Unit Three Flashcards
Other words for joints
Articulations or arthroses
A joint in contact between:
two bones
bones and cartilage
or bone and teeth
What are structural classification for joints based on?
- The presence or absence of a synovial cavity
- The type of connective tissue that binds the bones together
What type of joints do sutures have?
Fibrous joints
Explain fibrous joints
No synovial cavity, bones held together by fibrous connective tissue
Explain Cartilaginous joints
No synovial cavity, bones held together by cartilage
Explain Synovial joints
Presence of a synovial cavity, bones united by dense irregular connective tissue of an articular capsule
What is Synarthrosis?
Immovable joint
What is Amphiarthrosis?
Slightly movable joint
What is Diarthrosis?
Freely movable joints
What is Syndesmoses?
Fibrous joints with greater distance between the articulating bones and more fibrous connective tissue than sutures
What type of movement do synovial joints have?
Diarthrosis
What is gomphoses?
Fibrous joints between the roots of the teeth and the sockets in the mandible and maxillae
What is Synchondroses?
Cartilaginous joints connected by hyaline cartilage that have synarthroses movement
What is Symphyses?
Cartilaginous joints that are connected by a flat disc of fibrocartilage, they have amphiarthroses movement
What does synovial fluid allow?
A joint to be freely moveable
What is the function of the articular capsule?
Unite the articulating bones
What is the articular capsule composed of?
Outer fibrous layer called: fibrous capsule
Inner layer called: synovial membrane
What secretes the synovial fluid>
Synovial membrane
How are people “double-jointed”
Increased elastic fibers in articular capsule makes it more flexibility in their articular capsules and ligaments (prob from increased elastic fibers)
What is Synovial Fluid composed of?
Hyaluronic acid (GAGs), interstitial fluid from blood plasma, WBCs
Function of synovial fluid
reduce friction, absorbs shock, and provides articulating cartilage with O2 and nutrients
What are menisci?
Disc of fibrocartilage between the articular surfaces of bones, attached to the articular capsule
What is the process of cartilage receiving oxygen and nutrients via diffusion called?
Imbibition
Sprain vs. Strain
Sprain: Stretching or tearing of the ligament in a joint
Strain: Stretching or tearing of the muscle
What are sac-like structures filled with synovial fluid called?
Bursa
What is the name of an inflamed bursa?
Bursitis
Where do you find bursa?
Between bones and skin, tendons, muscle or ligaments
What are tendon sheaths?
Tubelike bursae that wrap around tendons
What are the movements of the synovial joints?
Gliding, angular movements, rotation, special movements
What is the motion of gliding?
Flat bone moves back-and-forth and side-to-side on another bone
What is the motion of angular movements?
increase or decrease in angle between articulating bones
What is flexion?
Decrease in the angle
What is extension?
Increase in the angle
What is lateral flexion?
Flexion that occurs in the frontal plane (moving the side of head closer to the shoulder)
What is abduction?
Movement of a bone away from the midline
What is adduction?
Movement of a bone towards the midline
What is circumduction?
Movement of distal end of bone/body part in a circle
What is rotation?
Movement where the bone revolves around its own longitudinal axis
What are special movements?
Movements that occur at certain joints
What is elevation?
Moving the body part upward
What is depression?
Moving the body part downward
What is protraction?
Moving the body part anteriorly in transverse plane
What is retraction?
Moving body part posteriorly to normal anatomical position
What is inversion?
Turning the soles of the feet medially
What is eversion?
Turning the soles of the foot laterally/outward
What is dorsiflexion?
Bending the foot upwards
What is plantarflexion?
Bending the foot downward
What is supination?
Turning the forearm until the palm faces upwards
What is pronation?
Turning the forearm until the palm faces downward
What is opposition?
Movement of the thumb to touch the other fingers
What are the types of synovial joints?
Planar joints
Hinge joints
Pivot joints
Condyloid joints
Saddle Joints
Ball-in-socket joints
What is planar joints?
Flat articulating surfaces that permit gliding movement in all planes
Examples of planar joints
Intertarsal, intercarpal, sternoclavicular and acromioclavicular joints
What are hinge joints?
Round articulating surface fits into another concave articulating surface
(Only permits flexion and extension)
Examples of hinge joints
Elbow, knee, angle, and finger joints
What is a pivot joint?
