Physiology Flashcards
(178 cards)
1
Q
Define a homeostatic mechanism
A
A regulating mechanism triggered by an alteration in physiological property or quantity, acting to produce a compensatory change in the opposite direction
2
Q
What organ is responsible for the control of thermoregulation
A
Hypothalamus
Controls both heat production (shivering and increased voluntary effort) and heat loss (change to blood flow, sweating)
3
Q
Where are temperature sensitive receptors found
A
Anterior hypothalamus
4
Q
Below what temperature does the temperature regulatory mechanism completely fail
A
<30
5
Q
What ECG changes can be found in hypothermia
A
J waves
6
Q
What occurs with spinal cord injuries in regard to thermoregulation
A
Thermoregulatory mechanism lost below the level of injury
Vasoconstriction is lost therefore heat loss is increased
Patient is unable to shiver
7
Q
What are the two types of diuresis
A
Water diuresis - where there is excess water to the bodies requirement and so water is lost
Osmotic diuresis - where there is more solute than can be absorbed, so it is lost and due to osmosis so is water
8
Q
How is body osmolality controlled
A
Adjustments in the secretion of ADH
Thirst mediated water intake
9
Q
Why do the osmotic receptors indicating thirst have a higher threshold than the osmotic receptors involved in ADH release
A
It ensures that thirst is not experienced until ADH release has ensured that the water ingested is retained by the kidneys
10
Q
Where is most of the filtered sodium in the kidney reabsorbed
A
65% proximal tubule
25% loop of Henle
11
Q
What are the two important intrarenal affects of Angiotensin II
A
Stimulates sodium reabsorption in most nephron segments
Constricts the glomerular arterioles
12
Q
Other than increased osmolality what can stimulate thirst and ADH release
A
Reduced arterial blood pressure - signals via carotid and aortic baroceptors
Reduced central venous pressure - signals via martial low pressure receptors
Increased angiotensin II in the brain
13
Q
What is ANP released in response to
A
Released from the cardiac atria in response to stretch
14
Q
Briefly outline RAAS
A
Renin, Angiotensin Aldosterone System
Renin released from the juxtaglomerular apparatus in response to reduced sodium, reduced perfusion pressure, direct sympathetic stimulation
Angiotensin I produced, cleaved to produce Angiotensin II - net effect of this is to increase TPR and BP
Stimulates hypothalamus - thirst reflex and posterior pituitary - ADH release
Angiotensin II acts on adrenal cortex to release Aldosterone
Aldosterone acts on the principal cells of the collecting ducts of the nephrons
15
Q
How does ANP increase the secretion of Na
A
Increases GFR
Inhibits sodium reabsorption on collecting ducts
Reduces the secretion of aldosterone and renin
16
Q
Causes of hypernatraemia
A
Water depletion - reduced intake, diuretic stage of AKI, diabetes insipidus
Sodium excess - XS sodium therapy, Conn’s syndrome, Cushing’s syndrome, Steroid, CCF, Cirrhosis
17
Q
Causes of hyperkalaemia
A
Renal failure
Haemolysis
Crush injuries
Tissue necrosis
Metabolic acidosis
Adrenal insufficiency
18
Q
Causes of hypokalaemia
A
Reduced oral intake
Renal - diuretics, renal tubular disorders
GI - D+V, fistula, laxatives, villous adenoma
Endocrine - Cushing’s, steroids, hyperaldosternoism (Conns)
19
Q
What are the causes of respiratory acidosis
A
CNS depression - head injury, drugs coma, CVA, encephalitis
Neuromuscular disease - Myasthenia graves, GBS
Skeletal disease - Kyphosis, Ank Spon, Flail chest
Artificial ventialtion
Impaired gaseous exchange - thoracic injury, obstructive airway disease, alveolar disease
20
Q
What are the causes of respiratory alkalosis
A
Stimulation of respiratory centre - high altitude, pneumonia, pulmonary oedema, PE, feel, head injury
Increased alveolar gas exchange - hyperventilation, artificial ventilation
21
Q
What are the causes of metabolic acidosis
A
DKA
Lactic acidosis
Septicaemia
Starvation
Renal failure
Diarrhoea
Intestinal, biliary and pancreatic fistulae
22
Q
What are the causes of a metabolic alkalosis
A
Vomiting
Nasogastric aspiration
Gastric fistula
Diuretic therapy
Cushing’s syndrome
Conn’s syndrome
23
Q
What is the normal anion gap
A
Between 10-19 mmol/LH
24
Q
How is the anion gap calculated
