PCS 3 Flashcards
What does an increase in collagen in the lungs do to a)compliance
b) elastic recoil?
e. g. excess collagen in fibrosis.
More collagen will DECREASE compliance (making it harder to inflate the lungs) INCREASE elastic recoil
Name some upper motor neurone symptoms.
- high muscle tone (hypertonia)
- pyramidal pattern of weakness
- lack of fasciculations
- no muscle wasting
- exaggerated reflexes (hyper reflexia)
- abnormal plantar reflex (toes point up instead of down) = +ve Babinski reflex
Name some lower motor neurone symptoms.
- loss of muscle tone / flaccid muscles (hypotonia)
- focal pattern of weakness (often starting at the peripheries)
- fasciculations
- muscle wasting (muscles aren’t being innervated)
- weak or absent reflexes (hyporeflexia)
- absent or normal plantar reflex
Go through the pathway for Gq.
Phospholipase C is activated.
It acts on PIP2 to create DAG and IP3.
DAG activates PKC. IP3 activates calcium channels causing calcium efflux from intracellular stores.
What is a Telocentric chromosome?
Centromere is located at the terminal end of the chromosome.
What is a Subtelocentric chromosome?
Centromere is located closer to its end than to its center.
What is a Metacentric chromosome?
Centromere is in the middle .
Which branch of which cranial nerve provides sensory innervation to the cornea for the blink reflex?
Ophthalmic nerve of Trigeminal (CN V)
Go through the steps of Vitamin B12 absorption.
- Binds to Haptocorrin (protecting it from being attacked by the low PH of the gastric juice)
- Haptocorrin is degraded in the duodenum, releasing Vitamin B12
- B12 binds to an Intrinsic Factor in the duodenum secreted by parietal cells.
- The VB12:IF complex is absorbed in the lower ileum (calcium dependent)
- After release from the Intrinsic Factor, Vitamin B12 binds to Transcobalamin 2, where it is then absorbed into the blood.
The levator palpebrae muscle has two components. What are they? What do they do? What happens if each of them is damaged?
Striated - supplied by Occulomotor. Elevates the upper eyelid. Damage: unable to elevate the upper eyelid.
Smooth - ‘superior tarsal muscle’. Supplied by the sympathetic chain. Elevates the upper eyelid. Damage: ptosis (drooping of upper eyelid)
Name the cranial nerve that only contains motor fibers?
Abducent nerve. Only supplies motor innervation to the lateral rectus.
What is the role of Aldosterone?
Increases NaCl re absorption
Increases H20 re absorption
K+ excretion
What is the role of Atrial natriuretic Peptide?
Decreases NaCl re absorption
What is the role of Parathyroid Hormone?
Decreases phosphate absorption
Increases calcium absorption
What is the role of ADH?
Increases H20 re absorption
What is the role of Angiotensin II?
Increases NaCl (causes release of aldosterone from adrenal cortex)
H20 re absorption (stimulates ADH release)
H+ secretion
Vasoconstriction of efferent arteriole
What cranial nerve innervates the orbicularis oculi muscle? What does this muscle do?
Facial (VII)
Closes the eyelids.
What is Addison’s disease?
Adrenal cortex HYPOfunction.
What is the action of Tropicamide?
mACH antagonist. Blocks parasympathetic innervation.
Results in:
- Dilation of the pupil.
- Loss of function of ciliary muscle and sphincter pupillae
- Loss of close focusing on objects.
What stimulates the release of Secretin?
Low pH.
Secretin stimulates the release of a bicarbonate rich fluid from the duct cells.
Name the boundaries for Hesselbach’s Triangle.
lateral wall - inferior epigastric artery
medial wall - rectus abdominis muscle
floor - inguinal canal
Most common place for a DIRECT inguinal hernia as the hernia is medial to the inferior epigastric vessels.
What occurs during the Proliferative phase of the uterine cycle?
Oestrogen is being secreted by follicles leading to endometrial growth and thickening.
Glands are developing but not producing anything.
What occurs during the Secretory phase of the uterine cycle?
Corpus luteum has been formed and secretes progesterone and oestrogen.
Progesterone stimulates the uterine glands to secrete glycogen, providing a favourable uterine environment for implantation. Cork screw shaped.
Stratum functionalis is very thick and vascularised (spiral arteries)
What occurs during the Menstrual phase of the uterine cycle?
When CL has regressed, there is no progesterone being produced so shedding of endometrium (S. Funct) occurs.
Menses - bleeding from constricted spiral arteries.
Rising FSH and LH (not inhibited anymore)
Name three ways to inhibit gastric juice secretion.
Low pH in the stomach (acid)
Secretion of secretin by S-cells / CCK by I cells
Secretion of GIP
Name four functions of Sertoli cells.
- Creates seminiferous tubules.
- Supports spermatogenesis.
- Produces ABP and Inhibin.
- Converts Testosterone –> DHT / Oestrogen.
What is the only vitamin or mineral currently recommended for supplementation by the NHS?
Folic Acid (B9) during pregnancy. A lack of vitamin B9 during embryonic development can lead to spinal tube defects.
