Lab Practical 1 Study Guide

Anatomical Terminology:

• Posterior: Toward the dorsal (back) side
• Anterior: Toward the ventral (front) side
• Inferior: Toward the tail or feet
• Superior: Toward the head
• Medial: Toward the median plane
• Lateral: Away from the median plane
• Proximal: Toward the site of attachment
• Distal: Away from the site of attachment
• Intermediate: In between

11 Major Organ Systems of the Human Body

Integumentary:

Principal organs: skin, hair, nails, cutaneous glands

Principal functions: Protection, water retention, thermoregulation

Vitamin D synthesis, cutaneous sensation, nonverbal communication

Skeletal:

Principal organs: Bones, cartilages, ligaments

Principal functions: Support, movement, protective enclosure of viscera,

Blood formation, mineral storage, electrolyte and acid-base balance

Muscular:

Principal organs: skeletal muscles

Principle functions: movement, stability, communication, control of body openings, heat production

Lymphatic:

Principal organs: Brain, spinal cord, nerves, ganglia

Principal functions: Rapid internal communication, coordination, motor control and sensation

Endocrine:

Principal organs: Pituitary gland, thyroid gland, pineal glands, thymus, adrenal glands, pancreas, testes, ovaries

Principal functions: Hormone production, internal chemical communication and coordination

Circulatory:

Principal organs: Heart, blood vessels

Principal functions: Distribution of nutrients, oxygen, wastes, hormones, electrolytes, heat, immune cells and antibodies; fluid, electrolyte and acid-base balance

Lymphatic:

Principal organs: Lymph nodes, lymphatic vessels, thymus, spleen, tonsils

Principal functions: recovery of excess tissue fluid, detection of pathogens, production of immune cells, defense against disease

Respiratory:

Principal organs: nose, pharynx, larynx, trachea, bronchi, lungs

Principal functions: absorption of oxygen, discharge of carbon dioxide, acid-base balance, speech

Urinary:

Principal organs: Kidneys, ureters, urinary bladder, urethra

Principal functions: elimination of wastes, regulation of blood volume and pressure, stimulation of red blood cell formation, control of fluid, electrolyte and acid-base balance, detoxification

Digestive:

Principal organs: teeth, tongue, salivary glands, esophagus, small and large intestines, liver, gallbladder, pancreas

Principal functions: nutrient breakdown and absorption. Liver functions include: metabolism of carbohydrates, lipids, proteins, vitamins, and minerals; synthesis of plasma proteins, disposal of drugs, toxins, and hormones; cleansing of blood

Male reproductive:

Principal organs: testes, epididymides, spermatic ducts, seminal vesicles, prostate, bulbourethral glands, penis

Principal functions: production and delivery of sperm; secretion of sex hormones

Female reproductive:

Principal organs: ovaries, uterine tubes, uterus, vagina, mammary glands

Principal functions: production of eggs; site of fertilization and fetal development; fetal nourishment, birth, lactation, secretion of sex hormones

Microscopy

• Goal: create a magnified image that is too small to be seen with the naked eye
• Allows visualization of cell morphology and their organization into a tissue
• Three factors that determine the quality of a microscopic image
  • Magnification: increase in image size
  • Resolution: ability to distinguish detail
  • Contrast: ability to distinguish objects from the background
• Brightfield microscopes use a combination of glass lenses and light to view a specimen
• Fields of study where microscopy is necessary:
  • Cytology: the study of cells
  • Histology: the study of tissues
  • Pathology: the study of disease
• Four broad categories of tissues:
  • Epithelial tissue
  • Connective tissue
  • Nervous tissue
  • Muscle tissue
• Terms to know:
  • Apical surface: The surface of an epithelial cell facing the lumen or external environment
  • Basal surface: The surface of an epithelial cell facing the basement membrane
  • Basement membrane: found underneath the epithelial and underlying connective tissue layers; composed on non-cellular layers of collagen, glycoproteins and proteoglycans. Aids in attachment of epithelial tissue and as a selective molecular barrier to underlying connective tissue
  • Lumen: Central cavity or open space within an organ

Epithelial Tissue:

• Covers body surfaces and lines the insides of our hollow organs
• Form in sheets of cells that border a lumen (an open space)
• Cell shapes include:
  • Squamous: flat/ scale like
  • Cuboidal: cube shaped
  • Columnar: column like
  • Transitional: changes shape from polyhedral to flat
• Tissue layers include:
  • Simple: a single layer of cells
  • Stratified: multiple layers of cells
  • Pseudostratified: Single layer of cells that appears to be multiple layers
• Naming an epithelial tissue consists of naming the number of layers and the cell shape

