HAPIA: Joints and muscle

Anatomical joints

the site at whch two bones join togther and are hedl in place

• also the site of articulation which can cahnge depedning on joint type

• can be classifed strcturally or functionally

• joints in the skull are fibrous /sutures and don’t move

Bony joints

Bones are held togther by the fusion of two bones (an epiphyseal line)

• are the reminanats or more obvious joints from younger years

• not very mobile

Fibrous joints

bones that are held togther by dense collagen fibre like the sutures in the skull

• very tight and tsring so not very mibiles

• some may become fribours joints like the ones that connects the bones tht lines the forhead

Cartilaginous joints

bone hedl together by cartilage such as hyalin catilage or fibrocartilage

• Primary: are made with hyaline and are things such as the growth plate

• Secoundary: fribrocartilage joints like between the vertebrea

• more mobile than the other two joints

Synovial joints

held together be a synovial memebrane/casule made of ribres

• provides a wider raneg of motion and is more mobile

• - has supporting featires that increase the stregth and stability of the joint

• shoulder, elbow, hip, kness, ankle, knuclkes

Synarthrotic joints

immobile joints as bony joints

• e.g the pelvic bone which begins as three bone but fuse into 1

Amphiarthrotic joints

alightly mobile joints like cartilagous joints

• e.g in the thoracc cavity for breathing

Diarthrotic joints

very mobile joints such as synovial joints

• some are more mobile than other depdning of other strctural fearures

• -wrist

Jiont stability

is increased by the presenc of other anatomical strctures

• an increase in mobility = decrease in integrity

• can be passive or active featires

Passive features: Bone geometry

the aligment of bien that allows them to fit togther like puzzel peices

• congruency = when bones fit perfectly like puzzel peices and are stable

Passive features: Ligaments

a fibrous band that connect boen to bone at joints and holds them together strongly

• acts like a blank arounf the joint that fusses them togther

• prevenst dislocation and speration of joint

Passive features: Articular cartilage

a smooth frictionless surface found between 2 bones that reduce any friction or grating that occurs in movements

• increase congruency and mobility

• can absorb shock

Passive features: joint capsules

a strong fibrous casing thet holds bines tigther and can support other features

Active features: Muclse

attach to bones via tendons and pull them togther in contrcation to allow for movement

• increase stabilyt and resists sterch

consequnce of destabilsed featires

the destabilseing of featires can increase the risk fo dislocation as the joint becomes unstable

• is very painful

causes of joint impairment

• trauma

• overuse

• genetic factors

• hypermobility

• abnormal geometry

• underlying conditions

Synovial memebrane

a doible lareyed tissue that lines the internal structures at a synovial joint

Internal lining of synovial joints

comprised of Synoviocytes ( mcrophage /firboblast like cells) that create synovila fluid to fill the cavity between the joint

• lunbrictae the joint to prevent friction

• provides nruerunst and removes waste

External lining of synovial joints

comprised of fribroblasta and blood vessel to increase the stcrtural integrity of the memebrane and anchor the firbours joint capsule

• also proveds blood supply to the internal layer for nutients and waste removal

Support features: fibrous joint capsule

from tects the synovial memebrane by covering it externally

• aka the synovisl joint caspule

• fused to the bone

Support features: External ligamanets + tendons

used to increase the sterngth and stability of the joint

• tendons: hold bone to muscle

• ligaments: hold bone to bone

Support features: Joint cavity

a fluid filled cvity betwee the two bones that is secreted by the synovial membrane

• allows the joint to move around more and increase mobility by providing it space to do so

• fluid is resposible for nourishing the cartilage on teh bone

Support features: articular cartilage

abosrbs any shock that the bones overcome aand allows for the smooth movement of bine against one another

why is the joint cavoty often empty

bauces not stutures are able to exist in their withotu compromising stability

• will still contain fluid

• kness do contain an extra featurtes making them a complex synovial joint

Support features: menisci

a fibrocatilage wedge shaped pad that allows bone with low congruency to fit togther

• provides stability to lower the cahnce of dislocation due to the presence of a ligmanet between and joint like in the knee

Support features: Intracapsular ligament

a ligmanet between to bones inside the synovial cavity used to reinforce it and stabilise

• bones will then cahnge shape to acomadate so the menosci needs o be used

Synovial joint types: Ball and Socket

a round ball shaped bone that fits into a deep cup shape socket

• multi axila joint as they have a very wide range of motion and possible movmnet type

