tissues (lab practical)

Nervous Tissues

• Neuron

Characteristics:

• Cell body (soma) = star-shaped

• Branching dendrites from soma

• Extracellular matrix = glial cells (tiny dots)

Functions:

• Detect & send sensory info using electrical signals (action potentials) to the brain for interpretation & bodily response

Muscle Tissue (which one)

Skeletal

Characteristics

• Little extracellular matrix

• Long, cylindrical fibers (striated) (kind of look like ribbons)

• Multiple nuclei – small/flat on edges of fibers

Function

• aid in voluntary movement (attached to bones)

Muscle Tissue (which one)

Cardiac

Characteristics:

• Little extracellular matrix

• Shorter cells w/ smaller diameter

• Some have 1 nucleus, others have 2

• Branching fibers

• Intercalated disks – connect adjacent cells

• Striated fibers but less defined

Function:

• Allows the heart to pump blood throughout the body

Muscle Tissue (which one)

Smooth

Characteristics:

• Cells w/ little extracellular matrix

• Cells = small, slender, spindle-shaped

• Densely packed

• Cells have 1 nucleus

• NO striations

Functions:

Respiratory

• Passage with control

Transportation of substances

• (urinary)

• (circulatory)

• Digestive, Urinary, Reproductive, walls of the stomach, small intestine & esophagus (helps move food)

• Goosebumps

• Integumentary

Smooth Muscle in the Respiratory System

bronchiole

Regulates airflow: contraction & relaxation changes diameter

trachea

Lines the posterior wall

• when it contracts, it narrows the diameter of the trachea; this narrowing increases the force of expired air, which helps clear mucus & foreign particles (coughing)

Smooth Muscle in Circulatory System

Regulates blood flow & pressure via vasoconstriction & vasodilation

3 Components of the Connective Tissue

Cells:

• Fibroblast (primary; produces/maintains ECM),

• Immune system cells:

• Macrophages: phagocytosis

• Lymphocytes: ‘sentinels’; surveillance & response

• Mast cells: ‘recruiters’ of other immune cells; inflammatory regulation

Ground substance:

• jelly-like, transparent, colorless, fills gaps between fibers & cells

Fibers:

• Collagen: most abundant, very strong, helps maintain structural integrity of tissues

• Reticular: thin, delicate, form mesh-like networks

• Elastic: give stretching/bending properties to tissue

Connective Tissue Groups & Subcategories

Proper:

• Loose: (fewer fibers, holds organs in place, attaches epithelial tissue to other underlying tissues)

• Areolar, Reticular (& specialized), Adipose (& specialized)

• Dense: (more fibers, attaches muscles to bones, link bones together at joints)

• Regular, Irregular, Elastic

Specialized:

• Cartilage: (semi-solid matrix)

• Hyaline, Fibrocartilage, Elastic

• Bone (solid matrix)

• Blood (fluid)

Connective Tissue Functions

PTSSDRC

Protection (skeletal system)

Transportation & exchange (blood = nutrients, oxygen, waste [e.g., CO2], hormones, immune cells)

Storage & thermal insulation (adipose [fat] can serve as an energy source)

Support…internal structural framework (skeleton)

Defend body against pathogens (immune system cells in ECM)

Repairing…triggers inflammation & forms scar tissue to heal damaged areas of the body

Connects & binds other tissues

connective tissue (type)

Loose Areolar

Characteristics:

• ECM = lots of ground substance (white space), lots of reticular fibers, some elastic & collagen fibers

• Lots of fibroblasts, some macrophages, some mast cells, some WBCs, lots of blood vessels

• Found almost everywhere in the body

Function:

• ‘Universal packing material’ = fills spaces between organs & tissues to hold them in place (support/cushion)

connective tissue (type)

Loose Reticular

Characteristics:

• ECM = lots of reticular fibers (very thin, form a branching network), lots of ground substance

• Cells = fibroblasts (a.k.a. reticular cells; make reticular fibers), lots of WBCs

Functions:

• Supports & anchors immune cells (WBCs, lymphocytes, macrophages)

• Supports other cell types (kidney, liver)