Simple Epithelial Tissues

• Simple squamous epithelium
  • Structure: single layer of thin, flat cells resembling irregular floor tiles; the single nucleus of each cell bulges at its center
  • Function: Thinnest possible barrier to allow for rapid diffusion and filtration; secretion in serous membranes
  • Location: Air sacs in lungs (alveoli); lining of lumen of blood vessels and lymph vessels (endothelium) serous membranes of body
• Simple cuboidal epithelium
  • Structure: single layer of cells about as tall as they are wide; spherical and centrally located nucleus
  • Function: absorption and secretion; forms secretory tissue of most glands and small ducts
  • Location: Kidney tubules, thyroid gland follicles; surface of ovary; secretory regions and ducts of most glands
• Simple columnar epithelium
  • Structure: single layer of cells taller than they are wide; oval shaped nucleus oriented lengthwise in basal region of cell; apical regions of cell may have microvilli; may contain goblet cells that secrete mucin
  • Function: absorption and secretion; secretion of mucin
  • Location: inner lining of most digestive tract (stomach, small and large intestine
• Nonciliated Pseudostratified Columnar Epithelium
  • Structure: Single layer of cells with varying heights; all cells connect to the basement membrane, but not all cells reach the apical surface; lacks goblet cells and cilia
  • Function: Protection
  • Location: Rare-lining of part of the male urethra and epididymis
• Ciliated Pseudostratified columnar epithelium
  • Structure: single layer of cells with varying heights; all cells connect to the basement membrane, but not all cells reach the apical surface; has goblet cells and cilia
  • Function: protection; secretion of mucin and movement of mucus along apical surface of epithelium by cilia
  • Location: lining of the larger airways of respiratory tract, including nasal cavity, part of pharynx, parts of larynx, trachea, and bronchi

Stratified epithelial tissues

• Stratified squamous epithelium:
  • Keratinized Stratified Squamous Epithelium
    • Structure: multiple cell layers; basal cells are cuboidal or polyhedral whereas apical cells are squamous; apical cells are dead and filled with the protein keratin
    • Function: protection of underlying tissue from abrasion
    • Location: epidermis
  • Nonkeratinized stratified squamous epithelium
    • Structure: multiple cell layers; basal cells are cuboidal or polyhedral whereas apical (superficial) cells are squamous; cells lack keratin; superficial cells are alive and kept moist
    • Function: Protection of underlying tissue from abrasion
    • Location: lining of oral cavity, part of pharynx, part of larynx, esophagus, lining of vagina and anus
• Stratified cuboidal epithelium
  • Structure: two or more layers of cells; cells at the apical surface are about as tall as they are wide
  • Function: Protection and secretion
  • Location: Ducts of most exocrine glands and ovarian follicles
• Stratified columnar epithelium
  • Structure: two or more layers of cells; cells at the apical surface are taller than they are wide
  • Function: Protection and secretion
  • Location: Large ducts of salivary glands, conjunctiva covering the eye, and membranous part of male urethra

Transitional Epithelium

• Structure: epithelial appearance varies, depending upon whether tissue is relaxed or distended; relaxed epithelium has cuboidal or polyhedral cells and the apical cells are large and rounded. Distended epithelium has flattened cells at the apical surface; some cells are binucleated
• Function: accommodates volume changes by distending or relaxing in the urinary bladder, ureters, and part of urethra
• Location: lining of the urinary bladder, ureter, and part of urethra

Connective Tissue

• Connective tissue is a diverse group of tissues that are found distributed widely throughout the body. The cells are typically separated by significant amounts of extracellular matrix and found deep to epithelial tissue
• Has diverse functions:
  • Support, protection, binding of structures, storage, transport, immune
• Terms to know:
  • Ground substance: noncellular material produced by the connective tissue; In combination with the protein fibers forms the extracellular matrix
  • Protein fibers: Fibers are made of protein and found outside of the cells. The protein fibers may provide strength or stretch for a tissue. In combination with the ground substance forms the extracellular matrix.
  • Collagen fibers: very strong unbranched “rope-like” proteins that provide strength and flexibility to a tissue.
  • Elastic fibers: composed of the protein elastin and provide stretch to a tissue
  • Reticular fibers: thin branched fibers similar to collagen, that provide a tough and flexible scaffold

