Qs Flashcards
Periodic acid schiff stains
stains hexose sugar (ie basement membranes) magenta
Alcian blue stains
Alcian blue stains Glycoaminoglycan rich structures blue e.g goblet cells
Haemotoxylin stains
haemotoxylin is a stain that is used to stain cell nuclei and RNA blue
Eosin stains
Eosin stains cytoplasm and colloidal proteins pink/ Keratin orangey-red
Ziehl Nielsen stains
Stain used to identify acid fast bacilli
Why is gastrin crucial for the digestion of proteins?
Conversion of pepsinogen to pepsin (enzyme that breaks down proteins) requires a low pH. Gastrin is a chemical that increases gastric acid release in the stomach.
The absorption of which monosaccharide(s) require energy from ATP?
Glucose and galactose (secondary active transport)
The absorption of which monosaccharide(s) DO NOT require energy from ATP
Fructose (facilitated diffusion)
Which vitamin is important for producing blood clotting factors? What clotting factors does it produce?
Vitamin K (Mnemonic 1972) clotting factor 2, 7, 9, 10
Unconjugated bilirubin is converted to conjugated bilirubin through what enzyme?
Glucuronyl transferase
What stage of the urea cycle is the enzyme carbomoyl phosphate synthetase important for
Conversion of ornithine to citrulline
List 4 functions of albumin
- Anticoagulation
- Maintenance of oncotic pressure
- Neutralisation of free radicals
- Bind to and transport bilirubin
Transamination process
Transamination involves transfer of an α-amino group from one an amino acid to a keto acid
Aminoacid + α-ketoglutarate ↔ α-keto acid + glutamate
Cytochrome p450 enzyme makes xenobiotics more water soluble for excretion. How?
To allow molecules to be excreted, cytochrome P450 enzymes oxidise molecules making them more water soluble
Phase 1:
Makes polar, water soluble molecules through hydrolysis, oxidation (by cytochrome P450 enzymes) or reduction
Phase 2:
Yields large, water soluble, inactivated molecules by adding hydrophilic groups such as glucuronic acid
What is the Acheson’s Report 1998?
Reducing income inequality was an important step in reducing health inequalities.
Emphasis should be put on the health of families with children to reduce health inequalities in future.
It recommended that all policies that may impact health should undergo health assessments to see what impact they will have
What is the Black Report (1980)?
Black report found that there are inequalities in mortality between different social groups, also working class people have less access to and less uptake of preventative measures
Define sensitivity
The likelihood of a positive person by test being positive
Define specificity
The likelihood of a negative person by test being negative
Define positive predictive value
The probability of the test picking up someone positive
Negative predicted value
The probability of the test proving someone negative
Multibed nucleus - pale red and blue cytoplasmic granules describe which leukocyte
Neutrophils
Bilobed nucleus, red cytoplasmic granules describe which leukocyte
Eosinophils
Bilobed nucleus, purplish-black cytoplasmic granules describe which leukocyte
Basophils
Large spherical nucleus, thin rim of pale blue cytoplasm describes which leukocyte
Lymphocytes
Kidney-shaped nucleus, abundant pale blue cytoplasm describes which leukocyte
Monocyte
What is thrombin’s role in blood coagulation?
Thrombin is an enzyme which converts fibrinogen into insoluble fibrin which is an essential component of a blood clot
What is thromboxane A2’s role in blood coagulation?
Thromboxane A2 amplifies platelet activation and recruits additional platelets
What is Factor Xa’s role in blood coagulation?
Factor Xa catalyses the production of prothrombin to thrombin
What is Von Willerbrand (VWF) factor’s role in blood coagulation?
It allows platelets to bind to exposed collagen fibres
Daniel a 65 year old male presents in A&E with expressive aphasia (difficulty finding and saying the right words) and difficulty understanding speech. He also had weakness and drooping in his right arm but his massive quads (leg muscles) were still functioning normally.
Which artery is likely occluded causing such symptoms?
Left middle cerebral artery
What lobe does Baums loop pass through?
Parietal lobe
What lobe does Meyers loop pass through?
Temporal lobe
The cerebellum coordinates movement and balance attached to the brainstem by 3 peduncles. Injuries to the cerebellar can cause loss of coordination, intention tremors, hypotonia and nystagmus (abnormal eye movements)and more.
What percentage of the brains neurons make up the cerebellum?
80%
What detects muscle tension? What are they innervated by?
Golgi tendon organs, afferent 1b fibres
What do muscle spindles detect? What are they innervated by?
Muscle spindles are stretch receptors that consist of intrafusal muscle fibers enclosed in a sheath (spindle) innervated by type 1a and 2 afferent sensory nerves.
What do extrafusal muscle fibres detect? What are they innervated by?
Extrafusal muscle fibers are the standard skeletal muscle fibers that are innervated by alpha motor neurons and generate tension by contracting, thereby allowing for skeletal movement.
Sagar, a 50 year old male known for ego-lifting, is in the gym. He decides to train his biceps by curling a very heavy weight, however he realises his arms are physically unable to lift the weight which confuses him. Most of the time this could be due to fatigue and too weak a muscle however in this case its because of a protective reflex preventing muscle injury by inhibiting full contractile engagement of the biceps muscle. What reflex is doing this?
Golgi tendon reflex
What are the branches of Cn VII?
The Zebra Bit My Cat - Temporal, Zygomatic, Buccal, Marginal Mandibular, Cervical
What do the semi-circular canals control?
Rotational/Head movements
What 2 structures make up the otolith organs?
The saccule and utricle
What does the saccule control?
Vertical movements
What does the utricle control?
