Week 4 Flashcards
(137 cards)
1
Q
Give the 6 steps to cell-to-cell communication.
A
1- synthesis of signal
2- release of the signaling molecule by the signalling cell
3- transport of the signal to the target cell
4- detection of the signal by a specific receptor protein
5- change in cellular metabolism/function/development triggered by the receptor-signal complex
6- removal of the signal or desensitisation
2
Q
Give one example of and describe endocrine, paracrine, autocrine transmission, neurotransmission, and membrane-bound transmission.
A
ENDOCRINE
hormone released by endocrine cell and carried in bloodstream to distal target cells
example: FSH released from pituitary, acting upon ovary
PARACRINE
signalling molecules only affect target cells in close proximity to secreting cells
example: stomatostatin released by pancreas cells
NEUROTRANSMISSION
can be considered as either a long-range or a type of paracrine signalling
example: phrenic and thoracic nerves to the diaphragm
AUTOCRINE
cells respond to substances that they themselves release
example: some neurotransmitters and growth factors (TGF), insulin
MEMBRANE-BOUND
Plasma membrane-attached proteins can interact to signal
example: T-cells in the immune system
3
Q
Give one example of multiple types of signalling occurring simultaneously.
A
insulin
4
Q
Which signalling molecules can enter the cell to bind to intracellular receptors? Give 4 examples belonging to the same family of molecules, and name this family.
A
lipid soluble signalling molecule
STEROID HORMONES:
- cortisol
- estradiol
- testosterone
- thyroxine
5
Q
Signalling for altered protein function and signalling for altered protein synthesis have different timescales. Outline.
A
ALTERED PROTEIN FUNCTION
fast: less than seconds to minutes
ALTERED PROTEIN SYNTHESIS
slow: minutes to hours
6
Q
What does an activated receptor-cortisol complex do?
A
binds to the regulatory region of target gene and activates transcription
7
Q
Describe the inositol phospholipid signalling pathway to activation of a PKC molecule.
A
- signal molecule binds to a G-protein-linked receptor
- activated G-protein alpha subunit activates phospholipase C (PLC) in cytosol
- PLC catabolises inositol phospholipid (PIP2) into inositol 1,4,5,-triphosphate (IP3) and diacylglycerol (DAG)
4a. DAG stays embedded in membrane
4b. IP3 opens a calcium channel in the endoplasmic reticulum membrane - protein kinase C (PKC) is activated by calcium freed by IP3 and binds to the cytoplasmic leaflet of membrane onto DAG
- PKC performs function
- IP3 and DAG are recycled back to membrane as PIP2
8
Q
Give three examples of PKC substrates and explain what their function is.
A
p53 (transcription factor) –> prevents tumour formation
Ca(V) 1.2 –> calcium channel involved in heart muscle contraction
IKKalpha –> cytokine involved in B cell activation (immune function)
9
Q
Define eicosanoids, give one other name for them, and name 3 main families. What is their main source?
A
= prostanoids
inflammatory mediators that act as local hormones: they have specific autocrine/paracrine functions, and are rapidly degraded so they are not transported to distal sites within body
prostaglandins, thromboxanes, leukotrienes
main source: arachidonic acid
10
Q
Describe the eicosanoid biosynthesis pathway.
A
- PLA2 (rate-limiting enxyme) activated by serotonin receptors, glutamate receptor 1, some cytokine receptors, increase in intracellular [calcium]
phospholipids —(PLA2)—> arachidonic acid + platelet-activating factor (PAF)
2a. arachidonic acid —(lipoxygenase)—> hydroperoxy and hydroxy fatty acids —> leukotrienes
2b. arachidonic acid —(cyclooxygenase)—> endoperoxidases –> prostaglandins, prostacyclins OR thromboxane A2 (TXA2)
11
Q
What functions do prostaglandins regulate?
A
- vasoconstriction or vasodilationa and inhibition or promotion of platelet aggregation, depending on the receptor
- inflammatory response, thermoregulation (fever), pain
12
Q
Where is TXA2 synthesised? What are its two main roles?
