventricle.

Called widow maker because if it is blocked the left side of the heart will die and person will die because left ventricle supplies body with blood