1st Semester Concepts Review

1st Semester Concepts Review

Jonathan AbesamisRoss University School of Medicine

August 15, 2010

Suboccipital Triangle

• Floor– Posterior Atlanto-occipital Membrane– Posterior Arch of Atlas

• Ceiling– Semispinalis Capitis

Attachments of Forearm Muscles (Deepest)

• Deepest Layer– Supinator - Lateral epicondyle of humerus, radial

collateral and anular ligaments, supinator fossa and crest of ulna.

– Pronator Quadratus - Distal fourth of anterior surface of ulna.

Attachments of Forearm Muscles (Deep)

• Deep Layer– Flexor Digitorum Profundus - Proximal 3/4 of

medial and anterior surfaces of the ulna and interosseous membrane.

– Flexor Pollicis Longus - Anterior surface of the radius and adjacent interosseous membrane.

Attachments of Forearm Muscles (Intermediate)

• Intermediate Layer– Flexor Digitorum Superficialis - Humeroulnar

head-medial epicondyle of humerus, ulnar collateral ligament, and coronoid process of the ulna, radial head-superior half of anterior border of radius.

Attachments of Forearm Muscles (Superficial)

• Superficial Layer– Pronator Teres Muscle - Medial epicondyle of

humerus and coronoid process of ulna.– Flexor Carpi Radialis - Medial epicondyle of the

humerus.– Palmaris Longus - Medial epicondyle of humerus.– Flexor Carpi Ulnaris - Humeral head-medial

epicondyle of humerus, ulnar head-olecranon and posterior border of ulna.

Innervation of Forearm Muscles

• All Median• Exceptions:– Supinator – Radial– Flexor Carpi Ulnaris - Ulnar

Endoplasmic Reticulum Detoxification

• Alcohol Increase in Smooth ER– Cytochrome p450– Detoxification of foreign substances.

Caspases

• Cysteine-aspartic Proteases• Necessary for apoptosis, necrosis, and

inflammation.• ↓Apoptosis = Tumor• ↑Apoptosis = Ischemia or Alzheimer’s Disease

Receptor-mediated Endocytosis

• Clatherin Assembles on Membrane• LDL Adaptin Clatherin

Centrosome

• Microtubule Organizing Center (MTOC)• 2 Perpendicular Centrioles

Definition of Incidence

• The rate or range of occurrence or influence of something, esp. of something unwanted: the high incidence of heart disease in men over 40.

Monosaccharide Classification

• Aldose Sugar = Primary Carbon• Ketose Sugar = Secondary Carbon• Contain one or more chiral centers—therefore

exist as two distinct enantiomers.• All biologically relevant monosaccharides are

in the D-configuration.• D-Glucose– C2, 4, 5 = Chiral

Peptide Bond

• A peptide bond (amide bond) is a covalent chemical bond formed between two molecules when the carboxyl group of one molecule reacts with the amine group of the other molecule, thereby releasing a molecule of water (H2O).

Conjugation in Prokaryotes

• Bacterial conjugation is the transfer of genetic material between bacterial cells by direct cell-to-cell contact or by a bridge-like connection between two cells.

• Bacterial conjugation is often incorrectly regarded as the bacterial equivalent of sexual reproduction or mating since it involves the exchange of genetic material.

• During conjugation the donor cell provides a conjugative or mobilizable genetic element that is most often a plasmid or transposon.

Herniated Disk

• Protrusion of the nucleus pulposus through the annulus fibrosus of the intervertebral disk into the intervertebral foramen or vertebral canal, compressing the spinal nerve root.

• Commonly occurs posterolaterally where the annulus fibrosus is not reinforced by the posterior longitudinal ligament.

• Frequently affects the lumbar region.

Sympathetic Trunk

• The sympathetic trunk travels in a downward direction from the skull, just lateral to the vertebral bodies. It interacts with the spinal nerves or their ventral rami by way of rami communicantes.

• The inferior part travels in front of the coccyx, where it converges with the other trunk at a structure known as the ganglion impar.

• Along the length of the sympathetic trunk are ganglia known as paravertebral ganglia.

Innervation of Breast

• Sensory innervation of the breast is dermatomal in nature. It is mainly derived from the anterolateral and anteromedial branches of thoracic intercostal nerves T3-T5.

Contraindication of MRI

• Electronically, magnetically, and mechanically activated implants: other pacemakers, e.g., – For the carotid sinus;– Insulin pumps and nerve stimulators; – Lead wires or similar wires

Repolarization of Action Potential

• In neuroscience, repolarization refers to the change in membrane potential that returns the membrane potential to a negative value after the depolarization phase of an action potential has just previously changed the membrane potential to a positive value.

• Repolarization results from the movement of positively charged potassium ions out of the cell.

Hypoventilation and Cervical Injury

• In medicine, hypoventilation (also known as respiratory depression) occurs when ventilation is inadequate.

• By definition it causes an increased concentration of carbon dioxide (hypercapnia) and respiratory acidosis.

• May be caused by spinal cord injury to cervical region.

VSD & FAS

• Fetal/Foetal alcohol syndrome (FAS) is a pattern of mental and physical defects which develops in some unborn babies when the mother drinks excessive alcohol during pregnancy.

