09/03/2021 [muscles of the hand, muscles of the forearm, stomach physiology, Korsakoff syndrome, narcolepsy] Flashcards

Question

Attachment, actions and innervation of the flexor carpi ulnaris

Answer 1

Attachments: Originates from the medial epicondyle with the other superficial flexors. It also has a long origin from the ulna. It passes into the wrist and attaches to the pisiform carpal bone. Actions: Flexion and adduction at the wrist. Innervation: Ulnar nerve

Answer 2

Attachments: Originates from the medial epicondyle, attaches to the flexor retinaculum of the wrist. Actions: Flexion at the wrist. Innervation: Median nerve.

Answer 3

This muscle is absent in about 15% of the population. Dissection Tip: Just distal to the wrist, if you reflect back the palmaris longus, you will find the median nerve immediately underneath it

Answer 4

Attachments: Originates from the medial epicondyle, attaches to the base of metacarpals II and III. Actions: Flexion and abduction at the wrist. Innervation: Median nerve

Answer 5

The lateral border of the pronator teres forms the medial border of the cubital fossa, an anatomical triangle located over the elbow. Attachments: It has two origins, one from the medial epicondyle, and the other from the coronoid process of the ulna. It attaches laterally to the mid-shaft of the radius. Actions: Pronation of the forearm. Innervation: Median nerve

Answer 6

The flexor digitorum superficialis is the only muscle of the intermediate compartment. It can sometimes be classed as a superficial muscle, but in most individuals, it lies between the deep and superficial muscle layers.

Answer 7

The muscle is a good anatomical landmark in the forearm – the median nerve and ulnar artery pass between its two heads, and then travel posteriorly.

Answer 8

Attachments: It has two heads – one originates from the medial epicondyle of the humerus, the other from the radius. The muscle splits into four tendons at the wrist, which travel through the carpal tunnel, and attaches to the middle phalanges of the four fingers. Actions: Flexes the metacarpophalangeal joints and proximal interphalangeal joints at the 4 fingers, and flexes at the wrist. Innervation: Median nerve

Answer 9

Flexor digitorum profundus, flexor pollicis longus, pronator quadratus

Answer 10

Attachments: Originates from the ulna and associated interosseous membrane. At the wrist, it splits into four tendons, that pass through the carpal tunnel and attach to the distal phalanges of the four fingers. Actions: It is the only muscle that can flex the distal interphalangeal joints of the fingers. It also flexes at metacarpophalangeal joints and at the wrist. Innervation: The medial half (acts on the little and ring fingers) is innervated by the ulnar nerve. The lateral half (acts on the middle and index fingers) is innervated by the anterior interosseous branch of the median nerve.

Answer 11

This muscle lies laterally to the FDP. Attachments: Originates from the anterior surface of the radius and surrounding interosseous membrane. Attaches to the base of the distal phalanx of the thumb. Actions: Flexes the interphalangeal joint and metacarpophalangeal joint of the thumb. Innervation: Median nerve (anterior interosseous branch)

Answer 12

A square shaped muscle found deep to the tendons of the FDP and FPL. Attachments: Originates from the anterior surface of the ulna and attaches to the anterior surface of the radius. Actions: Pronates the forearm. Innervation: Median nerve (anterior interosseous branch).

Answer 13

Ulnar nerve

Answer 14

Parietal cells

Answer 15

Water and CO2 [in parietal cell] -> carbonic acid [H2CO3] + carbonic anhydrase -> H+ + HCO3- H+ then transported into the stomach lumen via H+ -K+ ATPase ion pump [using ATP and K+]. The bicarbonate ion is transported out of the cell into the blood via a transporter protein called anion exchanger which transports the bicarbonate ion out the cell in exchange for a chloride ion (Cl–). This chloride ion is then transported into the stomach lumen via a chloride channel. This results in both hydrogen and chloride ions being present within the stomach lumen. Their opposing charges leads to them associating with each other to form hydrochloric acid (HCl)

Answer 16

At rest, the number of H+– K+ ATPases present within the parietal cell membrane is minimal. The rest are sequestered within tubulovesicles in the parietal cell

Answer 17

Upon stimulation the vesicles fuse with the cell membrane which leads to the increased insertion of H+– K+ ATPase into the membrane, hence allowing for the increased movement of hydrogen ions into the stomach thus increasing acid production

Answer 18

Three ways: - via ACh which is released from the vagus nerve - via gastrin secretaed by G cells - via enterochromaffin like cells which secrete histamine