Horizontal movements
What are the five layers of the epidermis
- Stratum corneum
- Stratum lucideum
- Stratum granulosom
- Stratum spinosum
- Stratum basale
Where are the Pacinian and Meissner corpuscles located?
Pacinian is located in dermis
Meissner is located just beneath the epidermis in the dermal papillae
IgA functions?
Is present in mucous secretions, second most common and protects from bacteria
IgD function?
Found in blood and lymphatics and is present on immature B cells
IgE function?
Lowest amount in blood effective against parasitic infections
IgG function?
Most common antibody, can cross the placental barrier to provide passive immunity and remember pathogen
IgM function?
First antibody that interacts with a new bacteria, initiates the primary immune response
Oesophagus epithelium
Non keratinised stratified squamous epithelium
Large intestine walls epithelium
Simple columnar
Skin epithelium
Keratinised stratified squamous
Renal pelvis epithelium
Urothelium
Respiratory tract epithelium
Ciliated pseudostratified columnar with interspersed goblet cells
What are the products of ketogenesis?
Acetone and B-hydroxybutyrate
What happens to the products of ketogenesis
Acetone is expired by lungs, B-hydroxybutyrate is used as fuel in muscles and tissues
Where is the site of ketogenesis? Can it use ketone bodies as fuel?
The liver. No, as it lacks the appropriate enzymes
Main site of spermatogenesis
In the seminiferous tubules
Which adrenoreceptor is most sensitive to adrenaline compared to noradrenaline?
β2 receptor
Which adrenoreceptor is the dominant receptor for adrenaline and noradrenaline
β1 receptor
Which artery does the right gastric artery arise from?
The proper hepatic artery
Which artery does the left gastric artery arise from?
The coeliac trunk
What two structures does the ductus venosus connect in the fetus?
IVC and the umbilical vein
What type of epithelium is the ectocervix covered by?
Stratified squamous non-keratinised epithelium
What nerve supplies the pericardium?
The phrenic nerve
Which blood vessels supplies approximately 1/3rd of the blood supply to the liver?
Hepatic artery proper
What forms the borders of the femoral triangle
Lateral - sartorius
Superior - inguinal canal
Medially - adductor longus
A 52 year old man has a suspected brain tumour. He is experiencing vision loss in his temporal visual fields. Where is the most likely site of damage?
The optic chiasm
What passes through the cavernous sinus
O TOM CAT
top to bottom: oculomotor (III), trochlear (IV), ophthalmic branch of trigeminal (V - 1), maxillary branch of trigeminal (V - 2),
lateral to medial: carotid artery (internal), abducens (VI), trochlear (IV)
Foregut blood and nerve supply?
coeliac trunk, greater splanchnic nerve, T5-T9
Midgut blood and nerve supply?
SMA, less splanchnic nerve, T10-T11
Hindgut blood and nerve supply?
IMA, least splanchnic nerve, T12
Which part of the bowel contains the epiploic appendages?
The large bowel
What type of epithelium lines the gallbladder?
Simple columnar with poorly developed brush border
What is the name given to the structure that unites the right and left lobes of the thyroid?
The isthmus
What causes an increase in insertion of aquaporin 2 in collecting duct, increasing water retention?
Vasopressin
What is alveolar dead space?
Volume of air that reaches alveoli but never participates in respiration
Which clotting factor is not produced by the liver?
VIII
What vertebral level is the Carina found at?
T4
What does McBurney’s point indicate the location of?
Appendix - right-hand side, 1/3 of the distance from the ASIS to the umbilicus.
What is the function of topoisomerase enzymes?
Relieving supercoiling
Where is angiotensin produced?
Liver
What are chondrocytes?
Cells that secrete extracellular matrix components of cartilage
What term is used to describe ‘the increase in the size of a tissue due to an increase in the number of cells’
Hyperplasia
How many essential amino acids are there?
9
What transport is Na+/K+ -ATPase?
Primary active transport
Which of the following cell types has a reniform nucleus (kidney bean)?
Monocyte
Which artery is the main supply to the atrioventricular node (AVN)?
Posterior interventricular artery
There are many types of research study but some are considered more reliable than others. What type of research study is considered to be the “golden standard”?
Randomised control trial
Fluid is absorbed in the gastrointestinal tract by the small intestine. What percentage of fluid is absorbed in the small intestine?
80%
SIADH has a genetic component to it. What is a method of genetic testing in pregnancy?
Chorionic villus sampling OR amniocentesis
Haematopoiesis occurs in a different place in the foetus compared to an adult. Where does haematopoiesis occur in an adult and where does it occur in a foetus?
Adult = axial bone marrow
Foetus = one of: yolk sac OR liver OR spleen
State the structural differences of foetal haemoglobin compared to adult haemoglobin.
Foetal = 2 alpha & 2 gamma chains
Adult = 2 alpha & 2 beta
A woman who gave birth at the Royal Hallamshire Hospital suffers severe blood loss as a result of postpartum haemorrhage. Why does the haematocrit not change following a major trauma in which a lot of blood is lost?
Haematocrit is the ratio of red blood cells to blood volume, this does not change because the ratio is unaffected by blood loss because you’re losing the same ratio of RBCs to blood volume
Name a method that can be used to measure total lung capacity.
Gas dilution OR total body plethysmography (body box)
Where in the stomach are you most likely to find Enteroendocrine (G) cells?
In the antrum
What vitamins are absorbed in the ileum
Vitamin A D E K (all the fat soluble ones!!)
Differences between retrospective and prospective cohort studies?
In prospective studies, individuals are followed over time and data about them is collected as their characteristics or circumstances change. Birth cohort studies are a good example of prospective studies. In retrospective studies, individuals are sampled and information is collected about their past.
What best describes the relationships of BP & SVR with the parasympathetic nervous system?