• flexion, extention, abduction, adduction and rotation

Synovial joint types: Hinge

a horizontal cliniders that fits into a wide lego hand like shape

• Uni-axial movement so it can only move one way

• felxion and extension ( elbow)

Synovial joint types: Pivot

a rounded disk that firs into a another rounded disk with a dip in the middlke

• uniaxial movement ( rotation)

• Neck and forearm

Synovial joint types: saddle

both bone are concave but in differnt dirrectly allowing then to like if you were to cup your hand togther with palns facing ecahother

• biaxial ( can move two differnt ways

• flexxion and extesnion + abduction and adduction

• thumb and collar bone

Synovial joint types: Condylar joint

also kninw are ellipsoid are shallow bone and socket joints

• bi axila ( same as saddel)

• knuckles and wrist

Synovial joint types: Planar

two flat surfaces in cntcat that have no distint movements and are not axial

• corprals and tarsal

• - are able to move and glide over on another to fit the shape of whatever they are pressed gaianst

How does our muslce move bones

our skeleton can’t move so muscle will snachor to one bone that it isn’t move and then cross and joint to the bone it is moving and then contrcat to pull them togther

• mucle corntraction = the shortening of muscle that moves the inserted bone at its joint

Origin vs insertion of muscle

Origin: where the muscle is anchored to and where the muscle pulls the bone towrads ( superori aspect)

Insertion: the attachment site of where the bone is pulled by the muslce (inferior aspect)

how does position of muslce effect bone movement

can effect its range of motion

• if on anetrior it will be pulled to the front in flexion

• if on posterior it will be pulled to the back in extension

Flexion vs extension

flexion: the moving of a bone up or towards the body

Extension: the moveing of the bone down or awa from the body /to the posterior

• hand can be hypetmobile so can move further past normal

Abduction vs adduction

abduction: the movement of a bone left /right or away from the body so it is more lateral

adduction the movement of the bone light or right/ towards the body so it is more medial

Circumdention

also knwn as rotaion is the movement of the joint in a circular motion

• rquires the movment of latos of muscles

lateral vs medial

occurs in ball and soacket joints as the

• Lateral: movement away fromthe body but across a horizontal plane at middle joit of a limb

• medial: the same but moves it back towards the body

Proaction vs Supination

Proaction: turing your wrist so that the back or your hand is facing up

Supination: truning your wrist so that you palm is facing up

what are the three types of muscle

• skeletal muslce: controlled voluntarily by the somatic motor division and found attached dirrectly to the skeleton

• Cardiac muscle: contrlled involutary\ily by the Autonomic dividion and found in the myocardium of the haert

• Smooth muscle : controlled involutarily by the Autonomic division and found in organs and vessels

Skeletal muscle function: movement

skeletal muslce crosses over joint to attach to bones and contrcats to pull them towarsd the bon they are acnchored to

• can only move bone in one dirrection according to its potiiton on the body

• can also move the eyes and tongue

Skeletal muscle function: Stbailoity/ prostre

is under contant tension to continually keep our body aligned at the joints and to keep our body upright and balanced

• maintains bodily strtcure

• makes small contrcats + relaxation ot adjust posture

• nerves in the joints and mucles help teel the brain where the body is so balance can be maintained

Skeletal muscle function: respiration

contrcation and relaxtion of te musxes in the toracic cavity allows the lungs to inflate and relax to facilitate breathing

• in the ribs and dispragm

Skeletal muscle function: heat generation

spasms of muslce contrcation used to create shivering that keeps uor body warm suign the heat generated from firction

Skeletal muscle function: Organ proctect + nourishment

Organ proctection: forms string sheild around rogans toprotcet aginst physcial damge

Nourishment: stores carbohydrates and amino acids that can be brokwn down out of muscle in desperate times

• leads to muslce atrophy

Skeletal muscle function: voluntary sphincter control

the control of the external sphincter muscle in the anal and urtheral regions

• the ones cntrolled involuntarily are done by smooth msucle

Skeletal muscle features: Cell size/shape

Long muscle that will space the entire length of the muscle from anchor to insertion and cross over joints

• ensures synchronised contrcation

Skeletal muscle features: Nucleation

contains multiple nuclei due to its large size and the embryotic fusion of 100s of 1000s of myoblasts

