Knowledge of anatomy and anatomical language can help ensure consistency and accuracy when discussing the human body.

Body regions

Anatomical Terms of Location

Here is the standard anatomical position which is used for reference in human anatomy.

Planes and then directions. Using Tait-Bryan angles and the right-hand rule: X-axis is front and back, Y-axis is left and right, and Z-axis is up and down.

Relative Directions

Movements

Health Systems of the Human Body

The human organism is broken down into systems, then organs, then tissues, then cells, and then chemical. There are different opinions on the number of systems in systemic anatomy:

Here are some details on some of the systems.

  1. Skeletal. 206 bones in a typical adult. [Yes, I contribute to the Human skeleton [W] article at Wikipedia.]
    • Axial skeleton. 80 bones.
      • Skull. 22.
        • Skull, left lateral view Skull, anterior view Head and neck, right lateral view of muscles nad nerves
        • Cranial bones. 8.
          • Frontal  bone = forehead and eyebrow ridge. 1.
          • Parietal bones = side and upper back corners. 2.
          • Temporal bones = side and base around the ear. 2.
          • Occipital bone = lower back and base. 1.
          • Ethmoid  bone = separates brain from nasal cavity. Between the frontal and sphenoid. 1.
          • Sphenoid bone = front base and sides. Between the temporal, occipital, and ethmoid. 1.
        • Facial. 14.
          • Zygomatic bones = cheek bones. Part of the orbit. Touches the frontal, sphenoid, temporal, and maxilla. 2.
          • Nasal bone = bridge of the nose. 2.
          • Maxilla = upper jaw. The sides of the nose too. 1.
          • Mandible = lower jaw. 1.
          • Palatine bone = part of the roof of the mouth, the bottom of the orbital and nasal cavities. Between the maxilla and spehnoid. 2.
          • Lacrimal bone = front inner part of the orbit. Smallest of the facial bones. 2.
          • Vomer bone. Forms a vertical wall above the mandible but in the nasal cavity. 1.
          • Inferior nasal conchae. Spongy bone in the nasal cavity. 2.
      • Ossicles = bones of the middle ear. 2*3 = 6.
        • Malleus = hammer. Attached to the eardrum and the incus. 2.
        • Incus = anvil. Attached to the malleus and stapes. 2.
        • Stapes = stirrup. Attached to the incus and the inner ear. 2.
      • Hyoid bone = bone at the throat. 1.
      • Vertebral column. 33 vertebrae but some are fused. 26.
        • Cervicle vertebrae = neck = {C1=Atlas, C2=Axis, C3-C7}. 7.
        • Thoracic vertebrae = middle spine = T1-T12. 12.
        • Lumbar vertebrae = lower spine = L1-L5. 5.
        • Sacrum = base of spine = S1-S5 are fused. 1.
        • Coccyx = tailbone = Co1-Co4 are fused. 1.
      • Thorax = chest. 25
        • Sternum = breastbone. 1.
        • Ribs. 2*12 = 24.
          • True ribs = pairs I-VII. Attached directly to the sternum. 2*7 = 14.
          • False ribs = pairs VIII-X. Attached via cartiage to a rib above. 2*3 = 6.
          • Floating ribs = pairs XI-XII. Attached only to the vertebrae. 2*2 = 4.
    • Appendicular skeleton. 126 bones.
      • Shoulder girdle. 2*2 = 4
        • Clavicle = collar bone. Articulated at the sternum and the the clavicle suspends the scapula (at the acromioclavicular joint = AC joint). The only bone without marrow. 2.
        • Scapula = shoulder blade. 2.
      • Arm. 2*3 = 6.
        • Humerus = upper arm. Articulated with the scalpula (at the glenohumeral joint = shoulder joint, and supported by the group of muscles and tendons called the rotator cuff) and with the ulna and radius. 2.
        • Ulna = pinky side of forearm. 2.
        • Radius = thumb side of forearm. 2.
      • Hand. 2*27 = 54.
        • Carpal = wrist bones. Arranged in two rows of four. 2*8 = 16.
          • Bones in the proximal/wrist-side row (from radial/thumb/lateral to ulnar/pinky/medial): scaphoid, lunate, triquetral and pisiform. 2*4 = 8.
          • Bones in the distal/hand-side row (from radial/thumb/lateral to ulnar/pinky/medial): trapezium, trapezoid, capitate and hamate. 2*4 = 8.
        • Metacarpal = palm bones = I-V (from radial/thumb/lateral to ulnar/pinky/medial). 2*5 = 10.