Parasympathetic nerves do not have a major influence on peripheral blood vessel diameter as blood vessels do not have parasympathetic innervation.
What best describes the relationships of SVR & BP with the sympathetic nervous system?
Sympathetic nervous system causes blood vessels to constrict (vasoconstriction) this leads to an increase in SVR.
When does the oropharyngeal membrane rupture?
4th week
Paraesthesia in the pinky finger and medial half of the ring finger is due to damage to which nerve?
Ulnar
In which stage of the cell cycle are the chromosomes duplicated?
S stage
‘Wrist drop’ is a characteristic sign seen when patients cannot extend the wrist. What nerve is commonly affected to provide this presentation?
The radial nerve
Which nerve roots are involved in the brachioradialis jerk reflex?
C5 C6
S1-2 :ankle jerk
L3-4 :knee jerk
C5-6 :brachioradialis jerk
C7-8 :triceps jerk
A 65-year-old man presents to A&E with sudden shortness of breath after accidentally inhaling food during mealtime. Which bronchus is this food most likely to have become lodged in and why? (3 marks)
Right main bronchus
The R bronchus is more vertically disposed (1)
And wider than L bronchus (1)
So more likely foreign body trapped in right main bronchus
Describe the anatomical structure of lower respiratory tract from the trachea to the alveoli. (3 marks)
Trachea -> main bronchi -> lobar bronchi -> (1)
segmental branches -> respiratory bronchiole -> (1)
terminal bronchiole -> alveolar ducts and alveoli (1)
Give the 3 inferior borders of both lungs (6 marks)
6th rib in mid clavicular line (2)
8th rib in midaxillary line (2)
10th rib posteriorly (2)
Give the name of the organ, innervation and nerve roots of the organ that meets the inferior border of the lungs (3 marks)
Organ: diaphragm (1)
Innervation: phrenic nerves (1)
Nerve roots: C3,4,5 (keeps the diaphragm alive!) (1)
How many ATP molecules are produced per turn of the citric acid cycle?
12 ATP
Mitosis and meiosis are both ways in which cells divide. Meiotic division produces genetically different daughter cells. What causes genetic variation in meiosis and during what phases
Crossing over occurs in prophase 1
Random/independent assortment occurs in metaphase 1
At what range of BMI is a patient overweight
25-29.9
Name 3 types of glial cells and briefly describe their functions
Oligodendrocytes - myelinates the cells of the CNS
Astrocytes - forms the blood brain barrier, aids in development of synapses as well as providing structural support for synapses
Microglia - immune cells of the CNS
Briefly explain the process of neurotransmitter release across the synapse, starting from the action potential arriving at the presynaptic neuron. (3)
- Calcium ion channels open when an action potential reaches the pre-synaptic terminal (1)
- Ca2+ ions cause vesicles containing neurotransmitter to fuse with the membrane and release their contents (1)
- Neurotransmitter diffuses across the synaptic cleft and attaches to receptor sites on the post-synaptic membrane (1)
Name 2 fast neurotransmitters (1)
Acetylcholine (0.5), Glutamate (0.5), GABA (0.5)
Name 2 neuromodulators (slower acting) (1)
Dopamine (0.5), Serotonin (0.5), Noradrenaline (0.5)
List the role of pepsin in protein digestion (3 marks)
Breaks down collagen in meat helping to increase the surface area for digestion, accelerated protein digestion, essential for vit B-12 in the small intestine
List two causes of delayed gastric emptying (2 marks)
Idiopathic, abdominal surgeries, autonomic neuropathies, parkinsons
List the 3 components of the portal triad
Common bile duct, portal vein, common hepatic artery
What anatomical structure runs on the external surface of the liver between the left and right lobes?
Falciform ligament
The liver is important for the detoxification of compounds in the blood, give 2 examples of phase 2 metabolism reactions
Glucuronidation, conjugation
He has raised serum T3 and T4. Name the hormone in full that is secreted by the anterior pituitary that may have caused this.
Thyroid stimulating hormone
What hormone, released by the hypothalamus, is usually responsible for regulation of secretion of TSH? Again name in full.
Thyrotropin releasing hormone
What cells are responsible for ‘pacemaking’ during peristalsis in the bowel
interstitial cells of cajal
Where is Vitamin A stored
Ito cells of the Space of Disse
What hormone stimulates RBC production and where is it released from (2)
erythropoietin from the kidneys
What connects adjacent alveoli that allows movement of macrophages
Pores of Kohn
A patient presents to you with a chronic cough and shortness of breath. He says he has been a smoker for the last 40 years and smoked at least a pack a day. You suspect he has COPD. If your diagnosis is correct, what would you expect to see using his FEV1/FVC
FEV1/FVC <70%
A patient presents to you after inhaling a peanut, where is the peanut most likely lodged and why (2)
right bronchus - it is wider and more vertically disposed
What enzyme converts angiotensin 1 to angiotensin 2 and where is it produced
Angiotensin converting enzyme - produced in the lungs
A young sports man has presented to you with what an acutely painful left knee. On examination they have a positive lachman’s test, what has most likely caused the acute pain
damage to the ACL (lachman’s test is diagnostic for ACL injury)
When staining samples, you may use a specific stain for molecules that are present specifically in that tissue. Blood is high in iron, what stain may be used to detect iron (1)
Perls’s prussian blue
The body has many different types of joints, what are 4 different types of joints found in the body (4)
hinge, pivot, plane, ball and socket, condyloid, saddle
There are different types of bones found in the body, give an example of a sesamoid/irregular bone (1)
Patella
where is albumin produced (1)
liver
if a patient has lost a lot of water, what will detect this and where are these found (2)
osmoreceptors - found in the hypothalamus
Name 3 structures forming the vascular layer of the eye
Choroid, Ciliary body, Iris
What’s the name of the part of the thalamus, in which the optic tract synapses?
