Intro to Gross Anatomy

Card Set Information

Intro to Gross Anatomy
2015-05-19 21:18:50

Show Answers:

  1. What are bone cells called?
  2. What is bone comprised of?
    calcified connective tissue consisting of cells (osteocytes) embedded in a matrix of ground substance and collagen fibers, have a superficial thin layer of compact bone around a central mass of spongy bone, and contain internal soft tissue, the marrow, where blood cells are formed.
  3. What minerals are stored in bone?
    reservoir for calcium and phosphorus and act as biomechanical levers on which muscles act to produce the movements permitted by joints.
  4. How are bones classified?
    classified, according to shape, into long, short, flat, irregular, and sesamoid bones and, according to their developmental history, into endochondral and membranous bones.
  5. What are the long bones of the body?
    Include humerus, radius, ulna, femur, tibia, fibula, metacarpals, and phalanges
  6. How do long bones develop?
    by replacement of hyaline cartilage plate (endochondral ossification)
  7. What are the main parts of long bones?
    shaft (diaphysis) and two ends (epiphyses). The metaphysis is a part of the diaphysis adjacent to the epiphyses.
  8. Diaphysis
    Forms the shaft (central region) and is composed of a thick tube of compact bone that encloses the marrow cavity.
  9. Metaphysis
    Is a part of the diaphysis, the growth zone between the diaphysis and epiphysis during bone development.
  10. Epiphyses
    Are expanded articular ends, separated from the shaft by the epiphyseal plate during bone growth and composed of a spongy bone surrounded by a thin layer of compact bone.
  11. Short bones
    • Include the carpal and tarsal bones and are approximately cuboid shaped.
    • Are composed of spongy bone and marrow surrounded by a thin outer layer of compact bone.
  12. Flat bones
    • Include the ribs, sternum, scapulae, and bones in the vault of the skull.
    • Consist of two layers of compact bone enclosing spongy bone and marrow space (diploë).
    • Have articular surfaces that are covered with fi brocartilage and grow by the replacement of connective tissue.
  13. Irregular bones
    • Include bones of mixed shapes such as bones of the skull, vertebrae, and coxa.
    • Contain mostly spongy bone enveloped by a thin outer layer of compact bone.
  14. Sesamoid bones
    • Develop in certain tendons and reduce friction on the tendon, thus protecting it from excessive wear.
    • Are commonly found where tendons cross the ends of long bones in the limbs, as in the wrist and the knee (i.e., patella).
  15. What are the roles of osteoblasts and osteoclasts?
    Osteoblast synthesizes new bone and osteoclast functions in the resorption (break down bone matrix and release calcium and minerals) and remodeling of bone.
  16. What hormones affect the skeletal system?
    Parathyroid hormone causes mobilization of calcium by promoting bone resportion, whereas calcitonin suppresses mobilization of calcium from bone.
  17. What is osteoid?
    Osteoid is the organic matrix of bone prior to calcification.
  18. What is osteomalacia?
    Osteomalacia is a gradual softening of the bone due to failure of the bone to calcify because of lack of vitamin D or renal tubular dysfunction.
  19. What is osteopenia?
    Osteopenia is a decreased calcification of bone or a reduced bone mass due to an inadequate osteoid synthesis.
  20. What is osteoporosis?
    • Osteoporosis is an age-related disorder characterized by decreased bone mass and increased susceptibility to fractures of the hip, vertebra, and wrist. It occurs when bone resorption outpaces bone formation, since bone constantly undergoes cycles of resportion and formation (remodeling) to maintain the con-centration of calcium and phosphate in the extracellular fluid.
    • Signs of osteoporosis are vertebral compression, loss of body height, development of kyphosis, and hip fracture.
  21. What is osteopetrosis?
    Osteopetrosis is an abnormally dense bone, obliterating the marrow cavity, due to defective resportion of immature bone.
  22. What is Hilton's Law?
    The nerve supplying a joint also supplies the muscles that move the joint and the skin covering the insertion of such muscles
  23. What are the 3 types of joint classifications?
    Classified on the basis of their structural features into fibrous, cartilaginous, and synovial types.
  24. What are the 2 types of fibrous joints (Synarthroses)?
    • 1. Sutures
    • 2. Syndesmoses
    • Are joined by fibrous tissue, have no joint cavities, and permit little movement.
  25. Sutures
    Are connected by fibrous connective tissue and found between the flat bones of the skull.
  26. Syndesmoses
    • connected by fibrous connective tissue.
