One glucose molecule is converted into 2 pyruvate molecules, generating a net of 2 ATPs by substrate-level phosphorylation, and 2 NADHs. When oxygen is present, NADH delivers electrons to the electron transport chain in mitochondria to generate ATP by oxidative phosphorylation. Citrate synthase b. Aconitase c. Isocitrate dehydrogenase d. Succinyl-CoA thiokinase f. Succinate dehydrogenase g. Fumarase h. Biochemistry The citric acid cycle tricarboxylic acid cycle is a mitochondrial pathway that occurs only under aerobic conditions.
The citric acid cycle is NOT a means to convert acetyl groups to glucose. Humans lack the capacity to form glucose from acetyl-CoA. NADPH is important for fatty acid and steroid biosynthesis, maintenance of reduced glutathione to protect against reactive oxygen species ROS , and for bactericidal activity in polymorphonuclear leukocytes PMNs. RiboseP is required for nucleotide synthesis. Biochemistry Glycogen is a branched polymer of glucose, stored primarily in liver and skeletal muscles, which can be mobilized during hypoglycemia liver or muscular contraction muscles.
Synthesis of glycogen glycogenesis is mediated by glycogen synthase, while its breakdown glycogenolysis is carried out by glycogen phosphorylase. This is reversed by a debranching enzyme. Occurring only in liver, kidney, and intestinal epithelium, this pathway functions to provide glucose for the body, especially the brain and RBCs, which require glucose for energy the brain can also use ketone bodies during fasting conditions.
Gluconeogenesis occurs during fasting, as glycogen stores become depleted. Important substrates for gluconeogenesis are gluconeogenic amino acids protein from muscle , lactate from RBCs and muscle during anaerobic exercise , and glycerolP from triacylglycerol from adipose tissues. Instead, it is transported as malate in exchange for asparate via the malate shuttle. Biochemistry Amino acids are required for protein synthesis. Although some amino acids can be synthesized de novo nonessential , others essential must be obtained from the digestion of dietary proteins.
Nonessential amino acids are synthesized from intermediates of glycolysis and the citric acid cycle or from other amino acids. Classic homocystinuria, caused by a deficiency in cystathionine synthase, is associated with dislocated lens, deep venous thrombosis, stroke, atherosclerosis, mental retardation, and Marfan-like features. Deficiency of pyridoxine, folate, or vitamin B12 can produce a mild homocystinemia with elevated risk of atherosclerosis previously listed symptoms absent.
Methionine synthase homocysteine methyltransferase deficiency is extremely rare and is associated with megaloblastic anemia and mental retardation. Both of these are used for synthesis of urea in the liver for excretion via the urea cycle. Fatty acid synthesis occurs in the cytosol and involves the transport of acetyl-CoA from the mitochondria via the citrate shuttle, carboxylation to malonyl CoA, and linking together 2 carbons per cycle to form long fatty acid chains.
Triacylglycerols triglycerides , the storage form of fatty acids, are formed primarily in the liver and adipose tissues by attaching 3 fatty acids to a glycerolP. Triacylglycerols are transported from liver to adipose as VLDL. Fatty acids from the diet are transported as chylomicrons. Both are digested by lipoprotein lipase induced by insulin in the capillaries of adipose and muscle. Fatty acids may be mobilized from triacylglycerols in adipose by hormone-sensitive lipase.
Free fatty acids are delivered to tissues for beta oxidation. Diabetic ketoacidosis results from overactive hormone-sensitive lipase often in the context of stress, trauma, or infection.
Characterized by polyuria, dehydration, CNS depression and coma, sweet fruity breath acetone. Measure 3-hydroxybutyrate to more accurately evaluate ketoacidosis. Synthesis occurs primarily in the liver for storage and bile acid synthesis, but also in adrenal cortex, ovaries, and testes for steroid hormone synthesis. Cholesterol may also be esterified into cholesterol esters by acyl-cholesterol acyl-transferase ACAT in cells for storage.
Biochemistry Free fatty acids are transported by serum albumin, whereas neutral lipids triacylglycerols and cholesterol esters are transported by lipoproteins. Anti-CD3 increasing intensity of fluorescence Double stained The results of flow cytometry are often shown for question analysis.