Answer 19

There are three ways in which acid production is increased. The first of these is via ACh, which is released from the vagus nerve. This is released firstly during the cephalic phase of digestion, which is activated upon seeing or chewing food, leading to direct stimulation of parietal cells via the vagus nerve. It is also produced during the gastric phase of digestion when intrinsic nerves detect distension of the stomach, stimulating the production of ACh by the vagus nerve

Answer 20

The main regulation pathway involves the hormone gastrin which is secreted from G cells in the stomach. G cells are activated by the vagus nerve, gastrin related peptide and by peptides in the stomach lumen produced via protein digestion. Activation of the G cells leads to the production of gastrin which is released into the blood and travels through the blood until it reaches the parietal cells. Gastrin binds to CCK receptors on the parietal cells which also elevates calcium levels causing increased vesicular fusion

Answer 21

Finally, enterochromaffin like cells in the stomach secrete histamine which binds to H2 receptors on the parietal cells. These cells release histamine in response to the presence of gastrin and ACh. This leads to increased fusion however it is via the secondary messenger cAMP as opposed to calcium in the other methods

Answer 22

There are a number of ways in which acid production can be decreased. The first of these is via accumulation of acid in the empty stomach between meals. This increase in acid leads to a lower pH within the stomach, which inhibits the secretion of gastrin, via the production of somatostatin from D cells. Once food has been broken down into chyme, it passes into the duodenum, triggering the enterogastric reflex. This reflex can be stimulated by distention of the small bowel, if there is excess acid in the upper intestine, the presence of protein breakdown products as well as excess irritation to the mucosa. Inhibitory signals are sent to the stomach via the enteric nervous system, as well as signals to medulla – reducing vagal stimulation of the stomach. The enterogastric reflex, is important is slowing down gastric emptying when the intestines are already filled. The presence of chyme within the duodenum also stimulates entero-endocrine cells to release cholecystokinin and secretin, both of which play a variety of important roles in completing digestion, but also inhibit gastric acid secretion. Secretin is released by the S cells of the duodenum when there is excessive acid production in the stomach. Other hormones including glucose dependent insulinotropic peptide (GIP) and vasoactive intestinal polypeptide also work to decrease acid production in the stomach

Answer 23

Peptic ulcers

Answer 24

Excessive bleeding due to erosion through a blood vessel

Answer 25

H2 antagonists such as ranitidinebind to the H2 receptors preventing the binding of histamine and thus reduce acid secretion. Proton pump inhibitors (PPIs) such as omeprazolebind to the H+– K+ ATPase (proton pump), hence preventing the transportation of hydrogen ions into the stomach lumen. PPIs completely prevent stomach acid formation due to hydrogen ions not being able to react with chloride ions in the stomach.

Answer 26

This is a state where there is a decrease in the volume of stomach acid produced. Achlorhydria can result in an increased risk of salmonella and cholera. There are a variety of causes and further tests must be undertaken to ascertain the cause to allow for a targeted treatment regime.

Answer 27

The appetite control centre is located in the hypothalamus. Within in hypothalamus lies the arcuate nucleus, which plays a key role in the control of appetite.

Answer 28

The appetite centre contains both primary and secondary neurones. The primary neurones process external signals, be it neuronal, hormonal or nutritional. The secondary neurones are then responsible for co-ordinating the inputs received via the primary neurone

Answer 29

Excitatory: Neuropeptide Y (NPY) and Agouti-related peptide (AgRP). These promote hunger. Inhibitory: POMC and CART. POMC can be cleaved into other neurotransmitters such as α-MSH and β-endorphin. These suppress hunger.

Answer 30

Ghrelin is a peptide hormone produced in the pancreas and released from the stomach wall when the stomach is empty. This stimulates the excitatory primary neurones, and therefore stimulates appetite. When the stomach is full, ghrelin release is inhibited, thus the appetite stimulus is also inhibited. PYY (full name – peptide tyrosine tyrosine) is a short peptide hormone released by cells in the ileum and colon in response to feeding. It inhibits the excitatory primary neurones of the arcuate nucleus. This causes appetite suppression

Answer 31

Leptin is a peptide hormone released into the blood by adipocytes (fat cells). Leptin stimulates the inhibitory neurones and inhibits the excitatory neurones in the arcuate nucleus to cause suppression of appetite. Insulin is a hormone released from beta cells in the islets of Langerhans of the pancreas. This suppresses appetite in a similar way to leptin

Answer 32

Leptin deficiency may arise from deletion of the leptin gene causing severe obesity, hyperphagia (excessive eating) and a reduced metabolic rate. However, this is incredibly rare. Leptin deficiency can also be found in conditions and syndromes where there is significant lipodystrophy. The effects of leptin deficiency can be reversed with the use of exogenous leptin

Answer 33

Gastric mucus is a gel-mucous barrier secreted by epithelial cells and glandular cells in the stomach wall.