A
(Na+ + K+) - (HCO3 - + CL - )
25
What hormones are increased following trauma/surgery
ADH
Catecholamines
Cortisol
Aldosterone
26
What is the starling equilibrium
Capillary hydrostatic pressure + tissue oncotic pressure = interstitial fluid pressure + plasma oncotic pressure
27
What are the causes of oedema
Increased capillary hydrostatic pressure - CCF, venous obstruction, increased fluid volume
Decreased plasma oncotic pressure due to hypoproteinaemia - starvation, cirrhosis, nephrotic syndrome
Increased capillary permeability - inflammatory reactions, allergic reactions
28
Describe the mechanics of pulmonary ventilation
At the beginning of inspiration intrapleural pressure is around -4cmH20
Contraction of the respiratory muscles increases the volume of the chest - this decreases the intrapleural pressure to around -9cmH20
The change in intrapleural pressure causes the lungs to expand and thus generate a negative intra-alveolar pressure as the alveoli are pulled open
As the atmospheric pressure is higher air flows from the high pressure to the low pressure.
29
What is the function of accessory muscles during exercise
They can generate more intreapleural pressures - which allow inhalation of 2-3L of air
30
Is inspiration or expiration a passive process
Expiration - passive process due to the recoil of the chest wall
31
What are the three forces acting on the lung
Elastic nature of the lungs - under normal conditions the lungs are stretched
Surfactant - lines the alveoli and exerts inwards or collapsing pressure
Negative intrapleural pressure - oppose the above two forces. Negative pressure is created by the chest wall and diaphragm pulling the parietal pleura outwards. As the two layers of pleural are pulled in opposite directions they generate a negative pressure
32
What is the function of surfactant
Lowers surface tension, increased compliance and reduced the work of breathing
Prevents fluid accumulating in the alveoli
Reduces the tendency of alveoli to collapse
33
What is alveolar instability
The tendency of alveoli collapsing
34
What two factors govern compliance of breathing
Elasticity of the lung parenchyma
Surface tension
35
What decreases lung compliance
scarring/fibrosis of lung parenchyma
pulmonary oedema
deficiency of surfactant
36
What is work of breathing
The work required to move the lung and chest wall
37
Define tidal volume
The total amount of air taken in and exhaled during quiet breathing
38
Define inspiratory reserve volume
The maximum volume of air that can be inspired in excess of normal inspiration
39
Define expiratory reserve volume
The maximum amount of air that can be forcefully expired after normal expiration
40
Define functional residual capacity
The volume of gas left in the lungs after expiration during normal breathing
41
Define residual volume
The volume remaining after maximal expiration - it cannot be measured directly (RV = FRC - ERV)
42
Define total lung capacity
The sum of all lung volumes plus residual volume
43
Define vital capacity
The volume of air that is expelled from maximal inspiration to maximal expiration
44
How can FRC be determined
By the helium dilution method
45
What is dead space in regard to ventilation
The volume of air which has been ventilated but does not actually take part in gas exchange
Can be anatomical - the volume of gas that does not mix with the air in the alveoli
Physiological - the volume of gas that may reach the alveoli, but due to lack of perfusion does not take place in gas exchange
46
What is diffusion capacity
A test which reflects the diffusion capacity of the alveolar membrane and the pulmonary vasculature
Diffusion capacity is reduced with increased diffusion distance, loss of alveolar area
47
What determines blood flow in the lungs
Hydrostatic pressure in the pulmonary arteries
Pressure in the pulmonary veins
Pressure of air in the alveoli
48
What are the physiological changes associated with a pulmonary embolism
Increased pulmonary vascular resistance
Pulmonary HTN
Increased right ventricle afterload, leading to RV dilatation and dysfunction
Reduced left ventricle output
Impaired gas exchange, due to shunting of blood through non-perfused segments of lung
Decreased lung compliance, due to bleeding and loss of surfactant over the area affected
