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1
Q

What initiates the electrical conduction system in the heart?

A

The impulse begins in the pacemaker cells in the SAN

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2
Q

What is the sequence of impulse travel in the heart’s conduction system?

A

SAN → Atria → AV Node → Bundle of His → Left and Right Bundle branches → Purkinje Fibres

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3
Q

How is cardiac output calculated?

A

CO = HR x SV

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4
Q

What happens to cardiac output and heart rate during strenuous exercise?

A

Cardiac output increases and heart rate increases

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5
Q

What role do platelets play in blood clotting?

A

Platelets release thromboplastin which converts soluble fibrinogen into insoluble fibrin

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6
Q

List two features of erythrocytes that make them suited for their function.

A
  • Small and flexible to fit through small capillaries
  • Biconcave shape for large SA to volume ratio
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7
Q

Does blood pressure increase or decrease during exercise?

A

Increase

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8
Q

What effect does increased cardiac output have on blood pressure?

A

Increases blood pressure

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9
Q

What are three factors that affect resistance in blood vessels?

A
  • Blood viscosity
  • Blood vessel length
  • Blood vessel radius
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10
Q

Why do obese individuals typically have high blood pressure?

A

They have a longer overall blood vessel length

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11
Q

What effect does a vasoconstrictor drug have on blood pressure?

A

Increases blood pressure

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12
Q

What type of cells line the respiratory tract and what is their function?

A

Ciliated columnar epithelial cells and goblet cells; goblet cells produce mucus to trap particles

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13
Q

What is the role of the diaphragm in breathing?

A

Increases the volume of the thoracic cavity during inspiration

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14
Q

What is the partial pressure of oxygen at an atmospheric pressure of 560 mmHg?

A

117.6 mmHg

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15
Q

What causes oxygen to move from the alveoli to the bloodstream?

A

Differing partial pressures

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16
Q

Which components of blood are retained in the glomerulus?

A

Blood cells and large plasma proteins

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17
Q

What structural feature of the glomerulus ensures suitable blood pressure for filtration?

A

The afferent arteriole is wider than the efferent arteriole

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18
Q

What are the four types of cells in a gastric gland?

A
  • Zymogenic (peptic) cells
  • Parietal (oxyntic) cells
  • Mucus (goblet) cells
  • Enteroendocrine cells
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19
Q

Why is an acidic pH vital in the stomach?

A

To activate the enzyme pepsin and protect against infection

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20
Q

What effect does the destruction of parietal cells have on vitamin B12 uptake?

A

Stops or slows down the uptake of vitamin B12

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21
Q

Name the structures inside the villi of the small intestine that transport products of fat digestion.

A

Lacteals

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22
Q

What type of epithelial cells line the small intestine?

A

Columnar cells with microvilli

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23
Q

What is the function of secretin?

A

Inhibits gastric juice and gastric motility, potentiates CCK action

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24
Q

What hormone stimulates the release of bile from the gall bladder?

A

CCK (cholecystokinin)

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25
Q

What are the three phases of gastric secretion?

A
  • Cephalic phase
  • Gastric phase
  • Intestinal phase
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26
Q

What is required for all living cells concerning materials?

A

Delivery of raw materials (nutrients, oxygen) and removal of waste products (e.g. carbon dioxide)

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27
Q

What are the two transport systems in humans for material exchange?

A

Circulatory system and lymphatic system

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28
Q

What does the circulatory system include?

A

Heart, blood, and blood vessels

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29
Q

Where is the heart located?

A

In the thoracic cavity

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30
Q

What type of muscle is the heart made of?

A

Cardiac muscle

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31
Q

What function does the cardiac muscle perform?

A

Involuntarily contracts to pump blood around the body

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32
Q

What are the three layers of the heart?

A
  • Epicardium
  • Myocardium
  • Endocardium
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33
Q

What is the function of the epicardium?

A

Protects and lubricates the outer section of the heart

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34
Q

What is the myocardium responsible for?

A

Pumping action of the heart

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35
Q

What is the function of the endocardium?

A

Protects valves and chambers, prevents blood sticking (avoiding clot formation)

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36
Q

What surrounds and protects the heart?

A

The pericardium

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37
Q

How many chambers does the heart have?