    • Occur as the inferior tibiofibular, radioulnar, and tympanostapedial syndesmoses.
  27. What are the two types of cartilaginous joints?
    • Are united by cartilage and have no joint cavity.
    • 1. Primary Cartilaginous Joints (Synchondroses)
    • 2. Secondary Cartilaginous Joints (Symphyses)
  28. Primary Cartilaginous Joints (Synchondroses)
    • Are united by hyaline cartilage and permit no movement but growth in the length.
    • Include epiphyseal cartilage plates (the union between the epiphysis and the diaphysis of a growing bone) and sphenooccipital and manubriosternal synchondroses.
  29. Secondary Cartilaginous Joints (symphyses)
    • Are joined by fibrocartilage and are slightly movable joints.
    • Include the pubic symphysis and the intervertebral disks.
  30. Synovial (Diarthrodial) Joints
    • Permit a great degree of free movement and are classified according to the shape of the articulation and/or the type of movement.
    • Are characterized by four features: joint cavity, articular (hyaline) cartilage, synovial membrane (which produces synovial fluid), and articular capsule.
  31. What are the 6 types of Synovial Joints?
    • 1. Plane (Gliding) Joints
    • 2. Hinge (Ginglymus) Joints
    • 3. Pivot (Trochoid) Joints
    • 4. Condylar (Ellipsoidal) Joints
    • 5. Saddle (Sellar) Joints
    • 6. Ball-and-Socket (Spheroidal or Cotyloid) Joints
  32. Plane (Gliding) Joints
    • Are united by two flat articular surfaces and allow a simple gliding or sliding of one bone over the other.
    • Occur in the proximal tibiofibular, intertarsal, intercarpal, intermetacarpal, carpometacarpal, sternoclavicular, and acromioclavicular joints.
  33. Hinge (Ginglymus) Joints
    • Resemble door hinges and allow only flexion and extension.
    • Occur in the elbow, ankle, and interphalangeal joints.
  34. Pivot (Trochoid) Joints
    • Are formed by a central bony pivot turning within a bony ring and allow only rotation (movement around a single longitudinal axis).
    • Occur in the superior and inferior radioulnar joints and in the atlantoaxial joint.
  35. Condylar (Ellipsoidal) Joints
    • Have two convex condyles articulating with two concave condyles. (The shape of the articulation is ellipsoidal.)
    • Allow flexion and extension and occur in the wrist (radiocarpal), metacarpophalangeal, knee (tibiofemoral), and atlantooccipital joints.
  36. Saddle (Sellar) Joints
    • Resemble a saddle on a horse’s back and allow flexion and extension, abduction and adduction, and circumduction but no axial rotation.
    • Occur in the carpometacarpal joint of the thumb and between the femur and patella.
  37. Ball-and-Socket (Spheroidal or Cotyloid) Joints
    • Are formed by the reception of a globular (ball-like) head into a cup-shaped cavity and allow movement in many directions.
    • Allow flexion and extension, abduction and adduction, medial and lateral rotations, and circumduction and occur in the shoulder and hip joints.
  38. Osteoarthritis
    • Noninflammatory degenerative joint disease characterized by degeneration of the articular cartilage and osseous outgrowth at the margins.
    • It results from wear and tear of the joints; commonly affects the hands, fingers, hips, knees, feet, and spine; and is accompanied by pain and stiffness.
  39. Rheumatoid arthritis
    • An inflammatory disease primarily of the joints. It is an autoimmune disease in which the immune system attacks the synovial membranes and articular structures, leading to deformities and disability.
    • There is no cure for rheumatoid arthritis, and its most common symptoms are joint swelling, stiffness, and pain.
  40. Gout
    A painful form of arthritis and is caused by too much uric acid in the blood. Uric acid crystals are deposited in and around the joints, causing an inflammation and pain, heat, redness, stiffness,  tenderness, and swelling of the joint tissues.
  41. What are the 3 types of muscles?
    • 1. Skeletal
    • 2. Cardiac
    • 3. Smooth
  42. Skeletal Muscles
    Is voluntary and striated; makes up approximately 40% of the total body mass; and functions to produce movement of the body, generate body heat, and maintain body posture.
  43. How are muscles attached?
    Has two attachments, an origin (which is usually the more fixed and proximal attach-ment), and an insertion (which is the more movable and distal attachment).
