Week 4 Flashcards
What are the four structural categories of joints?
- Fibrous
- Cartilaginous
- Bony
- Synovial
What are the three functional categories of joints?
- Synarthrosis (fibrous or cartilaginous, can ossify forming a bony joint)
- Amphiarthrosis (fibrous or cartilaginous)
- Diarthrosis (synovial)
What are the main components of a synovial joint and what are their functions?
- Fibrous joint capsule - Provides stability and connects to the synovial membrane.
- Synovial membrane - Produces synovial fluid.
- Articulator cartilages - Reduces friction and prevents bone to bone contact.
- Joint cavity - Filled with synovial fluid which lubricates, distributes nutrients and provides shock absorption.
What are the accessory structures of the synovial joint?
Ligaments, tendons, bursae (small, thin sacks filled with synovial fluid that reduce friction and provide shock absorption), fat pads and cartilages.
What are the types of movement found in synovial joints?
- Flexion
- Extension (and hyperextension)
- Abduction (away from body)
- Adduction (towards body)
- Supination (wrist facing up)
- Pronation (wrist facing down)
- Rotation (pivot joint movement)
- Circumduction (Circular movements)
- Depression (lowering)
- Elevation (raising)
What is dislocation?
When articulating surfaces are forced out of position.
What are the possible types of articular motion?
- Linear (gliding)
- Angular motion
- Rotational motion
What are joints called depending on the axes of motion they allow?
- Monaxial (1 type of articular motion)
- Biaxial (2 types of articular motion)
- Triaxial (3 types of articular motion)
List the synovial joint types that are monaxial, biaxial and triaxial respectively.
Monaxial: Hinge, gliding and pivot.
Biaxial: Condyloid and saddle.
Triaxial: Ball and socket.
What are the main joints in the body and their type?
Elbow and knee: Hinge.
Shoulder and Hip: Ball and socket.
Define “Rheumatism”
Disorders or conditions causing chronic, often intermittent pain affecting the joints or connective tissue.
Define “Arthritis”
All rheumatic diseases that affect synovial joints.
What are bulging and herniated discs?
Occurs when the nucleus of the intervertebral disc pushes the annulus outwards (bulging) or breaks the annuls (herniated).
What happens during rigor mortis?
The produces of ATP quickly halts due to lack of oxygen, the metabolic processes for muscle relaxation require ATP and the body stiffens.
What are the four common properties of muscle tissue?
- Excitability - Responds to chemical stimulus from nerve system.
- Contractibility - Ability to shorten.
- Extensibility - Ability to stretch.
- Elasticity - Ability to recoil.
What are the main functions of skeletal muscle?
- Producing movement.
- Maintaining posture.
- Supporting soft tissue - Primarily in the abdominopelvic area.
- Guarding body entrances and exits - Swallowing, defecating and urinating.
- Maintaining body temperature - Contractions use energy, heat energy lost maintains temperature.
- Storing nutrients
Explain the structure of a skeletal muscle at the organ level.
- Epimysium - Dense layer of collagen surrounds muscle.
- Perimysium - Divides muscle into compartments called fascicle.
- Endomysium - Connective tissue layer sounding muscle fascicle.
Explain the structure of the skeletal muscle fascicle.
- Surrounded by perimysium.
2. Muscle fibres surrounded by endomysium.
What do skeletal muscle cell fibrils contain?
Actin (thin myofilaments), myosin (thick myofilaments) and titin (spring-like proteins associated with myosin) which repeat, these are called sarcomeres.
What are the bands and lines of sarcomeres?
- I band - Region containing only actin filaments.
- A band - Regions of overlapping actin and myosin filaments.
- H band - Region containing only myosin filaments.
- M line - Centre of the A band, proteins that connect myosin.
- Z line - Centre of the I band, connects actin (marks the boundaries of sarcomeres).
How do muscles contract?
- Nervous system propagates signal for contraction via neuromuscular junction and t-tubes.
- Sarcoplasmic reticulum releases stored calcium ions (Ca2+) into the cytosol.
- The troponin complex that prevents the myosin heads from binding to actin changes shape in response to calcium ions
- Myosin heads bind to actin and flex towards the midline (power stroke), this sliding causes the sarcomeres to contract.
What are tendons and aponeurosis?
Bundles of epimysium, perimysium and endomysium come together into bundles (tendons) or sheets (aponeurosis) that normally attach to bones.
What are myoblasts?
Muscle stem cells that fuse during development to create muscle cell fibres, some do not fuse allowing for enlargement or division to repair damage in adulthood.
How do muscles relax?
The intracellular calcium ions are reabsorbed into the terminal cisternae of the sarcoplasmic reticulum, the troponin complex returns to a shape that prevents myosin heads binding to actin.
What is a neuromuscular junction? (NMJ)
The synapse between a motor neuron and a skeletal muscle cell.
Made up of the axon terminal of a motor neuron and a region of the sarcolemma called the motor end plate.
Acetylcholine is released into the synaptic cleft generating an action potential in the skeletal muscle cell.
What is excitation-contraction coupling?
The link between the generation of an action potential in the sarcolemma and the start of a muscle contraction.
What is isotonic contraction and the variations of?
Isotonic contraction is muscle contraction where muscles increase tension AND the skeletal muscle changes length.
Isotonic concentric contraction - Muscle increases tension but shortens in length.
Isotonic eccentric contraction - Muscle increases tension but increases in length.
What is isometric contraction?
Isometric contraction is muscle contraction where muscles increase tension but do not change length.
What differences does cardiac muscle have from skeletal muscle?
- Smaller.
- Cardiac muscle cells have only one nucleus.
- Typically branched in structure as opposed to bundled.
- No terminal cisternae (stores calcium ions).
- Large amounts of mitochondria.
- Each cardiac cell contacts with several others at intercalated discs.
- Have pacemaker cells.
- Involuntarily controlled.
Where is smooth muscle mostly found?
- Integumentary system - blood vessels.
- Cardiovascular system - blood vessels.
- Respiratory system - contract/relax to alter diameters of respiratory pathways.
- Digestive system - Intestines, gallbladder, urinary, sphincters.
- Reproductive system - In males, movement of sperm, in females, movement of liquids along reproductive tract. (Also expel the fetus).
What are the differences between smooth muscle and skeletal/cardiac?
- Spontaneous contraction.
- No sarcomeres.
- Bunch up rather than shorten.
- Little nervous innervation.
- Mainly hormonal control.
What are the four classifications of muscle fascicles?
- Parallel muscles - parallel fibres, most skeletal muscles are parallel, most have tendons at each end.
- Convergent muscles - Fan shaped, tendons on one end, broad attachment at the other end.
- Pennate muscles - Form a common angle with tendon, can be unipennate, bipennate, multipennate.
- Circular muscles - Ring of muscle.
What are the 3 classes of levers?
1st class - Fulcrum is centred between load and applied force (head and neck or seesaw).
2nd class - Fulcrum is at the end, load is in front of applied force (ankle or wheel barrow).
3nd class - Most common, fulcrum is at one end which is just behind applied force, load is at the opposite end (bicep brachii).
Define “insertion” (muscles).
Insertion usually distal and moveable end of action.
Define “origin” (muscles).
Origin usually proximal and fixed end of muscle action
Define “agonist” (muscles).
Prime mover (major involvement in movement).
Define “antagonist” (muscles).
Opposes prime mover produces opposite action.
Define “synergist” (muscles).
Assists prime mover in action.
What happens to skeletal muscle when you age?
- Become smaller
- Become less elastic
- Exercise tolerance decreases
- Recovery from injury decreases
Skeletal muscle cells are multinucleated, true or false?
True.