Lateral geniculate body
Later that day the ophthalmologist sees Mr Green. He presents with a
weakness of downward eye movement and double vision. He complains that it makes it difficult for him to walk down the stairs and that tilting his head helps. Damage to which cranial nerve would cause these symptoms?
Trochlear Nerve
The primary visual cortex is located in the occipital lobe. Which sulcus of the
occipital lobe is the primary visual cortex located near?
Calcarine sulcus
Susie is a Phase 1 medical student preparing in the university library for her mock exam. When she’s about to go for a short lunch break, she smells a foul scent. Judging by the confused faces of the students surrounding her, she’s not alone in that rather upsetting situation. In fact, the odour has spread all around the library. In which part of the brain is the olfactory cortex located?
Uncus
In which structure do olfactory receptor cells synapse?
Olfactory bulb
Which foramen separates the middle ear and Scala vestibuli
Scala vestibuli = oval window
Which foramen separates the middle ear and Scala tympani
Scala tympani = round window
The spermatic cord is a structure that passes through the inguinal canal. Name all the structures in the spermatic cord (3 arteries, 2 nerves, 3 “other” structures)
Arteries: testicular artery, cremasteric artery, artery of the ducts deferens,
Nerves: genital branch of genitofemoral nerve - nerve to the cremasteric muscle, testicular nerves,
Structures: tunica vaginalis, pampiniform plexus, vas deferens
The left gonadal vein has a different anatomical course to the right gonadal vein. Which vessel does the left and right gonadal (ovarian/ testicular) vein drain into?
Left gonadal vein: Left renal vein
Right gonadal vein: IVC
Which nerve, providing sensation to the inner thigh, runs behind the ovary?
Obturator nerve
What kind of epithelium is found in the: - Proximal part of penile urethra
Proximal part of penile urethra = pseudostratified columnar epithelium
Distal part of penile urethra epithelium
non-keratinising stratified squamous epithelium
The UTI is found to have spread up the urinary tract into the bladder. The start of the urethra lies within the bladder. In which region of the bladder does the start of the urethra lie?
The trigone of the bladder
The F1, is concerned about a lack of sensation in certain parts of the hand.
She suspects that this is caused by a nerve being damaged during the fall. Which nerve is the most likely to supply the skin on the palmar aspect of the index finger?
Median nerve
A man consumes 1 unit of alcohol. How many grams of carbohydrate would he have to consume to receive the same amount of kcal?
Alcohol has 7kcal/g and each unit of alcohol is 8g (not 10g, it’s 10ml)
This means 1 unit of alcohol is 56kcal (7kcal/g x 8g)
To get 56kcal of carbohydrates which is 4kcal/g, you would need 56kcal / 4kcal/g = 14g
Mr. Green is a 68 year old man who presents to A/E with a history of central crushing chest pain with pain radiating down his left arm.
An ECG is performed which shows ST elevation in leads II, III and aVF. The doctor who reviews the ECG suspects an ST-elevation myocardial infarction (STEMI). Based off the ECG findings, which artery is most likely to have been affected?
Right Coronary Artery
Name the 2 respiratory centres that are found in the pontine respiratory group?
Apneustic centre (2M), pneumotaxic centre (2M)
Alveolar pneumocytes are either type 1 or type 2. State the equation involving alveolar air flow and radius. (2 marks)
Equation; P= 2T/r , aka as Laplace’s Law (1)
Gell and Coombs’ classification is used to define hypersensitivity reactions. Define (in simple terms) what a type 2, type 3 and type 4 hypersensitivity reaction is.
Type 2 : Antigen - Antibody complex formation (1)
Type 3 : Immune complex deposition (1)
Type 4 : Delayed T cell mediated hypersensitivity (1)
What is the anatomical location of the sinoatrial node called on the heart? (1 mark)
Sulcus terminalis
Damage to which structures are responsible for Uncoordinated movement (a region of the CNS)
Cerebellum
In the rostral lower regions of the brain, you may find a blue pigmented area which has many serotonergic neurons. What is this location known as? (1 mark)
Nucleus accumbens
Fill in the blanks of this catecholamine synthesis pathway (2 marks)
TYROSINE → ……………… → DOPAMINE → ………………………….. → ADRENALINE
DOPA (1), Noradrenaline
The basal ganglia modulates movement by acting directly on descending motor tracts. Name the 2 descending pyramidal tracts. (2 marks)
The corticospinal and the corticobulbar tracts
On a visual field test, you note a left homonymous hemianopia. Where is the visual pathway lesioned? (2 marks)
Caudal to the optic chiasm/ in the optic radiations after the optic chiasm (1) on the right hand side (1)
Upon examination, you also notice what you deem to be a cranial nerve XI lesion (spinal accessory nerve). Name 2 ways you could test weakness of the muscles supplied. (2 marks)
Shrugging shoulders vs resistance - trapezii (1) and turning head vs resistance - sternocleidomastoid (1)
- An elderly male, Mr Hussain, presents with a swelling in his testicle which looks like a bag of worms. You diagnose him with a varicocele. This varicocele is found to be as a result
of a kidney tumour occluding the testicular venous drainage.