Be sure to know the key CD markers and the biologic functions of the cells that possess them. They are the agents of kuru, mad cow disease, etc. Make sure you know those organisms that can confound a simple Gram-stain type of diagnosis, e. Nose Staphylococcus aureus S. It is encoded on the chromosome. LPS is heat stable and not strongly immunogenic, so it cannot be converted to a toxoid. IL-1 is a major mediator of fever. Damage to the endothelium from bradykinin-induced vasodilation leads to shock.
Coagulation DIC is mediated through the activation of Hageman factor. NO production causes hypotension, which contributes to shock. Exotoxin Exotoxins are protein toxins, generally quite toxic, and secreted by bacterial cells. They are encoded on plasmids or in lysogenic phage genomes. Transformation The uptake and incorporation of free DNA from the environment by competent cells followed by homologous recombination. Transposon A mobile genetic element capable of movement within a cell.
Formation of initiation complex Aminoglycosides 30S Linezolid 50S Interfere with initiation codon functions—block association of 50S ribosomal subunit with mRNAS bacteriostatic ; misreading of code—incorporation of wrong amino acid bactericidal 2. Formation of peptide bond Chloramphenicol 50S Inhibit the activity of peptidyltransferase bacteriostatic 4. Intracellular organisms both obligate and facultative are protected from antibody and complement.
Paroxysms chills, fever spike, and malarial rigors occur when the infected RBCs are lysed, liberating a new crop of merozoites. Relapse is an exacerbation from liver stages hypnozoites. Suppressive to avoid infection 2. Therapeutic eliminate erythrocytic 3. Radical cure eliminate exoerythrocytic 4. Gametocidal destruction of gametocytes Successful treatment is accomplished with chloroquine followed by primaquine.
Chloroquine therapy is suppressive, therapeutic, and gametocidal, whereas primaquine eliminates the exoerythrocytic form. Chloroquine-Sensitive Malaria P. Leishmania spp. Sandfly bite Amastigotes in macrophages in cutaneous lesions Leishmania braziliensis complex Mucocutaneous leishmaniasis Sandfly bite Same Definition of abbreviations: CSF, cerebrospinal fluid.
In babies, acute infections are often serious and involve the CNS. In older children and adults, mild acute infections may become chronic with the risk of development of cardiomyopathy and heart failure. Central, California, and N. Note: Viruses are listed from top to bottom in order of increasing size. If you know them in this order, then you can remember that the smallest 4 are naked wearing more clothing makes you larger.
Microbiology As viruses rely on host machinery to produce viral products, selectivity must be achieved by targeting minute differences in viral enzymes. They induce the synthesis of a number of antiviral proteins e. Morphologic and geographic clues are very important in determining the identity of the organism.
Consequently, treating fungal infections poses a clinical challenge, especially in immunocompromised patients. Fungal cell membranes contain ergosterol, a sterol not found in mammalian tissue. Thus, this difference provides the basis for most systemically administered antifungal agents. At fertilization, the secondary oocyte rapidly completes meiosis II. Cle Day 2 2-cell Blastula Day 3 4-cell Blastula Embryoblast Embryo Day 4 Trophoblast Placenta Morula Day 5 46, 2N Zygote Blastocyst Day 1 Day 6 Implantation begins Fertilization Ovary Zona pellcida Corona radiata cells Secondary oocyte arrested in metaphase of meiosis II Cytotrophoblast Ampulla of oviduct Blastocyst cavity Embryoblast Syncytiotrophoblast During the first 4 to 5 days of the first week, the zygote undergoes rapid mitotic division cleavage in the oviduct to form a blastula, consisting of increasingly smaller blastomeres.
This becomes the morula cell stage. A blastocyst forms as fluid develops in the morula. The blastocyst consists of an inner cell mass known as the embryoblast, and the outer cell mass known as the trophoblast becomes the placenta. At the end of the first week, the trophoblast differentiates into the cytotrophoblast and syncytiotrophoblast and then implantation begins.
Implantation usually occurs in the posterior superior wall of the uterus. Figure II Week 1 Clinical Correlation: Ectopic Pregnancy Tubal The most common form of ectopic pregnancy Usually occurs when the blastocyst implants within the ampulla of the uterine tube because of delayed transport Risk factors: endometriosis, pelvic inflammatory disease PID , tubular pelvic surgery, or exposure to diethylstilbestrol DES Clinical signs: abnormal or brisk uterine bleeding, sudden onset of abdominal pain that may be confused with appendicitis, missed menstrual period e.