Answer 34

It acts as part of a barrier that protects the stomach wall from the acid and digestive enzymes within the stomach lumen. This barrier is also made up of a bicarbonate secretion and the epithelial cells themselves, which are tightly joined together. Together, these components prevent the stomach from effectively digesting itself

Answer 35

Mucus is secreted by the stomach epithelial cells, but the mucus is mainly secreted from foveolar cells, found in the necks of the gastric pits. Mucus-secreting cells are the most abundant cell type in the stomach, giving indications of how important mucus is to the functioning stomach

Answer 36

The cells that make up the epithelial layer are not spread across the stomach wall equally. All across the stomach are deep gastric glands; pits made up by invaginations of stomach epithelial cells.

Answer 37

In the extreme zones of the stomach – the pyloric region and the cardia – these gastric glands only secrete mucus.

Answer 38

In the other regions however, there is greater cellular diversity in the constituents of the gastric glands: Parietal cells secrete hydrochloric acid and Intrinsic factor Chief cells secrete pepsinogens ECL cells secrete histamine

Answer 39

The production of mucus is conducted by stomach surface epithelial cells and foveolar cells. The mucus itself is around 95 per cent water, with the remaining five per cent made up of polymers that give the mucus its gel-like viscosity.

Answer 40

The viscosity of mucus is dynamic and can be altered by the rate of secretion from glandular cells or rate of breakdown by proteolytic enzymes within the stomach lumen

Answer 41

The bicarbonate element of the mucus is important as it allows an increased pH local to the epithelial cells, protecting them from the highly acidic stomach environment. These bicarbonate ions are formed in the mucus-secreting cells by reacting carbon dioxide with water, using the enzyme carbonic anhydrase. The bicarbonate ions are then pumped into the mucus layer by exchanging them with chloride ions

Answer 42

Much like the control of salivary secretions, the gastric secretions (including mucus secretion) is largely controlled by neural influences. An increase in mucus production is signalled by a stimulation of the Vagus nerve (Cranial nerve 10) and is mediated by prostaglandins. The cells respond to external factors such as mechanical stress and elements of the cephalic and gastric digestion phases by increasing mucus productions as required. In healthy patients, there is always a thick mucus layer to protect the stomach from auto-digestion

Answer 43

If for some reason the mucus layer is breached, the epithelial cells are exposed to concentrated stomach acid and the digestive enzymes contained within the gastric juices. As the stomach wall is made up of the same proteins and lipids as many foods we eat, if this mucosal barrier is broken the stomach will begin to digest itself, forming a peptic ulcer

Answer 44

There are certain precipitations to this condition, including gastric colonisation of Helicobacter pylori, exposure to nonsteroidal anti-inflammatory drugs (NSAIDs) such as ibuprofen, and excess acid secretion as seen in Zollinger-Ellison syndrome

Answer 45

The effect of NSAIDs on gastric mucus secretion has been known for around 40 years. Drugs such as ibuprofen and aspirin have revolutionised the immediate management of pain and inflammation, but can have adverse effects on the gastrointestinal mucosa. NSAIDs work by blocking the synthesis of prostaglandins, which play an important role in both pain sensation and mucosal maintenance. When prostaglandins are blocked, less gastric mucus is secreted, cellular junctions become less tight and mucosal blood flow is less adequately maintained. This makes the mucus layer less effective at protecting the stomach epithelium as well as less effective at managing any subsequent damage to the epithelium. This is why patients on chronic intakes of NSAIDs are at a much higher risk of peptic ulcers

Answer 46

Narcolepsy is a long-term neurological disorder that involves a decreased ability to regulate sleep-wake cycles.

Answer 47

Symptoms often include periods of excessive daytime sleepiness and brief involuntary sleep episodes.

Answer 48

About 70% of those affected also experience episodes of sudden loss of muscle strength, known as cataplexy.

Answer 49

These experiences can be brought on by strong emotions. Less commonly, there may be vivid hallucinations or an inability to move (sleep paralysis) while falling asleep or waking up.

Answer 50

People with narcolepsy tend to sleep about the same number of hours per day as people without, but the quality of sleep tends to be lessened.