A
- synthesised in platelets
- prothrombotic properties: stimulates platelet aggregation, vasoconstricor
13
Q
Which type of leukotrienes is heavily involved in anaphylactic shock?
A
leukotrienes that contain a cysteine amino acid in their structure
14
Q
Where are platelet-activating factors synthesised and what are their roles?
A
synthesised in neutrophils, basophils and platelets and in injured tissue
- platelet aggregation
- vasoconstriction
- inflammation
- immune response (including anaphylaxis)
15
Q
What is the mechanism of action of ibuprofen?
A
block the hydrophobic channel by which arachidonate acid enters the cyclooxygenase active site
- -> competitive inhibitor of cyclooxygenase
- -> inhibit formation of prostaglandins (no fever, pain or inflammation) and inhibit thromboxane formation in platelets (no blood clotting)
16
Q
What is the mechanism of action of aspirin?
A
aspirin acetylates a serine hydrocyl group near the active site of cyclooxygenase, preventing arachidonate binding –> irreversible inhibition
17
Q
Why is aspirin anti-clotting effect long-lived?
A
aspirin irreversibly prevents the formation of thromboxane in blood platelets.
Platelets lack a nucleus –> cannot make new cyclooxygenase
18
Q
Give the full name of NSAIDs
A
Non-steroidal anti-inflammatory drugs
19
Q
Define reflex. Give one example of reflex with conscious awareness and one without.
A
a specific, involuntary, unpremeditated, ‘built-in’ response to a particular stimulus
with conscious awareness: temperature, hunger…
without conscious awareness: BP…
20
Q
Describe the reflex arc, from the arrival of a stimulus.
A
stimulus –> receptor —(afferent pathway)—> integrating center compares to a set point —(efferent pathway)–> effector –> response (sometimes –> negative feedback back to receptor)
21
Q
Give two examples of reflex arc where negative feedback is respectively present and absent.
A
NEGATIVE FEEDBACK: temperature
NO NEGATIVE FEEDBACK: secretion of acid in the stomach at the smell of food
22
Q
Give the conduction velocity and diameter of the nerve fibre types classified according to their conduction velocity. Give two factors on which conduction velocity depends.
A
A-alpha:
70-120 m/s
12-29 micrometers
A-beta:
30-70 m/s
5-12 micrometers
A-gamma:
15-30 m/s
3-6 micrometers
A-delta:
12-30 m/s
2-5 micrometers
B:
3-15 m/s
1-3 micrometers
C:
- 5-2 m/s
- 1-2 micrometers
DEPEND ON : myelination and diameter
23
Q
Give the functions of each fibers based on their sensory function, and give their equivalent based on conduction velocity.
A
IA:
muscle spindles
A-alpha
IB:
Golgi tendon organs
A-alpha
II:
muscle spindles, touch and pressure receptors
A-beta and A-gamma
III:
pain and temperature receptors
A delta
IV:
pain and other receptors
C
24
Q
What type of nerve fibers do alpha motor neurons belong to?
A
A-alpha
25
What does the spectrum of motor unit sizes within a given muscle depend on?
- the precision of control required
| - the force of contraction required or a low precision
26
What two factors control muscular contraction?
- alterations in the frequency with which any single motor neuron fires action potentials
- recruitment of alpha motor neurons
27
How come muscle reflexes can be used for diagnosis?
they produce a stereotyped response to a given stimulus
28
Differentiate between intrasegmental and intersegmental reflexes.
INTRASEGMENTAL
the reflex arc is restricted to one or two spinal segments
INTERSEGMENTAL
the reflex arc involves a number of spinal cord segments
29
Describe the muscle reflex time components.
1. activation of sensory receptors
2. conduction to CNS along nerve fibers from receptors
3. transmission across neuron/neuron synapses in CNS
4. conduction from CNS along nerve fibres to muscle
5. activation of muscle contractile machinery
30
What are muscle spindles? Distinguish between the two types
stretch receptors (peripheral nerve endings), wrapped around intrafusal muscle fibers that are embedded in muscle, that monitor length and rate of change in length
CHAIN FIBERS
- both IA (rate of change) and II (total length) sensory nerve fibres
- most common type
- fibres nuclei are arranged in a chain in the central portion
BAG FIBRES
- IA only (rate of change)
- only 1 or 2 per spindle
- swelling in the equatorial region which houses the nuclei
31
What is the rate of firing of muscle spindles determined by?
