Chapter Eight Flashcards
The musculoskeletal system allows movement
What is the function of the musculoskeletal system
Maintains posture and produces movement which is achieved through a series of skeletal muscles that are able to contract out of will
Muscle tissue content and function
- Highly specialised elongated cells which have elastic properties
- Provides source of power for movement and posture and alters the shape and size of internal organs
How many muscles are in the human body
324
3 types of muscle
- Skeletal
- Smooth
- Cardiac
Function of skeletal muscle
Connects the various parts of the skeleton through one or more connective tissue tendons
What happens to skeletal muscles when they contract
- Shorten and move various parts of the skeleton
- Repeated activation of this muscle can lead to fatigue
How is skeletal muscle activated
Signals carried to the muscles via nerves
Function of smooth muscle
Alters the activity of various body parts to meet the needs of the body at that time
Contractions of smooth muscle
- Slow and uniform
- Fatigue resistant
Where is smooth muscle located
Blood vessels, respiratory tract, inside the eye, and inside the gastro-intestinal tract
Function of cardiac muscle
Provide the contractile activity of the heart
Contractions of cardiac muscle
- Involuntary contractions and extremely fatigue resistant
- Contractile activity can be gradated
The structure of skeletal muscle
Bundles of muscle cells surrounded by tough connective tissue
Components of skeletal muscle
Muscle > Fascicle > Muscle fibre > Myofibril > Actin and myosin filaments
Properties of muscles
- Contractability
- Elasticity
- Extensibility
- Excitability
What happens when a muscle contracts
They shorten and the belly of the muscle increases in diameter
Which muscle is responsible for the movements of the body
Skeletal muscle
How are skeletal muscles attached to the bones
- Attached to both ends
- One end is fixed to the stationary bone and is called the origin
- The other end is attached to the moving bone and is called the insertion
How do skeletal muscles move
In pairs
Agonist (Prime mover)
The muscle or group of muscles that contract to produce a desired effect
Antagonist
The muscle or group of muscles that relaxes to oppose the action of agonist muscles
Synergist
The muscles surrounding the joint being moved
Fixators
The muscle or group of muscles that steady joints closer to the body axis so the desired action can occur
Stabiliser (Fixator muscles)
Muscles that are needed to ensure the stabilisation of other parts of the body or bone during movement
How many directions can a muscle contract
ONE
How is voluntary movement of the body produced
The contraction of muscles (after relaying of an impulse generated in cerebellum)
Sliding filament model
- When a muscle contracts the sarcomeres shorten
- 2 lines are drawn closer together
- ‘A’ band remains the same length as the myosin filaments don’t move
- Fibrils shorten as the microfilaments overlap more
Does the sliding filament model require ATP
Yes
How are skeletal muscles controlled
Messages are sent through motor neurons
Motor neurons
- Cell bodies in brain and spinal cord
- Axons extend to muscle
- At muscles is the ends of axon branches which each go into different muscle fibres
- Each part of muscle fibre receives messages from only one motor neuron
How do muscle fibres contract together
When a nerve impulse carries to the end of an axon it is conducted along all units of the branches so all the connected muscle fibres contract together
Motor unit
A motor neuron and all the muscle fibres stimulated by it
How are motor units precise in movement
They are extremely small
How are motor units strong
They are large
How do motor units work if a muscle contracts for a long period of time
They work in shifts
What is a skeletal framework
Bone and cartilage that provides protection, support and movement
Functions of bones
- Support the body
- Protection of soft body parts
- Movement (due to attached skeletal muscles)
- Storage of minerals and fats
- Blood cell production
Movement of bones
Where the bones meet in such a way that they are able to move relative to each other
Protection by bones
- A number of bones are designed to provide protection for vital organs (skull, spinal cord etc)
- Articulation with other bones helps with movement
Support by bones
Without bones we would have no structure and support and would be a bag of jelly with no shape or movement
Storage by bones
- Stores minerals and fats
- Calcium is stored in the bone and removed when the diet is limited in calcium
Blood cell production in bones
The marrow found within certain bone is also involved in the production of a number of blood cell types
Axial skeleton (S.F)
- Skull, vertebral column, ribs & sternum
- Supports and protects organs of the head, neck and trunk
Appendicular skeleton (S)
- Bones of limbs and bones that anchor them to the axial skeleton
- Arms, Legs and Pelvis
Atricultation
Where joints meet, connect and are formed
How many bones are in the human body
206
What are the two types of bone
- Compact bone
- Spongy bone
Compact bone
A dense form of bone
Spongy bone
- Also called cancellous bone
- Bone that contains large spaces; appears ‘spongy’
Cartilage
Smooth elastic tissue that covers the ends of joints for protection
Where is cartilage found (structurally)
Trachea, nose, outside of ear and bronchi
Function of cartilage
Provides strength, flexibility and cushioning where bones meet on the surface of bones and joints
What is the process of crating new bone called
Ossification
What are osteoblasts