Loose connective tissue proper

• Areolar tissue
  • Structure: abundant viscous ground substance; few collagen and elastic fibers; scattered fibroblasts; many blood vessels
  • Function: Protects tissues and organs; binds skin and some epithelia to deeper tissue
  • Location: papillary layer of the dermis, subcutaneous layer (deep to skin); surrounds organs, nerve cells, some muscle cells, and blood vessels
• Adipose tissue
  • Structure: closely packed adipocytes; nucleus pushed to edge of cell by large fat droplet; contains many blood vessels
  • Function: stores energy; insulates, cushions, and protects
  • Location: subcutaneous layer; surrounds and covers some organs
• Reticular tissue
  • Structure: Viscous ground substance; meshwork of reticular fibers, leukocytes, and some fibroblasts
  • Function: provides stroma (supportive framework) to lymphatic organs
  • Location: spleen, lymph nodes, and red bone marrow

Dense connective tissue proper

• Dense regular connective tissue
  • Structure: densely packed, parallel arrays of collagen fibers; fibroblasts squeezed between layers of fibers; scarce ground substance; limited blood supply
  • Function: attaches bone to bone (most ligaments) as well as muscle to bone (tendons); resists stress applied in one direction
  • Location: tendons (attach muscle to bone); ligaments (typically attach bone to bone)
• Dense irregular connective tissue
  • Structure: collagen fibers randomly arranged and clumped together; fibroblasts in spaces among fibers; more ground substance than in dense regular connective tissue; extensive blood supply
  • Function: Withstands stresses applied in all directions; durable
  • Location: most of dermis of skin; periosteum covering bone; perichondrium covering cartilage, epineurium covering nerves, epimysium covering skeletal muscle, some organ capsules
• Elastic connective tissue
  • Structure: predominantly composed of elastic fibers; fibroblasts occupy some spaces between the fibers
  • Function: allows for stretching and recoil
  • Location: Walls of elastic arteries (such as the aorta), trachea, vocal chords

Supporting connective tissue

• Cartilage
  • Hyaline cartilage
    • Structure: glassy appearing matrix; irregular chondrocytes in lacunae
    • Function: Provides support; forms most of fetal skeleton
    • Location: Tip of nose; trachea; most of larynx, costal cartilage; both the epiphyseal (growth) plates and articular ends of long bones; most of fetal skeleton
  • Fibrocartilage
    • Structure: readily visible, numerous, parallel collagen fibers with limited ground substance; large chondrocytes in lacunae
    • Function: resists compression; acts as shock absorber in some joints
    • Location: intervertebral discs; public symphysis; menisci of knee joints
  • Elastic cartilage
    • Structure: Abundant elastic fibers that form weblike mesh; closely packed chondrocytes in lacunae
    • Function: maintains shape while permitting extensive flexibility
    • Location: external ear; epiglottis of larynx
  • Bone
    • Structure: calcified extracellular matrix containing osteocytes trapped in lacunae; compact bone organized in osteons (concentric lamellae arranged around a central canal); spongy bone is a meshwork that has a different organization from compact bone; well vascularized
    • Function: provides levers for body movement, supports soft structures, protects organs, stores calcium and phosphorus; spongy bone contains hemopoietic tissue and is the site for hemopoiesis
    • Location: bones of the body

Fluid connective tissue

• Blood
  • Structure: contains formed elements (erythrocytes, leukocytes, and platelets); dissolved protein within a liquid ground substance called plasma
  • Function: erythrocytes transport respiratory gasses (oxygen and carbon dioxide); leukocytes help protect the body from infectious agents; and platelets help with blood clotting. Plasma transports nutrients, wastes, and hormones throughout the body
  • Location: Primarily within blood vessels and in the heart
• Lymph: lymph fluid is found within lymph vessels and derives from interstitial fluid. It is mostly water and dissolved solutes and typically no cellular components.

Nervous Tissue

• Composed of glial cells and neurons
• Neurons: receive and transmit nerve impulses
  • Located in the brain, spinal cord, and nerves
  • Structure: cell body and cell processes such as dendrites and an axon
    • Dendrites: receive information and transmit it to the cell body
    • Axon: transmits the nerve impulse away from the cell body to another cell, such as another neuron, muscle cell, or gland
• Multipolar neurons: most common structural type of neuron; make up motor neurons and interneurons. Contain multiple dendrites and a single axon
• Glial cells: protect and care for the neurons

Muscle Tissue

• Muscle tissue is unique in that its cells have the ability to contract when stimulated
• Muscle tissue allows for both voluntary and involuntary movement and heat generation
• Skeletal muscle
  • Attaches to bone or skin
  • Cells are long striated cylindrical cells and multinucleate
  • Function: voluntary movement of skeletal muscle
• Cardiac muscle
  • Found in the wall of the heart
  • Cells are short, branched, striated, and uni- or binucleate
  • Function: involuntary movement of heart muscle
• Smooth muscle
  • Found in the walls of most viscera
  • Cells are short with a fusiform shape, lack striations, and are uninucleate
  • Function: involuntary movement such as peristalsis of an organ or vasoconstriction of a blood vessel