a. What side is a varicocele most likely to be located on and why? (2 marks)
Left (1) because the left testicular vein drains into the left renal vein before entering into the IVC (so any renal obstructions e.g. tumour can lodge in the left testicular vein directly) (1)
Where in the nephron does Vasopressin act? (1 mark)
collecting duct
Describe the 3 steps of primary platelet plug formation (3 marks)
Adhesion (1) of platelets to vWF on the collagen, Aggregation (1) of platelets together, Activation (1) from discoid to pseudopoid
What do parafollicular thyroid cells secrete? (1 mark)
Calcitonin
She tells you she used to play cricket but has damaged her rotator cuff muscles so no longer can. Name the muscles of the rotator cuff. (4 marks)
SITS
Supraspinatus
Infraspinatus
Teres minor
Subscapularis
- A very annoyed Ibraheem presents with leg issues which he first noticed when he returned from his holiday to Paris. Abroad, he hardly noticed the issue as he would drive
automatic cars, but since returning to his manual car in London, his clutch control has been poor. His foot also drags when he’s walking up the stairs.
a. Name the nerve affected and its nerve root. (2 marks)
Common peroneal nerve palsy (1) with L5 nerve root (1)
Osteoblasts signal osteoclasts to break down bone using what? (1 mark)
RANK ligands
Name the mineral component of bone (made of calcium and phosphorus) and state
the type of collagen present in cartilage. (2 marks)
Hydroxyapatite
Type II collagen
Name the type of saliva produced by the parotid gland and its innervation
Serous acini
facial nerve passes by, but it’s the glossopharyngeal nerve which innervates it
At what level does the duodenal papilla enter the duodenum?
L1 - L3 the second portion of the duodenum
Kupffer cells function
Protects the liver from infections
Involved in the breakdown of RBCs, also stores iron in the form of ferrin
Where is bile produced and stored
Bile is produced by hepatocytes and is stored in the gallbladder
What is at the centre of the classic liver lobule?
The central hepatic venule
Which cells produce elastin?
Fibroblasts
What are the sites of synthesis of: ADH, aldosterone and renin?
ADH is produced in the hypothalamus, aldosterone is produced in the adrenal cortex,
renin is produced by the juxtaglomerular cells in the kidney
Which 2 proteins are involved in the generation of ciliary movement?
Tubulin and dyelin
What is a gene sequence coded in?
Single strand DNA
What is a promoter sequence coded in?
A promoter sequence is coded in single strand DNA
What is the transcriptome composed of?
All the RNA present in a cell
What happens to abnormal HbS in hypoxia or deoxygenated states?
They polymerise and crystalise
What are the 3 types of cytoskeleton and what size are they each?
Types of cytoskeleton filaments: actin 5nm, intermediate filaments eg desmin/nuclear laminin/vimentin/keratin 10nm, microtubule 25nm
Define gonadal mosaicism and non-disjunction
Nondisjunction: occurs when homologous chromosomes fail to separate in M1 OR sister chromatids fail to separate in M2. Gonadal Mosaicism: occurs when precursor
germline cells to ova or spermatozoa involve a mixture of 2 or more genetically different cell lines- this may occur due to random mutation in the germline cells that undergo mitosis leading to mutated gametes, or due to errors in mitosis during
gametogenesis; the result is such that one cell line is normal and the other is
mutated.
When is beta oxidation used?
Beta oxidation is used in aerobic conditions as fuel when there is increased demand e.g. during fasting or states of low blood glucose. However it cannot be used as fuel
for the nervous system because fatty acids cannot pass the blood-brain barrier
John is a 65-year-old man with a 20-pack year history. He comes into the GP complaining of breathlessness on exertion and that he is no longer able to walk without resting every 1 minute. He is worried about his condition and wants to know more.
What would his predicted FEV1 and FEV1/FVC be?
John likely has COPD which has an obstructive lung pattern. Hence, his FEV1 would be reduced below 80% while his FVC would also be reduced but may not decrease as much as
FVC. Therefore, FEV1/FVC would likely by higher or normal
What stimulates the central chemoreceptors to increase respiratory rate?
H+, Central chemoreceptors detect changes in H+ while peripheral chemoreceptors detect changes in H+ and also PaO2
Which week of gestation is Type 2 pneumocyte produced?
week 34
What makes up the conducting and respiratory zone?
Conducting zone
1. Bronchi
2. Bronchioles
3. Terminal bronchioles
Respiratory zone
1. Respiratory bronchioles
2. Alveolar ducts
3. Alveolar sacs
Derrick is a retired old man who has recently discovered a tumor around his neck. He complains that he feels pain whenever he drinks alcohol and has also lost weight over the
last few months. Only recently, he realised that his voice has become hoarse. Why has his voice turned hoarse?
Damage to recurrent laryngeal nerve
Molly was strolling in the park one lovely morning when she got stung by a bee. She developed an allergic reaction and was rushed into the hospital. She is currently hypotensive
and has difficulty breathing. What should she be given?
Adrenaline
Briefly describe the mechanism of bronchodilation.
Adrenaline binds to beta-2 receptors that are coupled with Gs protein. This leads to adenylyl cyclase activation and increased cAMP. Increased cAMP levels cause a decrease in intracellular calcium which therefore leads to bronchodilation.
Briefly describe the mechanism of bronchoconstriction.
ACh binds to the muscarinic-3 receptors coupled to Gq protein. Phospholipase C is activated and catalyses the breakdown of membrane phospholipids into diacylglycerol (DAG) and inositol triphosphate (IP3). IP3 binds to ligand-gated calcium channels causing calcium release and bronchoconstriction.
What is the consequence of an LAD occlusion, and a RCA occlusion?.
LAD occlusion will impair conducting ability; RCA occlusion will cause an inferior myocardial infarction
What causes the dicrotic notch?
The dicrotic notch is caused by an increase in aortic pressure upon closure of the aortic valve- this happens due to the blood rebounding against the valve
In 20% of people, the posterior interventricular artery is supplied by both the circumflex and the RCA. What is the joint artery between the circumflex and RCA called?