Rounded or pointed surface that fits into a ring formed by bone and ligaments
Examples of pivot joints
Atlantis and Axis joint
Proximal radioulnar joints
What are condyloid joints?
Oval-shaped projection that fits into an oval shaped depression
Examples of condyloid joints
Radiocarpal and metacarpophalangeal joints
What are saddle joints?
Articular surface of one bone is saddle-shaped and other articulating surface fits into the saddle
Examples of saddle joints
Only one: Trapezium and first metacarpal in the thumb
What are ball-in-socket joints?
Ball-like surface of one bone sits in cuplike depression of another
Examples of ball-in-socket joints
Shoulder (glenohumeral joint) and hip joint
What can change ROM (range of motion)?
- Tight or lose joint ligaments, capsule or tendons
- Hormones (relaxin for birthing process)
- Disuse of the joints
What is special about the temporomandibular joint?
It is both a hinge and planar joint
What joint has the most ROM?
The glenohumeral joint of the shoulder
What is the glenoid labrum?
Interarticular fibrocartilage ring over the glenoid fossa (deepings and enlarges the glenoid cavity)
What are the joints that make up the knee joint?
Lateral tibiofemoral and medial tibiofemoral joint are hinge joints
And patellofemoral joint is a planar joint
What leads to arthritis?
(As you get older): there is a decrease in synovial fluid, thinning articular cartilage, and decrease of flexibility of ligaments
What is arthroplasty?
Joint replacement surgery where the end of one or both bones are replaced with metal, ceramic or plastic components
What are the functions of muscle?
- Body movement
- Stabilize body position
- Storing and moving substances
- Generating heat
What percentage of your weight is muscle?
40-50%
Properties of muscle
Electrical excitability, contractility, extensibility, elasticity
What are fascia?
Dense irregular fibrous connective tissue that supports, surrounds and protects muscles and other organs
What are endomysium?
Loose connective tissue that extends from the deep fascia. They protect and provide capillaries to muscle fibers
What are Fascicles?
Muscle fibers that are bundles together
What are perimysium?
Connective tissue that surrounds and provides blood to fascicles
What are epimysium?
Strong connective tissue that surrounds muscles
What forms tendons?
Endomysium, perimysium, and epimysium extends beyond the muscle to form tendons
How do muscles grow?
Hypertrophy - enlargement of muscle fibers due to increase myofibrils (NOT increase in the number of fibers)
What is the plasma membrane of the muscle cell called?
Sarcolemma
What are transverse (T) tubules?
Tunnels from the sarcolemma to the center of each fiber
What are the function of T-tubules?
Deliver the action potential from the nerve to the contractile apparatus of the entire fiber (allows for contraction)
What is the cytoplasm of the muscle fiber called?
Sarcoplasm
What is myoglobin?
Molecule found only in muscle that delivers oxygen to the mitochondria of the muscle cells to produce ATP
What are myofibrils?
Contractile organelles organized in bundles
What are sarcomeres?
Organized collection of actin and myosin filaments that overlap each other
What is the endoplasmic reticulum in fibers called?
Sarcoplasmic reticulum
What are sarcoplasmic reticulum?
Membranous sacs that encircle myofibril. Function to store calcium ions
What is the functional unit of muscle physiology?
Sarcomere
What are the Z-Line and M-Line?
Z-line: Forms the end of plates of a sarcomere and contract between adjacent sarcomeres. Actin filament attach to Z-Line
M-Line: Located in the middle of the sarcomere. Myosin filament are connected to one another here
What are the 3 bands or zones of sarcomere?
I band: consists of only actin filaments adjacent to their attachment to the Z-Line
A Band - Consists of overlapping myosin and actin filaments.
H Zone: Lies in the middle of the A band and consists of only myosin fibers
What bands/zones change during contraction and relaxation?
I-band and H-Zone change. But A-Band does not change
What proteins are present in the actin filament?
Actin, tropomyosin and troponin
What is tropomyosin
Found in the grooves of the actin that consists of a binding site that interacts with the myosin head
Explain Troponin
Consists of 3 binding sites:
T portion that binds troponin to tropomyosin
C portion that binds to calcium ions
I portion that inhibits the interaction of actin and myosin
Which filaments are thicker: myosin or actin?
