Spina Bifida Flashcards
In the sympathetic nervous system, what are the nerves and neurotransmitters involved?
Short preganglionic neuron, releases Ach Binds to nAchR on long postganglionic neuron Postganglionic releases NA, binds to adrenoreceptors
In the parasympathetic nervous system, what are the nerves and neurotransmitters involved?
Long preganglionic neuron, releases Ach Binds to nAchR on short postganglionic neuron Postganglionic neuron releases Ach, binds to mAchR
How many pairs of spinal nerves are there?
31
How many pairs of vertebrae are there in the spine?
33
What are the four regions of the spinal nerves?
Cervical Thoracic Lumbar Sacral & Coccygeal
How many cervical nerves are there?
8
How many thoracic nerves are there?
12
How many lumbar nerves are there?
5
How many sacral nerves are there?
5
How many coccygeal nerves are there?
1
Which are the parasympathetic spinal nerves?
Craniosacral Cranial nerves and S2-S4
Which are the sympathetic spinal nerves?
Thoracolumbar T1-L2
What is a myotome?
Group of muscles innervated by a single spinal nerve
What is a dermatome?
Area of skin innervated by a single spinal nerve
Which spinal nerve is special and why?
The C1 spinal nerve has no dermatome
How many pairs of cranial nerves are there?
12
Which number cranial nerve is the vagus nerve?
Cranial nerve X (10)
What are the general functions of the cranial nerves?
Smell, sight, eye movement, facial skin sensation, chewing, hearing, balance, taste, salivation, tongue movement, head turning, shoulder movement
What are the steps of excitation-contraction coupling in skeletal muscle? (up to calcium release)
Motor neuron releases Ach Ach binds to nAchR on the sarcolemma Sodium channels open, depolarising the sarcolemma Depolarisation propogates down t-tubules Depolarisation is detected by L-type VOCCs L-type VOCCs are mechanically linked to RyR on the SR Calcium released from SR
How is calcium stored in skeletal muscle cells?
Within the sarcoplasmic reticulum, bound to calsequestrin
What are the steps of skeletal muscle contraction?
Calcium binds to troponin C Causing tropomyosin to shift, exposing myosin binding sites on actin Myosin heads bind to actin and bend, releasing ADP+P and shortening the sarcomere ATP binds to the myosin head causing it to dissociate ATP hydrolysed to ADP+P to straighten the head
How is calcium removed from the cytoplasm of skeletal muscle cells?
SERCA channels on the SR
Draw out the structure of the sarcomere
Did you include M line, Z line, H zone, A zone and I zone in the right places?
What is the name of cranial nerve 3 and what does it control?
Oculomotor nerve Controls eye movement
What is the name of cranial nerve 7 and what does it control?
Facial nerve Facial sensation and movement
What is the name of cranial nerve 9 and what does it control?
Glossopharyngeal nerve Controls taste and salivation
Which receptors are coupled to Gs subunits?
All the beta-adrenoreceptors
Which receptors are coupled to Gi subunits?
a2, M2, M4
Which receptors are coupled to Gq subunits?
a1, M1, M3, M5
Which receptor is responsible for contraction of the bladder?
Mainly M3 - also M1 and M2
What receptor is responsible for internal sphincter contraction?
a1
What receptor is responsible for relaxation of the bladder detrusor muscle?
B3
Which 3 muscles control micturition and what must they do to allow micturition?
Bladder detrusor - contract Internal sphincter - relax External sphincter - relax
Is peeing sympathetic or parasympathetic?
Parasympathetic
Why might you need a drug to help relax the internal sphincter?
If there is a blockage, which may be caused by an enlarged prostate
What type of drug might be used to treat urinary incontinence?
Anticholinergics, such as M3 antagonists
What type of drug might be used to relax the internal sphincter?
a1 antagonists
What type of drug might be used to treat an overactive bladder?
B3 agonists
Which parasympathetic spinal nerves are responsible for control of micturition?
S2 and S3
Which part of the brain is involved in control of micturition?
Pons
What is an MEPP? What is it roughly?
Mini end plate potential, which is caused by the exocytosis of a single vesicle Roughly 0.4mV
How is Ach removed from the synaptic cleft?
Ach broken down into acetate and choline Choline is reuptaken by a sodium dependent co transporter on the presynaptic membrane
What is Myasthenia Gravis?
An autoimmune disease that damages the nAchR within the neuromuscular junction, leading to muscle weakness and fatigue
What is Duchenne Muscular Dystrophy?
An X-linked genetic degenerative disease that involves damage to the gene coding for dystrophin. Dystrophin links actin to the cell membrane in muscle fibres. Leads to muscle weakness and wasting
What are the key features of a good biomarker?
Easily obtainable through non-invasive methods Produced endogenously Sensitive & specific Provide quick results Have a cost-effective testing method Consistent across population Concentration correlates with disease progress
What type of molecules cannot pass the blood-brain barrier?
Hydrophilic/Polar molecules Blood cells Pathogens Large proteins
How could CSF analysis indicate a bacterial infection?
Increased presence of neutrophils
What does presence of lymphocytes in the CSF indicate?
Viral infection Myobacterial infection (TB) MS
What does high levels of protein in the CSF indicate?
Meningitus, MS, Syphilis, Brain/spinal cord tumour, Guillain-Barre syndrome
What does decresaed levels of glucose in the CSF indicate?
Presence of cells within the CSF that metabolise glucose such as bacterial cells, viral cells, white blood cells
What is unusual about sweat glands?
Although they are innervated by a sympathetic neuron, the long postganglionic sympathetic neuron releases Ach, whihc binds to muscarinic GPCRs to activate the gland (as opposed to NA and adrenergic receptors like all other symapthetic activity)
Which sympathetic spinal nerves are responsible for control of micturition?
L3
What are the 3 protective layers of the CNS?
(from inside to outside:) Pia mater Arachnoid Dura mater
Innervation of which organs leaves through the lateral horn?
Smooth muscle and cardiac muscle
In which week of development does the neural tube close?
Week 3-4
Name two supplements that are thought to reduce the occurrence of spinal cord defects
Folic Acid Inositol
What are the possible symptoms of spina bifida?
Hydrocephalus due to excess CSF accumulation in the head Problems with bladder/bowel control due to damaged spinal nerves
What are potential biomarkers of spina bifida?
Amniotic fluid can be tested for glial acidic fibrillary protein (GFAP) Also low red blood cell folate concentrations
Where is CSF produced and where is it located?
Produced by ependymal cells in the choroid plexus Resides in the ventricles and subarachnoid space
How is CSF circulated?
Pulsations of the choroid plexus and cilia
What type of neurons innervate myotomes?
Alpha neurons - innervate large, striated muscle Gamma neurons - innervated specialised muscle fibres and act as sensory neurons
How many myotomes and dermatomes are there?
31 of each
What is C-reactive protein?
An acute phase protein produced by the liver It is a non-specific biomarker of inflammation
What are the biomarkers of myocardial infarction?
Troponin I and troponin T Creatinine Kinase Myoglobin Natriuritic peptides
What are the advantages of myoglobin as a biomarker of myocardial infarction?
Detectable from 2 hours after injury High sensitivity but poor specificity
When are troponin I and troponin T detectable following myocardial infarction?
Detectable from 6 hours Peak at 24-48 hours Return to baseline after 5 days
What neurotransmitter is released by a motor neuron and what does it bind to?
Releases Ach at the neuromuscular junction Binds to nAchRs which allow sodium influx