Week 2 Epiblast Bilaminar disk Lacuna spaces The embryoblast differentiates into the epiblast and hypoblast, forming a bilaminar embryonic disk. The epiblast forms the amniotic cavity, and hypoblast cells migrate from the primary yolk sac. Extraembryonic mesoderm is derived from the epiblast.
Extraembryonic somatic mesoderm lines the cytotrophoblast, forms the connecting stalk, and covers the amnion. Extraembryonic visceral mesoderm covers the yolk sac. Embryology Hypoblast The connecting stalk suspends the conceptus within the chorionic cavity. The wall of the chorionic cavity is called the chorion, consisting of extraembryonic somatic mesoderm, the cytotrophoblast, and the syncytiotrophoblast.
Week 2 Human chorionic gonadotropin hCG is a glycoprotein produced by the syncytiotrophoblast. It stimulates progesterone production by the corpus luteum.
Low hCG levels may predict a spontaneous abortion or ectopic pregnancy. High hCG levels may predict a multiple pregnancy, hydatidiform mole, or gestational trophoblastic disease. By the end of this period, the embryo begins to look human.
Week 3 Clinical Correlation Sacrococcygeal teratoma: a tumor that arises from remnants of the primitive streak; often contains various types of tissue bone, nerve, hair, etc. Chordoma: a tumor that arises from remnants of the notochord, found either intracranially or in the sacral region Caudal dysplasia sirenomelia : a constellation of syndromes ranging from minor lesions of the lower vertebrae to complete fusion of lower limbs.
Occurs as a result of abnormal gastrulation, in which migration of mesoderm is disturbed. In a partial mole, there is a haploid set of maternal chromosomes and usually two sets of paternal chromosomes so that the typical karyotype is 69,XXY. Embryology The placenta permits exchange of nutrients and waste products between maternal and fetal circulations. If the twinning occurs very early on before the chorion forms , two separate chorions will form dichorionic.
All other possible types of twins are monochorionic because the chorion has already formed. Fraternal twins are dizygotic and identical twins are monozygotic. Multiple abnormalities, e. Diffusion Kinetics. Fluid Volume Compartments and Distribution. Membrane Potentials. Action Potential. Steady state Steady state is a condition in which a variable is maintained within narrow limits by regulating an opposing activity. This process requires energy. Negative feedback This is a common system that acts to oppose changes in the internal environment.
Negative feedback systems promote stability and act to restore steady-state function after a perturbation. Positive feedback This is a less common system also called a vicious cycle that acts to magnify a change in the internal environment; the initial change in a system is increased as a result of feedback activity. In a viable organism, any positive feedback system is ultimately overridden by one or more negative feedback systems. Negative Feedback Example Positive Feedback Example Follicular Phase Pre-ovulatory Phase Gonadotropin-releasing hormone Gonadotropin-releasing hormone Luteinizing hormone Luteinizing hormone Estradiol Estradiol The figures above show the negative feedback relationship between estrogens and the gonadotropins that dominates during the follicular phase, which transforms into a positive feedback relationship, producing the LH surge prior to ovulation.
Solid arrows show direct relationships stimulation and dashed arrows show inverse relationships inhibition. Active transport can produce a concentration gradient, and passive processes will lead to an equilibrium state right. Intracellular volume changes only when extracellular osmolarity changes. All substances enter or leave the body by passing through the extracellular compartment. Definition of abbreviation: RISA, radio-iodinated serum albumin.
The Darrow-Yannet diagram right represents this information. The y-axis is solute concentration or osmolarity. The solid line represents the control state, and the dashed line represents changes in volume or osmolarity. Proteins anions in cells that do not diffuse help establish the electrical potential across the membrane. The greater the conductance, the closer the membrane will approach the equilibrium potential of that ion.
Hyperpolarization occurs when the membrane potential becomes more negative. Depolarization occurs when the membrane potential becomes less negative or even positive. Definition of abbreviation: EC, extracellular. Physiology Absolute refractory period Relative refractory period Sodium equilibrium potential 60 mV Action potential 0 mV Sodium conductance Potassium conductance — 70 mV Resting equilibrium potential — 90 mV Potassium equilibrium potential Time The action potentials AP of excitable cells involve the opening and closing of voltage-gated channels for sodium, potassium, and in some cells, calcium.