Anastomosis
Explain the role of the Medullary Cardiovascular Centre in central circulation control
The medullary cardiovascular centre contains the sympathetic pressor region (causes increased BP by increasing vasocontriction), and the parasympathetic depressor region (causes decreased BP by inhibiting the pressor region)
Which nerve provides parasympathetic innervation of the heart?
The vagus nerve
Define tachycardia and bradycardia
Tachycardia: fast heart rate over 100bpm; bradychardia: slow heart rate below 60bpm
What is pulmonary oedema in the presence of normal central venous pressure a sign of?
Pulmonary oedema in the presence of normal central venous pressure is a sign of left heart failure. If the left side of the heart is impaired, blood backs up to the pulmonary system, leading to increased hydrostatic pressure and blood leaving the vessels into the tissues (oedema); raised central venous pressure indicates right side
failure
What is severe pulmonary hypertension a cause of?
Right sided heart failure. Severe pulmonary hypertension is a cause of right side heart failure. Severe
pulmonary hypertension means the right ventricle must work harder to pump blood through the pulmonary artery, so the right ventricle is unable to generate sufficient pressure and starts to fail
Describe the process by which the first breath taken by a foetus causes a transition from foetal circulation to post-natal circulation
Fluid is removed from the lungs.
Adrenaline increases surfactant release.
Air is inhaled.
O2 VASODILATES pulmonary vessels.
Umbilical arteries and ductus arteriosus constricts. Foramen ovale closes.
What do the first and second heart fields produce?
The first heart field develops into the left ventricle; the second heart field develops into the right ventricle, atria and outflow tracts
Where are the pacemaker cells located?
The SAN
The proximal convoluted tubule is responsible for bulk reabsorption of Na+, Cl- and other solutes. Reduced blood flow to this area causes significant damage. Explain why. (2 marks)
The absorption of these electrolytes etc is very energy intensive, and the proximal convoluted tubule has many active transport pumps, and the cytoplasm of the endothelial cells here is rich in mitochondria. Lack of blood supply means that less ATP can be produced so these transport pumps cannot function, so the renal tubules
are damaged.
2 key cell types found in the collecting ducts are Principal cells and Intercalated cells. Describe, briefly, the role of each. (2 marks)
Principal cells are the main Na+ reabsorbing cells and are the site of action of aldosterone. Intercalated cells are involved in acid-base balance by mediating H+ and HCO3 secretion and K+ and Cl- reabsorption. (Mark per sentence)
From which germ layer does the urogenital system arise?
The intermediate mesoderm
In which layer of the skin are Melanocytes found?
Basal layer
What is the action of ADH
When the RAAS system is stimulated, ADH is released from the posterior pituitary gland. Where, in the kidney, ADH binds to V2R receptors (G-protein coupled receptors), increasing the transcription of Aquaporin-2 channels and increasing the insertion of these channels into the apical membrane of the principal cells. The permeability of the cells is increased, allowing water to flow down its concentration gradient into the cell and then over the basolateral membrane into the bloodstream through aquaporin-3 and -4 channels. The total blood volume therefore increases, plasma osmolarity is normalised and urine becomes more concentrated.
- A 60-year-old woman with hypocalcaemia has raised parathyroid hormone levels. This is a normal
physiological response to try and raise her calcium levels.
a) What are the actions of parathyroid hormones? (4)
Indirect stimulation of osteoclast/direct stimulation of osteoblast to resorb
bone and release calcium into blood.
● Increases intestinal calcium absorption by increasing activated vitamin D.
Activated vitamin D increases calcium absorption.
● Active reabsorption of calcium and magnesium from the distal convoluted
tubule.
Decreases reabsorption of phosphate.
Where are incretins secreted from and what are their functions? (2)
b) Give 2 examples of incretins (2)
a) Incretins are secreted by endothelial cells in the GI tract. Its function is to increase the effect of insulin response to glucose
b) Glucagon like peptide. (GLP-1)
Glucagon dependent insulinotropic peptide. (GIP)
How is the pituitary gland connected to the hypothalamus
Through the infundibulum
Where is the thyroid gland located? (vertebrae level)
C5 - T1
b) What divides the thyroid gland into 2 lobes? (1)
The isthmus
Where do the the uterine and vaginal arteries arise from ?
Both the uterine and vaginal arteries arise from the internal pudendal arteries.
b) What is the pathway of sperm to the outside? (2)
SREEVE UP
seminiferous tubules -> rete testis -> efferent duct -> epididymis -> vas deferen -> ejaculatory duct -> urethra -> penile urethra
Describe the embryology of the brain:
Prosencephalon:
- telencephalon -> lateral ventricles + cerebral hemisphere
- diencephalon -> thalamus + hypothalamus + 3rd ventricle
Mesencephalon:
-> midbrain + cerebral aqueduct
Rhombencephalon:
- Metencephalon -> cerebellum + pons + upper 4th ventricle
- Myelencephalon -> Medulla + lower 4th ventricle
Explain how alcohol is metabolised by the liver. (3 marks)
Alcohol is converted to acetaldehyde by alcohol dehydrogenase (1)
- Acetaldehyde dehydrogenase then converts acetaldehyde into acetate (1)
- This is then broken down into carbon dioxide and water (1)
Explain how the biliverdin is metabolised and excreted. (6
marks)
Unconjugated bilirubin is insoluble and so binds to albumin (1) in the blood to
be transported to the liver
- In the liver, unconjugated bilirubin undergoes glucuronidation/glucuronic acid is added to convert it into conjugated bilirubin (1)
- This is achieved with the help of UDP glucuronyl transferase (1)
- Conjugated bilirubin is soluble so can be dissolved in the bile, which travels to
the gallbladder to be stored and to the small intestine to be reduced into
urobilinogen (1)
- Urobilinogen is lipid soluble; this can be reabsorbed into the blood and
returned to the liver to be oxidised into urobilin (1) where it is recycled into bile
or excreted in urine
- Urobilinogen can also be oxidised into stercobilin by intestinal bacteria (1),
which is then excreted in faeces
Describe how antibodies are specific to one antigen.
