Unit 2- Histology Flashcards
Tissue Defenition
a collection of specialized cells and cell products that perform a limited number of functions
Types of tissues
connective, muscle, epithelial, nervous
Connective Tissue Basic Components
- Specialized cells
- extracellular protein fibers
- a fluid called ground substance
Extracellular Matrix:
a) any part of tissue located outside of the cells
b) Matrix is a mix of specialized fibers and specific fluid for the type of tissue
Specialized Cells Categories:
- Fixed
- Wandering
Fixed Specialized Cells Roles:
-responsible for local maintenance and repair
-energy storage
Fixed Specialized Cells Components:
-fibroblasts
- adipocytes
- mesenchymal cells
Wandering Specialized Cells Roles:
-defend and repair damaged tissue
-migrate through healthy tissue
-aggregate at injury
Wandering Specialized Cells Components:
-phagocytic (macrophages and macrophages)
-mast cells
-lymphocytes
-plasma
Fibroblasts Function
-most abundant permanent residents
-always in connective tissue
-secrete proteins and all types of fibers
make ground substance viscous
Adipocytes Components:
-adipose cells (fat cells)
-single enormous lipid droplet
-nucleus organelles shifted to one side
Connective Tissue Fibers
-made by protein from fibroblasts
-collagen
-reticular
-elastic
Collagen Fibers:
-most common
-long, straight, unbranched
-flexible but stronger than steel
Reticular Fibers:
-narrower protein fibers and in branching network
-anchor and support organs (keep them in place)
-ex. soft organs like liver and spleen
Elastic Fibers:
-elastin protein
-returns to original shape after compression or stretching
-found in skin and elastic ligaments of vertebrae
Ground Substance:
-fills spaces between cells & surrounds fibers
-secreted by fibroblasts
-made of polysaccharides
-determines how tissue will do its job
Types of Connective Tissue:
-Connective tissue proper
-Fluid connective tissue
-Supportive connective tissue
Connective Tissue Proper:
-syrupy/viscous ground substance
-Loose connective tissue
-Dense connective tissue
Fluid Connective Tissue:
-dense pop. of cells in a watery matrix
-blood
-lymph
Supportive Connective Tissue:
-less diverse cell pop.
-dense fibers
-Cartilage
-Bone
Loose Connective Tissue Functions:
-loose, open framework of fibers
-fills spaces, surrounds and supports blood vessels and nerves
-stores lipids and diffuses materials
Loose Connective Tissue Components:
-Adipose
-Areolar
-Reticular
Areolar Tissue Locations:
-deep to the skin
-mucous membranes
-around blood vessels, nerves, and organs
Areolar Tissue Organization:
-least specialized connective tissue
-loosely organized fibers
-extensive blood supply
viscous ground substance
Areolar Tissue Functions:
-ground substance absorbs shocks
-can distort shape and return to original shape ->elastic fibers
-separates skin from deeper tissue
-carries wandering cells to and from tissue
-epithelia rely on nutrients from capillaries
Adipose Tissue Organization:
-commonly called fat
-areolar tissue can become adipose tissue with ^ lipid levels
-adipocytes can be active (inflate) or inactive (deflate)
Brown Adipose Tissue:
-found in newborns and hibernating animals
-multiple lipid drops
-produce heat
Adipose Tissue Functions:
-padding
-cushion shocks
-insulates
-energy reserves
Adipose Tissue Locations:
-deep to skin
-sides, buttocks, breasts, around heart, eyes, & kidneys
White Adipose Tissue:
-single lipid drop
-most common in adults
-stores energy
Reticular Tissue Organization:
-fibroblasts create a network of reticular fibers
-only tissue where reticular fibers are predominant
-never see reticular tissue alone
Dense Connective Tissue Components:
-often called collagenous tissues or fibrous connective tissue
-strength, resists stretch
-fibroblasts and fibrocytes to generate collagen fibers
-flat and parallel to force
Reticular Tissue Functions:
-creates supporting framework for organs
-supports parenchyma
Red Blood Cells:
-erythrocytes
