Phase 1 ILAs Flashcards
1
Q
What does SNP stand for? (genetics)
A
Single nucleotide polymorphism
2
Q
What is a SNP?
A
DNA sequence variation when a single nucleotide differs between people
3
Q
What affect can SNPs have?
A
Can change codon, which can change protein, can create disease e.g. sickle cell/cystic fibrosis
4
Q
What is primary protein structure?
A
Chain of amino acids joined by covalent bonds
5
Q
What is secondary protein structure?
A
Alpha helices, beta pleated sheets, H+ bonds
6
Q
What is tertiary protein structure?
A
3D structure of an a.a. chain, can have VdW, H+ bonds, ionic, disulfide bridges, electrostatic attraction
7
Q
What is quaternary protein structure?
A
Several a.a. chains joined together-3D structure of a polypeptide
8
Q
What are the subunits of haemoglobin?
A
2 alpha, 2 beta
9
Q
Normal adult haemoglobin is HbA, what does it change to in sickle cell anaemia?
A
HbS
10
Q
What codon change happens in sickle cell + on what nucleotide?
A
GAG to GTG on 17th nucleotide
11
Q
Is sickle cell dominant or recessive?
A
Autosomal recessive
12
Q
If one, or both parents have sickle cell, what is the chance their offspring will also have the condition?
A
2 parents-1/4 chance offspring has sickle cell
1 parent-50/50 chance of offspring being carrier
13
Q
Name 4 functional changes for someone living with sickle cell
A
Lower O2 affinity
Shorter erythrocyte lifetime
Erythrocytes can get stuck in blood vessels
Reduced delivery of O2 to muscles
14
Q
What is the first stage of protein synthesis?
A
Transcription
15
Q
What happens in transcription?
A
- DNA supercoil unwound by topoisomerase
- DNA helicase breaks H+ bonds + exposes nucleotides
- Single stranded binding proteins stop DNA strands reannealing
- RNA polymerase binds at TATA promoter region, moves in a 3’ to 5’ direction
- RNA polymerase adds nucleotides until stop codon is reached-producing mRNA strand
16
Q
What happens in splicing?
A
Introns are removed
17
Q
What are introns?
A
Non-coding DNA segments
18
Q
What happens in translation?
A
- mRNA binds to ribosome
- tRNA, carrying an amino acid, binds to ribosome
- tRNA anticodon binds to complementary mRNA
- Peptide bond forms between adjacent amino acids
- Polypeptide chain is formed when stop codon is reached
19
Q
What are the 3 stages of translation?
A
Initiation, elongation, termination
20
Q
Where are osmoreceptors located?
A
Hypothalamus
21
Q
What do osmoreceptors do?
A
Detect low blood water potential, causing stimulation of hypothalamus nerve cells + triggering the release of ADH from the pituitary
22
Q
What does ADH act on + what does it do?
A
Acts on kidneys + increases fluid retention
23
Q
Where is albumin produced?
A
Liver
24
Q
How does albumin contribute to oncotic pressure?
A
Helps maintain concentration gradient + create oncotic pressure
25
What is insensible water loss?
Total amount of fluid lost daily from the lungs, skin, respiratory tract + faeces-40-800 ml in an adult
26
What does insufficient H2O in the body do to blood volume?
Decreases blood volume
27
What does insufficient H2O in the body do to blood osmolality?
Increases blood osmolality
28
What is the pathway for response to dehydration?
1. Insufficient H2O in blood causes decrease in blood volume
2. Decreases blood pressure
3. Increases angiotensin II
4. Stimulates thirst centre in hypothalamus
5. Increases thirst
6. H2O taken in
7. Blood osmalality decreases
29
In an average 70kg male what is the total body water?
42L-60% of body weight
30
In an average 70kg male what is the ratio of ICF to ECF?
65:35, 28L:14L
31
In an average 70kg male how much interstitial fluid is there?
11L
32
In an average 70kg male how much plasma fluid is there?
3L
33
How is sodium contained in the body?
70%=exchangeable
30%=stored in bone crystal
ECF contains 50%, ICF contains 5%
34
What reaction does renin catalyse?