Antibodies are bound to antigens via the variable region (1)
The variable region determines the specificity of the antibody to the different amino acids that it contains, which change the shape of the antigen binding site (1)
A key complication of type 1 diabetes is diabetic ketoacidosis. Explain the process of ketogenesis in the liver. (4 marks)
High rates of fatty acid oxidation result in large amounts of acetyl-CoA
production that exceed the capacity of the Krebs cycle (1)
- 2 molecules of acetyl-CoA are converted into acetoacetyl-CoA by the enzyme thiolase (1)
- Acetoacetyl-CoA is converted into acetoacetate (1)
- This is then converted into b-hydroxybutyrate by b-hydroxybutyrate
dehydrogenase and acetone spontaneously (1)
Name the process of X chromosome inactivation.
Lyonisation
What is the net products of glycolysis
2 ATP, 2NADH, 2H+, 2H2O, 2 pyruvate
Red blood cells are what shape, and why are they this shape? (3)
Biconcave disc (1) to increase the surface area to volume ratio (1) to make
oxygen exchange more efficient (1) / increase the amount of oxygen exchange that can occur at once (1)
What is the average lifespan of a red blood cell? (1)
120 days
Define preload
The initial stretching of the cardiac myocytes (1) prior to contraction (1)
What is afterload? (2)
The pressure the left ventricle must overcome to eject blood (1) during systole / contraction (1)
Define negative chronotropic
Decreases the heart rate
Define negative inotropic
Decreases the contractility
Weakness of which anatomical structure allows reflux of acid into the oesophagus?
The lower oesophageal sphincter
Describe oesophageal innervation in terms of nervous innervation and
voluntary/involuntary action. (3)
Vagus nerve (1)
- Upper portion of the oesophagus has voluntary (striated) fibres (1)
- Lower portion of the oesophagus has involuntary (smooth) fibres (1).
- (The middle third has a mixture of these).
NSAIDs are known to exacerbate GI problems, especially causing peptic ulcers. What is the mechanism of action of NSAIDs? (2)
- Inhibition of COX 1 and COX 2
- Prevents prostaglandin synthesis
- Decreases gastric mucosal protection
- Decreases inflammation
An ulcer on the posterior duodenal wall could erode through, and cause a bleed.
Which artery is most at risk of this?
gastroduoneal artery
What is an important differential diagnosis for retrosternal chest pain? (1)
Myocardial infarction (1)
Previously he had pain in his thoracic spine. Name 3 differences between
appearance of thoracic and cervical vertebrae.
Thoracic vertebrae have inferiorly slanting spinous process AND cervical have bifid spinous processes
- Thoracic vertebrae have costal facets AND cervical do not
- Thoracic vertebrae don’t have transverse foramina AND cervical do
- Thoracic vertebrae have smaller heart shaped vertebral foramen AND cervical
have larger more oval shaped one
Where does the corticospinal tract decussate?
1-2 vertebrae levels above the entry into the spinal cord
In the pathway of CSF flow
i. What cells produce CSF, and where are these located?
Ependymal cells (1) in the choroid plexus (1) of the ventricles
What is the name of the structure connecting the third and fourth ventricles?
Cerebral aqueduct
CSF returns to venous circulation after drainage through dural venous sinuses.
Which vein do all dural venous sinuses drain into?
Internal (1) jugular vein (1)
Lipofuscin is a pigment formed from peroxidation of lipids in older cells.
i. What colour is it?
Orange/brown
Adipose tissue is abundant throughout the body.
i. What are the two types of adipose tissue? (2)
- Brown adipose tissue
- White adipose tissue
ii. One of these types is found down the back and across the shoulders of a newborn child. What is its function? (1)
Thermoregulation
The doctor asks the patient to provide a mid-stream urine sample to investigate the presence of blood that the patient describes. Explain how the process of micturition
occurs. (4)
As the bladder fills with urine, stretch receptors in the bladder wall are
stimulated by the increase in pressure (1)
- Afferent neurons from these receptors enter the spinal cord and stimulate the
parasympathetic pelvic splanchnic nerve causing the detrusor muscle to
contract (1)
- The afferent neurons also inhibit the sympathetic hypogastric nerve to the
internal urethral sphincter and the somatic pudendal nerve to the external
urethral sphincter causing it to relax (1)
- The opening of both sphincters and contraction of the detrusor muscle result in urination (1)
Francis is referred for a renal ultrasound to confirm the diagnosis of PKD. This shows the presence of cysts in the renal cortex and medulla of Francis’ kidneys. Describe the effect that having cysts in the renal medulla may have on Francis’ urinary output.
The loop of Henle of juxtamedullary nephrons extend deep into the renal medulla
- These are responsible for generating an osmotic gradient in the medulla that
functions to reabsorb water
- Cysts in the renal medulla, therefore, causes the patient to produce large
volumes of dilute urine because the loop of Henle is unable to reabsorb water sufficiently
Explain the process of exhalation during exercise.
The activity of motor neurons to the diaphragm decreases at the end of
inspiration causing the diaphragm and external intercostal muscles to relax (1)
- The internal intercostal and abdominal muscles also contract because this is an active process as air is being forced out of the lungs (1)
- This causes the ribs to move downwards and inwards, actively decreasing the thoracic volume and the abdominal contraction forces the relaxed diaphragm further into the thoracic cavity, increasing intrathoracic pressure (1)
- This causes a greater volume to be expired than normal (1)
The patient is diagnosed with COPD and the doctor explains to him that he is progressively not receiving enough oxygen and there is destruction of the capillaries in his lungs.
