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.