Midterm Week #3 Content Flashcards
How are joints classified by structure?
Joints are classified into three types:
* Fibrous joints – No joint cavity, held by dense connective tissue.
* Cartilaginous joints – No joint cavity, connected by cartilage.
* Synovial joints – Contain a fluid-filled cavity, allowing free movement.
What are the classifications of joints based on function?
Joints are classified into three categories:
* Synarthroses – Immovable (e.g., skull sutures).
* Amphiarthroses – Slightly movable (e.g., intervertebral discs).
* Diarthroses – Freely movable (e.g., knee, shoulder).
What are the characteristics of fibrous joints?
Fibrous joints include:
* Sutures – Found only in the skull, immovable.
* Syndesmoses – Connected by ligaments; movement depends on fiber length.
* Gomphoses – Peg-in-socket joint (e.g., teeth in alveolar sockets).
What are the characteristics of cartilaginous joints?
Cartilaginous joints include:
* Synchondroses – Hyaline cartilage connects bones.
* Symphyses – Fibrocartilage connects bones, allowing limited movement.
What are the seven key features of synovial joints?
Key features include:
* Articular cartilage – Covers bone surfaces.
* Joint cavity – Space containing synovial fluid.
* Articular capsule – Two layers: outer fibrous & inner synovial membrane.
* Synovial fluid – Reduces friction, nourishes cartilage.
* Reinforcing ligaments – Strengthen joints.
* Sensory nerves – Detect pain, stretch.
* Blood supply – Produces synovial fluid.
What is the significance of synovial fluid in joint health?
Synovial fluid:
* Lubricates the joint, reducing friction.
* Provides nutrients to cartilage.
* Contains glycoproteins from fibroblasts.
* Absorbs shock via weeping lubrication.
* Prevents overheating and damage from compressive forces.
What is the function of articular discs?
Articular discs (menisci):
* Improve fit between articulating bones.
* Absorb shock, distribute pressure.
What are bursae and their function?
Bursae are flattened sacs lined with synovial membrane that:
* Reduce friction between bones, ligaments, and tendons.
What are tendon sheaths?
Tendon sheaths are elongated bursae that:
* Wrap around tendons to reduce friction in high-motion areas.
Describe gliding movements in the body.
Gliding movements occur when:
* Flat bone surfaces slide over each other (e.g., carpals, tarsals).
Fill in the blank: Flexion decreases the _______.
[joint angle]
What is the action of the deltoid muscle?
The deltoid muscle performs abduction of the arm.
What type of joint is the temporomandibular joint (TMJ)?
The TMJ is a modified hinge joint.
What are common joint injuries?
Common joint injuries include:
* Torn cartilage.
* Sprains.
* Dislocation.
True or False: Osteoarthritis is an autoimmune disease.
False
What changes occur in joints due to aging?
Aging leads to:
* Decreased cartilage thickness and elasticity.
* Decline in synovial fluid production.
* Stiffer ligaments and tendons.
What are the fascicle arrangements in skeletal muscles?
Fascicle arrangements include:
* Circular (Sphincters).
* Convergent.
* Parallel.
* Fusiform.
* Pennate (Unipennate, Bipennate, Multipennate).
What are the components of a muscle lever system?
The components of a muscle lever system are:
* Lever (Bone).
* Fulcrum (Joint).
* Effort (Muscle Contraction).
* Load (Body Part/Resistance).
What determines the action of a muscle across a joint?
The position of the muscle relative to the joint determines its action.
Define agonist in muscle action.
Agonist (Prime Mover) – Main muscle performing the movement.
What is the role of synergists in muscle action?
Synergists help the agonist by adding force or reducing unwanted movement.
What criteria are used for naming muscles?
Muscles are named based on:
* Location.
* Shape.
* Size.
* Direction of Fibers.
* Number of Origins.
* Action.
What is the action of the orbicularis oris muscle?
The orbicularis oris muscle closes and puckers the lips.
Identify the origin and insertion of the masseter muscle.
Origin: Zygomatic arch.
Insertion: Mandible.
What is the action of the sternocleidomastoid muscle?
The sternocleidomastoid muscle rotates the head and flexes the neck.