Name the cranial nerves WITH parasympathetic fibres.
oculomotor (CNIII)
facial (CNVII)
glossopharyngeal (CNIX)
vagus (CNX)
Name the cranial nerves (1 -12)
Do they have sensory or motor function? (or both?)
I – Olfactory - S
II – Optic - S
III – Oculomotor - M
IV – Trochlear - M
V – Trigeminal - S&M
VI – Abducent - M
VII – Facial - S&M
VIII – Vestibulocochlear - S
IX – Glossopharyngeal - S&M
X – Vagus - S&M
XI – Accessory - M
XII – Hypoglossal - M
Name the hormones from the hypothalamus that control the release of Growth Hormone in the anterior pituitary.
GHRH (+) Somatostatin (-)
Name the nerves passing through Internal Acoustic Meatus.
Facial Nerve
Vestibulocochlear nerve
Name the nerves passing through Jugular Foramen.
Glossopharyngeal, Vagus, Accessory Nerves
Internal Jugular Vein
Name the nerves passing through Superior Orbital fissure.
Ophthalmic Branch of the Trigeminal, Oculomotor, Trochlear and Abducens Nerves
Superior Ophthalmic Vein
Damage to which nerves cause ‘claw hand’ and ‘hand of benediction’?
Claw Hand = ulnar
Hand of benediction = median
Go through the pathway for Gs.
Adenylyl cyclase is activated.
This causes ATP to be converted to cAMP. c
AMP activates PKA.
What G protein does Glucagon act through? Go through the pathway.
Gs.
- Adenylyl cyclase is activated.
- This causes ATP to be converted to cAMP.
- cAMP activates PKA.
- PKA activates phosphorylase kinase which activates glycogen phosphorylase.
- Glycogen phosphorylase is converted into phosphorylase A which converts Glycogen to Glucose **required when glucose levels are low**
What is released from the adrenal medulla? Stimulation for release?
Adrenaline & Noradrenaline
Sympathetic stimulation - AcH (from pregaglionic neurone)
What is released from
a) Zona glomerulosa
b) Zona fasiculata
c) Zona reticularis
a) Aldosterone
b) Cortisol
c) Androgens - DHEA, DHEAs, DHT
What hormones change the viscosity of cervical mucus a) prior to ovulation ?
b) after ovulation ?
A) High levels of oestrogen reduce the viscosity to allow sperm to enter.
B) High levels of progesterone increase the viscosity to prevent more sperm from entering.
When does the secondary oocyte complete meiosis II?
At fertilsation
Where are RBC are phagocytosed?
In the spleen by macrophages or …
In the liver kupffer cells in the liver
Name the snare proteins.
Syntaxin and SNAP25 (T snare proteins)
Synaptobrevin and Synaptomagin (V snare proteins)
Out of the five eye drugs, which one is a mAcH agonist?
Pilocarpine
What is the function of ..
superior oblique & inferior oblique?
SO - depression and ABDuction
IO - elevation and ABDuction
What is the function of ..
Superior rectus
Inferior rectus
Medial rectus
Lateral rectus ?
SR - elevation and ADDuction
IR - depression and ADDuction
MR - adduction and medial rotation
LR - abduction and lateral rotation
How does Noradrenaline cause contraction in cardiac muscle?
(include what G protein it is linked to and the pathway involved)
Acts on b1 / b2 receptors.
b1&2 receptors in cardiac muscle linked to Gs (cAMP cascade is activated which activated PKA).
It phosphorylylates L type calcium channes - “Ca2+ INDUCED”.
This causes calcium channels on the sarcoplasmic reticulum - Ca2+ release =
Contraction
What is the action of the Gq receptor being activated in a smooth muscle cell?
Gq is linked to a1 receptor.
IP3 generated from PIP2 causes calcium release from intracellular stores.
This leads to CONTRACTION of the smooth muscle.
What is the action of the Gs receptor being activated in a smooth muscle cell?
Linked to b2 receptor. Adenylyl cyclase is activated - cAMP formed which activates PKA.
PKA inhibits MLCK.
This causes smooth muscle RELAXATION.
What is the action of the Gi receptor being activated in a smooth muscle cell?
Gi inhibits adenylyl cyclase.
No cAMP is produced and PKA is NOT activated.
This causes MLCK to become activated =
CONTRACTION.
How does Nitrogen Oxide affect MLCP in smooth muscle?
It activates Guanylyl cyclase.
This converts GTP –> cGMP.
The rise in cGMP
1) activates PKG which prevents calcium from entering the cell.
2) activates MLCP which detatches cros bridges / causes relaxation.
How does Rhokinase affect MLCP in smooth muscle?
It is stimulated by activation of the Gq protein.
Rhokinase inhibits MLCP therefore leading to
smooth muscle CONTRACTION.
Prazosin is an alpha 1 adrenorecepter antagonist.
a) What G protein is it linked to?
b) what is its mechanism of action?
a) Gq
b) Blocks Gq receptor so reduces the IP3 production. This prevents smooth muscle contraction (as no calcium is released) and leads to dilation of blood vessels.