  44. What is the basic structure of skeletal muscle?
    Is enclosed by epimysium, a thin layer of connective tissue. Smaller bundles of muscle fibers are surrounded by perimysium. Each muscle fiber is enclosed by endomysium.
  45. Lou Gehrig's disease (amyotrophic lateral sclerosis)
    • A fatal neurologic disease that attacks the neurons responsible for controlling voluntary muscles.
    • The muscles gradually weaken and atrophy; the brain is unable to control voluntary movement of the arms, legs, and body; and patients lose the ability to breath, swallow, and speak. The earliest  symptoms may include cramping, twitching, and muscle weakness.
  46. Cardiac Muscle
    • Is involuntary and striated and forms the myocardium, the middle layer of the heart.
    • Is innervated by the autonomic nervous system but contracts spontaneously without any nerve supply.
    • Includes specialized myocardial fibers that form the cardiac conducting system
  47. Smooth Muscle
    • Is involuntary and nonstriated and generally arranged in two layers, circular and longitu-dinal, in the walls of many visceral organs.
    • Is innervated by the autonomic nervous system, regulating the size of the lumen of a tubular structure.
    • Undergoes rhythmic contractions called peristaltic waves in the walls of the gastrointestinal (GI) tract, uterine tubes, ureters, and other organs.
  48. Tendons
    • Are fibrous bands of dense connective tissue that connect muscles to bones or cartilage.
    • Are supplied by sensory fibers extending from muscle nerves.
  49. Ligaments
    Are fibrous bands that connect bones to bones or cartilage or are folds of peritoneum serving to support visceral structures.
  50. Raphe
    Is the line of union of symmetrical structures by a fibrous or tendinous band such as the pterygomandibular, pharyngeal, and scrotal raphes.
  51. Aponeuroses
    Are flat fibrous sheets or expanded broad tendons that attach to muscles and serve as the means of origin or insertion of a flat muscle.
  52. Retinaculum
    Is a fibrous band that holds a structure in place in the region of joints.
  53. Bursae
    Are fluid-filled flattened sacs of synovial membrane that facilitate movement by minimizing friction.
  54. Synovial Tendon Sheaths
    Are synovial fluid-filled tubular sacs around muscle tendons that facilitate movement by reducing friction.
  55. What are the two types of Fascia?
    • 1. Superficial Fascia
    • 2. Deep Fascia
    • A fibrous sheet that envelops the body under the skin and invests the muscles and may limit the spread of pus and extravasated fluids such as urine and blood.
  56. Superficial Fascia
    Is a loose connective tissue between the dermis and the deep (investing) fascia and has a fatty superficial layer (fat, cutaneous vessels, nerves, lymphatics, and glands) and a membranous deep layer.
  57. Deep Fascia
    • Is a sheet of fibrous tissue that invests the muscles and helps support them by serving as an elastic sheath or stocking.
    • Provides origins or insertions for muscles, forms fibrous sheaths or retinacula for tendons, and forms potential pathways for infection or extravasation of fluids.
  58. Nervous System
    • Is divided anatomically into the central nervous system (CNS), consisting of the brain and spinal cord, and the peripheral nervous system (PNS), consisting of 12 pairs of cranial nerves and 31 pairs of spinal nerves, and their associated ganglia.
    • Is composed of neurons and neuroglia (nonneuronal cells such as astrocytes, oligodendro-cytes, and microglia) and controls and integrates the body activity.
  59. Nervous system subdivision
    Is divided functionally into the somatic nervous system, which controls primarily voluntary activities, and the visceral (autonomic) nervous system, which controls primarily involuntary activities.
  60. Neurons
    • Are the structural and functional units of the nervous system (neuron doctrine).
    • Are specialized for the reception, integration, transformation, and transmission of infor-mation.
  61. What are the 3 components of Neurons?
    • 1. Cell bodies
    • 2. Dendrites
    • 3. Axons
  62. Cell bodies
    located in the gray matter of the CNS, and their collections are called ganglia in the PNS and nuclei in the CNS.
  63. Dendrites
    usually short and highly branched and carry impulses toward the cell body.
  64. Axons
    usually single and long, have fewer branches (collaterals), and carry impulses away from the cell body.
  65. What are the 3 classifications of Neurons?
    • 1. Unipolar (pseudounipolar) neurons
    • 2. Bipolar neurons
    • 3. Multipolar neurons
  66. Unipolar (Pseudounipolar) Neurons
    • Have one process, which divides into a central branch that functions as an axon and a peripheral branch that serves as a dendrite.