Answer 51

The exact cause of narcolepsy is unknown, with potentially several causes.[3] In up to 10% of cases, there is a family history of the disorder. Often, those affected have low levels of the neuropeptide orexin, which may be due to an autoimmune disorder. In rare cases, narcolepsy can be caused by traumatic brain injury, tumors, or other diseases affecting the parts of the brain that regulate wakefulness or REM sleep.

Answer 52

Diagnosis is typically based on the symptoms and sleep studies, after ruling out other potential causes

Answer 53

Excessive daytime sleepiness can also be caused by other sleep disorders such as sleep apnea, major depressive disorder, anemia, heart failure, drinking alcohol and not getting enough sleep. Cataplexy may be mistaken for seizures

Answer 54

While there is no cure, a number of lifestyle changes and medications may help. Lifestyle changes include taking regular short naps and sleep hygiene. Medications used include modafinil, sodium oxybate and methylphenidate. While initially effective, tolerance to the benefits may develop over time

Answer 55

Tricyclic antidepressants and selective serotonin reuptake inhibitors (SSRIs) may improve cataplexy

Answer 56

Untreated narcolepsy increases the risk of motor vehicle collisions and falls

Answer 57

There are two main characteristics of narcolepsy: excessive daytime sleepiness and abnormal REM sleep

Answer 58

Narcoleptics may not be able to experience the amount of restorative deep sleep that healthy people experience due to abnormal REM regulation – they are not "over-sleeping". Narcoleptics typically have higher REM sleep density than non-narcoleptics, but also experience more REM sleep without atonia.[5] Many narcoleptics have sufficient REM sleep, but do not feel refreshed or alert throughout the day.[6] This can feel like living their entire lives in a constant state of sleep deprivation

Answer 59

The classic symptoms of the disorder, often referred to as the "tetrad of narcolepsy," are cataplexy, sleep paralysis, hypnagogic hallucinations, and excessive daytime sleepiness

Answer 60

Estimates of frequency range from 0.2 per 100,000 in Israel to 600 per 100,000 in Japan.[2] These differences may be due to how the studies were conducted or the populations themselves. Similar M:F.

Answer 61

Narcolepsy can occur in both men and women at any age, although typical symptom onset occurs in adolescence and young adulthood. There is about a ten-year delay in diagnosing narcolepsy in adults.[13] Cognitive, educational, occupational, and psychosocial problems associated with the excessive daytime sleepiness of narcolepsy have been documented. For these to occur in the crucial teen years when education, development of self-image, and development of occupational choice are taking place is especially devastating. While cognitive impairment does occur, it may only be a reflection of the excessive daytime somnolence

Answer 62

Korsakoff syndrome (KS)[1] is an amnestic disorder caused by thiamine (vitamin B1) deficiency typically associated with prolonged use of alcohol.[2] The syndrome and psychosis are named after Sergei Korsakoff, the Russian neuropsychiatrist who discovered it during the late 19th century.

Answer 63

This neurological disorder is caused by a lack of thiamine in the brain, and is also exacerbated by the neurotoxic effects of alcohol.

Answer 64

When Wernicke encephalopathy accompanies Korsakoff syndrome the combination is called Wernicke–Korsakoff syndrome; however, a recognized episode of Wernicke encephalopathy is not always obvious

Answer 65

anterograde amnesia, memory loss for events after the onset of the syndrome retrograde amnesia, memory loss extends back for some time before the onset of the syndrome amnesia of fixation, also known as fixation amnesia (loss of immediate memory, a person being unable to remember events of the past few minutes)[3][4][5] confabulation, that is, invented memories which are then taken as true, due to gaps in memory, with such gaps sometimes associated with blackouts minimal content in conversation lack of insight apathy – interest in things is quickly lost, and there is an indifference to change

Answer 66

Thiamine is essential for the decarboxylation of pyruvate, and deficiency during this metabolic process is thought to cause damage to the medial thalamus and mammillary bodies of the posterior hypothalamus, as well as generalized cerebral atrophy.[7] These brain regions are all parts of the limbic system, which is heavily involved in emotion and memory

Answer 67

KS involves neuronal loss, that is, damage to neurons; gliosis, which is a result of damage to supporting cells of the central nervous system, and hemorrhage or bleeding also occurs in mammillary bodies. Damage to the medial dorsal nucleus or anterior nuclei of the thalamus (limbic-specific nuclei) is also associated with this disorder. Cortical dysfunction may have arisen from thiamine deficiency, alcohol neurotoxicity, and/or structural damage in the diencephalon