- magnitude of stretch
| - speed of stretch
32
Why are gamma motor efferent neurons activated for in muscle spindle functioning?
to prevent the loss of sensation of spindle when most compressed
33
Describe the mechanism of reciprocal innervation.
1. influence on spindle sensory fibres from homonymous muscle on motor neurones projecting to antagonist muscles (disynaptic reflex)
2. effect is opposite to that on their own muscle:
3. relaxes antagonist muscles and facilitates shortening of homonymous muscle
4. requires the involvment of a local inhibitory neuron in the reflex onto the antagonist muscles
34
What type of sensory fibres innervate Golgi tendon organs? What are their actions on alpha motor neurons to the muscle?
mechanosensitive IB
as tension develops, GTO increase their rate of firing and so increase the inhibition to the alpha motor neuron, consequently reducing the tension in the muscle
35
What is the integrating center for the baroreceptor reflex?
medullary cardiovascular centre
36
Through which gateway does the axillary nerve go through?
quadrangular space
37
What are the innervations of the axillary nerve?
- skin over lower part of deltoid
- deltoid
- teres minor
38
Which roots is the radial nerve associated with?
C5-T1
39
Which branch of which nerve pierces the supinator muscle?
deep branch of radial nerve
40
List the 13 muscles the radial nerve supplies?
- triceps
- anconeus
- brachioradialis
- supinator
- abductor pollicis longus
- extensor carpi radialis brevis
- extensor carpi radialis longus
- extensor carpi ulnaris
- extensor pollicis brevis
- extensor pollicis longus
- extensor digitorum
- extensor indicis
extensor digiti minimi
41
Which structures does the musculocutaneous nerve (C5-7) supply?
- skin on anterolateral side of the forearm
- biceps
- brachialis
- coracobrachialis
42
Which structures does the median nerve travel with in the arm?
- ulnar nerve
| - brachial artery
43
Which tendons accompany the median nerve in the carpal tunnel?
- Flexor digitorum superficialis,
- flexor digitorum profundus,
- flexor pollicis longus
44
Name the 11 muscles the median nerve supplies.
- flexor digitorum superficialis
- flexor carpi radialis
- lateral part of flexor digitorum profundus
- pronator quadratus
- pronator teres
- flexor pollicis longus
- flexor pollicis brevis
- abductor pollicis brevis
- opponens pollicis
- lateral 2 lumbricals
45
Name the 15 muscles innervated by the ulnar nerve.
- flexor carpi ulnaris
- medial part of flexor digitorum profundus
- opponens digiti minimi
- flexor digiti minimi
- abductor digiti minimi
- adductor pollicis
- medial 2 lumbricals
- dorsal interossei
- palmar interossei
46
What are the 3 most probable causes of an axillary nerve injury?
- fracture of the surgical neck of the humerus
- subglenoid dislocation of humeral head towards quandrangular space
- quadrangular/quadrilateral space syndrome
47
What would be the clinical findings of a radial nerve injury?
- sensory loss, depending on where the lesion is situated
- wrist drop (weakness/loss of hand extension)
- weakness in/loss of extension of thumb
- weakness in/loss of extension of metacarpophalangeal joints
48
Give the causes and clinical finding of a musculocutaneous nerve injury.
CAUSES
penetrating injuries to the axilla/proximal medial arm
CLINICAL FINDINGS
- paresthesia over lateral forearm
- weakness in flexion of GH joint
- very weak or loss of flexion of elbow joint
- weakness in supination
49
Give 4 causes of median nerve injury.