What is the difference between a metabotropic and ionotropic receptor?
Metabotropic = they do not have a channel that opens or closes. Instead, they are linked to a G-protein.
Ionotropic = transmembrane molecules that can open or close a channel, Activated by a ligand.
How does Noradrenaline cause smooth muscle relaxation?
Via Beta-2 receptors:
activates Gs which leads to an increases in cAMP and Protein Kinase A which inactivates Myosin Light Chain Kinase
Calmodulin is a calcium binding molecule. How many binding sites does it have for Ca2+?
4 binding sites.
What is the equation for calculating the rate of IV infusion?
(total volume (ml))/total time (hours)
x drip factor of set/60
What are the three stages in which differentiation occurs?
- Specification: fate is not absolute, cell identity is still subject to change
- Determination: fate is fixed and cannot be changed in response to the environment
- Differentiation: change in cell structure and function —expression of genetic coding
What makes up the Philadelphia chromosome?
Reciprocal translocation between chromosome 9 and 22 which gives rise to bcr-abl gene
What is a robertsonian translocation?
A robertsonian translocation is the fusion of long arms of acrocentric chromosomes (the ones with a very short p arm). This means that the short arms are lost
Function of
a) Juxtaglomerular cells?
b) Macula densa cells?
a) secrete renin
b) detect NaCl concentration - stimulate release of ADH and aldosterone in response.
Difference between
a) reciprocal translocation
b) roberstonian translocation
c) philadeplhia chromosome
a) exchange of material between non homologus chromosomes e.g. 1 & 2
b) fusion of long arms of acrocentric chromosomes and loss of short arms
c) Reciprocal translocation between between 9 and 22.
BCR-ACL fusion protein formed.
Go through the sequence of neurones in the spinothalamic tract.
What sensations does it carry?
First neurone synapses in dorsal horn with second order neurone. 2nd order neurone cross over at the dorsal dorn to the opposite side. This tract ascends to the thalamus and synapes with a third order neurone. 3rd order neurone projects to the somatosensory cortex.
Crude touch, pain and temperature.
Go through the sequence of neurones in the dorsal column.
What sensations does it carry?
First neurone enters the dorsal horn and ascends on the same side of the spinal cord until it reaches the medulla. At the medulla, it synapses with a second order neurone which crosses over the opposite side and ascends to the thalamus were it synapses with a third order neurone. 3rd order neurone projects to the somatosensory cortex.
Fine touch, proprioception and vibration.
What is meant by the term ‘wind up’?
Prolonged stimulation of ‘c’ fibres leads to a rise in the amount of substance P in the dorsal horn.
What is the difference between
Allodynia?
Hyperalgesia?
Alodynia: triggering of a pain response from A-beta fibres which do not normally provoke pain. Temperature or physical stimuli can provoke allodynia, which may feel like a burning sensation, and it often occurs after injury to a site.
Hyperalgesia: an increased sensitivity to pain, which may be caused by damage to nociceptors or peripheral nerves.
Ascending pain and temperature fibres send information to the PAG. Stimulation of the PAG matter activates …?
enkephalin-releasing neurons that project to the raphe nuclei in the brainstem.
These release serotonin which activates inhibitory interneurons in the dorsal horn.
The interneurons can inhibit the release of substance P from A-delta and C fibres, which inhibits activation of the second order neurone responsible for carrying the pain signal up to the thalamus.
What would cause renal inulin (or creatinine) clearance to increase?
dilation of the afferent arteriole and
constriction of the efferent arteriole
This would increase glomerular capillary hydrostatic pressure and thus increase GFR. - higher amount of filtrate produced! (Note that inulin (or creatinine) clearance is a measure of GFR).
What is the rate limiting step for synthesis of various steroids from cholesterol?
Transport of free cholesterol from the cytoplasm into the mitochondria
What is the equation involving pH, log and H+?
pH = - log [H+]
What is the equation for net filtration pressure in the glomerulus?
What equation requires you to calculate NFP?
Net filtration pressure =
Glomerular hydrostatic pressure
- Bowmans capsule pressure - Glomerular oncotic pressure
GFR = NFP x Kf
What is the Modification of Diet in Renal Disease (MDRD) equation used for?
What variables does it take into account?
estimating GFR
Age, Gender, Ethnicity, Creatinine
(not! weight or height)
What does activation of B1 on the kidneys do?
Acts on Juxtoglomerular apparatus to secrete renin
Descending pathways.
Medial and Lateral.
What do they control?
Medial = posture, balance, proximal muscles.
Lateral = fine skilled movements, distal muscles.
What is the action of the drug ‘Curare’?
blocks nicotinic receptors at the neuromuscular junction
What is the effect of PYY (peptide tyrosine tyrosine) on the PNS and CNS in terms of appetite?
PNS - reduces appetite
CNS - increases appetite
Secreted from L cells of duodenum.
Which efferent fibers are responsible for the basal level of tone that predominates in most vascular beds?
Sympathetic vasconstrictor fibres
