Overview of the Human Body

Overview of the Human Body

Key Anatomical Terms

  • Homeostasis: The condition in which all of the body’s systems are balanced and working together to maintain internal stability.
  • Metabolism: Physical and chemical processes by which substances are broken down or transformed into energy or products for use by the body.
  • Organ: A structural unit in the human body that performs a specific function.
  • Tissue: A group of cells that perform a similar task.
  • Cell: The basic structural unit of the body that divides, develops, and dies, renewing tissues and organs.

Organization of Terms (Smallest to Largest)

  1. Cells
  2. Tissues
  3. Organs
  4. Body systems

Health of Body Systems

  • Signs: Objective information about a person’s health.
  • Symptoms: Subjective information about a person’s health.
  • Blood draws may be ordered in response to a patient’s symptoms.
  • Testing may also be ordered to monitor a patient’s treatment.

Anatomical Terms of Direction and Location

  • Superior: Toward the head.
  • Inferior: Away from the head.
  • Anterior (or ventral): The front of the body or body part.
  • Posterior (or dorsal): The back of the body.
  • Medial: Toward the midline of the body.
  • Lateral: To the side, away from the midline of the body.
  • Proximal: Closer to the torso.
  • Distal: Farther away from the torso or body part.

Integumentary System

  • Integument: A natural protective covering (i.e., the skin).
  • The skin is the largest organ in the human body.
  • Dilate: To widen.
  • Constrict: To narrow.
  • Capillary puncture is also called dermal puncture.
Phlebotomy Connection: Integumentary System
  • Allergies often cause symptoms that affect the integumentary system.
  • Blood tests such as IgE and complete blood count (CBC) may be ordered when allergies are suspected.

Musculoskeletal System

  • Joint: The place at which two bones meet.
  • Muscles: A group of tissues that provides movement of body parts, protection of organs, and creation of body heat.
Phlebotomy Connection: Musculoskeletal System
  • Erythrocyte Sedimentation Rate (ESR) measures the rate at which red blood cells settle to the bottom of a test tube.
  • Tests for muscle enzymes can determine if muscle tissue is being damaged or destroyed.
  • Tests for certain antibodies can aid in arthritis diagnosis.

Nervous System

  • Central Nervous System (CNS): The part of the nervous system that is composed of the brain and spinal cord.
  • Peripheral Nervous System (PNS): Part of the nervous system made up of the nerves that extend throughout the body.
Phlebotomy Connection: Nervous System
  • There is no blood test that can diagnose stroke.

Respiratory System

  • Respiration: The process of inhaling air into the lungs and exhaling air out of the lungs.
Phlebotomy Connection: Respiratory System
  • One common blood test related to the respiratory system is blood gas testing. Entry-level PBTs do not often collect blood for these tests.

Urinary System

Phlebotomy Connection: Urinary System
  • In addition to blood tests, urine tests are often used to diagnose kidney disorders.

Gastrointestinal System

  • Glucose: natural sugar.
Phlebotomy Connection: Gastrointestinal System
  • Blood tests for certain antibodies can help diagnose Crohn’s disease and ulcerative colitis.
  • Liver function panels help a provider determine if a patient’s liver is functioning properly.

Endocrine System

  • Hormone: A chemical substance created by the body that controls body functions.
  • Diabetes: A condition in which the pancreas produces too little insulin or does not properly use insulin.
  • Gestational diabetes: A form of diabetes associated with pregnancy.
Phlebotomy Connection: Endocrine System
  • Endocrine system blood tests that are not related to diabetes.

Reproductive System

  • The gonads are the male and female reproductive organs.
  • They produce sperm and ova, which are the male and female sex cells.
  • They also secrete hormones.
Phlebotomy Connection: Reproductive System
  • PSA is a blood test used to screen men for a possible marker of prostate cancer. It is not typically used for men under 30 to screen for testicular cancer.

Immune and Lymphatic Systems

  • Nonspecific immunity: A type of immunity that protects the body from disease in general.
  • Specific immunity: A type of immunity that protects the body against a particular disease that is invading the body at a given time.
  • Lymph: A clear yellowish fluid that carries disease-fighting cells called lymphocytes.
Phlebotomy Connection: Immune and Lymphatic Systems
  • Autoimmune conditions cause the body to attack its own cells or tissues.
  • Immunodeficiency is when the body does not respond or does not respond enough to true threats from pathogens.