A

Four chambers

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38
Q

What separates the left and right sides of the heart?

A

Septum

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39
Q

What are the two circuits of blood flow in the heart?

A
  • Pulmonary circuit
  • Systemic circuit
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40
Q

What is the pulmonary circuit responsible for?

A

Pumping blood to the lungs

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41
Q

What is the systemic circuit responsible for?

A

Pumping blood to the rest of the body

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42
Q

What is unique about the myocardium of the left ventricle?

A

It is thicker than the myocardium of the right ventricle

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43
Q

What is the flow of blood in the pulmonary circuit?

A
  • Deoxygenated blood enters right atrium via vena cava
  • Flows to right ventricle
  • Pumped to lungs via pulmonary arteries
  • Oxygenated blood returns to heart
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44
Q

What is the flow of blood in the systemic circuit?

A
  • Oxygenated blood enters left atrium via pulmonary vein
  • Flows to left ventricle
  • Pumped to body via aorta
  • Deoxygenated blood returns to heart
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45
Q

What are the major blood vessels in the circulatory system?

A
  • Pulmonary artery
  • Pulmonary vein
  • Aorta
  • Vena cava
  • Hepatic artery
  • Hepatic vein
  • Mesenteric artery
  • Mesenteric vein
  • Renal artery
  • Renal vein
  • Carotid artery
  • Jugular vein
  • Coronary arteries
  • Coronary vein
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46
Q

What is the role of coronary arteries?

A

Supply nutrients and oxygen to cardiac muscle cells

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47
Q

What is coronary heart disease caused by?

A

Fatty deposits building up in coronary artery walls (atherosclerosis)

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48
Q

What occurs during a myocardial infarction?

A

Blood flow to the heart muscle is reduced or stopped, leading to muscle death

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49
Q

What is the function of heart valves?

A

Ensure that blood flows in the proper direction through the heart

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50
Q

How many valves are in the heart?

A

Four valves

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51
Q

What are the atrioventricular (AV) valves?

A
  • Right AV valve (tricuspid)
  • Left AV valve (mitral/bicuspid)
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52
Q

What do the semilunar valves do?

A

Prevent blood from flowing back into the ventricles

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53
Q

What type of blood do arteries carry?

A

Oxygenated blood, except for the pulmonary artery

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54
Q

What type of blood do veins carry?

A

Deoxygenated blood, except for the pulmonary vein

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55
Q

What is the structure of capillaries?

A

Very thin walls, often only one cell thick, allowing for efficient gas exchange

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56
Q

What is the approximate volume of blood in an adult human?

A

~5L

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57
Q

What is plasma primarily composed of?

A

Water (~91.5%) and proteins (~7%)

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58
Q

What is the function of haemoglobin in red blood cells?

A

Carries oxygen, with each molecule capable of carrying 4 O2 molecules

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59
Q

What is the lifespan of red blood cells?

A

~120 days

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60
Q

What are the main types of white blood cells?

A
  • Granulocytes
  • Monocytes
  • Lymphocytes (T & B cells)
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61
Q

What is the role of platelets?

A

Involved in clotting (haemostasis)

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62
Q

What triggers the coagulation cascade during haemostasis?

A

Release of thromboplastin by aggregated platelets

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63
Q

What is the function of the sinoatrial (SA) node?

A

Acts as the primary pacemaker of the heart, initiating impulses

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64
Q

Where is the atrioventricular (AV) node located?

A

At the base of the right atrium near the septum

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65
Q

What is the role of Purkinje fibers?

A

Conduct impulses throughout the ventricles, causing contraction

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66
Q

What is the impulse travel time from the SA node to the AV node?

A

0.08s

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67
Q

What are non-SA autorhythmic tissues referred to as?

A

Latent pacemakers

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68
Q

What happens if the SA node is damaged?

A

The slower AV node assumes pacemaker activity

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69
Q

Where is the Atrioventricular (AV) node located?

A

At the base of right atrium near septum and just above junction of atria and ventricles

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70
Q

What is the function of the AV node?

A

Receives impulse from SA node and initiates further impulses while delaying conduction

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71
Q

What is the potential action potential generation rate of the AV node?