- elbow dislocation
- supracondylar fracture of humerus
- anterior dislocation of lunate
- compression in carpal tunnel
50
Give the areas for physical exam of the median nerve
- pad of index
| - asking the patient to oppose the thumb
51
What is an ulnar claw?
results from an ulnar nerve injury
4th and 5th fingers:
- MCP joints hyperextended
- IP joints flexed
52
Give two causes for Erb's paralysis
- high energy trauma
| - obstetric injury during birth
53
What would the clinical findings for Klumpke's palsy be?
- paralysis of intrinsic muscles of the hand, flexors of wrist and fingers, forearm pronator
- loss of sensation to medial forearm and little finger
- ulnar claw hand
54
Give 5 signs of lower motor neurone disorders, and 3 of upper motor neurone disorders.
LOWER MOTOR NEURONE DISORDER
- flaccid paralysis
- atrophy
- fasciculation
- decreased muscle tone
- loss of tendon reflexes
UPPER MOTOR NEURONE DISORDER
- spasticity
- exaggerated tendon reflexes
- Babinski sign
55
Define spasticity.
a condition in which affected muscles are continuously contracted, causing stiffness or thightness and possibly hindering gait, movement and speech
symptoms: hypertonicity, clonus, exaggerated deep tendon reflexes, muscle spasms
56
Give the definition and 7 early symptoms of hypovolaemic shock.
= a clinical state in which tissue perfusion is inadequate due to a loss of blood. A reduction in blood volume causes a fall in systolic BP and reduced blood flow to tissues and the peripheries.
- tachycardia
- skin pallor
- hypotension
- confusion, aggression, drowsiness, coma
- general weakness
- thirst
- reduced urine output
57
Estimate the blood loss in liters caused by the following fractures: humerus, tibia, femur, pelvis.
Give 6 factors where the degree of bloodloss may be missinterpreted because of altered physiologic responses.
HUMERUS: 0.5-1.5L
TIBIA: 0.5-1.5L
FEMUR: 1.0-2.5L
PELVIS: 1.0-4.0L
FACTORS
- elderly population
- certain medications: beta-blockers, antihypertensives, antianginals
- pacemakers
- athletes
- pregnancy
- hypothermia
58
In which of fracture or bleeding management do you NOT elevate the limb?
fracture management
59
Which 3 parts of the nervous system form the autonomic nervous system?
- visceral sensory
| - visceral motor: parasympathetic + sympathetic
60
Distinguish between pre- and postganglionic fibers (length, origin) of the parasympathetic and sympathetic system.
SYMPATHETIC
- short preganglionic fibers from thoracolumbar region of the spine
- long postganglionic fibers from paravertebral chain or prevertebral ganglia
PARASYMPATHETIC
- long preganglionic fibers from craniosacral areas
- short postganglionic fibers from within or near the target organ
61
What are the 4 'options' a preganglionic neuron can follow in the sympathetic nervous system?
- can ascend the paravertebral chain and synapse in a superior ganglion
- can stay at the same level and synapse in the ganglion
- can descend the paravertebral chain and synapse in an inferior ganglion
- can access to the prevertebral ganglia and synapse there
62
Name the 3 sympathetic prevertebral ganglia from superior to inferior.
- celiac ganglion
- superior mesenteric ganglion
- inferior mesenteric ganglion
63
Differentiate between mydriasis and myosis.
MYDRIASIS
dilation of pupil by pupillary dilator muscle
sympathetic innervation only
MYOSIS
contraction of pupil by pupillary constrictor muscle
parasympathetic innervation only
64
Where would you find nicotinic ACh receptors in the ANS? And muscarinic ACh receptors?
nAChR
- preganglionic synapse to postganglionic neurons (both sympathetic and parasympathetic)
- sympathetic neuron synapse to adrenal medulla
mAChR
- sympathetic postganglionic synapse to sweat glands
- parasympathetic postganglionic synapse to tissue
65
What neurotransmitter is used by the sympathetic nervous system to innervate blood vessels?
noradrenaline
66
Give the effects of parasympathetic and sympathetic innervation on: the heart, the lungs, the male sexual organs, the salivary glands, pilomotors.