49
What are the stages of pulmonary oedema
Interstitial oedema
Alveolar oedema
Airway oedema
50
What is the physiological effects of pulmonary oedema
Decreased lung compliance due to the reduction in surface tension and alveolar shrinkage
Increased airway resistance - this can occur due to the reduction in lung volume and fluid filling the airways. Resistance is due to bronchoconstriction
51
What are the causes of pulmonary oedema
Raised pulmonary hydrostatic pressure - 2y to left ventricular failure
Increased pulmonary capillary permeability
Blocked lymphatic drainage
High altitude
Neurogenic
52
What are the direct and indirect causes of ARDs
Direct - contusion, near drawing, aspiration, smoke inhalation
Indirect - Trauma, sepsis, pancreatitis
53
What is the criteria for ARDs
Known cause
Acute onset of symptoms
Hypoxia refractory to oxygen
New, bilateral, fluffy infiltrates on CXR
No evidence of cardiac failure (pulmonary artery wedge pressure <18mmHg)
54
What are the two phases of ARDS
Acute exudative
Late organisation
55
What are the three factors affect the diffusion of gases
Pressure gradient
Diffusion coefficient
Tissue factor
56
What does the oxygen dissociation curve show
The relationship between the partial pressure of oxygen and the concentration of oxygen in the blood
57
If the oxygen dissociation curve shifts to the right what happens
There is decreased oxygen affinity, and therefore increased oxygen unloading to tissues
58
What causes the oxygen dissociation curve to shift to the right
Increased hydrogen ions
Increased temperature
Increased 2,3 DPG
Increased carbon dioxide
59
If the oxygen dissociation curve shifts to the left what happens
There is increased oxygen affinity, and therefore decreased oxygen unloading to tissues
60
What causes the oxygen dissociation curve to shift to the left
Decreased hydrogen ions
Decreased temperature
Decreased 2,3 DPG
Decreased carbon dioxide
61
What is the function of myoglobin
Provide additional oxygen in muscles during periods of anaerobic respiration
62
What is the Bohr effect
Shifting of the oxygen dissociation curve to the right
Represents a method to increased oxygen extraction
63
What is the Haldane effect
The amount of carbon dioxide carried increased as the oxygen level falls
64
Where is the respiratory centre found and what two types of neuroses are found there
Medulla Oblongata
Inspiratory neurones - demonstrate rhythmical firings potentials with intervening periods of inactivity. The action potentials stimulate the diaphragm and external intercostals to contract
Expiratory neurones - inactive during quiet respiration. During periods of exercise or increased respiration - they fire action potentials which cause the internal intercostals and abdominal wall muscles to contract
65
What is the function of the apneustic centre
Prolongs inspiration and results in short expiratory efforts
66
What is the function of the Pneumotaxic centre
Inhibits inspiratory neurones and shortens respiration
67
Which chemoreceptors are the main determinant of respiration and what are they sensitive to
Central chemoreceptors in the medulla
Sensitive to changes in CO2
68
Where are peripheral chemoreceptors found and what do they respond to
In the carotid bodies, close to the bifurcation of the common carotids and in the aortic bodies
Respond to arterial pH and low levels of pO2
69
What is the pathogenesis of hypoxic drive
In severe long-standing lung disease with persistently elevated carbon dioxide patients will become accustomed to this and lose the controlling effect of P CO2
Therefore the low levels of oxygen (detected by peripheral chemoreceptors) are relied on to stimulate respiration
70
Define hypoxia
A deficiency of oxygen in the tissues
71
Define hypoxaemia
Reduction in the concentration of oxygen in the arterial blood
72
What causes hypoxic hypoxia and give conditions in which this would be expected
Results from low arterial pO2
Causes: high altitude, PE, hypoventilation, lung fibrosis, pulmonary oedema
73
What causes anaemic hypoxia
A decreased in the amount of haemoglobin and therefore a decrease in oxygen content of arterial blood
74
What is histotoxic hypoxia
Poisoning of the enzymes involved in cellular respiration, oxygen is available but cannot be utilised.
