Lect 2: Connective and Specialized Tissue

What are the 3 basic elements thhat compose connective tissue?

cells, fibers, and ground substance

What are the fibers and ground substance of connective tissue collectively referred to?

fibers + ground substance = ECM (extra cellular matrix)

*cells = suspended in the ECM

What is collagen? (Basic)

long strands of protein for tensile strength and flexibility

(connective tissue fiber)

3 main types: I, II, III (but 28+ have been identified)

Where is type I collagen found?

(type I = most common)

tendon, ligament, muscle, bone

Where is type II collagen found?

articular cartilage

Where is type III collagen found?

pliable tissue: blood vessels, wounds

What are reticular fibers?

(connective tissue fibers)

thin branching proteins made of specific Type III collaen fibers

What do reticular fibers do?

act as a supportin net in soft tissues / organs

What are elastic fibers?

(connective tissue)

wavy bundle of elastain (protein) that tolerate stretch

What do elastic fibers do?

allow for tissue to return to origional shape after stretch

What are 8 types of specialized tissues?

nerves, bones, muscles, tendons,ligaments, synovium, cartilage, fascia

Motor vs Sensory electrical Path through body (in laymans terms)

sensory input (body > brain)

motor output (brain > body)

What are the parts/functions of a neuron? (ABC)

A) dendrites: input

B) cell body (Soma): processing, organelles

C) Axon: output

What is the structure of a spinal nerve?

bundles of nerves, blood vessels and connective tissue entering/exiting the spinal cord

How would you describe the parts/purpose of the spinal nervse as they enter/exit the spinal cord?

What is the (simplified) neural pathway?

sensory input > info processed at the level of the spinal cord and brain

> CNS direct body to move

What is osseous tissue?

bone tissue

What are 4 purposes of bone?

store calcium / phosphate

form blood cells

protect vital organs

mechanical basis for movement

What is osseous tissue composed of?

collaen and mineral deposits

What bone claassification are the humerus and femur examples of?

long / tubular

What bone claassification are the carpals / tarsals examples of?

short / cuboidal

What bone claassification are the bones of the cranial vault examples of?

flat (= protective in function)

What bone claassification are the face bone and vertebrae examples of?

irregular

What bone claassification is the patella an example of?

sesamoid (prevent tendons from wearing)

‘looks like sesame seed’

What are the 5 bone form (shape) classifications?

1. long/tubular

2. short/cuboidal

3. flat

4. irregular

5. sesamoid

Is blood supply important to bones?

YES, need rich arterial supply

no blood = avascular necrosis

What factor regarding blood effects fracture repair in elderly populations?

decreased circulation = inc in healing time

What are the 4 stages of bone healing?

1. inflammation

2. soft callus formation

3. hard callus formation (reabsorbed in remodeling stage)

4. remodeling

What is the range immobiliization time related to bone healing?

3 weeks for smaller bones to

8+ weeks for long bones

Wolff’s Law

describes bone remodeling (and tissue remodeling)

growing bone adapts to the forces placed on it

abscence of normal stress > deformity / injury

About what percent of body weight is from skeletal muscle?

40%

3 types of muscle

smooth

cardiac

skeletal

What are 3 things muscles are constantly (unconsciously) working to do?

pump blood

move food through intestines

maintain posture

What are 4 places you can find smooth muscle?

• Hair follicles- responsible for making hair stand on end

• Pupil of eye- dilates and contracts pupil

• Blood vessels and bronchioles

• Urinary bladder

What are the key functional attributes of smooth muscle?

= visceral muscle

• peristalsis

• emesis (reverse peristalsis)

What are the key attributes of cardiac muscle?

involuntary

muscle fibers special characteristics to facilitate synchronized beating

connection between muscle fiber allow quick electric wave passing

What are the key attributes of skeletal muscle?

voluntary (or reflex- without conscious control)

What connects mucle to bone? what part of the bone does it attach to?

Sharpey’s fibers of tendon connect muscle to the periosteum of bone

How are skeletal muscle fibers arranged?

fibers > bundles (fascicles)

What are different bundle configurations of skeletal muscles?

• parallel

• fusiform

• unipennate

• bipennate

• multipennate

• convergent

What are the main attributes of Type I skeletal muscles?

• slow twitch

• “red” fibers

• slow

• endurance

• postural

What are the main attributes of Type II skeletal muscles?

• fast twitch

• “white” fibers

• anaerobic activity

• bursts

Motor unit

a neuron + all the muscle fibers it innervates

(mult neurons used to innervate all the fibers inn one muscle)

*neuron activates ALL fibers in amotor unit

Motor endplates

in muscle fibers where neurons terminate

How does the number of motor units in muscles used for more refined movements change?

more motor units = more precise control

Describe the muscle contraction: concentric

muscle shortens

force of muscle > greater than > opposing force

‘concentrating pose bring arm to forehead’ ‘cheers’

Describe the muscle contraction: Eccentric

muscle lengthens

opposing force becomes greater than muscle force

*can be involuntary! (until- failure) or voluntary!

Describe the muscle contraction: Isometric

no length change

muscle contract but stationary

‘pushing a metric ton’

“gripping cup just enough that it doesn’t slide out of your hand”

is an example of what type of muscle contraction?

isometric

What are tendons?

attach muscle to bone (ligaments = like, so t is the opposite)

• tough, cable-like fibrous tissue

• flexible to bend / shock absorb

• can be vascular depending on if its surrounded by blood vessels or tendinous sheath

What are ligaments?

connect bone to bone (Ligaments connect Like)

• enhance joint stability

• guide joint motion

• *provides proprioceptice feedback (contains mechanoreceptors and free nerve endings)

• can initiate protective reflexes

What joint connector can provide proprioceptive feedback?

Ligaments

contain mechanoreceptors + free nerve endings

Cartilages

What is fascia?

• thin membrane of connective tissue

• covers structures of the body

• protect / bind to structural units

• seperate dif body regions / systems

• sheathes nerves / blood vessels

• continuous matric around all body structures

What are some limitations of connective tissue?

variety of limits bc variety of connective tissue types

many patients in OTs have 1+ limits impacting their function

(is it in video portion of lecture?)