Angiotensinogen-->Angiotensin I
35
Which enzyme catalyses the reaction from angiotensin I to angiotensin II?
ACE
36
What does angiotensin cause?
Thirst
Vasoconstriction
Na+ reabsorption
37
What does aldosterone cause?
Na+ reabsorption
K+ excretion
Water retention
38
What activates renin?
Low blood pressure
39
What inhibits renin?
Angiotensin II
Vasopressin
ANF (atrial natriuretic factor)
40
How do you calculate cardiac output?
CO=HR x SV
41
What factors affect heart rate?
Autonomic innervation
Hormones
Fitness levels
Age
42
How do you calculate stroke volume?
SV= EDV (end diastolic volume) - ESV (end systolic volume)
43
What factors affect stroke volume?
Contractility
Preload
Afterload
Heart size
Fitness level
Gender
Duration of contraction
44
Define preload
Degree of myocardial distension prior to shortening
45
Define afterload
Force against which ventricles must act in order to eject blood
46
What areas does the LAD supply?
Anterior 2/3 of interventricular septum
Lateral wall of left ventricles
Anterolateral papillary muscle
47
What can occlusion of LAD cause?
Left/right heart block-when the impulse contraction between atria + ventricles is blocked
48
What areas does the RCA supply?
SAN + AVN
49
What can occlusion of the RCA cause?
Affects nodes, irregular rhythm of contraction, inefficient blood flow + potential backflow
50
How do you calculate blood pressure?
BP=CO x TPR (total peripheral resistance-amount of force exerted on circulating blood by the vasculature of the body)
51
What affects blood pressure?
Vasopressin, Aldosterone, ANP, Haemorrhage, Sweating, Stressors, Hydration, Weight, Muscular activity, Posture
52
How do you calculate pulse pressure?
PP=SP (systolic pressure) - DP (diastolic pressure)
53
How do you calculate mean arterial pressure?
MAP=DP (diastolic pressure) + 1/3PP (pulse pressure)
54
What does the Frank-Starling relationship show?
The effects of heart failure on stroke volume + ventricular preload
55
What causes the 'lub' sound?
Closing of AV valve
56
What causes the 'dub' sound?
Closing of the semilunar valves
57
Where is the greatest resistance to flow in the airways?
Segmental bronchi
58
How do the pleural layers contribute to ventilation?
1. Respiratory muscles expand cavity which creates negative pressure in pleural cavity
2. Visceral pleura pulls on the lungs + decreases the pressure
3. Air rushes into the lungs to equalise the pressure = inspiration
4. Expiration-the intrathoracic pressure increases, forcing the air out
59
What is the function of saliva?
Releases enzymes, antibacterial, pH control, taste, lubrication
60
What does the palate do?
Tongue presses food against it to aid in digestion
61
What nerves supply the oesophagus?
Upper 1/3 is supplied by the superior laryngeal + recurrent laryngeal nerve
Lower 2/3 is supplied by the enteric nervous system
62
What is a common cause of GORD?
Weak oesophageal sphincter-means less pressure is required for fluid to move back up, can be dependent on body position
63
What do mucous cells produce?
HCO3- + mucous-acts as a protective lining + buffer against HCl
64
What hormone's release is triggered by food in the stomach?
Gastrin
65
Name the 9 regions of the abdomen
Right hypochondriac, epigastric, left hypochondriac, right lumbar, umbilicus, left lumbar, right iliac, suprapubic, left iliac
66
What is haematopoiesis?
The formation of blood cellular components
67
Where are erythrocytes produced?
Haemopoietic bone marrow
68
What are reticulocytes?
Immature RBC
69
How long do erythrocytes circulate in the blood for?
120 days
70
Where are old erythrocytes phagocytosed?
Bone marrow, liver + spleen
71
What happens to the haem part of haemoglobin when it is broken down?
Broken into biliverdin for transport in blood. Iron ions bind to blood protein transferrin for transport. Unused haem groups can be used for haempoeisis or converted into bilirubin + used to make bile. Iron ions can be transferred into ferritin for storage in liver
72
What happens to the globin part of haemoglobin when it is broken down?