• foun nera the edge of the cell

• ensure that sufficnet proteins are made to asisit in contrcation and other functions

• increases the dleiver despite size

• unfused celles sit on the outside of the cell as a stem cell

Skeletal muscle features: contrcatile fetures

contains horizontal lines of actin and myosin filaments that glide over one anoher to allow the muslc eto ‘shorten’ when contrcating

Cardiac muscle function + location

muscle tissue found in the myocardium of the heart

• Pumps blood by contrcating and decreasig=ng the volume of various chmabers to pushe blood out using pressure differences then relaxes to pull blood in

• is the primary build block for the heart that proveds shaoe and strcture ( can gorw when placed under stress be can not be repaired as t has no stem cells)

cardiac muscle: size/shape

small cells that branch out and connect via their projections to other meucle cells

• connect via the intercalated disc which contains desmosomes for binding and gap junctiosn for communication

cardiac muscle: nucleation

contains 1 centrally located nuclei due its smaller size

cardiac muscle: Contractile featires

also contains actin and mysosin fliaments in the same pattern

• slide over one another to get smaller

Smooth muscle function: organ function

used in the contrcation and relaxatio of muscle tissue in organs that facilitates functions by cahnging organ volume

• stomache, intestines, lunges, vessel, bladder, kidneys, reproduction organs

• often done to move inetranl materials

Smooth muscle function: BP

used to mainatins blood pressure in vessel by contrcating a relaxing to redce or increase the resistance that blood hav=s to overscome to move through the body

• in/decrease lumaen diameter

Smooth muscle function: vision and respiration

Vision: regulates the diameter of the pupil to allows in less or more light deodning on the brightness

• can focus the elnse to redrect light

Respiration: regulates the size and diatemer of airways in increase and decrease airflow when necessary

• affected by asthma

Smooth muscle function: hair

arreactor pili muslce under the skin are usedto maintain body temo by contrcating when cold to pull the hairs up and trap heat on the surface of the skin

• creates goose bumps

Smooth muscle function: Involuntary sphicter control

contrans sphicters in the oesophagus, stomach, intestones, gllbladder and pancrease to regulate the releasing if their contents

• controls all other sphincter except the ones by the skeltal muscle

smooth msucke size/shape

smal squamous-like cells that can be indivudual or part of a contractile group

• when goured used for cohension or smoothe muscle contrcations

smooth mucles Nucleotion

1 centrally located nuclei

smooth muscle contractile features

does not have actine and myson and instead appears as a net surronding tissue that cntract and relexes

• ararnaged hapharzardly around cells and allows them to twsit in cntrcation

Skeletal muscle organisation

complex highly organised tissue tat maximises pace and potional and is organis similarly to nerves

• increases effeicncy or muscle contrcation and the energy required to contrcat

Tendons

connect the mucle cells to the bone by anchoring it

• made of fibrous CT and fuses with the mucle cell

• - when mucle contrcats it pulls on tendon which ten pulls on bone

Deep fisia

Dense irregular CT that surrounds muscle tsissue that is neded to lift heavier bone

• covres muslce, nerves and vessels

• suuports and protcets internal strctires and reduced friction

Epimysium

The outer layer of skeletal muscle is made from dense specialised Fibrous CT layers

• reduces friction during contrcation

• fcovers the entire outer surface

perimysium

a middle layer of CT that surrdonds the fasicle and makes up the meaty innards of themucles tissues

• allows for the synchronised movement of muscule cells

fascile

Bunches of muscle cells suroodund be more CT tha are align prarleel to one another

• work togther at the same time

• CT = the endomysium

endomysium

the inner layer of CT found in the fasciles that is dirrectly between each cells

• supports cell stcrture, allows for the transmission of forces and provides neurovasular connection

Muscle cells

myofibrils

Sacromeres

Scarolemma/plasm

what can be found inside the sarcoplasm of skeletal muscle

How does muscle contrcation occur

Areas of the sacromere

Skeletal muscle healing: destruction/ inflammation

Skeletal muscle healing: Regeneration

Skeletal muscle healing: remodeling

Cardiac msucle healing

Carduac msucle healing regenartion

Cardiac msucle healing Scar maintanence

smooth muscle healing

Smooth muscle healing: cell division/ differentiation

smooth msucle healing repair and maintenance