    • Are called pseudounipolar because they were originally bipolar, but their two processes fuse during development to form a single process that bifurcates at a distance from the cell body.
    • Are sensory neurons of the PNS and found in spinal and cranial nerve ganglia.
  67. Bipolar Neurons
    Have two processes (one dendrite and one axon); are sensory; and are found in the olfactory epithelium, the retina, and the inner ear.
  68. Multipolar Neurons
    Have several dendrites and one axon and are most common in the CNS (e.g., motor cells in anterior and lateral horns of the spinal cord, autonomic ganglion cells).
  69. Ganglion vs Nucleus
    • Is a collection of neuron cell bodies outside the CNS
    • A nucleus is a collection of neuron cell bodies within the CNS.
  70. Cells that support neurons
    • Include Schwann cells and satellite cells in the PNS.
    • Are called neuroglia in the CNS and are composed mainly of three types: astrocytes; oligodendrocytes, which play a role in myelin formation and transport of material to neurons; and microglia, which phagocytose waste products of nerve tissue.
  71. Myelin
    • Is the fat-like substance forming a sheath around certain nerve fibers.
    • Is formed by Schwann cells in the PNS and oligodendrocytes in the CNS.
  72. Synapses
    • Are the sites of functional contact of a neuron with another neuron, an effector (muscle, gland) cell, or a sensory receptor cell.
    • Are classified by the site of contact as axodendritic, axoaxonic, or axosomatic.
    • Subserve the transmission of nerve impulses, commonly from the axon terminals (pre-synaptic elements) to the plasma membranes (postsynaptic elements) of the receiving cell.
  73. Brain
    • Is enclosed within the cranium, or the brain case.
    • Has a cortex, which is the outer part of the cerebral hemispheres, and is composed of gray matter. This matter consists largely of the nerve cell bodies, dendrites, and neuroglia.
    • Has an interior part composed of white matter, which consists largely of axons forming tracts or pathways, and ventricles, which are filled with cerebrospinal fluid (CSF).
  74. Spinal cord
    • Is cylindrical, occupies approximately the upper two-thirds of the vertebral canal, and is enveloped by the meninges.
    • Has cervical and lumbar enlargements for the nerve supply of the upper and lower limbs.
    • Has centrally located gray matter, in contrast to the cerebral hemispheres, and peripher-ally located white matter.
    • Grows more slowly than the vertebral column during fetal development, and hence, its terminal end gradually shifts to a higher level.
    • Has a conical end known as the conus medullaris and ends at the level of L2 (or between L1 and L2) in the adult and at the level of L3 in the newborn.
  75. Meninges
    • Consist of three layers of connective tissue membranes (pia, arachnoid, and dura mater) that surround and protect the brain and the spinal cord.
    • Contain the subarachnoid space, which is the interval between the arachnoid and pia mater, filled with CSF.
  76. Cranial Nerves
    • Consist of 12 pairs and are connected to the brain rather than to the spinal cord.
    • Have motor fibers with cell bodies located within the CNS and sensory fibers with cell bodies that form sensory ganglia located outside the CNS.
    • Emerge from the ventral aspect of the brain (except for the trochlear nerve, cranial nerve IV).
  77. Spinal Nerves
    • Consist of 31 pairs: 8 cervical, 12 thoracic, 5 lumbar, 5 sacral, and 1 coccygeal.
    • Are formed from dorsal and ventral roots; each dorsal root has a ganglion that is within the intervertebral foramen.
  78. How are spinal nerves connected?
    • Are connected with the sympathetic chain ganglia by rami communicantes.
    • Contain sensory fibers with cell bodies in the dorsal root ganglion (general somatic affer-ent [GSA] and general visceral afferent [GVA] fibers), motor fibers with cell bodies in the anterior horn of the spinal cord (general somatic efferent [GSE] fibers), and motor fibers with cell bodies in the lateral horn of the spinal cord (general visceral efferent [GVE] fi b-ers) between T1 and L2.
    • Are divided into the ventral and dorsal primary rami. The ventral primary rami enter into the formation of plexuses (i.e., cervical, brachial, and lumbosacral); the dorsal primary rami innervate the skin and deep muscles of the back.
  79. What are the 7 functional components in peripheral nerves?
    • 1. General somatic afferent fibers
    • 2. General somatic efferent fibers
    • 3. General visceral afferent fibers
    • 4. General visceral efferent fibers (Autonomic nerves)
    • 5. Special somatic afferent fibers
    • 6. Special visceral afferent fibers
    • 7. Special visceral Efferent fibers
  80. General Somatic Afferent Fibers
    Transmit pain, temperature, touch, and proprioception from the body to the CNS.