Answer 68

KS causes deficits in declarative memory in most people,[10] but leaves implicit spatial, verbal, and procedural memory functioning intact

Answer 69

KS is primarily a clinical diagnosis; imaging and lab tests are not necessary

Answer 70

It was once assumed that anyone suffering from KS would eventually need full-time care. This is still often the case, but rehabilitation can help regain some, albeit often limited, level of independence.[21] Treatment involves the replacement or supplementation of thiamine by intravenous (IV) or intramuscular (IM) injection, together with proper nutrition and hydration. However, the amnesia and brain damage caused by the disease does not always respond to thiamine replacement therapy. In some cases, drug therapy is recommended. Treatment typically requires taking thiamine orally for 3 to 12 months, though only about 20 percent of cases are reversible. If treatment is successful, improvement will become apparent within two years, although recovery is slow and often incomplete

Answer 71

Rates varies between country, but it is estimated to affect around 12.5% of heavy drinkers

Answer 72

What is linear scleroderma Scleroderma is a rare autoimmune disease in which an overproduction of abnormal collagen causes normal tissues to be replaced with thick, dense scar tissue that can affect underlying bones and muscles if left untreated. There are two forms of scleroderma: localized scleroderma (primarily affects the skin, most common form found in children) and systemic sclerosis (a chronic, degenerative disease rarely seen in children).

Answer 73

Linear scleroderma is a progressive loss of subcutaneous fat with pigment changes in the skin. It is a type of localized scleroderma in which the area of skin affected appears in a band. It typically first appears in young children on one side of the body. It can affect the trunk, arms, legs, face or neck, or multiple parts of the body. Symptoms of localized scleroderma may include: Shiny, thickened patches of skin Discolored (lighter or darker) skin Joint tightness Scleroderma can result in cosmetic problems, scarring, growth abnormalities and limited motion if joints are affected. Symptoms may resemble other medical conditions, so always consult your child’s physician to confirm her diagnosis before pursuing treatment.

Answer 74

Diagnosis of linear scleroderma is usually based on the changes in the skin and internal organs. Because linear scleroderma is often associated with a positive antinuclear antibody, an antibody test may help distinguish the type of scleroderma present. In addition to a complete medical history and physical examination, your child may undergo additional diagnostic testing, including an echocardiogram, electrocardiogram (EKG or ECG) or X-ray. An EKG can detect abnormal heart rhythms which may be caused by changes in the heart muscle tissue due to scleroderma. X-rays may detect changes in bone and soft tissues, the gastrointestinal tract, and the lungs caused by scleroderma

Answer 75

Linear scleroderma is sometimes confused with Parry-Romberg syndrome because both conditions are characterized by the same progressive loss of subcutaneous fat. Like Parry-Romberg disease, the onset of linear scleroderma occurs is in childhood and may involve the facial region. Unlike Parry-Romberg disease, there is no optic nerve dysfunction, burnout phase and generally no muscle or bone atrophy. Medical professionals who are experienced in diagnosing and treating children with linear scleroderma and Parry-Romberg syndrome will be able to distinguish between the two and provide an accurate diagnosis

Answer 76

Treatment for scleroderma depends on your child’s overall health and the severity of the condition. Treatment may include: Medication — Your child’s medical team may recommend medications such as nonsteroidal, anti-inflammatory medications (NSAIDs) or corticosteroids to relieve pain; penicillamine to slow the thickening process and delay damage to internal organs; or immunosuppressive medications. Skin protection — Sunblock or protective padding can be used to protect the affected area. Physical therapy — Physical therapy and exercise can be used to maintain muscle strength. Surgery — Surgical treatment may involve fat transferred by injection or excision of isolated patches of abnormal tissue. In the fat transfer technique, fat is aspirated from elsewhere in the body, cleaned, and reinjected into the tissue under the skin to add volume, contour and shape. This is a minimally invasive procedure and usually can be done on an outpatient basis. If large areas of discolored, irregular skin are involved, the preferred treatment option may be direct excision of the abnormal tissue with closure of the adjacent normal skin. While this procedure may leave a scar, the scar is typically less noticeable than the existing deformity. This procedure is also typically done on an outpatient basis, and your child can return home the same day. In severe atrophy, large amounts of tissue may be transferred to the affected area using microsurgical techniques. This transferred tissue often comes from the trunk or legs. The tissue may be placed deeply to add volume, closer to the surface of the skin to replace damaged skin, or both

09/03/2021 [muscles of the hand, muscles of the forearm, stomach physiology, Korsakoff syndrome, narcolepsy] Flashcards

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