Anatomy and physiology (mometrix)

• Standard anatomical position


  Person standing with feet facing forward about hip width apart, legs and torso completely upright, arms at their side with palms facing forward
• The three primary body planes


  • Sagittal/Lateral
  • Coronal/Frontal
  • Axial/Transverse
• Sagittal plane


  Divides the body or any body part vertically into right and left sections, runs parallel to the midline of the body
• Coronal (frontal) plane


  Divides the body or any body structure vertically into front and back (anterior and posterior) sections, runs vertically through the body at right angles to the side
• Transverse (horizontal) plane


  Divides the patient's body into imaginary upper (superior) and lower (inferior or caudal) halves
• Terms of direction


  • Medial
  • Lateral
  • Proximal
  • Distal
  • Anterior
  • Posterior
  • Cephalad
  • Caudad
  • Superior
  • Inferior
• Abdominal regions


  • Right hypochondriac
  • Epigastric
  • Left hypochondriac
  • Right lumbar
  • Umbilical
  • Left lumbar
  • Right iliac
  • Hypogastric
  • Left iliac
• Abdominal quadrants


  • Right upper quadrant (RUQ)
  • Right lower quadrant (RLQ)
  • Left upper quadrant (LUQ)
  • Left lower quadrant (LLQ)
• Ventral cavity


  Located on the anterior aspect of the trunk, comprises the thoracic and the abdominopelvic cavities, separated by the diaphragm
• Thoracic cavity


  Above the diaphragm, contains the lungs and the mediastinum
• Abdominopelvic cavity


  Extends below the diaphragm to the pelvic floor, contains the upper abdominal cavity and the lower pelvic cavity
• Dorsal cavity


  Located on the posterior (dorsal) aspect of the body, contains the brain and the spinal cord
• Cranial cavity


  Encased in cranial bones, contains the brain, 12 cranial nerves, and the pituitary gland
• Vertebral cavity


  Contains the vertebrae and the spinal cord
• Respiratory system organs


  • Nose
  • Mouth
  • Nasal cavity
  • Sinuses
  • Pharynx
  • Larynx
  • Trachea
  • Bronchial tree
  • Lungs
• Gas exchange


  Loading of oxygen into pulmonary blood, and the removal of carbon dioxide
• Thermoregulation


  Regulation of body temperature through the respiratory system
• Lung structure


  • Pleural lining
  • Bronchial tree
  • Alveoli
• Alveoli


  Microscopic pouches where gas exchange occurs, have a combined surface area of 70 m^2
• Breathing mechanism


  1. Diaphragm and intercostal muscles contract to increase thoracic cavity volume and decrease pressure, causing air to enter lungs (inspiration)

  2. Muscles relax to decrease thoracic cavity volume and increase pressure, causing air to leave lungs (expiration)
• Carbon dioxide produced during cellular respiration is transported away from cells and exhaled
• Thermoregulation by the circulatory system


  Blood vessels can constrict or dilate to conserve or release heat, and the exhalation of warm, moist air helps cool the body
• Nutrients


  Glucose, amino acids, fats
• Hormones


  Substances released by endocrine glands that reach target cells
• Lipid-soluble molecules


  Require a carrier protein to be transported in blood
• Thermoregulation by the circulatory system


  1. Heat exchange at skin surface

  2. Blood vessels dilate or constrict in response to brain signals

  3. Thermoreceptors detect temperature changes and send impulses to hypothalamus

  4. Hypothalamus sends signals to smooth muscles around arterioles

  5. Vasodilation allows more blood flow and heat loss

  6. Vasoconstriction reduces blood flow and heat loss

  7. Sweating and shivering also help control body temperature
• Heart


  • Composed of three layers: epicardium, myocardium, endocardium
  • Four-chambered organ: atria receive blood, ventricles pump blood
• Valves


  Tricuspid valve, pulmonary semilunar valve, mitral valve, aortic semilunar valve
• Blood flow through the heart


  1. Blood from body goes to right atrium

  2. Goes to lungs through pulmonary valve

  3. Blood from lungs goes to left atrium

  4. Pumped to body through aortic valve
• Endothelium


  • Inner lining of blood and lymphatic vessels, composed of endothelial cells
  • Acts as a selectively permeable barrier
  • Reduces friction between blood and vessel walls
  • Releases substances that cause vasoconstriction and inhibit blood clotting
• Blood pressure


  • Force per unit area exerted by blood on vessel walls
  • Systolic pressure is maximum during ventricular contraction
  • Diastolic pressure is minimum during ventricular relaxation
  • Normal adult blood pressure is 120/80 mmHg
• Electrical conduction system of the heart


  • Sinoatrial node, atrioventricular node, Bundle of His, bundle branches, Purkinje fibers
  • Generates and propagates electrical impulses that cause heart contractions
• ECG waves


  • P wave: atrial depolarization
  • QRS complex: ventricular depolarization
  • T wave: ventricular repolarization
• PR interval


  • Time from start of atrial depolarization to start of ventricular depolarization
  • Normal range is 0.12-0.20 seconds
• QRS complex


  • Indicates depolarization of ventricles
  • Normal duration is 0.06-0.10 seconds
• ST segment


  Period when ventricles are completely depolarized
• QT interval


  • Time for ventricular depolarization and repolarization
  • Normal range is 0.2-0.4 seconds
• Cardiac arrhythmias


  • Bradyarrhythmias (abnormally slow)
  • Tachyarrhythmias (abnormally fast)
  • Conduction irregularities
  • Premature contractions
• Supraventricular tachycardia


  Heart rate of 200-300 BPM, may have a sudden onset and result in congestive heart failure
• Premature contractions


  May arise from the atria or ventricles