Cardiovascular physiology - video 2

Cardiovascular physiology - video 2

The contraction of the heart

Firstly, lets consider the contraction and flow of bood through he heart

Multiple Choice

What percentage of atrial blood drains directly into ventricles before atrial contraction?

• 30%

• 35%

• 70%

• 55%

Multiple Choice

What is the time delay between atrial contraction and ventricular contraction?

• 1.0s

• 0.04s

• 0.16s

• 0.08s

Location and protection of the heart

The heart is located behind the sternum and is protected and held in place by a protectice sac know as the pericardium.

The pericardium has different 'layers'

Its a little like pushing your fist into a balloon that is not inflated much.

Multiple Choice

The outer layer of heart protection is provided by the

• Epicardium

• Myocardium

• Parietal pericardium

• Fibrous pericardium

Multiple Select

The fibrous pericardium serves 2 more purposes, n addition to protection what are they?

• Keep the heart warm

• Prevents the heart from over filling / swelling

• Reduces the heart noise level

• Secures the heart in it position

Multiple Select

The parietal and visceral (epicardium) are composed of which 2 types of tissue?

• Epithelium cells

• Columnar cells

• Areolar tissue

• myocardial cells

The heart wall

The heart is made of 3 'layers of tissue that are different types and different 'thicknesses'

They pumping action of the heart is separated from the paretial pericardium by a cavity containing fluid.

Multiple Choice

The purpose of the pericardial cavity is to

• Allow for oxygen supply to the heart

• reduce the friction between the heart and the parietal pericardium

• Enable the heart to work as a 4 chamber pump

• Insulate the heart

Multiple Choice

The thickest layer of the heart wall is the

• Parietal pericardium

• Endocardium

• Myocardium

• epicardium

Myocardial cells

Myocardial cells form the myocardium and are similar in structure to skeletal muscle cells. They are striated and are organised into sarcomeres composed of actin, myosin and z-discs.

They also have several key differences in terms of structure and function

Multiple Choice

The myocardium is under the control of the

• Somatic nervous system

• The peripheral nervous system

• The central nervous system

• The autonomic nervous system

Multiple Select

Myocardial cells are

• Shorter than skeletal muscle cells

• Longer then skeletal muscle cells

• Insulated from each other

• Branch to form more than one cell

Multiple Choice

The intercalated disc facilitates wha

• Insulation for the end of the muscle fibre

• Transmission of the electrical impulse between muscle fibers in series

• Space for blood vessels to pass through

Multiple Choice

The structure of the myocardium allows the depolarisation and contraction of the myocardium to occur

• In unison

• Segmentally

• in a wave like manner

• Maximally

The heart valves

The valves of the heart separate the upper and lower chambers and the ventricles from the heart circulatory systems

They also enable the one way flow of blood between the atria and ventricles and the ventricles and circulatory systems

Valve structure

• The atrioventricular (AV) valves have differing numbers of cusps

• The AV valves have specialist structures and muscles that prevent backflow from ventricles to atria during ventricular contraction

• The semilunar valves have cusps that are structured in a half moon shape.

Multiple Select

A combination of what prevents back flow into the atria during ventricular contraction

• Endothelium

• Cordae tendineae

• AV prolapse limitors

• Papillary muscle

Multiple Choice

The myocardial wall is thickest around the

• Right ventricle

• Left ventricle

• Left atrium

• Right atrium

The electrical activity of the heart

• The heart is stimulated to contract by a specialist group of cells called the pacemaker.

• Electrical activity (cardiac action potential) spreads across the heart to stimulate contraction of the myocardium

• The composite electrical signal produced by the hearts electrical activity is called an ECG / EKG

The Electrocardiograph (ECG)

The ECG is a composite recording of the different phases of electrical activity that spreads across the heart during a single heart beat.

Multiple Choice

What does a HR transmitter use to determine mean HR in bpm

• The time between consecutive P waves

• The mean time for 5 consecutive R-R intervals

• The level of S-T segment depression

• None of the above

Multiple Choice

The p wave represents the

• Ventricular contraction

• Atrial contraction

• Ventricular relaxation

• Atrial relaxation

Multiple Choice

The QRS wave represents the

• Atrial contraction

• Atrial relaxation

• Ventricular contraction

• Ventricular relaxation

Multiple Choice

The T wave represents

• Atrial relaxation

• Atrial contraction

• Ventricular contraction

• Ventricular relaxation

Multiple Choice

A 2mm depression of the ST segment is indicative of

• Heart failure

• Reduced myocardial blood and oxygen supply

• Increased heart rate

• AV block

Multiple Choice

The tunica media is thicker in the

• Arteries

• Veins

Multiple Choice

The natural rhythm of the hearts pacemaker is

• 70bpm

• 150bpm

• 100bpm

• 50bpm

Multiple Choice

What is the name of the structure that insulates the upper chambers of the heart from lower chambers.

• Cardiac insulator band

• Cardiac skeleton

• AP block tissue

• Signal limiter tissue

Multiple Choice

The electrical signal is passed to the ventricles from the AV node via

• The AV bundle

• The bundle of HIS

• The left and right bundle branches

• Purkinje fibers

• All of the above are correct