  81. General Somatic Efferent Fibers
    Carry motor impulses to the skeletal muscles of the body.
  82. General Visceral Afferent Fibers
    Convey sensory impulses from visceral organs to the CNS.
  83. General Visceral Efferent Fibers (Autonomic Nerves)
    Transmit motor impulses to smooth muscle, cardiac muscle, and glandular tissues
  84. Special Somatic Afferent Fibers
    Convey special sensory impulses of vision, hearing, and equilibration to the CNS.
  85. Special Visceral Afferent Fibers
    Transmit smell and taste sensations to the CNS.
  86. Special Visceral Efferent Fibers
    • Conduct motor impulses to the muscles of the head and neck.
    • Arise from branchiomeric structures such as muscles for mastication, muscles for facial expression, and muscles for elevation of the pharynx and movement of the larynx.
  87. Autonomic Nervous System
    • Is divided into the sympathetic (thoracolumbar outflow), parasympathetic (craniosacral outflow), and enteric divisions.
    • Is composed of two neurons, preganglionic and postganglionic, which are GVE neurons.
  88. Sympathetic nerve fibers
    • Have preganglionic nerve cell bodies that are located in the lateral horn of the thoracic and upper lumbar levels (L2 or L1–L3) of the spinal cord.
    • Have preganglionic fibers that pass through ventral roots, spinal nerves, and white rami communicantes. These fibers enter adjacent sympathetic chain ganglia, where they synapse or travel up or down the chain to synapse in remote ganglia or run further through the splanchnic nerves to synapse in collateral ganglia, located along the major abdominal blood vessels.
    • Have postganglionic fibers from the chain ganglia that return to spinal nerves by way of gray rami communicantes and supply the skin with secretory fi bers to sweat glands, motor fi bers to smooth muscles of the hair follicles (arrectores pilorum), and vasomotor fibers to the blood vessels.
  89. When are sympathetic nerve fibers used?
    Function primarily in emergencies or catabolism (energy consumption), preparing individuals for fight or flight, and thus increase the heart rate, inhibit GI motility and secretion, and dilate pupils and bronchial lumen. They liberate norepinephrine (except sweat glands) and are classified as adrenergic.
  90. Parasympathetic Nerve Fibers
    • Comprise the preganglionic fibers that arise from the brain stem (cranial nerves III, VII, IX, and X) and sacral part of the spinal cord (second, third, and fourth sacral segments).
    • Are, with few exceptions, characterized by long preganglionic fibers and short postganglionic fibers.
    • Are distributed to the walls of the visceral organs and glands of the digestive system but not to the skin or to the periphery.
    • Decrease the heart rate, increase GI peristalsis, and stimulate secretory activity.
    • Function primarily in homeostasis or anabolism (energy conservation), tending to promote quiet and orderly processes of the body. They liberate acetylcholine and are classified as cholinergic.
  91. Enteric Division
    • Consists of enteric ganglia (parasympathetic postganglionic neuron cell bodies) and plexus of the GI tract, including the myenteric (Auerbach’s) and submucosal (Meissner’s) plexuses.
    • Plays an important role in the control of GI motility and secretion.
  92. Vascular System
    • Functions to transport vital materials such as oxygen, nutrients, and waste products, including carbon dioxide, hormones, defense elements, and cells involved in wound healing.
    • Consists of the heart and vessels (arteries, capillaries, veins) that transport blood through all parts of the body.
    • Includes the lymphatic vessels, a set of channels that begin in the tissue spaces and return excess tissue fluid to the bloodstream.
  93. Pulmonary Circulation
    Transports blood from the right ventricle through the pulmonary arteries to the lungs for the exchange of oxygen and carbon dioxide and returns it to the left atrium of the heart through the pulmonary veins.
  94. Systemic Circulation
    Transports blood from the left ventricle through the aorta to all parts of the body and returns it to the right atrium through the superior and inferior venae cavae and the cardiac veins.
  95. Heart
    • Is a hollow, muscular, four-chambered organ that pumps blood to two separate circulatory loops, the pulmonary circulation and the systemic circulation.
    • Is regulated in its pumping rate and strength by the autonomic nervous system, which controls a pacemaker (i.e., sinoatrial node).
  96. Blood Vessels
    • Carry blood to the lungs, where carbon dioxide is exchanged for oxygen.
