Muscularskeletal system Flashcards
What are the 5 bone types
-sesamoid
-long
-short
-flat
-irregular
Function of sesamoid bones
Embedded in tendons
-protect tendons from stress and wear
e.g. patella
Functions of flat bones
-provide protection (shielding) to organs
-provide large areas for muscle attachment
e.g. scapula, sternum
Function of irregular bones
-protect internal organs
-allow for movement
e.g. vertebrae, pelvis
Function of short bone
-provide stability and movement in the wrists and ankles
e.g. carpals, tarsals
Functions of the long bone
-make red blood cells
-store fat and minerals
e.g. humorous, tibia, fibula, radius, phalanges
How does locomotion in the skeleton occur?
Bone tissue forms a system of levers to which voluntary muscles are attached
Functions of the skeleton
-provide internal organs protection
-store/release fats and minerals
-produce red blood cells
-facilitates movement
-support/scaffolding for the body
How is support provided by a skeleton?
Bone tissue forms a supportive frameworks which gives the body shape and rigidity
How does bone relate to homeostasis?
-helps to maintain a constant level of calcium in blood
-stores fats and minerals
How is blood manufactured in the skeletal system?
-in red bone marrow containing stem cells that differentiate into blood cells, later resulting in creation of RBC’s
What is the appendicular skeleton?
Bones making up the limbs
-allows for articulation of the limbs with axial skeleton
What is the axial skeleton?
Encompasses all bones making up the head and torso
-provides support for erect posture
-protects organs of nervous system and thorax
What is the structure of a long bone?
Epiphysis-enlarged ends of the bone covered w/thin articular cartilage layer and compact bone. Spongy bone on inside along with red bone marrow
Diaphysis-shaft making up main area of bone. Compact bone surrounding a cavity (usually filled with blood vessels) which is also known as the yellow bone marrow cavity
Periosteum-dense, fibrous outer covering of bone
articular cartilage
what is ossification?
Bone development
Axial skeleton includes:
Skull:
-cranium
-face
-hyoid
ossicles
Vertebral column
-cervical
-thoracic
-lumbar
-sacrum
-coccyx
Thorax
-sternum
-ribs
Appendicular skeleton includes:
Shoulder girdle:
-clavicle
-scapula
Pelvic girdle:
-coxal bones
Upper limbs:
-humerous
-ulna
-radius
-carpals + metacarpals
-phalanges
Lower limbs:
-femur
-fibula
-tibia
-patella
-tarsals + metatarsals
-phalanges
Function of the compact bone
Blood vessels are found in the bones passage ways which supply nutrients and oxygen.
Functions of bone marrow
-produces WBC’s (for fight infections)
-RBC’s for oxygen transport
-platelets for blood clotting
Function of spongy bone
Allows for greater transfer of blood and nutrients from the site of blood cell formation
How many bones do adults have? What about infants?
206
Axial= 80
Appendicular= 126
Infants
300
Define the musculoskeletal system
A system comprised of all the bones and muscles in the body
What are the types of muscles
Skeletal, smooth, cardiac
What is the function of skeletal muscle? How does movement occur?
-voluntary activity
-enable the body to walk, run and carry out a wide range of movement due to crossing the joints and contracting
-give body form
-aids in maintaining posture
movement at the joints occurs due to contractions of skeletal muscle
What is the function of smooth muscle? how does movement occur?
-involuntary muscle (not under conscious control)
-aid in movement of the internal organs such as the stomach and intestines
muscle contractions surrounding the alimentary canal cause it’s diameter to narrow in order to push contents along
What is the function of cardiac muscle? How does movement occur?
-involuntary muscle
-located in the heart
during contractions the space in the hearts chambers reduces and pushes it’s blood contents into the blood vessels
What is extensibility?
The ability to be stretched out.
What is elasticity?
The ability to return to the original length after being stretched or compressed.
What are the types of tissue?
Connective, epithelial, muscular, and nervous
Function of the epithelial tissue?
Made up of closely joined cells and are varying shapes. Covers
inner: heart, kidneys, intestines, liver, lungs
outer: stomach, heart, intestines
-depending on location, protects, secretes and absorbs
Function of the connective tissue
-provides support to the body
-holds together all of its parts
made up of separated cells divided by non-cellular matric
e.g. bone, cartilage, tendons, ligaments
Function of nervous tissue
-made up of neurons
-neurons carry messages to different parts of the body
e.g. brain, spinal cord, nerves
Function of muscular tissue and types
Smooth:
Walls of stomach and intestines, blood vessels, iris
-involuntary
-non-striated
Skeletal:
Muscle attached to the bone
-voluntary control
-stripes (striated)
Cardiac:
Most of heart (contracts to pump blood)
-non-voluntary
What is a muscle cell/muscle fibre?