• May cause Ventricular Septal Defect

Sequence of Eukaryotic Gene Expression

• Initiation– Promoter region of gene attracts RNA polyermase.– RNA polymerase combines with σ factor to create

RNA polymerase holoenzyme.• Elongation• Termination– Type I (Rho-independent) G-C rich area forms hairpin.– Type II (Rho-dependent) Rho factor proteins break H-

bonds between template DNA and RNA

Risk for Robertsonian Translocation

• Robertsonian translocation (ROB) is a common form of chromosomal rearrangement that in humans occurs in the five acrocentric chromosome pairs, namely 13, 14, 15, 21, and 22.

• Among life born, ~1/10 survive.

Down’s Syndrome

• 95% Trisomy 21 (47XX, +21 or 47XY, +21)• 4% Robertsonian (46XY,rob(14;21),+21 )• 1% Mosaicism• Mental Retardation• Specific shape of head, feet, and hands.• 40% Heart Malformations• Hyperthyroidism

Treatment of Androgen Insensitivity

• Androgen insensitivity syndrome (AIS), also referred to as androgen resistance syndrome, is a set of disorders of sex development caused by mutations of the gene encoding the androgen receptor.

• Treatment with cortisol, surgical reconstruction when needed.

Dx of Cockayne Syndrome

• Cockayne syndrome (also called Weber-Cockayne syndrome, or Neill-Dingwall Syndrome) is a rare autosomal recessive[1] congenital disorder characterized by growth failure, impaired development of the nervous system, abnormal sensitivity to sunlight (photosensitivity), and premature aging.

• Hearing loss and eye abnormalities (pigmentary retinopathy) are other common features, but problems with any or all of the internal organs are possible.

• It is associated with a group of disorders called leukodystrophies.

• The underlying disorder is a defect in a DNA repair mechanism.

Identify Frameshift Mutation

• Due to the triplet nature of gene expression by codons, the insertion or deletion can change the reading frame (the grouping of the codons), resulting in a completely different translation from the original.

Diphteria Toxin Interferes with Translocation

• It catalyzes the ADP-ribosylation of eukaryotic elongation factor-2 (eEF2), inactivating this protein. It does so by ADP-ribosylating the unusual amino acid diphthamide. In this way, it acts as a RNA translational inhibitor.

Functions of Golgi

• Organelle where proteins and lipids transferred from ER are modified and sorted.

• Site of synthesis of extracellular matrix GAGs• Clips N-Linked carbs from proteins and replaces with O-

linked sugars (Ser or Thr)• Location where glycolipids are formed.• Default path out of golgi is constitutive secretion.– Regulated Secretion (Insulin & Neurotransmitters)– Signal Mediated Diversion to Lysosomes (M6P on an N-linked

sugar)– Retention Signals (KDEL/BIP sequence)

DNA Polymerase

• Always polymerizes on a free 3’ OH using a deoxyribonucleoside triphosphate.

• Needs a RNA primer to initiate replication.

α Amanitin

• Inhibits RNA polymerase II in eukaryotic cells.

Puromycin

• Inhibits protein synthesis (translation) by virtue of its similarity to aminoacyl tRNA.

Review of Inheritance Patterns

• Every generation, gender equal = AD• Skips a generation, gender equal = AR• Less males, more females = X-linked Dominant• More males, less females = X-linked Recessive

Renal Disorder

• Proteins Found in Urine

Function of Integrins

• Integrins are receptors that mediate attachment between a cell and the tissues surrounding it, which may be other cells or the extracellular matrix (ECM). They also play a role in cell signaling and thereby define cellular shape, mobility, and regulate the cell cycle.

Prune Belly Syndrome

• Prune belly syndrome is a congenital disorder of the urinary system, characterized by a triad of symptoms.

• Complete lack of abdominal muscles. • There may be wrinkly folds of skin covering the abdomen.• Undescended testicles in males• Urinary tract abnormality such as unusually large ureters,

distended bladder, accumulation and backflow of urine from the bladder to the ureters and the kidneys

• Frequent urinary tract infections due to the inability to properly expel urine.

Causes of Scoliosis

• In some cases, scoliosis exists at birth due to a congenital vertebral anomaly.

• Most often the cause is unknown or idiopathic, having been inherited through multiple factors, including genetics.

• Scoliosis often presents itself, or worsens, during the adolescence growth spurt.

Development of the Skull

• Fontanels are the spaces between the cranial bones in infants.

• The bones are joined by membranes, which later ossify into bone.

• There are six fontanels: one anterior, one posterior, two sphenoid (or anterolateral) and two mastoid (or posterolateral).

• Most fuse by the first year, but the largest, the anterior fontanel, can be felt until age 2.

Derivatives of the Diencephalon

• Part of Forebrain• Thalamus• Hypothalamus• 3rd Ventricle

Compartment Syndrome of Anterior Compartment

• Innervation– Deep Peroneal

• Muscles Involved– Tibialis anterior– Extensor hallucis longus– Extensor digitorum longus

Excitation-Contraction Coupling

• Acetylcholine is released.• Action Potential is generated in the T tubules.• Voltage-sensing dihydropyridine receptors activated.• Transmitted to the voltage-mediated signal to

ryanodine receptors, resulting in a conformational change, opening the channel.