A

40-60 action potentials/min

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72
Q

What occurs if the AV node is damaged?

A

Complete heart block with atria and ventricles contracting at different rates

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73
Q

What is the pathway of impulses from the AV node?

A

AV node to the bundle of His, which divides into right and left bundle branches

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74
Q

What is the potential action potential generation rate of the Bundle of His?

A

20-40 action potentials/min

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75
Q

What are Purkinje fibres responsible for?

A

Simultaneous contraction of the ventricles

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76
Q

What is the rapid impulse spread duration through ventricles?

A

0.08-0.09s

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77
Q

What is an ectopic focus?

A

When Purkinje fibres become overly excitable and depolarize faster than SA node

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78
Q

What can cause premature action potentials in the heart?

A

Anxiety, lack of sleep, excess caffeine, nicotine, alcohol

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79
Q

What characterizes the action potentials in contractile cardiac muscle cells?

A

Involves rapid depolarization, plateau phase, and repolarization

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80
Q

What occurs during phase 0 of action potential in contractile cells?

A

Opening of voltage-gated Na+ channels causing depolarization

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81
Q

What happens during the plateau phase (phase 1 & 2) of action potential?

A

K+ exits the cell while Ca2+ enters, keeping membrane potential at plateau

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82
Q

What prevents a second action potential from being initiated during the plateau phase?

A

The plateau phase prevents tetany

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83
Q

What is the outcome of phase 3 in cardiac action potential?

A

Ca2+ channels close, K+ channels open, leading to repolarization

84
Q

What is the cardiac cycle?

A

The pattern of contraction (systole) and relaxation (diastole) during one heartbeat

85
Q

What occurs during atrial systole?

A

Both atria contract simultaneously, sending blood into ventricles

86
Q

What happens during ventricular systole?

A

Blood is ejected from both ventricles simultaneously

87
Q

How long does atrial systole last?

A

0.1s (100ms)

88
Q

What occurs during ventricular diastole?

A

Ventricular muscle relaxes, allowing passive filling from atria

89
Q

What causes the ‘lub dub’ sounds of the heartbeat?

A

Closing of the AV and SL valves

90
Q

What are the two regions of the brain involved in nervous control of heart rate?

A
  • Cardioaccelerator region (SNS)
  • Cardioinhibitory region (PSNS)
91
Q

What does the cardioaccelerator region stimulate?

A

Increases heart rate during stress

92
Q

What neurotransmitter is released by sympathetic nerve fibers?

A

Noradrenaline (NE)

93
Q

What is the effect of the cardioinhibitory region?

A

Decreases heart rate by releasing acetylcholine (ACh)

94
Q

What is cardiac output (CO)?

A

Volume of blood pumped out by the heart in a given time period

95
Q

What is the formula for calculating cardiac output?

A

CO = HR X SV

96
Q

What changes occur in the heart due to regular exercise?

A
  • The heart gets larger
  • Muscular wall becomes thicker and stronger
  • Increased stroke volume at rest
97
Q

What two factors affect blood pressure?

A
  • Cardiac output
  • Peripheral resistance
98
Q

What is mean arterial pressure (MAP)?

A

Average arterial pressure throughout one cardiac cycle

99
Q

What is the function of the respiratory system?

A

Allows gaseous exchange between atmosphere and bloodstream

100
Q

What structures comprise the upper respiratory system?

A
  • Nose
  • Pharynx (includes tonsils and adenoid)
101
Q

What structures comprise the lower respiratory system?

A
  • Larynx
  • Trachea
  • Lungs
  • Bronchi/bronchioles
  • Alveoli
102
Q

What is the function of the epiglottis?

A

Prevents food from entering the trachea during swallowing

103
Q

What supports the trachea?

A

C-shaped rings of cartilage

104
Q

What type of cells line the trachea?

A
  • Ciliated columnar epithelial cells
  • Goblet cells
105
Q

What is the function of goblet cells in the trachea?

A

Produce mucus

106
Q

What is the location of the lungs?

A

In the thoracic cavity

107
Q

What is the pleural membrane?

A

Double layer membrane that encloses and protects the lungs

108
Q

What is the role of the pleural fluid?