Metabolised into a.a. + reused for protein synthesis
73
What are the 3 classes of jaundice?
Pre-hepatic, hepatic + obstructive
74
What is pre-hepatic jaundice, what kind of bilirubin does it produce?
When there is excessive RBC breakdown which overwhelms the livers ability to conjugate bilirubin. Produces unconjugated bilirubin
75
What is hepatic jaundice, what kind of bilirubin does it produce?
Dysfunction of the hepatic cells causes the liver to lose the ability to conjugate bilirubin. Produces both conjugated + unconjugated bilirubin
76
What is post-hepatic jaundice, what kind of bilirubin does it produce?
Occurs when there is an obstruction of biliary drainage so bile can't be excreted. Bile is conjugated though as the issue is with removal, not conjugation.
77
What causes pre-hepatic jaundice?
Haemoglobinopathies, abnormal RBC, antibodies, drugs + toxins, thalassaemia
78
What causes hepatic jaundice?
Hepatitis, Gilbert's syndrome, Crigler-Najjar syndrome
79
What causes post-hepatic jaundice?
Gallstones, bile duct tumours, pancreatic/ampulla carcinomas
80
What region of the brain is supplied by the anterior cerebral artery?
Corpus callosum, medial region
81
What region of the brain is supplied by the middle cerebral artery?
Lateral parts of each hemisphere + anterior deep structures
82
What region of the brain is supplied by the posterior cerebral artery?
Posterior region + posterior inferior
83
What does the frontal lobe do?
Contains motor cortices + association areas, prefrontal association area (controls behaviour + decision-making) + Broca's area
84
Where is Broca's area located + what does it do?
Left frontal lobe, controls fluent speech
85
What does the temporal lobe do?
Contains auditory cortices, associated with long term memory + emotion + contains Wernicke's area
86
What does the temporal lobe do?
Contains auditory cortices, associated with long term memory + emotion + contains Wernicke's area
87
Where is Wernicke's area located + what does it do?
Located close to auditory cortex, in the posterior 2/3 of the temporal lobe, associated with understanding speech + written language
88
How many peduncles does the cerebellum have?
3
89
What does the cerebellum do?
Helps maintain posture + balance, receives info from vestibulocochlear organs
90
What does the brainstem consist of?
Pons, medulla, midbrain
91
What can the midbrain be divided into?
Tectum + tegmentum
92
What are the red nuclei?
Structure in the tegmentum associated with motor function
93
Why is the red nuclei red?
Contains iron in 2 forms: haemoglobin + ferritin
94
What is the substantia nigra + what condition is associated with its degeneration?
Tegmentum structure important for the production of dopamine. Its degeneration is associated with Parkinson's
95
What functions are controlled by the pons?
Breathing, sleeping, swallowing, bladder control
96
What functions are controlled by the medulla?
Autonomic regulation-heart rate, breathing + blood pressure
97
What are UMN?
Upper motor neurons-travel from motor cortex through internal capsule + pyramidal tracts to spinal cord
98
What are LMN?
Lower motor neurons-neurons that exit the spinal cord to innervate muscles
99
What are signs of UMN damage?
If injury/lesion is above medulla, then damage will be mainly contralateral, if below then ipsi
Spasticity + stiffness-can develop over time
Abnormal increased reflexes e.g. Babinski's
100
What are signs of LMN damage?
Muscle weakness + atrophy
Loss of reflexes
101
The motor/descending/efferent pathways can be divided into what 2 classes of tracts?
Pyramidal + extrapyramidal
102
Name the 2 pyramidal tracts + the difference between them. Do they decussate?
Corticospinal-anterior + lateral (descends to spinal cord + supplies rest of body) + corticobulbar (terminates in brainstem as supplies head + neck). Lateral corticospinal decussates in pyramid of medulla, anterior corticospinal stays ipsilateral
103
Name the 4 extrapyramidal tracts + whether they decussate or not
Reticulospinal-no
Vestibulospinal-no
Rubrospinal-yes
Tectospinal-yes
104
What do the corticospinal tracts control?