Occurs in cyanide poisoning
75
What are the causes of hypoxaemia
Hypoventilation
Impaired diffusion
Shunt
Ventilation and perfusion inequality
Reduction in inspired oxygen tension
76
Describe type I respiratory failure
Hypoxaemic respiratory failure
PaCO2 <6 kPA
Due to ventilation perfusion mismatching
Causes: Pneumothorax, pneumonia, contusion, PE, ARDS
77
Describe type II respiratory failure
Ventilatory failure
Due to the inadequate movement of air
Causes: COPD, neuromuscular disorders, airway obstruction, central respiratory depression, chest wall deformity
78
What are the indications for ventilation
Inadequate ventilation - apnoea, RR >35, PaCO2 >8kPa
Inadequate oxygenation - PaO2 <8kPa with 60% oxygen
Surgical indications - head injury, chest injury, facial trauma, high spinal injury
79
What are some complications of mechanical ventilation
Ventilator induced injury
Volutrauma
Barotrauma
Hypotension and reduced CO - decreased venous return due to positive intrathoracic pressure
Respiratory muscle atrophy
Nosocomial infections
Increased ICP
80
What actviates the actin myosin complex and allows contraction
Calcium
81
What is the most important factor in controlling myocardial contractility
Increased intracellular calcium increases the force of myocardial contraction
Decreased intracellular calcium decreases the force of myocardial contraction
82
Why is conduction through the AV node slow
To delay transmission from atria to ventricles, ensuring that atrial contraction is finished before ventricular contraction begins
83
Why does atropine not have any effect on a transplanted heart
Because the heart has no vagal innervation
84
What happens in systole
Contraction
Mitral and triscupid valves close
Ejection - aortic and pulmonary valves open
85
What happens in diastole
Relaxation
Aortic and pulmonary valves close
Filling - mitral and tricuspid valves open
86
How is ejection fraction calculated
Stroke volume / Left ventricular end diastolic volume
87
What cause the first and second heart sound
First - due to closure of the AV valves
Second - due to the closure of the aortic and pulmonary valves
88
What is coronary blood flow at rest
250mL/min
89
What can coronary blood flow increase to during exercise
up to 1L/min
90
During which phase of the cardiac cycle does coronary blood flow occur
Diastole
91
How is cardiac output calculated
CO = stroke volume x heart rate
92
What is Starling's Law
The energy contraction of a cardiac muscle fibre is a function of the initial length of the muscle fibre
The greater the stretch of the ventricle in diastole, the greater the stroke volume
Up to a point increasing the venous return will increase the force that the heart muscle can exert
93
What factors modify heart rate
Intrinsic rhythmicity
Extrinsic factors - Sympathetic stimulation increases rate and force
Parasympathetic stimulation decreased rate
94
What factors modify stroke volume
Contractility
Preload
Afterload
95
What reduces contractility
Reduced filling
Hypoxia
Hypercapnia
Acidosis
Ischaemia and cardiac disease
PSNS
Electrolyte imbalances
Drugs
96
How is blood pressure calculated
BP = CO x SVR
97
What does systolic and diastolic blood pressure reflect
Systolic - the maximum pressure recorded during systole
Diastolic - the minimum pressure recorded during diastole
98
How is pulse pressure calculated
Systolic pressure - diastolic pressure
99
How is mean arterial pressure calculated
Diastolic pressure + 1/3 of the pulse pressure
100
What type of receptors monitor blood pressure
Baroreceptors
They are stretched with increased BP, causing reflex reduction in vasoconstriction, which with a reduction heart rate leads to reduced SVR and CO and therefore BP
The opposite happens with low BP
101
What is a normal central venous pressure
5-12mmHg
102
What does a low central venous pressure indicate
Hypovolaemia
103
When is adrenaline used as a vasopressor
In septic shock when hypotension due to peripheral vasodilation persists despite adequate volume replacement
104
