Medical Imaging Techniques Quiz

Medical Imaging

• Medical imaging is a technique used to create images of the human body to help visualize structures and diagnose illnesses.

Techniques of Medical Imaging

• Radiography (X-rays): produces a 2D image of interior structures, inexpensive and quick, used to examine hollow structures, bones, and soft tissues.
• Magnetic Resonance Imaging (MRI): uses a powerful magnetic field to differentiate between different tissues, including tumors, brain abnormalities, and blood flow.
• Computed Tomography (CT): uses a computer to assemble x-rays into a 3D image, used to visualize soft tissues in more complex detail, and detect lung and kidney cancers.
• Ultrasound: uses high-frequency sound waves, noninvasive and painless, used to monitor fetal development.
• Endoscopy: uses a lighted instrument with a lens to project an image onto a monitor.
• Colonoscopy: examines the interior of the colon.
• Laparoscopy: examines the organs within the abdominal cavity.
• Arthroscopy: examines the interior of a joint.

Types of Radiographic Images

• Angiogram: shows the human heart and any blockage in the coronary artery.
• Mammogram: shows the female breast and any cancerous tumors.
• Bone Densitometry: shows the lumbar spine.
• Barium Contrast x-ray: shows the ascending colon and any cancerous tumors.
• Intravenous Urogram: shows the right kidney and any kidney stones.

Directional Terms

• Proximal: position further from a point.
• Distal: closer to the midline.
• Ipsilateral: same side of the body.
• Contralateral: opposite side of the body.
• Superficial: closer to the surface of the body.
• Deep: further from the surface of the body.
• Anterior (ventral): toward or at the front of the body.
• Posterior (dorsal): toward or at the back of the body.
• Medial: closer to the midline of the body.
• Lateral: farther from the midline of the body.
• Intermediate: between two structures.

Planes and Sections

• Body Planes: imaginary flat surfaces that separate the body or body part into portions.
• Sagittal (Midline): divides the body into right and left sides.
• Transverse (Horizontal): divides the body into superior and inferior portions.
• Frontal (Coronal): divides the body (or an organ) into anterior (front) and posterior (back) portions.

Examples of Planes

• Midsagittal Section: a midsagittal section of the human brain.
• Frontal (Coronal) Section: a frontal or coronal brain section.
• Transverse (Horizontal) Section: a transverse or horizontal brain section.

Anatomy Terminology

Levels of Organisation in the Human Body

• Chemical Level: atoms (C, H, O, N, P) and molecules (DNA).
• Cellular Level: smooth muscle cell.
• Tissue Level: smooth muscle tissue.
• Organ Level: salivary glands, pharynx (throat), mouth, esophagus, liver, gallbladder, stomach, pancreas, small intestine, large intestine, epithelial and connective tissues, smooth muscle tissue layers.
• System Level: digestive system.
• Organismal Level.

Homeostasis

Cycle of Events

• The body is constantly monitored and re-monitored.
• Each monitored variable is called a controlled condition.

Three Basic Components

• Receptor: sensitive to changes in the environment.
• Control Center: receives input from the receptor and provides output.
• Effector: brings about a change to the controlled condition.

Feedback Principles

• Negative Feedback: a stimulus disrupts homeostasis by increasing or decreasing a controlled condition.
• Positive Feedback: a stimulus disrupts homeostasis by increasing or decreasing a controlled condition.

Control of Homeostasis

• Example 1: Blood Pressure:
  • Stimulus: increasing blood pressure.
  • Receptor: baroreceptors in certain blood vessels send nerve impulses to the brain.
  • Control Center: the brain interprets input and sends nerve impulses to the heart.
  • Effector: the heart decreases its heart rate, decreasing blood pressure.
  • Response: blood pressure decreases back to normal.
• Example 2: Childbirth:
  • Stimulus: increasing stretching of the cervix.
  • Receptor: stretch-sensitive nerve cells in the cervix send nerve impulses to the brain.
  • Control Center: the brain interprets input and sends oxytocin through the bloodstream.
  • Effector: muscles in the wall of the uterus contract more forcefully, pushing the baby's body against the cervix.
  • Response: the cervix stretches more, further stimulating oxytocin release and causing increasingly strong contractions, leading to birth.