        • Phalanges = finger bones = digit bones. 2*14 = 28.
          • Proximal and distal thumb bones. 2*2 = 4.
          • Proximal, intermediate, and distal finger bones. 2*4*3 = 24.
      • Pelvic girdle. 2.
        • Each half of the pelvis is actually a fusion of three bones:
          • Illium = illium = the broad wings. 2*1/3 = 2/3.
          • Pubis = the top half of the lower loop. 2*1/3 = 2/3.
          • Ischium = the bottom half of the lower loop. 2*1/3 = 2/3.
      • Leg. 2*4=8.
        • Femur = thigh bone. 2.
        • Patella = kneecap. 2.
        • Tibia = shin bone. 2.
        • Fibula = calf bone. 2.
      • Foot. 52.
        Foot bones, left foot, lateral view [via http://en.wikipedia.org/wiki/Image:Gray291.png]
        • Tarsal = ankle bones. 2*7 = 14.
          • Calcaneus = heel bone. The largest tarsal. Equivalent to the hock of digitigrade quadrupeds, such as a horses or dogs. 2.
          • Talus. Connects the leg to the foot. The second largest tarsal. 2.
          • Navicular bone. Medial and in front of the talus. 2.
          • Cuneiform bones = medial, intermediate, and lateral cuneiform bones. 2*3 = 6.
          • Cuboidal bone. Lateral. Between the calcaneus and metatarsals IV and V. 2.
        • Metatarsal = instep bone = I-V (from medial/great toe to lateral/pinky toe). 2*5 = 10.
        • Phalanges = toe bones. These actually run from toe to "ankle". 2*14 = 28.
  2. Muscular.
    • Usually a primary muscle (agonist) and secondary muscles (synergists) constrict while an opposing muscle (antagonist) relaxes.
    • Excercise can cause a build up of lactate in muscles. Contrary to popular belief lactate usually does not change into lactic acid (lactate's acidic form), rather when aerobic processes become anaerobic, there is a rapid builds up of ATP, and by that point the tissue can't buffer it quickly enough, which results in a drop in pH (i.e. an increase in acidity or a state of acidosis) which causes a burning pain!
    • Most exercises deal directly with skeletal muscles (as opposed to the cardiac muscles of the heart or the smooth muscles of the intestines and blood vessels).
      • Type I. Red-twitch. Lots of myoglobin making them "red" and good for aerobic, long period, endurance activities.
      • Type II. White-twitch. Less myoglobin making them "white" and good for anaerobic, brief period, high strength and speed activities.
    • Ten major skeletal muscle groups:
      • Lower body. Also the glutes (buttocks) are nearby.
        • 1. Quadriceps. Front of thighs.
        • 2. Hamstrings. Back of thighs.
        • 3. Calves.
      • Upper body. Also the  forearms, and trapezius (neck and upper back).
        • 4. Pectorals. Chest.
        • 5. Lats. Mid to upper back.
        • 6. Deltoids. Shoulders.
        • 7. Triceps. Back of upper arms.
        • 8. Biceps. Front of upper arms.
      • Middle body. Also the hip flexors.
        • 9. Abdominals. Belly.
        • 10. Lower back.
  3. Cardiovascular. Heart and blood vessels.
  4. Respiratory. Breathing.
    • Nasal cavity.
    • Mouth.
    • Pharynx.
    • Epiglottis. This cartilage is the flap which is normally up to allow breathing but is pulled into a more horizontal position for swallowing.
    • Larynx = voicebox.
    • Trachea = windpipe.
    • Lungs.
      • Bronchi.
        • Alveoli.
  5. Nervous. Brain. Nerves. Eyes.
    • Cranial Nerves. 12 pairs emerge directly from the brain. All belong to the peripheral nervous system (PNS), except for the olfactory and optic nerves which belong to the central nervous system (CNS).
      1. Olfactory nerve. Part of the central nervous system.
      2. Optic nerve. Part of the central nervous system.
      3. Oculomotor nerve
      4. Trochlear nerve. More eye nerves.
      5. Trigeminal nerve. Facial sensation and mastication.
      6. Abducent nerve. Another eye nerve.
      7. Facial nerve. Facial expression, taste, and salivation.
      8. Vestibulocochlear nerve. Sound rotation, and gravity.
      9. Glossopharyngeal nerve. Taste.