• Filtration: in filtering organs (spleen, lymph nodes), the ‘mesh-like’ network traps & filters out pathogens & worn-out blood cells

connective tissue (type)

Loose Adipose (fat)

Characteristics:

• ECM = very little (very few fibers & ground substance)

• Lots of fat cells (adipocytes)

• Fat cells = large, open, have thin margins, very pale, thin rim of cytoplasm that encircles a large lipid droplet, have a small nucleus on periphery

Functions :

• Subcutaneous fat: energy source, thermal insulation, protects underlying organs

• Visceral fat: energy source, cushions organs; poses greater health risk (e.g., heart disease, type 2 diabetes, high blood pressure)

connective tissue (type)

Dense Regular

Characteristics:

• ECM = densely packed, parallel, often wavy collagen fibers

• Slender nuclei compressed between collagen bundles

• Very few blood vessels

Locations & Functions:

• Tendons (connect muscles to bone) & ligaments (connect bones to other bones)

• In tendons = transmit muscle forces to create movement

• In ligaments = provide stability to joints

connective tissue (type)

Dense Irregular

Characteristics:

• ECM = densely packed collagen fibers going in all directions, very little ground substance

• Few cells (mainly fibroblasts that produce the collagen & ground substance)

• Very few blood vessels Locations & Functions:

Location & Function

• Resists excessive stretching (dermis [thickest layer of skin]; hollow organs [e.g., stomach, small & large intestine]), protection (encapsulates organs [e.g., kidneys, liver, spleen])

connective tissue (type)

Dense Elastic

Characteristics:

 ECM = rich in elastin fibers, some collagen fibers

 Some cells (fibroblasts [produce fibers])

Locations & Function:

 Allows organs (e.g., aorta, pulmonary trunk, pulmonary arteries, major arterial branches) to stretch/expand (when the heart pumps blood) & recoil

connective tissue (type)

Cartilage Hyaline

Characteristics:

 ECM = ground substance & fine collagen fibers blend smoothly (glassy appearance); lacks blood vessels, nerves & lymphatic vessels

 Chondrocytes = in lacunae (small cavities), often in small clusters of 2-4 cells (sometimes up to 8)

Locations & Functions:

 Reduces friction & allows for easy movement (joints [covers ends of bones])

 Provides structural support (shapes nose; holds open larynx, trachea, bronchi

connective tissue (type)

Fibrocartilage

Characteristics:

 ECM = lots of parallel collagen fibers in thick bundles, very little ground substance

 Rows of un-clustered chondrocytes in lacunae between collagen fibers

Locations & Functions:

 Provides support & cushioning (e.g., intervertebral discs, menisci), resists pulling & shearing forces (e.g., joints, intervertebral discs, menisci, tendons, ligaments), provides firm attachment point for tendons & ligaments (where they attach to bone), connects/bridges structures (pubic symphysis)

connective tissue (type)

Cartilage Elastic

Characteristics:

 ECM = has similar proportion of ground substance relative to hyaline cartilage, lots of elastic fibers (very fine, thin), some collagen fibers

 Chondrocytes in lacunae

Locations & Function:

 Provides rigidity but w/ more flexibility than other cartilage types (e.g., external ear, epiglottis)

connective tissue (type)

Bone

Characteristics:

 Lots of osteons = in compact bone (hard, dense outer layer of bones); densely packed, cork-like circles w/ concentric rings (lamellae) around a central canal (contains blood vessels, lymphatic vessels & nerves)

 Tiny, dark dots in rings are bone cells (osteocytes); connected by canalicular network

Functions:

 Provide significant strength & rigidity

 Transportation of nutrients & waste via canaliculi

 Remodeling

connective tissue (type)

Blood Tissue

Characteristics:

 Lots of RBCs (small, biconcave discs)

 Some WBCs (fight pathogens) & platelets (blood clotting)

 ECM = plasma (blood cells are suspended in…)

Location & Functions :

 Arteries, Veins, Capillaries

 Transportation (oxygen, nutrients, waste products)

 Protection = WBCs & platelets

 Regulation = of body temp. (distributes heat throughout the body)

JESUS

IS KING