Dobutamine is used in which kind of shock
Cardiogenic shock
Its beta -1 effect increased the heart rate and the force of contraction
First choice ionotrope in cardiogenic shock due to LVSD
105
Where is the myenteric plexus found and what is it also known as
Found between the circular and longitudinal layers of the GI tract
It is a mainly motor function
Also known as Auerbach's plexus
106
Where is the submucosal plexus found and what is it also know as
Lies within the submucosa
Mainly sensory function
Also known as Meissners plexus
107
What anatomical features of the oesophageal sphincter help it maintain its integrity
Right crus of the diaphragm compresses the oesophagus as it passes through the oesophageal hiatus
The acute angle in which the oesophagus enters the stomach acts as a valve
Mucosal folds at the end of the diaphragm act as a valve
108
Hydrochloric acid is secreted from what cells
Parietal cells
Oxyntic cells
109
What protects the stomach from digestion
Mucus secretion - mucus is alkaline and so helps to neutralise gastric acid
Tight epithelial junctions prevent acid reaching deeper tissues
Prostaglandin E secretion has a protective role - increased mucus layer thickness, stimulates HCO3 production, increases blood flow to the area
110
What are the three phases of gastric secretion
Cephalic - 30% gastrin secretion, stimulates acid and Pepsin secretion, histamine secretion from mast clels
Gastric - 60% distension of stomach and chemical composition of food leads to ACh release
Intestinal - 5% stimulated by presence of food in the duodenum
111
What inhibits gastrin secretion
pH fall to 2-3
Somatostatin
Secretin
Fatty foods - lead to the release of CCK and GIP
112
What are the three muscular layers of the stomach
Longitudinal
Circular
Oblique
113
Describe the physiology of vomiting
Respiration is inhibited
The larynx closes and the soft palate rises
Stomach and pyloric sphincter relax and the duodenum contracts, propelling intestinal contents into the stomach
Diaphragm and abdominal wall contracts and intragastric pressure rises
Gastro-oesophageal sphincter relaxes and the pylorus closes
114
What is the plicae circulares and what is its advantage
The circular folds in the small intestine
Cause the chyme to to spiral round and therefore increase the time taken for absorption to take place
115
Where are crypts of Lieberkuhn found
In the small intestine amongst the vili
116
What do D cells produce
Somatostatin
117
What do S cells produce
Secretin
118
What to N cells produce
Neurotensin
119
What do enterochromaffin cells produce
5-hydroxy-tryptamine
120
In which part of the intestines are Brunner's glands found
Duodenum
121
What are the fat soluble vitamins
Vitamin A, D, E and K
122
What are the water soluble vitamins
Vitamin C and B
123
What is the site of bile salt reabsorption
Terminal ileum
124
Why does a terminal ileum resection lead to a vitamin B12 deficiency
Receptor mediated reabsorption in conjunction with intrinsic factor occurs in the terminal ileum, this will result in deficiency of vitamin B12
125
In what form are enzymes secreted by the pancreas
Proteolytic enzymes and lipolytic enzymes are secreted as pro-enzymes and require activation. The majority of them are activated by trypsin
126
Which two hormones are responsible for stimulating pancreatic secretions
Cholecystokinin (CCK)
Secretin
127
Post pancreateatectomy what physiological abnormalities remain
Malnutrition - inadequate digestion of protein and lipids due to loss of proteolytic and lipolytic enzymes. Absorption of fat soluble vitamins (Vit A D E K )is reduced
Loss of alkaline pancreatic secretions - reduced neutralsation of chyme and therefore loss of iron, calcium and phosphate absorption
128
What are bile pigments produced by
The breakdown of haem unit of haemoglobin
129
Describe enterohepatic circulation
90% of secreted bile acids are reabsorbed from the intestine and returned to the liver by the portal vein, the remaining are altered by bacterial flora and become insoluble and are therefore excreted.