      10. Vagus nerve. Speech, heartrate, sweating, gastrointestinal. Arguably the single most important nerve in the body. It runs from the medulla oblongata of the brainstem, along the esophagus, provides parasympathetic innervation for the heart, and terminates at the stomach.
      11. Accessory nerve. Neck.
      12. Hypoglossal nerve. Tongue.
    • Spinal Nerves. Emerge from the brain, to the spine, and out from the spine.
    • Central Nervous System (CNS)
      • Brain
      • Spinal Cord
    • Peripheral Nervous System (PNS)
      • Somatic Nervous System (SNS). Regulates activities under conscious control, movement, and receiving external stimuli.
        • Sensory System
          • Visual System
          • Auditory System
          • Olfactory System. Smell.
          • Gustatory System. Taste.
          • Nociceptor. Pain.
          • Thermoreceptor. Temperature.
          • Vestibular. Movement, orientation, and balance.
          • Mechanoreceptor. Mechanical pressure or distortion.
      • Autonomic Nervous System (ANS). Regulates activities under subconscious control. Some of the functions like breathing and blinking are partially under conscious control too.
        • Sympathetic Nervous System (SNS again!). Responds to danger and stress (the "flight or fight" response) including adrenaline. It includes major neural plexuses: Cervical plexus, Brachial plexus, Lumbar plexus, Sacral plexus, and Celiac plexus = solar plexus.
          Sympathetic Nervous System (SNS)
        • Parasympathetic Nervous System (PNS again!). Deals with rest and relaxation (the "rest and digest" response).
        • Enteric Nervous System (ENS). Deals with digestion from intake to output.
    • Miscellany
      • Major neural plexuses:
        • Cervical plexus.
        • Brachial plexus.
        • Lumbar plexus.
        • Sacral plexus.
        • Celiac plexus = solar plexus.
      • Afferent nerves. Aka sensory nerves; receptor nerves. Carry nerve impulses from receptors or sensory organs toward the central nervous system.
      • Efferent nerves. Aka motor nerves; effector nerves. Carry nerve impulses from the central nervous system towards effectors such as muscle, glands, or the inner ear.
  6. Integumentary. Skin, Nails, & Hair. The skin is the largest organ of the body.
  7. Digestive = Digestive Tract = Gastrointestinal Tract = GI Tract
    • Mouth
    • Pharynx. Area just behind the mouth and above the esophagus.
    • Esophagus
    • Stomach
    • Small intestine. Made up of the duodenum, the jejunem, and the ileum.
    • Large intestine. Made up of the caecum, the colon, and the rectum.
    • Anus
    • Three related organs
      • Liver. Makes bile (which aids in digestion) and has a lot of functions affecting the metabolism. EG: The metabolism of amino acids forms ammonia, which the liver detoxifies into urea, (NH2)2CO; Interestingly birds and reptiles make uric acid instead and fish excrete ammonia directly. EG: While a meal is digested, the glucose in the blood rises so the liver takes insulin from the pancreas and stores up excess glucose as glycogen; After a meal is digested, the glucose in the blood drops, the liver stops making glycogen; Four hours after a meal, the liver starts breaking down its glycogen store to provide glucose to the blood. The liver is the second largest organ of the body and the largest gland. It is located under diaphragm and right of the stomach.
      • Gallbladder. Stores bile until needed. The gall bladder is cupped by the liver.
      • Pancreas. Makes enzymes for digestion (esp. insulin) and hormones that affect metabolism. The pancrease is just behind the stomach, is nestled by the dudenum of the small intestine, and extends from the middle of the body and passes in front of the left kidney.
  8. Reproductive. Sex organs.
  9. Immune.
  10. Urinary.
    • Kidneys. The kidneys, like the lungs, intestine, and skin, handle wastes. The kidneys regulate electrolytes in the blood and hence affect the acidity and pH balance of the blood. The kidneys also dispose of the urea from the liver.
    • Ureters. Tubes that carry urine from the kidneys to the bladder.
    • Bladder. Stores urine.
  11. Endocrine. Hormones.

Page Modified: (Hand noted: 2007-11-03 22:26:10Z) (Auto noted: 2008-11-25 16:54:45Z)