Practical 4. Human Physiology

Question 1

What is voluntary muscle contraction the result of ?

Answer 1

Communication between the brain and individual muscle fibres of the musculoskeletal system

Question 2

What results in muscle contraction ?

Answer 2

A thought being transformed into electrical impulses that travel down interneurons and motor neurons to the neuromuscular junctions that form a motor unit

Question 3

What is a hand dynamometer used for ?

Answer 3

Measuring maximum grip strength

Question 4

What are the initials for an electrocardiogram ?

Answer 4

ECG or EKG

Question 5

What is an electrocardiogram ?

Answer 5

A graphical recording of the electrical events occurring within the heart

Question 6

What initiates an electrical sequence in a healthy heart ?

Answer 6

The pacemaker in the right atrium specifically the sinoatrial node

Question 7

What does the impulse pass down ?

Answer 7

Conduction pathways between the atria to the atrioventricular node and from there to both ventricles

Question 8

What do conduction pathways facilitate ?

Answer 8

Orderly spread of the impulses and coordinated contraction of first the atria and then the ventricles

Question 9

What does electrical conductance create ?

Answer 9

Unique deflections in the ECG that give information about heart function and health

Question 10

What is the p-wave ?

Answer 10

Represents atrial depolarisation

Question 11

What does atrial depolarisation result in ?

Answer 11

Atrial contraction

Question 12

What is the P-R interval ?

Answer 12

Time from the beginning of the P wave to the start of the QRS complex

Question 13

What is the QRS complex ?

Answer 13

Time from Q deflection to S deflection

Question 14

What is the Q-T interval ?

Answer 14

Time from Q deflection to the end of the T

Question 15

What is R ?

Answer 15

The largest part of the wave

Question 16

What is Q ?

Answer 16

The beginning of the R

Question 17

What does Q represent ?

Answer 17

Depolarisation in the septum

Question 18

What does R represent ?

Answer 18

The electrical stimulus as it passes through the main portion of the ventricular walls

Question 19

What is the S ?

Answer 19

The smallest part of the large waves

Question 20

What does S represent ?

Answer 20

The final depolarisation of the ventricles

Question 21

What is the T-wave ?

Answer 21

Repolarisation of the ventricular myocardium

Question 22

What is blood pressure a measure of ?

Answer 22

Changing fluid pressure within the circulatory system

Question 23

What does blood pressure vary between ?

Answer 23

A peak pressure produced by contraction of the left ventricle, to a low pressure

Question 24

What is low blood pressure maintained by ?

Answer 24

Closure of the aortic valve and elastic recoil of the arterial system

Question 25

What is the pressure peak called ?

Answer 25

Systole

Question 26

What is meant by diastole ?

Answer 26

Pressure that is maintained even while the left ventricle is relaxing

Question 27

Why is mean arterial pressure not a simple average of two pressures ?

Answer 27

The duration of diastole is twice that of systole

Question 28

How is MAP used by emergency room and icu ?

Answer 28

A measure of adequacy of blood supplies to vital tissues when blood pressure is dangerously low

Question 29

What does the cold stimulus activate ?

Answer 29

The sympathetic nervous system resulting in haemodynamic changes that prepare the body for fight or flight response

Question 30

What makes the sensitivity of blood pressure to harmful external or internal injuries useful ?

Answer 30

Its a vital sign, an indicator or health, disease, excitement and stress

Question 31

What does measurement of lung volume provide a tool for ?

Answer 31

Understanding normal function of the lungs as well as diseased states

Question 32

What is the breathing cycle initiated by ?

Answer 32

Expansion of the chest

Question 33

What happens during quite breathing ?

Answer 33

Contraction of the diaphragm muscle causing it to flatten downwards

Question 34

What does the contraction of the diaphragm muscle do ?

Answer 34

Increases the vertical dimension of the thoracic cavity

Question 35

What lifts the ribs ?

Answer 35

External intercostals

Question 36

What do external intercostals do ?

Answer 36

Lift the ribs, expanding the outwards and increase the cavity volume

Question 37

What does the increase in chest volume do ?

Answer 37

Creates a negative pressure and draws air through the nose and mouth

Question 38

What is normal exhalation ?

Answer 38

Passive

Question 39

What does normal exhalation result from ?

Answer 39

Recoil of the chest wall, diaphragm and lung tissue

Question 40

What does active breathing use ?

Answer 40

Accessory respiratory muscles

Question 41

What are some examples of accessory respiratory muscles ?

Answer 41

1. Sternocleidomastoid 2. Scalenes 3. Internal intercostals 4. Abdominal muscle groups

Question 42

What is the function of accessory respiratory muscles ?

Answer 42

To further expand and contract the thorax

Question 43

What is the total lung capacity used at rest in normal breathing ?

Answer 43

1/10 the total lung capacity

Question 44

What is tidal volume ?

Answer 44

The volume of air breathed in and out without conscious effort

Question 45

What is inspiratory reserve volume ?

Answer 45

The additional volume of air that can be inhaled with maximum effort after a normal inspiration

Question 46

What is expiratory reserve volume ?

Answer 46

The additional volume of air that can be forcible exhaled after normal exhalation

Question 47

What is vital capacity ?

Answer 47

The total volume of air that can be inhaled after a maximum exhalation

Question 48

What is the equation for vital capacity ?

Answer 48

Tidal volume + Inspiratory reserve volume + expiratory reserve volume = vital capacity

Question 49

What is residual volume ?

Answer 49

The volume of air remaining in the lungs after maximum exhalation

Question 50

What cannot happen to the lungs ?

Answer 50

They can never be completely emptied

Question 51

What is the equation for total lung capacity ?

Answer 51

Vital capacity + residual volume = total lung capacity

Question 52

What is minute ventilation ?

Answer 52

The volume of air breathed in one minute

Question 53

What is the equation for minute ventilation ?

Answer 53

Tidal volume x breaths per minute