HEART
- sympathetic increases heart rate and force of contraction
- parasympathetic decreases heart rate
LUNGS
- parasympathetic for bronchoconstriction
- sympathetic for bronchodilation
MALE SEXUAL ORGANS
- parasympathetic: erection
- sympathetic: ejaculation
SALIVARY GLANDS
increased secretion for both
PILOMOTORS
only innervated by sympathetic: piloerection
67
Give three transmission pathways for bloodborne pathogens.
- direct contact with infected fluids
- infection via contaminated needles, syringes, or other unsterilised equipment
- direct infection into the bloodstream by arthropod vectors
68
Give the family and genus of HIV.
retroviridae lentivirus
69
Give 5 viral features of HIV.
- retrovirus --> reverse transcriptase
- spherical (80-100nm)
- enveloped
- highly antigenic surface proteins (env gp 120, ...)
- RNA genome
70
Give the 6 steps of progression to AIDS
exposure to HIV --> seroconversion --> asymptomatic --> persistant generalised lymphadenopathy --> AIDS-related clinical features --> AIDS
71
Give three different types of treatment for AIDS
- nucleoside reverse transcriptase inhibitors
- non-nucleoside reverse transcriptase inhibitors
- protease inhibitors
72
What does HAART stands for? What can it be shortened to?
HAART --> highly active anti-retroviral therapy
ART
73
Name two tests used in diagnosis of HIV-specific antibodies?
- ELISA
| - Western Blotting
74
Name and give one feature for each of three different antigens of HBV.
HBsAg
- indicates infectivity
- anti-HBsAg provides immunity, but appears late
HBcAg
- appears early in infection
HBeAg
- indicates high transmissibility
75
What is the incubation period of HBV?
up to 6 months
76
What is the main difference between acute and chronic HBV infection?
no anti-HBsAg produced in patients with chronic HBV
77
What are the clinical features of pre-icteric HBV?
- malaise
- anorexia
- nausea
- tender liver (pain in right upper quadrant)
78
What causes jaundice?
hyperbilirubemia
79
What are the viral features HCV?
- flavivirus
- single-stranded RNA genome
- enveloped
- replicates primarily in hepatocytes_ destroys liver cells
- cannot be cultured
80
Give the clinical features of HCV infection.
- usually asymptomatic
- fatigue
- nausea
- weight loss
- rarely progresses to cirrhosis
- small proportion may develop hepatocellular carcinoma
81
Which two medication give very good results when used in combination to treat an HCV infection?
ribavirin + peginterferon
82
Name the 5 species of the Plasmodium genus which cause malaria.
- P. falciparum
- P. vivax
- P. ovale
- P. malariae
- P. knowlesi
83
Which arthropod is responsible for the transmission of malaria?
Female Anopheles mosquito
84
Differentiate bewteen sporozoite, hypnozoite and gametocyte, relative to malaria.
SPOROZOITE
injected by mosquito into blood stream
HYNOZOITE
lies dormant in the liver but can be reactivated and return to cycle
GAMETOCYTE
taken by mosquito in saliva when drinking blood
85
Give 3 examples of complications from P. falciparum infection.
- cerebral malaria
- circulatory shock
- hepatitis
86
Give 4 preventive steps against malaria.
- sleep under bed nets
- cover exposed skin between dusk and dawn
- use of mosquito repellants
- prophylaxis
- vaccines in development
87
Which structures does the superior gluteal nerve supply?
- gluteus medius
- gluteus minimus
- tensor fascia latae
88
Through which gateway does the inferior gluteal nerve exit the pelvis?
the infrapiriform space
89
Give the roots of sciatic nerve
L4-S3
90
Outline the branching of the sciatic nerve
sciatic (L4-S3) --> common fibular (L4-S2) + tibial (L4-S3)
common fibular --> lateral sural cutaneous branch + deep fibular (L4-5) + superficial fibular (L5-S2)
tibial --> medial sural cutaneous branch + medial plantar + lateral plantar
medial sural cutaneous branch + lateral sural cutaneous branch --> sural nerve
91
Which muscles of the thigh does the sciatic nerve innervate?
hamstrings: biceps (short head by common fibular nerve and long head by tibial nerve), semitendinosus (tibial nerve), semimembranosus (tibial nerve)
92
Which branch does the common fibular nerve give off before winding around the neck of the fibula?
lateral sural cutaneous branch
93
Which muscles does the deep fibular nerve supply?
