Studied by 12 peopleWhat is the skeleton
The framework of the body, including bones, cartilage, dense connective tissue and joints
name the functions of the skeleton
provide framework, protection, store minerals and fats, produce blood cells and allow movement of the body
what is the axial skeleton
bones surrounding the central axis, including the cranium, mandible, facial bones, vertebral column, rib cage and sternum
what bones make up the vertebral column
7 cervical, 12 thoracic, 5 lumbar, 5 sacarl and 4 caudal
what is the appendicular skeleton
the upper limbs, shoulder girdle, lower limbs and pelvic girdle
bones include humerus, ulna, radius, carpals, matacarpals, phalanges, clavicle, scapula, ilium, ischium, pubis, femur, fibula, tibia, tarsals, metatarsals
describe the diaphysis
long cylindrical shaft in middle of bone
hollow
compact bone walls
describe the medullary cavity
the space within the diaphysis
contains yellow bone marrow in adults and red bone marrow in kids
lined with endosteum
what is the periosteum
a tough fibrous membrane covering the outside of the diaphysis and other non articulating parts of the bone
what are the epiphyses
the wide bine ends covered in hyaline (articular cartilage)
their centres are filled with spongy bone and red bone marrow
enclosed by thin compact bone
what are the names of the 2 epiphyses
distal epiphysis (furthest from body)
proximal epiphysis (nearest to body)
what tissue type are bones
connective tissue because they are composed of a large matrix and few embedded cells
what is the rigid bone matrix made of
mineral salt deposits (calcium and phosphate ions)
and collagen fibres
what makes up compact bone
osteons which are organised parallel to eachother and the long axis
describe an osteon structure
central canal (haversion canal)
concentric lamellae
lacunae (depressions between lamellae)
what do lacuane contain, and describe these structures
osteocytes which are mature bones cells
they communicate and pass materials by cytoplasmic extensions through cannaliculi (tiny canals)
what do central canals contain
blood vessels which enter through foreamens and then divide so each central canal has 1 arteriole and 1 venuole
what is trabecular bone
spongy bone made of trabeculae (bony plates)
trabeculae are loosely organised, following lines of force
there is red bone marrow and blood vessels in trabecular spaces
spongy bone is porous and strong
what are the 3 bone cell types, with descriptions
osteoblasts → build bones by depositing minerals in matrix (found under periosteum)
osteocytes → mature/maintaining bone cells
osteoclasts → bone destroying cells, for growth and remodelling (found on trabeculae edges and in lacunae between lamellae)
what is cartilage
A connective tissue which provides support and flexibility
Describe cartilage composition
the matrix is made of firm and flexible chondrin (protein carbohydrate complex) and collagen fibres
The cells are called chondrocytes found in cavities in the matrix, which originate from chondroblasts
describe hyaline cartilage
glossy white/blue
Firm and strong
Fine and tightly packed collagen fibres
Chrondrocytes in 3/4 and scattered
Found on epiphyses, nose, ribs, , trachea, bronchi
describe elastic cartilage
fine semi tight collagen fibres and thick elastic fibres
Very flexible and supportive
Found in ear, epiglottis and Eustachian tubes
Describe fibrous cartilage
weight bearing and compressable
Thick parallel collagen fibres
Chondrocytes exist in rows
Found in intervertebral discs, menisci in knees, symphisis pubis
What is a fibrous joint
a joint which allows no movement between the two bones. They are held by fibrous connective tissue and are difficult to break
E.g. In skull, teeth and jaw
What is a cartilaginous joint
joints held bybcartilage, meaning they have slight movement
E.g. Pelvic junction, vertebrae
What is a synovial joint
give maximum movement to bones
There are six types of synovial joints
What is a tendon
A strong felxible tissue joining a muscle to a bone
Fibres are in a parallel arrangement
What is the synovial cavity
the space between articulating bones in a synovial joint
Filled wihr synovial fluid
what is a bursae
sacs of synovial fluid which prevent friction between bone and ligament or tendon
What is the meniscus
in the knee it is a cartilage pad which acts as a shock absorber and divides joint
What is the cruciate ligament