Myosin filaments
What does tropomyosin and troponin do?
Inhibit binding before the initiation of a contraction
How does the initiation of a contraction start?
neurotransmitter binds at the myoneural junction and causes the muscle membrane to depolarize and the release of calcium ions from the sarcoplasmic reticulum
Calcium ions bind to troponin and allows for actin to bind to myosin
What is ATP’s role in muscle contraction?
ATP binds to myosin head and causes dissociation from the actin. ATP then hydrolyzed, releasing energy causing myosin head to bind to new actin
What is the power stroke?
Process of ATP releasing energy and myosin head to attach to new actin site repeatedly causing the muscle contraction
When does contraction end?
When the sarcomere is maximally shortened or the calcium ions are used up
What causes rigor mortis?
Myosin heads remain attached to actin at time of death. As SR breaks down high concentration of calcium ions surround myofibril and muscles stiffen within hours and remain stiff until muscle proteins begin to be broken down by enzymes 15-25 hours post mortem
What other ways do fiber produce ATP?
Creatine phosphate, anaerobic cellular respiration and aerobic cellular respiration
What does Creative phosphate do for muscles?
Energy-rich molecule only found in muscle tissue. It provides the leftover ADP with a phosphate group to make it to a useful energy molecule: ATP
What is the “burn” sensation while working out?
Microscopic tears in the muscle fibers upon eccentric contraction
How much energy can anaerobic respiration provide?
About 30-40 seconds of maximal muscle activity
How much energy does ATP provide?
About 15 seconds of muscle contraction
Types of muscle fibers
- Slow oxidative fibers
- Fast oxidative-glycolytic fibers
- Fast glycolytic fibers
About Slow Oxidative fibers
Contracts slowly
Favors aerobic oxidation of glucose
Resistant to fatigue
Make up postural muscles
About Fast Oxidative-Glycolytic fibers
Generates ATP from aerobic and anaerobic respiration
Rate of contraction is 3-5x faster than slow oxidative fibers
Found in muscle of lower limbs
About Fast Glycolytic fibers
- Contracts relatively quickly
- Largest in diameter and contain most myofibrils
- Favors glycolysis over oxidation because they’re abundant glycolytic enzymes
- Low fatigue resistance
- Found in upper limb muscles
Colors of the 3 muscle fibers
Slow oxidative: Reddish-brown
Fast oxidative-glycolytic: tannish-pink
Fast glycolytic: Whitish
What is a Lower Motor Neuron?
A neuron that sends its axon from the central nervous system to the muscle
What is the neuromuscular junction?
The physiological junction between the nervous system and the muscular system
What is the anatomical junction between the neuron and the muscle fiber?
The motor end plate
What is the neurotransmitter that transmits info across the synapse?
Acetylcholine (Ach)
What happens when the action potential reaches the axon terminal
- The synaptic vesicles are released from the neuron
- Voltage gated Ca+ channels in presynaptic cell membrane open
- Influx of Ca+ ions from synaptic cleft triggers the exocytosis of the synaptic vesicles releasing Ach into synaptic cleft
- Ach diffuses across the synaptic cleft. And binds to and opens Ach channel making influx of Sodium ions into muscle fiber
What kind of channel is the Ach channel?
Chemically-gated positive ion channel
What happens when sodium ions go into muscle fiber?
- they produce an end plate potential which triggers the propagation of a muscle action potential
- Acetylcholinesterase breaks down Ach and it’s recycled into the axon terminal
What is Myasthenia Gravis?
Auto-immune disease where antibodies attack the Ach channels. Resulting in paralysis of the muscles
What toxin is used in botox?
Botulinum
How do the myosin heads become exposed?
Calcium ions from the sarcoplasmic reticulum go into the muscle fiber and attach to the troponin.
Which shifts the tropomyosin and exposes the actin filament.
Does Cardiac muscle depend on Ach?
No. It contracts when stimulated by its own auto-rhythmic muscle fibers
Do skeletal muscles have T-tubles?
No. They have caveolae which contain calcium ions
Why is the duration of contraction and relaxation of smooth muscle longer?
Because they lack T-tubules so it takes longer for calcium ions to reach the filaments
What type of muscle can fully regenerate if injured?
Smooth muscle
What muscle can shorten and stretch the most?
Smooth muscle