Long cylindrical cells with many nuclei making up skeletal muscles
-1 muscle cell=1 elongated cylinder
-they need many nuclei to aid in muscle contraction, elasticity and extensibility
-have many mitochondria to produce energy in order for muscle to contract
-covered by transparent plasma membrane called sarcolemma which is filled with sarcoplasm (special cytoplasm)
-contains 100-1000 myofibrils (striated)
-held together to create muscle bundles
What are myofibrils?
A thread like structure found in the cytoplasm/sarcoplasm of muscle fibres
-made of myofilaments
-myofibrils can be divided into units called sarcomeres due to striations created by myofilaments
What is the sarcoplasmic reticulum
Surrounds the myofibrils and acts as a storage site for calcium ions released during muscle contractions
What are myofilaments?
Composed of protein and is a part of the composition of myofibrils. There are two types:
-thick myosin
-thin actin
-they allow skeletal muscle fibre to contract and relax
What happens when muscle fibre is supplied with sufficient energy?
The thick and thin myofilaments slide past each other in a manner that shorten the myofibril
How do muscles work?
they work with the properties excitability, contractibility, extensibility, elasticity
-be stimulated by a nerve impulse
-shorten in length
-be stretched
-return to their original length
What is the sliding filament theory?
A theory used to explain muscle contractions.
-when muscles contract, the sarcomeres shorten
-this occurs because the actin and myosin filaments slide over one another
Describe how sliding filament theory occurs
-begins with two sarcomeres of a myofibril in a muscle that is relaxed
-as muscle contracts actin (slides) and myosin (have heads) myofilaments slide past one another
-thus, Z lines move close together
-when myofibril reaches max contraction, Z lines are much closer together
-but actin and myosin filaments have not changed their length
- ATP binds to a myosin head, which is released from an actin filament
- Hydrolysis of ATP (into ADP and phosphate) cocks the myosin head
- The myosin head attaches to an actin binding site, in the presence of calcium, and released the ADP and phosphate
- The power stroke, occurring when myosin head returns to it’s original angle after release, slides the actin filament
- 350 myosin heads per myosin
The collective bending of myosin heads which combine to move actin filament relative to myosin results in muscle contraction
What is a z line and A band
Z line
-located at the ends of the sarcomere
- protein discs in the middle of actin filaments
A band
- the length of myosin filament
What is a tendon?
Fibrous, inelastic connective tissue attaching muscles to bones.
How do skeletal muscles work?
-muscles contract, pull bones together
-when one muscles pulls a bone in a direction, another muscle will have to contract and pull in a different direction
-muscles that move skeleton work in pairs (antagonists)
Describe antagonist muscles
Muscle that has an action opposite to that of the prime mover
e.g. Muscles of the upper arm (bicep contracts and triceps must the relax)
Hamstring and quads are also antagonistic pairs of muscles
What is the origin
The end of the muscle fixed to the stationary bone
What is the belly
The fleshy portion of the muscle between the tendons and the origin
What is the insertion
The attachment to the moveable bone of the other end of the muscle to the origin
What is the agonist/prime mover
Muscle causing the desired action
e.g. biceps, moves the forearm, contracting causing triceps to relax
What is the synergist
A muscle that acts indirectly in steadying a joint during a particular
-may produce same movement as prime mover
-may steady a joint during movement
e.g. wrist would bend when fist clenches without the muscles because the muscles in the finger run over the whole of the hand, the wrist is then immobilised
What is a fixator?
A muscle that contracts to immobilise a joint
e.g. the many muscles attaching the scapula to the axial skeleton, holding it firmly so that when arm muscles contract, only their insertion are moved
What is muscle tone
Partial muscle contraction of skeletal muscles
-caused by many different fibres taking turns to contract
-holds many of our body parts in position
e.g. head is held partial contraction of the neck muscles
What are the functions of muscles
Muscles have a secondary role in holding bone tightly together
-primarily the ligaments job
-stabilise joints
Small muscle hold vertebrae together
-stabilise the spinal column
Sphincters to control the passage of substances
Heat production by involuntarily increasing muscle contraction
-when shivering
What is the function of sphincters
Control movement of substances in and out of passages
Describe light and dark bands in the sarcomere
When the light band is larger, the muscle is more relaxed and as the dark band becomes larger the muscle is contracting
What are the types of synovial joints
Ball and socket: rotations in any direction e.g. hip and shoulder
Condyloid: up and down, side to side e.g. phalanges and metacarpals
Hinge: movement in one plane only e.g. elbow and knee
Pivot: rotation e.g. radius and ulna
Saddle: side to side, back and forth e.g. thumb and palm
Gliding: any direction e.g. carpal
The types of joints
Fibrous (fixed)
fused and fixed bones e.g. skull
Cartilaginous (slightly moving)
adjacent bones held by cartilage e.g.
Synovial (freely moving)
spaces between bones filled with synovial fluid e.g. elbow
