14. Nervous System II Workshop Flashcards
Describe the difference between the central nervous system and the peripheral nervous system.
The central nervous system includes the brain and spinal cord. The peripheral nervous system includes all nervous tissue in the body outside of the central nervous system.
Describe the role of the somatic nervous system
The somatic nervous system controls voluntary muscles and transmits sensory information to the central nervous system.
State TWO ways in which the following central nervous system components are protected:
a. Spinal cord
b. Brain
a. By the vertebral column and the meninges
b. By the cranium and the cranial meninges, CSF and the BBB
With regards to the layers of the meninges, compare functions of the:
a. Dura mater
b. Arachnoid mater
c. Pia mater
a. Dura mater is the tough outer layer that attach to the inside of the cranium and vertebral column for protection and support. It divides into two layers to create venous sinuses to drain blood out of the brain
b. Arachnoid mater is formed from collagen and elastic fibres helps to bridge the gap between the dura and pia mater.
c. Pia mater is a thin, transparent layer that contains blood vessels
Name the spaces between:
a. Dura mater and arachnoid mater
b. Arachnoid mater and pia mater
a. Subdural space
b. Subarachnoid space
Name the neuroglial cell that maintains the BBB.
Astrocytes
Name TWO arteries that supply the brain.
Vertebral and Carotid arteries
List FOUR major parts of the brain.
Cerebrum
Cerebellum
Diencephalon (Thalamus; hypothalamus; epithalamus)
Brainstem (medulla oblongata; pons; midbrain)
Name the area of the brain that contains the ‘pineal gland’.
Diencephalon/Epithalmus
List THREE factors that can damage the cerebellum.
- Chronic alcohol abuse
- Coeliac disease
- Thiamine (Vit B1) deficiency
List TWO functions of the cerebellum
- Maintenance of posture and balance
- Co-ordinate and smooth complex sequences of movement
- Correction of errors during ongoing movement
Name the area that connects the two cerebral hemispheres.
Corpus callosum
Name which cerebral lobe plays a role in:
a. Hearing
b. Vision
c. Motor skills
d. Sensory input
a. Temporal lobe
b. Occipital lobe
c. Frontal lobe
d. Parietal lobe
Which part of the brain may be damaged where symptoms of ‘ataxia’ are presenting?
The cerebellum
Describe how the left and right side of the brain co-ordinates the body.
The left side of the brain co-ordinates the right side of the body while the right side of the brain co-ordinates the left side of the body. This is because the corticospinal tracts cross over in the medulla oblongata.
Name THREE main structures within the limbic system.
Hypothalamus
Hippocampus
Amygdala
Name the area that plays a key role in emotions within the limbic system.
Amygdala
Name ONE cranial nerve which if damaged can lead to double vision.
Oculomotor (III)
Trochlear (IV)
Abducens (VI)
Name the largest cranial nerve of the autonomic nervous system.
Vagus nerve (X)
Name TWO cranial nerves that exhibit both sensory and motor functions.
Trigeminal nerve (V) Facial nerve (VII) Hypoglossal nerve (IX) Vagus nerve (X)
State where the spinal cord terminates.
At the vertebral level of L2 as the ‘conus’
Describe the difference between ‘motor tracts’ and ‘sensory tracts’ in white matter.
The motor tracts in spinal white matter are descending and the control voluntary and involuntary movement.
The sensory tracts are ascending and they transmit impulses from the skin, tendons, muscles and joints to the brain.
Describe the difference between ‘dorsal horns’ and ‘ventral horns’ in grey matter
The dorsal (posterior) horn receives sensory impulses whilst the ventral (anterior) horn sends out motor impulses
With regards to the spinal cord tracts, which is responsible for:
a. Pain and temperature
b. Voluntary movement
c. Light touch, vibration, proprioception
a. Spinothalamic tract
b. Corticospinal tract
c. Dorsal columns
Explain what could happen if there is damage to any of the spinal tracts
It would lead to loss of the tract’s function below that level of the body
Describe in detail the ‘reflex arc’
A reflex is a very fast, automatic, unplanned sequence of actions that occurs in response to a stimulus and includes:
- Sensory receptor
- Sensory neuron
- Interneuron
- Motor neuron
- Effector organ
State one key function of the thalamus
It is a major relay centre of sensory information to the cerebrum and integrates sensory and motor information
Name the three parts that make up the diencephalon
Thalamus
Epithalamus
Hypothalamus
List TWO causes of raised intracranial pressure (ICP)
Tumours (gliomas / metastases) Haemorrhage (subdural / subarachnoid) Hydrocephalus (excess CSF) Meningitis Encephalitis
List TWO aggravating factors for a headache associated with ICP
Coughing
Moving head
Worse on awakening
Explain what is meant by papilloedema in ICP
Bulging of the optical disc due to raised intracranial pressure
Describe the Cushing triad witnessed in ICP
Cushing’s triad are symptoms arising from the body’s attempt to lower ICP: elevated blood pressure; slow breathing; slow, irregular pulse
Describe the pathophysiology of hydrocephalus
The abnormal accumulation of CSF in the cerebral ventricles and subarachnoid space is usually due to impaired absorption but can be due to excessive secretion of the fluid.
