Blood Supply of Brain and Infarcts

Aphasia

Spinal Cord Lesions

Here are some mnemonics to remember spinal cord lesions. Hope they help!

Central Cord Lesion (syringomyelia)
First Lady Chiari went to Central Park with a cape and syringe.
First Lady Chiari-Chiari I
Central Park-Central Cord Syndrome
cape-cape-like distribution of loss of pain and temperature
syringe-syrinx

Anterior Horn Lesion (ALS)
Gehrig climbed a pyramid, blew on the ant hero's horn, and then looked up and down.
Gehrig-Lou Gehrig's (ALS)
ant hero's horn-anterior horn
pyramid-pyramidal tract
up and down-upper and lower motor neuron lesions

Posterior Column Syndrome
Lhermitte walked into the posterior column and lost his joint and reflex hammer. He got mad and started stomping.
Lhermitte-Lhermitte's sign
posterior column-posterior column syndrome
lost joint-loss of joint sensation
lost reflex hammer-areflexia
stomping-"stomping gait" because of loss of proprioception
(One type is Tabes Doralis which is seen after a syphilis infection, has a positive Romberg test, and Argyll Robertson pupil.)

Posterolateral Column Lesion (SCD)
If you don't have B12 and copper, or use too much NO, the posterolateral column will be too weak to balance. If you hold it in place all the time, your fingers will get tingly and pale.
don't have B12 or copper-B12 and copper
too much NO-exposure to nitric oxide
posterolateral column-posterolateral column lesion
too weak to balance-weakness and loss of balance
tingly-abnormal sensation like tingliness
pale-pernicious anemia

Causes of Hemicord Lesion
Ms. Varicella pressed down on half the cord and then pierced it halfway.
Ms.-MS or multiple sclerosis
Varicella-varicella zoster
pressed down on half the cord-asymmetric compression
pierced it halfway-penetrating trauma
mentioned half alot-hemicord lesion

Special thanks to Aditi!

Rotator Cuff

The four muscles that make up the rotator cuff are supraspinatus, infraspinatus, teres minor, and subscapularis. Subscapularis inserts on the lesser tubercle of the humerus while the other three muscles insert onto the greater tubercle.

It is believed that swimmer's shoulder is caused by the impingement of the tendon of the supraspinatus muscle as it passes through the subacromial space. This also makes the supraspinatus more suspectible to tear.

Thanks to Honglin!

Acetylcholine

Unlike dopamine, there is an increase in acetylcholine in Parkinson's disease. This neurotransmitter is synthesized in the basal nucleus of Meynert (basal forebrain). In the autonomic nervous system, it serves as the neurotransmitter for sweat glands and adrenal medulla. In the peripheral nervous system, acetylcholine plays a role in skeletal muscle activation, specifically between the motor nerve and skeletal muscle. In the central nervous system it is involved in alertness, attention, and learning. Acetylcholine receptors are classified as either nicotinic or muscarinic.

Other disorders involving acetylcholine include Myasthenia gravis and Alzheimer's disease.

1. Myasthenia gravis
In Myasthenia gravis, the body produces antibodies against acetylcholine nicotinic receptors, inhibiting proper acetylcholine signal transduction. As a result, the patient suffers from weakness and fatigue.

2. Alzheimer's disease
In Alzheimer's disease, plaques are formed in the brain. The plaque lead to cell death and decreased levels of the acetylcholine in the cerebral cortex and caudate nucleus. Treatment of Alzheimer's include acetylcholinesterase inhibitors, which prevent the breakdown of acetylcholine to make up for the lack of neurotransmitter.

Dopamine

Parkinson's Disease is a neurological disorder marked by tremors, stiffness and decreased movement. The main pathological characteristic is cell death in the substantia nigra (specficially the pars compacta), where dopamine is produced. Dopamine is a neurotransmitter that is responsible for movement and emotional responses. It also acts in regulating the rewards and pleasure centers of the brain. Therefore decrease in dopamine would result in less movement. A lack of dopamine also affects the basal ganglia, a group of nuclei at the base of the forebrain. The basal ganglia are involved in voluntary motor control, habit learning, eye movements, and cognitive and emotional functions.

Decreased levels of dopamine are also seen in depression, while increased levels are seen in schizophrenia (difficulty distinguishing reality from imagination) and Huntington Disease (chorea and dystonia).

Thiamine Deficiency

Thiamine (Vitamin B1), like all vitamin B molecules, are water soluble. So our bodies need to be constantly resupplied with Vitamin B. A deficiency can lead to health problems such as Beriberi and Korsakoff's syndrome.

1. Beriberi
Vitamin B1 acts as a coenzyme in carbohydrate metabolism and in pentose phosphate pathway. Without it, the body cannot properly extract energy from food. Pyruvic acid builds up and causes loss of mental awareness, difficulty breathing, and heart problems.

2. Korsakoff's Syndrome
Korsakoff's syndrome is more common among alcoholics. Like with Beriberi, the brain needs to be able to extract energy from carbohydrates. Without enough energy, the brain cannot properly function. This can lead to degeneration of mammillary bodies or disruptions in signal pathways. As a result, a patient may experience memory loss and confabulation.