Lec 2

tissue

similar cells and their associated non-cellular (extracellular) components working together to perform a share function

extracellular matrix (ecm)

provides structural support, defines mechanical properties (strength, elasticity, compression/resistance), and regulates cell behavior through biochemical signaling

epithelial

lines body surfaces, cavities, hollow organs and glands; provides protection, secretion, and absorption.

connective tissue

supporst, binds, and protects other tissue; the most abundant and widely distributed tissue type

what are the types of connective tissue?

bone, cartilage, blood, fat

what are the 4 major tissue types?

epithelial, connective, muscle, nervous

muscle tissue

specialized for CONTRACTION generates forces and drives movement of the body and internal organs

how do muscle cells look like?

they are elongated cells (fibers) containing contractile proteins

nervous tissues (wot they do)

generate and conducts electrical impulses; coordinates communication between body regions and delivers input from external stimuli

where is the nervous tissue?

brain, spinal cord, nerves

where is the epithelial tissue?

lining of the GI tract organs, hollow organs, skin surface (epidermis)

where is the muscle tissue

cardiac muscle, smooth muscle, skeletal muscle

where is the connective tissue

fat and other soft padding tissue, bone, tendon, blood, cartilage

what does connective tissue do

supports, binds, and protect other tissue

what is the major component of connective tissue

extra cellular matrix (ecm)

what are the three types of protein fibers

collagen, reticular, elastic

what is collagen

the most abundant resistant to shearing and tearing

what is reticular connective tissue

delicate and thin, creates a flexable scaffold, can filter fluid

what is elastic connective tissue

rubber like quality aids in stretching and bending

what are the cell types found in connective tissue

fibroblasts, adipocytes, macrophages

fibroblasts

most abundant cell type, produce ECM fibers, and aid in wound healing (make scabs)

adipocytes

fat cells, cushion and insulate

macrophages

remove dead cells and tissue debris, aid in tissue repair, aid in immune response

loose fibrous connective tissue

flexibility , cushioning allows fluid movement, equal distribution of fibers, ground substance, and cells; fibers are random and loosely woven

dense fibrous connective tissue

provides stress resistance and protection; more fibers than ground substance, fewer cells than loose; high fiber density in regular or irregular pattern (ex: dermis, tendon, ligament)

ecamples of supportive connective tissue

cartilage, bone

supportive connective tissue

provides structureal support and mechanical framework

what is cartilage?

smooth surface and shock absorption at the joints

what is bone

ridge support for movement and organ production produces blood cells and stores minerals

what does fluis connective tissue do?

transport nutrients, gasses and immune cells

what are examples of fluid connective tissue?

blood and lymph

what does blood do?

it helps in nutrient and gas exchange, immune defense

what is lymph do?

immune serveillance

what are the musculoskeletal connective tissue types?

fibrous and supportive

what are the fibrous connective tissue types?

tendon, ligament, fascia

what does tendon connect?

muscle to bone

what does a ligament connect?

bone to bone

what does fascia connect?

wraps and support all body structures

what are the types of supportive musculoskeletal connective tissue?

cartilage and bone

what is the cartilage composition

matrix (60 % water and 40% collagen) and cells (chondrocytes)

matrix

it is avascular (obtains nutrients from diffusion) and the water resists compression, but it is vulnerable to twisiting and bending(tearing easily)

types of cartilage

hyaline, fibrocartilage, elastic cartilage

hyaline

type of cartilage that is smooth joint surfaces, supports respiratory tract bone growth in children, and typical compression; it is the most abundant; found on joints, ends of long bones respiratory passages and in fetal skeleton (nose, end of ribs, hips, elbow)

fibrocartilage

is for shock absorption and tensile strength; packed collagen fibers; resists stretch and compression; found in tervertebral discks, knee joints, pelvis(unites bpth sides of pelvis))

elastic cartilage

flexible, dense elastic fibers, maintains shape when bending, stretchy, found in ear, tip of nose, epiglottis

what is bone

it provide rigid support for movement and organ protection, produces blood cells, stores minerals ( it is ridges because of calcium and hydroxyapatite salt)

what cells are embedded in the bone matrix?

