ANAT Ch 4 Tissues BULK PT 2

BULK of info from textbook [starting from Connective Tissue Proper]

what’s present in all connective tissue proper

fibroblasts

fixed cells examples and meaning

fibrocytes, adipocytes, mesenchymal cells

they remain within the connective tissue

what other cells do if not fixed cells

move in and out of connective tissue in response to chemical signals

examples things found in connective tissue proper but are actually part of immune system protecting the body

macrophages

mast cells

lymphocytes

plasma cells

phagocytic cells

the most abundant cell in connective tissue proper

the fibroblast

how does fibroblast contribute to matrix

polysaccs and proteins secreted by fibroblasts combine w extra cell fluids > produce viscous ground substance which + embedded fibrous proteins = extracellular matrix

fibrocyte

less active form of fibroblast

second most common cell type in connective tissue proper

adipocytes

cells store lipids as droplets that fill most of cytoplasm

2 basic types: white and brown

brown adipocytes

store lipids as many droplets

high metabolic activity

white fat adipocytes

store lipids as single large drop

metabolically less active

number and type of adipocytes depends on

tissue and location

varies among individuals in the population

mesenchymal cell is a multipotent adult stem cell meaning

cells can differentiate into any type of connective tissue cells needed for repair and healing damaged tissue

macrophage cell

large cell derived from monocyte (type of blood cell)

enters connect tissue matrix from blood vessels

when stimulated, macrophages release

cytokines - small proteins act as chemical messengers

what do cytokines do brief

recruit other cells of immune system to infected sites + stimulate their activities

how macrophages moving

roaming/free - move rapidly by amoeboid movement

engulf infectious agents and cellular debris

fixed macrophages

permanent residents of their tissues

mast cell

found in connect tissue proper

has many cytoplasmic granules

what do mast cell granules contain

chemical signals: histamine, heparin

explain allergic response

when mast cells irritated/damaged > release histamine (inflammatory mediator) > vasodilation, increase blood flow to injury/infection + itching, swelling, red

like blood cells, mast cells are derived from

hematopoietic stem cells

part of immune system

3 main types fibers secreted by fibroblasts

collagen fibers

elastic fibers

reticular fibers

collagen fibers made from

fibrous protein subunits linked tgt form long and straight fiber

characteristics of collagen fibers

flexible, great tensile strength, resists stretch

ligaments and tendons: resilience, strength

hold connect tissue tgt even during movement

elastic fiber contains

protein elastin + lesser amounts other proteins, glycoproteins

main property of elastin

after stretch/compress > will return to original shape

elastic fibers prominent in

elastic tissues in skin

elastic ligaments of vertebral column

reticular fiber also formed from

same protein subunits as collagen fibers but

fibers remain narrow, arrayed in branching network

reticular fibers found

throughout body but most abundant in reticular tissue of soft organs (liver, spleen) where anchor + structure support parenchyma

parenchyma

the functional cells, blood vessels, nerves of the organ

proteoglycan

ground substance (hyaluronic acid, proteins)

protein core and polysacc branches

attracts + traps moisture forming clear, viscous, colorless matrix (ground substance)

where loose connective tissue found

btwn many organs where both absorbs shock + binds tissues tgt

loose connective tissue allows

water, salts, various nutrients diffuse through to adjacent/imbedded cells + tissues

adipose tissue consists mostly of

fat storage cells, with little extracell matrix

lots of capillaries allows rapid storage/mobilization of lipid molecs

what adipose tissue most abundant

white

why can white adipose tissue appear yellow

carotene and related pigments from plant food

white fat contributes mostly to

lipid storage

serve as insulation from cold + mechanical injuries

where in body examples where white adipose tissue found

kidneys

cushioning back of eye

who brown adipose tissue more common in

infants aka baby fat

where brown adipose tissue in adults

neck and clavicular regions of body

how brown adipose tissue efficient at metabolizing stored fat

many mitochondria in cytoplasm

wdym brown adipose tissue thermogenic

as it breaks down fats, it releases metabolic heat rather than producing ATP

areolar tissue shows ____ specialization

little

areolar tissue contains what and how distributed

all cell types and fibers prev mention

distr in random, web like fashion

where find areolar tissue

fills space btwn muscle fibers

surrounds lymph/blood vessels

supports organs in abdom cavity

underlies most epithelia

reticular tissue

mesh-like, supportive framework for soft organs

ex: lymphatic tissue, spleen, liver

reticular cells produce

reticular fibers that form network onto which other cells attach

dense connective tissue contains more

collagen fibers than loose connect tissue

= displays more resist to stretching

2 major categories of dense connect tissue

regular

irregular

dense regular connect tissue fibers are parallel to e/o >

enhances tensile strength and resistance to stretch in direction of fiber orientations