• Calcium ions released.• Troponin C on actin filaments.• Myosin forms a cross bridge.

Lactic Acidosis

• ↑Ethanol Consumption = Lactic Acidosis

Sickle Cell Heterozygotes

• The heterozygous form (sickle cell trait) is almost always asymptomatic, and the only usual significant manifestation is the renal concentrating defect presenting with isosthenuria.– Isosthenuria refers to the excretion of urine

whose specific gravity (concentration) is neither greater (more concentrated) nor less (more dilute) than that of protein-free plasma.

Sirenomelia

• Sirenomelia, alternatively known as Mermaid Syndrome, is a very rare congenital deformity in which the legs are fused together, giving them the appearance of a mermaid's tail.

Heart Axis Deviation

• RAD– RAD is common in taller individuals, as the apex of the

heart generally moves lower into the thorax.– This can also be seen in individuals with Situs Inversus

• LAD– Common causes include left ventricular hypertrophy,

left anterior fascicular block, inferior myocardial infarction, hypertension and emphysema.

Referred Pain in Thorax

• As a general rule, in the thorax and abdomen, general visceral afferent (GVA) pain fibers follow sympathetic fibers back to the same spinal cord segments that gave rise to the preganglionic sympathetic fibers.

Pneumothorax

• Pneumothorax (plural pneumothoraces) is a collection of air or gas in the pleural cavity of the chest between the lung and the chest wall. It may occur spontaneously in people without chronic lung conditions ("primary") as well as in those with lung disease ("secondary"), and many pneumothoraces occur after physical trauma to the chest, blast injury, or as a complication of medical treatment.

Pyruvate Dehydrogenase Deficiency

• It most commonly follows an X-linked inheritance pattern, but is approximately equally prevalent in both males and females.– This is because heterozygote females commonly

manifest severe symptoms.• It affects a gene which codes for a critical enzyme

complex, the Pyruvate dehydrogenase complex (PDC) which links the metabolic pathways of glycolysis and the citric acid cycle by transforming pyruvate into Acetyl CoA

Cytochrome c Oxidase

• The enzyme cytochrome c oxidase or Complex IV (PDB 2OCC, EC 1.9.3.1) is a large transmembrane protein complex found in bacteria and the mitochondrion.

• It is the last enzyme in the respiratory electron transport chain of mitochondria (or bacteria) located in the mitochondrial (or bacterial) membrane.

• It receives an electron from each of four cytochrome c molecules, and transfers them to one oxygen molecule, converting molecular oxygen to two molecules of water.

• Cyanide, sulfide, azide, and carbon monoxide[3] all bind to cytochrome c oxidase, thus competitively inhibiting the protein from functioning which results in chemical asphyxiation of cells.

Oligomycin

• Inhibition of ATP Synthase

Aortic Aneurysm

• An aortic aneurysm is a general term for any swelling (dilation or aneurysm) of the aorta, usually representing an underlying weakness in the wall of the aorta at that location. While the stretched vessel may occasionally cause discomfort, a greater concern is the risk of rupture, which causes severe pain; massive internal hemorrhage; and, without prompt treatment, results in a quick death.

Thoracic Duct

• In human anatomy, the thoracic duct (aka left lymphatic duct) is an important part of the lymphatic system—it is the largest lymphatic vessel in the body.

• It collects most of the lymph in the body (except that from the right arm and the right side of the chest, neck and head, and lower left lobe of the lung, which is collected by the right lymphatic duct) and drains into the systemic (blood) circulation at the left brachiocephalic vein, right between where the left subclavian vein and left internal jugular connect.

Myasthenia Gravis

• Autoimmune neuromuscular disease leading to fluctuating muscle weakness and fatiguability.

• Caused by circulating antibodies that block acetylcholine receptors at the post-synaptic neuromuscular junction, inhibiting the stimulative effect of the neurotransmitter acetylcholine.

• Treated medically with cholinesterase inhibitors or immunosuppressants, and, in selected cases, thymectomy.

• Ptosis, diplopia, and dysphagia.

Functioning of Dopamine Synapses

• DAT is an integral membrane protein that removes dopamine from the synaptic cleft and deposits it into surrounding cells, thus terminating the signal of the neurotransmitter. Dopamine underlies several aspects of cognition, including reward, and DAT facilitates regulation of that signal.

Ras in MAP Kinase Cascade

• When the GRB2-SOS complex docks to phosphorylated EGFR, SOS becomes activated.

• Activated SOS promotes the removal of GDP from a member of the Ras subfamily (most notably H-Ras or K-Ras).

• Ras can then bind GTP and become active.

References

• BRS Gross Anatomy 6th Edition• http://dictionary.com• http://wikipedia.com• http://download.videohelp.com/vitualis/med/

mmforarm.htm• http://emedicine.medscape.com/article/1273

133-overview• http://www.ehow.com/facts_5161986_skull-d

evelopment-infants.html