State the phenomenon that is occurring. (1)
V/Q mismatch OR ventilation-perfusion mismatch (1)
A reduction in oxygen can result in hypoxia. State 2 causes of hypoxia.
Any 2 correct causes i.e. V/Q mismatch, hypoventilation, diffusion impairment,
shunting
Oxygen is transported in the blood via haemoglobin. Explain how the blood carries oxygen with reference to the oxygen dissociation curve. (3)
At high partial pressures of oxygen, haemoglobin binds to oxygen to form
oxyhaemoglobin (1)
- The oxygen dissociation curve is a sigmoid shape because oxygen
cooperatively binds to haemoglobin (1)
- This means that haemoglobin has a greater ability to bind to oxygen after a
subunit has already been bound to oxygen (haemoglobin is most attracted to oxygen when 3 or 4 of the subunits are already bound) (1)
The patient also complains of coughing up small amounts of mucus. Describe how mucus is moved through the airways. (3)
Mucus is transported by air flow and the mucociliary escalator (1) from the
lower respiratory tract to the pharynx (1)
- The mucociliary escalator brings up mucus by the cilia beating in directional
waves up the airways (1)
State the most common type of pulmonary macrophage and explain how these fight infections. (4)
Alveolar macrophages (make up 93% of pulmonary macrophages) (1)
- Alveolar macrophages functions to destroy bacteria swiftly through
phagocytosis where the macrophage engulfs the bacteria within a phagosome
(1)
- The membrane fuses with a lysosome containing hydrolytic enzymes, forming
the phagolysosome (1)
- The lysosome enzymes break down and destroy the bacteria (1)
Trendelenburg sign is produced by observing a positive unilateral pelvic drop.
i. What nerve is affected by this?
ii. What muscles are affected by this?
Superior gluteal nerve
Gluteus medius (1) and gluteus minimus (1)
Define osteoporosis
Low bone density which presents with fractures (T score < -2.5) (1)
Define osteopenia
Decreased bone density (T score -1 > n > -2.5) (1)
Define osteomalacia
Poor bone mineralisation (1)
Which three muscles form the anterior compartment of the upper arm, and what nerve innervates these muscles? (4)
BBC
Biceps brachii
Brachialis
Coracobrachialis
Musculocutaenous
Describe the sliding filament theory of skeletal muscle contraction (6)
Sarcomere contracts via excitation -contraction coupling
Troponin I binds to actin filament, Troponin T binds to tropomyosin and troponin C binds to calcium ions.
Depolarisation of the neuromuscular junction causes an influx of calcium ions into the sarcoplasm from the SR
Calcium ions binds to troponin C, causing a conformational change, which moves tropomyosin away from the myosin head
Myosin forms cross bridge with actin, allowing a power stroke
During the power stroke, the myosin head bends, releasing ADP and phosphate
ATP binds to the myosin head causing it to uncouple from actin, allowing the process to repeat
ATP is hydrolysed to ADP and phosphate, returning myosin to normal position
What happens to FEV1 and FVC measurements in a restrictive lung disease?
Both decrease (1) equally / almost equally / by similar amounts
What is the name of the measurement will Charlotte be taking when she is blowing into this device? (1)
Peak Expiratory Flow Rate (1)
If the GP decided to refer this patient to get transfer estimates (testing how quickly gas is transferred across the alveolar epithelium) what gas would be used and why?
Carbon Monoxide (1) because it has a high affinity for haemoglobin (1)
What main measurement is taken by central chemoreceptors?
PaCO2
Which lung receptors are rapidly adapting and initiate the cough and gasp responses? (1)
- Irritant (1)
Stretch receptors adapt slowly; irritant receptors adapt rapidly; Juxtacapillary or
J-receptors are activated when the pulmonary capillaries are filled with blood.
Briefly describe process of endochondral ossification.
Begins with the creation of hyaline cartilage proformers.
A bony collar is then established around the diaphysis.
Blood vessels penetrate the bony collar and bring in osteoprogenitor cells.
A primary centre of ossification is established. Osteoblasts lay down primary bone.
A secondary centre of ossification is established in the epiphyses.
The amount of cartilage present decreases and is restricted to just to the growth plates.
Briefly describe the process of intramembranous ossification.
Bone is directly deposited into mesenchymal tissue.
Osteoblasts deposit isolated islands of bone until a plate of primary bone has been created.
This primary bone is then replaced with denser, lamellar, secondary bone.
Fracture healing
- Haematoma
1. Bleeding of endosteal and periosteal vessels.
2. Decreased blood flow.
3. Periosteal stripping.
4. Osteocyte death. - Inflammation
1. Fibrin clot organisation.
2. Neovascularisation.
3. Cellular invasion - osteoclasts, mesenchymal stem cells etc. - Repair
1. Callus formation - fibroblasts, chondroblasts and osteoblasts produce fibrous tissue, cartilage and osteoid respectively.
2. Matrix mineralisation.
3. High vascularity. - Remodelling
1. Woven bone is replaced with lamellar bone.
2. Increased bone strength.
3. Vascularity returns to normal.
Give 6 of the Bradford Hill criteria that provide evidence for causation.
Consistency.
Reversibility.
Biological plausibility.
Strength of association.
Temporality - cause before disease.
Dose-response.
What is the definition of perceptual set?
Perceptual set is the psychological factors that determine how we perceive the environment
What are the elements of perceptual set?
contextual
culture
expectations
mood