osteocytes, osteoblasts, osteoclasts

osteocytes

primary bones cells, mechanical stress sensors +regulating bone remodeling

osteoblasts

make organic bone matrix

osteoclasts

break down bone tissue

types of bones

compact and spongy

compact bones:

strength of weight bearing, rigidity for muscle attachment (hard dense outer layer)

spongy (trabecular or cancellous) bones

meshwork of rigid bone surrounding bloods vessels and marrow tissue, high vascularized

gross anatomy of bone

periosteum, articular cartilage, medullary cavity, red bone marrow, diaphysis, epiphysis

periosteum

fibrous connective tissue encasing bone, active in growth, nourishment, and repair

articular cartilage

hyaline cartilage lining the ends of bone

medullary cavity

contains yellow bone marrow (fat and stem cells)

red bone marrow

tissue that produces blood cells (red and white) and platelets

diaphysis

shaft of long bones

epiphysis

rounded ends of longbones

what is bone fracture

break in bone due to truma or pathology; many types depending on force and direction of force

types of fractures

complete, incomplete, oblique (angled), transverse

what are the healing stages of a fracture?

hematoma formation, fibrocartilaginous callus formation, bony callus formation, and bone remodeling

what is hematoma formation?

blood clot forms, immune cells cause inflammation and debris clearance) (last 1wk)

fibrocartilaginous callus formation

fibroblasts and chondroblasts form fibrocartilage, new blood vessels provide nutrients (lasts for 2-3 wks), 1st physical bridge

bony callus formation

osteoblasts produce new bone matrix and replace cartilage (lasts for 3-6wk)(why you wear a cast for 6 wks)

bone remodeling

osteoclasts and osteoblasts together reshape bone, immature woven bone organized lamellae (takes months to years)

what is the key to starting healing?

periosteum is needed to start healing (if damaged healing is impared)

what is part of the axial bones?

skull, vertebral column, sternum & ribs

what is part of the appendicular bones?

pectoral girdle, pelvic girdle, upper limbs, lower limbs

what is part of the pectoral girdle?

clavicle & scapula

what is part of the pelivic girdle?

pubis, ilium & ischium fused to form hip bone or os coxae

what is part of the upper limbs?

humerus, radius & ulna, carpals, metacarpals, phalanges

what is part of the lower limbs?

femur, tibia& fibula, tarsals, metatarsals, phalanges

what are the long bones

tubular, found in appendages (femur, humerus)

what are the short bones

cuboidal, found primarily in wrist and ankle

what are the flat/squamous bones?

thin plates found in the axial skeleton (skull, sternum)

what are the irregular bones?

vertebrae and sacrum

what are the seasmoid bones?

develop in tendons where tendons cross long bones (patella)

Endochondral ossification

bones form within feta hyaline cartilage and slowly ossifies; bone forms around soft tissue, supporting these structures

Bone development after 1st trimester

blood vessels invade bringing osteoblasts that deposit bone in diaphysis

Bone development after Childhood

ossification begins in epiphyses

Bone development in Adolescence

epiphyseal plates fuse with diaphysis, end of bone growth

what is the epiphyseal plate?

a thin layer of hyaline cartilage located near the ends of long bones in children and adolescents

where does growth hormone act in the body?

growth hormone acts in the cells of cartilage NOT bone

what are the fibrous joints

sutures, gomphosis, syndesmosis

sutures:

fibrous connective tissue joins two bones of the skull

gomphosis

fibrious connective tissue joins bones like a peg and socket (tooth in socket) (aka synathroses=immovable)

syndesmosis

two bones are joined by a wide sheet of connective tissue (amphiathrosis= slightly movable)

what are the type of cartilaginous joints?

synchondrosis, symphysis

synchondrosis

hyaline cartilage directly connects two bones (synathroses =immovable)

symphysis

pad of fibrocartilage connects two bones (amphiarthroses = slightly movable)

What are the parts in a synovial joint?

articular surfaces, joint capsule, joint cavity, synovial fluid, ligaments

articular surface

bone ends covered by hyaline (articular cartilage)

joint capsule

outer fibrous layer + inner synovial membrane

joint cavity

potential space enclosed by capsule

synovial fluid

fills joint cavity; lubricates articular surfaces

ligaments

reinforce joint capsule; connect bone to bone