- tibialis anterior
- extensor hallucis longus
- extensor digitorum longus, including fibularis tertius
- extensor digitorum brevis
- extensor hallucis brevis
94
Which nerve innervates the lateral compartment of the thigh? What are its root values?
superficial fibular nerve (L5-S2)
95
Which muscles does the tibial nerve supply?
- plantaris
- popliteus
- gastrocnemius
- soleus
- tibialis posterior
- flexor hallucis longus
- flexor digitorum longus
96
Describe the sensory innervation of both medial and lateral plantar nerve.
MEDIAL
anterior 2/3 of the sole + adjacent surfaces of medial 3.5 toes
LATERAL
lateral side on anterior 2/3 of sole + adjacent plantar surfaces of lateral 1.5 digits
97
Give one physiological and one surgical use to the sural nerve.
PHYSIOLOGICAL USE
supplies the skin on lower posterolateral surface of leg, lateral side of foot and little toe
SURGICAL USE
nerve graft
98
Which nerve goes through the retro-inguinal space?
femoral nerve (L2-4)
99
Which muscles does the femoral nerve supply?
- quadratus femoris
- sartorius
- pectineus
- iliacus
100
Which vein accompanies the saphenous nerve?
the greater saphenous vein
101
What kind of nerve is the saphenous nerve?
sensory nerve only
102
Which balanced position is not attainable by someone with a superior gluteal nerve injury? What kind of gait does this lead to?
standing on one foot, with the foot in the air being on the contralateral side to the injured nerve
waddling gait
103
In which two categories of people is sciatic nerve injury due to compression most common?
- athletes
| - women
104
Give three causes of a common fibular nerve injury.
- fibular fracture
- direct trauma
- dislocation of the knee joint
105
What kind of nerve injury does a slap/steppage gait denote?
deep fibular nerve injury
106
What would the clinical findings for superficial fibular nerve injury be?
- paresthesia/anesthesia along anterolateral side of leg and dorsum of ankle and foot
- loss of function of muscles in lateral compartment of leg --> loss of evertion
107
What can be done in total hip replacement surgery to ensure that the obturator nerve does not get damaged?
pay attention to patient positioning
108
About how many kinases and phosphatases does the human genomes code for?
520 kinases
| 120 phosphatases
109
What are the two main types of kinases? What type of reactions do kinases catalyse?
- tyrosine kinase
- serine/threonine kinase
phosphorylation
110
What are the 3 components of G-protein pathway?
- receptor
- G-protein
- effector enzyme (amplifier)
111
How many alpha helices does the G protein coupled receptor have?
7
112
Describe the mechanism of action of a GPCR.
binding of ligand to receptor --> change in conformation of receptor --> in G alpha GDP is displaced and replaced by GTP --> dissociation of G beta-gamma subunit --> activation of downstream pathways
short-lived activation:
GTP is hydrolysed to GDP --> reassociation of G alpha with G beta-gamma --> inactivation of effector enzyme
113
How many G alpha proteins are coded for by the human genome? Name three and give their respective functions.
20 G alpha
Gq --> stimulates phospholipase C
Gs --> stimulates adenylate cyclase, increases cAMP
Gi -->inhibits adenylate cyclase, decreases cAMP
114
Give 4 roles of the G beta-gamma dimer, and state how many combinations are possible.
72 combinations
roles:
- gate ion channels
- stimulates PLA2
- stimulates adenylate cyclase
- stimulates phospholipase C-beta, epsilon and eta
115
Name 3 cellular processes that are activated by the intracellular calcium concentration increasing, and their time domain.