    • Carry blood to the intestines, where nutritive materials in fl uid form are absorbed, and to the endocrine glands, where hormones pass through the vessel walls and are distributed to target cells
    • Transport the waste products of tissue fluid to the kidneys, intestines, lungs, and skin, where they are excreted.
    • Are of four types: arteries, veins, capillaries, and sinusoids.
  97. Arteries
    • Carry blood from the heart to the capillary beds and have thicker walls than do veins.
    • Consist of three main types: elastic arteries, muscular arteries, and arterioles
  98. Capillaries
    • Are composed of endothelium and its basement membrane and connect the arteri-oles to the venules.
    • Are the sites for the exchange of carbon dioxide, oxygen, nutrients, and waste prod-ucts between the tissues and the blood.
    • Are absent in the cornea, epidermis, and hyaline cartilage and may be absent in some areas where the arterioles and venules have direct connections (arteriovenous anastomoses or shunts), which may occur in the skin of the nose, lips, fingers, and ears, where they conserve body heat.
  99. Veins
    • Return blood to the heart from the capillary beds and consist of the pulmonary veins, which return oxygenated blood to the heart from the lungs, and the systemic veins, which return deoxygenated blood to the heart from the rest of the body.
    • Contain valves that prevent the reflux of blood and have venae comitantes that closely accompany muscular arteries in the limbs.
  100. Sinusoids
    • Are wider and more irregular than capillaries and substitute for capillaries in some organs, such as the liver, spleen, red bone marrow, adenohypophysis, suprarenal cortex, and parathyroid glands.
    • Often contain phagocytic cells on their walls and form a part of the reticuloendothelial system, which is concerned chiefly with phagocytosis and antibody formation.
  101. Portal System
    Is a system of vessels in which blood collected from one capillary network passes through a large vessel(s) and then a second capillary network before it returns to the systemic circulation.
  102. What are the two portal systems?
    • Hepatic portal system in which blood from the intestinal capillary bed passes through the hepatic portal vein and then hepatic capillaries (sinusoids) to the hepatic veins
    • Hypophyseal portal system in which blood from the hypothalamic capillaries passes through the hypophyseal portal veins and then the pituitary capillary sinusoids to the hypophyseal veins.
  103. Lymphatic system
    • Provides an important immune mechanism for the body.
    • Is involved in the metastasis of cancer cells and provides a route for transporting fat and large protein molecules absorbed from the intestine to the thoracic duct.
  104. Lymphatic Vessels
    • Serve as one-way drainage toward the heart and return lymph to the bloodstream through the thoracic duct (the largest lymphatic vessel) or the right lymphatic duct.
    • Are not usually visible in dissections but are the major route by which cancer metasta-sizes.
  105. How do lymphatic vessels function?
    • Function to absorb large protein molecules and transport them to the bloodstream because the molecules cannot pass through the walls of the blood capillaries back into the blood.
    • Carry lymphocytes from lymphatic tissues to the bloodstream.
    • Have valves, which are constricted at the sites of valves, showing a beaded appearance.
    • Are absent in the brain, spinal cord, eyeballs, bone marrow, splenic pulp, hyaline carti-lage, nails, and hair.
  106. Lymphatic Capillaries
    • Begin blindly in most tissues, collect tissue fluid, and join to form large collecting vessels that pass to regional lymph nodes.
    • Absorb lymph from tissue spaces and transport it back to the venous system.
    • Are called lacteals in the villi of the small intestine, where they absorb emulsified fat.
  107. Lymph Nodes
    • Are organized collections of lymphatic tissue permeated by lymph channels.
    • Produce lymphocytes and plasma cells and filter the lymph.
    • Trap bacteria drained from an infected area and contain reticuloendothelial cells and phagocytic cells (macrophages) that ingest these bacteria.
    • Are hard and often palpable when there is a metastasis and are enlarged and tender during infection.
  108. Lymph
    • Is a clear, watery fluid that is collected from the intercellular spaces. Contains no cells until lymphocytes are added in its passage through the lymph nodes. Its constituents are similar to those of blood plasma (e.g., proteins, fats, lymphocytes).
    • Often contains fat droplets (called chyle) when it comes from intestinal organs.
    • Is filtered by passing through several lymph nodes before entering the venous system.
  109. What are the 3 divisions of the digestive system?
    the mouth, the pharynx, and the alimentary canal, comprising the esophagus, the stomach, the small intestine, and the large intestine.