Anatomy and Physiology - Flashcards

Homeostasis

  • Homeostasis is the body's ability to maintain a relatively stable internal environment despite external changes.
  • It involves continuous monitoring and regulation of various factors (variables).
  • Examples of factors include fluid volume and chemical composition.
  • Homeostasis maintains a steady state, a balance, or equilibrium.
  • Failure to maintain homeostasis leads to illness, disease, and potentially death.

Homeostatic Control

  • Homeostatic control isn't precise; it maintains a normal range rather than an absolute value.
  • Example: Blood pH ranges from 7.35 to 7.45; the set point is 7.4.
  • Involves feedback mechanisms:
    • Receptor (sensor): Detects changes (stimuli) in the internal or external environment.
    • Control center: Receives and processes information from the receptor and sends out a command.
    • Effector: Responds to the command by opposing the stimulus.

Negative Feedback

  • Negative feedback loops provide stability and are the primary means of maintaining homeostasis.
  • Example: Body temperature regulation
    • Body temperature exceeds 37^{\circ}C. Nerve cells in skin and brain detect this.
    • Information is sent to the temperature regulatory center in the brain.
    • The brain sends signals to sweat glands to perspire, cooling the body through evaporation.
  • Homeostasis is not precise; there's oscillation around the set point.

Positive Feedback

  • Positive feedback enhances or exaggerates the original stimulus.
  • It can create a cascade or amplification effect, accelerating a process to completion.
  • Example: Childbirth
    • The brain stimulates the pituitary gland to secrete oxytocin.
    • Oxytocin travels to the uterus via the bloodstream.
    • Oxytocin stimulates uterine contractions, pushing the baby toward the cervix.
    • The baby's head pushing against the cervix triggers nerve impulses to the brain.
    • Once the baby is born (stimulus removed), the process stops.
  • Positive feedback mechanisms often activate self-perpetuating events.
  • Most positive feedback mechanisms aren't related to maintaining homeostasis.
  • Blood clotting is another example.
  • Homeostatic mechanisms are generally maintained through negative feedback.

Anatomical Terms

  • Anatomy uses a specialized language with Latin and Greek origins.
  • Knowing anatomical terms is crucial for studying anatomy and physiology.

Key Aspects

  • Word roots, prefixes, and suffixes.
  • Regional terms indicating body locations.
  • Directional terms used for points of reference.

Examples

  • Cardio-: heart
  • Endo-: within
  • Hemo-: blood
  • Myo-: muscle

Anatomical Position

  • Standardized way of viewing the body for precision.
  • Body standing upright with feet at shoulder width and parallel, toes facing forward.
  • Upper limbs held to each side, palms facing forward.
  • Lying down:
    • Prone: Face down
    • Supine: Face up

Regional Terms

  • Used to indicate locations on or in the body.
    • Abdominal: Anterior torso below the diaphragm.
    • Brachial: Arm.
    • Axillary: Armpit.
    • Buccal: Cheek.
    • Coxal: Hip.

Directional Terms

  • Describe specific points of reference on the body.
    • Anterior (ventral): Toward or at the front of the body.
    • Posterior (dorsal): Toward or at the back of the body.
    • Superior (cranial): Above, toward the head.
    • Inferior (caudal): Below, away from the head.
    • Medial: Toward the midline of the body.
    • Lateral: Away from the midline of the body.
    • Proximal: Closer to the origin of a body part.
    • Distal: Farther from the origin of a body part.
    • Superficial (external): Toward the body surface.
    • Deep (internal): Away from the body surface.

Sectional Planes

  • Sagittal plane: Divides the body into right and left parts.
    • Midsagittal plane: Divides the body exactly in the midline.
    • Parasagittal plane: Any sagittal plane offset from the midline.
  • Frontal (coronal) plane: Divides the body into anterior and posterior portions.
  • Transverse (horizontal) plane: Divides the body into superior and inferior portions.
  • Oblique: A cut made diagonally between horizontal and vertical planes (not shown).

Body Cavities

  • Protect internal organs from shock and allow for shape changes.

Dorsal Body Cavity

  • Composed of two smaller cavities:
    • Cranial cavity: Contains the brain.
    • Vertebral cavity: Contains the spinal cord.

Ventral Body Cavity (Coelom)

  • Houses internal organs (viscera or guts).
    • Thoracic cavity:
      • Pleural cavities (right and left): Contain the lungs.
      • Mediastinum: Space between pleural cavities containing the thymus, lymph vessels, esophagus, trachea, and nerves.
    • Abdominal cavity: Contains digestive organs.
    • Pelvic cavity: Contains the bladder, reproductive organs, and rectum.

Serous Membranes

  • Line the ventral body cavities.
  • Double-layered:
    • Parietal layer: Outer layer, toward the body wall.
    • Visceral layer: Inner layer, toward the organs.
  • Serous fluid: Watery, lubricating fluid between parietal and visceral layers.

Abdominopelvic Quadrants

  • Right Upper Quadrant (RUQ): Liver.
  • Left Upper Quadrant (LUQ): Stomach and spleen.
  • Left Lower Quadrant (LLQ): Descending colon.
  • Right Lower Quadrant (RLQ): Cecum and ascending colon.

Abdominopelvic Regions

  • Umbilical region: Centermost, surrounding the navel.
  • Epigastric region: Superior to the umbilical region.
  • Hypogastric region: Inferior to the umbilical region.
  • Right and left hypochondriac regions: Flank the epigastric region laterally.
  • Right and left lumbar regions: Lateral to the umbilical region.
  • Right and left iliac (inguinal) regions: Lateral to the hypogastric region.

Serous Membranes Details

  • Visceral layer: Toward the organ.
  • Parietal layer: Lining the body wall.
  • Example: Heart
    • Parietal pericardium: Lines the pericardial cavity.
    • Visceral pericardium.
  • Between the visceral and parietal layers is serous fluid.

Medical Imaging

  • Non-invasive ways to view the human body.

Types of Medical Imaging

  • X-ray machines
  • CT machines
  • MRI machines
  • PET machines
  • Ultrasonography

X-Ray

  • High-energy electromagnetic radiation to see internal structures like bones.

Other Imaging Techniques

  • CT scan: Transverse sections of the head.
  • MRI: Uses a magnetic field.
  • PET scan: Shows active blood flow or organ activity.
  • Ultrasound: Used to monitor pregnancies due to its non-invasive nature and lack of harmful radiation.