in the knee its a cross shaped ligamen twhihc holds the joint together (connects the two bones)
What is the synovial membrane
membrane which secretes synovial fluid
Made of loose connective tissue and elastic fibres + some fat storing tissue
Describe a ball and socket joint
a spherical bone head fits into a cup like cavity of another bone
E.g. Femur into pelvis
Describe a hinge joint
convex bone fits into concavity of another bone
Movement on one plane only
E.g. Elbow or knee
Describe a pivot joint
a round point or conical end articulates into a ring of bone and ligament
E.g. In 1st and 2nd vertebrae
Describe a gliding joint
two bones rub against one another and provides back and forth or side to side movement
Surrounding ligaments can restrict movement
E.g. In wrist (carpals)
Describe a saddle joint
only true saddle joint is where thumb joins the hand
One bone is convex one way and other bone is convex other way
They can move side to side or back and forth
Describe and ellipsoidal joint
slightly concave bone slips into a slightly convex bone
Can move two ways e.g. Side to side and up and down
E.g. Radius and carpals or metatarsals and phalanges
What is flexion
the angle between the articulating bones descreases
Bones move closer together
together
What is extension
increase the angle between articulating bones
The bones move further apart
What is adduction
limbs move towards the midline of body
What is abduction
limbs move away from midline of body
What is rotation
the movement of a bonebaround its long axis
What is a muscle classified as and why
muscles are organs because they cknsist of two or more tissues i.e. Muscle tissue, connective tissue, tendons, blood vessels, nerves
What are the 4 features of muscle tissue with descriptions
extensibiltiy - lengthen
Contractibility - shorten
Elasticity - return to originl length
Excitability - responds to stimuli i.e. Electrical nerve impulse
what makes up a muscle fibre with descriptions
sarcolemma the plasma membrane
Sarcoplasm the cytoplasm
Sarcoplasmic reticulum the ER surrounding myofibrils
Numerous mitochondria
Many periphery nuclei
Myofibrils the rod like structures running the fibres length
What makes up a myofibril
the two protein myofilmanets myosin (thick) and actin (thin)
Describe the parts of a myofibril
A band - length of myosin (dark band)
I band - length of action only (light band)
H zone - area of myosin only
Z line - where sarcomeres meet
M line - line in middle of A band
List the structural order of a muscle
myofilament, sarcomere, myofibril, muscle fibre, muscle fibre bundle, muscle
What does the sliding filament model suggest
It explains how muscles contract by proposing that sarcomeres shorten because actin and myosin myofilaments slide past one another and overlap
What are the 3 connective tissue is a muscle
Epimysium - surrounds entire muscle allowing musclez to contract
Perimysium - sheath covering each fascicle (fibre bundle) separating them
Endomysium - separates individual muscle fibres from one another
Describe in full the sliding filament model
sarcomeres, the contractile unit of muscles, are made of thick myofilaments myosin and thin myofilaments actin
Between sarcomeres are dense areas called Z lines where actin filaments join
Upon nervous stimulation of action potential the actin and myosin slide past each other and overlap
Z lines move closer and sarcomere shortens
All sarcomeres shorten, shortening myofibril length hence shortening whole muscle
During contraction the H zone shortens, or disappears and the I band shortens but myofilament lengths stay the same
What is an antagonistic pair
a pair of muscles which work in opposites to make actions possible
What is the agonsit
The muscle which makes the desired action by contracting
Also known as the prime mover
What is the antagonist
the muscle which relaxes during movement
What are synergists
muscles which assist agonist
if agonsit crosses 2 or more joints, synergists will prevent undesired actions
What is the origin of a muscle
where it connects to the stationary bone
What is the insertion of a muscle
where it connects to the movable bone
What is the muscle belly
The section between tendons of origin and insertion
What is an extensor
a muscle which straightens a limb
what is a flexor
a muscle which bends a limb or joint
Note
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