The figure above shows a neuronal AP. The opening of a channel increases conductance. Steps are shown below. These channels can be blocked by tetrodotoxin. Clinical Correlations Calcium has a low resting conductance and does not contribute to the resting potential.
It has a very positive equilibrium potential, so when conductance increases e. Calcium concentration affects the action potentials and force of contraction of cardiac and smooth muscle. Hypercalcemia stabilizes excitable membranes, leading to flaccid paralysis of skeletal muscle. Hypocalcemia destabilizes membranes, leading to spontaneous action potentials and spasms.
Abnormal increases and decreases of extracellular potassium have severe consequences for cardiac conduction and rhythm. Renal and gastrointestinal disorders are likely to cause abnormalities of electrolytes and alteration of resting potentials and action potentials. As the Degree of Cellular Injury Worsens Irreversible Injury and Cell Death. Wound Healing. Connective Tissue Components. Connective Tissue Diseases.
The cellular response to injury depends on the type, duration, and severity of injury, the type of cell injured, metabolic state, and ability to adapt. Cells shrink; lipofuscin granules can be seen microscopically. May coexist with hyperplasia. Pathology Wound healing involves regeneration of cells in a damaged tissue, along with repair of the connective tissue matrix. Different types of collagen are found in different body sites. Thus, an early symptom is bleeding gums.
There are many types. Amyloidosis An accumulation of various insoluble fibrillar in various tissues. It stains with Congo red and shows apple-green birefringence with polarized light.
Pathology Carcinogenesis is a multistep process involving multiple genetic changes from inherited germ-line mutations or acquired mutations, leading to monoclonal expansion of a mutated cell. Pathology There are many proposed mechanisms of carcinogenesis. The most important mutations involve growth-promoting genes proto-oncogenes , growth-inhibiting tumor suppressor genes, and genes regulating apoptosis.
Clinically Important Oncogenes Proto-oncogenes are normal cellular genes involved with growth and cellular differentiation. Pathology Tumor suppressor genes encode proteins that regulate and suppress cell proliferation by inhibiting progression through the cell cycle. Pathology These are usually normal cellular components that are increased in neoplasms but may also be elevated in non-neoplastic conditions. Can be used for screening, monitoring of treatment efficacy, and detecting recurrence.
Low stage means a localized tumor. Stage rises as tumors spread locally then metastasize. It represents the ratio of drug elimination to its plasma concentration. For a drug with first-order elimination, clearance is constant. Rate of drug elimination Plasma drug concentration Elimination is synonymous with termination of drug action. The two primary mechanisms are hepatic metabolism to inactive metabolites or renal excretion. First-Order Elimination A constant fraction of drug is eliminated with time.
Units of Drug Most drugs have first-order elimination. It is constant for drugs eliminated by firstorder kinetics. Half-life is not applicable. For some drugs, their rapid hepatic metabolism decreases bioavailability. This can be avoided by giving the drug by an alternate route e. It is equal to the rate of elimination.
F If therapeutic plasma concentrations are needed quickly and the Vd is large, a loading dose may be given to produce the desired drug levels fill up the Vd without the typical delay of 4 to 5 half-lives.
There are two main types of metabolic reactions: phase I and phase II. Phase I The parent drug becomes more water-soluble by oxidation, reduction, or hydrolysis by cytochrome P isozymes also called mixed function oxidases located in smooth endoplasmic reticulum in liver, and in the GI, lungs, and kidney to a lesser extent. Often the drug is converted to compounds with little or no pharmacologic activity; in other instances, the metabolites retain pharmacologic activity.
Examples include glucuronidation, acetylation, sulfation, glutathione conjugation, and methylation. Phase II reactions lead to inactive molecules, which are polar and usually renally excreted. All phase II reactions use enzymes called transferases. It will elicit a partial response when administered alone. When administered with a full agonist, it acts as an antagonist because it displaces the full agonist from the receptor. It can be overcome by increasing the agonist dose.