130
What controls the release of bile from the bile duct into the duodenum
CCK stimulates the GB to contract and release bile into the duodenum
131
Summarise bilirubin metabolism
RBC are broken down in the spleen and release bilirubin, a breakdown product of the porphyrin ring of haemoglobin. Bilirubin is unconjugated at this point.
Unconjugated bilirubin is not water soluble and binds to albumin, in the liver the bilirubin is conjugated to glucuronide. This is then conjugated bilirubin.
Bilirubin is converted to urobilinogen in the bowel.
132
Prehepatic causes of jaundice
Inherited - red cell membrane defects, haemoglobin abnormalities, metabolic defects.
Acquired - Immune, mechanical, acquired membrane defects, infections, drugs, burn
133
In summary what causes of preheptaic jaundice
Disorders that result in excessive destruction of RBCs
134
What are the causes of hepatic jaundice
Viruses - hepatitis A,B, C and E and EBV,
Autoimmune disorders - chronic hepatitis
Drugs - POD
Cirrhosis
Liver tumours/Mets
135
In summary what causes of choelstatic jaundice
Obstruction of biliary system
136
Which anal sphincter is under involuntary control
Internal sphincter
137
Which anal sphincter is under voluntary control
External sphincter
138
Describe the reflex arc of defecation
Rectal distension - when faecal material enters the rectum and causes distension, impulses from stretch receptors fire
Conscious awareness - as a result of rectal distension there is activation of receptors which allows differentiation between faeces and flatus. External spinchter contracts
Parasympathetic impulse - increase in tone of colon and relaxation of the external sphincter
Depending on the convenience of defecation at that point the external sphincter either relaxes or contract
139
Describe the microscopic features of the glomerulus which allows filtration
Capillary endothelium is fenestrated - permitting free passage of water and electrolytes
Negatively charged glycopretoiens
Podocytes with foot processes through which filtration can occur
140
What do the actions of ADH include
Increased water permeability of the distal tubule and collecting ducts
Increased arterial blood pressure by vasoconstriction
Secretion of ADH leads to the production of concentrated low volume urine
141
What are juxtaglomerular cells and what do they secrete
Specialised smooth muscle cells that lie in the wall of the afferent arteriole and secrete renin
142
What stimulates the release of renin
Decreased in afferent arteriole pressure
Reduction in sodium, detected by the macula dense which monitors sodium load in the distal tubule
Stimulation by renal sympathetic nerves
143
What are the actions of angiotensin II
Stimulates arterial vasoconstriction
Stimulates the release of ADH
Stimulates drinking
Stimulates the release of aldosterone
144
What are the actions of ANP
Increases glomerular filtration
Inhibits the reabsorption of sodium
145
What is ANP released in response to
In response to an increased volume - via the atrial stretch receptors
146
What volume of urine is in the bladder before there is a desire to micturate
200-300mL
147
Describe the parasympathetic nervous system in urination
Increase detrusor muscle contraction, and decreasing the contraction of the internal sphincter
148
In what injury is an atonic bladder found
Following a spinal injury in spinal shock
149
What is the function of erythropoietin and where is it produced from
Action - accelerates the differentiation of marrow stem cells into erythrocytes
Mainly secreted in the Kidney, but also from the spleen
150
1 alpha hydroxyls catalyse what reaction
25-hydroxycholecalciferol to 1,25- hydroxycholecalciferol
151
