types of tissues

epithelia characteristics

cells packed close + little ECM

cells lie on basement membrane

covers exterior body surface, line cavities/tubes/ducts/glands

avascular

simple epithelia

one cell layer thick

stratified epithelia

two / + cell layers thick

squamous

short + fat

w>H

cuboidal

w=d=h

cube like

columnar

H>W

tall + thin

endothelium

lining of vascular system

simple squamous

mesothelium

lines walls + covers contents of cavities

simple squamous

connective tissue characteristics

cells are separated

large ECM

ECM made of fibers + ground substance (made from CT cells)

type of CT determined by types of cells present, fibers, + comp. of ECM

CT functions

supportive framework + filler

transport of nutrients + waste

storage of adipocytes

immunity + inflammation substrate

tissue repair basis

fibroblasts

most numerous cell of CT

actively synth. + secrete proteins + carbs that make up fibers + ground sub. of ECM

chondrocytes

cells in cartilage

osteoblasts

make bone matrix

adipocytes

in many CT

most numerous in adipose tiss.

synth + storage of lipids

mesenchymal cells

no role until needed

extracellular fibers (CT)

collagen + elastic

collagen fibers

most common protein in body

structural stability in body parts

synth. by fibroblasts (general), osteocytes (bone), + chondrocytes (cartilage)

laid in direction of stresses on tissue

flexible + HIGH tensile strength, little elastic recoil

elastic fibers

less common

made of elastic + surrounded by microfibrils

formed by fibroblasts + smooth muscle cells

low tensile strength + high elastic recoil

ground substance composition

water

glycoproteins

proteoglycans

ground substance in CT

ground sub. is viscous gel w/ 60-70% water bound to proteoglycans or glycoproteins

proteoglycans

large complex macromolecules

has core protein (glycosaminoglycans (GAGs))

strongly bind to water

glycoproteins

attach components of ground sub to each other

cell recognition, adhesion, migration + proliferation

types of CT

loose (areolar)

desne reg.

dense irreg.

bone

cartilage

adipose

loose CT

loosely arranged fibers w/ lots of GS

btw organs, skin, nerves, + vessels

allows movement + packaging material

site of inflammatory/immune response

dense regular CT

regularly oriented fibers

resist tensile forces applied IN direction of fibers

tendons, aponeuroses, ligaments, deep fascia + intermuscular septa

dense irregular CT

fibers oriented in MANY directions

dermis, joint capsules, nerve/muscle sheaths, deep fascia, perichondrium + periosteum

adipose tissue

beneath dermis

combines w/ loose CT to form superficial fascia

fat pads in synovial membranes of joints

types of cartilage

hyaline

elastic

fibrocartilage

chondrocytes overview

embedded in fiber matrix + ground sub.

lie in lacunae in matrix + nourished by diffusion

hyaline cartilage

inc. load distribution + provide smooth wear-resistant surface

covers bone ends in most joints

costal cartilage of ribs, struct. framework of larynx, trachea, bronchi

forms nasal septum, fetal skeleton, + growth plates

elastic cartilage

normal components of hyaline cart. matrix + elastic fibers

auditory tube, epiglottis, corniculate/cuneiform of larynx, auricle of ext. ear

fibrocartilage

combo. of dense REG CT + hyaline

has added bundles of collage fibers (I) to inc. tensile strength

resistant to compression + force

at insertion sites of tendon/ligaments

intervertebral discs, symphysis pubis, articular discs/menisci, glenoid + acetabular labra, articular cartilage of joints

bone structure

60-70% mineral (inorganic)

20-30% cells + ECM (organic)

5-8% water

ECM of bone matrix

mineralized ground sub w/ collagen fibers

hydroxyapatite crystals

a lot in mineral component of bone

laid down parallel to collagen fibers

gives bone rigidity + hardness

collagen fibers in bone

laid down in ordered parallel sheets (lamellae) along stress lines of bone (Wolffs law)

osteoprogenitor cells

mesenchymal stem cells that differentiate into osteoblasts

types of bone tissue

compact

trabecular

woven

compact bone

vertically running osteons

resist bending/twisting forces

wall of shaft of long bones

trabecular/spongy bone

ends of long bones

interconnecting bars/plates that fill bone ends

resists compressive F at bone ends

arranged along direction of forces placed on bone (Wolff’s law)

woven bone

immature

no uniform orientation of collagen fibers

in tumers, fractures, newborns

periosteum

outer surface of bone covered by this (NOT at articular surfaces)

dense fibrous CT

has arteries, veins, lymphatics + sensory nerves

anchored to bone by collagen fiber bundles

blood supply of bone sources

nutrient artery

arterial plexuses around joint

capillaries from muscles

nutrient artery supplies

medullary cavity + endosteal surface

arterial plexuses supplies

epiphyseal + metaphyseal regions around the joint

capillaries from muscles supplies

periosteal region

bone remodeling

throughout life + adapts to mechanical demands placed on it (Wolff’s law)

remodeling in trabecular > compact

bone resorption followed by formation (TIGHTLY COUPLED)

dec. loads = dec. muscle mass

muscle cells characteristics

surrounded by small ECM (in form of basement membrane)

large amounts of contractile proteins (actin/myosin) in cytoplasm

elongated + oriented w/ long axes in same direction

classification of muscles

striated (skeletal, cardiac)

non-striated (smooth)

smooth muscle

spindle-shaped

single central nucleus

cytoplasm filled w/ myosin filaments surrounded by actin filaments

slow, prolonged contraction

separated by CT

skeletal muscle

muscle fibers (long, multinucleated cells)

sarcolemma: plasma membrane

sarcoplasm: cytoplasm

sarcoplasm filled w/ myofibrils → composed of myofilaments of A + M

myofibril extends length of muscle fiber

muscle parts (large to small)

muscle → fascicle → muscle fiber → myofibril → myofilament (A + M)

skeletal muscle CT sheaths

epimysium

perimysium

endomysium

all fuse at myotendial junction to form fibrous bundles of tendons

epimysium

tough dense sheath that surrounds entire muscle

perimysium

thick sheath

groups invid muscle fibers into fascicles (bundles)

endomysium

delicate

surrounds indiv muscle fibers

small nerve fibers + capillaries here

neuromuscular bundle

nerve (sensory + motor) + blood supply that enters muscle together

travels in CT sheaths

individual muscle fibers innervated by

single myelinated motor fiber that ends on sarcolemma at neuromuscular junction/motor end plate

cardiac muscle

cells attached to each other at intercalated discs

nervous tissue composed of

cells + processes

neurons + neuroglia

separated by small EC space

neurons/nerve cells

excitable + specialized for reception, integration, condition + transmission of info

neuron has cell body w/ narrow processes

cell body has cytoplasm (holds organelles)

neurons classified (unipolar, bi, multi)

multipolar neurons

has dendrites and axons

axon branches to form synaptic endings or effector endings

neuroglia/supporting cells

non-excitable

smaller + more numerous than neurons

form/maintain myelin sheaths around axons

structural/metabolic support to neurons