A

Reduces friction during inhalation and exhalation

109
Q

What is the function of alveoli?

A

Site of gas exchange

110
Q

What do bronchioles eventually form?

111
Q

What type of cells produce surfactant in the alveoli?

A

Type II cells

112
Q

What is the danger associated with asthma attacks?

A

Small bronchioles can be closed off by constriction of smooth muscle

113
Q

What are the two types of epithelial cells in the alveoli?

A

Type I cells (simple squamous) and Type II cells (septal cells)

Type II cells produce surfactant to reduce surface tension in the alveoli.

114
Q

What is the function of surfactant produced by type II cells?

A

Reduces surface tension of mucus lining alveoli

This allows lungs to expand more easily.

115
Q

What condition is caused by insufficient surfactant in premature babies?

A

Respiratory distress syndrome

This condition requires more effort to inflate their lungs.

116
Q

What surrounds the alveoli and facilitates gas exchange?

A

A dense network of blood capillaries

These distribute deoxygenated blood to every alveolus.

117
Q

What is the role of alveolar macrophages?

A

Function as the first line of defence against inhaled pathogens

They are lung resident macrophages.

118
Q

What does Boyle’s law state?

A

The pressure of a gas varies inversely with its volume at constant temperature

This principle is crucial for understanding breathing mechanics.

119
Q

What is Dalton’s law?

A

Total pressure of gases in a mixture is equal to the sum of their partial pressures

This law applies at constant volume and temperature.

120
Q

What is Charles’ law?

A

Volume of gas is directly proportional to its absolute temperature

This law helps explain how temperature affects lung volume.

121
Q

What causes air to flow in and out of the lungs?

A

Pressure differences between the atmosphere and gases inside the lungs

Changes in lung volume create these pressure differences.

122
Q

Which muscles are primarily involved in breathing?

A

Diaphragm and intercostal muscles

The diaphragm lies beneath the lungs, and intercostal muscles are between the ribs.

123
Q

What happens to the diaphragm during inspiration?

A

Diaphragm contracts and flattens

This increases thoracic volume and decreases pressure in the lungs.

124
Q

What occurs during expiration according to Boyle’s law?

A

Diaphragm relaxes, pressure in lungs increases, air is forced out

This is due to the decrease in thoracic volume.

125
Q

Define tidal volume.

A

Volume of air moved into and out of lungs during normal quiet breathing

Normal tidal volume is around 500ml.

126
Q

What is inspiratory reserve volume (IRV)?

A

Max volume of air that can be inhaled after a normal breath

This volume is used when deeper breaths are needed.

127
Q

What is residual volume (RV)?

A

Volume of air remaining in lungs after max exhalation

This volume ensures that the lungs do not collapse.

128
Q

What is total lung capacity (TLC)?

A

Sum of all lung volumes, approximately 6L in an adult

This is a measure of the maximum volume the lungs can hold.

129
Q

What is the primary role of gas exchange in breathing?

A

Brings oxygen needed for cellular respiration and removes CO2

This process is vital for maintaining cellular function.

130
Q

How is oxygen primarily transported in the blood?

A

Mainly bound to haemoglobin (oxyhaemoglobin) in red blood cells

97% of oxygen is transported this way.

131
Q

What dictates the movement of gases in the body?

A

Differences in their partial pressures

Gas will move from areas of high partial pressure to areas of low partial pressure.

132
Q

What does the oxygen dissociation curve illustrate?

A

The relationship between partial pressure of oxygen (pO2) and haemoglobin saturation

High pO2 promotes binding, while low pO2 promotes release.

133
Q

What causes a rightward shift in the oxygen dissociation curve?

A

Decreased affinity of haemoglobin for O2, promoting release

Factors include increased carbon dioxide levels, temperature, and H+ concentration.

134
Q

What is the role of the juxtaglomerular apparatus (JGA)?

A

Involved in maintaining blood pressure and volume

It consists of granular cells that produce renin.

135
Q

What is tubular reabsorption?

A

Process of substances being reabsorbed from tubules back to blood

Most of the filtrate is eventually reabsorbed.

136
Q

What is the primary function of the loop of Henle?

A

Reabsorbs water and sodium chloride from the filtrate

This helps to concentrate urine and conserve water.