A noncompetitive antagonist binds to the receptor without activating the effector system. It cannot be overcome by increasing the agonist dose. Log Dose of Drug Kd Potency: the measure of how much drug is required to produce a given effect. Efficacy: the maximal effect a drug can produce. It is also known as maximal efficacy. A partial agonist has a lower efficacy than a full agonist.
It can be less potent C or more potent A than a full agonist B. See figure to left. Figure I It is the percent of population responding versus log dose. Intracellular receptors Lipid-soluble agents diffuse across the plasma membrane to bind intracellular receptors e.
This permits receptor binding to nuclear DNA sequences that modify gene expression. Ligand binding causes dimerization and activates the enzyme activity often a tyrosine kinase. Examples: insulin and growth factor receptors. Transmembrane receptors that activate a separate tyrosine kinase These also form dimers when activated, then activate a separate cytoplasmic tyrosine kinase Janus kinases; JAKs.
The kinase phosphorylates STAT factors signal transducers and activators of transcription. STAT dimers then regulate transcription. Examples: cytokine and growth hormone receptors.
The autacoids include histamine, serotonin, vasoactive peptides, and prostaglandins see page Although the mechanism of action varies, each agent hinders cell replication in some way. Specificity relies on differential effect between neoplastic cells and normal tissue. The mechanism of action may be cell-cycle specific affecting cells in all stages except G0 or cell-cycle nonspecific. Inhibit synthesis of nucleic acids and thus protein synthesis. This class of agents causes alkylation of DNA, leading to cross-linking, abnormal base pairing, or DNA strand breakage.
Mechanisms of action vary. Doxorubicin Intercalates DNA, creating breaks. Hinders DNA replication and transcription. Prevents estrogen from binding estrogen receptor— positive breast CA cells, leading to involution of estrogen-dependent tumors. Cell-cycle specific drugs.
Most prevent the assembly of microtubules and the formation of the mitotic spindle. However, many of your patients may be taking herbal medicines such as these, and familiarity with these agents is useful. Anatomy of the Eye and Glaucoma. Pharmacology of the Eye. Drugs Used to Treat Glaucoma. Pupillary Light Reflex Pathway. Descending Pathways. Commonly Tested Muscle Stretch Reflexes. Ascending Pathways. Dorsal Column-Medial Lemniscus. Anterolateral Spinothalamic.
Classic Spinal Cord Lesions. Accommodation-Convergence Reaction. Clinical Correlations. Eye Movement Control Systems. Alzheimer Disease. Creutzfeldt-Jakob Disease. Pick Disease Lobar Atrophy. CNS Trauma. Cerebral Herniations. Neuromuscular junction Note: Arrows indicate lesion sites that result in Horner syndrome. Submandibular VI ganglion Submandibular gland Sublingual gland 3. Otic ganglion C1 Terminal ganglia Viscera of the thorax and abdomen foregut and midgut XI Descending hypothalamic fibers drive all preganglionic sympathetic neurons Internal carotid a.
External carotid a. Blood vessels are solely innervated by SANS nerve fibers. The uptake of choline into the nerve terminal is the ratelimiting step of ACh synthesis and can be blocked by hemicholinium. Note: The numbers in the figure correspond to the numbers in the table below. Mechanism of Action Agent Clinical Uses Other Notes and Toxicity Muscarinic antagonists Atropine Counteracts cholinergic toxicity Antidiarrheal Mydriatic agent for eye exams Reversal of sinus bradycardia and heart block Mydriasis and cycloplegia blind as a bat Decreased secretions dry as a bone Vasodilation red as a beet Delirium and hallucinations mad as a hatter Hyperthermia Tachycardia Urinary retention and constipation Sedation, amnesia Homatropine Cyclopentolate Tropicamide Ophthalmology topical , for mydriasis — Ipratropium Asthma and COPD Localized effect because is a quaternary amine; few antimuscarinic side effects Scopolamine Motion-sickness Antiemetic See side effects for atropine.
The effect of the blockade will be the opposite of what the predominant tone causes. In general, the predominant tone to blood vessels and sweat glands is sympathetic, and most everything else is parasympathetic. The first step of the synthetic pathway is carried out by tyrosine hydroxylase; it is also the rate-limiting step.