- exocytosis (microseconds)
- contraction (ms)
- metabolism (s)
- gene transcription (min)
- fertilization (hr)
- proliferation (hr)
- hypertrophy (hr)
116
Which two molecules can activate protein kinase C (PKC)?
membrane-associated DAG and/or calcium ions
117
Describe the mechanism engaged by adrenaline binding to the beta-2 adrenergic receptor.
beta2 adrenergic receptor: GPCR
G-protein activates adenylate cyclase
Increases intracellular concentration of cAMP, made from ATP
increased cAMP activates cAMP-dependent protein kinase
118
What is the name of the cAMP degrading enzyme?
cAMP phosphodiesterase
119
What does CREB stand for? What is its function?
CREB: cAMP response element binding protein
transcription factor specific to cAMP, that binds togene sequences that have cAMP response elements (CRE) in their promoter, and activates transcription
120
Explain how the mechanisms of action of cholera and pertussis toxins differ although both lead to fluid loss from tissue.
CHOLERA TOXIN
cleavage of olgomeric complex of cholera toxin --> activated complex --> enters intestinal epithelial cells --> stimulate Gs in absence of GPCRs --> overstimulation of cAMP production --> release of water and ions into the lumen of the small intestine --> rapid fluid loss and dehydration
PERTUSSIS TOXIN
toxin enters lung epithelial cells --> inhibits Gi --> increases cAMP production --> release of water and ions into the lumen of the small intestine --> fluid loss
121
What kind of signal molecule activates receptor tyrosine kinases?
dimers
122
What cellular processes does the Ras protein superfamily (associated with kinase receptors) regulate?
- proliferation
- cytoskeletal dynamics
- membrane trafficking/ vesicular transport
123
In what disease family are Ras proteins mutated in approximately 20% of the cases?
human cancer
124
Which of the nicotinic or the muscarinic ACh receptors is metabotropic?
mAChR
125
What is the autonomic predominate tone of the heart?
parasympathetic
126
Give the 10 effects of anticholinesterases.
- salivation
- lacrimation
- urination
- defecation
- GI upset
- emesis
- bronchoconstriction
- bradycardia
- hypotension
- pupillary constriction
127
Name two agonists of mAChR, that do not affect nAChR.
bethanechol
| pilocarpine
128
Distinguish between mAChR M1, M2 and M3
M1
- found mostly in autonomic ganglia and glands
- increases production of IP3 and DAG
- increases secretions
M2
- found mostly in the atria of the heart
- decrease cAMP production
- cardiac inhibition
M3
- found mostly in exocrine glands, smooth muscle and endothelium
- increases production of IP3 and DAG
- increases gastric and salivary secretion, GI smooth muscle contraction, ocular accommodation and vasodilation
129
In which tissue can mAChR be found, although the organ is not supplied by the parasympathetic system? (besides sweat glands)
blood vessels
130
Name the respective clinical uses of pilocarpine and bethanechol.
PILOCARPINE
- to induce miosis
- to treat glaucoma
- to treat xerostomia (dry mouth)
BETHANECHOL
- to treat bladder and GI hypotonia
131
Name two mAChR antagonists with CNS effects, and 3 without.
WITH CNS EFFECTS
- atropine
- hyoscine hydrobromide
WITHOUT CNS EFFECTS
- glycopyrronium
- hyoscine butylbromide
- ipratropium
132
Why is there little therapeutic uses for mAChR agonists?
very few diseases of decreased parasympathetic activity
133
Define nystagmus.
side-to-side movements of the eyes when movement is in one direction is more rapid than in opposite direction
134
Give one other name for rotatory nystagmus. Which direction is the movement the fastest? What about post-rotatory nystagmus?
= optokinetic nystagmus
rotatory nystagmus: fast movement in direction of travel
post-rotatory nystagmus: fast movement in opposite direction of travel
135
Which set of semi-circular canals are being stimulated in post-rotatory nystagmus?
the horizontal set
136
How would you induce nystagmus in a patient?
caloric irrigation: water a few degrees warmer/cooler is put into the patient's ear
137
Which antibiotic can damage hair cells of semi-circular canals? What would be the consequence?
streptomyocin
when walking, cannot form a recognisable image (might not recognise friends)
