Basal Humanbiologi Histologi (væv)

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Basal Humanbiologi

Histology (tissue)

Tissue: an aggregate of cells usually of a particular kind together with their intercellular substance (matrix) that form one of the structural materials of an animal.

Epithelial tissue

always has free surface, underside anchored to connective tissue – basement membrane. Lack blood vessels, tightly packed – form protective barrier. Readily divide. (Cover body surfaces, internal organs, compose glands) (Protection, secretion, absorption, excretion) Name: single layer (simple), multi layer (stratified), flattened (squamous), cuboidal, columnar.

Goblet cells: secrete protective fluid, mucus onto the free surface of epithelial tissue.

Basement tissue: nonliving layer where epithelial tissues anchor to connective tissue.

Simple squamous epithelium: Diffusion, filtration, covers surface. Air sacs of lungs, capillaries.
Simple cuboidal epithelium: Secretion, absorption. (linings of kidney tubules, ducts of glands)
Simple columnar epithelium: thick, protect underline tissues, absorption, secretion. (ciliated) lunge, female reproductive tubes.(nonciliated) secrete digestive fluid, absorb nutrients. Microvilli process increase surface area, better absorption.
Pseudostratified columnar epithelium: protection, secretion, have cilia, form respiratory passage. Mucus on cilia by goblet sells, sweeps away. Appear stratified bc nucleus located at dif. lvls.
Stratified squamous epithelium: Protection, cells divide in deeper layers, newer cells push older ones farther outwards, become flattened. (epidermis) produce keratin as cell ages, harden and die, dry, tough, protective material. Oral cavity, vagina, anal channel outer cells are not keratinized.
Stratified cuboidal epithelium: Protection. Forms lining of a lumen (cavity of a tubular organ) – mammary glands, sweat glands, salivary glands, pancreas.
Stratified columnar epithelium: Protection, secretion. Form urethra, vas deferens
Transitional epithelium: Distensibility, protection. Specialized to change in response to increased tension – urinary bladder. Forming barrier prevent diffusion.
Glandular Epithelium: specialized to secrete substances. Usually cuboidal, columnar.

  • Exocrine glands: secrete product into ducts that open onto some internal, external surface.
    • Merocrine glands: secret fluid without loss of cytoplasm, exocytosis; watery, protein rich. (Salivary glands, pancreatic glands, sweat glands)
      • serous cell: secrete, watery high concentration of enzymes. (Body cavity)
      • mucous cell: rich in glycoprotein – mucin. (Digestive, respiratory)
    • Apocrine glands: lose small portion of sell body during secretion (mammary)
    • Holocrine glands: release entire cell with secretory product, disintegrate.
  • Endocrine glands: secrete product into tissue fluid or blood.

Connective tissue:

bind structure, provide support, protection, fill spaces, store fat, produce blood cells, anti infections, help repair tissue damage. More matrix than epithelia. Good vascularity.

Major Cell Types

Fibroblasts: ground substance in C. tissue, large, star shaped, produce fibers, and secrete protein.
Macrophages: motile, specialized in phagocytosis, defensive cell originate as white blood cell.
Mast cell: near blood vessels, release heparin => anti blood clotting, histamine => allergy.


Collagenous fibers: thick threads of protein collagen, grouped in long paralleled bundles. Flexible but only slightly elastic, great tensile strength, good at hold stuff together, e.g. ligaments, tendons.
Elastic fibers: microfibrils embedded in elastin, weaker than collagen, but stretch easily and can resume position and shapes. Frequently stretched, vocal cords.
Reticular fibers: supporting network, e.g. beneath basement membrane with blood vessels


Areolar tissue (loose connective tissue): bind organs together; hold tissue fluids, good vascularity to nourish, e.g. epithelial. Mainly fibroblasts, separated by gellike matrix collagenous and elastic fibers. Beneath skin, between muscles, beneath epithelial tissue in various joints.
Adipose tissue: specialized loose c. tissue. Protect, insulate, and store fat. Beneath skin, behind kidneys, eyeballs, heart surface.
Dense connective tissue: binds organs together. Tendons, ligaments. Many collagenous fibers! Poor blood supply, slow repair.


Cartilage: rigid C. tissue, mainly collagenous fibers, embedded in gellike ground substance. Enclosed by perichondrium, blood supply, nurture by diffusion. Lack of direct blood supply, slow healing, chondrocytes don’t divide often. (external ear, respiratory passage, joints)
Hyaline cartilage: fine collagenous fibers in matrix. Support, protect, provide framework. Nose.
Elastic cartilage: dense network of elastic fibers. Support, protect, more flexible framework. Ears.
Fibro cartilage: Many collagenous, very tough. Support, protect, absorbs shock. Intervertebral discs


Bone: Most rigid, hardness due to minerals between cells, matrix has abundant collagen fibers, flexible, reinforce mineral components. Osteocytes located in lacunae, evenly spaced between lamellae, form concentric pattern – central channels, each with one blood vessel. Cytoplamic process, canaliculi – material moves faster between blood vessels. HEAL FASTER
Osteon: a system of cylinder-shaped unit, by osteocytes and layers of intercellular material concentrically clustered around a central canal. Many osteon together form bone.


Blood: composed of red blood cells, white blood cells, blood plasma (fluid matrix), platelets.

Muscle Tissue

Skeletal: attach to bones, voluntary. Nerve impulse stimulate muscle fiber contraction. Striated.
Smooth: Involuntary movement of internal organs, non-striated. Spindle shaped cell.
Cardiac: Striated, joined end-to-end, involuntary.

Nervous Tissue

contain neurons (also neuroglial cells), transmit impulses by cellular processes to other neurons, muscles or glands – can coordinate, regulate, and integrate body functions.
Neuroglial cell: carry on phagocytosis, supply nutrients to neurons.