-transport O2 and CO2
Reticular Tissue Locations:
-liver
-kidney
-spleen
-lymph nodes
-bone marrow
Dense Regular Connective Tissue Functions:
-firm attachment
-conducts pull of muscles
-reduces friction
-stabilizes relative positions of bones
Dense Irregular Organizations:
-interwoven meshwork w no consistent pattern
Dense Irregular Locations:
-dermis
-perichondrium
-periosteum
-capsule
Dense Irregular Functions:
-made to support in multiple different directions
-prevents over expansion of organs
Platelets:
-not whole cells
-tiny, membrane enclosed packets of cytoplasm
-contain enzymes and proteins 4 clotting response
White Blood Cells:
-Leukocytes
-include michrophages, basophils, lymphocytes, monocytes
Creation of Blood:
-called hematopoiesis
-takes place in bone marrow of long bones and lymph nodes
Cartilage Components:
-dense matrix of collagen fibers
-rubbery ground substance
-only chondrocytes
-avascular
-Hyaline
-Elastic
-Cartilage
Hyaline Cartilage Functions:
-closely packed collagen fibers (cannot always see in slides)
-provide stiff but flexible support
-reduces friction between bony surfaces
Hyaline Cartilage Locations:
-between tips of ribs and bones of sternum
-covering bone surfaces at joints
-supporting larynx, trachea, bronchi
-part of nasal septum
-articular cartilages
Fibrocartilage Functions:
-little ground substance
-densely interwoven collagen fibers
-resists compression
-prevents bone-bone contact
-limits relative movement
Fibrocartilage Location:
-pads within knee joint
-between pubic bones
-intervertebral discs
Elastic Cartilage Functions:
-numerous elastic fibers
-provides support but tolerates distortion without damage
-
Elastic Cartilage Locations:
-external ear
-epiglottis
-ear canal
-cuneiform cartilages of larynx
Bone Tissue Components:
-osseous tissue
-matrix is made from calcium salts and collagen fibers
-Osteoblasts (active bonegrowth)
-Osteocytes (less active, maintenance)
-Osteoclasts (surface)
Osteon:
-rings of structure
Haversian canal:
-blood vessel; nerve
Canaliculi:
diffusion from lacunae(small chambers)
Lamellae:
- concentric circles
Muscle Tissue:
-responsible for movement
-cells have specialized organelles to allow for contraction
-skeletal
-cardiac
-smooth
Skeletal Muscle Functions:
- located in musculoskeletal system
-moves and stabilizes skeleton
-voluntary control of entrances and exits of respiratory, digestive, and urinary tracts
-generates heat
-protects internal organs
-can repair itself
Skeletal Muscle Components:
-striated
-long and thin
-multinucleate
-incapable of dividing
Cardiac Muscle Functions:
-located only in heart
circulate blood
-limited repairing ability
-maintain hydrostatic blood pressure
Cardiac Muscle Components:
-striated
-branched
-involuntary muscle
-pacemaker cells: cause heart to beat w/ nerve activity
Smooth Muscle Locations:
-wall of blood vessels
-digestive, respiratory, urinary, reproductive systems
Smooth Muscle Functions:
-move food, urine, and reproductive tract secretions
-controls diameter of respiratory passageways
-regulates diameter of blood vessels
Smooth Muscle Components:
-non striated
-tapered at the end, spindle shaped
-single nucleus
-involuntary muscle
-can divide and regenerate after injury
Neural Tissue Functions:
-specialized for conduction of electrical impulses
-rapidly senses internal and external environment
-processes info and controls responses
-tissue concentrated in brain and spine
-Neurons
-Neuroglial
Neurons:
-longest cell in body
-cannot divide
-limited ability to repair
Neuroglia:
-glial cells
-support, repair, provide, nourishment to neurons
-regulate composition of fluid surrounding neurons
-eat bacteria (phagocytosis)
Neuron Components:
-large cell body
-dendrites
-axon
-myelination
Dendrites:
-branching projections
-recievers of information
Axon:
-long “tail” of cell
-sometimes called nerve fibers
-conductors of information
Myelination:
-sheath increasing efficiency
-white matter has myelination
-grey matter does not