NE levels inside the presynaptic terminal may also be regulated by metabolism by monoamine oxidase MAO. Once released, NE binds to various adrenergic receptors to transmit its signal. Reuptake especially uptake-1 and diffusion are most important in the termination of action of NE and DA. Metabolites such as metanephrine, normetanephrine, vanillylmandelic acid VMA can be measured in the urine and are used in the diagnosis of diseases such as pheochromocytoma.
Note: The numbers in the figure correspond to the numbers in the following table. Meningeal spaces are spaces or potential spaces adjacent to the meninges. There are two main classes: amides and esters. Side Effects 1. The Nervous System General Anesthetics The ideal general anesthetic produces unconsciousness, analgesia, skeletal muscle relaxation, loss of reflexes, and amnesia.
There are two broad classes of general anesthetics: inhalational and intravenous. Treat with dantrolene. The primitive heart tube undergoes dextral looping bends to the right and forms five dilatations. Four of the five dilatations become subdivided by a septum.
Most of the common congenital cardiac anomalies result from defects in the formation of these septa. This results in an opening between the right and left atria. If the ASD is small, clinical symptoms may be delayed as late as age This is the most clinically significant ASD. The foramen ovale FO is the fetal communication between the right and left atria.
Premature closure of the FO is the closure of the FO during prenatal life. This results in hypertrophy of the right side of the heart and underdevelopment of the left side.
Patients with left-to-right shunting complain of excessive fatigue upon exertion. Left-to-right shunting of blood is not cyanotic but causes increased blood flow and pressure to the lungs pulmonary hypertension. Pulmonary hypertension causes marked proliferation of the tunica intima and media of pulmonary muscular arteries and arterioles.
At this stage, the condition is called Eisenmenger complex. VSD is the most common congenital cardiac anomaly. Figure legend: a, right bulbar ridge; b, left bulbar ridge; c, AV cushions.
The AP septum divides the truncus arteriosus into the aorta dark gray and pulmonary trunk light gray. Transposition of the Great Vessels Occurs when the AP septum fails to develop in a spiral fashion and results in the aorta opening into the right ventricle and the pulmonary trunk opening into the left ventricle. This causes right-to-left shunting of blood with resultant cyanosis.
Infants born alive with this defect must have other defects like a PDA or VSD that allow mixing of oxygenated and deoxygenated blood. Tetralogy of Fallot Occurs when the AP septum fails to align properly and results in 1 pulmonary stenosis, 2 overriding aorta, 3 interventricular septal defect, and 4 right ventricular hypertrophy. Tetralogy of Fallot is the most common congenital cyanotic cardiac anomaly. This results in a condition in which only one large vessel leaves the heart and receives blood from both the right and left ventricles.
This defect is always accompanied by membranous ventricular septal defect. Definition of abbreviation: PDA, patent ductus arteriosus. Patent ductus arteriosus PDA occurs when the ductus arteriosus connection between the pulmonary trunk and aorta fails to close after birth.
PDA is common in premature infants and cases of maternal rubella infection. It causes a leftto-right shunting of blood. Note: During fetal development, the ductus arteriosus is a right-toleft shunt.
Right and left umbilical arteries In the fetal circulation, the ductus venosus allows fetal blood to bypass the liver, and the foramen ovale and the ductus arteriosus allow fetal blood to bypass the lungs. Note the sites where the oxygen saturation level of fetal blood is the highest umbilical vein and the lowest ductus arteriosus.
The superior mediastinum contains the thymic remnants, superior vena cava and its brachiocephalic tributaries, aortic arch and its branches, trachea, esophagus, thoracic duct, and the vagus and phrenic nerves. The anterior mediastinum is anterior to the heart and contains remnants of the thymus. The middle mediastinum contains the heart and great vessels, and the posterior mediastinum contains the thoracic aorta, esophagus, thoracic duct, azygos veins, and the vagus nerves.
The inferior vena cava passes through the diaphragm at the caval hiatus at the level of the eighth thoracic vertebra; the esophagus through the esophageal hiatus at the tenth thoracic vertebra; and the aorta courses through the aortic hiatus at the level of the twelfth thoracic vertebra.
The right coronary artery supplies the right atrium, the right ventricle, the sinoatrial and atrioventricular nodes, and parts of the left atrium and left ventricle. The left coronary artery supplies most of the left ventricle, the left atrium, and the anterior part of the interventricular septum. The two main branches of the left coronary artery are the anterior interventricular artery LAD and the circumflex artery. The auricle is derived from the fetal atrium; it has rough myocardium known as pectinate muscles.