Conduct motor impulses
105
What are the reticulospinal tracts associated with?
Voluntary muscle + muscle tone
106
What are the vestibulospinal tracts associated with?
Anti-gravity muscles
107
What are the rubrospinal tracts associated with?
Upper limb flexion
108
What are the tectospinal tracts associated with?
Reflexive localisation of auditory + visual stimuli
109
Name the 3 ascending tracts + whether they decussate
DCML-yes, spinothalamic-yes, spinocerebellar-no
110
Describe the action of the knee jerk/patellar reflex
1. Patella tendon is tapped, causing it to stretch
2. Muscle spindle in quadriceps detects stretching + carries sensory info to spinal cord
3. Motor neurons cause immediate contraction of quadriceps muscle
4. Sensory neurons also stimulate interneurons that inhibit activity of motor neurons that supply opposing muscle-hamstring
means action of quadriceps is unopposed
Extensor muscle contracts + flexor muscle relaxes=knee jerk
111
What do sensory receptors do?
Respond to stimuli
112
What are sub-modalities?
Variations within a stimulus e.g. pitch + volume within auditory stimuli
113
What can the autonomic nervous system be divided into?
Sympathetic + parasympathetic
114
Name the neurotransmitter released at the effector by the somatic nervous system
Acetylcholine
115
Name the neurotransmitter released at the effector by the somatic nervous system
Acetylcholine + Noradrenaline
116
What are the differences between somatic + autonomic neurons?
Somatic-single neuron from CNS to effector
-heavily myelinated axons
Autonomic-2 neurons from CNS to effector
-lightly myelinated pre-ganglionic axon + unmyelinated postganglionic axon
117
What is the normal resting potential?
-70mV
118
What is the threshold for an action potential to be fired?
Cell has to depolarise to -55mV
119
At what potential do sodium channels close + potassium channels open during an action potential?
30mV
120
What is an absolute refractory period?
After an action potential, when it is impossible for another action potential to fire
121
What is a relative refractory period?
After the absolute refractory period, when an action potential can be triggered if the stimulus is large enough
122
What is Brown-Sequard syndrome?
An incomplete spinal cord lesion, characterised by weakness on one side + loss of sensation on the opposite side
123
What are tonic receptors?
Slow adapting receptors
124
What are phasic receptors?
Rapid adapting receptors
125
What are Merkel's discs?
Tonic receptors that respond to pressure
126
What are Meissner's corpuscles?
Phasic receptors, in the dermis of the skin, enable fine touch
127
What are Pacinian corpuscles?
Phasic receptors that respond to pressure changes + vibration
128
Which kidney is normally lower + why?
Right, pushed down by liver
129
What spinal level do the kidneys sit at?
T12-L3
130
What are the ureteric walls made up of, why is this necessary?
Smooth muscle-to allow peristaltic waves
131
What 3 sites does the ureter narrow at?
Pelvic brim
Where pelvis of kidney becomes ureter
Where ureter passes through the bladder
132
What stops urine passing back up the ureter from the bladder?
Urine enters at an oblique angle, as bladder fills, it presses on part of the ureter in the bladder wall, stopping urine from backing up
133
How long is the female urethra?
2 inches
134
How long is the male urethra?
8-10 inches
135
What are the types of nephron + what is the difference between them?
Cortical-tubules extend only a short distance into medulla + juxtamedullary-tubules extend deep into the medulla
136
What is the renal corpuscle?
Part of the nephron where blood plasma is filtered
137
What kind of epithelium lines the proximal convoluted tubules?
Cuboidal
138
What kind of epithelium lines the loop of Henle?
Squamous
139
What is the purpose of podocytes in the filtration barrier?
Podocytes are negatively charged so prevent passage of albumin
140
Name 4 factors that determine glomerular filtration
Size of molecule
Pressure
Charge of molecule
Rate of blood flow
141
What % of cardiac output does renal blood flow make up?
20%
142
What is GFR (kidneys)?
Glomerular filtration rate
143
Name 3 ways in which GFR is regulated
Renin-angiotensin system
Tubuloglomerular feedback
Autonomic vasoreactive reflex