It results in ventricular dilation and CSF permeating through the ependymal lining into the surrounding white matter.
List ONE cause of hydrocephalus in:
a. Small children
b. Older children / adults
a. Infection; congenital malformation
b. Trauma; tumours; meningitis
Explain why a headache associated with hydrocephalus is worse in the morning
From the build up of CSF that does not drain well whilst lying down
Explain why meningitis could be a medical emergency
Meningitis can be life-threatening when it leads to raised intracranial pressure.
Name TWO microorganisms that cause meningitis
Herpes simplex virus
Fungal or parasitic micro-organisms
Describe ONE skin sign in meningitis
Petechiae: small purple/red spots that are non-blanching
List TWO symptoms of meningitis
- Marked neck stiffness
- Fever and sudden severe headache
- Photophobia
- Vomiting
Name TWO signs of meningitis
- Kernig’s sign: pain resistance to knee extension when lying with hips fully flexed
- Brudzinski sign: neck flexion causes flexion of hip and knee
Using definitions, describe the difference between:
a. Concussion
b. Cerebral contusion
c. Coup and contrecoup
a. Concussion is a temporary loss of neuronal function resulting from a significant blow to the head
b. A traumatic brain injury that causes bruising of the brain with ruptured blood vessels and oedema
c. A common pattern of injury usually applied to cerebral contusions. Coup is the injury to the site of primary impact, while contrecoup is damage to the brain at a site contra-lateral to the site of trauma caused by the impact of the skull on the brain.
List FOUR causes of headaches
Dehydration Cervicogenic (from the neck) TMJ (structural problems) Tension headache Congested sinuses Hypoglycaemia Migraines / Cluster headaches Medication induced Intra-cranial: brain tumour, haemorrhage
Compare the location of a migraine to that of a tension headache
A migraine is usually retro-orbital and frontal, while a tension headache is diffuse (bilateral).
List TWO aggravating factors for a cervicogenic headache
Neck movement
Sustained posture
List TWO relieving factors for a cervicogenic headache
Stretching and supporting neck
Massage
Describe the difference in ‘headache duration’ with cervicogenic and migraine headaches
Migraine lasts from 4-72 hours while cervicogenic headace can last from one hour to weeks.
Name TWO dietary causes of migraine
Dairy
Caffeine
Gluten
Name ONE neurotransmitter deficiency in migraine
Serotonin
Explain what is meant by the ‘aura’
A period of unusual visual, olfactory and sensory experiences preceding a migraine
List TWO characteristic signs / symptoms of a brain tumour
- Morning headaches with increasing frequency
- Nausea and vomiting
- Uneven pupils and double vision
- Papilloedema
Name TWO headache red flags
- Thunderclap headache (subarachnoid haemorrhage)
- Accompanying signs of meningitis
- Signs of raised intracranial pressure (uneven pupils, double vision, papilloedema, vomiting without nausea
Define epilepsy
Sudden, hyper-excitable and uncontrolled neuronal activity in the brain
List TWO causes of epilepsy
- Idiopathic
- Brain tumours
- Cerebral infarction/haemorrhage
- Congenital malformation
- Head trauma
- CNS infections eg. meningitis
- Chemical imbalances eg. hypoglycaemia/calcaemia
List TWO trigger factors for epilepsy
Hypoglycaemia Fever Dehydration Stress Flickering lights Sleep deprivation Pesticides
Explain the difference between ‘tonic phase’ and ‘clonic phase’ of a tonic-clonic seizure
Tonic phase: contraction of all body muscles causing patient to fall if sitting/standing.
Clonic phase: rapid contraction and relaxation of muscles causing convulsions which can range from exaggerated twitches to violent shaking.
Describe how spina bifida develops
Spina bifida develops due to the incomplete closure of the embryonic neural tube resulting in failure of the spinal column to fully enclose the spinal cord
List ONE key nutrient deficiency that contributes to development of spina bifida
Folate (Vitamin B9)
Describe how a herniated disc develops
The nucleus pulposus of the disc leaks through the annulus fibrosus, often compressing on spinal nerves.
Describe the classic mechanism of injury with a herniated disc
Combined lumbar spine flexion and rotation
List TWO signs / symptoms of a herniated disc
- Radiating lower back pain (sharp and linear)
- Positive straight leg raise test (SLRT)
Describe ONE way in which the pain of a herniated disc is aggravated
Aggravated by coughing/sneezing
Name the longest and widest nerve in the body
The sciatic nerve
List TWO signs / symptoms of sciatica
- Pain in lower back and buttock
- Unilateral pain radiating down posterior leg into foot
- Pins and needles and numbness
- Weak calf muscles and ‘foot drop’
- Ankle jerk reflex often absent
Name TWO causes of sciatica
- Disc herniation at L4/5 or L5/S1
- Compression against piriformis muscle
- Tumours in the spinal canal or pelvis
Name ONE diagnostic test for sciatica
Straight leg raise test
Absent ankle jerk reflex
List ONE key side effect of aspartame
It is an excitotoxin* that is linked to MS and Parkinson’s
* Neurotoxin