The sinus venarum is the smooth-walled portion of the atrium, which receives blood from the superior and inferior venae cavae. The crista terminalis is the vertical ridge that separates the smooth from the rough portion of the right atrium; it extends longitudinally from the superior vena cava to the inferior vena cava. The SA node is in the upper part of the crista terminalis. The right AV tricuspid valve communicates with the right ventricle.
Right Ventricle The right ventricle receives blood from the right atrium via the tricuspid valve; outflow is to the pulmonary trunk via the pulmonary semilunar valve. The trabeculae carneae are the ridges of myocardium in the ventricular wall.
The papillary muscles project into the cavity of the ventricle and attach to cusps of the AV valve by the strands of the chordae tendineae. Papillary muscles contract during ventricular contraction to keep the cusps of the AV valves closed.
The chordae tendineae control closure of the valve during contraction of the ventricle. The infundibulum is the smooth area of the right ventricle leading to the pulmonary valve. Left Atrium The left atrium receives oxygenated blood from the lungs via the pulmonary veins. There are four openings: the upper right and left and the lower right and left pulmonary veins.
The left AV orifice is guarded by the mitral bicuspid valve; it allows oxygenated blood to pass from the left atrium into the left ventricle. Left Ventricle Blood enters from the left atrium through the mitral valve and is pumped out to the aorta through the aortic valve. Trabeculae carneae, the ridges of myocardium in the ventricular wall, are normally three times thicker than those of the right ventricle. Papillary muscles usually two large ones are attached by the chordae tendineae to the cusps of the bicuspid valve.
The aortic vestibule leads to the aortic semilunar valve and ascending aorta; the right and left coronary arteries originate from the right and left aortic sinuses at the root of the ascending aorta. Clinical Correlation Murmurs Murmurs in valvular heart disease result when there is valvular insufficiency or a stenotic valve. The posterior surface is formed mainly by the left atrium. A diaphragmatic surface is formed primarily by the left ventricle. All rights reserved. The atrioventricular node receives the impulse from the sinoatrial node and transmits that impulse to the ventricles through the bundle of His.
The bundle divides into the right and left bundle branches and Purkinje fibers to the two ventricles. Sympathetic innervation from the T1 to T5 spinal cord segments increases the heart rate, while the parasympathetics by way of the vagus nerves slow the heart rate. Surgical neck fracture of humerus Superior thoracic artery Thoracoacromial artery Teres major Midshaft fracture of humerus Supra-condylar fracture of humerus Aortic arch Pectoralis minor Lacerates profunda brachii artery may lesion radial n.
Lateral circumflex artery Medial circumflex artery Major source of blood supply to head of femur Deep femoral artery Supplies anterior and posterior thigh and shaft of femur Lateral thoracic artery Lacerates brachial artery may lesion median n. Medial epicondyle fracture Radial collateral artery Superior ulnar collateral artery may lesion ulnar n. Subscapular artery anastomoses with suprascapular artery to provide collateral circulation around the axillary artery Popliteal artery Popliteal artery Anterior tibial artery Inferior ulnar collateral artery Radial artery Common interosseus artery Ulnar artery Posterior tibial artery Compressed with tibial nerve in posterior compartment syndrome Anterior tibial artery Compressed with deep fibular nerve in anterior compartment syndrome Peroneal artery Deep palmar arch Superficial palmar arch Medial plantar artery Dorsalis pedis artery Lateral plantar artery Plantar arch artery Anterior Posterior Figure III In fact, the abnormal shape of action potentials initiated during the relative refractory period reduces calcium influx and thus contractile force, as shown.
A depolarizing wave moving away from the positive toward the negative terminals produces a negative deflection. A wave of depolarization moving at right angles to the axis of the electrode terminals produces no deflection. Upon repolarization, the reverse occurs. Intersection of the CFC and VFC is the stable operating point; if contractility or blood volume changes, the system will operate at the intersection of the two new curves.
Point A: venous pressure is increased from 3 to 6 mm Hg because of sudden removal of blood from arterial system and injection into venous system. This causes CO to increase to point B. Send-to-Kindle or Email Please login to your account first Need help? Please read our short guide how to send a book to Kindle.
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