The cells involved in growing new bone
What are osteoclasts
The cells involved in the break done of old bone
Another name for growth plate of a bone
Epiphysial line
Tendons
Fibrous connective tissue which attaches muscle to bone
Ligaments
Fibrous connective tissue that attaches bone to bone
Joints
The site where two or more bones meet
How are joints classified
Through evaluation of their function and structure
Types of joints
- Fibrous
- Cartilaginous
- Synovial
Fibrous joints
- Connective tissue joins bones
- NO movement/immovable
- Found in skull
- Short fibres
Cartilaginous joints
Joints held in place by cartilage which allow slight movement to occur
- Vertebra
Synovial joints
Freely moving, which is limited by the ligaments, muscles, tendons and adjoining bone
What are the 6 types of synovial joints
- Hinge
- Ball and socket
- Gliding
- Saddle
- Condyloid
- Pivot
Hinge joints
- Allows movement on one plane only
- Allows extension and retraction of appendage
- Elbow & knee
Ball and socket joint
- Forms when a spherical head of one bone fits into the cup cavity of another
- Allows for radial movement in almost any direction (360)
- Hips & shoulders
Gliding joints
- Allows for movement in any direction in a side-side/back-forth motion
- Between carpal bones, tarsal bones, scapula, clavicle & sternum
Saddle joints
- Thumb joining the palm of the hand
- The two bones forming the joint are saddle shaped- concave in one direction convex in the opposite
- They fit together in a way that allows side-side & back-forth movements
Condyloid joints
- The oval surface of one joint fits into the depression in another
- Wrist, knuckles, fingers & toes
Pivot joints
- Formed when the rounded end of one bone articulates within a ring which is formed from bone and ligament
- Allows for a rotational movement
Synovial fluid
Prevents friction by lubricating the joint and preventing bones from moving on each other
Articular cartilage
Covers articulating surfaces of the bones forming the joint. The tissue provides a smooth surface for movement
Capsule
- Dense fibrous tissue attached to the periosteum of the articulating bones
- Flexible to allows movement at the joint whereas its strength resists dislocation
- The capsule is also one of the structures that holds two bones together
Osteoporosis
The loss of bone mass/density which leads to more frequent bone fractures
Osteoarthritis
The gradual degeneration of the joints in which cartilage deteriorates
Is osteoarthritis treatable
No. There is no cure, however pain relieving medication, physiotherapy, surgery or joint replacement surgery may help the issue
Is osteoporosis treatable
Yes. Lifestyle changes that increase calcium and vitamin D and medication
What bones does osteoporosis most effect
Ribs, wrist, vertebrae, pelvis and upper arm
How do bone spurs occur
When the cartilage deteriorates and the bone surfaces are no longer protected they begin to wear away which changes the shape of them and causes these spurs
Does obesity have an effect on osteoarthritis or osteoporosis
Osteoporosis
Function of long bones
- Gives strength to act as scaffold to support weight of the body
- Points of attachment for muscles allowing movement
- Protects internal organs
- Bone marrow produces blood cells
- Stores/releases minerals (in bone)
- Stores/releases fats (yellow marrow)
Structure of long bones (external)
- Epiphysis
- Diaphysis
- Epiphysis
- Cartilage
Structure of long bones (internal)
- Spongy bone
- Red marrow
- Medullary cavity (hollow)
- Yellow marrow
- Periosteum
- Compact bone
- Longitudinal section of long bone
Diaphysis
The shaft making up the main portion of the bone
Epiphysis
The enlarged end of the bone, covered with a thin layer or cartilage
Periosteum
The dense white fibrous outer covering of the bone
Structure of compact bone
Osteons or Haversian systems
Osteon structures
- Central canal
- Lamellae
- Lacunae
- Osteocytes
- Canaliculi
- Blood capillaries, nerves and lymph capillaries
Lamellae
Concentric layers of bony matrix surrounding the central canal in an osteon
Lacunae
Small spaces between the lamellae
Osteocyte
A bone cell
Canaliculi
Tiny canals running between the lacunae
Structure of spongy bone
- Irregular, thin, bony plates called trabeculae
- Nerves and blood vessels pass through the irregular spaces in the matrix
Structure of cartliage
- Collagen
- Chondrin
- Chondroblasts
Collagen
A protein that creates fibres
Chondrin
Protein fibres formed with collagen are embedded in a firm matrix of protein- carbohydrate complex this complex is called chondrin
Chondroblasts
Cartilage cells
Three types of cartilage
- Hyaline
- Elastic
- Fibrocartilage
Hyaline cartilage
- Contains closely packed collagenous fibres which are very fine
- They give cartilage strength and flexibility
- Trache, bronchi, cartilage at the end of bones where a joint is formed
Elastic cartilage
- Conspicuous elastic fibres
- Contains similar fibres to hyaline cartilage but not so closely packed
- Provides flexible elastic support
- Springy
- Ear
Fibrocartilage
- Coarse appearance, thick collagenous fibres
- Not as compact as hyaline cartilage and is able to be compressed slightly
- Spinal column discs
Abduction
Movement away from the midline of the body
Adduction
Movement towards the midline of the body
Flexion
- Decreases the angle between the articulating bones
- Bones come closer together
Extension
- Increases the angle between the articulating bones
- Bones move further apart
Rotation
The movement of a bone around its long axis
Meniscus
A cartilaginous disc found in the knee joint; divides into two parts