137
Q

What hormone regulates the concentration of urine?

A

Anti-diuretic hormone (ADH)

It increases water reabsorption in the kidneys.

138
Q

What is the effect of dehydration on ADH levels?

A

Increased ADH secretion

This results in more water reabsorption and less urine output.

139
Q

What happens during negative feedback in relation to osmotic pressure?

A

Changes in osmotic pressure trigger ADH release or reduction

This regulates water absorption and urine concentration.

140
Q

What is the effect of increased blood water volume on ADH release?

A

Less ADH released from posterior pituitary

This leads to decreased permeability to water in DCT and CD in kidneys.

141
Q

What happens when ADH levels decrease?

A

Decreased water absorption, larger volume of more dilute urine

This helps restore homeostasis.

142
Q

What is the juxtaglomerular apparatus (JGA) involved in?

A

Maintaining blood pressure and volume

143
Q

What do granular cells in the JGA produce?

144
Q

What do macula densa cells detect?

A

Changes in sodium concentration in tubule fluid

145
Q

What triggers the secretion of renin from the JGA?

A

A fall in blood pressure in the afferent arteriole

146
Q

What does renin ultimately increase?

A

Angiotensin II

147
Q

How does angiotensin II increase blood pressure?

A

Stimulates adrenal gland to produce aldosterone

148
Q

What is the effect of aldosterone?

A

Increases Na+ reabsorption by tubules

This leads to increased H2O reabsorption and increased blood volume.

149
Q

What is the normal blood pH range?

150
Q

What can cause detrimental effects to cellular processes?

A

Fluctuations outside the blood pH range of 7.35-7.45

151
Q

What are the mechanisms that regulate blood pH?

A
  • Chemical acid-base buffer systems
  • Respiration
  • The kidneys
152
Q

How do chemoreceptors in the carotid and aortic arteries respond?

A

Detect changes in blood levels of CO2, O2, and H+

153
Q

What happens when there is an increase in CO2 levels?

A

Respiratory centre increases breathing rate to remove CO2 and raise pH

154
Q

What is respiratory acidosis?

A

Develops when lungs do not expel sufficient CO2

155
Q

What can cause respiratory acidosis?

A
  • Asthma attack
  • COPD
  • Pneumonia
  • Slowed breathing
156
Q

What is metabolic acidosis?

A

Develops when the amount of acid in the body increases

157
Q

What can lead to metabolic acidosis?

A
  • Ingestion of acidic substances
  • Poisoning
  • Diarrhoea
  • Renal failure
158
Q

What occurs when pH is above 7.45?

A

Alkalosis develops

159
Q

What is respiratory alkalosis?

A

Develops when there is excessive loss of CO2 from blood

160
Q

What can cause respiratory alkalosis?

A
  • Hyperventilation
  • High altitude
  • Fever
  • Aspirin overdose
161
Q

What is metabolic alkalosis?

A

Develops when the body gains too much base or loses too much acid

162
Q

What is the function of the acid-base buffer system?

A

Neutralises added acid or base to resist changes to pH

163
Q

What are the components of the bicarbonate buffer system?

A
  • CO2
  • Water
  • Carbonic acid (H2CO3)
  • Bicarbonate ions (HCO3-)
  • H+
164
Q

What is the role of the gastrointestinal tract?

A

Digests food into smaller soluble food molecules

165
Q

What does the digestive system consist of?

A
  • Gastrointestinal tract
  • Accessory digestive organs
166
Q

What are the sections of the alimentary canal?

A
  • Mouth
  • Pharynx
  • Oesophagus
  • Stomach
  • Small intestine
  • Large intestine
  • Rectum
  • Anus
167
Q

What are the four main layers of the digestive tract?

A
  • Mucosa
  • Submucosa
  • Muscularis
  • Serosa
168
Q

What is the function of the mucosa?

A

Forms the surface of the lumen and acts as a protective surface

169
Q

What is the role of the muscularis layer?

A

Produces contractions (peristalsis)

170
Q

What occurs in the mouth during digestion?

A

Mechanical breakdown of food by teeth and tongue

171
Q

What enzyme starts breaking down starch in the mouth?