ligaments and tendons are made of

dense regular connect tissue

*in ligs not all fibers parallel

dense regular elastic tissue

has elastin fibers + collagen fibers = allows return after stretch

elastic ligaments examples

in vocal folds

between vertebrae in vertebral column

dense irregular connective tissue, direction of fibers is random >

gives tissue more strength in all directions, less strength in one particular direction

dense irregular connect tissue arrangement of fibers

some crisscross > mesh

others alternating layers, 1 layer same direction, layers stacked at angle

examples dense irregular connective tissue rich in collagen fibers

dermis of the skin

examples where dense irregular elastic tissues give strength + ability return og shape

arterial walls

disorders of the connective tissue:

tendinitis

older adults at risk for tendinitis bc

elasticity of tendon tissue decreases w age

2 major forms of supportive connective tissue and they allow

cartilage and bone

allow body maintain posture, protect internal organs

distinctive appearance of cartilage is due to

polysaccs called chondroitin sulfates

chondroitin sulfates bind w

ground substance proteins to form proteoglycans

chondrocytes

cartilage cells embedded within cartilage matrix

lacunae / lacuna

space the chondrocytes occupy

perichondrium

layer of dense irregular connective tissue that encapsulates the cartilage

cartilaginous tissue is avascular >

all nutrients need to diffuse through matrix to reach chondrocytes (+slow healing)

3 main types cartilage tissue

hyaline cartilage

fibrocartilage

elastic cartilage

most common type of cartilage in body

hyaline cartilage

hyaline cartilage consists of

short, dispersed collagen fibers

lots of proteoglycans

appears clear and smooth

hyaline cartilage strong and flexible, where found

rib cage, nose

covers bones where meet to form moveable joints

hyaline cartilage makes up a template of

embryonic skeleton before bone formation

a plate of hyaline cartilage at the ends of bone allows

continued growth until adulthood

why is fibrocartilage tough

has thick bundles of collagen fibers dispersed through matrix

examples of fibrocartilage

menisci in knee joint

intervertebral discs

elastic cartilage contains

elastic fibers + collagen + proteoglycans

example in body where elastic cartilage gives rigid support and elasticity

ear lobes, external ear

the hardest connective tissue

bone

bone’s rigid extracell matrix contains

mostly collagen fibers embedded in mineralized ground substance w hydroxyapatite

hydroxyapatite

a form of calcium phosphate

without collagen, bones would

be brittle, shatter easily

without mineral crystals, bones would

flex, provide little support

osteocytes

bone cells like chondrocytes

located w/in lacunae

histology of transverse tissue from long bone shows a

typical arrangement of osteocytes in concentric circles around central canal

is bone a highly vascularized tissue

yes

unlike cartilage, bone tissue can

recover from injuries relatively quick

cancellous bone vs compact bone

cancellous bone:

• sponge under micro, empty space btwn trabeculae (arches of bone proper)

• lighter than compact, found in interior some bones + end of long bones

compact bone:

• solid, more structural strength

two examples fluid connective tissues

blood and lymph

the formed elements circulating in blood are all derived from

hematopoietic stem cells in bone marrow

erythrocytes

aka red blood cells

transport oxygen, some CO₂

leukocytes

aka white blood cells

responsible for defend against potential harm microorgs/molecs

platelets

cell fragments involved in blood clotting

some white blood cells have ability to

cross endothelial layer that lines blood vessels > enter adjacent tissues

nutrients, salts, wastes are dissolved in

the liquid matrix and transported through body

lymph contains

a liquid matrix + white blood cells

lymphatic capillaries are extremely permeable

allows larger molecs and excess fluid from interstitial spaces to enter lymphatic vessels

lymph drains into blood vessels, delivering

molecules to the blood that otherwise can’t enter bloodstream

specialized lymphatic capillaries transport

absorbed fat away from intestine and deliver molecs to blood

skeletal muscle is attached to

bones, its contraction allows locomotion, face express, posture, other voluntary movement

40% of body mass is made of

skeletal muscle

skeletal muscles generate heat as

byproduct of contraction = participates in thermal homeostasis