What hormones are produced from the anterior pituitary
Adrenocorticotrophic hormone (ACTH)
Thyroid stimulating hormone (TSH)
Follicule stimulating hormone (FSH)
Lutenizing hormone (LH)
Prolactin
Growth hormone
152
What hormones are produced from the posterior pituitary
Oxytocin
Antidiuretic hormone
153
What are the symptoms of a prolactinoma
Galactorrhoea
Amenorrhoea
Impotence
Headaches
Visual field defects
154
What does increase ADH lead to and what are the features
Syndrome of inappropriate antidiuretic hormone
Hyponatraemia, decreased plasma osmolality, increased urine osmolality, urinary sodium >30
155
What are the causes of pituitary deficiency
Rare congenital deficiency - Kallman's syndrome (LH and FSH deficiency)
Infection - meningitis/encephalitis
Pituitary apoplexy
Sheehans syndrome
Cerebral tumours
Radiation
Trauma
Sarcoidosis
156
What is pituitary apoplexy
Pituitary deficiency following bleeding into the pituitary gland
157
What is Sheehan's Syndrome
Pituitary deficiency cause by infarction of the pituitary following postpartum haemorrhage
158
Which cells secrete calcitonin
Parafollicular cells
159
Thyrotrophin releasing hormone is released from where
Hypothalamus
160
Describe the production of thyroid hormones
Hypothalamus secretes thyrotrophin releasing hormone, this then stimulates the release of thyroid stimulating hormone.
TSH stimulates the production of T3 and T4 - these then have a negative feedback on TRH and TSH
161
What are the causes of primary hyperthryoidism
Graves disease
Solitary toxic adenoma/nodule
Toxic multinodular goitre
Acute phase of thyroiditis
Drugs - Amiodarone
162
What are the causes of secondary hyperthryoidism
Pituitary/hypothalamic tumour
Metastatic c thyroid carcinoma
Choriocarcinoma
Ovarian teratoma
163
What are the cause of primary hypothyroidism
Autoimmune
Hashimoto's thyroiditis
Iodine deficiency
Genetic defects
Iatrogenic - post thyroidectomy/radiotherapy
Drugs - lithium
Neoplasia
164
What is chovsteks sign
Twitching of muscles supplied by the facial nerve due to decreased calcium
165
What is Troussea's sign
The sign is observable as a carpopedal spasm induced by ischemia secondary to the inflation of a sphygmomanometer cuff,
166
What are the causes of hypocalcaemia
Hypoalbuminaemia
Hypomagnesaemia
Hypophosphataemia
Hypoparathryodism
Acute pancreatitis
Massive transfusion
Post thyroid surgery
Vitamin D deficiency
Drugs
Hypoventilation
167
What are the causes of hypercalcaemia
Excess PTH
Excess vitamin D
Milk -alkali syndrome
Malignancy
Drugs
168
Why is measuring phosphate in ventilated patients important
Acute hypophosphataemia can lead to significant diaphragmatic weakness and delay weaning from a ventilator in patients in the intensive care unit.
169
What are the three sections of the adrenal cortex
Zona glomerulosa
Zona fasciculata
Zona reticularis
170
What is secreted from the zona glomerulosa
Mineralcorticoids
171
What is secreted from the Zona fasciculata
Glucocorticoids
172
What is secreted from the Zona reticularis
Sex steroids
173
What are the cause of hypophosphataemia
Hyperparathyroidism
Vitamin D deficiency
TPN
DKA
Acute liver failure
Paracetamol overdose
174
What is produced from the adrenal medulla
Adrenaline
Noradrenaline
Dopamine
Beta-hydroxylase
ATP
Opioid peptides
175
Give an example of a Mineralcorticoid
Aldosterone
176
Give an example of a glucocorticoid
Cortisol
Hydrocortisone
177
Describe the anti-inflammatory and immunosuppressive action of glucocorticoids
Decreased the number of immunocompetent cells and macrophages
Reduces teh number to T cells and their function
Reduction B cell clonal expansion
Reduces basophils and eosinophils
Inhibits the compliment pathway
178