A

Salivary amylase

172
Q

What happens to food in the oesophagus?

A

Food is pushed down by peristalsis

173
Q

What is peristalsis?

A

Contractions that move food through the digestive tract

174
Q

What is chyme?

A

Partially digested food as it leaves the stomach

175
Q

What is produced in the stomach to aid in protein digestion?

176
Q

What are gastric glands responsible for?

A

Digestive gastric secretions

177
Q

What types of cells are found in gastric glands?

A
  • Zymogenic
  • Parietal
  • Mucous
  • Enteroendocrine
178
Q

What happens in the small intestine?

A

Majority of chemical digestion occurs

179
Q

What are the three regions of the small intestine?

A
  • Duodenum
  • Jejunum
  • Ileum
180
Q

What is the function of villi in the small intestine?

A

Increase surface area for nutrient absorption

181
Q

What does each villus contain?

A
  • Blood capillary network
  • A lacteal
182
Q

What is the main function of the large intestine?

A

Water reabsorption and storage of faecal material

183
Q

What are the components of the large intestine?

A
  • Caecum
  • Appendix
  • Ascending colon
  • Transverse colon
  • Descending colon
  • Sigmoid colon
  • Rectum
184
Q

What stimulates the production of HCl in the stomach?

185
Q

What does secretin stimulate?

A

Pancreas to produce bicarbonate

186
Q

What does cholecystokinin (CCK) stimulate?

A
  • Pancreas to produce pancreatic juice
  • Gall bladder to contract
187
Q

What is the role of the pancreas in digestion?

A

Secretes digestive enzymes and hormones

188
Q

What does the liver do with the products of digestion?

A

Metabolises carbohydrates, lipids, proteins

189
Q

What is glycogenesis?

A

Storage of excess glucose as glycogen

190
Q

What is gluconeogenesis?

A

Conversion of certain amino acids and lactic acid to glucose

191
Q

What is the role of bile?

A
  • Emulsifies fats
  • Neutralises acidic chyme
192
Q

What is the hepatopancreatic ampulla?

A

The site where the bile duct and pancreatic duct meet

193
Q

What do enzymes do in digestion?

A

Break down large molecules into smaller ones

194
Q

What are the stages of digestion?

A
  • Cephalic phase
  • Gastric phase
  • Intestinal phase
195
Q

What is the role of enzymes in digestion?

A

Enzymes break down large molecules into smaller ones for entering bloodstream

Examples include: Proteins –> peptides –> amino acids (peptidases/proteases), Triglycerides –> monoglycerides + fatty acids (lipases), Starch –> maltose –> glucose (amylase, maltase), DNA/RNA –> sugar + base + phosphate (DNase)

196
Q

What are the stages of digestion?

A
  1. Cephalic phase 2. Gastric phase 3. Intestinal phase

Each phase has specific triggers and physiological responses.

197
Q

When does the cephalic phase of digestion begin?

A

Before food enters mouth

It is initiated by sight, smell, or thought of food.

198
Q

What stimulates PS impulses during the cephalic phase?

A

Sight, smell, thought of food

These impulses lead to increased gastric secretions and motility.

199
Q

What happens during the gastric phase of digestion?

A

Initiated by stretching of the stomach and presence of food

Chemoreceptors detect increase in pH as food enters the stomach.

200
Q

What does gastrin do during the gastric phase?

A

Causes release of gastric juice

It also stimulates peristalsis.

201
Q

What triggers the intestinal phase of digestion?

A

Fatty acids and glucose in duodenum

This phase involves the release of gastrin, GIP, secretin, and CCK.

202
Q

What is the enterogastric reflex?

A

Reflex initiated by stretching of duodenum

It inhibits PS signals that increase digestion and stimulates sympathetic nerves that suppress gastric activity.

203
Q

What is the effect of the intestinal phase on gastric activity?

A

Reduces gastric activity and rate of stomach emptying

This regulates the rate at which chyme leaves the stomach.

204
Q

Fill in the blank: The cephalic phase is initiated by _______.

A

sight, smell, thought of food

205
Q

True or False: The gastric phase is primarily triggered by the presence of carbohydrates in the stomach.

A

False

It is mainly triggered by proteins.

human body (5 decks)

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